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Total Synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction

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Chinese Journal of Chemistry 2024年第11期42卷 1267-1274页

作者： Yuye Chen Wenqing Chen Zhiting Zhang Jing Xu shenzhen Grubbs Institute and Department of Chemistry and Guangming Advanced Research Institute and Guangdong Provincial key laboratory of Catalysis and shenzhen key laboratory of Small Molecule drug Discovery and Synthesis Southern University of Science and TechnologyShenzhenGuangdong518055 China

As one of the most common structural motifs in natural products,cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary divinyl carbinols(TDCs)as ***,straightforward method for transforming unfunctionalized TDCs to their corresponding cyclopentenones is currently ***,we wish to report the total syntheses of four structurally distinct terpenoids,namely laurane-type marine sesquiterpenoids isolaurene,debromoaplysin and aplysin,and guaiane sesquiterpenoid guaiadienone A,all using a novel synthetic method,named oxidative Nazarov cyclization,as the key *** work demonstrated our robust method is suitable for synthesizing various highly substituted cyclopentenones.

关键词： Total synthesis Synthetic methods Sesquiterpenoids Oxidative Nazarov reaction Electrocyclization Oxoammonium salt Pericyclic reaction Annulation

Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

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Science China Chemistry 2024年第7期67卷 2382-2391页

作者： Ke-Wei Chen Jia-Nan Chen Jun Zhang Chao Wang Tian-Yu Sun Yun-Dong Wu key laboratory of Computational Chemistry and drug Design State Key Laboratory of Chemical OncogenomicSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Changping laboratory Beijing 102200China

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site ***,its catalytic(C)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(NC)subunit binds a second substrate and promotes the conversion of the intermediate in the C subunit into the final *** the release of the product,the C subunit becomes the NC subunit,and the previous NC subunit becomes the C *** elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction *** simulations indicate that the substrate in the NC subunit induces W185 and Y141 adopting an open conformation in the C *** opening of W185(C)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(C)creates an unfavorable environment for product binding,promoting its *** interaction network analysis reveals that the substrate in the NC subunit can induce conformational changes through a conserved water chain at the interface.

关键词： enzyme catalysis molecular dynamics cooperative effect pre-reaction state

Applications of genetic code expansion technology in eukaryotes

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Protein & Cell 2024年第5期15卷 331-363页

作者： Qiao-ru Guo Yu J.Cao State key laboratory of Chemical Oncogenomic Guangdong Provincial Key Laboratory of Chemical GenomicsPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China

Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to *** eukaryotes,genetic code expansion(GCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic *** is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch ***,there is keen interest in utilizing GCE in eukaryotic *** review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.

关键词： genetic code expansion unnatural amino acid eukaryotes basic research therapeutic applications

High-repetition-rate and high-power efficient picosecond thin-disk regenerative amplifier

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High Power Laser Science and Engineering 2024年第2期12卷 16-23页

作者： Sizhi Xu Yubo Gao Xing Liu Yewang Chen Deqin Ouyang Junqing Zhao Minqiu Liu Xu Wu Chunyu Guo Cangtao Zhou Qitao Lue Shuangchen Ruan key laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes Sino-German College of Intelligent ManufacturingShenzhen Technology UniversityShenzhenChina Han’s Laser Technology Industry Group Co. Ltd.ShenzhenChina shenzhen key laboratory of Laser Engineering College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenChina shenzhen key laboratory of Ultraintense Laser and Advanced Material Technology College of Engineering PhysicsShenzhen Technology UniversityShenzhenChina

We present an effective approach to realize a highly efficient,high-power and chirped pulse amplification-free ultrafast ytterbium-doped yttrium aluminum garnet thin-disk regenerative amplifier pumped by a zero-phonon line 969 nm laser *** amplifier delivers an output power exceeding 154 W at a pulse repetition rate of 1 MHz with custom-designed 48 pump *** exceptional thermal management on the thin disk through high-quality bonding,efficient heat dissipation and a fully locked spectrum collectively contributes to achieving a remarkable optical-to-optical efficiency of 61%and a near-diffraction-limit beam quality with an M2 factor of *** the best of our knowledge,this represents the highest conversion efficiency reported in ultrafast thin-disk regenerative ***,the amplifier operates at room temperature and exhibits exceptional stability,with root mean square stability of less than 0.33%.This study significantly represents advances in the field of laser amplification systems,particularly in terms of efficiency and average *** advantageous combination of high efficiency and diffraction limitation positions the thin-disk regenerative amplifier as a promising solution for a wide range of scientific and industrial applications.

关键词： high efficiency high power picosecond laser regenerative amplifier thin-disk laser

Ultrafast pulse-dilation framing camera and its application for time-resolved X-ray diagnostic

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Nuclear Science and Techniques 2024年第7期35卷 101-114页

作者： Hou-Zhi Cai Qiu-Yan Luo Kai-Xuan Lin Xuan Deng Jun-Kai Liu Kai-Zhi Yang Dong Wang Jia-Jie Chen Jia-Heng Wang Jing-Hua Long Li-Hong Niu Yun-Fei Lei Jin-Yuan Liu key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Shenzhen Key Laboratory of Photonics and BiophotonicsCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China

An ultrafast framing camera with a pulse-dilation device,a microchannel plate(MCP)imager,and an electronic imaging system were *** camera achieved a temporal resolution of 10 ps by using a pulse-dilation device and gated MCP imager,and a spatial resolution of 100μm by using an electronic imaging system comprising combined magnetic *** spatial resolution characteristics of the camera were studied both theoretically and *** results showed that the camera with combined magnetic lenses reduced the field curvature and acquired a larger working area.A working area with a diameter of 53 mm was created by applying four magnetic lenses to the ***,the camera was used to detect the X-rays produced by the laser-targeting *** diagnostic results indicated that the width of the X-ray pulse was approximately 18 ps.

关键词： Inertial confinement fusion Plasma diagnostics Framing camera Combined lenses Pulse-dilation

Dynamic Response of Foundations during Startup of High-Frequency Tunnel Equipment

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 821-844页

作者： Dawei Ruan Mingwei Hu College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518060China State key laboratory of Intelligent Geotechnics and Tunnelling Shenzhen UniversityShenzhen518060China key laboratory of Coastal Urban Resilient Infrastructures of Ministry of Education Shenzhen UniversityShenzhen518060China Underground Polis Academy Shenzhen UniversityShenzhen518060China shenzhen key laboratory of Green Efficient and Intelligent Construction of Underground Metro StationShenzhen UniversityShenzhen518060China

The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex *** vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the *** high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe *** article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element *** proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through *** into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are *** validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance *** design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.

关键词： Tunnel equipment high-frequency units startup conditions transient dynamics dynamic response foundation design

Lightweight Object Detection Networks for UAV Aerial Images Based on YOLO

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Chinese Journal of Electronics 2024年第4期33卷 997-1009页

作者： Yanshan LI Jiarong WANG Kunhua ZHANG Jiawei YI Miaomiao WEI Lirong ZHENG Weixin XIE ATR National key laboratory of Defense Technology Shenzhen University Guangdong key laboratory of Intelligent Information Processing Shenzhen University

Existing high-precision object detection algorithms for UAV(unmanned aerial vehicle) aerial images often have a large number of parameters and heavy weight, which makes it difficult to be applied to mobile *** propose three YOLO-based lightweight object detection networks for UAVs, named YOLO-L, YOLO-S, and YOLO-M, respectively. In YOLO-L, we adopt a deconvolution approach to explore suitable upsampling rules during training to improve the detection accuracy. The convolution-batch normalization-Si LU activation function(CBS)structure is replaced with Ghost CBS to reduce the number of parameters and weight, meanwhile Maxpool maximum pooling operation is proposed to replace the CBS structure to avoid generating parameters and weight. YOLO-S greatly reduces the weight of the network by directly introducing CSPGhost Neck residual structures, so that the parameters and weight are respectively decreased by about 15% at the expense of 2.4% mAP. And YOLO-M adopts the CSPGhost Neck residual structure and deconvolution to reduce parameters by 5.6% and weight by 5.7%, while m AP only by 1.8%. The results show that the three lightweight detection networks proposed in this paper have good performance in UAV aerial image object detection task.

关键词： Training YOLO Deconvolution Accuracy Object detection Autonomous aerial vehicles Feature extraction

Microstructured Cantilever Probe on Optical Fiber Tip for Microforce Sensor

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Photonic Sensors 2024年第2期14卷 89-99页

作者： Famei WANG Changrui LIAO Mengqiang ZOU Dejun LIU Haoqiang HUANG Chao LIU Yiping WANG shenzhen key laboratory of Ultrafast Laser Micro/Nano Manufacturing Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education/Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China shenzhen key laboratory of Photonic Devices and Sensing Systems for Internet of Things Guangdong and Hong Kong Joint Research Centre for Optical Fibre SensorsState Key Laboratory of Radio Frequency Heterogeneous IntegrationShenzhen UniversityShenzhen 518060China School of Electronics Science Northeast Petroleum UniversityDaqing 163318China

Benefiting from the great advances of the femtosecond laser two-photon polymerization(TPP)technology,customized microcantilever probes can be accurately 3-dimensional(3D)manufactured at the nanoscale size and thus have exhibited considerable potentials in the fields of microforce,micro-vibration,and microforce *** this work,a controllable microstructured cantilever probe on an optical fiber tip for microforce detection is demonstrated both theoretically and *** static performances of the probe are firstly investigated based on the finite element method(FEM),which provides the basis for the structural *** proposed cantilever probe is then 3D printed by means of the TPP *** experimental results show that the elastic constant k of the proposed cantilever probe can be actively tuned from 2.46N/m to 62.35N/*** force sensitivity is 2.5nm/μN,the Q-factor is 368.93,and the detection limit is ***,the mechanical properties of the cantilever probe can be flexibly adjusted by the geometric configuration of the ***,it has an enormous potential for matching the mechanical properties of biological samples in the direct contact mode.

关键词： Optical fiber sensor microforce sensing microstructured cantilever two-photon polymerization

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang Ji Yuan Xue-Lian Fu Jing-Jing Chen Jing Hu Zhou-Guang Lu Chen Liu Guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China shenzhen key laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution