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Magnetic wrinkled organosilica-based metal-enzyme integrated catalysts for enhanced chemoenzymatic catalysis

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Green Synthesis and Catalysis

Green Synthesis and Catalysis 2024年第2期5卷 122-125页

作者： Yunting liu Na Guo Weixi Kong Shiqi Gao Guanhua liu Liya Zhou Jing Gaoa Yanjun Jiang School of Chemical Engineering and Technology Hebei University of TechnologyTianjin 300130China Tianjin Key Laboratory of Chemical Process Safety Hebei University of TechnologyTianjin 300130China

Core-shell structured magnetic wrinkled organosilica-based metal-enzyme integrated catalysts were synthesized,and their catalytic performances were studied in the chemoenzymatic dynamic kinetic resolution of chiral amines in an organic solvent,as well as in the chemoenzymatic synthesis of chiral alcohols in *** studies revealed the important influence of their tunable structure and composition on the optimization of activity,stability,and recyclability in chemoenzymatic catalysis.

关键词： Magnetic wrinkled organosilica Chemoenzymatic catalysis Co-immobilization Asymmetric synthesis Chiral amines/alcohols Dynamic kinetic resolution Nanomaterials

Analysis of the electron transfer pathway in small laccase by EPR and UV-vis spectroscopy coupled with redox titration

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Magnetic Resonance Letters 2024年第3期4卷 52-59页

作者： Lu Yu Aokun liu Jian Kuang Ruotong Wei Zhiwen Wang Changlin Tian High Magnetic Field Laboratory Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China Department of Endocrinology Institute of Endocrine and Metabolic DiseaseThe First Affiliated Hospital of USTCDivision of Life Sciences and MedicineHefei National Research Center for Physical Sciences at the MicroscaleJoint Center for Biological Analytical ChemistryAnhui Engineering Laboratory of Peptide DrugAnhui Laboratory of Advanced Photonic Science and TechnologyUniversity of Science and Technology of ChinaHefei230026China

Bacterial small laccases(SLAC) are promising industrial biocatalysts due to their ability to oxidize a broad range of substrates with exceptional thermostability and tolerance for alkaline p H. Electron transfer between substrate, copper centers, and O2is one of the key steps in the catalytic turnover of SLAC. However, limited research has been conducted on the electron transfer pathway of SLAC and SLAC-catalyzed reactions, hindering further engineering of SLAC to produce tunable biocatalysts for novel applications. Herein, the combinational use of electron paramagnetic resonance(EPR) and ultraviolet-visible(UV-vis) spectroscopic methods coupled with redox titration were employed to monitor the electron transfer processes and obtain further insights into the electron transfer pathway in SLAC. The reduction potentials for type 1 copper(T1Cu), type 2 copper(T2Cu) and type 3copper(T3Cu) were determined to be 367 ± 2 mV, 378 ± 5 m V and 403 ± 2 mV,respectively. Moreover, the reduction potential of a selected substrate of SLAC, hydroquinone(HQ), was determined to be 288 mV using cyclic voltammetry(CV). In this way, an electron transfer pathway was identified based on the reduction potentials. Specifically,electrons are transferred from HQ to T1Cu, then to T2Cu and T3Cu, and finally to ***, superhyperfine splitting observed via EPR during redox titration indicated a modification in the covalency of T2Cu upon electron uptake, suggesting a conformational alteration in the protein environment surrounding the copper sites, which could potentially influence the reduction potential of the copper sites during catalytic processes. The results presented here not only provide a comprehensive method for analyzing the electron transfer pathway in metalloenzymes through reduction potential measurements, but also offer valuable insights for further engineering and directed evolution studies of SLAC in the aim for biotechnological and industrial applications.

关键词： Electron paramagnetic resonance Redox titration Electron transfer Reduction Potential Small laccase

Design and experiment of anti-adhesion rototiller based on staggered double-roller scraping

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 165-175页

作者： Jian Cheng Junfang Xia Kan Zheng Guoyang liu Youshuai Wei Juan Zou College of Engineering Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Agricultural Equipment in Mid-lower Reaches of Yangtze River Ministry of Agriculture and Rural AffairsWuhan 430070China Hubei academy of agricultural sciences institute of food crops Wuhan 430070China

In order to solve the serious problem of soil adhering blade roller in the middle and lower reaches of Yangtze River,the anti-adhesion rototiller based on staggered double-roller scraping(ARSDS)was designed by mechanical scraping *** volume equation for scraping the soil adhesion part with staggered rotary blades was *** mechanical conditions for separation of soil adhesion part from blade roller were clarified,and the contact time between rotary blade and soil during rotary tillage was *** this way,the key parameters affecting soil adhering on and separating from the blade roller were determined,which were rotational speed,cutting pitch and tillage *** spatial and temporal trajectory changes for the sidelong section edge of staggered rotary blades were analyzed,so that the rotary blade arrangement was *** the discrete element method,selecting the soil adhesion mass on the staggered blade rollers as the response value established prediction model by Box-Behnken design *** example,taking the tillage depth of 14 cm for wheat cultivation in the middle and lower reaches of Yangtze River,the optimal combination of parameters was determined to be 230 r/min and 10 cm for rotational speed and cutting pitch,*** this time,the soil adhesion mass was 4566.67 *** the meantime,the process of soil particles adhering staggered blade rollers and rotary blades scraping off the adhering soil were *** experiments have shown that the operation quality of ARSDS met the requirements of rototiller performance *** the rice stubble field of high water moisture,the soil adhesion mass was 13.455 kg and 38.215 kg for ARSDS and conventional rototiller,respectively,which indicated that ARSDS effectively reducing soil adhesion *** research results can provide technical support for the design of rototiller reducing soil adhesion in the agricultural areas of the middle and lower reaches of the Yangtze River.

关键词： rice stubble field rotary tillage reducing soil adhesion staggered double-roller discrete element method

Optimal Operation Strategy of Electricity-Hydrogen Regional Energy System under Carbon-Electricity Market Trading

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Energy Engineering 2024年第3期121卷 619-641页

作者： Jingyu Li Mushui Wang Zhaoyuan Wu Guizhen Tian Na Zhang Guangchen liu Inner Mongolia Key Laboratory of Electrical Energy Conversion Transmission and Control Inner Mongolia University of TechnologyHohhot010080China School of Electric Power Inner Mongolia University of TechnologyHohhot010080China School of Electrical and Electronic Engineering North China Electric Power UniversityBeijing102206China

Given the“double carbon”objective and the drive toward low-carbon power,investigating the integration and interaction within the carbon-electricity market can enhance renewable energy utilization and facilitate energy conservation and emission reduction ***,further research is necessary to explore operational optimization methods for establishing a regional energy system using Power-to-Hydrogen(P2H)technology,focusing on participating in combined carbon-electricity market *** study introduces an innovative Electro-Hydrogen Regional Energy System(EHRES)in this *** system integrates renewable energy sources,a P2H system,cogeneration units,and energy storage *** core purpose of this integration is to optimize renewable energy utilization and minimize carbon *** study aims to formulate an optimal operational strategy for EHRES,enabling its dynamic engagement in carbon-electricity market *** initial phase entails establishing the technological framework of the electricity-hydrogen coupling system integrated with ***,an analysis is conducted to examine the operational mode of EHRES as it participates in carbon-electricity market ***,the system scheduling model includes a stepped carbon trading price mechanism,considering the combined heat and power generation characteristics of the Hydrogen Fuel Cell(HFC).This facilitates the establishment of an optimal operational model for EHRES,aiming to minimize the overall operating *** simulation example illustrates that the coordinated operation of EHRES in carbon-electricity market transactions holds the potential to improve renewable energy utilization and reduce the overall system *** result carries significant implications for attaining advantages in both low-carbon and economic aspects.

关键词： Regional energy system electro-hydrogen coupling carbon-electricity market step carbon trading coordination and optimization

Epidemiological Insights into Foodborne Pathogens Through qPCR Exploration of Prevalence—Beijing Municipality,China,January 2022-April 2023

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China CDC weekly 2024年第18期6卷 385-389,I0001-I0004页

作者： Penghang Zhang Xiaochen Ma Yuzhu liu Tongyu Wang Shuning Huo Xiaoai Zhang Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning Institute for Nutrition and Food HygieneBeijing Center for Disease Prevention and ControlBeijingChina Yanjing Medical College of Capital Medical University BeijingChina

Summary What is already known on this topic?Foodborne diseases present a substantial global health *** diagnostic methods have constraints,but advancements in molecular techniques,like quantitative polymerase chain reaction(qPCR),provide a hopeful *** is added by this report?We examined 1,011 stool samples from individuals suspected of foodborne illnesses.

关键词： solution constraints advancement

Optimization design and experiment of the variable differential gear train planting mechanism

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 85-93页

作者： Xiong Zhao Ziwei liu Yuanwu Jia Xingxiao Ma Pengfei Zhang Jianneng Chen School of Mechanical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China Xi’an International University Engineering College Xi’an 710077China Hangzhou Vocational&Technical College Hangzhou 310018China

In order to improve the adaptability of the planting mechanism for different plant spacings,a variable differential gear train planting mechanism based on precise pose and trajectory control was proposed by combining the open chain 2R rod group and the variable differential gear *** to the pose requirements of receiving seedling point,transporting seedling point and planting point,three precise pose points of constrained planting trajectory were *** the three-position motion generation structural synthesis method,combined with computer-aided optimization design software,a set of mechanism parameters that meet the planting requirements were *** on the optimized mechanism parameters,by only changing the coordinates of two trajectory shape control points,three planting trajectories with key point position information adapted to 300 mm,400 mm and 500 mm plant spacing were obtained by interpolation,and three pairs of total transmission ratio of three groups of variable differential gear trains were *** distributing the total transmission ratio of the mechanism,the fixed axis gear train and the differential gear train are *** fixed axis gear train included a pair of non-circular gear pairs and a pair of positive gear pairs,which were convenient for disassembly and *** former drives the sun gear at variable speed,and the latter drives the planet carrier at uniform *** on this structure,the transmission ratio of the positive gear pair is-1,and the transmission ratio of the differential gear train is *** sub-transmission ratio of the single-stage non-circular gear pair was calculated and the pitch curves of three pairs of noncircular gears were *** pairs of non-circular gear pairs with different transmission ratios were replaced in turn and three sets of planting mechanisms were modeled in three *** virtual prototype motion simulation was completed by ADAMS software,and the p

关键词： plant spacing planting mechanism variable differential gear train precise pose trajectory control parameter optimization

Relay C（sp）-H bond trifluoromethylthiolation and amidation by visible light photoredox catalysis

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Science China Chemistry 2024年

作者： Junheng liu Suqi Yang Shunruo Yao Chengjian Zhu Yong liu Weipeng Li Jin Xie State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials Chemistry and Biomedicine Innovation Center (ChemBIC) School of Chemistry and Chemical Engineering Nanjing University Green Catalysis Center College of Chemistry Zhengzhou University State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Nanjing Bready Advanced Materials Technology Co. Ltd. State Key Laboratory of Natural Medicines China Pharmaceutical University

Selective functionalization of C（sp3）–H bonds is a straightforward and practical method to construct complex molecule skeletons. In this field, direct transformation of unactivated C（sp3）–H bonds into C（sp3）–SCF3architectures is still a great *** report a highly selective trifluoromethylthiolation of unactivated aliphatic C（sp3）–H bonds by combination of proton-coupled electron transfer（PCET） and hydrogen atom transfer（HAT） strategy. A wide range of structurally diverse alkyl trifluoromethyl sulfides are obtained. Furthermore, the use of two different photocatalysts can realize an unprecedented trifluoromethylthiolation and amidation cascade of different C（sp3）–H bonds. It can afford a good access to bifunctionalized molecules in synthetically useful yields.

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基于Levy-GARCH模型的股票市场尾部风险度量研究

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中央财经大学学报 2024年第1期 47-60页

作者：朱福敏宋佳音刘仪榕深圳大学经济学院宁波诺丁汉大学

防范化解金融风险是牢牢守住不发生系统性风险底线的重要工作,描述资产价格规律、准确度量尾部风险是风险管理的前提。为研究非对称性和非高斯性对我国股市收益率预测和尾部风险度量的影响,本文使用20种Levy-GARCH模型对上证综合指数进... 详细信息

防范化解金融风险是牢牢守住不发生系统性风险底线的重要工作,描述资产价格规律、准确度量尾部风险是风险管理的前提。为研究非对称性和非高斯性对我国股市收益率预测和尾部风险度量的影响,本文使用20种Levy-GARCH模型对上证综合指数进行实证分析,计算噪声服从跳跃过程时的VaR和CVaR值,结合快速傅里叶变换数值计算和回溯测试进行检验。研究结果表明:在中国股市中,非高斯性和非对称性是不可忽视的重要特征,跳跃行为在收益率拟合、预测和风险度量方面有重要影响;在尾部风险度量上,带跳跃的非仿射结构条件方差模型表现稳定地优于仿射结构模型,而且有限跳跃过程模型的综合表现优于带无限活动率跳跃过程的模型。总的来说,非对称、非高斯、非仿射的Levy-GARCH模型在收益率拟合与尾部风险测度上表现更好,而且有限跳跃形态可以更准确地解释中国股票市场的尾部风险。

关键词：市场尾部风险 VaR 值 Levy-GARCH 模型有限跳跃非对称 GARCH

Study on Optimal Water ControlMethods for Horizontal Wells in Bottom Water Clastic Rock Reservoirs

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2377-2392页

作者： Xianghua liu Hai Song Lu Zhao Yan Zheng Neng Yang Dongling Qiu Sinopec Northwest Oilfield Branch Northwest Oilfield Branch of China Petroleum and Chemical CorporationUrumqi830011China School of Petroleum and Natural Gas Engineering Southwest Petroleum UniversityChengdu610500China

The segmented water control technology for bottom water reservoirs can effectively delay the entry of bottom water and adjust the production *** clarify the impact of different methods on horizontal well production with different reservoir conditions and to provide theoretical support for the scientific selection of methods for bottom water reservoirs,a numerical simulation method is presented in this study,which is able to deal with wellbore reservoir coupling under screen tube,perforation,and ICD(Inflow Control Device)*** the geological characteristics of the bottom-water conglomerate reservoir in the Triassic Formation of the Tahe Block 9 as a test case,the three aforementioned completion methods are tested to predict the transient production *** impact of completion parameters,reservoir permeability,bottom-water energy,and individual well control on the time to encounter water in horizontal wells(during a water-free production period)is discussed.A boundary chart for the selection of completion methods is introduced *** results show that the optimized ICD completion development effect for heterogeneous reservoirs is the best,followed by optimized perforation *** is the main factor affecting the performances of completion methods,while bottom water energy and single well controlled reserves have a scarce *** average permeability of the reservoir is less than 500 mD,and ICD has the best water control *** the permeability is greater than 500 mD,the water control effect of perforation completion becomes a better option.

关键词： Completion method bottom water low-permeability oil reservoir horizontal well development effect