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Concentration and speciation of arsenic in an insect feeding on the leaves of Pteris vittata

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Soil Ecology Letters 2021年第3期3卷 279-287页

作者： Xiaoming Wan Mei Lei Tongbin Chen Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100089China

The development of an effective and green bioinsecticide is a research hotspot.This study demonstrated the possibility of using an arsenic(As)hyperaccumulator as a bioinsecticide.When the As concentration in the Pteris vittata fronds exceeded 138 mg kg^(–1),the larva of the hawk moth(Theretra clotho)displayed apparent preference to lower-As-concentration P.vittata fronds.The As concentration in the larva body was as high as 850 mg kg^(–1).Such high concentration of As in the larva body might have been the case that T.clotho lacks a process to exclude As.The larval frass showed an As concentration of only 1%–4%of that in the larva body.The predominant As species in the larva body and frass was As(III)-SH.The percentage of As(III)-SH was slightly higher in the frass than that in the larval body.Chelation with thiols may be a universal detoxification mechanism for As in both plants and insects.In general,the adoption of P.vittata as a bioinsecticide should be feasible.However,the exact processes to achieve this goal still need further study.The mechanism of different animals to detoxify As is another interesting research topic.

关键词： Arsenic speciation Bioinsecticide Hawk moth Herbivore Hyperaccumulator

Global Spillovers of China's Monetary Policy

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China & World Economy 2024年第3期32卷 1-30页

作者： Wenni lei Dongzhou mei Mi Zhang School of Economics Minzu University of ChinaChina School of International Trade and Economics Central University of Finance and EconomicsChina

Spillovers from China's monetary policy have become increasingly obvious with China's growing importance in the global economy and its close economic and trade ties with the world.This study establishes a proxy structure vector autoregression model to investigate the magnitude and transmission channel of spillovers from China to global and regional economies,taking advantage of high-frequency changes in asset prices in the financial markets to identify monetary policy shocks.The analysis reveals that China's monetary policy can affect the global economy by influencing international trade and commodity prices but there is no evidence of China's monetary policy affecting global financial variables.Tightness in China's monetary policy can cause a decline in world output whereas expansion in monetary policy can support global trade and output.This study also finds that the response of emerging Asian economies to China's monetary policy shock was nearly twice that of developed economies,while the transmission path did not change.The results of this study are consistent with the stylized fact that China's monetary policy plays an important role in the global trade and commodity cycle,although it does not drive the global financial cycle.

关键词： China's monetary policy commodity prices external instruments global trade spillovers

Molecular Generation and Optimization of Molecular Properties Using a Transformer Model

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Big Data Mining and Analytics 2024年第1期7卷 142-155页

作者： Zhongyin Xu Xiujuan lei mei Ma Yi Pan School of Computer Science Shaanxi Normal UniversityXi'an 710119China Faculty of Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Generating novel molecules to satisfy specific properties is a challenging task in modern drug discovery,which requires the optimization of a specific objective based on satisfying chemical rules.Herein,we aim to optimize the properties of a specific molecule to satisfy the specific properties of the generated molecule.The Matched Molecular Pairs(MMPs),which contain the source and target molecules,are used herein,and logD and solubility are selected as the optimization properties.The main innovative work lies in the calculation related to a specific transformer from the perspective of a matrix dimension.Threshold intervals and state changes are then used to encode logD and solubility for subsequent tests.During the experiments,we screen the data based on the proportion of heavy atoms to all atoms in the groups and select 12365,1503,and 1570 MMPs as the training,validation,and test sets,respectively.Transformer models are compared with the baseline models with respect to their abilities to generate molecules with specific properties.Results show that the transformer model can accurately optimize the source molecules to satisfy specific properties.

关键词： molecular optimization transformer Matched Molecular Pairs(MMPs) logD solubility

Spatial prediction of soil contamination based on machine learning: a review

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环境科学与工程前沿(英文) 2023年第8期17卷 13-29页

作者： Yang Zhang Mei Lei Kai Li Tienan Ju Institute of Geographic Sciences&Natural Resources Research Chinese Academy of SciencesBeijing 100101China Sino-Danish College University of Chinese Academy of SciencesBeijing 100190China

Soil pollution levels can be quantified via sampling and experimental analysis;however,sampling is performed at discrete points with long distances owing to limited funding and human resources,and is insufficient to characterize the entire study area.Spatial prediction is required to comprehensively investigate potentially contaminated areas.Consequently,machine learning models that can simulate complex nonlinear relationships between a variety of environmental conditions and soil contamination have recently become popular tools for predicting soil pollution.The characteristics,advantages,and applications of machine learning models used to predict soil pollution are reviewed in this study.Satisfactory model performance generally requires the following:1)selection of the most appropriate model with the required structure;2)selection of appropriate independent variables related to pollutant sources and pathways to improve model interpretability;3)improvement of model reliability through comprehensive model evaluation;and 4)integration of geostatistics with the machine learning model.With the enrichment of environmental data and development of algorithms,machine learning will become a powerful tool for predicting the spatial distribution and identifying sources of soil contamination in the future.

关键词： Soil contamination Machine learning Prediction Spatial distribution

Structural and magnetic properties of micropolycrystalline cobalt thin films fabricated by direct current magnetron sputtering

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 384-394页

作者： Kerui Song Zhou Li mei Fang Zhu Xiao Qian lei School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics and electronicsCentral South UniversityChangsha 410083China Key Laboratory of Non-Ferrous Metal Materials Science and Engineering Ministry of EducationChangsha 410083China

Pure cobalt(Co)thin films were fabricated by direct current magnetron sputtering,and the effects of sputtering power and pres-sure on the microstructure and electromagnetic properties of the films were investigated.As the sputtering power increases from 15 to 60 W,the Co thin films transition from an amorphous to a polycrystalline state,accompanied by an increase in the intercrystal pore width.Simultaneously,the resistivity decreases from 276 to 99μΩ·cm,coercivity increases from 162 to 293 Oe,and in-plane magnetic aniso-tropy disappears.As the sputtering pressure decreases from 1.6 to 0.2 Pa,grain size significantly increases,resistivity significantly de-creases,and the coercivity significantly increases(from 67 to 280 Oe),which can be attributed to the increase in defect width.Corres-pondingly,a quantitative model for the coercivity of Co thin films was formulated.The polycrystalline films sputtered under pressures of 0.2 and 0.4 Pa exhibit significant in-plane magnetic anisotropy,which is primarily attributable to increased microstress.

关键词： cobalt thin film magnetron sputtering microstructure electromagnetic properties

An efficient 3D cell-based discrete fracture-matrix flow model for digitally captured fracture networks

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International Journal of Coal Science & Technology 2023年第5期10卷 87-106页

作者： lei Sun mei Li Aly Abdelaziz Xuhai Tang Quansheng Liu Giovanni Grasselli Department of Civil and Mineral Engineering University of TorontoTorontoON M5S 1A4Canada School of Civil Engineering Wuhan UniversityWuhan 430072China

Complex hydraulic fracture networks are critical for enhancing permeability in unconventional reservoirs and mining indus-tries.However,accurately simulating the fluid flow in realistic fracture networks(compared to the statistical fracture net-works)is still challenging due to the fracture complexity and computational burden.This work proposes a simple yet efficient numerical framework for the flow simulation in fractured porous media obtained by 3D high-resolution images,aiming at both computational accuracy and efficiency.The fractured rock with complex fracture geometries is numerically constructed with a cell-based discrete fracture-matrix model(DFM)having implicit fracture apertures.The flow in the complex fractured porous media(including matrix flow,fracture flow,as well as exchange flow)is simulated with a pipe-based cell-centered finite volume method.The performance of this model is validated against analytical/numerical solutions.Then a lab-scale true triaxial hydraulically fractured shale sample is reconstructed,and the fluid flow in this realistic fracture network is simu-lated.Results suggest that the proposed method achieves a good balance between computational efficiency and accuracy.The complex fracture networks control the fluid flow process,and the opened natural fractures behave as primary fuid pathways.Heterogeneous and anisotropic features of fluid flow are well captured with the present model.

关键词： Fractured porous medium-Flow simulation Digital image Cell-based DFM Finite volume method

A sustained-release microcarrier effectively prolongs and enhances the antibacterial activity of lysozyme

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Journal of Environmental Sciences 2023年第7期129卷 128-138页

作者： mei Du Jingzhang Liu Fengbang Wang lei Bi Chunyan Ma Maoyong Song Guibin Jiang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of ScienceBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Bacterial infections have become a great threat to public health in recent years.A primary lysozyme is a natural antimicrobial protein;however,its widespread application is limited by its instability.Here,we present a poly(N-isopropylacrylamide)hydrogel inverse opal particle(PHIOP)as a microcarrier of lysozyme to prolong and enhance the efficiency against bacteria.This PHIOP-based lysozyme(PHIOP-Lys)formulation is temperature-responsive and exhibits long-term sustained release of lysozyme for up to 16 days.It shows a potent antibacterial effect toward both Escherichia coli and Staphylococcus aureus,which is even higher than that of free lysozyme in solution at the same concentration.PHIOPs-Lys were demonstrated to effectively inhibit bacterial infections and enhance wound healing in a full-thickness skin wound rat model.This study provides a novel pathway for prolonging the enzymatic activity and antibacterial effects of lysozyme.

关键词： Bacterial infection Lysozyme Temperature-responsive Inverse opal particle Wound healing

Characterizing ship-induced hydrodynamics in a heavy shipping traffic waterway via intensified field measurements

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Water Science and Engineering 2020年第4期13卷 329-338页

作者： Li-lei Mao Yi-mei Chen Xin Li Department of Port Waterway and Coastal EngineeringSoutheast UniversityNanjing 211189China

Ship-induced hydrodynamics play an important role in shaping the cross-sectional profile of inland waterways and produce a large amount of pressure on the fluvial environment.This study aimed at quantifying the characteristics of ship-induced waves and currents in a heavy shipping traffic waterway via intensified field measurements conducted in the Changzhou segment of the Grand Canal,in Jiangsu Province,China.Based on the processed hydrodynamic data,waves and currents caused by single ships and multiple ships were investigated.For single ships,the shipinduced wave heights estimated with empirical formulas were not consistent with the observations.Categorized by the loading conditions of barges,the drawdown height was characterized by the ratio of ship speed to its limit speed.The maximum non-dimensional ship-induced wave height was parameterized by a nonlinear combination of the depth Froude number and a blockage coefficient.For multiple ships,when ships closely followed each other or interlaced each other's paths,it was difficult to characterize the superposition of several ship wakes.The magnitudes of current velocities induced by single ships and multiple ships were respectively nine and six times as large as those of natural flow.This may result in more severe sediment(re)suspension than natural flows.©2020 Hohai University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Ship-induced waves Drawdown Field measurements Current velocity Sediment(re)suspension Grand Canal

Development of a model to simulate soil heavy metals lateral migration quantity based on SWAT in Huanjiang watershed,China

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Journal of Environmental Sciences 2019年第3期31卷 115-129页

作者： Pengwei Qiao Mei Lei Sucai Yang Jun Yang Xiaoyong Zhou Nan Dong Guanghui Guo Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing Key Laboratory of Remediation of Industrial Pollution Sites Environmental Protection Research Institute of Light Industry Comprehensive Institute of Geotechnical Investigation and Surveying Ltd.

Lateral transportation of soil heavy metals in rainfall events could significantly increase the scope of pollution. Therefore, it is necessary to develop a model with high accuracy to simulate the migration quantity of heavy metals. A model for heavy metal migration simulation was developed based on the SWAT(Soil and Water Assessment Tool) model. This model took into consideration the influence of soil p H value, soil particle size, runoff volume, sediment amount,concentration of water-soluble heavy metals dissolved in runoff and insoluble absorbed to the soil particles. This model was reasonable in Huanjiang watershed, Guangxi Zhuang Autonomous Region, south China, covering an area of 273 km^2. The optimal drainage area threshold was determined by analyzing the effects of watershed subdivision on the simulation results to ensure the simulation accuracy. The main conclusions of this paper were:(1) watershed subdivision could affect simulation migration quantity of heavy metals;(2) the quantity of heavy metals transported by sediment accounted for 97%–99% of the total migration quantity in the study watershed. Therefore, sediment played the most important role in heavy metal migration;(3) the optimal drainage area threshold percentage to ensure high simulation accuracy was determined to be 2.01% of the total watershed;(4) with the optimal threshold percentage, this model could simulate the migration quantity of As, Pb and Cd accurately at the total watershed and subwatershed level. The results of this paper were useful for identifying the key regions with heavy metal migration.

关键词： Soil heavy metal migration Simulation model Watershed subdivision Optimal drainage area threshold percentage Simulation accuracy