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Biofiltration and disinfection codetermine the bacterial antibiotic resistome in drinking water:A review and meta-analysis

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Frontiers of Environmental Science & Engineering 2020年第1期14卷 23-34页

作者： kun wan Wenfang Lin Shuai Zhu Shenghua Zhang Xin Yu Key Laboratory of Urban Environment and Health.Institute of Urban Environment Chinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Beijing Guohuan Tsinghua Environmental Engineering Design&Research Institute Co. Ltd.Beijing 100084China

The bacterial antibiotic resistome(BAR)is one of the most serious contemporary medical *** BAR problem in drinking water is receiving growing *** this study,we focused on the distribution,changes,and health risks of the BAR throughout the drinking water treatment *** extracted the antibiotic resistance gene(ARG)data from recent publications and analyzed ARG profiles based on diversity,absolute abundance,and relative *** absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA(r=0.963,/?<0.001),indicating that the reduction of ARG concentration was accompanied by decreasing *** treatment processes,biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic *** exhibited positive effects in controlling the diversity of ARG,while biofiltration,especially granular activated carbon filtration,increased the diversity of *** biofiltration and chlorination altered the structure of the resistome by affecting relative ARG *** addition,we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic *** intercepting influent ARG-carrying bacteria,biofilters can enrich various ARGs and maintain ARGs in *** further selects bacteria co-resistant to chlorine and ***,we proposed the BAR health risks caused by biofiltration and chlorination in water *** reduce potential BAR risk in drinking water,membrane filtration technology and water boiling are recommended at the point of use.

关键词： Drinking water treatment Antibiotic resistance gene Biofiltration Chlorination

Application of Lattice Boltzmann Method to Simulate Forest Edge

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Advances in Applied Mathematics and Mechanics 2023年第2期15卷 376-401页

作者： Jie Wei Jianjun Wu An Jiang kun wan Key Laboratory of Mechanics on Disaster and Environment inWestern China Attached to the Ministry of Education of ChinaLanzhou UniversityLanzhouGansu 730000China College of Civil Engineering and Mechanics Lanzhou UniversityLanzhouGansu 730000China Shenzhen TenFong Technology Co. LtdGuangdongChina ZhongJiao TianHe Machinery Equipment Manufacturing Co.LTD SuzhouJiangsuChina

This study is focused on the forest edge flow by using numerical *** model the effects of a forest canopy on airflow,source terms are introduced into the governing *** lattice Boltzmann method in conjunction with the standard k-εmodel is applied to solve the turbulent wind *** order to perform the simulation on non-uniform grids,the Taylor series expansion and least square based lattice Boltzmann method(TLLBM)is adopted to improve the accuracy and computational *** present method and code are verified with an earlier forest edge simulation.A series of forest canopies are established to explore the impacts of canopy morphology on wind *** canopies cover 3 canopy architectures and the Leaf Area Index(LAI)ranges from 2.0 to *** further study is carried out by adjusting the canopy foliage amount and the canopy *** present study demonstrates the potential of lattice Boltzmann method to simulate the high Re number forest edge *** impacts of canopy morphology on zero plane displacement,aerodynamic roughness length,friction wind velocity,permeability coefficient,wall-shear stress are illustrated in *** results show that the canopy sub-layer wind field,especially the wind velocity profiles within and above the forest canopy,are mainly determined by canopy morphology.

关键词： Forest edge lattice Boltzmann method non-uniform grids canopy morphology

Potential shift of bacterial community structure and corrosion-related bacteria in drinking water distribution pipeline driven by water source switching

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Frontiers of Environmental Science & Engineering 2021年第2期15卷 117-126页

作者： Yue Hu Ding Dong kun wan Chao Chen Xin Yu Huirong Lin Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Research Institute for Environmental Innovation(Suzhou) TsinghuaSuzhou 215163China College of Environment&Ecology Xiamen UniversityXiamen 361102China School of Environment Tsinghua UniversityBeijing 100084China Department of Environmental Science and Engineering College of Chemical EngineeringHuaqiao UniversityXiamen 361021China

As a result of pollution in the present water sources,cities have been forced to utilize cleaner water *** are few reports regarding the potential shift of bacterial community structure driven by water source switching,especially that of corrosion-related *** types of finished water were used for simulation,the polluted source water from the Qiantang and Dongtiaoxi Rivers(China)was replaced by cleaner water from Qiandao Lake(China).Here,we discussed the transition effects through three simulated *** bacterial characteristics were identified using the highthroughput sequencing and heterotrophic plate count *** was observed that the level of culturable bacteria declined by 2–3 orders of magnitude after water source *** bacterial community released from the pipeline reactor was significantly different under different finished water,and it exhibited large variation at the genus ***(58.2%)and Phreatobacter(14.5%)clearly replaced Novosphingobium,Aquabacterium,and Cupriavidus as new dominant genera in system A,which could be attributed to the lower carbon and nitrogen content of the new water *** corrosion-inhibiting bacteria decreased after switching,they still maintained dominant in three reactors(6.6%,15.9%,and 19.7%).Furthermore,potential opportunistic pathogens such as Sphingomonas were *** study shows that after transition to a high quality water source,the total culturable bacteria released was in a downtrend,which leads to a great reduction in the risk of bacterial leakage in the produced drinking water.

关键词： Drinking water biosafety Water source switching Drinking water distribution system Transition effects High-throughput sequencing

Low nutrient levels as drinking water conditions can reduce the fitness cost of efflux pump-mediated ciprofloxacin resistance in Pseudomonas aeruginosa

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Journal of Environmental Sciences 2019年第9期31卷 123-132页

作者： Wenfang Lin kun wan Jie Zeng Jingjing Li Xi Li Xin Yu Key Lab of Urban Environment and Health Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China University of Chinese Academy of Sciences Beijing 100049 China

The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usually confers a fitness cost in bacteria. In this study, we aimed to determine why antibiotic resistance conferred by overexpression of an efflux pump persisted in low-nutrient environments(TOC < 10 mg/L) such as drinking and source water in which antibiotic selective pressure might be very low or even *** experiments between wild-type Pseudomonas aeruginosa and ciprofloxacinresistant mutants revealed that the fitness cost of ciprofloxacin resistance significantly decreased(p < 0.05) under low-nutrient(0.5 mg/L total organic carbon(TOC)) relative to high-nutrient(500 mg/L TOC) conditions. Mechanisms underlying this fitness cost were analyzed. The mexD gene expression in resistant bacteria(cip3 strain) was significantly lower(p < 0.05) in low-nutrient conditions, with 10 mg/L TOC((8.01 ± 0.82)-fold), than in high-nutrient conditions, with 500 mg/L TOC((48.89 ± 4.16)-fold). Moreover, rpoS gene expression in resistant bacteria((1.36 ± 0.13)-fold) was significantly lower(p < 0.05) than that in the wild-type strain((2.78 ± 0.29)-fold) under low-nutrient conditions(10 mg/L TOC),suggesting a growth advantage. Furthermore, the difference in metabolic activity between the two competing strains was significantly smaller(p < 0.05) in low-nutrient conditions(5 and 0.5 mg/L TOC). These results suggest that nutrient levels are a key factor in determining the persistence of antibiotic resistance conferred by efflux pumps in the natural environment with trace amounts or no antibiotics.

关键词： Efflux pumps Antibiotic resistance Fitness cost Low nutrient nfxB mutation Ciprofloxacin resistance

Adsorption of Au(Ⅲ) by amino-modified monodispersed PGMA microspheres and deposition of gold nanoparticles

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Rare Metals 2018年第3期37卷 196-203页

作者： Fu-Chun wang Jun-Mei Zhao wan-kun wang Zi-Zheng Tong School of Materials and Metallurgical Engineering Guizhou Institute of Technology Institute of Process Engineering Chinese Academy of Sciences

Monodispersed poly（glycidyl methacrylate）（PGMA） microspheres with various amounts of amino groups（PGMA-NH2） were used to adsorb Au（Ⅲ） from simulated wastewaters. Gold nanoparticle-coated PGMA functional microspheres can be directly obtained via the adsorption process. The adsorption kinetics follows pseudo-second model, and 10 min is enough for reaching at equilibrium. The adsorption isotherm follows Langmuir model, and the adsorption amounts for Au（Ⅲ） are 8.25 and 21.75 mol·kg^-1 at 298 and 328 K, respectively. The relative separation coefficients between Au（Ⅲ）, Pt（Ⅵ）, Pd（Ⅱ）and Co（Ⅱ）, Cu（Ⅱ）; Ni（Ⅱ）, Fe（Ⅲ） are all higher than 100 when 1 〈 pH 〈 3. Furthermore, the characterization analysis of X-ray diffraction（XRD）, thermogravimetrydifferential scanning calorimetry（TG-DSC）, scanning electron microscopy-energy dispersive spectroscopy（SEM-EDS）, transmission electron microscopy（TEM） and Fourier transform infrared spectroscopy（FTIR） confirms that AuCl4^-has been reduced to Au^0 nanoparticles and deposited onto the surface of PGMA-NH2. The current work shows a good prospect for PGMA-NH2 to be a valid adsorbent for the recovery of gold and the possible fabrication of gold nanoparticles by reduction-deposition process without any reductant.

关键词： PGMA microspheres AuCl4^- Amino groups Adsorption Reduction-deposition Elemental gold

Urchin-like Nb_(2)O_(5)hollow microspheres enabling efficient and selective photocatalytic C–C bond cleavage in lignin models under ambient conditions

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Chinese Chemical Letters 2022年第9期33卷 4357-4362页

作者： Huan Chen Donghui Hong kun wan Junjie wang Bo Niu Yayun Zhang Donghui Long State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Multiphase Materials Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Selective cleavage of robust C−C bonds to harvest value-added aromatic oxygenates is an intriguing but challenging task in lignin *** is a promising technology with the advantages of mild reaction conditions and strong ***,we show a novel urchin-like Nb_(2)O_(5)hollow microsphere(U-Nb_(2)O_(5)HM),prepared by one-pot hydrothermal method,are highly active and selective for C_(α)−C_(β)bond cleavage of ligninβ-O-4 model compounds under mild conditions,achieving 94%substrate conversion and 96%C−C bond cleavage *** experimental studies and density functional theory(DFT)calculations revealed that the superior performance of U-Nb_(2)O_(5)HMs arises from more exposed active sites,more efficient free charge separation and the active(001)facet,which facilitates the activation of Cβ−H bond of lignin models and generate key Cβradical intermediates by photogenerated holes,further inducing the C_(α)−C_(β)bond cleavage to produce aromatic *** work could provide some suggestions for the fabrication of hierarchical photocatalysts in the lignin depolymerization system.

关键词： Niobium oxide Urchin-like hierarchical structure Photocatalysis β-O-4 Lignin model C_(β)radical

Cumulative damage effect on debris slopes under frequent microseisms

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Journal of Mountain Science 2022年第3期19卷 781-797页

作者： YANG Zhong-ping LI Shi-qi TIAN Xin HU Yuan-xin LI wan-kun School of Civil Engineering Chongqing UniversityChongqing 400045China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area(Chongqing) Chongqing 400045China Southwest Institute of Chemical Co. Ltd.Chengdu 610200China Extension Project Headquarters of Chongqing Jiangbei International Airport Chongqing 401120China Chongqing Luneng Development(Group)Co. Ltd.Chongqing 401120China

Debris slopes are widely distributed across the Three Gorges Reservoir area in China,and seasonal fluctuations of the water level in the area tend to cause high-frequency microseisms that subsequently induce landslides on such debris *** this study,a cumulative damage model of debris slope with varying slope characteristics under the effects of frequent microseisms was established,based on the accurate definition of slope damage *** cumulative damage behaviour and the mechanisms of slope instability and sliding under frequent microseisms were thus systematically investigated through a series of shaking table tests and discrete element numerical simulations,and the influences of related parameters such as bedrock,dry density and stone content were *** results showed that the instability mode of a debris slope can be divided into a vibration-compaction stage,a crack generation stage,a crack development stage,and an instability *** the action of frequent microseisms,debris slope undergoes the last three stages cyclically,which causes the accumulation to slide out in layers under the synergistic action of tension and shear,causing the slope to become *** are two sliding surfaces as well as the parallel tensile surfaces in the final instability of the debris *** the process of instability,the development trend of the damage accumulation curve remains similar for debris slopes with different ***,the initial vibration compaction effect in the bedrock-free model is stronger than that in the bedrock model,with the overall cumulative damage degree in the former being lower than that of the *** damage degree of the debris slope with high dry density also develops more slowly than that of the debris slope with low dry *** damage development rate of the debris slope does not always decrease with the increase of stone *** damage degree growth rate of the debris slope with the optimal stone

关键词： Cumulative damage Debris slopes Frequent microseisms Shaking table tests Discrete element numerical simulation

An Overview of Double JPEG Compression Detection and Anti-detection

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Journal of Information Hiding and Privacy Protection 2022年第2期4卷 89-101页

作者： kun wan Nanjing University of Information Science and Technology Nanjing210044China

JPEG(Joint Image Experts Group)is currently the most widely used image format on the *** cases show that many tampering operations occur on JPEG *** basic process of the operation is that the JPEG file is first decompressed,modified in the null field,and then the tampered image is compressed and saved in JPEG format,so that the tampered image may be compressed several ***,the double compression detection of JPEG images can be an important part for determining whether an image has been tampered with,and the study of double JPEG compression anti-detection can further advance the progress of detection *** this paper,we mainly review the literature in the field of double JPEG compression detection in recent years with two aspects,namely,the quantization table remains unchanged and the quantization table is inconsistent in the double JPEG compression process,Also,we will introduce some representative methods of double JPEG anti-detection in recent ***,we analyze the problems existing in the field of double JPEG compression and give an outlook on the future development direction.

关键词： Double JPEG compression detection and anti-detection image processing

Strategies for Improving Street Vitality Guided by Building a Sense of Community Identity

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Journal of Landscape Research 2020年第6期12卷 98-100页

作者： wan kun College of City Construction Jiangxi Normal UniversityNanchangJiangxi 330022China

In the continuous growth process of urbanization level in China,the community is gradually divided,and the urban vitality is gradually *** the community management mode of grass-roots autonomy,cultivation of community identity is conducive to creating an unique community culture,making the whole community more united and cohesive,moulding a relaxed and pleasant community atmosphere,thereby enhancing the vitality of the *** identity also provides a new perspective for the study of the relationship between people and street *** this paper,the influence of community identity on the spatial vitality of urban street is discussed,and the corresponding improvement measures are put forward.

关键词： Sense of community identity Street space Vitality