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Transport of antibiotic resistance plasmids in porous media and the influence of surfactants

Peipei Chen, Chaoqi Chen, Xiqing Li

《环境科学与工程前沿（英文）》 2018年 第12卷 第2期 doi: 10.1007/s11783-017-0986-7

摘要： Transport of engineered antibiotic resistance plasmids in porous media has been reported to potentially cause significant spreading of antibiotic resistance in the environment. In this work, transport of an indigenous resistance plasmid pK5 in porous media was investigated through packed column experiments. At identical ionic strengths in CaCl solutions, the breakthroughs of pK5 from soil columns were very close to those from quartz sand columns, indicating that transport of pK5 in quartz sand and soil was similar. A similarity in transport behavior was also found between pK5 and an engineered plasmid pBR322 that has approximately the same number of base pairs as pK5. The influence of surfactants, a major group of constituents in soil solutions, was examined using an engineered plasmid pcDNA3.1(+)/myc-His A. The impact of an anionic surfactant, sodium dodecyl sulfate (SDS), was negligible at concentrations up to 200 mg·L . Cetyltrimethyl ammonium bromide (CTAB), a cationic surfactant, was found to significantly enhance plasmid adsorption at high concentrations. However, at environmentally relevant concentrations (<1 mg·L ), the effect of this surfactant was also minimal. The negligible impact of surfactants and the similarity between the transport of engineered and indigenous plasmids indicate that under environmentally relevant conditions, indigenous plasmids in soil also have the potential to transport over long distances and lead to the spreading of antibiotic resistance.

关键词： Indigenous plasmid     Transport     Porous media     Surfactants    

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Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 114-120 doi: 10.1007/s11709-014-0267-5

摘要： The accurate and efficient simulation of random heterogeneous media is important in the framework of modeling and design of complex materials across multiple length scales. It is usually assumed that the morphology of a random microstructure can be described as a non-Gaussian random field that is completely defined by its multivariate distribution. A particular kind of non-Gaussian random fields with great practical importance is that of translation fields resulting from a simple memory-less transformation of an underlying Gaussian field with known second-order statistics. This paper provides a critical examination of existing random field models of heterogeneous two-phase media with emphasis on level-cut random fields which are a special case of translation fields. The case of random level sets, often used to represent the geometry of physical systems, is also examined. Two numerical examples are provided to illustrate the basic features of the different approaches.

关键词： microstructure     random fields     level sets     shape recovery     two-phase media    

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Social media and mobility landscape: Uncovering spatial patterns of urban human mobility with multi source

Yilan Cui, Xing Xie, Yi Liu

《环境科学与工程前沿（英文）》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1068-1

摘要：

Check-in and survey data are explored to identify personal activity-specific places.

Ways for detecting and moderating sample bias of Weibo check-in data is proposed.

A graphic representation of urban activity intensity in Beijing, China is presented.

The potential application of Weibo check-in data for urban analysis is introduced.

关键词： Social media     Human mobility     Population bias     Sample reconstruction     Data integration    

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Immunogenicity and protective immunity against otitis media caused by pneumococcus in mice of Hib conjugate

null

《医学前沿（英文）》 2016年 第10卷 第4期   页码 490-498 doi: 10.1007/s11684-016-0470-y

摘要：

This study evaluated the immunogenicity and protective immunity of a Hemophilus influenzae b (Hib) polysaccharide conjugate vaccine with the pneumococcal surface adhesin A (PsaA) protein carrier in young mice. The Hib polysaccharide was conjugated with the rPsaA protein carrier, which was produced using recombinant DNA technology. A total of 15 young mice aged 3 weeks to 5 weeks were immunized with the conjugate vaccine, and another 15 young mice of the same age were immunized with the licensed Hib-tetanus toxoid (TT) vaccine. Furthermore, the third group of 15 young mice was inoculated with phosphate buffer saline as control. The immunized mice were inoculated with pneumococcus in the middle ear. Results showed that IgG antibody responses against both the PsaA protein and Hib polysaccharide were observed in the Hib-PsaA group. However, no statistical difference was observed in the titer of IgG against the Hib polysaccharide between Hib-PsaA and Hib-TT groups. The elimination rate of pneumococcus and the inflammation of the middle ear showed the effectiveness of protective immunity against otitis media caused by pneumococcus. Our results suggest that the Hib polysaccharide can be successfully conjugated with rPsaA via amide condensation. This new Hib-PsaA conjugate vaccine can induce both anti-PsaA and anti-Hib immune responses in young mice and elicit effective protection against acute otitis media caused by pneumococcus.

关键词： conjugate vaccine     pneumococcal surface adhesin A     Hemophilus influenzae b     immunogenicity     otitis media    

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analysis and seepage process study on crystal layer in melt crystallization with fractal and porous media

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 435-441 doi: 10.1007/s11705-011-1139-3

摘要： In this paper a porous media seepage model was applied to analyze the permeability and study the seepage process of crystal pillar formed in the preparation of electronic grade phosphoric acid (EGPA). By inspecting the seeping process, the structure parameter of crystal pillar could be obtained. Two basic ideal models (perfectly separated model and perfectly connected model) were presented and a characterized factor was introduced to modify the model. A good simulation result was obtained which met the experiment result well. The relationship between and permeability were also discussed. The characterized factor showed potential application on optimizing process.

关键词： melt crystallization     porous media     fractal     permeability     hyperpure material     simulation    

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Analytical solutions of three-dimensional contaminant transport in uniform flow field in porous media

Hongtao WANG, Huayong WU

《环境科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 112-128 doi: 10.1007/s11783-008-0067-z

摘要： The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay, linear sorption, and zero-order production. The library is constructed using Green's function method (GFM) in combination with available solutions. The library covers a wide range of solutions for various conditions. The aquifer can be vertically finite, semi-infinitive or infinitive, and laterally semi-infinitive or infinitive. The geometry of the sources can be of point, line, plane or volumetric body; and the source release can be continuous, instantaneous, or by following a given function over time. Dimensionless forms of the solutions are also proposed. A computer code FlowCAS is developed to calculate the solutions. Calculated results demonstrate the correctness of the presented solutions. The library is widely applicable to solve contaminant transport problems of one- or multiple- dimensions in uniform flow fields.

关键词： solution library     contaminant transport     analytical solution     dispersion and advection     porous media     type curve     Green's function method (GFM)    

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Migration and fate of polycyclic aromatic hydrocarbons in bioretention systems with different media:

《环境科学与工程前沿（英文）》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1802-9

摘要：

● Bioretention systems showed > 92% load reduction rates of PAHs.

关键词： Bioretention     Polycyclic aromatic hydrocarbons     HYDRUS-1D     Model simulation     Migration    

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The influence of social media on stock volatility

Xianjiao WU, Xiaolin WANG, Shudong MA, Qiang YE

《工程管理前沿（英文）》 2017年 第4卷 第2期   页码 201-211 doi: 10.15302/J-FEM-2017018

摘要： This study explores the influence of social media on stock volatility and builds a feature model with an intelligence algorithm using social media data from Xueqiu.com in China, Sina Finance and Economics, Sina Microblog, and Oriental Fortune. We find that the effect of social factors, such as increased attention to a stock’s volatility, is more significant than public sentiment. A prediction model is introduced based on social factors and public sentiment to predict stock volatility. Our findings indicate that the influence of social media data on the next day’s volatility is more significant but declines over time.

关键词： stock volatility     social data     sentiment analysis     boosting algorithm    

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Investigation of Generalized SIFs of cracks in 3D piezoelectric media under various crack-face conditions

Jaroon RUNGAMORNRAT, Bounsana CHANSAVANG, Weeraporn PHONGTINNABOOT, Chung Nguyen VAN

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 280-298 doi: 10.1007/s11709-019-0586-7

摘要： This paper investigates the influence of crack geometry, crack-face and loading conditions, and the permittivity of a medium inside the crack gap on intensity factors of planar and non-planar cracks in linear piezoelectric media. A weakly singular boundary integral equation method together with the near-front approximation is adopted to accurately determine the intensity factors. Obtained results indicate that the non-flat crack surface, the electric field, and the permittivity of a medium inside the crack gap play a crucial role on the behavior of intensity factors. The mode-I stress intensity factors ( ) for two representative non-planar cracks under different crack-face conditions are found significantly different and they possess both upper and lower bounds. In addition, for impermeable and semi-permeable non-planar cracks treated depends strongly on the electric field whereas those of impermeable, permeable, and semi-permeable penny-shaped cracks are identical and independent of the electric field. The stress/electric intensity factors predicted by permeable and energetically consistent models are, respectively, independent of and dependent on the electric field for the penny-shaped crack and the two representative non-planar cracks. Also, the permittivity of a medium inside the crack gap strongly affects the intensity factors for all crack configurations considered except for of the semi-permeable penny-shaped crack.

关键词： crack-face conditions     intensity factors     non-flat cracks     permittivity     piezoelectric media     SGBEM    

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An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous media

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 914-936 doi: 10.1007/s11709-021-0750-8

摘要： Crack growth modeling has always been one of the major challenges in fracture mechanics. Among all numerical methods, the extended finite element method (XFEM) has recently attracted much attention due to its ability to estimate the discontinuous deformation field. However, XFEM modeling does not directly lead to reliable results, and choosing a strategy of implementation is inevitable, especially in porous media. In this study, two prevalent XFEM strategies are evaluated: a) applying reduced Young’s modulus to pores and b) using different partitions to the model and enriching each part individually. We mention the advantages and limitations of each strategy via both analytical and experimental validations. Finally, the crack growth is modeled in a natural porous media (Fontainebleau sandstone). Our investigations proved that although both strategies can identically predict the stress distribution in the sample, the first strategy simulates only the initial crack propagation, while the second strategy could model multiple cracks growths. Both strategies are reliable and highly accurate in calculating the stress intensity factor, but the second strategy can compute a more reliable reaction force. Experimental tests showed that the second strategy is a more accurate strategy in predicting the preferred crack growth path and determining the maximum strength of the sample.

关键词： numerical modeling     extended finite element method     porous media     crack growth     stress intensity factor    

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An efficient stochastic dynamic analysis of soil media using radial basis function artificial neural

P. ZAKIAN

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 470-479 doi: 10.1007/s11709-017-0440-8

摘要： Since a lot of engineering problems are along with uncertain parameters, stochastic methods are of great importance for incorporating random nature of a system property or random nature of a system input. In this study, the stochastic dynamic analysis of soil mass is performed by finite element method in the frequency domain. Two methods are used for stochastic analysis of soil media which are spectral decomposition and Monte Carlo methods. Shear modulus of soil is considered as a random field and the seismic excitation is also imposed as a random process. In this research, artificial neural network is proposed and added to Monte Carlo method for sake of reducing computational effort of the random analysis. Then, the effects of the proposed artificial neural network are illustrated on decreasing computational time of Monte Carlo simulations in comparison with standard Monte Carlo and spectral decomposition methods. Numerical verifications are provided to indicate capabilities, accuracy and efficiency of the proposed strategy compared to the other techniques.

关键词： stochastic analysis     random seismic excitation     finite element method     artificial neural network     frequency domain analysis     Monte Carlo simulation    

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Scientifically advanced woody media for improved water quality from livestock woodchip heavy-use areas

Laura Christianson, David DeVallance, Joshua Faulkner, Thomas Basden

《环境科学与工程前沿（英文）》 2017年 第11卷 第3期 doi: 10.1007/s11783-017-0909-7

摘要： Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use of a woodchip heavy-use area (HUA) presents advantages such as a soft, supportive, and dry foot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of: 1) six types of wood media (including torrefied wood media and biochar) that could be used in a woodchip HUA versus a gravel control, and 2) providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events (53%–61% vs. 39% reductions, respectively), and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments (mean removal efficiencies>50%) was observed across the simulated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon (i.e., fresh woodchips exhibited>70% nitrate removal). The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.

关键词： Overwinter     Heavy-use area     Nutrient pollution     Torrefied     Woodchip    

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Effects of environmental media on the transmission of an inductive link in wireless microsystems

Lei DONG, Li-Feng WANG, Qing-An HUANG

《机械工程前沿（英文）》 2017年 第12卷 第4期   页码 554-556 doi: 10.1007/s11465-017-0450-1

摘要：

An inductive link between two magnetically coupled coils in wireless microsystems is modeled by considering an additional parasitic capacitive link to describe the effect of environmental media. With a system of inductor-capacitor passive wireless sensors, the effects of environmental media are studied theoretically and experimentally for the first time. Results suggest that the capacitive link is non-negligible when the distance between the two coupled coils is comparable with the coupling area, particularly when the environmental medium has a large dielectric constant.

关键词： capacitive link     monitoring correction     passive wireless sensor    

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跨媒体分析与推理：研究进展与发展方向 Review

Yu-xin PENG,Wen-wu ZHU,Yao ZHAO,Chang-sheng XU,Qing-ming HUANG,Han-qing LU,Qing-hua ZHENG,Tie-jun HUANG,Wen GAO

《信息与电子工程前沿（英文）》 2017年 第18卷 第1期   页码 44-57 doi: 10.1631/FITEE.1601787

摘要： 跨媒体分析与推理是计算机科学的热点问题，也是人工智能中一个具有广阔前景的研究方向。目前，尚未有文献对跨媒体分析与推理的现有方法进行归纳总结并给出它的研究进展、挑战及发展方向。为解决这些问题，本文从七个方面进行综述：（1）跨媒体统一表征理论与模型；（2）跨媒体关联理解与深度挖掘；（3）跨媒体知识图谱构建与学习方法；（4）跨媒体知识演化与推理；（5）跨媒体描述与生成；（6）跨媒体智能引擎；（7）跨媒体智能应用。本文的目标是给出跨媒体分析与推理的方法、进展以及发展方向，吸引更多人关注该领域的最新进展，通过探讨面临的挑战和研究方向，为研究者提供重要参考。

关键词： 跨媒体分析；跨媒体推理；跨媒体应用    

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Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO

Jiangkun DU,Jianguo BAO,Wei HU

《环境科学与工程前沿（英文）》 2015年 第9卷 第5期   页码 919-928 doi: 10.1007/s11783-015-0794-x

摘要： In this study, palladium-loaded titania nanotubes was fabricated on a titanium plate (Pd/TiO NTs/Ti) for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of Pd/TiO NTs/Ti electrodes was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The characterization results indicated the generation of Pd nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/TiO NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of −0.7 V ( SCE) and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO NTs/Ti electrode could completely remove chlorine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.

关键词： Pd/TiO2NTs/Ti cathode     chlorophenols     electrocatalytic dechlorination     wastewater treatment    

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标题 作者 时间 类型 操作

Transport of antibiotic resistance plasmids in porous media and the influence of surfactants

Peipei Chen, Chaoqi Chen, Xiqing Li

期刊论文

Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

期刊论文

Social media and mobility landscape: Uncovering spatial patterns of urban human mobility with multi source

Yilan Cui, Xing Xie, Yi Liu

期刊论文

Immunogenicity and protective immunity against otitis media caused by pneumococcus in mice of Hib conjugate

null

期刊论文

analysis and seepage process study on crystal layer in melt crystallization with fractal and porous media

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

期刊论文

Analytical solutions of three-dimensional contaminant transport in uniform flow field in porous media

Hongtao WANG, Huayong WU

期刊论文

Migration and fate of polycyclic aromatic hydrocarbons in bioretention systems with different media:

期刊论文

The influence of social media on stock volatility

Xianjiao WU, Xiaolin WANG, Shudong MA, Qiang YE

期刊论文

Investigation of Generalized SIFs of cracks in 3D piezoelectric media under various crack-face conditions

Jaroon RUNGAMORNRAT, Bounsana CHANSAVANG, Weeraporn PHONGTINNABOOT, Chung Nguyen VAN

期刊论文

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous media

期刊论文

An efficient stochastic dynamic analysis of soil media using radial basis function artificial neural

P. ZAKIAN

期刊论文

Scientifically advanced woody media for improved water quality from livestock woodchip heavy-use areas

Laura Christianson, David DeVallance, Joshua Faulkner, Thomas Basden

期刊论文

Effects of environmental media on the transmission of an inductive link in wireless microsystems

Lei DONG, Li-Feng WANG, Qing-An HUANG

期刊论文

跨媒体分析与推理：研究进展与发展方向

Yu-xin PENG,Wen-wu ZHU,Yao ZHAO,Chang-sheng XU,Qing-ming HUANG,Han-qing LU,Qing-hua ZHENG,Tie-jun HUANG,Wen GAO

期刊论文

Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO

Jiangkun DU,Jianguo BAO,Wei HU

期刊论文