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Toxic effects of long-term dual or single exposure to oxytetracycline and arsenic on Xenopus tropicalis living in duck wastewater

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Journal of Environmental Sciences 2023年第5期127卷 431-440页

作者： Jianbin Zhao Xinyan li Yanbin Xu Yuxin li Li Zheng Tiangang Luan Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds Institute of Environmental and Ecological EngineeringGuangdong University of TechnologyGuangzhou 510006China School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China Analysis and Test Center Guangdong University of TechnologyGuangzhou 510006China

Direct discharge of aquaculture wastewater may have toxic effects,due to the presence of heavy metals,antibiotics,and even resistant pathogens,but little attention has been given.Here,tanks simulating a wild ecosystem were built to study the effects of long-term exposure to duckwastewater containing oxytetracycline(OTC)and/or arsenic(As)on the growth,physiological function,and gut microbiota evolution of Xenopus tropicalis.The results showed that duck wastewater had no apparent impact on X.tropicalis,but the impact increased significantly(Plis in all treated groups after 72 days of exposure,which indirectly inhibited X.tropicalis growth.Moreover,16S rDNA amplicon sequencing results showed that the gut microbiota structure and metabolic function were perturbed after chronic exposure,which might be the leading cause of growth inhibition.Interestingly,the abundance of intestinal resistance genes(RGs)increased with exposure time owing to the combined direct and indirect effects of stress factors in duck wastewater.Moreover,once the RGs were expressed,the resistance persisted for at least 24 days,especially that conferred by tetA.These results provide evidence of the toxic effects of DW containing OTC(0.1–4.0 mg/L)and/or As(0.3–3.5μg/L)on amphibians and indicate that it is vital to limit the usage of heavy metals and antibiotics on farms to control the biotoxicity of wastewater.

关键词： Duck wastewater Xenopus tropicalis Inhibition Hepatotoxicity Gut microbiota

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A polyphenol-modified chitosan hybrid hydrogel with enhanced antimicrobial and antioxidant activities for rapid healing of diabetic wounds

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Nano Research 2023年第1期16卷 905-916页

作者： Zejun Xu Guiting liu Li Zheng Jun Wu The State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation Sun Yat-Sen Memorial HospitalSun Yat-sen UniversityGuangzhou 510120China Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration Life Science InstitutesGuangxi Medical UniversityNanning 530021China Collaborative Innovation Centre of Regenerative Medicine and Medical BioResource Development and Application Co-constructed by the Province and Ministry Guangxi Medical UniversityNanning 530021China Bioscience and Biomedical Engineering Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Division of life Science The Hong Kong University of Science and TechnologyHong Kong 999077China

High oxidative stress injury and bacterial infection are the main challenges that impair wound healing in diabetic patients.Therefore,a hydrogel with enhanced antimicrobial and antioxidant properties was developed for rapid healing of diabetic wounds.In this study,chitosan methacrylate-gallic acid(CSMA-GA)polymer with antioxidant activity,antimicrobial activity,and ultraviolet(UV)-triggered gelling properties was developed as a hydrogel precursor.Meanwhile,amphiphilic Pluronic F127 molecules were used to load hydrophobic chlorhexidine drug molecules to obtain F127/chlorhexidine nanoparticle(NP)with strong antibacterial activity.Subsequently,F127/chlorhexidine NPs were encapsulated in CSMA-GA hydrogel to further enhance its antibacterial activity.The hybrid hydrogel platform(CSMA-GA/F127/chlorhexidine(CMGFC))exhibited high antibacterial efficiency(>99.9%)and strong reactive oxygen species(ROS)scavenging ability(>80.0%),which effectively protected cells from external oxidative stress(upregulated superoxide dismutase(SOD)and glutathione/oxidized glutathione disulfide(GSH/GSSG)levels and downregulated malondialdehyde(MDA)levels).Moreover,in vivo results proved that the CMGFC hydrogel significantly reduced inflammatory responses(downregulated interleukin-6(IL-6)and upregulated interleukin-10(IL-10)levels),promoted angiogenesis(upregulated vascular endothelial growth factor(VEGF)and platelet endothelial cell adhesion molecule-1(CD 31)levels),and wound healing(enhanced collagen deposition and tissue remodelling).Overall,the CMGFC hydrogel with enhanced antimicrobial and antioxidant properties demonstrated significant potential to enhance diabetic wound healing.

关键词： antimicrobial antioxidant diabetic wound hydrogel

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life-cycle failure probability analysis of deteriorated RC bridges under multiple hazards of earthquakes and strong winds

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 811-823页

作者： zheng Xiaowei li Hongnan Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou 221116China State Lab.of Coastal and Offshore Engineering Faculty of Infrastructure EngineeringDalian University of TechnologyDalian 116024China

Engineering structures may be exposed to one or more extreme hazards during their life-cycles.Current structural design specifications usually treat multiple hazards separately in designing structures and there is a limited probabilistic basis on extreme load combinations.Additionally,the performance of engineering structures will be deteriorated by the aggressive environments during their service periods,such as chloride attack,concrete carbonation,and wind-induced fatigue.This study presents a probabilistic methodology to assess the time-dependent failure probability of RC bridges with chloride-induced corrosion under the multiple hazards of earthquakes and strong winds.The loss of cross-section area of reinforcements and the reduction in strength of reinforcing steel and concrete cover induced by the chloride attack are considered.Moreover,the Poisson model is employed to obtain the occurrence probabilities of the individual and concurrent earthquake and strong wind events.The convolution integral is used to determine the joint probability distribution of combined load effects under simultaneous earthquakes and strong winds.Numerical results indicate that the structural failure probability under multiple hazards increases significantly during the bridge′s life-cycle due to the chloride corrosion effect.The contribution of each hazard event on the total structural failure probability varies with time.Thus,neglecting the combined influences of multiple hazards and chloride-induced corrosion may bring erroneous predictions in failure probability estimates of RC bridges.

关键词： life-cycle multihazard chloride occurrence model failure probability

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Design and control of deformable quadrotor with varying length arms

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Science China(Technological Sciences) 2023年第5期66卷 1225-1234页

作者： SUN YiChong XIE MingNa li YeHui NG WingYin ZHANG Heng Li Zheng Multi-Scale Medical Robotics Centre The Chinese University of Hong KongHong Kong 999077China Department of Surgery The Chinese University of Hong KongHong Kong 999077China Department of Electrical and Electronic Engineering The University of Hong KongHong Kong 999077China College of Optoelectronic Engineering Chongqing UniversityChongqing 400044China

Deformable quadrotors can manipulate their specific structure for specialized tasks or excellent flight performance under diverse conditions.With added deformation mechanism,the quadrotor exhibits higher flexibility;however,this is accompanied by difficulties in modeling analysis and controller design,which are crucial issues.Here,a novel deformable quadrotor that can alter its arm's length is designed by combining the crank-slider mechanism and cross-configuration.The dynamics,including the attitude and position systems,are analyzed and the former is further described as switched linear parameter varying(SLPV)systems from a control-oriented perspective.In addition,a combined SLPV/proportion-integration-differentiation(PID)attitude controller is developed to handle different deformable quadrotor modes,which guarantees the stability of the closed-loop attitude system during the deformation process and achieves attitude tracking.Furthermore,together with the cascade PID position controller,the entire flight controller is constructed whose feasibility is verified via fixed-point hovering and trajectory tracking experiments.

关键词： deformable quadrotor mechanics and control LPV systems switched control strategy specialized aerial system

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循环荷载作用下钢筋混凝土短柱受剪性能尺寸效应机理分析

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振动与冲击 2021年第13期40卷 299-305页

作者：付李郑家乐王登峰江南大学环境与土木工程学院江苏无锡214000

为了研究钢筋混凝土短柱在循环荷载作用下受剪性能尺寸效应产生的机理,应用三维刚体弹簧元法,基于梁-拱模型,对3个不同截面尺寸的钢筋混凝土短柱抗剪作用进行分解,结果表明:应用三维刚体弹簧元法能较好地模拟不同截面尺寸钢筋混凝土短... 详细信息

为了研究钢筋混凝土短柱在循环荷载作用下受剪性能尺寸效应产生的机理,应用三维刚体弹簧元法,基于梁-拱模型,对3个不同截面尺寸的钢筋混凝土短柱抗剪作用进行分解,结果表明:应用三维刚体弹簧元法能较好地模拟不同截面尺寸钢筋混凝土短柱在循环荷载下的受剪性能;当达到极限荷载时,随着截面尺寸的增加,以名义剪应力为评判标准的抗剪强度逐渐减小,相比于单调荷载,一次循环后的尺寸效应变化较小,而两次循环(短柱临近破坏)后尺寸效应更加明显,这主要是由于拱模型的抗剪作用急剧下降导致的。

关键词：钢筋混凝土短柱循环荷载尺寸效应梁-拱模型机理分析

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Reconfigurable metamaterial for asymmetric and symmetric elastic wave absorption based on exceptional point in resonant bandgap

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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 1-20页

作者： Jianlin YI zheng WU Rongyu XIA zheng li State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

Elastic wave absorption at subwavelength scale is of significance in many engineering applications.Non-Hermitian metamaterials show the ability in high-efficiency wave absorption.However,the single functionality of metamaterials is an important limitation on their practical applications for lack of tunability and reconfigurability.Here,we propose a tunable and reconfigurable non-Hermitian piezoelectric metamaterial bar,in which piezoelectric bars connect with resonant circuits,to achieve asymmetric unidirectional perfect absorption(UPA)and symmetric bidirectional perfect absorption(PA)at low frequencies.The two functions can be arbitrarily switched by rearranging shunted circuits.Based on the reverberation-ray matrix(RRM)method,an approach is provided to achieve UPA by setting an exceptional point(EP)in the coupled resonant bandgap.By using the transfer matrix method(TMM)and the finite element method(FEM),it is observed that a non-Hermitian pseudo-band forms between two resonant bandgaps,and the EP appears at the bottom of the pseudo-band.In addition,the genetic algorithm is used to accurately and efficiently design the shunted circuits for desired low-frequency UPA and PA.The present work may provide new strategies for vibration suppression and guided waves manipulation in wide potential applications.

关键词： non-Hermitian metamaterial exceptional point(EP) unidirectional perfect absorption(UPA) piezoelectric metamaterial reverberation-ray matrix(RRM)method genetic algorithm

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Dynamic defenses in cyber security:Techniques,methods and challenges Author links open overlay panel

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Digital Communications and Networks 2022年第4期8卷 422-435页

作者： Yu zheng zheng li Xiaolong Xu Qingzhan Zhao School of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044JiangsuChina Key Laboratory for Novel Software Technology Nanjing UniversityNanjing210023JiangsuChina College of Information Science and Technology Shihezi University Geospatial Information Engineering Research CenterChina

Driven by the rapid development of the Internet of Things,cloud computing and other emerging technologies,the connotation of cyberspace is constantly expanding and becoming the fifth dimension of human activities.However,security problems in cyberspace are becoming serious,and traditional defense measures(e.g.,firewall,intrusion detection systems,and security audits)often fall into a passive situation of being prone to attacks and difficult to take effect when responding to new types of network attacks with a higher and higher degree of coordination and intelligence.By constructing and implementing the diverse strategy of dynamic transformation,the configuration characteristics of systems are constantly changing,and the probability of vulnerability exposure is increasing.Therefore,the difficulty and cost of attack are increasing,which provides new ideas for reversing the asymmetric situation of defense and attack in cyberspace.Nonetheless,few related works systematically introduce dynamic defense mechanisms for cyber security.The related concepts and development strategies of dynamic defense are rarely analyzed and summarized.To bridge this gap,we conduct a comprehensive and concrete survey of recent research efforts on dynamic defense in cyber security.Specifically,we firstly introduce basic concepts and define dynamic defense in cyber security.Next,we review the architectures,enabling techniques and methods for moving target defense and mimic defense.This is followed by taxonomically summarizing the implementation and evaluation of dynamic defense.Finally,we discuss some open challenges and opportunities for dynamic defense in cyber security.

关键词： Cyber security Dynamic defense Moving target defense Mimic defense

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CEOs’political ideologies and innovation:Evidence from US public firms

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Economic and Political Studies 2022年第3期10卷 353-367页

作者： Qiang Wu Li Zheng Tanweer Hasan School of Accounting and Finance The Hong Kong Polytechnic UniversityHong Kong SARChina General Electric Global Research Centre NiskayunaNYUSA Independent University BangladeshDhakaBangladesh

Using both the number of patents and the number of citations that the patents receive as the measures of innovation and using political donations as an indicator of the chief executive officer(CEO)’s political preferences,we find that(1)firms led by CEOs with and without political partisanship show no differences in terms of innovation outputs;and(2)there are no differences between firms led by Republican and Democratic CEOs when it comes to innov-ation.The results are robust to a propensity-score-matching regres-sion,a firm fixed effect regression,and alternate measures of innovation.Overall,the results suggest that CEOs’personal political ideologies do not significantly affect their innovation decisions.

关键词： Political ideologies innovation CEO Democrats Republicans

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Compression loading of osteoclasts attenuated micro RNA-146a-5p expression,which promotes angiogenesis by targeting adiponectin

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Science China(life Sciences) 2022年第1期65卷 151-166页

作者： Yue Wang Yunfei zheng Weiran li Department of Orthodontics Peking University School and Hospital of StomatologyBeijing 100081China

Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement.Compression stress also stimulates angiogenesis,which is essential for osteoclastogenesis.However,the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood.In vivo,we found the markers of angiogenesis increased during orthodontic bone remodeling.In vitro,osteoclast-derived exosomes increased proliferation,migration,and tube formation of human umbilical vein endothelial cells(HUVECs),as well as expression of vascular endothelial growth factor and CD31.The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression.Next,we analyzed changes in the micro RNA transcriptome after compression stress and focused on micro RNA146 a-5 p(mi R-146 a),which was significantly decreased by compression.Transfection of an inhibitor of mi R-146 a stimulated angiogenesis of HUVECs while mi R-146 a mimics repressed angiogenesis.Adiponectin(ADP)was confirmed to be a target of mi R-146 a by dual luciferase reporter assay.In HUVECs treated with exosomes,we detected increased ADP which promoted angiogenesis.Knockdown of ADP in HUVECs reduced the promotive effects of exosomes.Our results demonstrate that the decreased mi R-146 a observed in osteoclasts after compression promotes angiogenesis by targeting ADP,suggesting a novel method to interfere with bone remodeling induced by compression stress.

关键词： micro RNA-146a-5p adiponectin angiogenesis compression stress osteoclastogenesis exosomes

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Sulfolane-Graphite Incompatibility and Its Mitigation in li-ion Batteries

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Energy & Environmental Materials 2022年第3期5卷 906-911页

作者： Qinfeng zheng Guanjie li Xiongwen zheng lidan Xing Kang Xu Weishan li Engineering Research Center of MTEES(Ministry of Education) Research Center of BMET(Guangdong Province)Engineering Lab.of OFMHEB(Guangdong Province)Key Lab.of ETESPG(GHEI)and Innovative Platform for ITBMD(Guangzhou Municipality)School of Chemistry and EnvironmentSouth China Normal UniversityGuangzhou 510006China Battery Science Branch Sensor and Electron Devices DirectorateU.S.Army Research LaboratoryAdelphiMD 20783USA

The non-flammability and high oxidation stability of sulfolane(SL)make it an excellent electrolyte candidate for lithium-ion batteries(liBs).However,its incompatibility with graphitic anode prevents the realization of these advantages.To understand how this incompatibility arises on molecular level so that it can be suppressed,we combined theoretical calculation and experimental characterization and reveal that the primary li^(+) solvation sheath in SL is depleted of fluorine source.Upon reduction,SL in such fluorine-poor solvation sheath generates insoluble dimer with poor electronic insulation,hence leading to slow but sustained parasitic reactions.When fluorine content in li^(+)-SL solvation sheath is increased via salt concentration,a high stability liF-rich interphase on graphite can be formed.This new understanding of the failure mechanism of graphite in SL-based electrolyte is of great significance in unlocking many possible electrolyte solvent candidates for the high-voltage cathode materials for next-generation liBs.

关键词： graphite anode interphasial incompatibility mechanism lithium-ion batteries sulfolane

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