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Dynamical Analysis of Toxin Producing Model with Delay

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Journal of Mathematical Research with Applications 2021年第1期41卷 33-48页

作者： Xiaona Li College of Mathematics and Statistics Yili Normal University

In this paper, a toxin producing phytoplankton-zooplankton model with inhibitory substrate and time delay is investigated. A discrete time delay is induced to both of the consume response function and distribution of toxic substance term. Moreover, Tissiet type function is used for zooplankton grazing to account for the effect of toxication by the TPP population. The conditions to guarantee the coexistence of two species and stability of coexistence equilibrium are given. In particular, we show that there exist critical values of the delay parameters below which the coexistence equilibrium is stable and above which it is unstable. Hopf bifurcation occurs when the delay parameters cross their critical values. Some numerical simulations are executed to validate the analytical findings.

关键词： phytoplankton zooplankton toxin delay stability

Roadmap of environmental health research on emerging contaminants: Inspiration from the studies on engineered nanomaterials

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Eco-Environment & Health 2022年第3期1卷 181-197页

作者： Xiaona Li Feng He Zhenyu Wang Baoshan Xing Institute of Environmental Processes and Pollution Control and School of Environment and Civil EngineeringJiangnan UniversityWuxi 214122China Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology Jiangnan UniversityWuxi 214122China Stockbridge School of Agriculture University of MassachusettsAmherstMA 01003United States

Research on the environmental health of emerging contaminants is critical to understand their risks before causing severe harm.However,the low environmental concentrations,complex behaviors,and toxicology of emerging contaminants present enormous challenges for researchers.Here,we reviewed the research on the environmental health of engineered nanomaterials(ENMs),one of the typical emerging contaminants,to enlighten pathways for future research on emerging contaminants at their initial exploratory stage.To date,some developed pretreatment methods and detection technologies have been established for the determination of ENMs in natural environments.The mechanisms underlying the transfer and transformation of ENMs have been systematically explored in laboratory studies.The mechanisms of ENMs-induced toxicity have also been preliminarily clarified at genetic,cellular,individual,and short food chain levels,providing not only a theoretical basis for revealing the risk change and environmental health effects of ENMs in natural environments but also a methodological guidance for studying environmental health of other emerging contaminants.Nonetheless,due to the interaction of multiple environmental factors and the high diversity of organisms in natural environments,health effects observed in laboratory studies likely differ from those in natural environments.We propose a holistic approach and mesocosmic model ecosystems to systematically carry out environmental health research on emerging contaminants,obtaining data that determine the objectivity and accuracy of risk assessment.

关键词： Emerging contaminants Engineered nanomaterials Holistic approach Mesocosmic systems Natural environments

Growth Ring-dependent Fracture Toughness of Sea Urchin Spines Estimated by Boundary Effect Model

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Journal of Bionic Engineering 2022年第5期19卷 1472-1480页

作者： Xiaona Liu Simin liang Yingying li Hongmei Ji Xiaowu li Department of Materials Physics and Chemistry School of Material Science and EngineeringNortheastern UniversityShenyang 110819China Key Laboratory for Anistropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China State key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Although the fracture behavior of sea urchin spines has been extensively investigated,there is as yet a lack of quantitative estimation on the effect of growth rings on the fracture properties of sea urchin spines.In sea urchin spines,much denser pores present in growth rings rather than porous layers.The tensile strength and fracture toughness of sea urchin spine samples with different numbers of growth rings are measured by the Boundary Effect Model(BEM).The experimental results of single-edge notched three-point bending tests indicate that the BEM is an appropriate method to estimate the fracture toughness of the present porous sea urchin spines,and the number of growth rings plays an important role in the fracture properties of spines.Specifically,the tensile strength and fracture toughness of sea urchin spines can be significantly improved with the increase in the number of growth rings,and their fracture toughness can even reach a relatively high value compared with some other porous materials with an identical porosity.The present research findings are expected to provide a fundamental insight into the design of high-performance bionic materials with a highly porous structure.

关键词： Sea urchin spine Growth ring Boundary Effect Model Porous structure Tensile strength Fracture toughness

Nucleophilic amino acids as a renewable alternative to petrochemically-derived amines in glycerol epoxy resins

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Journal of Bioresources and Bioproducts 2024年第2期9卷 222-232页

作者： Yunyi liang Yonghong Luo Yingji Wu Xiaona Li Quyet Van Le Jianzhang li Changlei Xia Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China Department of Materials Science and Engineering Institute of Green Manufacturing TechnologyKorea UniversitySeoul 02841South Korea

The standard epoxy resin curing agents revealed are from unsustainable petroleum-based sources,which produce poisonous exhaust when cured.Amino acids,a bio-based epoxy curing agent with amino and carboxyl groups,are another potential curing agent.Water-soluble epoxy resins cured with lysine(Lys),glutamic acid(Glu),leucine(Leu),and serine(Ser)as amino acids were inves-tigated.The results showed that the water-soluble epoxy resin(glycerol epoxy resins,GER)was cured with Lys and Glu after reacting.Fourier transform infrared(FT-IR)spectroscopic analysis of the GER-Lys showed that the amino and carboxyl groups of Lys primarily reacted with the epoxy groups of GER.The elongation at break of Lys-cured GER(GER-Lys)cured at 70℃ with a molar ratio of 1꞉0.75 was 75.32%.The fact that elongations at break of GER-Lys(79.43%)were higher than those of GER-Glu(17.33%),respectively supports the decrease of crosslinking density by the amino acid-cured GER reaction.The potential of Lys and Glu alternatives for petrochemical amines is demonstrated and provides promising opportunities for industrial application.

关键词： Curing agent Amino acids Bio-based epoxy resins Lysine Glutamic acid

Effective adsorption of sulfamethoxazole, bisphenol A and methyl orange on nanoporous carbon derived from metal-organic frameworks

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Journal of Environmental Sciences 2018年第1期30卷 250-259页

作者： Xiaona Li Hui Yuan Xie Quan Shuo Chen Shijie You Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) School of Environmental Science and TechnologyDalian University of Technology State Key Laboratory of Urban Water Resource and Environment School of Environment Harbin Institute of Technology

Nanoporous carbons（NPCs） derived from metal–organic frameworks（MOFs） are attracting increasing attention in many areas by virtue of their high specific surface area, large pore volume and unique porosity. The present work reports the preparation of an NPC with high surface area（1731 m^2/g） and pore volume（1.68 cm^3/g） by direct carbonization of MOF-5. We examined the adsorption of three typical contaminants from aqueous solutions, i.e., sulfamethoxazole（SMX）,bisphenol A（BPA） and methyl orange（MO）, by using the as-prepared NPC. The results demonstrated that NPC could adsorb the contaminants effectively, with adsorption capacity（qm） of 625 mg/g（SMX）, 757 mg/g（BPA） and 872 mg/g（MO）, respectively. These values were approximately 1.0-3.2 times higher than those obtained for single-walled carbon nanotubes（SWCNTs） and commercial powder active carbon（PAC） under the same conditions. With its high surface area and unique meso/macropore structure, the enhanced adsorption of NPC most likely originates from the cooperative interaction of a pore-filling mechanism, electrostatic interaction,and hydrogen bonding. In particular, the p H value has a crucial impact on adsorption, suggesting the significant contribution of electrostatic interaction between NPC and the contaminants. This study provides a proof-of-concept demonstration of MOF-derived nanoporous carbons as effective adsorbents of contaminants for water treatment.

关键词： Nanoporous carbon MOFs Adsorption Sulfamethoxazole Bisphenol A Methyl orange

The enhancing effect and promoting mechanisms of the stereoisomeric monoterpene alcohol esters as enhancers for drugs with different physicochemical properties

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Asian Journal of Pharmaceutical Sciences 2022年第1期17卷 139-152页

作者： Heping Wang Yan li Chunyan Wang Jing Wang Bo Ren Xiaona Li Mingzhu li Dandan Geng Chensi Wu ligang Zhao School of Pharmacy North China University of Science and TechnologyTangshan 063000China Dept of Pharmacy Tangshan Maternal and Child Health HospitalTangshan 063000China Tangshan key laboratory of novel preparations and drug release technology Tangshan 063000China

To explore the structure-activity connections of amphiphilic permeation enhancers containing the length of the hydrophobic chains as well as the properties of the polar head,O-acylgeraniol and O-acylnerol derivatives were synthesized from geraniol/nerol(cis-isomer of geraniol) and pharmaceutical excipient acids in this research. Their promotion of the percutaneous absorption of three drugs as the model, flurbiprofen(FP), isosorbide dinitrate(ISDN) and donepezil(DNP), which were selected based on their physicochemical properties,was tested by in vitro skin penetration and in vivo. Molecular simulation, ATR-FTIR, CLSM and histological observation were implement to evaluate the mode of action of the enhancers.The results indicated that(E)-3,7-dimethyl-2,6-octadien-1-yl tetradecanoate(GER-C14, trans-)achieved the highest enhancement ability for the three drugs;additionally, the in vivo results obtained were in good correlation with the in vitro data. Molecular docking results suggested that enhancers loosen the hydrogen bonds between ceramides, and the results of molecular simulation indicated that GER-C14, NER-C14 could insert into the middle of the lipid bilayer to form an independent phase. According to ATR-FTIR and histological evaluation, the enhancers extracted lipids and influenced the protein region, thereby disturbing the skin array. In addition, CLSM described the dynamic effects of enhancers on lipids between stratum corneum(SC) cells. In conclusion, GER-C14 had a better penetration promotion effect, which broadened our understanding of stereoisomeric penetration enhancers.

关键词： O-acylgeraniol derivatives O-acylnerol derivatives Transdermal drug delivery system In vitro and in vivo correlation Enhancing mechanism

Boundedness for a Class of Operators on Weighted Morrey Space with RD-measure

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Journal of Partial Differential Equations 2022年第4期35卷 395-408页

作者： CUI xiaona LU Yongjin li Mengmeng Department of Mathematics and Information Science Henan Normal UniversityXinxiang 453007China Department of Mathematics and Statistics Oakland UniversityRochesterMI48309USA College of International Education Henan Normal UniversityXinxiang 453007China.

this paper,we study a class of sublinear operators and their commutators with a weighted BMO function.We first give the definition of a weighted Morrey space Lpo(X)where X is an RD-measure and w is the weight function.The weighted Morrey spaces arise from studying the local behavior of solutions to certain partial differential equations.We will show that the aforementioned class of operators and their communtators with a weighted BMO function are bounded in the weighted Morrey space LPpto(X)provided that the weight function w belongs to the Ap(μ)-class and satisfiesthereverseHolder'scondition.

关键词： Weighted Morrey space RD-measure commutator

Spectrum-Efficient User Association in Caching Enabled Dense Small Cell Network

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China Communications 2023年第3期20卷 86-104页

作者： Junyu liu Min Sheng xiaona Zhao Shuang Ni Jiandong li State Key Laboratory of ISN Xidian UniversityXi’an 710071China Department of Broadband Communication Peng Cheng LaboratoryShenzhen 518055China

In this paper,we reveal the fundamental limitation of network densification on the performance of caching enabled small cell network(CSCN)under two typical user association rules,namely,contentand distance-based rules.It indicates that immoderately caching content would significantly change the interference distribution in CSCN,which may degrade the network area spectral efficiency(ASE).Meanwhile,it is shown that content-based rule outperforms the distance-based rule in terms of network ASE only when small cell base stations(BSs)are sparsely deployed with low decoding thresholds.Moreover,it is proved that network ASE under distance-based user association serves as the upper bound of that under content-based rule in dense BS regime.To enable more spectrum-efficient user association in dense CSCN,we further optimize network ASE by designing a probabilistic content retrieving strategy based on distance-based rule.With the optimized retrieving probability,network ASE could be substantially enhanced and even increase with the growing BS density in dense BS regime.

关键词： caching dense network user association

Sorption and desorption characteristics of sulfamethazine in three different soils before and after removal of organic matter

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Pedosphere 2021年第5期31卷 796-806页

作者： Xiaona Li Yang SONG Mingyun JIA Fang WANG Yongrong BIAN Xin JIANG CAS Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049(China) Institute of Botany Jiangsu Province and Chinese Academy of SciencesNanjing 210014(China)

Organic matter(OM)is the most critical factor in controlling the sorption-desorption of SMZ in soil,however,few studies have explored the effects of OM removal on these important behaviors among different soils.Batch experiments were conducted to investigate the sorption and desorption characteristics of SMZ in three different soils:fluvo-aquic soil(FS),paddy soil(PS),and red soil(RS).The SMZ sorption in the evaluated soils was dominated by physisorption.The SMZ sorption capacities of FS and PS,which had a relatively higher OM content than RS,were higher than that of RS.The SMZ sorption in FS was dominated by linear partitioning.In contrast,the SMZ sorption in PS and RS was mainly nonlinear surface adsorption.After OM removal,the SMZ sorption capacity was significantly reduced in FS but increased in PS and RS.Furthermore,OM removal restrained the sorption intensity of SMZ in soils.Relatively higher OM and clay contents inhibited the SMZ desorption in FS and PS.The strong negative desorption hysteresis of SMZ in the three soils indicated that SMZ was able to move into the soil solution,thereby posing a risk to humans.Taken together,the findings of this study showed that OM indeed plays an important role during SMZ sorption-desorption in soil.

关键词： antibiotics isotherm kinetics sorption-desorption soil organic matter