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负载槲皮素的羧甲基壳聚糖水凝胶促进糖尿病大鼠创面愈合

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中国组织工程研究 2025年第4期29卷 692-699页

作者：董美林都海宇刘源连云港市第二人民医院(南京医科大学康达学院附属医院)烧伤整形科江苏省连云港市222000

背景:槲皮素具有抗炎、抗癌、抗氧化、抗衰老、抗抑郁等药理作用,具有极高的药用价值。槲皮素可以促进正常大鼠创面的愈合,但是以槲皮素为主要成分的药物研发较少,限制了其在临床的广泛应用。目的:以水凝胶材料负载槲皮素,探讨槲皮素-... 详细信息

背景:槲皮素具有抗炎、抗癌、抗氧化、抗衰老、抗抑郁等药理作用,具有极高的药用价值。槲皮素可以促进正常大鼠创面的愈合,但是以槲皮素为主要成分的药物研发较少,限制了其在临床的广泛应用。目的:以水凝胶材料负载槲皮素,探讨槲皮素-羧甲基壳聚糖水凝胶在糖尿病大鼠创面中的应用效果。方法:①分别制备羧甲基壳聚糖水凝胶与槲皮素-羧甲基壳聚糖水凝胶,表征水凝胶的微观形貌、体外释药性能。②细胞实验:将小鼠L929成纤维细胞分4组培养,空白对照组常规培养,纯水凝胶组、药物组、载药水凝胶组分别加入羧甲基壳聚糖水凝胶、槲皮素溶液与槲皮素-羧甲基壳聚糖水凝胶,检测细胞增殖与迁移能力。③动物实验:取80只SD大鼠建立糖尿病模型,造模成功后在大鼠背部制作直径2 cm的全层皮肤缺损创面,随机分4组干预,空白对照组、纯水凝胶组、药物组、载药水凝胶组创面分别注射生理盐水、羧甲基壳聚糖水凝胶、槲皮素溶液、槲皮素-羧甲基壳聚糖水凝胶,每组20只,无菌纱布包扎固定。术后观察创面愈合情况、创面病理形态、炎症因子表达及血管生成情况。结果与结论:①扫描电镜下可见两种水凝胶的微观形貌相似,均呈疏松多孔的网络结构,并且槲皮素-羧甲基壳聚糖水凝胶具有良好的体外释药性能。②与空白对照组比较,其他3组细胞增殖与迁移率升高(P<0.05);载药水凝胶组细胞增殖与迁移率高于纯水凝胶组、药物组(P<0.05)。③载药水凝胶组大鼠术后5,11 d的创面愈合率高于其他3组;载药水凝胶组、纯水凝胶组、药物组大鼠术后18 d的创面愈合率基本达到100%,均高于空白对照组(P<0.05)。苏木精-伊红染色显示,载药水凝胶组大鼠术后18 d创面可见完整的皮肤与皮肤附属器,空白对照组、纯水凝胶组、药物组大鼠术后25 d创面可见完整的皮肤与皮肤附属器。载药水凝胶组大鼠创面术后5,11,18 d的创面肿瘤坏死因子α、白细胞介素6水平均低于空白对照组(P<0.05),术后11,18 d的创面转化生长因子β1水平低于空白对照组(P<0.05)。载药水凝胶组大鼠术后11,18 d的CD31、血管内皮生长因子αmRNA表达量均高于其他3组(P<0.05)。④结果表明,槲皮素-羧甲基壳聚糖水凝胶中的槲皮素可发挥调节炎症反应、促进血管新生的作用,可通过促进成纤维细胞的增殖与迁移,促进糖尿病大鼠创面的愈合。

关键词：创面愈合槲皮素敷料水凝胶糖尿病创面羧甲基壳聚糖皮肤创面成纤维细胞

Deposition pattern of stony and muddy debris flow at the confluence area

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Journal of Mountain Science 2021年第3期18卷 622-634页

作者： du Cui School of civil engineering Henan University of Science and TechnologyLuoyang 471023China

Debris flow fan affects the river profile and landscape *** propagation of multiple debris flows along a river can cause inundation and breaching risk,which can be exemplified by the Min River after the Wenchuan earthquake,Sichuan province,*** this work,large flume tests were conducted to examine the interactions between debris flows and water current with the fan geometry,momentum,runout distance,deposited width,the relative water level upstream and dominated *** results reveal that stony flow commonly travels at a high speed and forms a long rectangle shape fan,while the muddy flow generally travels at a low speed and forms a fan-shaped depositional *** stony flow can block a river even when the momentum is close to the water current;the muddy flow can block a river when the momentum is lower than that of water *** case of complete river damming,the relative water level upstream indicates that the inundation risk from the muddy flow damming river would be higher than the inundation risk of stony *** diversion ratio of muddy flow decreases as damming *** of dimensionless numbers reveals that stony flow is dominated by grain collision stress combined with turbulent mixing stress,while the muddy flow is dominated by viscous shear stress over friction *** fan geometry,damming ratio,diversion ratio,and the dominated stress all together indicate that stony flow strongly interacts with water current while the muddy flow does *** results can be helpful for understanding the physical interactions between water current and various debris flows,and debris flow dynamics at the channel confluence area.

关键词： Stony flows Muddy flows Physical interactions Damming ratio Dominated stress

On Some Model Equations of Euler and Navier-Stokes Equations

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Chinese Annals of Mathematics,Series B 2021年第2期42卷 281-290页

作者： Dapeng du Department of Mathematics and statistics Northeast Normal UniversityChangchun 130024China

The author proposes a two-dimensional generalization of Constantin-Lax-Majda model. Some results about singular solutions are given. This model might be the first step toward the singular solutions of the Euler equations. Along the same line(vorticity formulation), the author presents some further model equations. He possibly models various aspects of difficulties related with the singular solutions of the Euler and Navier-Stokes equations. Some discussions on the possible connection between turbulence and the singular solutions of the Navier-Stokes equations are made.

关键词： Euler equations Navier-Stokes equations Singular solutions Turbulence

Higher order Poisson kernels and L^p polyharmonic boundary value problems in Lipschitz domains

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Science China Mathematics 2020年第6期63卷 1065-1106页

作者： Zhihua du Department of Mathematics Jinan UniversityGuangzhou 510632China

In this article, we introduce higher order conjugate Poisson and Poisson kernels, which are higher order analogues of the classical conjugate Poisson and Poisson kernels, as well as the polyharmonic fundamental solutions, and define multi-layer potentials in terms of the Poisson field and the polyharmonic fundamental solutions, in which the former is formed by the higher order conjugate Poisson and the Poisson kernels. Then by the multi-layer potentials, we solve three classes of boundary value problems(i.e., Dirichlet, Neumann and regularity problems) with L^p boundary data for polyharmonic equations in Lipschitz domains and give integral representation(or potential) solutions of these problems.

关键词： polyharmonic equation boundary value problem higher order Poisson and conjugate Poisson kernel integral representation

Anisotropic Rock Poroelasticity Evolution in Ultra-low Permeability Sandstones under Pore Pressure,Confining Pressure,and Temperature:Experiments with Biot's Coefficient

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Acta Geologica Sinica(English Edition) 2021年第3期95卷 937-945页

作者： du Shuheng State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This study aimed to show anisotropic poroelasticity evolution in ultra-low permeability reservoirs under pore pressure,confining pressure,and *** groups of experiments examining Biot's coefficient under different conditions were carried *** showed that Biot's coefficient decreased with increased pore pressure,and the variation trend is linear,but the decreasing rate is variable between ***'s coefficient increased with increased confining pressure;the variation trend is linear,but the increasing rate varies by material as ***,Biot's coefficient remains stable with increased ***,clay mineral content,particle arrangement,and pore arrangement showed impacts on Biot's *** strong hydrophilic clay minerals,expansion in water could result in a strong surface adsorption reaction,which could result in an increased fluid bulk modulus and higher Biot's *** skeleton minerals with strong lipophilicity,such as quartz and feldspar,increased oil saturation will also result in an adsorption reaction,leading to increased fluid bulk modulus and a higher Biot's *** study's conclusions provide evidence of poroelasticity evolution of ultra-low permeability and help the enhancing oil recovery(EOR)process.

关键词： Biot's coefficient ultra-low permeability pore pressure confining pressure temperature

Recent Advances in Electrode Design Based on One-Dimensional Nanostructure Arrays for Proton Exchange Membrane Fuel Cell Applications

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Engineering 2021年第1期7卷 33-49页

作者： Shangfeng du School of Chemical Engineering University of BirminghamBirmingham B152TTUK

One-dimensional(1D)Pt-based electrocatalysts demonstrate outstanding catalytic activities and stability toward the oxygen reduction reaction(ORR).Advances in three-dimensional(3D)ordered electrodes based on 1D Pt-based nanostructure arrays have revealed great potential for developing highperformance proton exchange membrane fuel cells(PEMFCs),in particular for addressing the mass transfer and durability challenges of Pt/C nanoparticle *** paper reviews recent progress in the field,with a focus on the 3D ordered electrodes based on self-standing Pt nanowire *** thin-film(NSTF)catalysts are discussed along with electrodes made from Pt-based nanoparticles deposited on arrays of polymer nanowires,and carbon and TiO2 *** on electrodes from Pt-based nanotube arrays are also *** importance of size,surface properties,and the distribution control of 1D catalyst nanostructures is ***,challenges and future development opportunities are addressed regarding increasing electrochemical surface area(ECSA)and quantifying oxygen mass transport resistance for 1D nanostructure array electrodes.

关键词： Proton exchange membrane fuel cell (PEMFC) Electrode One-dimensional(1D) Oxygen reduction reaction(ORR) Catalyst Ordered

An Alternative Way of Utilizing Fixed Point Theory

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Chinese Annals of Mathematics,Series B 2020年第6期41卷 861-872页

作者： Dapeng du Department of Mathematics and Statistics Northeast Normal UniversityChangchun 130024China

The author proposes an alternative way of using fixed point theory to get the existence for semilinear *** an example,a nonlocal ordinary differential equation is *** idea is to solve homogeneous equations in the *** feature of this method is that it does not need the equation to have special structures,for instance,variational structures,maximum principle,*** speaking,the existence comes from good properties of the suitably linearized *** idea may have wider application.

关键词： Existence Semi-linear equations Fixed point theory Homogeneous linearization

A Practical Regular LDPC Coded Scheme for Physical-Layer Information Security

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China Communications 2024年第5期21卷 190-201页

作者： du Junyi CETC Key Laboratory of Avionic Information System Southwest China Institute of Electronic TechnologyChengdu 610036China

In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from *** this end,we first propose a punctured LDPC coded scheme,where the information bits in a codeword are punctured and only the parity check bits are transmitted to the *** further propose a notion of check node type distribution and derive multi-edge type extrinsic information transfer functions to estimate the security performance,instead of the well-known weak metric bit error *** optimize the check node type distribution in terms of the signal-to-noise ratio(SNR)gap and modify the progressive edge growth algorithm to design finite-length *** results show that our proposed scheme can achieve a lower computational complexity and a smaller security gap,compared to the existing scrambling and puncturing schemes.

关键词： extrinsic information transfer function physical layer scheme secure open channel security gap

Modeling of Fatigue Crack Growth Closure Considering the Integrative Effect of Cyclic Stress Ratio,Specimen Thickness and Poisson's Ratio

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 816-825页

作者： LIU Jiantao du Pingan LIU Xiaobao du Qiang College of Mechanical and Electronic Engineering University of Electronic Science and Technology of China Chengdu 611731 China

Key components of large structures in aeronautics industry are required to be made light and have long enough fatigue *** is of vital importance to estimate the fatigue life of these structures *** the FCG process is affected by various factors,no universal model exists due to the complexity of the *** of the existing models are obtained by fitting the experimental data and could hardly describe the integrative effect of most existing factors *** order to account for the integrative effect of specimen parameters,material property and loading conditions on FCG process,a new model named integrative influence factor model（IIF） is proposed based on the plasticity-induced crack closure *** to the predictions of crack opening ratio（γ） and effective stress intensity factor range ratio（U） with different material under various loading conditions,predictions of γ and U by the IIF model are completely identical to the theoretical results from the plane stress state to the plane strain state when Poisson＇s ratio equals 1/*** Poisson＇s ratio equals 0.3,predictions of γ and U by the IIF model are larger than the predictions by the existing model,and more close to the theoretical *** addition,it describes the influence of R ratios on γ and U effectively in the whole region from-1.0 to ***,several sets of test data of FCG rates in 5 kinds of aluminum alloys with various specimen thicknesses under different loading conditions are used to validate the IIF model,most of the test data are situated on the predicted curves or between the two curves that represent the specimen with different thicknesses under the same stress *** of the test data slightly departure from the predictions by the IIF model due to the surface roughness and errors in ***,based on the analysis of the physical rule of crack opening ratios,a relative thickness of specimen is defined to describe the influence of mate

关键词： fatigue crack growth crack opening stress cyclic stress ratio constraint factor Poisson's ratio stress intensity factor