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Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

International journal of Oral Science 2015年第3期7卷 179-186页

作者： Fei yu Owen Addison Stephen j Baker Alison j Davenport School of Metallurgy and Materials University of Birmingham Biomaterials Unit College of Medical and Dental Sciences University of Birmingham School of Geography Earth and Environmental Sciences University of Birmingham

Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide（LpS）, a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LpS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti（ASTM Grade 2, Grade 4 and Grade 5）. Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to p H of the immersion solution. However, LpS significantly inhibited Ti release under the most acidic conditions（p H 2）, which may develop in localized corrosion sites, but promoted dissolution at p H 4–7, which would be more commonly encountered *** observed pattern of sensitivity to environmental acidity of the effect of LpS on Ti corrosion has not previously been reported. LpS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.

关键词： corrosion electrochemistry inductively coupled plasma mass spectrometry lipopolysaccharide titanium

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GUIDED WAVES IN MULTILAYERED pLATES: AN IMpROVED ORTHOGONAL pOLYNOMIAL AppROACH

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Acta Mechanica Solida Sinica 2014年第5期27卷 542-550页

作者： jiangong yu j.E.Lefebvre L.Elmaimouni School of Mechanical and power Engineering Henan Polytechnic University Department of Civil Engineering University of Siegen Univ Lille Nord de France F-59000 Lille France UVHC IEMN-DOAE F-59313 Valenciennes Cedex 9 France CNRS UMR 8520 F-59650 Villeneuve d’Ascq France ERSITA Faculte Polydisciplinaire d’Ouarzazate Univ. Ibn Zohr 45000 Ouarzazate Morocco LMTI Faculte des Sciences d’Agadir Universite Ibn Zohr BP 28/S Agadir Morocco

Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomial approach to solve wave propagation in multilayered plates with very dissimilar material properties. Through numerical comparisons among the exact solution, the results from the conventional polynomial approach and from the improved poly- nomial approach, the validity of the improved polynomial approach is illustrated. Finally, it is shown that the conventional polynomial approach can not yield correct continuous normal stress profiles. The improved orthogonul polynomial approach has overcome this drawback.

关键词： multilayered plate orthogonal polynomial dispersion curves stress profiles

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巴西龟代谢性骨病CT诊断病例报告

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动物医学进展 2025年第1期46卷 141-144页

作者：孙嘉徐甘靖宇江蓝刘波俞峰中国农业大学北京100193

代谢性骨病(MBD)是一种因钙缺乏或维生素D 3摄入不足引起的骨骼代谢障碍疾病,其临床表现为骨折、脊椎异常、难产、脱垂等症状。计算机断层扫描(CT)在兽医临床中应用的逐渐增加为龟、鳖类MBD提供了新的诊断方式。该病例中红耳巴西龟血检... 详细信息

代谢性骨病(MBD)是一种因钙缺乏或维生素D 3摄入不足引起的骨骼代谢障碍疾病,其临床表现为骨折、脊椎异常、难产、脱垂等症状。计算机断层扫描(CT)在兽医临床中应用的逐渐增加为龟、鳖类MBD提供了新的诊断方式。该病例中红耳巴西龟血检结果提示其肾脏、肝脏功能损害,钙磷代谢异常。CT扫查提示患龟全身组织大面积矿化、背甲凹陷,定量测量患龟背椎骨、神经骨和胸膜骨3处的骨骼密度远低于正常龟,诊断患龟有严重的MBD。治疗方案为对症治疗、改善饲养管理条件,同时对该龟补充维生素D 3。该病例报告系统陈述了龟鳖MBD的诊疗流程,同时表明了CT扫查可为龟鳖MBD精确诊断、治疗和预后提供新的参考。

关键词：龟代谢性骨病计算机断层扫描骨密度

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Role of stem cell therapies in treating chronic wounds:A systematic review

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World journal of Stem Cells 2020年第7期12卷 659-675页

作者： Anjali C Raghuram Roy p yu Andrea Y Lo Cynthia j Sung Melissa Bircan Holly j Thompson Alex K Wong Division of plastic and Reconstructive Surgery Keck School of Medicine of USCLos AngelesCA 90033United States Wilson Dental Library Herman Ostrow School of Dentistry of USCLos AngelesCA 90089United States

BACKGROUND The impairment of cutaneous wound healing results in chronic,non-healing wounds that are caused by altered wound environment oxygenation,tissue injury,and permissive microbial *** modalities for the treatment of these wounds inadequately address the complex changes involved in chronic wound ***,stem cell therapies have emerged as a potential therapeutic modality to promote cutaneous regeneration through trophic and paracrine *** To investigate current literature regarding use of stem cell therapies for the clinical treatment of chronic,non-healing *** pubMed,EMBASE,Cochrane Library,Web of Science,and Scopus were queried with combinations of the search terms“mesenchymal stem cells,”“adult stem cells,”“embryonic stem cells,”“erythroid precursor cells,”“stem cell therapies,”and“chronic wounds”in order to find relevant articles published between the years of 2000 and 2019 to review a 20-year *** lists from the articles were reviewed to identify additional pertinent *** manuscripts(reviews,case reports/series,retrospective/prospective studies,and clinical trials)were evaluated by the authors for their depiction of clinical stem cell therapy *** were extracted from the articles using a standardized collection *** A total of 43 articles describing the use of stem cell therapies for the treatment of chronic wounds were included in this *** stem cell therapies have been explored in in vitro and in vivo applications in the past,recent efforts are geared towards assessing their clinical role.A review of the literature revealed that adipose-derived stem cells,bone marrow-derived stem cells,bone marrowderived mononuclear cells,epidermally-derived mesenchymal stem cells,fibroblast stem cells,keratinocyte stem cells,placental mesenchymal stem cells,and umbilical cord mesenchymal stem cells have all been employed in the treatment of chronic wounds of various etiolo

关键词： Mesenchymal stem cells Adult stem cells Embryonic stem cells Erythroid precursor cells Stem cell therapies Chronic wounds

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Effects of Y211 phase contents on the critical current density j_c and microstructural analysis in YBCO bulk superconductors

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Rare Metals 2002年第4期21卷 282-288页

作者： SHA jianjun, yu Gang, and yu jinnanChina Institute of Atomic Energy, p. O. Box 275-51, Beijing 102413, China China Institute of Atomic Energy P.O. Box 275-51 北京 102413

YBCO bulk superconductors were prepared by the solid state reaction andtop-seed-melt-textured growth (TSMTG) process. By using the AC susceptibility measurement, thecritical transition temperature T_c of samples is 91.5 K for the highest value, and the transitionwidth ΔT_c is less than 1 K. The highest magnetization critical current densities j_c achieved 10~6A/cm^2 under 5 T at 10 K and 1.35X10^4 A/cm^2 under 2 T at 70 K (H//c), respectively. The resultscombining the SEM observation indicate that doping of Y211 particles is more effective in improvingthe growth quality of melt-textured YBCO superconductor and in reducing the micro-cracks ofspecimens. Doping of Y_2O_3 powder forms the rod-shaped Y211 particles, but doping of Y211 particlesdirectly to matrix materials forms the spherical Y211 particles mainly. Combining themicrostructures with j_c measurements shows that the interfaces are most important on flux bundlepinning, in which the gradient of free energy is larger than that of other place between the Y211particles and the Y123 matrix materials.

关键词： quasi-single domain melt-textured Y211 particles critical current density magnetic flux pinning

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消失的“受害者”:难民新闻图像的全球生产机制及其传播网络

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新闻与传播评论 2025年第1期78卷 5-20页

作者：周莉于子晴华中师范大学新闻传播学院湖北武汉430079

作为重大事件的叙事载体,新闻图像在推动国际议题的全球传播中发挥着重要作用。针对全球危机的直接后果——难民议题,对198个国家的474786张难民图像进行视觉框架提取、人物情感识别和传播网络分析后发现:全球难民新闻图像的视觉呈现具... 详细信息

作为重大事件的叙事载体,新闻图像在推动国际议题的全球传播中发挥着重要作用。针对全球危机的直接后果——难民议题,对198个国家的474786张难民图像进行视觉框架提取、人物情感识别和传播网络分析后发现:全球难民新闻图像的视觉呈现具有符号偏离、情感对立与叙事矛盾等特点,这种视觉话语冲突受到经济、政治、宗教文化等语境因素的影响;全球媒体在难民图像共享上呈现较强的联动效应,形成显著的圈层结构和媒体群落。由此,国际议题自身属性为图像生产的场景化提供了条件,国家内部语境因素是其图像生产策略的主要线索,国际权力则是构建全球视觉传播生态的底层逻辑。

关键词：难民新闻图像国际议题全球传播传播网络

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农业社会化服务对长江经济带农业生态效率的影响——基于劳动力和资本要素配置视角

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华东经济管理 2025年第1期39卷 21-30页

作者：陈卫洪于晴贵州大学经济学院贵州贵阳550000

农业社会化服务是实现农业生产绿色转型的重要途径。文章基于2009—2021年长江经济带110个地级市面板数据对农业生态效率进行测算,并采用固定效应模型、中介效应模型和门槛效应模型探究农业社会化服务对农业生态效率的影响及内在机制。... 详细信息

农业社会化服务是实现农业生产绿色转型的重要途径。文章基于2009—2021年长江经济带110个地级市面板数据对农业生态效率进行测算,并采用固定效应模型、中介效应模型和门槛效应模型探究农业社会化服务对农业生态效率的影响及内在机制。研究发现:长江经济带农业生态效率总体上呈“U”型变化趋势,上游农业生态效率高于中游、下游及总体区域;农业社会化服务对农业生态效率具有显著的促进作用,且可以通过优化劳动力和资本要素配置间接提升农业生态效率。门槛检验进一步表明,农业社会化服务对农业生态效率的影响呈现边际效应递增的非线性特征。由此,长江经济带应加快完善农业社会化服务体系,以促进农业生态效率提升。

关键词：农业社会化服务劳动力资本要素配置农业生态效率

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DSC analyses of static and dynamic precipitation of an Al–Mg–Si–Cu aluminum alloy

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progress in Natural Science:Materials International 2015年第2期25卷 153-158页

作者： Manping Liu Zhenjie Wu Rui Yang jiangtao Wei Yingda yu p?l C. Skaret Hans j. Roven School of Materials Science and Engineering Jiangsu Province Key Laboratory of Materials Tribology Jiangsu University Department of Materials Science and Engineering Norwegian University of Science and Technology (NTNU)

In the present investigation, both static and dynamic precipitations of an Al–Mg–Si–Cu aluminum alloy after solid-solution treatment(SST)were comparatively analyzed using differential scanning calorimetry(DSC). Dynamic aging was performed in the SST alloy through equal channel angular pressing(ECAp) at different temperatures of room temperature, 110, 170, 191 and 300 1C. For comparison, static artificial aging was conducted in the SST alloy at 191 1C with two aging times of 4 and 10 h. The DSC analyses reveal that the dynamic precipitation has occurred in the ECAped samples, while the activation energies associated with the strengthening precipitates in the dynamic samples are considerably higher than the energies in the SST and static aged samples. The higher activation energies are probably attributed to the smaller grains and higher dislocation density developed after ECAp. The results in the present investigation allow the prediction of the type of the dynamic precipitates to influence the strength of the ultrafine grained alloy during ECAp at various temperatures.

关键词： Differential scanning calorimetry Al–Mg–Si–Cu aluminum alloy Dynamic aging precipitation behaviors Equal channel angular pressing Severe plastic deformation

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A Nanoindentation Study on the Rheological Behaviour of Bituminous Binders

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武汉理工大学学报 2010年第17期32卷 47-50页

作者： LIU G VAN DE VEN M WU S p yu j Y MOLENAAR A Faculty of Civil Engineering and Geosciences Delft University of TechnologyP.O. Box 50482600 GA Delftthe Netherlands Key Laboratory of Silicate Materials Science and Engineering of Ministry of Education Wuhan University of TechnologyWuhan 430070China

This paper reports the nanoindentation results of three bituminous binders,C-Fix,and standard penetration grade 40/60 bitumen and organo-montmorillonite (OMt) modified bitumen. Under a load applied by the Berkovich diamond indenter,a loading and unloading history was recorded and the load-displacement curve was analyzed as a function of time. The software can directly give an output value of the modulus for C-Fix. However the result was dependent on the loading history. Due to increasing viscoelastic behaviour,the output value of the modulus for base bitumen was always negative,even with a very short unloading time. In conclusion,the modulus calculated by the software was not suitable for the bituminous binders due to their time-dependence. The nanoindentation curve during the loading phase of bitumen could be described by the adopted creep model. The results indicated that the OMt modified bitumen showed a high creep resistance than the base bitumen due to the OMt's reinforcement.

关键词： nanoindentation bitumen viscoelasticity creep

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Effect of stress profile on microstructure evolution of cold-drawn commercially pure aluminum wire analyzed by finite element simulation

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journal of Materials Science & Technology 2018年第7期34卷 1214-1221页

作者： Y.K.Zhu Q.Y.Chen Q.Wang H.Y.yu R.Li j.p.Hou Z.j.Zhang G.p.Zhang Z.F.Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences National Quality Supervision & Inspection Center of Electrical Equipment Safety performance Zhejiang Huadian Equipment Testing Institute

The evolution of microstructure in the drawing process of commercially pure aluminum wire （CpAW） does not only depend on the nature of materials, but also on the stress profile. In this study, the effect of stress profile on the texture evolution of the CpAW was systematically investigated by combining the numerical simulation and the microstructure observation. The results show that the tensile stress at the wire center promotes the formation of 〈111〉 texture, whereas the shear stress nearby the rim makes little contribution to the texture formation. Therefore, the 〈111 〉 texture at the wire center is stronger than that in the surface layer, which also results in a higher microhardness at the center of the CpAW under axial loading.2017 published by Elsevier Ltd on behalf of The editorial office of journal of Materials Science ＆ Technology.

关键词： Commercially pure aluminum wire Cold drawing Texture Finite element simulation Stress profile

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