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Effects of solidification cooling rate on the corrosion resistance of Mg–Zn–Ca alloy

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Progress in Natural Science:Materials International 2014年第3期24卷 452-457页

作者： debao liu yichi liu Yan Huang Rong Song minfang chen School of Materials Science and Engineering Tianjin University of Technology BCAST Brunel University

This study was carried out to investigate the effect of solidification cooling rate on the corrosion resistance of an Mg–Zn–Ca alloy developed for biomedical applications. A wedge shaped copper mould was used to obtain different solidification cooling rates. Electrochemical and immersion tests were employed to measure the corrosion resistance of Mg–Zn–Ca alloy. It was found that increasing cooling rate resulted in a significant improvement in the corrosion resistance of the Mg–Zn–Ca alloy. The findings were explained in terms of solidification behaviour in association with the change in solubility of the alloying elements, microstructural homogeneity and refinement and chemical homogeneity as well as the increased cooling rates.

关键词： Mg–Zn–Ca alloy Solidification cooling rate Microstructure Corrosion resistance

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海洋大气环境下镁合金腐蚀行为研究进展

稀有金属材料与工程 2024年第4期53卷 1170-1180页

作者：周慧敏黄须强孔令菲陈建鑫高飞刘绍红陈民芳张晋铁镝东北大学材料科学与工程学院辽宁沈阳110819 天津理工大学材料科学与工程学院天津300384 大连交通大学连续挤压教育部工程研究中心辽宁大连116028

本文综合研究了海洋大气环境下镁合金腐蚀行为的研究进展,比较分析了各种因素对腐蚀行为的影响,对当前研究进展进行总结并对未来研究方向进行展望。在海洋大气环境下,表面薄电解质溶液膜的包覆是镁合金发生电化学腐蚀的主要原因,且多发... 详细信息

本文综合研究了海洋大气环境下镁合金腐蚀行为的研究进展,比较分析了各种因素对腐蚀行为的影响,对当前研究进展进行总结并对未来研究方向进行展望。在海洋大气环境下,表面薄电解质溶液膜的包覆是镁合金发生电化学腐蚀的主要原因,且多发生局部腐蚀。相比于内陆大气环境,海洋大气中含有较多无机盐气溶胶颗粒,导致点蚀成为主要的局部腐蚀形式。相对湿度的升高会导致薄电解质膜厚度增加,进而加速整体腐蚀速率。随气温上升,镁合金的大气腐蚀速率线性增加,而空气中的CO_(2)可以抑制NaCl对镁合金的侵蚀。该领域未来需更多关注具体使役环境下合金的腐蚀机理,以及各种环境因素对腐蚀行为的协同作用机制,以指导海洋用镁合金材料的设计和制备。

关键词：镁合金海洋环境腐蚀大气腐蚀局部腐蚀

原儿茶酸对肠毒素大肠杆菌K88诱导的猪小肠上皮细胞程序性坏死和Toll样受体4信号通路的影响

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动物营养学报 2024年第7期36卷 4665-4676页

作者：龚晗秋徐晓叶张敏芳贺鹏伟陈少魁刘玉兰肖勘武汉轻工大学动物科学与营养工程学院动物营养与饲料科学湖北省重点实验室武汉430023

本试验旨在研究原儿茶酸(PCA)对肠毒素大肠杆菌K88(ETEC K88)诱导的猪小肠上皮细胞(IPEC-1细胞)程序性坏死和Toll样受体4(TLR4)信号通路的影响。试验采用2×2因子设计,分为4个组:对照组、PCA组(40μmol/L PCA作用24 h)、ETEC K88组(50... 详细信息

本试验旨在研究原儿茶酸(PCA)对肠毒素大肠杆菌K88(ETEC K88)诱导的猪小肠上皮细胞(IPEC-1细胞)程序性坏死和Toll样受体4(TLR4)信号通路的影响。试验采用2×2因子设计,分为4个组:对照组、PCA组(40μmol/L PCA作用24 h)、ETEC K88组(50倍细胞数ETEC K88作用2 h)和PCA+ETEC K88(40μmol/L PCA作用24 h+50倍细胞数ETEC K88作用2 h)组,每组3个重复。结果显示:1)与对照组相比,ETEC K88组细胞活力显著降低(P<0.05),细胞上清液乳酸脱氢酶(LDH)活性显著升高(P<0.05);与ETEC K88组相比,PCA+ETEC K88组细胞活力显著升高(P<0.05),细胞上清液LDH活性显著降低(P<0.05)。2)与对照组相比,ETEC K88刺激导致细胞形态损伤,超微结构破坏,表现为细胞膜破裂,细胞核皱缩,染色质外溢,线粒体出现肿胀并且空泡化;ETEC K88组细胞坏死率显著升高(P<0.05)。与ETEC K88组相比,添加PCA能够保护细胞形态,PCA+ETEC K88组细胞坏死率显著降低(P<0.05)。3)与对照组相比,ETEC K88组肿瘤坏死因子-α(TNF-α)、TLR4、脂多糖结合蛋白(LBP)、髓样分化蛋白2(MD2)、白细胞介素受体相关激酶1(IRAK1)、肿瘤坏死因子受体相关因子6(TRAF6)和髓样分化因子88(MyD 88)的mRNA相对表达显著升高(P<0.05);与ETEC K88组相比,PCA+ETEC K88组TNF-α、TLR4、LBP、MD2、IRAK1、TRAF6和MyD88的mRNA相对表达量显著降低(P<0.05)。4)与对照组相比,ETEC K88组肿瘤坏死因子受体1(TNFR1)、Fas相关死亡结构域(FADD)、混合系列蛋白激酶样结构域(MLKL)、高迁移率蛋白1(HMGB1)、动力相关蛋白1(Drp1)和磷酸甘油酸变位酶5(PGAM5)的mRNA相对表达量显著升高(P<0.05);与ETEC K88组相比,PCA+ETEC K88组TNFR1、FADD、HMGB1、Drp1和PGAM5的mRNA相对表达量显著降低(P<0.05)。由此可见,PCA可能通过抑制细胞程序性坏死和TLR4信号通路的激活,缓解ETEC K88诱导的IPEC-1细胞的炎症反应和损伤。

关键词：肠毒素大肠杆菌K88 原儿茶酸 IPEC-1 程序性坏死 Toll样受体4

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High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings

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Journal of Advanced Ceramics 2022年第6期11卷 961-973页

作者： debao liu Baolu SHI Liyan GENG Yiguang WANG Baosheng XU Yanfei chen Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China Shanghai Space Propulsion Technology Research Institute Shanghai 201109China

The high-entropy rare-earth zirconate((La_(0.2)Nd_(0.2)Sm_(0.2)Gd_(0.2)Yb_(0.2))_(2)Zr_(2)O_(7),5RE_(2)Zr_(2)O_(7)HEREZs)ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction *** microstructure,crystal structure,phase composition,and thermophysical and mechanical properties of the samples were systematically investigated through various *** indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal *** as-prepared samples also demonstrate low thermal conductivity(0.9–1.72 W·m^(−1)·K^(−1)at 273–1273 K)and high coefficient of thermal expansion(CTE,10.9×10^(−6)K^(−1)at 1273 K),as well as outstanding mechanical properties including large young’s modulus(E=186–257 GPa)and high fracture toughness(KIC).Furthermore,the formation possibility of the as-prepared samples was verified through the first-principles calculations,which suggested the feasibility to form the 5RE_(2)Zr_(2)O_(7)HE-REZs in the thermodynamic ***,in view of the excellent multifunctional properties exhibited by the as-prepared 5RE_(2)Zr_(2)O_(7)HE-REZs,they have great potential applications in next-generation thermal-barrier coatings(TBCs).

关键词： high-entropy rare-earth zirconates(HE-REZs) first-principles calculations thermal conductivity thermal stability young’s modulus thermal-barrier coatings(TBCs)

Influencing Factors and Clustering Characteristics of COVID-19:A Global Analysis

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Big Data Mining and Analytics 2022年第4期5卷 318-338页

作者： Tianlong Zheng Chunli Zhang Yueting Shi debao chen Sheng liu School of Computer Science and Technology Huaibei Normal UniversityHuaibei 235000China School of Economics and Management Tiangong UniversityTianjin 300000China

The unprecedented coronavirus disease 2019(COVID-19)pandemic is still raging(in year 2021)in many countries *** response strategies to study the characteristics and distributions of the virus in various regions of the world have been developed to assist in the prevention and control of this *** statistics and regression analysis on COVID-19 data from different countries were conducted in this study to compare and evaluate various regression *** showed that the extreme random forest regression(ERFR)model had the best performance,and factors such as population density,ozone,median age,life expectancy,and Human Development Index(HDI)were relatively influential on the spread and diffusion of COVID-19 in the ERFR *** addition,the epidemic clustering characteristics were analyzed through the spectral clustering *** visualization results of spectral clustering showed that the geographical distribution of global COVID-19 pandemic spread formation was highly clustered,and its clustering characteristics and influencing factors also exhibited some consistency in *** study aims to deepen the understanding of the international community regarding the global COVID-19 pandemic to develop measures for countries worldwide to mitigate potential large-scale outbreaks and improve the ability to respond to such public health emergencies.

关键词： data analysis extreme random forest regression spectral clustering HDI COVID-19

山东、广西地区新型鹅细小病毒全基因组扩增及遗传进化分析

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中国家禽 2024年第6期46卷 44-55页

作者：乔丹丹刘婷隽陈全刚李德宝周婕董淑红胡安康徐州医科大学实验动物中心江苏徐州221004 徐州生物工程职业技术学院动物工程学院江苏徐州221006

为监测新型鹅细小病毒(Novel goose parvovirus,NGPV)的流行和变异情况,研究采集了山东和广西部分地区的鸭短喙综合征病料进行病原检测、全基因组扩增及序列比对分析。结果显示:共分离两株NGPV,山东分离株命名为SD202304,广西分离株命名... 详细信息

为监测新型鹅细小病毒(Novel goose parvovirus,NGPV)的流行和变异情况,研究采集了山东和广西部分地区的鸭短喙综合征病料进行病原检测、全基因组扩增及序列比对分析。结果显示:共分离两株NGPV,山东分离株命名为SD202304,广西分离株命名为GX202304,两株病毒与2021年NGPV分离株HNXY21亲缘关系最近,全基因组序列相似性为99.1%;GX202304株末端重复序列(Inverted terminal repeat,ITR)有一段未见报道的51 bp基因插入;VP3编码氨基酸序列比对显示,在第290位GX202304株和SD202304株有一个苏氨酸到丙氨酸的突变,这是NGPV近年来发生的新变异位点。研究表明,从山东、广西地区分离到的两株NGPV存在51 bp新的基因插入片段和VP3新的突变位点,结果为我国NGPV感染的防控提供科学依据。

关键词：新型鹅细小病毒全基因组序列鸭变异

In vitro and in vivo biocompatibility of Mg–Zn–Ca alloy operative clip

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Bioactive Materials 2019年第1期4卷 236-244页

作者： Pengfei Ding Yuanchao liu Xianghui He debao liu minfang chen School of Materials Science and Engineering Tianjin University of TechnologyTianjin300384China Tianjin Medical University General Hospital Department of General SurgeryTianjin300384300070China National Demonstration Center for Experimental Function Materials Education Tianjin University of TechnologyTianjin300384China Tianjin Key Laboratory for Photoelectric Materials and Devices Tianjin300384China

At present,titanium(Ti)and its alloys are most commonly use in hemostasis clip clinical ***,the Ti Clip cannot be absorbed in human body and produce artifacts on computed tomography(CT),and induce clinically relevant hypersensitivity in *** order to overcome the drawbacks of the non-degradable Ti clips,an Mg-Zn-Ca alloy operative clip was fabricated by combining hot extrusion and blanking *** vitro and in vivo biocompatibility of Mg-Zn-Ca alloy operative clip were evaluated by L-929 Cells and SD rat model *** was found that Mg-Zn-Ca alloy exhibited non-cytotoxic to L929 *** vivo implantation showed that the newly designed Mg-Zn-Ca clip can successfully ligated carotid artery and no blood leakage occurred *** the period of the clip degradation,a small amount of H2 gas formation and no tissue inflammation around the clips were *** degradation rate of the clip near the heart ligated the arteries faster than that of clip far away the heart due do the effect of arterial *** analysis and various blood biochemical parameters in rat serum samples collected at different times after clip implantation showed no tissue inflammation around the clips.

关键词： Mg-Zn-Ca alloy Biodegradable hemostatic clip In vitro and in vivo biocompatibility Carotid artery

海南省某三甲医院2021—2022年脑膜败血伊丽莎白金菌感染的临床特征及耐药性分析

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中国热带医学 2024年第1期24卷 87-91页

作者：闫建慧王燕萍刘海珍陈晓丹冯萃陈志乐左敏芳周兴业许华文海南医学院第二附属医院感控科海南海口570311 海南医学院第二附属医院重症医学科一区海南海口570311

目的探讨脑膜败血伊丽莎白金菌(Elizabethkingia meningoseptica,EM)感染的临床特征及耐药性,为预防EM医院感染和指导临床合理使用抗菌药物提供依据。方法回顾性调查2021—2022年海南省某三甲医院67例EM感染患者,分析其临床特征和菌株... 详细信息

目的探讨脑膜败血伊丽莎白金菌(Elizabethkingia meningoseptica,EM)感染的临床特征及耐药性,为预防EM医院感染和指导临床合理使用抗菌药物提供依据。方法回顾性调查2021—2022年海南省某三甲医院67例EM感染患者,分析其临床特征和菌株的耐药性。结果67例EM感染患者以≥60岁男性为主,主要来源于重症医学科一区(34.33%,23/67),其次为呼吸内科和急诊科(19.40%,13/67);标本主要分离自呼吸道标本(86.57%,58/67),其中痰液占49.25%(33/67)、肺泡灌洗液占37.31%(25/67)。EM感染患者的基础疾病主要为呼吸系统疾病(49.25%,33/67),多数患者住院时间长,且有侵入性操作,其中有机械通气者占94.03%(63/67),置入导尿管者占95.52%(64/67),中心静脉插管者占97.01%(65/67)。67例患者经治疗后,好转率为40.30%(27/67)。药敏结果显示,EM对头孢哌酮舒巴坦的耐药率达98.39%(61/62),而对复方新诺明、多西环素、美满霉素及哌拉西林他唑巴坦有较高的敏感性,敏感率均在90%以上。结论EM感染患者主要为老年男性,并伴有一定的基础疾病,患者住院时间长,且大多有侵入性操作。EM标本主要来源于重症医学科,主要分离自患者的呼吸道标本。该菌对头孢哌酮舒巴坦的耐药率较高,对复方新诺明、多西环素、美满霉素及哌拉西林他唑巴坦有较高的敏感性,临床可优先考虑使用。

关键词：脑膜败血伊丽莎白金菌医院感染临床特征耐药性海南

In vivo degradability and biocompatibility of a rheo-formed Mg–Zn–Sr alloy for ureteral implantation

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Journal of Magnesium and Alloys 2022年第6期10卷 1631-1639页

作者： Di Tie Renguo Guan Huinan liu minfang chen Sviatlana A.Ulasevich Ekaterina V.Skorb Patricia Holt-Torres Xiaopeng Lu Norbert Hort Engineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Department of Bioengineering University of CaliforniaRiversideCA 92521USA School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China Infochemistry Scientific Center ITMO UniversitySt.Petersburg 192007Russia Magnesium Innovation Center-MAGIC Helmholtz Zentrum GeesthachtGeesthacht D-21502Germany

The introduction of biodegradable implant materials has significantly improved the postoperative subjective feelings of patients within the past few decades,among which magnesium alloy is widely considered a favorable choice as its appropriate biodegradability and evident antibacterial ***,we reveal a semisolid rheo-formed Mg–Zn–Sr alloy ureteral implant that displayed suitable degradability and biocompatibility in a pig *** non-dendritic microstructure was observed in the rheo-formed alloy,which led to ca.47%increase in ultimate tensile strength(from 195.0 MPa to 288.1 MPa)and more homogeneous degradation process compared with the untreated *** post-interventional inflammation or pathological changes of the test animals were observed during the implantation period,and the corrosion rate(0.22±0.04 mm·y^(-1))perfectly fitted the clinical ureteral stent indwelling *** urine bacteria numbers decreased from 88±13 CFU·mL^(-1)at 7 weeks post operation to 59±8 CFU·mL^(-1)at 14 weeks post operation,which confirmed the evident antibacterial activity of the *** study demonstrates that the Mg–Zn–Sr alloy is clinically safe for urinary system,enabling its efficacious use as ureteral implant materials.

关键词： In vivo Biodegradability Biocompatibility Mg–Zn–Sr alloy Ureteral implant