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Diameter-dependent in vitro performance of biodegradable pure zinc wires for suture application

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Journal of Materials Science & Technology 2019年第8期35卷 1662-1670页

作者： H. Guo R.H. Cao Y.F. Zheng J. Bai F. Xue C.L. Chu State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China School of Materials Science and Engineering Southeast University Nanjing 211189 China Key Laboratory for Advanced Metallic Materials Southeast University Nanjing 211189 China

In this study, biodegradable pure zinc wires with 3.0 mm and 0.3 mm in diameter were prepared via hot-extrusion and subsequent cold-drawing process respectively. The microstructure, mechanical performance, corrosion behavior, in vitro cytocompatibility and antibacterial effect were comparatively *** cold-drawing, the mechanical property, especially the elongation of the ф0.3 mm pure Zn wire was improved significantly compared with the ф3.0 mm pure Zn wire. The in vitro corrosion study including immersion and electrochemical test showed acceptable corrosion resistance of these two materials in Hank's solution. The in vitro Human Umbilical Vein Endothelial Cells(HUVECs) viability assay showed obviously different results, in which the ф0.3 mm pure Zn wire demonstrated favorable cytocompatibility, while the ф3.0 mm wire exhibited severe cytotoxic effect with 100% extract concentration. Both of them exhibited partly antibacterial effect on S. aureus. These results demonstrated the feasibility of the prepared 0.3 mm pure Zn wire as the potential suture material with good absorbability.

关键词： Pure zinc Wire Biodegradable metal Suture

Photo-induced transformations of Hg(Ⅱ) species in the presence of Nitzschia hantzschiana,ferric ion,and humic acid

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Journal of Environmental Sciences 2010年第1期22卷 76-83页

作者： Lin Deng Nansheng Deng Liwei Mou Fangtong Zhu Department of Municipal Engineering Southeast University Nanjing 210096 China School of Resources and Environmental Science Wuhan University Wuhan 430072 China

Effects of algae Nitzschia hantzschiana, Fe（Ⅲ） ions, humic acid, and pH on the photochemical reduction of Hg（Ⅱ） using the irradiation of metal halide lamps （λ〉 365 nm, 250 W） were investigated. The photoreduction rate of Hg（Ⅱ） was found to increase with increasing concentrations of algae, Fe（Ⅲ） ions, and humic acid. Alteration of pH value affected the photoreduction of Hg（Ⅱ） in aqueous solution with or without algae. The photoreduction rate of Hg（Ⅱ） decreased with increasing initial Hg（Ⅱ） concentration in aqueous solution in the presence of algae. The photochemical kinetics of initial Hg（Ⅱ） and algae concentrations on the photoreduction of Hg（Ⅱ） were studied at pH 7.0. The study on the total Hg mass balance in terms of photochemical process revealed that more than 42% of Hg（Ⅱ） from the algal suspension was reduced to volatile metallic Hg under the conditions investigated.

关键词： photoreduction Nitzschia hantzschiana Hg(Ⅱ) Fe(Ⅲ) humic acid

Excited State Properties of Fucoxanthin Aggregates

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Chemical Research in Chinese Universities 2019年第4期35卷 627-635页

作者： ZUO Jialing TAN Liming XU Yi MA Yingchao DONG Jia WANG Peng ZHANG Jianping Department of Chemistry Renmin University of China Beijing 100872 P. R. China

The structure and excited state properties of the H- and J-aggregates of the marine carbonyl carotenoid, fucoxanthin(Fx), were studied by various spectroscopic methods, and compared with those of Fx monomers in polar organic solvents. The fluorescent analysis indicated tliat the higher vibronic states of S2 contribute more to populating the S1 state, from which fluorescent emission mainly originates. Resonance Raman and density functional theory calculations confirmed the ‘card-packed' and chead-to-taiF structures of the H- and J-aggregates of Fx, respectively. An fs time-resolved absorption study proved the coexistence of Si and intramolecular charge transfer relaxation pathways upon excitation to the S2 state for both tlie monomers and aggregates.

关键词： Fucoxanthin aggregate Resonance Raman fs Time-resolved absorption Excited state property Singlet fission

In vitro and in vivo investigation on biodegradable Mg-Li-Ca alloys for bone implant application

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Science China Materials 2019年第2期62卷 256-272页

作者： Dandan Xia Yang Liu Siyi Wang Rong-Chang Zeng Yunsong Liu Yufeng Zheng Yongsheng Zhou Department of Prosthodontics Peking University School and Hospital of Stomatology Department of Materials Science and Engineering College of Engineering Peking University College of Materials Science and Engineering Shandong University of Science and Technology National Engineering Laboratory for Digital and Material Technology of Stomatology National Clinical Research Center for Oral Diseases Beijing Key Laboratory of Digital Stomatology

Magnesium alloys show promise for application in orthopedic implants, owing to their biodegradability and biocompatibility. In the present study, ternary Mg-(3.5,6.5 wt%) Li-(0.2, 0.5, 1.0 wt%) Ca alloys were developed. Their mechanical strength, corrosion behavior and cytocompatibility were studied. These alloys showed improved mechanical strength than pure Mg and exhibited suitable corrosion resistance. Furthermore, Mg-3.5Li-0.5Ca alloys with the best in vitro performance were implanted intramedullary into the femurs of mice for 2 and 8 weeks. In vivo results revealed a significant increase in cortical bone thickness around the Mg-3.5Li-0.5Ca alloy rods, without causing any adverse *** blotting and immunofluorescence staining of β-catenin illustrated that Mg-3.5Li-0.5Ca alloy extracts induced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells(hBMMSCs) through the canonical Wnt/β-catenin pathway. Our studies demonstrate that Mg-3.5Li-0.5Ca alloys hold much promise as candidates for the facilitation of bone implant application.

关键词： Mg-Li-Ca ahoy cytocompatibility biocompatibility human bone marrow-derived mesenchymal stem cells osteogenic differentiation

A Seismically Triggered Landslide in the Niujuan Valley near the Epicenter of the 2008 Wenchuan Earthquake

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Journal of Earth Science 2010年第6期21卷 901-909页

作者：韦方强 Sergey Chernomorets Konstantin Aristov Dmitry Petrakov Olga Tutubalina 苏鹏程江玉红徐爱淞 Alexey Petrasov Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of Sciences Institute of Mountain Hazards and Environment Chinese Academy of Sciences Faculty of Geography Moscow State University Sergeev Institute of Environmental Geoscience Russian Academy of Sciences

The Wenchuan （汶川） earthquake on 12 May 2008 induced a large number of landslides, collapses, and rockfalls along the Longmenshan （龙门山） fault. The landslide in Niujnau （牛圈） Valley （named Niujuan landslide）, close to the epicenter, is one that travelled a long distance with damaging consequences. Using QuickBird satellite images and GIS tools, the seismogenic mass movements are analyzed, and the movement phases, travel path, and post-catastrophic processes of Niujuan landslide are described and discussed. Image interpretation and a GPS survey showed that the mass movements denuded 37% of the research area. The Niujuan landslide moved 1 950 m along the Lianhuaxingou （莲花心沟） stream, transformed to a debris avalanche, and accumulated in the downstream bed of Niujuan Valley, where they formed a dam 30 m in height, blocking the Niujuan stream and creating a barrier lake basin with 0.11 million m3 storage capacity. Subsequent to the Ninjuan landslide, debris flowshave been more active in Lianhuaxingou and Niujuan valleys because of the accumulated mass of debris.

关键词： Wenchuan earthquake landslide debris flow debris avalanche.

Triplet excitation dynamics of β-carotene studied in three solvents by ns flash photolysis spectroscopy

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Chinese Chemical Letters 2017年第1期28卷 83-88页

作者： Ying Jia Ying Shi Peng Wang Jian-Ping Zhang Department of Chemistry Renmin University of China Beijing 100872 China

Upon anthracene-sensitizing, triplet excitation dynamics of β-carotene（β-Car） were studied in nhexane, in methanol, and in acetonitrile, respectively, by ns flash photolysis spectroscopy. In n-hexane,only the bleaching of the ground state absorption（GSB） and the excitation triplet（^3Car＊） absorption were observed, and there were no cationic species detected. In both methanol and acetonitrile, similar excitation dynamics were observed, i.e.,^3Car＊ having a similar lifetime to that in n-hexane, and the immediate generation of the cation dehydrodimer（^#[Car]2^＋） upon excitation following transformation into the radical cation Car＊^＋, since Car＊^＋ has much longer lifetime in acetonitrile than in methanol. The results prove that both solvent and carotenoid structure determine the triplet excitation mechanism.

关键词： β-Carotene Triplet excitation dynamics Solvent effect ns Flash photolysis

Hydrochemical and Isotopic Evidence of Origin of Thermal Karst Water at Taiyuan,Northern China

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Journal of Earth Science 2009年第5期20卷 879-889页

作者：马腾王焰新郭清海闫春淼马瑞黄征 Key Laboratory of Biogeology and Environmental Geology of the Ministry of Education China University of Geosciences Hubei Institute of Environmental Science

Thermal karst groundwaters with temperatures ranging from 32.8 to 62.5 ℃ were found at Taiyuan（太原） City,the capital of Shanxi（山西） *** identify the origin of the thermal groundwater,the following tracers were used in this study：δD,δ18O,4He,3He/4He,and major chemical constituents in *** and isotopic data indicate that the thermal groundwaters in the basin area are a mixture of thermal waters from the West Mountain and those from the East ***,the 4He and 4Heexc concentrations of the thermal groundwater samples are usually lower than those of the cold groundwater samples,and there is an evidently negative correlation between the temperature and the 4He concentration in thermal groundwaters from the West Mountain and the ba-sin,which means that with the increase in temperature,the He concentration increases in the vapor phase and decreases in the aqueous *** the plot of 3He/4He vs.4He/20Ne of all water samples：air,crust,and mantle,all thermal groundwater samples are distributed near the line between the point of air and that of crust,suggesting that atmospheric and crustal helium is the main source for that in thermal *** other words,there are no mantle-derived fluids mixed in the thermal groundwaters.

关键词： thermal groundwater origin,hydrochemistry isotope, ^3He/^4He Talyuan.

Systematic in vitro and in vivo study on biodegradable binary Zn-0.2 at%Rare Earth alloys(Zn-RE:Sc,Y,La-Nd,Sm-Lu)

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Bioactive Materials 2023年第6期24卷 507-523页

作者： Shaokang Du Yunong Shen Yufeng Zheng Yan Cheng Xiaoxue Xu Dafu Chen Dandan Xia Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing100871China School of Materials Science and Engineering Peking UniversityBeijing100871China School of Biomedical Engineering Faculty of Engineering and Information TechnologyUniversity of Technology SydneyNSW2007Australia Laboratory of Bone Tissue Engineering Beijing Laboratory of Biomedical MaterialsBeijing Research Institute of Traumatology and OrthopaedicsBeijing Jishuitan HospitalBeijing100035China Department of Dental Materials Peking University School and Hospital of Stomatology&National Center of Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical Devices&Beijing Key Laboratory of Digital Stomatology&Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health&NMPA Key Laboratory for Dental MaterialsBeijing 100081China

Biomedical implants and devices for tissue engineering in clinics,mainly made of polymers and stiff metallic materials,require possibly secondary surgery or life-long *** metals for biomedical implants and devices exhibit huge potential to improve the prognosis of *** this work,we developed a new type of biodegradable binary zinc(Zn)alloys with 16 rare earth elements(REEs)including Sc,Y,La to Nd,and Sm to Lu,*** effects of REEs on the alloy microstructure,mechanical properties,corrosion behavior and in vitro and in vivo biocompatibility of Zn were systematically investigated using pure Zn as *** Zn-RE alloys generally exhibited improved mechanical properties,and biocompatibilities compared to pure Zn,especially the tensile strength and ductility of Zn-RE alloys were dramatically *** the Zn-RE alloys,different REEs presented enhancement effects at varied extent.Y,Ho and Lu were the three elements displaying greatest improvements in majority of alloys properties,while Eu,Gd and Dy exhibited least ***,the Zn-RE alloys were comparable with other Zn alloys and also exhibited superior properties to Mg-RE *** in vivo experiment using Zn-La,Zn-Ce,and Zn-Nd alloys as tibia bone implants in rabbit demonstrated the excellent tissue biocompatibility and much more obvious osseointegration than the pure Zn control *** work presented the significant potential of the developed Zn-RE binary alloys as novel degradable metal for biomedical implants and devices.

关键词： Biodegradable metals Zn-Rare Earth alloys Mechanical property Biodegradation behavior Biocompatibility

The surface properties of Malan loess and its application to removing Cr(Ⅲ) from contaminated water

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Chinese Journal Of Geochemistry 2010年第1期29卷 94-99页

作者： MA Teng WANG Yanxin LUO Wei HUANG Zheng HE Xin HE Jun TIAN Chunyan Key Laboratory of Biogeology and Environmental Geology of Ministry of Education （China University of Geosciences） Wuhan 430074 China Guizhou Institute of Geo-Environment Monitoring Guiyang 550004 China

Loess has unique compositions and structural characteristics and can be used for environmental *** between the surface characteristics of the Malan loess from the suburbs of Taiyuan,Shanxi Province before and after reaction with Cr(Ⅲ) solution were studied by SEM/EDS,IR and *** results showed that the Malan loess has a strong ability to remove Cr(Ⅲ) from the *** surface characteristics of loess include an effect on Cr(Ⅲ) in solution,as supported by the strong test evidence including the disappearance of Cr peak in the EDS spectrum,the disappearance of carbonate characteristic peaks in the infrared spectrogram,and the positive correlation between Fe and Cr peaks.

关键词：马兰黄土铬(Ⅲ) 表面性能除污染红外光谱图应用溶液反应 X射线衍射