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Hyperhomocysteinemia independently causes and promotes atherosclerosis in LDL receptor-deficient mice

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Journal of Geriatric Cardiology 2014年第1期11卷 74-78页

作者： Hang-Yuan guo fu-Kang xu Hai-Tao LV Long-Bin LIU Zheng JI Xiao-Ya ZHAI Wei-Liang TANG Ju-Fang CH Department of Cardiology Shaoxing Hospital of Zhejiang University Shaoxing 312000 Zhejiang Province China

Background Hyperhomocysteine is an independent risk factor of coronary heart disease （CHD）. However, whether hyperhomocys teine affects the progression of atherosclerosis is unclear. In the present study, we examined the effect of hyperhomocysteine on the forma tion of atherosclerosis in low-density lipoprotein receptor-deficient （LDLr ） mice. Methods Forty-eight 7-week-old LDLr/ mice were assigned to the following groups： mice fed a standard rodent diet （control group）, mice fed a high-methionine diet （high-methionine group）, mice fed a high-fat diet （high-fat group）, and mice fed a diet high in both methionine and fat （high-methionine and high-fat group）. At the age of 19, 23, and 27 weeks, four mice at each interval in every group were sacrificed. Results At the end of the study, mice did not show atherosclerotic lesions in the aortic sinus and aortic surface until 27 weeks old in the control group. However, atherosclerotic lesions developed in the other three groups at 19 weeks. The amount of atherosclerotic lesions on the aortic surface was lower in the high-methionine group than in the high-fat group （P 〈 0.001）. Atherosclerotic lesions on the aortic surface in the high-methionine and high-fat group were the most severe. The mean area of atherosclerotic lesions in the aortic sinus compared with atherosclerotic lesions on the aortic surface was lower in the high-methionine group than in the high-fat group （P 〈 0.001）. Atherosclerotic lesions in the aortic sinus in the high-methionine and high-fat group were the most severe. Conclusions Homocysteinemia accelerates atherosclerotic lesions and induces early atherosclerosis independently in LDLrmice. Reducing the level of homocysteinemia may be beneficial for prevention and treatment of CHD.

关键词： Atherosclerosis Homocysteine Low-density lipoprotein Hyperhomocysteinemia

Strong and ductile Al−Zn−Mg−Zr alloy obtained by equal angular pressing and subsequent aging

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Transactions of Nonferrous Metals Society of China 2022年第5期32卷 1428-1441页

作者： Lei TANG Xiao-yan PENG fu-qing JIANG Yao LI guo-fu xu School of Metallurgy and Materials University of BirminghamB152TTUnited Kingdom School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Metallic Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha 410083China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

An ultrafine-grained Al−Zn−Mg−Zr alloy with superior mechanical performance was obtained by high passes of equal angular pressing(ECAP)and subsequent *** 8 ECAP passes and aging,the yield strength(YS)and ultimate tensile strength(UTS)of the solid-solutioned alloy are significantly improved from(98±10)and(226±7)MPa to(405±9)and(427±9)MPa,respectively.A large elongation is also maintained((17.4±2.5)%).The microstructure features including grain refinement,morphology of precipitates,and dislocation density,were revealed with multiscale characterizations,including transmission electron microscopy,electron backscattered diffraction,and X-ray *** 8 passes of ECAP,the original coarse elongated grains are refined to a unique bimodal grain structure consisting of ultrafine equiaxed and lath-like ***,the effects of ECAP and subsequent aging on the strengthening contribution of a variety of strengthening mechanisms,such as dislocation strengthening and precipitation strengthening,were discussed in detail.

关键词： equal angular pressing Al−Zn−Mg−Zr alloy grain refinement strengthening mechanism

PCR-SSCP-DNA sequencing method in detecting PTEN gene mutation and its signifi cance in human gastric cancer

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World Journal of Gastroenterology 2008年第24期14卷 3804-3811页

作者： Chuan-Yong guo xuan-fu xu Jian-Ye Wu Shu-Fang Liu Department of Gastroenterology Tenth People's Hospital ofTongji University Shanghai 200072 China

AIM: To discuss the possible effect of PTEN gene mutations on occurrence and development of gastric cancer. METHODS: Fifty-three gastric cancer specimens were selected to probe PTEN gene mutations in genome of gastric cancer and paracancerous tissues using PCR-SSCP-DNA sequencing method based on microdissection and to observe the protein expression by immunohistochemistry technique. RESULTS: PCR-SSCP-DNA sequencing indicated that 4 kinds of mutation sites were found in 5 of 53 gastric cancer specimens. One kind of mutation was found in exons. AA-TCC mutation was located at 40bp upstream of 3’ lateral exon 7 (115946 AA-TCC). Such mutations led to terminator formation in the 297th codon of the PTEN gene. The other 3 kinds of mutation were found in introns,including a G-C point mutation at 91 bp upstream of 5’ lateral exon 5(90896 G-C),a T-G point mutation at 24 bp upstream of 5’ lateral exon 5 (90963 T-G),and a single base A mutation at 7 bp upstream of 5’ lateral exon 5 (90980 A del). The PTEN protein expression in gastric cancer and paracancerous tissues detected using immunohistochemistry technique indicated that the total positive rate of PTEN protein expression was 66% in gastric cancer tissue,which was significantly lower than that (100%) in paracancerous tissues (P < 0.005). CONCLUSION: PTEN gene mutation and expression may play an important role in the occurrence and development of gastric cancer.

关键词： Gastric cancer PTEN gene PCR-SSCP DNA sequencing Mutation

Influence of operation number on arc erosion behavior of Ag/Ni electrical contact materials

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Transactions of Nonferrous Metals Society of China 2022年第8期32卷 2681-2695页

作者： Run-zhang HUANG guo-fu xu Qiong WU Meng YUAN Chun-ping WU School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education Central South UniversityChangsha 410083China

Arc erosion behavior of Ag/Ni materials with different operation numbers was investigated by OM,3DOP and *** results indicated that the arc erosion of Ag/10Ni electrical contact material fabricated by sintering−extrusion technology was more and more serious with the operation numbers increasing from 1000 to *** the same operation numbers,the arc erosion on anode was more serious than that on ***,the pores preferred to emerge around the arc effect spot during the first 10000 *** the morphology of the molten silver on cathode and anode was different due to the action of gravity and arc ***,the relationships among arc energy,arc time,welding force,electric resistivity,temperature and mass change on contacts were discussed,which indicated that the mass loss on cathode was mainly caused by the fracture of molten bridge.

关键词： Ag/Ni electrical contact material operation number arc erosion arc parameter

Effects of minor Sc and Zr additions on mechanical properties and microstructure evolution of Al−Zn−Mg−Cu alloys

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Transactions of Nonferrous Metals Society of China 2020年第6期30卷 1429-1438页

作者： Quan-feng XIAO Ji-wu HUANG Ying-ge JIANG fu-qin JIANG Yun-feng WU guo-fu xu School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Metallic Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha 410083China

The effects of minor Sc and Zr additions on the mechanical properties and microstructure evolution of Al Zn Mg Cu alloys were studied using tensile tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ultimate tensile strength of the peak-aged Al Zn Mg Cu alloy is improved by about 105 MPa with the addition of 0.10% Zr. An increase of about 133 MPa is observed with the joint addition of 0.07% Sc and 0.07% Zr. For the alloys modified with the minor addition of Sc and Zr (0.14%), the main strengthening mechanisms of minor addition of Sc and Zr are fine-grain strengthening, sub-structure strengthening and the Orowan strengthening mechanism produced by the Al3(Sc,Zr) and Al3Zr dispersoids. The volume of Al3Zr particles is less than that of Al3(Sc,Zr) particles, but the distribution of Al3(Sc,Zr) particles is more dispersed throughout the matrix leading to pinning the dislocations motion and restraining the recrystallization more effectively.

关键词： Al Zn Mg Cu alloys Al3(Sc,Zr) Al3Zr dislocation motion recrystallization strengthening mechanism

Effect of non-isothermal aging on microstructure and properties of Al−5.87Zn−2.07Mg−2.42Cu alloys

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Transactions of Nonferrous Metals Society of China 2021年第10期31卷 2899-2908页

作者： Yao LI guo-fu xu Xiao-yan PENG Shi-chao LIU Ying DENG Xiao-peng LIANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education Central South UniversityChangsha 410083China

The evolution of microstructure and properties of Al−5.87Zn−2.07Mg−2.42Cu alloys during non-isothermal aging was *** mechanical properties of the alloy were tested by stretching at room *** results show that in the non-isothermal aging process,when the alloy is cooled to 140℃,the ultimate tensile strength of the alloy reaches a maximum value of 582 MPa and the elongation is 11.9%.The microstructure was tested through a transmission electron microscope,and the experimental results show that the GP zones andη'phases are the main strengthening *** the cooling stage,when the temperature dropped to 180℃,the GP zones were precipitated ***,the experimental results show that the main strengthening phase during non-isothermal aging isη'phases.

关键词： Al−Zn−Mg−Cu aluminum alloy non-isothermal aging η'phases mechanical properties

High temperature mechanical properties and microstructure of die forged Al-5.87Zn-2.07Mg-2.42Cu alloy

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Transactions of Nonferrous Metals Society of China 2020年第7期30卷 1771-1779页

作者： Yao LI guo-fu xu Xiao-yan PENG Shi-chao LIU Yu-hai DOU Xiao-peng LIANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Materials Science and Engineering Ministry of EducationChangsha 410083China Centre for Clean Environment and Energy Griffith UniversityGold CoastQLD 4222Australia

The high temperature mechanical properties(250 ℃) and microstructure of a die-forged Al-5.87 Zn-2.07 Mg-2.42 Cu alloy after T6 heat treatment were investigated. High temperature tensile tests show that as the temperature increases from room temperature to 250 ℃, the ultimate tensile strength of the alloy decreases from 638 to 304 MPa, and the elongation rises from 13.6% to 20.4%. Transmission electron microscopy(TEM) and electron backscattered diffraction(EBSD) were applied for microstructure characterization, which indicates that the increase of tensile temperature can lead to the coarsening of precipitates, drop of dislocation density, and increase of dynamic recovery. After tensile testing at 250 ℃, a sub-grain structure composed of a high fraction of small-angle grain boundary is formed.

关键词： Al-Zn-Mg-Cu alloy dynamic recovery high temperature mechanical properties microstructure

Comparison of nickle release and cytocompatibility between porous and dense NiTi alloy

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Transactions of Nonferrous Metals Society of China 2021年第12期31卷 3814-3820页

作者： Ben-quan YU Wen-hui YUAN Qiang xu Yun-fang-zi GU Ming-ming XIAO guo-fu xu Zhou LI Zhu XIAO Zi-an XIAO Department of Otolaryngology Head and Neck Surgery of Second Xiangya Hospital Central South UniversityChangsha 410011China School of Materials Science and Engineering Central South UniversityChangsha 410083China

The porous NiTi(pNiTi)samples were produced by sintering evaporation using Ti−50.8Ni(at.%)gasatomized *** samples were analyzed by metallographic microscope and X-ray dispersive spectroscopy(XRD).A comparison of nickel(Ni)release and cytocompatibility between pNiTi and dense NiTi(dNiTi)was *** results showed that the pNiTi has good mechanical *** releases from pNiTi in vitro and in vivo are more serious than those form *** proliferation and differentiation of cells cultured with the pNiTi extracting liquid are significantly worse,and the rate of early apoptosis is *** conclusion,pNiTi is mechanically similar to bone,but pNiTi releases more Ni and interferes with cell proliferation and differentiation.A significantly cautious approach should be adopted when using it as a medical implant.

关键词： porous nitinol alloy mechanical property nickel release cytocompatibility

液固两相流对A182F347不锈钢材料的磨损特性

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煤炭学报 2016年第11期41卷 2883-2888页

作者：偶国富刘旭金浩哲王超浙江理工大学多相流沉积-冲蚀试验室浙江杭州310018

以直径为150μm的Si O2和Al2O3混合物为磨料,在自制的旋转式液-固两相流冲蚀试验装置上研究冲击角度、冲击速度及浆体浓度对奥氏体不锈钢A182F347的冲蚀规律,结合试件表面的冲蚀形貌分析,揭示稀相液固两相流体系下奥氏体不锈钢A182F347... 详细信息

以直径为150μm的Si O2和Al2O3混合物为磨料,在自制的旋转式液-固两相流冲蚀试验装置上研究冲击角度、冲击速度及浆体浓度对奥氏体不锈钢A182F347的冲蚀规律,结合试件表面的冲蚀形貌分析,揭示稀相液固两相流体系下奥氏体不锈钢A182F347冲蚀机理。结果表明：4%~8%的浆体浓度下,冲击角度对试件的冲蚀规律近似,即在冲击角度为60°时出现磨损率峰值,峰值两侧区域磨损率逐渐降低;浆体浓度为6%,冲击速度从1.65 m/s增加至3.85 m/s时,试件磨损率呈指数增加;在高流速下,冲击角度为60°,浆体浓度小于6%时,试件磨损率受浆体浓度的影响较小,浆体浓度大于6%时,浓度越高,试件磨损率越大。在低流速下,浆体浓度大于8%时,试件磨损率受浆体浓度影响较小;A182F347的冲蚀磨损在低冲击角度下,以犁沟切削磨损为主,在高冲击角度下,以锻打变形磨损为主。建立的数学模型与试验结果较吻合。

关键词：液固两相流不锈钢A182F347 冲蚀磨损犁沟切削变形磨损