G Y Sun

Publications (7)5.59 Total impact

• Article: Design, synthesis, and characterization of bulk metallic glass composite with enhanced plasticity

  G. Y. Sun, G. Chen, G. L. Chen
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  ABSTRACT: A Zr-based bulk metallic glass (BMG) in situ composite with a designed composition of Zr60Ti14.67Nb5.33Cu5.56Ni4.44Be10 was prepared based on both modifying alloy composition and controlling solidification process. The composite contains high volume fraction of coarsen bcc β-Zr(Ti, Nb) solid solution. The β phase particles are short rod-like, worm-like, and nearly spherical in morphology rather than typical dendrite structure, their volume fraction and average diameter were estimated to be about 55% and 20μm, respectively. The composite displays a large fracture strain up to 22.3% under uniaxial compression at room temperature. The coarse β phase and its high volume fraction were thought to be responsible for the excellent plastic deformability of the present composite.
  Journal of Materials Science 05/2012; 46(15):5216-5220. · 2.02 Impact Factor
• Article: Identification of a novel HLA-DRB1 allele (HLA-DRB1*111902*).

  D Li, H F Gao, X Liu, D Jiang, Z Li, Y H Liu, Y Z Jiang, L Li, G X Lan, C Z Zhao, T Guo, B Cai, D Wang, G Y Sun, D Zhang, D P Lu
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  ABSTRACT: In this paper, we report a new HLA-DRB1 allele identified in a male acute myeloid leukaemia Chinese patient. This sample was initially typed as DRB1*11XX using commercial polymerase chain reaction-sequence-specific primers kit. When it was typed using a chip-based sequence-specific oligonucleotide technique, a novel hybridization pattern that does not match any known alleles was observed. Through sequencing, we have identified this allele as a new HLA-DRB1 allele, which was later named HLA-DRB1*111902 by the WHO Nomenclature Committee. The sequence of this new allele differs from DRB1*111901 by one nucleotide (from G to C) at 203nt of exon 2 but does not cause any amino acid substitution.
  Tissue Antigens 08/2005; 66(1):67-8. · 2.59 Impact Factor
• Source

  Available from: web.missouri.edu

  Article: Low energy laser light (632.8 nm) suppresses amyloid-β peptide-induced oxidative and inflammatory responses in astrocytes

  X. Yang, S. Askarova, W. Sheng, J.K. Chen, A.Y. Sun, G.Y. Sun, G. Yao, J.C.-M. Lee
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  ABSTRACT: Oxidative stress and inflammation are important processes in the progression of Alzheimer's disease (AD). Recent studies have implicated the role of amyloid β-peptides (Aβ) in mediating these processes. In astrocytes, oligomeric Aβ induces the assembly of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complexes resulting in its activation to produce anionic superoxide. Aβ also promotes production of pro-inflammatory factors in astrocytes. Since low energy laser has previously been reported to attenuate oxidative stress and inflammation in biological systems, the objective of this study was to examine whether this type of laser light was able to abrogate the oxidative and inflammatory responses induced by Aβ. Primary rat astrocytes were exposed to Helium–Neon laser (λ=632.8 nm), followed by the treatment with oligomeric Aβ. Primary rat astrocytes were used to measure Aβ-induced production of superoxide anions using fluorescence microscopy of dihydroethidium (DHE), assembly of NADPH oxidase subunits by the colocalization between the cytosolic p47phox subunit and the membrane gp91phox subunit using fluorescent confocal microscopy, phosphorylation of cytosolic phospholipase A2 cPLA2 and expressions of pro-inflammatory factors including interleukin-1β (IL-1β) and inducible nitric-oxide synthase (iNOS) using Western blot Analysis. Our data showed that laser light at 632.8 nm suppressed Aβ-induced superoxide production, colocalization between NADPH oxidase gp91phox and p47phox subunits, phosphorylation of cPLA2, and the expressions of IL-1β and iNOS in primary astrocytes. We demonstrated for the first time that 632.8 nm laser was capable of suppressing cellular pathways of oxidative stress and inflammatory responses critical in the pathogenesis in AD. This study should prove to provide the groundwork for further investigations for the potential use of laser therapy as a treatment for AD.
  Neuroscience.
• Article: Innovative processing and property improvement of metallic glass based composites

  G.Y. Sun, G. Chen, C.T. Liu, G.L. Chen
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  ABSTRACT: An innovative method was developed based on controlled solidification in the liquid–solid two-phase region to produce spherical crystalline particles dispersed in the amorphous matrix. This new processing method can greatly improve both ductility and strength of bulk metallic glass composites.
  Scripta Materialia.
• Article: Analysis of elastic–plastic problems using edge-based smoothed finite element method

  X.Y. Cui, G.R. Liu, G.Y. Li, G.Y. Zhang, G.Y. Sun
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  ABSTRACT: In this paper, an edge-based smoothed finite element method (ES-FEM) is formulated for stress field determination of elastic–plastic problems using triangular meshes, in which smoothing domains associated with the edges of the triangles are used for smoothing operations to improve the accuracy and the convergence rate of the method. The smoothed Galerkin weak form is adopted to obtain the discretized system equations, and the numerical integration becomes a simple summation over the edge-based smoothing domains. The pseudo-elastic method is employed for the determination of stress field and Hencky's total deformation theory is used to define effective elastic material parameters, which are treated as field variables and considered as functions of the final state of stress fields. The effective elastic material parameters are then obtained in an iterative manner based on the strain controlled projection method from the uniaxial material curve. Some numerical examples are investigated and excellent results have been obtained demonstrating the effectivity of the present method.
  International Journal of Pressure Vessels and Piping 86(10):711-718. · 0.99 Impact Factor
• Article: Marker enzymes, phospholipids and acyl group composition of a somal plasma membrane fraction isolated from rat cerebral cortex: a comparison with microsomes and synaptic plasma membranes

  G.Y. Sun, H-M. Huang, J.A. Kelleher, E.B. Stubbs, A.Y. Sun
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  ABSTRACT: Subjecting brain homogenates to differential speed and sucrose density gradient centrifugation resulted in the isolation of a membrane fraction from the post-mitochondrial supernatant with properties and marker enzyme profiles typical of plasma membranes. This membrane fraction is compared with the microsomes and the synaptic plasma membranes isolated from synaptosomes. Like the synaptic plasma membranes, membranes obtained from the post-mitochondrial supernatant were enriched five-fold in 5′-nucleotidase activity. However, the latter membranes were lower in (Na+, K+)-ATPase activity and higher in NADPH-cytochrome C reductase activity as compared to the synaptic plasma membranes. The post-mitochondrial plasma membranes were also different from the microsomes in their respective marker enzyme activities. Electron microscopic examination indicated largely membranous vesicles for both plasma membrane fractions with little contamination by myelin, mitochondra and intact synaptosomes. The phospholipid and acyl group profiles of the two plasma membrane fractions were surprisingly similar, but they were different from the characteristic profiles of myelin and mitochondria. It is concluded that plasma membranes isolated from the post-mitochondrial supernatant fraction are derived largely from neuronal and glial soma and are thus designated the somal plasma membrane fraction.
  Neurochemistry International.
• Article: Wear resistance of NiTi alloy after surface mechanical attrition treatment

  T. Hu, C.S. Wen, G.Y. Sun, S.L. Wu, C.L. Chu, Z.W. Wu, G.Y. Li, J. Lu, K.W.K. Yeung, Paul K. Chu
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  ABSTRACT: An ultrafine grain layer consisting of nanocrystallites as well as submicrometer grains is produced on NiTi shape memory alloy by surface mechanical attrition treatment (SMAT) and the effects of the ultrafine grain layer on the tribological properties are investigated under dry sliding conditions. Compared to the coarse grain (CG) NiTi, the SMAT NiTi has smaller friction coefficients and improved wear resistance at applied loads from 5 to 15 N due to the grain refinement effect. Examination of the worn surfaces indicates that materials delamination and particles co-exist on both the CG and SMAT NiTi samples. Our results indicate that delamination is the main wear mechanism on CG NiTi whereas abrasive particles dominate the wear process on SMAT NiTi.
  Surface and Coatings Technology.