Influence of Asymmetric Rolling Process and Thickness Reduction on the Microstructure and Mechanical Properties of the Al–Mg-Si Alloy

Xuehong Xu,Yunlai Deng,Xiaobin Guo,Qinglin Pan 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The influence of the asymmetric rolling process (ASR) and thickness reduction on the microstructure and mechanical propertiesof Al–Mg–Si alloys is studied. The specimens of the ASR and higher thickness reduction show higher strength (both theultimate tensile strength and yield strength) and lower elongation (El). However, both the strength and El are reduced withthe increase of the rotation speed ratio (ω1/ω2) in the specimens treated by the ASR. The grain size, density of dislocations,volume fraction of deformation texture and number density of precipitates are the main reasons causing the difference instrength and El. The increment in strength is mainly due to the increase of deformation texture, density of dislocations duringthe cold rolling and number density of precipitates formed during subsequent ageing. The reduction of volume fractionof deformation texture and number density of precipitates are responsible for the decrease of the strength in the specimenstreated by the ASR. The high-density dislocations in turn provide little room for the accumulation of dislocations and thereforereduces the EI.

Circular RNA CREBBP modulates cartilage degradation by activating the Smad1/5 pathway through the TGFβ2/ALK1 axis

Xu Yiyang,Mao Guping,Long Dianbo,Deng Zengfa,Xin Ruobin,Zhang Ziji,Xue Ting,Liao Weiming,Xu Jie,Kang Yan 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Osteoarthritis, characterized by articular cartilage degradation, is the leading cause of chronic disability in older adults. Studies have indicated that circular RNAs are crucial regulators of chondrocyte development and are involved in the progression of osteoarthritis. In this study, we investigated the function and mechanism of a circular RNA and its potential for osteoarthritis therapy. The expression levels of circCREBBP, screened by circular RNA sequencing during chondrogenic differentiation in adipose tissue-derived stem cells, and TGFβ2 were significantly increased in the cartilage of patients with osteoarthritis and IL-1β-induced chondrocytes. circCREBBP knockdown increased anabolism in the extracellular matrix and inhibited chondrocyte degeneration, whereas circCREBBP overexpression led to the opposite effects. Luciferase reporter assays, rescue experiments, RNA immunoprecipitation, and RNA pulldown assays confirmed that circCREBBP upregulated TGFβ2 expression by sponging miR-1208, resulting in significantly enhanced phosphorylation of Smad1/5 in chondrocytes. Moreover, intra-articular injection of adeno-associated virus-sh-circCrebbp alleviated osteoarthritis in a mouse model of destabilization of the medial meniscus. Our findings reveal a critical role for circCREBBP in the progression of osteoarthritis and provide a potential target for osteoarthritis therapy.

Improvement of Anti-CD36 Antibody Detection via Monoclonal Antibody Immobilization of Platelet Antigens Assay by Using Selected Monoclonal Antibodies

Xu Xiuzhang,Chen Dawei,Ye Xin,Xia Wenjie,Shao Yuan,Deng Jing,Chen Yangkai,Ding Haoqiang,Liu Jing,Xu Yaori,Santoso Sentot,Fu Yongshui 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.1

Antibodies against human CD36 are responsible for several immune-mediated disorders. The detection of anti-CD36 antibodies using the standard monoclonal antibody (mAb) immobilization of platelet antigens (MAIPA) assay is hampered by a high frequency of false-negative results, most likely due to competitive inhibition of the mAb used as the capture antibody. We generated a panel of mouse mAbs against CD36 and seven hybridomas (GZ-3, GZ-13, GZ-70, GZ-143, GZ-413, GZ-507, and GZ-608), which were selected for MAIPA assays, as they reacted with mouse and human CD36. Fourteen anti-CD36 sera were assayed; all of which showed a positive reaction in a PakPlus (Immucor GTI Diagnostics, Inc., Waukesha, WI, USA) ELISA-based screening (optical density: 0.257–2.292). When the reference anti-CD36 mAb FA6-152 was used in the MAIPA assay, only 6/14 (42.9%) sera displayed a positive reaction. In contrast, anti-CD36 antibodies were detected in 13/14 (92.9%) sera when GZ-70 and GZ-608 mAbs were used. This significant improvement resulted in the identification of anti-CD36 antibodies by an antigen capture assay. Since patient’s platelets possibly carrying rare native antigens are used, this method will facilitate the identification of new platelet antibodies against CD36 that are involved in immune-mediated thrombocytopenia and other diseases, such as transfusion-related acute lung injury.

Dielectric properties of exfoliated graphite reinforced flouroelastomer composites

Xu, Deng,Sridhar, V.,Mahapatra, S. P.,Kim, Jin Kuk Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of applied polymer science Vol.111 No.3

<P>Dielectric relaxation behavior of nano graphite reinforced flouroelastomer composites has been studied as a function of variation in filler in the frequency range of 0.01–10<SUP>5</SUP> Hz. The effect of variation in filler loadings on the complex and real parts of impedance was distinctly visible which has been explained on the basis of interfacial polarization of fillers in a heterogeneous medium and relaxation dynamics of polymer chains in the vicinity of fillers. The electric modulus formalism has been utilized to further investigate the conductivity and relaxation phenomenon. The frequency dependence of AC conductivity has been investigated by using Percolation theory. The phenomenon of percolation in the composites has been discussed based on the measured changes in electric conductivity and morphology of composites at different concentrations of the filler. The percolation threshold as studied by DC conductivity occurred in the vicinity of 2.5–3.5 phr of filler loading. Scanning electron microscope microphotographs showed agglomeration of the filler above this concentration and formation of a continuous network structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009</P>

Fabrication and Cell Culturing on Carbon Nanofibers/Nanoparticles Reinforced Membranes for Bone-Tissue Regeneration

Xu Liang Deng,Xiao Ping Yang 한국탄소학회 2012 Carbon Letters Vol.13 No.3

Poly-L-lactic acid (PLLA), PLLA/hydroxyapatite (HA), PLLA/multiwalled carbon nanotubes (MWNTs)/HA, PLLA/trifluoroethanol (TFE), PLLA/gelatin, and carbon nanofibers (CNFs)/β-tricalcium phosphate (β-TCP) composite membranes (scaffolds) were fabricated by electrospinning and their morphologies, and mechanical properties were characterized for use in bone tissue regeneration/guided tissue regeneration. MWNTs and HA nanoparticles were well distributed in the membranes and the degradation characteristics were improved. PLLA/MWNTs/HA membranes enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion of gingival epithelial cells by 30%. Osteoblast-like MG-63 cells on the randomly fiber oriented PLLA/TEF membrane showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel fiber oriented membrane. Classical supersaturated simulated body fluids were modified by CO2 bubbling and applied to promote the biomineralization of the PLLA/gelatin membrane; this resulted in predictions of bone bonding bioactivity of the substrates. The β-TCP membranes exhibit good biocompatibility, have an effect on PDLC growth comparable to that of pure CNF membrane, and can be applied as scaffolds for bone tissue regeneration.

Effect of dielectric barrier discharge parameters on degradation efficiency of ethyl acetate

Deng, Xu,Lu, SiHeng,Zheng, Kun,Yu, ZhiMin Urban Science Institute 2019 도시과학 Vol.8 No.2

Using self-made coil dielectric barrier discharge reactor, the removal efficiency of ethyl acetate under simulated experimental parameters such as initial concentration of waste gas, total flow rate, relative humidity and voltage was investigated. The results show that the degradation rate of ethyl acetate increases with the increase of output voltage. When other conditions remain unchanged, the degradation rate decreases with the increase of initial concentration of ethyl acetate; with the increase of total flow rate, the degradation rate of ethyl acetate decreases; with the increase of relative humidity, the degradation rate first increases and then decreases, and when the relative humidity is 64%, the degradation efficiency is the highest.

Lovastatin derivative dehydrolovastatin ameliorates ulcerative colitis in mice by suppressing NF-κB and inflammatory cytokine expression

Xu Zhang,Qing-Hua Deng,Jian-Hua Deng,Sheng-Ju Wang,Qiu Chen 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.2

Ulcerative colitis (UC) is associated with intestinal immune imbalance and inflammatory response. Because dehydrolovastatin (DLVT), a derivative of lovastatin, has been recently shown to inhibit inflammation and relieve immune arthritis induced by chemical stimuli, we studied its effect and possible mechanism on UC induced by dextran sulfate sodium. The BALB/c mice were classified into six groups: normal control group, model group, DLVT high dose group, DLVT low dose group, salazosulfapyridine (SASP) group and lovastatin (LVT) group. The disease activity indices of UC and pathological changes were investigated. The myeloperoxidase (MPO) activity in colon tissue and inflammatory factors such as IL-6, IL-10, IL-17, and TNF- in the serum were analyzed by ELISA, while the expression of NF-B p65 protein in colon tissue was detected by immunohistochemistry and western blot. DLVT relieved the disease activity indices and pathological damage of the UC mice. Furthermore, DLVT significantly decreased MPO activity and improved the imbalance of inflammatory cytokines through inhibiting the expression of NF-B p65. Meanwhile, the positive drug of SASP has a similar effect to DLVT, but the effect of DLVT in both decreasing IL-17, TNF-, and increasing IL-10 was significantly stronger than that of SASP. These results suggest that DLVT may ameliorates the symptoms of UC.

Temperature Effect Analysis of Large Segment Factory Manufacturing Alignment of Steel Box Girder

Deng Fuqiang,Wang Jinfeng,Yang Songwei,Xu Linghua,Xu Rongqiao 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1

The construction of the cross-sea steel box girder bridge is gradually advancing and integrating, which particularly refl ects in the size of the bridge. The length of a single installation segment often exceeds 100 m. The alignment of the steel box girder is signifi cantly aff ected by the temperature eff ect during manufacturing. This paper investigates the impact of temperature gradient on corresponding alignment at the manufacturing stage for the large-segment steel box girder taking a large-span continuous steel box girder bridge as a case study. The inspection of temperature during the assembly procedure was carried out. After obtaining the data during welding, the infl uence of the temperature was evaluated using a fi nite element model. The results show that with the temperature gradient measured, the defl ection of the second suspension of the mid-span reaches 10.9 mm and the defl ection of the cantilever end reaches 17.1 mm, respectively. The deformation conforms to the code specifi cations when considering the infl uence of the temperature gradient eff ect. The corresponding pre-camber value should be set for the large segments assembled outdoor. At the same time, welding operation should be carried out under the preset temperature diff erence to partially eliminate the impact of temperature gradient.

Molecular Mechanism and Regulation of Carotenoid Biosynthesis in Citrus sinensis

Qiang Xu,Xiuxin Deng,Qing Liu,Jiancheng Zhang,Nengguo Tao,Wenjing Zhou,Zhiyong Pan,Juan Xu 한국원예학회 2008 한국원예학회 기타간행물 Vol.- No.-

A cam-quadrilateral mechanism for power transmission of a twin-rotor piston engine

Xiaojun Xu,Hao Deng,Cunyun Pan,Haijun Xu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3

A quadrilateral with four invariable lengths of sides has the characteristic of transforming the variation of the diagonal length to thevariation of its interior angle. Thus, the combination of two quadrilaterals with a cam forms the differential velocity drive mechanism(DVDM) of a novel twin-rotor piston engine (TRPE). The DVDM restricts the two coaxial rotors to rotate with periodical but nonuniformvelocity, and the volume of working chambers created by the adjacent vane pistons of the two rotors alternately expands and thencontracts. The volumetric change of working chambers is used to generate the four-stroke engine cycle. The kinematic model and thedetailed position, velocity, and acceleration analysis results of the TRPE are presented. The results show that this novel engine, associatedwith the advantages of higher uniformity of torque and power density due to multiple power strokes per revolution of the output shaft, hasa compact and totally balanced design.