Cytotoxicity of polymethyl methacrylate cement on primary cultured metastatic spinal cells

Ji Fang,Jieliang Shen,Wei Jiang,Wen Dong,Zhenming Hu,Zhenming Hu 대한독성 유전단백체 학회 2016 Molecular & cellular toxicology Vol.12 No.2

Polymethyl methacrylate (PMMA) bone cement has been commonly used for percutaneous injection into collapsed vertebral bodies due to malignant tumor. The purpose of this study was to investigate the possible mechanisms of PMMA’s cytotoxcity on primary cultured spinal metastastic cells (SMCs) in vitro. PMMA specimens were prepared in standard discs made of dough and polymerization stages, and the eluates were prepared following the ISO standard. Primary SMCs were obtained and isolated from 7 patients with spinal metastatic tumors undergoing vertebroplasty. Primary cultured SMCs were treated with PMMA specimens of different stages for 24 h, or co-cultured with extracted medium for successive 3 days. The temperatures in two locations from cement discs were recorded by K-type thermocouples. Furthermore, cell proliferation, apoptosis and cycles were determined by MTT and flow cytometry, respectively. The modulation of apoptotic proteins (bcl- 2, bax, caspase-3, caspase-8, Fas and PARP) and cell cycle proteins (cyclin D1, P21 and P27) were analyzed by western blot and real time PCR. The results of this study demonstrated that PMMA treatment was able to suppress SMCs proliferation, induce cell apoptosis and inhibit cell cycle arrest when compared to the control group in vitro (P<0.05). Simultaneously, the temperature recorded at the periphery of the PMMA specimen was not high enough to casue thermal injury. Furthermore, molecular markers of apoptosis including Fas, caspase-3 and caspase-9 activated, and Bcl-2/Bax dysregulated in the SMCs with PMMA stimulation. In addition, PMMA treatment showed decreased expression of cyclin D1 that induces cell cycle and increased epxression of inhibitory protein P21, with no significant difference of P27 expression. In summary, the present study confirms that PMMA cement can compromise the vitality and apoptosis of SMCs. This cytotoxic effect may be regulated by the biomarkers Fas, Bcl-2, Bax, caspase-3, caspase-9, cyclin D1 and P21, but not on account of thermal damage.

Modeling and vibration characteristics analysis of a DMF rotor system

Liping Zeng,Jieliang Liu,Zihao Wan,Liquan Song,Xingxing Yuan 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

To analyze the vibration response of a rotor system with circumferential short spring dual mass flywheel (DMF) when the primary flywheel speed changes, the interactions (forces and torques) between the primary flywheel, spring seat, spring, and secondary flywheel are analyzed in detail, and the dynamic analysis model of the DMF rotor system is established considering the influence of clearance and friction between parts in the DMF in this study. The vibration response of the DMF is investigated by numerical method. By analyzing the bifurcation diagram, time history, phase trajectories, Poincaré section, and frequency domain of the relative angular displacement, the variation of vibration form of the system under different excitation frequencies are discussed. Besides, the effects of load, primary flywheel speed amplitude, and spring stiffness on system vibration are also analyzed. Finally, some of the results from the analytical study are verified through the DMF rotor system experiments.

Preparation and Properties of Antistatic Polyethylene Film Coated Polypropylene Non-woven Fabrics

Zongqian Wang,Dengfeng Wang,Yinchun Fang,Jieliang Shen 한국섬유공학회 2018 Fibers and polymers Vol.19 No.5

In this paper, antistatic PE/PP coated non-woven fabrics were prepared by the coating process of the antistatic finished PE films and PP non-woven fabrics using the heat pressing process of the hot melt adhesives. The antistatic finishing of polyethylene (PE) films and polypropylene (PP) non-woven fabrics were processed by one face foam finishing and dippad finishing process, respectively. The antistatic properties of PE/PP coated non-woven fabrics which were influenced by the antistatic finishing processes and the thickness of PE films were investigated. The static charges transmission mechanism of these coated non-woven fabrics was illustrated. The results revealed that the static charges were transferred and dissipated by forming the continuous conductive path and network between the film-adhesive and adhesive-fabric due to the hot melt adhesion and squeezing of the antistatic agents existing inside of of the non-woven fabrics matrix and on the film surface. The antistatic properties of coated non-woven fabrics were improved with the increasing of the antistatic agent concentration on the finishing solution. And the antistatic properties of PE films were greatly influenced by the film thickness, the thinner of PE films the much more obvious improvement of the film surface antistatic properties. The finishing process wouldn’t reduce the peeling strength of the coated non-woven fabrics. The antistatic properties of the PE/PP coated non-woven fabrics possessed high washing durability due to the crosslinking fixation effect of the hot melt adhesives which wouldn’t be weakened after several times washing.

An investigation on the bearing capacity of steel girder-concrete abutment joints

Chen Liang,Yuqing Liu,Changjun Zhao,Bo Lei,Jieliang Wu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.3

To achieve a rational detail of the girder-abutment joints in composite integral bridges, and validate the performance of the joints with perfobond connectors, this paper proposes two innovative types of I-shaped steel girder-concrete abutment joints with perfobond connectors intended for the most of bearing capacity and the convenience of concrete pouring. The major difference between the two joints is the presence of the top flange inside the abutments. Two scaled models were investigated with tests and finite element method, and the damage mechanism was revealed. Results show that the joints meet design requirements no matter the top flange exists or not. Compared to the joint without top flange, the initial stiffness of the one with top flange is higher by 7%, and the strength is higher by 50%. The moment decreases linearly in both types of the joints. At design loads, perfobond connectors take about 70% and 50% of the external moment with and without top flange respectively, while at ultimate loads, perfobond connectors take 53% and 26% of the external moment respectively. The ultimate strengths of the reduced sections are suggested to be taken as the bending strengths of the joints.

BMB Reports : Dickkopf-1 is involved in BMP9-induced osteoblast differentiation of C3H10T1/2 mesenchymal stem cells

( Liangbo Lin ),( Quanhe Qiu ),( Nian Zhou ),( Wen Dong ),( Jieliang Shen ),( Wei Jiang ),( Ji Fang ),( Jie Hao ),( Zhenming Hu ) 생화학분자생물학회(구 한국생화학분자생물학회) 2016 BMB Reports Vol.49 No.3

Bone morphogenetic protein 9 (BMP9) is a potent inducer of osteogenic differentiation of mesenchymal stem cells. The Wnt antagonist Dickkopf-1 (Dkk1) is involved in skeletal development and bone remodeling. Here, we investigated the role of Dkk1 in BMP9-induced osteogenic differentiation of MSCs. We found that overexpression of BMP9 induced Dkk1 expression in a dose-dependent manner, which was reduced by the P38 inhibitor SB203580 but not the ERK inhibitor PD98059. Moreover, Dkk1 dramatically decreased not only BMP9-induced alkaline phosphatase (ALP) activity but also the expression of osteocalcin (OCN) and osteopontin (OPN) and matrix mineralization of C3H10T1/2 cells. Furthermore, exogenous Dkk1 expression inhibited Wnt/β-catenin signaling induced by BMP9. Our findings indicate that Dkk1 negatively regulates BMP9-induced osteogenic differentiation through inhibition of the Wnt/β-catenin pathway and it could be used to optimize the therapeutic use of BMP9 and for bone tissue engineering. [BMB Reports 2016; 49(3): 179-184]