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Characteristic evaluation of Al_2O_3/CNTs hybrid materials for micro-electrical discharge machining

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 28-32页

作者： Hyun-Seok TAK Chang-seung HA Ho-Jun LEE Hyung-Woo LEE Young-keun JEONG Myung-Chang KANG National Core Research Center for Hybrid Materials Solution Pusan National University Department of Electrical Engineering Pusan National University

The characteristic evaluation of aluminum oxide （A1203）/carbon nanotubes （CNTs） hybrid composites for micro-electrical discharge machining （EDM） was described. Alumina matrix composites reinforced with CNTs were fabricated by a catalytic chemical vapor deposition method. A1203 composites with different CNT concentrations were synthesized. The electrical characteristic of A1203/CNTs composites was examined. These composites were machined by the EDM process according to the various EDM parameters, and the characteristics of machining were analyzed using field emission scanning electron microscope （FESEM）. The electrical conductivity has a increasing tendency as the CNTs content is increased and has a critical point at 5% A1203 （volume fraction）. In the machining accuracy, many tangles of CNT in A1203/CNTs composites cause violent spark. Thus, it causes the poor dimensional accuracy and circularity. The results show that conductivity of the materials and homogeneous distribution of CNTs in the matrix are important factors for micro-EDM of A1203/CNTs hybrid composites.

关键词： A1203/CNTs hybrid materials micro-electrical discharge machining micro-hole electrical conductivity

A novel therapeutic target for peripheral nerve injury-related diseases: aminoacyl-tRNA synthetases

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Neural Regeneration Research 2015年第10期10卷 1656-1662页

作者： Byung Sun park seung Geun Yeo Junyang Jung Na Young Jeong Department of Anatomy and Neurobiology School of Medicine Kyung Hee University Department of Otolaryngolgy Head and Neck Surgery School of Medicine Kyung Hee University Department of Anatomy and Cell Biology College of Medicine Dong-A University

Aminoacyl-t RNA synthetases（Amino ARSs） are essential enzymes that perform the first step of protein synthesis. Beyond their original roles, Amino ARSs possess non-canonical functions, such as cell cycle regulation and signal transduction. Therefore, Amino ARSs represent a powerful pharmaceutical target if their non-canonical functions can be controlled. Using Amino ARSs-specific primers, we screened m RNA expression in the spinal cord dorsal horn of rats with peripheral nerve injury created by sciatic nerve axotomy. Of 20 Amino ARSs, we found that phenylalanyl-t RNA synthetase beta chain（FARSB）, isoleucyl-t RNA synthetase（IARS） and methionyl-t RNA synthetase（MARS） m RNA expression was increased in spinal dorsal horn neurons on the injured side, but not in glial cells. These findings suggest the possibility that FARSB, IARS and MARS, as a neurotransmitter, may transfer abnormal sensory signals after peripheral nerve damage and become a new target for drug treatment.

关键词： nerve regeneration aminoacyl-t RNA synthetases dorsal horn peripheral nerve injury in situ hybridization neural regeneration

Monascus pilosus-fermented black soybean inhibits lipid accumulation in adipocytes and in high-fat diet-induced obese mice

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Asian Pacific Journal of Tropical Medicine 2015年第4期8卷 276-282页

作者： Young-Sil Lee Bong-keun Choi Hae Jin Lee Dong-Ryung Lee Jinhua Cheng Won-keun Lee seung Hwan Yang Joo-Won Suh Center for Nutraceutical and Pharmaceutical Materials Myongji University Interdisciplinary Program of Biomodulation Myongji University Division of Bioscience and Bioinformatics College of Natural ScienceMyongji University

Objective:To explore the anti-obesity effects and the mechanism of action of Monascus pilosus(***)-fermented black soybean(MFBS)extracts(MFBSE)and MFBS powders(MFBSP)in adipocytes and high-fat diet(HFD)-induced obese mice,***:Black soybean was fermented with ***,and the main constituents in MFBS were analyzed by HPLC *** vitro,MFBSE were examined for anti-adipogenic effects using Oil-Red O *** vivo,mice were fed a normal-fat diet(NFD)control,HFD control or HFD containing 1 g/kg MFBSP for 12 weeks,and then body weight gain and tissues weight ***-time PCR and western blot assay were used to determine the mechanism of anti-adipogenic ***:MFBSE inhibited lipid accumulation in 3T3-L1 adipocytes without exerting cell *** treatment in HFD-fed mice significantly decreased the body weight gain compared with the HFD control *** and MFBSP treatment resulted in significantly lower mRNA levels of adipogenesis-related genes,such as peroxisome proliferator-activated receptorγ(PPARγ),fatty acid-binding protein 4(FABP4),and fatty acid synthase(FAS),in adipocytes and in white adipose tissue(WAT)of HFD-induced obese ***:These results suggest that the anti-obesity effects of MFBS are elicited by regulating the expression of adipogenesis-related genes in adipocytes and WAT of HFDinduced obese mice.

关键词： Monascus pilosus Black soybean Adipocytes High-fat diet-induced obese mice Anti-obesity Adipogenesis-related genes

Roots extracts of Adenophora triphylla *** improve obesity in 3T3-L1 adipocytes and high-fat diet-induced obese mice

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Asian Pacific Journal of Tropical Medicine 2015年第11期8卷 879-886页

作者： Dong-Ryung Lee Young-Sil Lee Bong-keun Choi Hae Jin Lee Sung-Bum park Tack-Man Kim Han Jin Oh seung Hwan Yang Joo-Won Suh NutraPham Tech Center for Nutraceutical and Pharmaceutical Materials Myongji University Interdisciplinary Program of Biomodulation Myongji University DONG IL Pharmtec Department of Family Medicine.VIEVIS NAMUH Hospital

Objective:To investigate the anti-obesity activity and the action mechanism of the roots of Adenophora triphylla *** extract(ATE) in high-fat diet(HFD)-induced obese mice and 3T3-LI ***:The roots of Ademption triphylla were extracted with 70%*** demonstrate the compounds,linoleic acid was analyzed by using gas chromatography:and the anti-obesity effects and possible mechanisms of ATE were examined in 3T3-L1 adipocytes and HFD-induced obese ***:Treatment with ATE inhibited the lipid accumulation without cytotoxicity in 3T3-L1 ***,200 and 400 mg/kg ATE treatment significantly decreased the body weight gain,white adipose tissues(WATs) weight and plasma triglyceride level,while 100 and 200 mg/kg ATE treatment increased the plasma high-density lipoprotein cholesterol level in the HFD-induced obese mice,as compared with the HFD *** with 200 and 400 mg/kg ATE also lowered the size of adipocytes in adipose tissue and reduced the lipid accumulation in *** treatment showed significantly lower expression level of adipogenesis-relatcd proteins,such as peroxisome proliferator-activated receptor y,fatty acid binding protein(aP2),fatty acid synthase in 3T3-L1 adipocytes;and furthermore,decreased peroxisome proliferatoractivated receptor γ,aP2,fatty acid synthase,sterol regulatory element binding protein-1c,and lipoprotein lipase mRNA expression levels in WAT of the HFD-induced obese ***:These results suggested that the ATE has an anti-obesity effect,which may be elicited by regulating the expression of adipogenesis and lipogenesis-related genes and proteins in adipocytes and WAT of the HFD-induced obese mice.

关键词： Roots of Adenophora triphylla var. japonica extrac

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

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Chinese Journal of Chemical Engineering 2017年第3期25卷 278-287页

作者： Eun-Sung Jo Xinghai An Pravin G.Ingole Won-Kil Choi Yeong-Sung park Hyung-keun Lee Korea Institute of Energy Research(KIER) 71-2 Jang-dongYuseong-guDaejeon 205343Republic of Korea Department of Environmental Engineering Daejeon UniversityDaejeonRepublic of Korea Department of Advanced Energy and Technology University of Science and Technology(UST)217 Gajeong-roYuseong-guDaejeon 305-350Republic of Korea

Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.

关键词： Thin-film composite hollow fiber membrane Interfacial polymerization CHMA/TMC CO2/CH4 separation

Fabrication of 3D Printed PCL/PEG Polyblend Scaffold Using Rapid Prototyping System for Bone Tissue Engineering Application

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Journal of Bionic Engineering 2018年第3期15卷 435-442页

作者： Su A park Sang Jin Lee Ji Min Seok Jun Hee Lee Wan Doo Kim Il keun Kwon Department of Nature-Inspired Nanoconvergence Systems Korea Institute of Machinery and Materials 156 Gajeongbuk-ro Yuseong-gu Daejeon 34103 Republic of Korea Department of Dental Materials School of Dentistry Kyung Hee University 26 Kyungheedae-ro Dongdaemun-gu Seou102447 Republic of Korea

Three-dimensional （3D） printing is a novel process used to manufacture bone tissue engineered scaffolds. This process allows for easy control of the architecture at the micro structure. However, the scaffold properties are typically limited in terms of cellular activity at the scaffold surface due to the printed materials properties. In this study, we developed a polycaprolactone （PCL） blended with polyethylene glycol （PEG） 3D printed scaffold using a rapid prototyping system. The manufactured scaffolds were then washed out to form small pores on the surface in order to improve the scaffolds hydrophilicity. We analyzed the resultant material by using Scanning Electron Microscopy （SEM）, water absorption, water contact angle, in vitro WST-1, and the Bradford assay. Additionally, cells incubated on the fabricated scaffolds were visualized by Confocal Laser Scanning Microscopy （CLSM）. The developed scaffolds exhibited small pores on the strand surface which served to increase hydrophilicity as well as improve cellular proliferation and increase total protein content. Our findings suggest that the presence of small pores on the scaffolds can be used as an effective tool for improving implant cellular interaction. This research indicates that these modified scaffolds can be considered useful for bone tissue engineering applications to improve human health.

关键词： polycaprolactone polyethylene glycol polyblend 3D printing porosity bone tissue engineering

Monitoring biofouling based on aerobic respiration in reverse osmosis system

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Journal of Environmental Sciences 2019年第4期31卷 247-256页

作者： Youngjae Yu keun-Young park Jaehyun Jung Wonjung Song Jaehyeok Kim Junhee Ryu Harshad Lade Jihyang Kweon Department of Environmental Engineering Konkuk University Department of Environment and Energy Sejong University Department of Laboratory Medicine Hallym University Medical Center

A monitoring method of biofouling in reverse osmosis(RO) system was proposed based on the fluorescent signal of resorufin, which is reduced by nicotinamide adenine dinucleotide released from viable cells during aerobic respiration. The fluorescent signal of resorufin reduced by planktonic cells and microorganisms of biofilm showed linearity, indicating its feasibility to monitor biofouling in a RO system. For the application of the method to the lab-scale RO system, the injection concentration of resazurin and the injection flow rate were optimized. Biofilm on RO membranes continuously operated in a lab-scale RO system was estimated by resorufin fluorescence under optimized detection condition. As a result,resorufin fluorescence on RO membrane showed a significant increase in which the permeability of RO system decreased by 30.48%. Moreover, it represented the development of biofilm as much as conventional biofilm parameters such as adenosine triphosphate,extracellular polymeric substances, and biofilm thickness. The proposed method could be used as a sensitive and low-cost technology to monitor biofouling without autopsy of membranes.

关键词： On-site monitoring Biofilm Aerobic respiration Resazurin reduction mechanism Resorufin fluorescence

Optimal Design of Bobbinless Rotary Magnetorheological Material Based Brake

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Journal of Iron and Steel Research International 2012年第S1期19卷 495-500页

作者： NGUYEN Quoc-hung CHOI seung-bok SONG Byung-keun Department of Mechanical Engineering Inha UniversityIncheon 402-751Korea Department of Mechanical System Engineering University of IncheonIncheon 406-840Korea

The paper presents a novel configuration in order to improve the compactness and manufacturing cost of magneto-rheological material(or fluid)based brakes(MRB in short).In conventional configurations of MRBs,the coil is normally wound on a nonmagnetic bobbin which is placed on the *** causes difficulties in manufacturing of the brake and the bottle-neck problem of magnetic *** the proposed configuration,the coil is wound directly on the inner cylinder of the *** this case,the inner cylinder of the housing should be designed in a special shape that maximizes the magnetic flux across the MR fluid(MRF)*** proposing of the new configuration of the MRBs,the modeling of the MRBs is performed based on Bingham rheological model of the *** optimal design of the proposed MRBs and conventional MRBs is then performed based on finite element analysis results of magnetic circuit of the MRBs.A comparative work between the optimal parameters of the proposed MRBs and conventional MRBs is conducted and the advanced performance characteristics of the proposed MRBs are investigated.

关键词： magneto-rheological fluid magneto-rheological brake optimal design finite element method

Size-dependent transition of the deformation behavior of Au nanowires

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Nano Research 2015年第3期8卷 941-947页

作者： Na-Young park Ho-Seok Nam PiI-Ryung Cha seung-Cheol Lee School of Advanced Materials Engineering Kookmin University Seou1136-702 R. O. Korea Future Convergence Research Division Korea Institute of Science and Technology (KIST) Seou1136-791 R. O. Korea Indo-Korea Science and Technology Center Korea Institute of Science and Technology (KIST) Seou1136-791 R. O. Korea

Inspired by the controversy over tensile deformation modes of single-crystalline 〈110〉/{111} Au nanowires, we investigated the dependency of the deformation mode on diameters of nanowires using the molecular dynamics technique. A new criterion for assessing the preferred deformation mode-slip or twin propagation--of nanowires as a function of nanowire diameter is presented. The results demonstrate the size-dependent transition, from superplastic deformation mediated by twin propagation to the rupture by localized slips in deformed region as the nanowire diameter decreases. Moreover, the criterion was successfully applied to explain the superplastic deformation of Cu nanowires.

关键词： Au nanowire molecular dynamics size-dependent transition tensile deformationmechanism