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내열변형 저감을 위한 A-Pillar Trim의 마운트 위치 최적설계
전지환(Jihwan Chun),이정환(Junghwan Lee),김종만(Jongman Kim),류승수(Seungsoo Ryu),김해룡(Haeryong Kim),김헌수(Hunsoo Kim),서명원(Myungwon Suh) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Interior parts composed of plastic usually deform under the various temperature conditions. It is necessary to obtain the material properties for thermal deformation analysis under the heat cycle test. Specially, creep data of plastic material was introduced to study the time-dependent deformation behavior of the pillar trim in heat cycle test. The time-hardening version of the power-law creep model was applied to account for the permanent deformation after heat cycle test, verified through the comparison of test result with FEA result for simple model. In this study, a methodology was developed for the optimum design of the A-pillar trim with mount position. The analyzed results were used to approximate a function which was constructed using response surface method. Design procedures were repeated to minimize the thermal deformation at the areas of interest.
Screening of High-producing Strains of D-ribose Using FLIP<SUB>Rbs</SUB>-F16A Biosensor
SeungJoo KIM,Jihwan CHUN,Kyeong-Won KIM,Wonbeom PARK,Jeong-Hyeon YOON,Yong-Cheol PARK,Dae-Hyuk KWEON 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
D-Ribose is a five-carbon monosaccharide. D-Ribose made from D-glucose through the pentose phosphate pathway (PPP), It is an expensive sugar that is a synthetic material for riboflavin, ATP, and analogues of Nucleotides used in antiviral drugs. To increase ribose productivity using Bacillus subtilis, random mutation was performed using 2-Aminopurine. The FLIPRbs-F16A biosensor can measure the concentration of D-ribose by Fluorescence Resonance Energy Transfer (FRET) phenomenon, which appears by CFP on the N-terminal of the ribose binding protein and YFP on the C-terminal. D-Ribose concentrations were analyzed rapidly using the FLIPRbs-F16A biosensor on 60 samples cultured in 96-well plates. 17 strains with a high level of D-ribose production were selected, and strains that produced D-ribose of up to 18.2 g/L in the flask fermentation for 72 hours were found, and the control strain produced ribose of 12.5 g/L in the same culture time. However, there was a colony-by-colony variation in which the productivity of ribose was different for each colony. We need to stabilize the selected mutant strain and proceed with RNA sequencing.
In vivo tracking of human mesenchymal stem cells in experimental stroke.
Kim, Daehong,Chun, Byoung-Gi,Kim, Yeon-Kyung,Lee, Yong Hyun,Park, Cheong-Soo,Jeon, Iksoo,Cheong, Chaejoon,Hwang, Tae-Sun,Chung, Hyungmin,Gwag, Byoung Joo,Hong, Kwan Soo,Song, Jihwan Pergamon Press ; Elsevier Science Ltd ; Elsevier S 2007 CELL TRANSPLANTATION Vol.16 No.10
<P>To understand the fates of human mesenchymal stem cells (hMSCs) following transplantation into a rodent model of middle cerebral artery occlusion (MCAo), magnetic resonance imaging (MRI) techniques were employed, hMSCs were labeled with ferumoxides (Feridex)--protamine sulfate complexes, which were visualized and examined by MRI up to 10 weeks following transplantation. Migration of the transplanted cells to the infarcted area was further confirmed by histological methods. We found that the hMSCs transplanted in MCAo models possess the capacity to migrate to the infarcted area extensively in both ipsilateral and contralateral injections, exhibiting a pathotropism. We also analyzed the detailed migration patterns of transplanted hMSCs. We speculate that the extensive migratory ability of hMSCs may represent a therapeutic potential for developing efficient cell transplantation strategies in stroke.</P>
Producing Full-length Botulinum Neurotoxin (BoNT) Using Protein Conjugation
Minju KIM,Jihwan CHUN,Wonbeom PARK,SeungJoo KIM,Yong Hwan LEE,Nayoon CHOI,Dae-Hyuk KWEON 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Botulinum neurotoxin is the most lethal biological toxin in nature. Regarding its mechanism of action, BoNT has been greatly favored not only for cosmetic purposes, but also for disease treatment. Conventionally, production of BoNT relied on the tedious cultivation of C. botulinum, which yielded BoNT complex containing NAPs (nontoxic neurotoxin-associated proteins). However, the existence of NAPs is detrimental since 1) it greatly increases the molecular weight of the final product (about 900 kDa), and 2) it may reduce the efficacy of BoNT by facilitating resistance development. To resolve such issues, we designed a novel approach to produce BoNT by expressing separated fragments of BoNT (LC-HN and HC domains) followed by protein conjugation. Each domain was fused with conjugative protein fragments and the conjugation efficiency under various conditions including molar ratio, temperature, and time. As a result, we confirmed that the maximal reaction efficiency is achieved when equivalent amount of protein fragments were combined and incubated at 37℃ for 10 min. Moreover, specific sequences of LC-HN were almost completely cleaved by thrombin treatment, confirming the formation of a disulfide bond between the separated LC and HN domains. In this study, we suggest that BoNT can be produced more safely and efficiently through a novel approach employing protein conjugation and specific cleavage.
Auxiliary Role of Oct-1 for the Soluble Expression of Recombinant Protein in Escherichia coli
SeungJoo KIM,Jihwan CHUN,Wonbeom PARK,NaYeon KIM,MinJu KIM,Yong Hwan LEE,Dae-Hyuk KWEON 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
E. coli has been favored for the expression of various heterologous proteins due to its biological properties including fast growth, high cultivation density, and ease of genetic manipulation. However, hydrophobic nature of some proteins makes it extremely difficult to express and acquire the desired products in a soluble and active form. For example, the presence of transmembrane domain and the lack of glycosidic moieties greatly hampered the expression and purification of influenza hemagglutinin (HA), the main target of influenza vaccine, in E. coli. In this study, we employed Oct-1 DNA binding domain as a fusion partner to express and acquire full-length HA in E. coli system. It has been reported that Oct-1 can form plasmid-protein complexes in E. coli cytoplasm, thereby facilitating the soluble expression of recombinant proteins. In the current study, we confirmed that the expression level of Oct-1-HA was significantly increased compared to that of native HA, and the purified Oct-1-HA retained its activity as a consequence of improved solubility. Regarding the data, we suggest that Oct-1 can effectively contribute to the soluble production of heterologous proteins.
Sun-Hong Min,Hoe-Chun Jung,Gun-Sik Park,Jihwan Ahn,Sang Heun Lee,Young Joong Yoon,Junyeon Kim,Jun-Ho Choi,Joonho So IEEE 2010 IEEE transactions on plasma science Vol.38 No.6
<P>Mode conversion of high-power electromagnetic microwave (HPEM) was successfully accomplished using a coaxial-beam rotating antenna (COBRA) in an X-band relativistic backward-wave oscillator (RBWO). The mode conversion from the TM<SUB>01</SUB> mode to the circularly polarized TE<SUB>11</SUB>-likeness mode was identified by both cold test and hot test. To observe whether mode conversion is effective or not, the radiation pattern of TE<SUB>11</SUB>-likeness mode by COBRA lens was compared with the case of the radiation pattern of TM<SUB>01</SUB> mode using simple horn antenna. Their radiation patterns could be described by fluorescent lamps. The experimental results of radiation pattern measurements are shown to be in a reasonable agreement with the simulated one. The maximum value of RF output power appeared at the center of COBRA lens from the experimental results.</P>