PRB 지진격리장치의 성능 검증을 위한 해석 및 실험적 연구

김성조,김세윤,지용수,김봉식,한동석,Kim, Sung-Jo,Kim, Se-Yun,Ji, Yongsoo,Kim, Bongsik,Han, Tong-Seok 한국전산구조공학회 2020 한국전산구조공학회논문집 Vol.33 No.5

본 논문에서는 모듈화(Module)된 부품을 활용한 탄성받침 성능개선기법에 대하여 소개하였다. 각각의 모듈화된 장치들이 지진 강도 및 이동 변위에 따른 단계별 거동을 함으로써 받침의 성능을 개선하게 된다. 모듈화된 장치들은 초기전단저항 블럭, 완충장치, 변위수용가이드, 낙교방지블럭이 있으며, 탄성받침에 추가적으로 적용되었다. 이 장치는 지진의 규모에 따라 4단계로 거동하며, 1차로 설계변위를 수용하고, 2차, 3차에서는 대규모 지진을 수용하며, 4차로는 대규모의 지진에 대해서 낙교방지가 가능하도록 설계되어 탄성받침의 용량 제한을 증가시킨다. 본 논문에서는, 개발기술인 PRB 지진격리장치를 유한요소해석을 통해 해석하여 격리장치의 이론적인 거동이 구현되는지와, 대규모 지진에 해당하는 하중을 견딜 수 있는지 확인하였다. 그리고 이를 바탕으로 실험을 통해 성능평가를 진행하여 두 결과의 비교 분석을 통해 PRB 지진격리장치가 탄성받침의 성능을 개선할 수 있는지 검증하였다. This study introduces a technique for improving the elastomeric-isolator performance using modular devices. The modular devices are shear resistance block, polymer spring, displacement acceptance guide, and anti-falling block. They are installed on the elastomeric isolator as a supplementary device. Each modularized device improves the isolator performance by performing step-by-step actions according to the seismic intensity and displacement. The PRB isolation device works in four stages, depending on the seismic magnitude, to satisfy the target performance. It is designed to accommodate design displacement in the first stage and large magnitude of earthquakes in the second and third stages. This design prevents superstructures from falling in the fourth stage due to large-magnitude earthquakes by increasing the capacity limit of the elastomeric isolator. In this study, the PRB isolation device is analyzed using finite element analysis to verify that the PRB isolation device works as intended and it can withstand loads corresponding to large-magnitude earthquakes. The performance of the PRB isolation device is validated by the analysis, which is further corroborated by actual experiments.

Porphyromonas gingivalis에서의 Hemin 결합 단백질 유전자의 특성 연구

김성조,Kim, Sung-Jo 대한치주과학회 1999 Journal of Periodontal & Implant Science Vol.29 No.3

Porphyromonas gingivalis, a Gram negative, anaerobic, asaccharolytic rod, is one of the most frequently implicated pathogens in human periodontal disease and has a requirement for hemin for growth. A 30 kDa (heated 24 kDa) hemin-binding protein whose expression is both hemin and iron regulated has recently been purified and characterized in this oral pathogen. This study has identified a hemin-binding P. gingivalis protein by expression of a P. gingivalis genomic library in Escherichia coli, a bacterium which does not require or transport exogenous hemin. A library of genomic DNA fragments from P. gingivalis was constructed in plasmid pUC18, transformed into Escherichia coli strain $DH5{\alpha}$ , and screened for recombinant clones with hemin-binding activity by plating onto hemin-containing agar. Of approximately 10,000 recombinant E. coli colonies screened on LB-amp-hemin agar, 10 exhibited a clearly pigmented phenotype. Each clone contained various insert DNA. The Hind III fragment transferred to the T7 RNA polymerase/promoter expression vector system produced a sligltly smaller (21 kDa) protein, a precursor form, immunoreactive to the antibody against the 24 kDa protein, suggesting that the cloned DNA fragment probably carried an entire gene for the 24 kDa hemin-binding protein.

Porphyromonas gingivalis, Prevotella intermedia, 그리고 Prevotella nigrescens에서의 hemin 결합 단백질에 대한 연구

김성조,Kim, Sung-Jo 대한치주과학회 2006 Journal of Periodontal & Implant Science Vol.36 No.1

The results of this study confirm that the availability of hemin influences the expression of selected membrane proteins of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens. A 30 kDa (heated 24 kDa) hemin-binding protein whose expression is hemin regulated was identified and purified in P. gingivalis. A strong hemin-binding function was found by LDS-PAGE and TMBZ staining when P. gingivalis cells were grown under hemin-limited conditions. A 50 kDa cell envelope associated protein, whose expression is hemin regulated, is considered to be a putative hemin binding protein from P. intermedia and P. nigrescens, respectively. N-terminal amino acid sequence analysis of CNBr-digested 24 kDa hemin binding protein from P. gingivalis revealed that this protein belongs to a new, so far undescribed hemin-binding class of proteins. N-terminal amino acid sequence of a 50 kDa putative hemin binding protein from P. intermedia was identical with Enolase from Streptococcus intermedia. Work is in progress to further characterize the molecular structure of these proteins.

Porphyromonas gingivalis의 각종 표면성분이 싸이토카인 형성에 미치는 영향

김성조,Kim, Sung-Jo 대한치주과학회 2005 Journal of Periodontal & Implant Science Vol.35 No.3

This study was carried out to examine the potency of the three surface compo- nents from Porphyromonas gingivalis to stimulate the murine macrophage cell line RAW264.7 to synthesize the pro-inflammatory cytokine tumor necrosis factor alpha($TNF-{\alpha}$) and nitric oxide (NO). Lipopolysaccharide(LPS). lipid A-associated proteins(LAP) and saline-extractable surface -associated material(SAM) were isolated from P. gingivalis 381. $TNF-{\alpha}$ release into culture supernatants was determined by two-site ELISA. NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Western blot analysis of iNOS and analysis of reverse transcription(RT)-PCR products were carried out. The surface components extracted from this bacterium were almost equally potent in stimulating release of $TNF-{\alpha}$ and NO by RAW264.7 cells. $TNF-{\alpha}$ that was being measured immunologically was due to activation of $TNF-{\alpha}$ gene transcription. The present study clearly shows that P. gingivalis surface components fully induced iNOS expression in RAW264.7 cells in the absence of other stimuli. The ability of P. gingivalis surface components to promote the production of $TNF-{\alpha}$ and NO may be important in the pathogenesis of inflammatory periodontal disease.

Prevotella intermedia 및 Prevotella nigrescens의 지질다당질이 대식 세포에서의 Interleukin-8 생성에 미치는 영향

김성조,Kim, Sung-Jo 대한치주과학회 2009 Journal of Periodontal & Implant Science Vol.39 No.2

Purpose: Interleukin-8 (IL-8) is an important mediator of immune and inflammatory reactions and is produced by a variety of different cell types. This study was undertaken to investigate the effects of lipopolysaccharides (LPSs) from Prevotella intermedia and Prevotella nigrescens, the major causes of inflammatory periodontal disease, on the production of IL-8 and the expression of IL-8 mRNA in differentiated THP-1 cells, a human monocytic cell line. Methods: LPSs from P. intermedia ATCC 25611 and P. nigrescens ATCC 33563 were prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. Results: We found that LPS preparations from P. intermedia and P. nigrescens can induce IL-8 mRNA expression and stimulate the release of IL-8 in differentiated THP-1 cells without additional stimuli. Conclusions: There are no previous reports of the ability of P. intermedia and P. nigrescens LPS to stimulate the release of IL-8, and the present study clearly shows, for the first time, that LPSs from P. intermedia and P. nigrescens fully induced IL-8 mRNA expression and IL-8 production in differentiated human monocytic cell line THP-1. The ability of P. intermedia and P. nigrescens LPS to promote the production of IL-8 may be important in the pathogenesis of inflammatory periodontal disease.

PVDF/MgO 마찰재를 이용한 마찰면진장치의 성능 분석

김성조,김지수,한동석,Kim, Sung-Jo,Kim, Ji-Su,Han, Tong-Seok 한국전산구조공학회 2021 한국전산구조공학회논문집 Vol.34 No.4

구조물을 지진 위험으로부터 완화시키기 위한 마찰면진장치의 상용화된 마찰재료 중 폴리테트라플루오로에틸렌(polytetrafluoroethylene, PTFE)은 내화학성과 마찰성능이 우수하다. 그러나 PTFE는 상대적으로 낮은 내마모성을 가지므로 경제적인 마찰재료이며 산화마그네슘(oxide magnesium, MgO)으로 내마모성을 증가시킨 개선된 폴리비닐리덴 플루오라이드(polyvinylidene fluoride, PVDF)를 PTFE의 대안으로 제안하였다. 개발된 PVDF/MgO 마찰재를 이용하여 실험을 통해 마찰성능을 측정하였으며 PTFE의 마찰성능과 비교하였다. 그리고 측정된 마찰계수를 이용하여 마찰면진장치를 설계하였다. 마찰면진장치의 성능은 교량의 비선형 시간이력 해석을 통해 확인하였고, 이를 통해 마찰면진장치의 마찰재료로 PTFE를 대체하여 PVDF/MgO를 사용하는 것에 대한 타당성을 평가하였다. Polytetrafluoroethylene (PTFE) is a commercialized friction material in friction pendulum systems used for earthquake hazard mitigation in structures, and it has excellent chemical resistance and frictional performance. However, PTFE has a relatively low wear resistance for the friction pendulum systems in service. As an alternative to PTFE, a cost-effective frictional material, polyvinylidene fluoride (PVDF) strengthened by magnesium oxide (MgO), with enhanced wear resistance performance is proposed in this study. The frictional performance of the developed PVDF/MgO was evaluated through experiments and compared with that of PTFE. Accordingly, a friction pendulum system was designed using the measured friction coefficient. The performance of this friction pendulum system was evaluated via nonlinear time history analyses of bridges. Subsequently, the plausibility of using PVDF/MgO as an alternative to PTFE as a friction material for friction pendulum systems was discussed.

Prevotella intermedia의 세균내독소가 치은섬유아세포와 치주인대세포에서의 matrix metalloproteinase 및 tissue inhibitor of metalloproteinase의 발현에 미치는 영향

김성조,최은영,최인순,이주연,최점일,김종관,Kim, Sung-Jo,Choi, Eun-Young,Choi, In-Soon,Lee, Ju-Youn,Choi, Jeom-Il,Kim, Chong-Kwan 대한치주과학회 2005 Journal of Periodontal & Implant Science Vol.35 No.1

Matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes and implicated in the remodeling and degradation of extracellular matrix under both physiological and pathological conditions. Connective tissue degradation in periodontal diseases is thought to be due to excessive MMP activities over their specific inhibitors. The effects of lipopolysaccharide (LPS) from Prevotella intermedia, one of the major putative pathogens of periodontitis, on the expression of mRNA for MMPs and tissue inhibitors of metalloproteinases (TIMPs) in human gingival and periodontal ligament fibroblasts were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of mRNAs encoding MMP-1, -2, -3, -10, and -14 was increased in human gingival fibroblasts treated with p. intermedia LPS, whereas MMP-11 and TIMP-2 mRNA expression was decreased in these cells stimulated with LPS. P. intermedia LPS increased the MMP-1, -2, -10, -11, and -14 mRNA expression and decreased TIMP-1 and -2 mRNA expression in human periodontal ligament fibroblasts. These findings imply that P. intermedia LPS may play an important role in the connective tissue degradation in periodontitis.

Isolation and Characterization of a Putative Heminbinding Protein from Prevotella intermedia

김성조,정해영,Kim, Sung-Jo,Chung, Hae-Young The Korean Academy of Periodontoloy 2000 Journal of Periodontal & Implant Science Vol.30 No.4

본 연구는 hemin이 치주질환 주요 병인균주 중의 하나인 Prevotella intermedia의 성장 및 세포막 단백질의 발현에 미치는 영향을 규명하고, hemin 결합에 관여하는 것으로 추정되는 단백질의 순수분리 및 특성 분석을 위해 수행 되었다. 본 연구의 결과에 의하면, hemin은 P.intermedia의 성장 및 세포막 단백질의 발현에 영향을 미쳐, hemin이 고갈된 조건에서 균주의 성장이 현저히 억제되었으며, 약 50 kDa의 세포막 단백질이 현저히 강화되어 발현되었다. 본 연구에서는 hemin 결합에 관여하는 것으로 추정되는 이 50 kDa의 세포막 단백질을 순수분리하였으며, N'-terminal 아미노산 분석을 수행한 결과 이 단백질은 Streptococcus inter - medius의 Enolase와 아미노산 서열 및 분자량이 일치하였다. 한편, 이 단백질에는 disulfidebond가 존재하지 않았다. 본 연구는 P.intermedia에서의 porphyrin 생리 및 hemin 획득기전을 밝히는데 있어 중요한 의의가 있으리라 사료된다.

Prevotella intermedia와 Prevotella nigrescens의 세균내독소에 대한 연구;화학적 분석 및 면역생물학적 활성 평가

김성조,Kim, Sung-Jo 대한치주과학회 2004 Journal of Periodontal & Implant Science Vol.34 No.2

The purpose of this study was to assess some biological activities of lipopolysaccharides (LPSs) from P. intermedia and P. nigrescens. LPS was prepared by the standard hot phenol-water method. NO production was assayed by measuring the accumulation of nitrite in culture supernatants. $TNF-{\alpha}$ production was determined by enzyme-linked immunosorbent assay. Western blot analysis of iNOS and analysis of reverse transcription (RT)-PCR products were carried out. LPS from P. intermedia demonstrated higher KDO content than those from two stains of P. nigrescens. LPSs from P. intermedia and P. nigrescens were mitogenic for spleen cells of BALB/C mouse. The present study clearly shows that LPSs from P. intermedia and P. nigrescens fully induced iNOS expression and NO production in RAW264.7 cells in the absence of other stimuli. Moreover, LPSs from P. intermedia and P. nigrescens clearly induced $TNF-{\alpha}$ production in RAW264.7 cells. The biological activities of LPS from P. intermedia was found to be comparable to those of P. nigrescens LPS. The ability of LPSs from P. intermedia and P. nigrescens to promote the production of NO and $TNF-{\alpha}$ may be important in the pathogenesis of inflammatory periodontal disease.

치은연하 치석제거 및 치근활택술의 치석제거 효과에 대한 임상적 연구

김성조,Kim, Sung-Jo 대한치주과학회 1998 Journal of Periodontal & Implant Science Vol.28 No.2

This study presents an evaluation of the effectiveness of nonsurgical subgingival scaling and root planing related to initial pocket depth, type of teeth, and individual root surfaces. A total of 110 teeth designated for periodontal surgery in 67 patients with marginal periodontitis were selected and received thorough scaling and root planing with standard rigid Gracey curettes. After a healing period of 4 to 8 weeks, residual calculus was assessed at the time of periodontal surgery following the reflection of mucoperiosteal flap. The results demonstrated a high correlation between the percentage of residual calculus and initial pocket depth. It was further noted that tooth type and involved root surface also influenced the rate of calculus remnant. The results of this study suggest that complete removal of subgingival calculus utilizing conventional instrumentation via closed approach is rare.