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류마티스 관절염의 활막 섬유모세포에서 Hypoxia/reoxygenation에 의한 종양 억제 인자 PTEN 발현의 조절
이학용 ( Hak Yong Lee ),류완희 ( Wan Hee Yoo ) 대한류마티스학회 2004 대한류마티스학회지 Vol.11 No.4
Objective: The lack of phosphatase and tensin homolgue deleted on chromosome ten (PTEN) expression was described in rheumatoid synovial tissues and synovial fibroblasts, but exact cause of that in RA is not well known. Hypoxic conditions are thought to exist in inflamed arthritic synovium and therefore, this study was designed to investigate the effects of hypoxia/reoxygenation on the expression of PTEN in synovial fibroblasts of rheumatoid arthritis. Methods: Synovial fibroblasts were isolated from synovial tissues of patients suffering from RA and hypoxic culture was performed by incubating cells in 5% CO2 incubator held at 3% oxygen by the addition of nitrogen gas for 24 hours. Then synovial fibroblasts were cultured for 10 min under normoxic condition for reoxygenation. To know the expression of PTEN and phosphorylated Akt (p-Akt) in synovial fibroblasts, Western blotting analysis was performed. The expression of PIP3 kinase and PTEN was analyzed by immunocytochemical staining. Results: There were less PTEN expression in rheumatoid synovial fibroblasts than that of healthy controls. Hypoxic/reoxygenation stimuli induced down-regulation of PTEN expression in the rheumatoid synovial fibroblasts. In contrast, the expression of PIP3 and p-Akt was increased after stimulation with hypoxia/reoxygenation. Conclusion: These studies suggest that hypoxia/reoxygenation could cause the reduced expression of PTEN in rheumatoid synovial fibroblasts and thus it might thereby contribute to the invasive behaviour of rheumatoid synovial fibroblasts by maintaining their aggressive phenotype in RA.
철도차량 스마트 운영관리를 위한 RFID 기술현황 및 개발 필요성
이상학,차정훈,서봉진,박찬영,하병용,이은미,김창현,이학용,김재식,김관수,송정훈,박세영,황시원,여진경,Lee, Sang-Hak,Cha, Jung-Hoon,Seo, Bong-Jin,Park, Chan-Young,Ha, Byoung-Yong,Lee, Eun-Mi,Kim, Chang-Hyun,Lee, Hak-Yong,Kim, Jae-Sik,Kim, Kwan-Soo 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.2
철도차량에 RFID 시스템을 도입함으로써 철도 부품관리 등을 포함한 철도차량의 스마트한 운영관리가 가능하도록 하는 것은 경제적, 산업적 뿐 아니라 사회적으로도 많은 필요성이 대두되고 있다. 본 논문에서는 해외의 RFID 연구 및 개발 활용사례를 조사 분석하였다. 철도 뿐 아니라 다양한 산업분야에 RFID 기술이 적용된 사례에 관해서도 조사하였다. 철도분야에서는 주로 차량위치 검지, 차량인식 등에 RFID 시스템이 사용된 경우가 거의 대부분이었고 부품의 단순이력 관리 등에 응용한 사례도 있었다. 본 연구를 통해, 세계적으로 이미 여러 산업분야에서 RFID 기술이 활용되고 있고 철도분야에서도 여러 국가에서 RFID 기술을 활용한 운영이 활성화되어 있으나 이러한 기술 활용은 주로 차량운행과 관련된 분야에 국한되어 있고 철도부품의 유지보수 등의 분야에서는 RFID 기술개발 및 활용이 미흡하다는 것을 알 수 있었다. 따라서 국내의 철도차량의 스마트한 운영관리를 위해서는 RFID 기술을 철도부품의 유지보수 및 이력관리에 적용할 수 있는 시스템이 반드시 필요하다. There are many economical and industrial as well as social demands enabling smart management of railway vehicle including parts management by introducing RFID system in railway vehicle. In this paper, overseas researches and developments which use cases of RFID were investigated and analyzed. In this process, cases of various industries adopting RFID technology as well as cases of railway part were investigated. RFID system is used mainly for railway vehicle position detection and identification of vehicles in the field of railway. Also there are cases of application on traceability management of railway vehicle parts. The system in which RFID technology can be applied to railway parts management and traceability management is necessary for smart management of domestic railway vehicle.
위성 DMB 중계기용 Cavity-Backed슬롯 배열 안테나
정희철,이학용,정병운,강기조,박면주,이병제,Jung Hee-Chul,Lee Hak-Yong,Jung Byungwoon,Kang Gi-Cho,Park Myun-Joo,Lee Byungje 한국전자파학회 2005 한국전자파학회논문지 Vol.16 No.4
This paper presents analysis of a slot array antenna having a low side lobe level and high front-to-back ratio for a repeater system of a satellite DMB(Digital Multimedia Broadcasting) service. Antennas for this repeater system require a high gain and enough isolation to reduce interferences between signals in system. Therefore, it is necessary to suppress a side lobe level and to increase front-to-back ratio. Unlike a structure 134 by lossy microstrip lines, in this work a single cavity-backed slot antenna array using a single waveguide feed is proposed to obtain the reliability for high power handling and high radiation efficiency. The side lobe level and front-to-back ratio are enhanced with tapered array technique and an optimized vertical reflector. The measured side lobe levels in H- and E-plane are under $-33.24\;\cal{dB}$ and $-35.78\;\cal{dB}$, respectively. The front-to-back ratio over $37.84\;\cal{dB}$, and the peak gain of over $17\;\cal{dBi}$ are measured.