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          구조 생물학을 이용한 Antifreeze protein의 최근 연구동향

          이준혁(Jun Hyuck Lee), 이성구(Sung Gu Lee), 김학준(Hak Jun Kim) 한국해양연구원 2011 Ocean and Polar Research Vol.33 No.2

          Antifreeze proteins (AFPs) have ice binding affinity, depress freezing temperature and inhibit ice recystallization which protect cellular membranes in polar organisms. Recent structural studies of antifreeze proteins have significantly expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type Ⅰ-Ⅳ AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type Ⅰ AFP has an amphipathic, single α-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type Ⅰ AFP, Type Ⅱ and Ⅲ AFP are compact globular proteins that contain a flat ice-binding patch on the surface. Type Ⅱ and Type Ⅲ AFP show a remarkable structural similarity with the sugar binding lectin protein and C-terminal domain of sialic acid synthase, respectively. Type IV is assumed to form a four-helix bundle which has sequence similarity with apolipoprotein. The results of our modeling suggest an ice-binding induced structural change of Type IV AFP. Insect AFP has β-helical structure with a regular array of Thr-X-Thr motif. Threonine residues of each Thr-X-Thr motif fit well into the ice crystal lattice and provide a good surface-surface complementarity. This review focuses on the structural characteristics and details of the ice-binding mechanism of antifreeze proteins.

        • KCI등재

          대장균을 이용한 북극 효모 Glaciozyma sp. 유래 재조합 결빙방지단백질 LeIBP의 Pilot-scale 생산

          김은재(Eun Jae Kim), 이준혁(Jun Hyuck Lee), 이성구(Sung Gu Lee), 한세종(Se Jong Han) 한국생물공학회 2017 KSBB Journal Vol.32 No.4

          Antifreeze proteins (AFPs) have a unique feature to bind to ice nuclei, and are referred to ice-binding protein (IBP). The AFP, expressed in the cells of some polar organisms, controls cell damage in subzero temperature environments by inhibiting the ice growth and recrystallization. In this study, recombinant LeIBP (Leucosporidium ice-binding protein) from the arctic yeast Glaciozyma sp. (former known as Leucosporidium sp.) was produced in E. coli using a cold shock induction system. The final cell density and concentration of the purified LeIBP were measured to be 8.2 g/L and 1.1 g/L, respectively. The thermal hysteresis (TH) activity of LeIBP was 0.39±0.02°C at 13.25 mg/mL, which means that the scaleup was successfully performed for the production of recombinant LeIBP in heterologous bacterial expression system.

        • KCI등재

          저온 유도 시스템을 가진 재조합 대장균을 이용한 남극 세균 Flavobacterium frigoris PS1 유래 결빙방지단백질의 Pilot-scale 생산

          김은재(Eun Jae Kim), 이준혁(Jun Hyuck Lee), 이성구(Sung Gu Lee), 한세종(Se Jong Han) 한국생물공학회 2015 KSBB Journal Vol.30 No.6

          Antifreeze proteins (AFP) inhibit growth and recrystallization of ice, and permit organisms to survive in cold environments. The AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris icebinding protein), was produced in E. coli using a cold shock induction system. The culture temperature was shifted from 37°C to 15°C and a 20 L culture scale was used. The final weights of dried cell and FfIBP were estimated to be 126 g and 8.4 g, respectively. The thermal hysteresis (TH) activity (1.53°C) of the produced FfIBP was 3.6-fold higher than that of the LeIBP (Leucosporidium ice-binding protein) produced in Picha. The current study demonstrates that large-scale production of FfIBP was successful and the result could be extended to further application studies using recombinant AFPs.

        • KCI등재

          재조합 Pichia pastoris의 유가식 배양을 통한 남극세균 Flavobacterium frigoris PS1 유래 결빙방지단백질의 생산

          김은재(Eun Jae Kim), 도학원(Hackwon Do), 이준혁(Jun Hyuck Lee), 이성구(Sung Gu Lee), 김학준(Hak Jun Kim), 한세종(Se Jong Han) 한국생물공학회 2014 KSBB Journal Vol.29 No.4

          Antifreeze proteins (AFP) inhibit ice growth to permit the survival of polar organisms in the cold environments. The recombinant AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris icebinding protein), was produced using Pichia pastoris expression system. The optimum fermentation temperature (30℃) and pH (5) for FfIBP production were determined using a fedbatch culture system. The maximal cell density and purified FfIBP were 112 g/L and 70 mg/L, respectively. The thermal hysteresis (TH) activity (0.85) of FfIBP obtained using a glycerol-methanol fed-batch culture system was 2-fold higher than that of the LeIBP (Leucosporidium ice-binding protein). This work allows for large-scale production of FfIBP, which could be extended to further application studies using recombinant AFPs.

        • KCI등재

          고령 환자에서 고관절부 골절의 수술 후 사망률

          고덕환 ( Duk Hwan Kho ), 김기환 ( Ki Hwan Kim ), 신주용 ( Ju Yong Shin ), 이준혁 ( Jun Hyuck Lee ), 김동헌 ( Dong Heon Kim ) 대한골절학회 2006 대한골절학회지 Vol.19 No.2

          목적: 고령 환자에서 고관절부 골절의 수술 후 사망률에 대한 통계와 사망률에 영향을 주는 요인들을 분석하여 고관절부 골절 치료에 도움을 주고자 하였다. 대상 및 방법: 1994년 3월부터 2003년 3월까지 본원에서 고관절부 골절로 수술을 시행한 305명의 환자 중 1년 이상 추시 가능하였던 70세부터 103세까지 248명의 환자를 대상으로 사망률을 조사하였다. 평균 연령은 81.3세였다. 성별로는 여자가 176예였고 남자가 72예였다. 골절 부위는 경부 골절이 99예, 전자간부 골절이 149예였다. 수술은 다발성 핀, 압박고 나사, 엔더 정 등의 금속 내고정술과 양극성 반치환술을 시행하였고, 사망에 영향을 준 요인들을 분석하였다. 결 과: 술 후 1년 사망률은 14.1% (35예)이었다. 사망 시기는 술 후 3개월까지가 57.1% (20예), 4개월에서 6개월까지가 25.7% (9예), 7개월에서 1년까지가 17.1% (6예)로 술 후 3개월 이내에 사망률이 가장 높았다. 술 후 1년 사망률은 기존 질환, ASA (American Society of Anesthesiologists)에 따른 술 전 전신상태 등의 영향을 받았으나 연령이나 성별, 골절 부위, 골다공증 정도, 수술까지의 기간에 따른 사망률의 차이는 없었다. 결론: 70세 이상의 고관절 골절의 사망률에 통계적으로 유의한 영향을 주었던 변수들은 기존 질환과 ASA grade와 양극성 반치환술에서 시멘트의 사용이었다. 향후 다양한 인자들에 대해서 보다 많은 연구가 필요할 것으로 생각된다. Purpose: To evaluate the rate of mortality for the elderly patients after treatment of hip fractures and analyze the associated risk factors which might affect their mortality rate. Materials and Methods: About the clinical records on 305 patients who had undergone the treatment in hip fractures, we evaluated the mortality rate of the total number of 248 patients whose age between 70 and 103 who were followed more than 12 months of period between March 1994 and March 2003. The mean age was 81.3 years. The composition of each female and male were 176 and 72 cases respectively. 99 cases were femoral neck fractures, and 149 cases were femoral intertrochanteric fractures. The operation included bipolar hemiarthroplasty and internal fixation using multiple cannulated screws, compression hip screws and Ender nails. We compared and analyzed the relating factors for the mortality rate. Results: The mean postoperative mortality rate was 14.1% (35 cases). The highest mortality rate showed for the postoperative 3 months which was 57.1% (20 cases), between 4 and 6 months was 25.7% (9 cases), and 17.1% (6 cases) were presented for 7 and 12 months. The postoperative mortality rate within 1 year was affected by underlying diseases, ASA (American society of Anesthesiologists) and cemented bipolar hemiarthroplasty. but, there were no significant difference of the other factors such as the age, gender, osteoporosis and delayed operation. Conclusion: The variable factors which affect the mortality rate of the hip fractures in the elderly patients whose age over 70 were mostly determined by underlying diseases, ASA grade, and cemented bipolar hemiarthroplasty. Further study should be necessary for the factors influencing on the mortality rate.

        • KCI등재

          고령의 불안정성 대퇴 전자간 골절 환자에게 전자부 골절 치료

          고덕환 ( Duk Hwan Kho ), 신주용 ( Ju Yong Shin ), 김기환 ( Ki Hwan Kim ), 이준혁 ( Jun Hyuck Lee ), 김동헌 ( Dong Heon Kim ) 대한골절학회 2007 대한골절학회지 Vol.20 No.2

          목 적: 고령의 불안정성 대퇴 전자간 골절 환자에서 동반된 전자부 골절은 단순 방사선 사진보다 수술 시야에서 분쇄 골절이 더 심한 경우가 많고 골다공증이 심해 고정에 있어서 어려움이 있다. 이에 저자들은 8자 및 원형 강선을 고정하여 분쇄된 전자부 골절을 치료하고 이를 평가하고자 하였다. 대상 및 방법: 저자들은 1998년 3월부터 2004년 3월까지 대퇴 전자간 골절로 대퇴거 대치형 주대를 이용하여 양극성 반치환술을 시행하고, 8자 및 원형 강선을 고정하여 전자부 분쇄 골절을 치료한 70세 이상의 고령 환자 중 24개월 이상 추시 가능하였던 28예를 대상으로 하였다. 평균 연령은 80.4세 (70∼103)였다. 여자가 19예, 남자가 9예였으며, 추시 기간은 평균 58개월 (24∼92)이었다. Modified Harris 고관절 점수, 보행능력, 일상생활의 활동력 등의 임상적 평가와 방사선학적 평가를 시행하였다. 결 과: 평균 골유합 기간은 12주였다. 술 후 modified Harris 고관절 점수는 82.3점이었다. 23예(82%)가 수상 전 보행능력을 회복하였고, 22예 (79%)가 기본 생활 활동능력을 회복하였다. 방사선학적 평가에서 전자부의 불유합은 1예에서 발생되었으나 임상적 의의는 없었다. 결론: 고령의 불안정성 대퇴 전자간 골절 환자에서 8자 및 원형 강선을 이용한 전자부 분쇄 골절의 치료는 고정의 편의성, 골유합 기간, 조기 보행 및 비용 효과적 측면에서 보다 적절한 방법으로 사료된다. Purpose: To evaluate the results after fixation with figure of eight and cerclage wiring for comminuted trochanteric fracture. Because comminution of the fem oral trochanteric fracture in elderly patients is severer in the operating field than x-ray findings, so the fixation is more difficult. Materials and Methods: Between March 1998 and March 2004, the clinical records on twenty-eight patients more than 70 years old who underwent the bipolar hem iarthroplaty using calcar replacement type of femoral stem and followed more than 24 months were reviewed. Figure of eight and cerclage wiring was used for the comminuted trochanteric fracture of the fem oral intertrochanteric fracture. The mean age was 80.4 (70~103) years. 19 cases were female, 9 cases were male. Mean follow-up period was 58 (24~92) months. We evaluated the results by modified Harris hip score, walking ability, activity of daily living, radio logic findings and union of the fracture. Results: The mean duration of bony union was 12 weeks. The mean postoperative modified Harris hip score was 82.3. Preoperative walking ability was recovered in 23 cases (82%). Also basic activity of daily living was recovered in 22 cases (79%). Nonunion of trochanter was found in only one case by radio logic evaluation but clinical correlation was not significant. Conclusion: We consider fixation with figure of eight and cerclage wiring for unstable intertrochanteric fracture of femur in the elderly patientis more appropriate in terms of convenience of fixation, duration of union, early am bulation and cost effectiveness.

        • KCI등재
        • KCI등재

          IoT와 Wearables 기술융합을 위한 특허동향분석

          강지호(Ji Ho Kang), 김종찬(Jong Chan Kim), 이준혁(Jun Hyuck Lee), 박상성(Sang Sung Park), 장동식(Dong Sik Jang) 한국지능시스템학회 2015 한국지능시스템학회논문지 Vol.25 No.3

          본 연구는 협력적특허분류(CPC)를 활용한 `사물인터넷(IoT)`과 웨어러블(wearables)`의 기술융합동향 분석에 관한 것이다. 국내 도입 분야가 점차 확대되고 있는 CPC는 기존의 국제특허분류(IPC)보다 세분화된 분류를 제공해 기술 특성을 더 세밀하고 정확하게 반영할 수 있어 특허 정보 분석 시 활용도를 배가시킬 것으로 기대된다. 아직까지 CPC를 특허정보 분석에 활용한 연구가 드물며, 특허분류코드를 활용해 기술융합현상을 분석한 선행연구들 대부분이 IPC코드를 활용하였다. 본 연구에서는 CPC를 활용하여 wearables IoT 영역의 기술융합동향분석을 실시하였고, 이를 위한 사전분석으로서 각 특허에 할당된 CPC와 IPC를 비교분석하였다. 연관규칙 마이닝 기법을 활용한 CPC 코드분석을 통해 융합이 활발하게 발생하는 기술영역들을 도출하고 시간에 따른 추세변화를 파악하였다. This study aims at analyzing the convergence of Internet-of-Things and wearables technologies using cooperative patent classification(CPC). CPC, introduced to an increasing number of technological fields of Korean patents, is expected to be widely used in Patent Informatics because the classification codes in CPC are more specific than those of IPC, which reflect the characteristics of technologies in detail with accuracy. CPC has seldom been used up to date and most of the previous researches on technological convergence used IPC. As a pre ?analysis step for analyzing the trend of technological convergence of IoT and wearables, CPC and IPC codes assigned to each patent were compared. By applying association rule mining to the analysis of CPC codes we identified the technological fields where convergence frequently takes place and examined the trend of technological convergence over time.

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