천리안 위성 영상 기반 태양자원지도를 활용한 다양한 정의에서의 청천지수 특성 분석

김창기,김현구,강용혁,윤창열 한국태양에너지학회 2019 한국태양에너지학회 논문집 Vol.39 No.3

Clear sky indices were estimated by various ways based on in-situ observation and satellite-derived solar irradiance. In principle, clear sky index defined by clear sky solar irradiance indicates the impacts of cloud on the incoming solar irradiance. However, clear sky index widely used in energy sciences is formulated by extraterrestrial irradiance, which implies the extinction of solar irradiance due to mainly aerosol, water vapor and clouds drops. This study examined the relative difference of clear sky indices and then major characteristics of clear sky irradiance when sky is clear are investigated. Clear sky is defined when clear sky index based on clear sky irradiance is higher than 0.9. In contrast, clear sky index defined by extraterrestrial irradiance is distributed between 0.4 and 0.8. When aerosol optical depth and air mass coefficient are relative larger, solar irradiance is lower due to enhanced extinction, which leads to the lower value of clear sky index defined by extraterrestrial irradiance.

Mecillinam의 임상분리 장내세균 대한 시험관내 항균력

김창기,염종화,이상국,이양순,최준용,김준명,정윤섭,이경원 대한감염학회 2009 Infection and Chemotherapy Vol.41 No.3

Background:Mecillinam, an amidinopenicillin antibiotic, has been used to treat urinary tract infections and bacterial enteritis in many countries. In this study, we evaluated in vitro activity of mecillinam against Enterobacteriaceae isolates from urine, and Salmonella and Shigella isolates from patients with bacterial gastroenteritis. Materials and Methods:A total of 308 clinical strains were collected and were comprised of Escherichia coli (n=109), Klebsiella pneumoniae (n=52), Enterobacter spp. (n=30), Serratia marcescens (n=30) and Proteus spp. (n=29) isolated from a university hospital in Korea in 2007, and of Salmonella spp. (n=28) and Shigella spp. (n=30) isolated from Korean diarrheal patients from 2001 to 2006. Antimicrobial susceptibility was tested by Clinical Laboratory Standard Institute (CLSI) agar dilution method. CLSI breakpoint of mecillinam for E. coli urinary tract isolates was applied to all other isolates. Results:In E. coli, rate of susceptibility to ampicillin was 30%, but 99-100% to amikacin and cefotaxime. Most (96%) of E. coli isolates, including extended-spectrum β-lactamase (ESBL) producers, were susceptible to mecillinam. All ESBL producers, except for one isolate, were inhibited by ≤4 µg/mL of mecillinam. MIC90 of mecillinam for K. pneumoniae and Enterobacter spp. was 8 µg/mL and 1 µg/mL, respectively, and the susceptibility rate was 92% and 97%, respectively. However, MIC90 of mecillinam for S. marcescens isolates was >128 µg/mL and most of them were resistant to mecillinam. All Salmonella isolates and 27 of 30 Shigella isolates were susceptible to mecillinam. Conclusion:Mecillinam was active in vitro against most Enterobacteriaceae, Salmonella, and Shigella isolates except for S. marcescens. Therefore, mecillinam can be a good alternative agent for treating urinary tract infection and bacterial gastroenteritis. Background:Mecillinam, an amidinopenicillin antibiotic, has been used to treat urinary tract infections and bacterial enteritis in many countries. In this study, we evaluated in vitro activity of mecillinam against Enterobacteriaceae isolates from urine, and Salmonella and Shigella isolates from patients with bacterial gastroenteritis. Materials and Methods:A total of 308 clinical strains were collected and were comprised of Escherichia coli (n=109), Klebsiella pneumoniae (n=52), Enterobacter spp. (n=30), Serratia marcescens (n=30) and Proteus spp. (n=29) isolated from a university hospital in Korea in 2007, and of Salmonella spp. (n=28) and Shigella spp. (n=30) isolated from Korean diarrheal patients from 2001 to 2006. Antimicrobial susceptibility was tested by Clinical Laboratory Standard Institute (CLSI) agar dilution method. CLSI breakpoint of mecillinam for E. coli urinary tract isolates was applied to all other isolates. Results:In E. coli, rate of susceptibility to ampicillin was 30%, but 99-100% to amikacin and cefotaxime. Most (96%) of E. coli isolates, including extended-spectrum β-lactamase (ESBL) producers, were susceptible to mecillinam. All ESBL producers, except for one isolate, were inhibited by ≤4 µg/mL of mecillinam. MIC90 of mecillinam for K. pneumoniae and Enterobacter spp. was 8 µg/mL and 1 µg/mL, respectively, and the susceptibility rate was 92% and 97%, respectively. However, MIC90 of mecillinam for S. marcescens isolates was >128 µg/mL and most of them were resistant to mecillinam. All Salmonella isolates and 27 of 30 Shigella isolates were susceptible to mecillinam. Conclusion:Mecillinam was active in vitro against most Enterobacteriaceae, Salmonella, and Shigella isolates except for S. marcescens. Therefore, mecillinam can be a good alternative agent for treating urinary tract infection and bacterial gastroenteritis.

제대혈 유래 CD34 양성세포로부터 적혈구 분화유도와 Microarray를 이용한유전자 프로파일 분석

김창기,이지혁,박광일,김현숙,유철주,라선영,김현옥 대한진단검사의학회 2005 Annals of Laboratory Medicine Vol.25 No.6

Background : In this study, we attempted to generate RBCs from CD34+ cells in cord blood using a 3-step culture protocol and also evaluated a change in immunophenotypic characteristics and expression profile according to erythropoietin (EPO) concentrations and culture duration. Methods : Using mini-MACS columns, CD34+ cells were isolated from cord blood. The culture procedure comprised three steps. For each step, cells were cultured sequentially for 7 days in a serum free liquid medium with a specific combination of growth factors for 21 days. [1st step: Flt3-ligand (Flt3-L), thrombopoietin and stem cell factor (SCF); 2nd step: IGF-1, SCF and EPO; and 3rd step: IGF-1 and EPO] To evaluate the effect of EPO on proliferation and differentiation, cells were cultured with different EPO concentrations (0, 3, 10 & 20 U/mL). Cell count and morphology were monitored during the culture. For phenotyping, antibodies to CD34, CD38, CD45 and glycophorin A (GPA) were used. The expression profile of cultured cells was analyzed by 17,000-gene microarray analysis. Results : As EPO concentration increased, cell expansion was also increased, showing a maximum expansion at 20 U/mL. The cell population showed a gradual decrease in expression of CD34 and CD45, whereas the expression of GPA was not prominent in any conditions. However, we observed increased expression in some genes associated with erythropoiesis (e.g. glycophorin A, rhesus blood group CcEe antigens). Conclusions : This study shows that erythropoietin enhances the proliferation of hematopoietic progenitor cells. Our culture system did not achieve pure production of RBCs, but induced expression changes that indicated erythroid differentiation 배경 : 본 연구에서는 제대혈의 CD34 양성세포를 분리하여erythropoietin (EPO) 등의 자극을 통하여 적혈구로 분화를 시도하였다. 또한 EPO 농도와 첨가시기가 배양에 미치는 영향을 규명하기 위하여 유세포검사를 통해 면역표현형을, microarray를 이용하여 유전자 발현의 변화를 알아보고자 하였다.방법 : 제대혈의 CD34 양성세포를 다양한 성장인자를 첨가한배지에서 3주간 배양하였고, EPO의 농도와 첨가시기를 달리하여배양하였다. 배양에 따른 세포의 형태와 면역표현형 그리고 유전자 발현의 변화를 분석하였다.결과 : 배양세포는 모든 조건에서 14일에 가장 높은 증식을 보였으며 EPO의 농도가 높을수록 처음부터 첨가할수록 좋은 증식을 보였다. CD34와 CD45는 초기에 90% 이상 높게 표현하였고배양이 진행되면서 그 표현이 감소하였다. 그러나 적혈구에 특이적인 항원인 glycophorin A (GPA)의 표현이 두드러지 않았다. Microarray 분석 결과 배양이 진행되면서 적혈구생성과 관련이 깊은 유전자들의 발현이 증가하였다. 결론 : 배양이 진행되면서 적혈구 생성과 관련된 여러 유전자의 발현 증가를 관찰할 수 있었으나, 이런 변화가 배양 세포의 형태와 면역 표현형의 변화로 이어지지는 못하였다. 따라서 생체내의 조건과 좀 더 유사한 배양 조건을 규명하는 연구가 필요할 것으로 생각된다.

위해성평가와 관리를 고려한 유전자변형작물 개발의 필요성

김창기,정순천,윤원기,박기웅,최경화,김환묵 한국식물생명공학회 2009 식물생명공학회지 Vol.36 No.4

Over the last five years, we have conducted research on risk assessment of domestically developed genetically modified (GM) crops and found a number of factors which could delay risk assessment process. In this review, we described such cases and discussed the problem of transgene cassette integration, the lack of information on vectors, the poor quality control in seed production and absence of bioinformatic analysis on amino acid sequence homology before GM crop development. To solve these problems, we have suggested the introduction of the screening system of elite event before risk assessment process and quality control strategies for GM seed production. In addition, we suggested that the developers of GM crops should understand the importance of risk assessment and management for the commercialization of those crops and consider the biological and ecological characteristics of host plants. Consistent communications may need to be established between GM crop developers, risk assessors and risk managers at the initial stages of GM crop development to reduce trial-and-errors. 지난 5년간 국내에서 개발된 GM 작물의 위해성평가를 수행하는 과정에서 위해성평가를 지연시키는 여러 가지 장애요인들이 발견되었다. 본 총설에서는 이러한 장애요 인들을 사례를 들어 설명하고, 특히 도입유전자 cassette 삽입과 관련된 문제점, 운반체 정보의 부재, 종자 생산 시 품질 관리의 문제, GM 작물 개발에 앞서 알레르기 유 발성 평가를 위한 bioinformatics 분석의 부재가 가져온 문 제점들을 논의하였다. 이러한 문제점들을 해결하기 위하 여 위해성평가 이전에 우량 이벤트의 스크리닝 시스템의 도입과 GM 종자 생산의 품질 관리 전략 수립을 제안하 였다. 또한 개발자들이 GM 작물의 상업화를 위해 위해 성 평가 및 관리의 중요성을 이해하고, GM 작물 개발 시 숙주 식물의 생물학적, 생태학적 특성을 고려할 것을 제 안하였다. GM 작물 개발의 시행착오를 줄이기 위해 작 물 개발 초기부터 개발자, 위해성 평가자 및 위해성 관리 자 사이의 지속적인 교류가 필요하다고 판단된다.

지역복지증진을 위한 사회복지협의회와 지역사회보장협의체 상생협력방안 토론문

김창기 한국지역사회복지학회 2021 한국지역사회복지학회 학술대회 Vol.2021 No.11

다제내성결핵균에서 주사제 내성의 분자생물학적 검출

김창기,안병철,이준환,이병수,최명준,김희진 대한결핵 및 호흡기학회 2011 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.112 No.-

Pricing the Options in Housing Contracts and Risk Management

김창기,신동훈,김명현,정승영 국토연구원 2015 국토연구 Vol.85 No.-

The recent global financial crisis has hampered economic activities in many ways; however, the impact on the real estate market has been particularly huge. In Korea, falling real estate prices has meant many construction companies going bankrupt because of the vast number of unsold apartments. To alleviate this problem, construction companies have begun to provide potential apartment buyers with free options such as the withdrawal guarantee option, principal guarantee option, premium guarantee option, and buy-back option. In this study, we attempt to analyze the real value and the market risk of these options which has no market value yet. To price the options, we used GARCH option pricing model and Esscher transform. As the result, the price of the withdrawal guarantee option was significantly higher than the other options, and this fact implies that this option may be attractive to the investor in terms of marketing, while the construction firms as issuer may pay the costs. In addition, we applied the DD(Default to Distance) of two companies and VaR of the options in order to manage the risk caused by the options. As the result, according to the analysis of the DD, the issue of the options seems to be helpful to the company immediately. According to the VaR analysis, the principal guarantee option is the most risky option among the options by falling the value of the asset and the value of the option in depressing markets.

인천 국제공항 안개에 대한 기상학적 특성분석

김창기,염성수 한국기상학회 2009 한국기상학회 학술대회 논문집 Vol.2009 No.10

TB 클릭닉 - 결핵의 진단 -새로운 결핵진료지침을 중심으로

김창기,Kim, Chang-Gi 대한결핵협회 2011 보건세계 Vol.58 No.4

국내 임상결핵검사실 생물안전 실태조사

김창기,이혁민,용동은,김영아 대한진단검사의학회 2017 Laboratory Medicine Online Vol.7 No.4

Background: Workers in the microbiology laboratories are continuously exposed to the risk of laboratory-associated infections. Tuberculosis (TB) is a frequent laboratory-acquired infection owing to production of cough-generated aerosols with ease and high infectivity of Mycobacterium tuberculosis. This study aims to investigate the current situation of biosafety in Korean TB laboratories. Methods: We conducted a nationwide survey of laboratories in hospitals conducting TB tests using questionnaires about their facility and management standards. Results: We analyzed data from 52 hospitals nationwide that have a capacity of 100–2,000 beds, of which only two laboratories conduct high risk drug-susceptibility testing on cultured isolates among other test items, whereas six laboratories perform only direct sputum-smear microscopy. The remaining laboratories performed moderate-risk activities/tests, like sample processing for culture. In the majority of these laboratories, there are laboratory medicine specialists who are fully in charge of health checkup programs for laboratorians. The facility and management standards vary widely according to the size of the hospital and risk of TB tests. Conclusions: Our survey results about the current situation of TB laboratories could be useful as baseline data for preparing biosafety guidelines for all TB laboratories in Korea. 배경: 미생물 검사실의 검사자는 검사실 연관 감염의 위험에 노출되어 있다. 결핵은 검사 중 발생한 에어로졸에 의해 쉽게 감염될 수 있는 질환이다. 방법: 본 연구에서는 국내 결핵검사실의 생물안전 현황을 파악하기 위해 전국단위 설문조사를 실시하였다. 설문문항은 시설기준과 운영에 대한 기존 연구를 활용하였고 진단검사의학재단 우수검사실 신임인증평가에 참여하는 기관 중 결핵검사를 시행하는 기관을 대상으로 하였다. 결과: 전체 52개 임상검사실에서 회신을 주었고 약제감수성검사를 시행하는 2기관을 제외하고는 모두 병원 검사실이었으며 병상수는 100에서 2,000개로 다양하였다. 6개 검사실은 도말검사만을 시행하고 있었다. 대부분의 검사실에서 진단검사 전문의가 검사실과 검사자의 검진프로그램에 대해 책임을 지고 있었다. 결핵검사실의 시설과 운영은 병원의 크기와 시행하는 검사의 위험도에 따라 다양하였다. 결론: 본 설문결과는 국내 결핵검사실 생물안전지침을 마련하기 위한 기초자료로 유용할 것으로 판단된다.