진통소염제에 의한 위 십이지장 궤양에 합병된 위 출구 폐쇄 1예

최창환,변성환,장수희,백소야,Choi, Chang Hwan,Byun, Sung Hwan,Chang, Soo Hee,Paik, So Ya 대한소아소화기영양학회 2005 Pediatric gastroenterology, hepatology & nutrition Vol.8 No.2

저자들은 11개월 영아의 고열을 조절하기 위해 진통소염제 근주와 경구 해열제 병용투여 후 발생한 다발성 식도 위 십이지장 궤양 치료 과정 중 조기에 위 출구 폐쇄가 합병된 1예를 경험하였기에 보고하는 바이다. Peptic ulcer disease complicated with gastric outlet obstruction is rare in children. Even though NSAIDs have been reported to cause various adverse events, they are still regarded as safe and, therefore, widely utilized in children. In the past, pediatric patients who were at risk of seizure due to high fever, were treated with dipyrone (Metamizole sodium) injection which inhibits cyclooxygenase-1 and inhibit prostaglandin, to weaken the gastro-duodenal defensive mechanism. A case of an infant with multiple esophagogatroduodenal ulcers and bleeding caused by NSAID complicated with gastric outlet obstruction is reported in this paper.

과민성 장증후군과 면역 활성화

최창환 ( Chang Hwan Choi ),설혜령 ( Hye Ryoung Sul ) 대한장연구학회 2008 Intestinal Research Vol.6 No.2

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder characterized by chronic abdominal pain and bowel habit change. Its specific pathophysiologic mechanism underlying IBS is not known; however, it is generally accepted that IBS symptoms represent dysregulation at multiple levels of the brain-gut axis. IBS symptoms are manifested by abnormal motor reactivity to various stimuli, and low sensation and pain thresholds. Recently, a variety of new findings have been reported which suggests low-grade inflammation or immune activation is present in IBS patients, including post-infectious IBS. The immune activation can generate various symptoms such as abdominal pain, bloating, and diarrhea that may result from motor dysfunction and visceral hypersensitivity. Anti-inflammatory therapy with either antibiotics or probiotics seems to be effective in reducing the symptoms of IBS. While this pathophysiologic approach to the management of IBS is in its infancy, it is evident that the immune activation deserves further attention in IBS. (Intest Res 2008;6:95-102)

지가의 공간분포 분석을 통한 부산시 도시공간구조해석에 관한 연구

최창환(Choi Chang Hwan),이동본(Lee Dong Bon) 한국부동산학회 2005 不動産學報 Vol.25 No.-

1. CONTENTS (1) RESEARCH OBJECTIVES This study investigates the urban spatial structure which analyzes land distribution into its price in Busan. The land is limited resources, so the price and property of land are changed. It affects the urban spatial structure. Therefore it is important that the urban spatial structure was explained by using the price of land. (2) RESEARCH METHOD cluster analysis (3) RESEARCH RESULTS As result we realized that they have no relations between density of population and the price of land, but between the price of land and the distance from downtown have relations. The relations explained that farther place from downtown is lower price of land than a location which is near to downtown. 2. RESULTS The study reaches the two conclusion : first, the spatial structure of Busan was divided into two parts of inner functional space, a part of outer functional space and 7 parts of outer area. The second conclusion of the study is that the price of outer land is more expansive than center of city in some cases. 3. KEY WORDS the piece of land, urban spatial structure, Cluster Analysis, a economic zone

수복재료와 임플랜트 종류에 따른 임플랜트 및 지지조직의 응력분포

최창환,오종석,방몽숙,Choi Chang-Hwan,Oh Jong-Suk,Vang Mong-Sook 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.1

This study was aimed to analyze the stress distribution of implant and supporting tissue in single tooth implant restoration using Branemark $system^{(R)}$(Nobel Biocare, Gothenberg, Sweden) and Bicon system(Bicon Dental Implants, Boston, MA). Two dimensional finite element analysis model was made at mandibular first premolar area As a crown materials porcelain, ceromer, ADA type III gold alloy were used. Tests have been performed at 25Kgf vertical load on central fossa of crown portion and at 10Kgf load with $45^{\circ}$ lateral direction on cusp inclination. The displacement and stresses of implant and supporting structures were analyzed to investigate the influence of the crown material and the type of implant systems by finite element analysis. The results were obtained as follows : 1. The type of crown material influenced the stress distribution of superstructure, but did not influence that of the supporting alveolar bone. 2. The stress distribution of ceromer and type III gold alloy and porcelain is similar. 3. Stress under lateral load was about twice higher than that of vertical load in all occlusal restorative materials. 4. In Bicon system, stress concentration is similar in supporting bone area but CerOne system generated about 1.5times eater stress more in superstructure material. 5. In Branemark models, if severe occlusal overload is loaded in superstvucture. gold screw or abutment will be fractured or loosened to buffer the occlusal overload but in Bicon models such buffering effect is not expected, so in Bicon model, load can be concentrated in alveolar bone area.

기전 시스템의 구동 모터 선정 방법과 견마로봇용 지뢰탐지 구동 장치에의 적용

최창환,정승호,김석환,이정엽,최덕선,정상철,박용운,Choi, Chang-Hwan,Jung, Seung-Ho,Kim, Seok-Hwan,Lee, Jeong-Yeob,Choe, Tok-Son,Chung, Sang-Chul,Park, Yong-Woon 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.4

This paper presents a motor selection technique for a manipulator design that is used in a multipurpose dog-horse robot. Since the dynamics of a manipulator and its servo drives are closely related to each other, it requires a repetitive analysis to determine a suitable motor. In order to simplify this procedure, Straete et al. proposed a simple normalization method to separate the load dependent terms and the motor dependent terms. This technique is adopted in this paper for selecting a motor in designing a manipulator.

아프리카 국제개발협력 지원 결정요인 분석

최창환(Chang-Hwan Choi) 한국무역학회 2013 貿易學會誌 Vol.38 No.5

골풀 부위별 추출물의 항산화 효과

최창환 ( Chang Hwan Choi ),원두현 ( Doo Hyun Won ),황준필 ( Jun Pil Hwang ),박수남 ( Soo Nam Park ) 대한화장품학회 2012 대한화장품학회지 Vol.38 No.3

이번 연구에서 우리는 골풀의 부위별 추출물의 항산화 활성을 측정하였다. 골풀의 부위는 상층부와 하층부, 고갱이 부위로 결정하였다. 실험은 골풀 50 % 에탄올 추출물, 에틸아세테이트(ethyl acetate) 분획, 아글리콘(aglycone) 분획 세 가지로 진행하였다. 항산화 활성 중 라디칼인 DPPH (1,1-diphenyl-2- picrylhydrazyl) 소거활성(FSC₅₀)을 살펴본 결과 50 % 에탄올 추출물의 경우 고갱이 부위(42.9 μ g/mL)가, 에틸아세테이트 분획은 지하 부위(12.1 μ g/mL), 아글리콘 분획은 지하 부위(12.1 μ g/mL)가 가장 높은 라디칼 소거능을 나타내었다. Luminol 발광법을 이용한 Fe³⁺-EDTA/H₂O₂ 계에서 생성된 활성산소종에 대한 소거활성(총 항산화능, OSC₅₀)을 살펴본 결과, 50 % 에탄올 추출물은 고갱이 부위(0.29 μ g/mL), 에틸아세테이트 분획은 지하 부위(0.25 μ g/mL), 아글리콘 분획은 고갱이 부위(0.20 μ g/mL)가 가장 높은 총 항산화능을 나타내었다. Rose-bengal로 증감된 ¹O₂에 의한 적혈구 파괴에 대한 세포보호 효과는 10 μ g/mL 농도에서 고갱이 부위의 아글리콘 분획이 τ⁵⁰ 321.0 min으로 가장 높은 세포 보호 활성을 나타내었다. 이와 같은 항산화 효과로 볼 때 골풀의 지하 부분과 고갱이 부위의 추출물은 천연 항산화제로서 여러 산업 분야에 응용 가능할 것이라 생각된다. 특히 높은 τ50 값을 갖는 것으로 보아, 태양광 노출에 의해서 ¹O₂이 많이 생성되는 부위인 피부를 효과적으로 보호해줄 수 있을 것으로 생각되어진다. In this study, the antioxidative effects of extracts from different parts of Juncus effusus L. were investigated. The three parts (above-ground part, below-ground part, medulla part) were selected. 50 % ethanol extract, ethyl acetate and aglycone fractions of J. effusus L. were used in experiments. The highest DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities (FSC₅₀) was shown by medulla part (42.9 μ g/mL) in 50 % ethanol extracts, below-ground part (12.1 μ g/mL) in ethyl acetate fractions, and below-ground part (12.1 μ g/mL) in aglycone fractions. Reactive oxygen species (ROS) scavenging activities (OSC₅₀) on ROS generated in Fe³⁺-EDTA/H₂O₂ system using the luminol-dependent chemiluminescence assay showed the most prominent effect of medulla part (0.29 μ g/mL) in 50 % ethanol extracts, below-ground part (0.25 μ g/mL) in ethyl acetate fractions, and medulla part (0.20 μ g/mL) in aglycone fractions. The cellular protective effects of extract/fractions of J. effusus L. on the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner (0.5 ∼ 10 μ g/mL). Especially, aglycone fraction of medulla part at a concentration of 10 μ g/mL showed the most prominent protective effect among all extracts (τ₅₀, 321.0 min). These results indicate that extracts from below-ground part and medulla part of J. effusus L. extracts can be used as an natural antioxidant. Particularly, J. effusus L. can protect suggesting a high τ₅₀ skin where many ¹O₂ was generated by sunlight exposure.

반덤핑 조사개시가 상대국 반덤핑 조치에 어떻게 영향을 주는가?

최창환(Chang-Hwan Choi) 한국국제상학회 2017 國際商學 Vol.32 No.4

This paper analyzes how initiation affect trade measures on the other countries, and the difference between developing and developed countries using panel data. The empirical results show that anti-dumping initiations have a more positive effect on developing countries s anti-dumping measures than on developed ones. And unemployment, GDP has a less negative effect on anti-dumping measures in developing counties than in developed countries. FDI has a adverse effect on anti-dumping measures in developing countries. In order to avoid anti-dumping measures, the developing countries should increase FDI, the developed countries shall improve unemployment and GDP growth. 본 논문에서는 반덤핑 조사개시가 상대국의 반덤핑 조치에 어떻게 영향을 미치는지에 대해 개발도상국과 선진국 그룹으로 나누어 패널자료를 통해 비교 분석하였다. 실증분석 결과를 살펴보면, 반덤핑 조사개시는 선진국 그룹보다는 개발도상국의 반덤핑 조치에 보다 더 큰 영향을 미치는 것으로 확인되었다. 이는 개발도상국이 상대국에서 반덤핑 조치를 위한 조사개시가 실시되면 즉각적인 보복조치를 취할 가능성이 높다는 점을 보여 주었 다. 실업률, 경제성장률 등의 거시경제변수들은 선진국의 반덩핑 조치에 보다 더 큰 영향을 미친 것으로 확인되었고, 해외직접투자의 경우에는 개도국에 더 큰 영향을 미친 것으로 확인되 었다.

궤양성 대장염의 임상경과 진단 첫해의 임상경과에 영향을 미치는 인자 및 5 년간 임상경과의 변화 양상

최창환(Chang Hwan Choi),정혜원(Hae Won Chung),이재훈(Jae Hoon Lee),박정엽(Jeong Youp Park),이현웅(Hyun Woong Lee),박영수(Young Soo Park),김태일(Tae Il Kim),김원호(Won Ho Kim) 대한소화기학회 2001 대한소화기학회지 Vol.38 No.3

Background/Aims: Previous reports on ulcerative colitis in Korea were mostly about clinical features at the time of diagnosis. In this study, we analyzed not only clinical features of Korean patients with ulcerative colitis at the time of diagnosis, but also clinical courses during 5 years after diagnosis. Methods: The yearly sum of monthly symptom scores (annual disease burden index, ADBI), annual symptomatic period, and clinical severity were evaluated during 5 years after diagnosis, and factors affecting the clinical courses during first year were also analyzed. Results: The averages of ADBI, symptomatic period, and the proportion of patients in remission during the first follow-up year were 5.8±4.4, 4.0±3.1 months, and 22.1%, Those were 3.7±4.1, 3.0±3.4 months, and 32.4%, during the fifth year. The average of ADBI during the second year was significantly higher in patients with high ADBI (>4) during the first year compared with that in patients with low ADBI (6.3±5.5 vs. 2.6±3.8, p<0.01). Conclusions: From these results, we can conclude that the clinical course of ulcerative colitis, assessed by ADBI and symptomatic period, tends to improve with time and the preceding clinical course is significantly correlated to subsequent course. (Korean J Gastroenterol 2001;38: 169-176)

태권도 지식검사의 정보매체에 따른 차별적 문항기능검증: 멀티미디어 및 지필검사의 다언어 집단비교

최창환(Chang Hwan Choi),박재현(Jae Hyeon Park),이재봉(Jae Bong Lee),이미영(Mi Young Lee),김혜진(Hyeoi Jin Kim) 한국체육측정평가학회 2012 한국체육측정평가학회지 Vol.14 No.1

이 연구는 최창환, 이재봉, 박재현, & 김혜진(2010)의 후속연구로써 다언어로 개발된 지필형 검사와 멀티미디어형 검사의 차별적으로 기능하는 문항을 추출하여 그 특성을 분석함으로써 검사정보매체들이 갖는 고유한 측정학적 특성을 확인함을 목적으로 수행되었다. 이 목적을 위하여 한국의 서울, 경기지역 90명과 미국의 로스엔젤레스 지역 99명, 총 189명의 태권도 유단자를 대상으로 최창환 등(2010)이 개발한 지필형 그리고 멀티미디어형 태권도 지식검사를 실시하였다. 검사정보매체에 따른 측정학적 특성을 분석하고자 기술통계와 차별적 기능문항(differential item functioning : DIF)을 산출하였으며, DIF 추출방법을 위해 Mantel-Haenszel 방법을 적용하였다. 기술통계치 산출과 차별적 기능문항을 추출하기 위하여 R 통계 프로그램(package-``dif-R``, 2.13. ver)을 활용하였다. 분석결과, 총 80개의 태권도 지식검사 문항에서 아홉 개의 차별기능문항이 추출되었다. 추출된 아홉 개 문항 중 여섯 개 문항이 지필형에서 추출되었으며, 세 개 문항은 멀티미디어형에서 추출되었다. 지필형 검사에서 추출된 여섯 개 문항은 모두 한국 태권도 유단자들에게 유리하게 기능하는 문항으로 나타나 멀티미디어형 검사가 언어에 따른 문항의 편파성을 줄일 수 있는 것으로 확인되었다. 또한 차별적 문항으로 추출된 지필형 여섯 개 문항은 대부분 문항의 지문이 길게 구성된 특징을 가지고 있었다. 이는 언어 문화권이 다른 집단에게 번안된 검사를 수행할 때 지필형 검사보다 멀티미디어형 검사가 유용할 수 있음을 시사한다. 결론적으로 멀티미디어형 정보매체가 체육 및 스포츠영역에서 요구하는 지식을 측정할 때, 문항이 가지고 있는 정보의 전달이 명확할 뿐 아니라 다언어 집단을 대상으로 측정하고자 할 때 검사의 편파성을 줄일 수 있는 것으로 요약할 수 있다. The knowledge tests using multimedia contents have been successfully applied in many areas such as education, medicine, or technology. Despite there are a lot of advantages using multimedia contents for testing of knowledge in physical education or sports performance setting, the tests based on paper and pencil are widely used in the physical education and sports. Choi, Park, Lee and Kim(2010) developed a knowledge test program for Taekwondo based on multimedia contents(MC) and paper contents(PC) in Korean and translated into English ver. When being translated into different languages, the measurement equivalence of the adapted instrument should be assessed, because the original translated instruments may not be equivalent. The purpose of this study is to identify the differential item functioning(DIF) of the Taekwondo knowledge test. For this study, a total of 189 taekwondo trainees from Seoul area in Korea and California area in USA(KOR : 90 trainee, USA : 99 trainee). A 80 items for taekwondo knowledge were developed with equivalent form(40 items for MC and PC, respectively) and obtained content validity evidence by experts of taekwondo and measurement specialists. All of the items were classified into one of four sub-domains of taekwondo(basic motion, kyorugi, poomsae, and demonstration of taekwondo). One of the statistic methods for differential item functioning was Mantel-Haenszel(Holland & Thayer, 1988) based on differential item functioning. and the R computer program(package of "dif-R", 2.13. ver) was used as data analysis. As a result, 9 items(PC : 3, 5, 12, 18, 31, 34 and MC : 6, 7, 22) were showed statistically significant of differential item functioning(p<.05). 6 items of PC(3, 5, 12, 18, 31, 34) and 1 item of MC(no.22) test were in favor of Korean and 2 items of MC(6, 7) test were in favor of American Taekwondo trainees(p<.05).