In-stent area stenosis on 64-slice multi-detector computed tomography coronary angiography: optimal cutoff value for minimum lumen cross-sectional area of coronary stents compared with intravascular ultrasound

Kwon, Woocheol,Choi, Jiyoun,Kim, Jang-Young,Kim, Seong-Yoon,Yoon, Junghan,Choe, Kyoung-Hoon,Lee, Seung Hwan,Ahn, Sung Gyun Springer-Verlag 2012 The international journal of cardiovascular imagin Vol.28 No.1

The Effect of Mineral Trioxide Aggregate on the Production of Growth Factors and Cytokine by Human Periodontal Ligament Fibroblasts

Kwon, JiYoon,Lim, SungSam,Baek, SeungHo,Bae, KwangShik,Kang, MyungHoe,Lee, WooCheol 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.3

이 연구의 목적은 치주인대 섬유아세포에 MTA를 접촉시킨 뒤 성장인자 transforming growth factor-betal (TGF-β1), fibroblast growth factor-2 (FGF-2) 및 cytokine interleukin-6 (IL-6)의 발현량 변화를 측정하는 것이다. MTA군에서는 100 mg씩의 ProRoot MTA와 증류수를 혼합하고, IRM군은 동량의 IRM 분말을 용액에 혼합하여, 이 시료들을 경화반응이 진행되도록 7일간 놓아두었다. 사람의 치주인대 섬유아세포를 배양하여 MTA와 TRM 시료 상에 well당 1×10^(5)개 수준으로 도포한 뒤 6, 12, 24, 48시간 동안 배양하였다 (n = 5). 대조군으로는 재료의 접촉 없이 배양한 세포를 사용하였다. 시료에서 상c층액을 분리하여 TGF-β1, FCF-2, IL-6의 발현량을 enzyme-linked immunosorbent assay (ELISA)법으로 측정하였다. MTA군에서, 성장인자인 TGF-β1과 FGF-2는 대조군에 비해 유의성 있게 발현이 억제되었으며 (p<0.05), cytokine인 IL-6 발현량은 대조군과 유사한 수준으로 나타났다. Mineral trioxide aggregate (MTA) would influence healing of periapical tissues by modulating the production of growth factors and cytokines from PDL fibroblasts, however, the studies are insufficient. Therefore, the purpose of this study was to monitor the expression of transforming growth factor-betal (TGF-β1), fibroblast growth factor-2 (FGF-2), and interleukin-6 (IL-6) from PDL fibroblasts in the presence of MTA. The human PDL fibroblasts were seeded onto the set MTA or IRM at a level of 1×10^(5) cells per unit well, and further incubated for 6, 12, 24, and 48 hours. The levels of TGF-β1, FGF-2, and IL-6 from the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). The data were analyzed using one-way ANOVA. The level of TGF-β1 was down-regulated when the cells were grown in the presence of MTA except at 6 hours. The levels of FGF-2 release were significantly suppressed when PDL fibroblasts were grown in the presence of MTA or IRM at all time intervals (p<0.05). The expressions of IL-6 from MTA treated cells were comparable to those of untreated control cells throughout the observation periods. We presume that this material inhibits the stimulatory function of growth factors on granulation tissue formation and in turn, it promotes the healing process modulated by other bone-remodeling cells. [J Kor Acad Cons Dent 32(3):191-197, 2007]

임베디드 SRAM의 Built-in Access Time 측정 회로 설계

신우철(Woocheol Shin),백경일(Kyungil Baek),정현섭(Hyunsub Jung),여정현(Junghyun Yo),권건태(Geuntae Kwon),이윤종(Yoonjong Lee) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.11

In this paper, we propose the built-in digital logic architecture and method for measuring the access time of embedded SRAMs. The proposed built-in architecture for access time measurement can be designed with only CMOS STD cell libraries and implemented using the auto placement and route techniques, which enables the proposed architecture to be applied in other process technologies. The built-in architecture makes it possible to measure the access timing using automated method without human errors and additional errors from the external measurement equipment. The proposed architecture can measure the timing with the precision of tens of picoseconds by using an accurate delay control scheme. The function and timing of the proposed logic were verified using logic simulations and a silicon test chip with DongBu Hitek 0.13um process.

Imaging Assessment of Visceral Pleural Surface Invasion by Lung Cancer: Comparison of CT and Contrast-Enhanced Radial T1-Weighted Gradient Echo 3-Tesla MRI

Zhang Yu,Kwon Woocheol,Lee Ho Yun,Ko Sung Min,Kim Sang-Ha,Lee Won-Yeon,Yong Suk Joong,Jung Soon-Hee,Byun Chun Sung,Lee JunHyeok,Yang Honglei,Han Junhee,Ackman Jeanne B. 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.5

Objective: To compare the diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3-tesla (3T) magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of visceral pleural surface invasion (VPSI). Visceral pleural invasion by non-small-cell lung cancer (NSCLC) can be classified into two types: PL1 (without VPSI), invasion of the elastic layer of the visceral pleura without reaching the visceral pleural surface, and PL2 (with VPSI), full invasion of the visceral pleura. Materials and Methods: Thirty-three patients with pathologically confirmed VPSI by NSCLC were retrospectively reviewed. Multidetector CT and contrast-enhanced 3T MRI with a free-breathing radial three-dimensional fat-suppressed volumetric interpolated breath-hold examination (VIBE) pulse sequence were compared in terms of the length of contact, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. Supplemental evaluation of the tumor-pleura interface (smooth versus irregular) could only be performed with MRI (not discernible on CT). Results: At the tumor-pleura interface, radial VIBE MRI revealed a smooth margin in 20 of 21 patients without VPSI and an irregular margin in 10 of 12 patients with VPSI, yielding an accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F-score for VPSI detection of 91%, 83%, 95%, 91%, 91%, and 87%, respectively. The McNemar test and receiver operating characteristics curve analysis revealed no significant differences between the diagnostic accuracies of CT and MRI for evaluating the contact length, angle of mass margin, or arch distance-to-maximum tumor diameter ratio as predictors of VPSI. Conclusion: The diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3T MRI and CT were equal in terms of the contact length, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. The advantage of MRI is its clear depiction of the tumor-pleura interface margin, facilitating VPSI detection.

가상훈련 콘텐츠 만족도 측정도구 개발 및 타당화

양미석 ( Miseok Yang ),김우철 ( Woocheol Kim ),권오영 ( Ohyoung Kwon ) 한국실천공학교육학회 2023 실천공학교육논문지 Vol.15 No.1

본 연구는 가상훈련 학습자의 가상훈련 콘텐츠 활용 만족도를 측정하는 도구 개발 및 타당화하는 것이 목적이다. 이를 위해 K대학교 온라인평생교육원에서 2011년부터 2022년까지 가상훈련 만족도로 활용한 문항을 토대로 기초문항을 도출하였다. 이후, K대학교 온라인평생교육원 포털 STEP에 접근한 학습자를 대상으로 온라인 설문조사를 실시하여 성실하게 응답한 총 491부를 최종분석에 사용하였다. 최종 사용한 491부의 자료는 기초문항분석, 탐색적 요인분석, 신뢰도 분석, 확인적 요인분석 등의 방법으로 분석하였다. 첫째, 기초문항분석에서 평균 4점이상, 왜도 ±2, 첨도 ±4이상의 수용기준을 벗어난 문항은 없었다. 둘째, 탐색적 요인분석 실시 후 도출된 가상훈련 콘텐츠 만족도 하위요인별 상관계수는 r=.682 ~ .822(p<.01)로 나타나 양호하였다. 하위요인별 신뢰도 계수는 콘텐츠 내용 .849, 콘텐츠 활용 .922, 시스템 및 운영지원 .841, 활용지속의향 .920, 전체신뢰도는 .956로 매우 높게 나타났다. 셋째, 확인적 요인분석 결과, 구성개념도는 .842 ~ .926로 나타나 추천기준치인 .7보다 높았으며, 평균분산추출도 .640 ~ .796으로 나타나 추천기준치인 .5보다 높아 각각 구성개념에 대한 대표성을 갖고 있다고 볼 수 있다. 가상훈련 학습자의 콘텐츠 만족도 구인 타당성을 검증한 결과로 콘텐츠 내용, 콘텐츠 활용, 시스템 및 운영지원, 활용지속의향 등 4개 요인 모형이 도출되었다. 본 연구는 가상훈련 학습자의 콘텐츠 만족도 측정도구를 실증적으로 개발하여 준거 틀과 기준을 제공했다는데 의의가 있다. The purpose of this study is to develop and validate a tool that measures the satisfaction of virtual training learners’ use of virtual training content. To this end, 491 copies of the basic questions derived from the satisfaction questions used by the K University Online Lifelong Education Center were used for the final analysis by conducting an online survey of learners who accessed STEP, the K University Online Lifelong Education Center portal. The 491 copies of data finally used were analyzed by methods such as basic question analysis, exploratory factor analysis, reliability analysis, and confirmatory factor analysis. First, in the basic question analysis, there were no questions that exceeded the acceptance criteria of an average of 4 points or more, skewness ±2, and kurtosis ±4. Second, the correlation coefficient for each sub-factor of virtual training content satisfaction derived after exploratory factor analysis was good as r=.682 to .822 (p<.01). The reliability coefficient for each sub-factor is content .849, content utilization .922, System and Operations Support .841, Intention to Continue Utilization .920, the overall reliability is. It was very high at .956 Fifth, as a result of confirmatory factor analysis, the compositional conceptual diagram is. It was .842 to .926, higher than the recommended standard of .7, and the average variance extraction degree. It appears to be .640 to .796, higher than the recommended standard of .5, which can be seen as representative of each constituent concept. As a result of verifying the validity of virtual training learners’ content satisfaction recruitment, four factor models were derived: content substance, content utilization, system and operation support, and intention to continue use. This study is meaningful in that it empirically developed a tool to measure content satisfaction of virtual training learners and provided a reference frame and criteria.

The Effects of Bronchoscope Diameter on the Diagnostic Yield of Transbronchial Lung Biopsy of Peripheral Pulmonary Nodules

Lee, Nakwon,Kim, Sang-Ha,Kwon, Woocheol,Lee, Myoung Kyu,Yong, Suk Joong,Shin, Kye Chul,Jung, Ye-Ryung,Choi, Yeun Seoung,Choi, Jiwon,Choi, Ji Sun,Lee, Won Yeon The Korean Academy of Tuberculosis and Respiratory 2014 Tuberculosis and Respiratory Diseases Vol.77 No.6

Background: Transbronchial lung biopsy (TBLB) is a valuable diagnostic tool for peripheral pulmonary lesions. The diagnostic yield of TBLB reportedly ranges from 41%-60%. Many studies demonstrated the various factors that influence the yield of TBLB, including size, location, and distance from the carina or pleura. However, no study has evaluated the effects of the bronchoscope diameter. We evaluated whether the bronchoscope diameter affected the diagnostic yield of TBLB. Methods: We reviewed records from 178 patients who underwent TBLB using bronchoscopes of two different diameters (5.7 mm, thick outer diameter, Olympus BF-200; 4.9 mm, thin, BF-260). The fluoroscopic guidance rates, yield of TBLB and flexible bronchoscopy (FB) were compared between the two groups. Additionally, we compared the results of the procedures with respect to diagnosis, distance from the pleura, and size of the lesion. Results: The results of fluoroscopic guidance, TBLB, and FB yield using thin diameter bronchoscope were significantly better than those obtained with a thick diameter bronchoscope (p=0.021, p=0.036, and p=0.010, respectively). Particularly, when the distance from the pleura was ${\leq}10mm$, success rates for fluoroscopic guidance and FB with thin bronchoscope were higher (p=0.013 and p=0.033, respectively), as compared to with thick bronchoscope. Conclusion: A thinner diameter bronchoscope increased the yield of bronchoscopy, and bronchial washing in conjunction with TBLB was useful in the diagnosis of peripheral pulmonary nodules.

직업능력개발훈련 교·강사의 자격연계형 마이크로 크리덴셜 적용 방안

양미석 ( Miseok Yang ),권오영 ( Ohyoung Kwon ),김우철 ( Woocheol Kim ) 한국실천공학교육학회 2023 실천공학교육논문지 Vol.15 No.1

본 연구는 직업능력개발훈련 교·강사의 보수교육과정을 살펴보고, 마이크로 크리덴셜을 적용하기 위한 방안을 살펴보기 위해 수행되었다. 이를 위해 K대학교 능력교육개발원의 직업능력개발훈련 교·강사의 보수교육과정 현황, 마이크로 크리덴셜의 특징, 보수교육과정과 마이크로 크리덴셜의 연계가능성을 살펴보고, 스타훈련교사의 인터뷰를 실시하여 분석한 결과는 다음과 같다. 첫째, 디지털 인증서에 대한 인식은 훈련과정 이수시 디지털 인증서인 디지털 크레딧, 디지털 뱃지 발급과 보수교육의 공인된 자격과정에 대한 인식은 대부분 긍정적으로 인식하고 있었다. 또한, 보수교육의 마이크로 크리덴셜 적용방안으로 다양한 사례로 보수교육보다 혜택을 주는 방안, 보수교육의 체계화, 자격과정의 체계화 및 등급화, 자격과정의 학점화 등을 제안하였다. 둘째, 마이크로 크리덴셜을 적용한 보수교육 활용성 제고를 위한 제도적 보완장치로 NCS기반 전공 보수교육 확대 필요성, 효율적인 학습콘텐츠와 학습방법 제공, 최소 이수시간 설정 등을 언급하였다. 그리고, 직업능력개발훈련 교·강사의 이해도 제고방안으로 가장 많이 응답한 내용은 마이크로 크리덴셜 홍보방안이었다. 셋째, 보수교육기관과 직업능력개발훈련 교·강사의 역할에서 보수교육기관은 교육품질 유지에 대해 가장 많이 언급하고 있으며, 직업능력개발훈련 교·강사의 역할로 가장 많이 응답한 내용은 적극적 참여였다. 본 연구로 직업능력개발훈련 교·강사의 보수교육과정과 마이크로 크리덴셜 간의 자격연계로 전문성 제고와 실무역량 이력 포트폴리오를 실질적으로 제공할 수 있는 직업훈련 환경구축을 기대한다. This study was conducted to examine the remuneration curriculum of vocational ability development training teachers and instructors and to examine ways to apply micro credentials. To this end, the current status of the remuneration curriculum of vocational ability development training instructors and instructors at K University’s Competency Education Development Institute, the characteristics of micro credentials, and the possibility of linking the remuneration curriculum to micro credentials are as follows. First, most of the recognition of digital certificates was positive for digital certificates such as digital credit, digital badge issuance, and recognition of the recognized qualification process of maintenance education when completing the training course. In addition, as a method of applying micro credentials to conservative education, various cases were proposed to benefit from conservative education, systematization and grading of the qualification process, and credit of the qualification process. Second, as an institutional supplement to enhance the utilization of conservative education using micro credentials, the need to expand NCS-based major conservative education, provide efficient learning contents and learning methods, and set minimum completion time. In addition, the most common response as a way to improve the understanding of teachers and instructors in vocational ability development training was the micro credential promotion plan. Third, in the role of conservative education institutions and vocational ability development training instructors and instructors, conservative education institutions mention maintaining educational quality the most, and active participation was the role of vocational ability development training instructors. Through this study, it is expected to establish a vocational training environment that can enhance expertise and provide a practical portfolio of practical competency history by linking the remuneration curriculum of vocational competency development training instructors and micro credentials.

CASE REPORT : Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report

( Yeun Seoung Choi ),( Jung Soo Lim ),( Woocheol Kwon ),( Soon Hee Jung ),( Il Hwan Park ),( Myoung Kyu Lee ),( Won Yeon Lee ),( Suk Joong Yong ),( Seok Jeong Lee ),( Ye Ryung Jung ),( Jiwon Choi ),( 대한결핵 및 호흡기학회 2015 Tuberculosis and Respiratory Diseases Vol.78 No.4

Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus.

Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report

Choi, Yeun Seoung,Lim, Jung Soo,Kwon, Woocheol,Jung, Soon-Hee,Park, Il Hwan,Lee, Myoung Kyu,Lee, Won Yeon,Yong, Suk Joong,Lee, Seok Jeong,Jung, Ye-Ryung,Choi, Jiwon,Choi, Ji Sun,Jeong, Joon Taek,Yoo, The Korean Academy of Tuberculosis and Respiratory 2015 Tuberculosis and Respiratory Diseases Vol.78 No.4

Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus.

Development of a chest digital tomosynthesis r/f system and implementation of low‐dose gpu‐accelerated compressed sensing (cs) image reconstruction

Choi, Sunghoon,Lee, Haenghwa,Lee, Donghoon,Choi, Seungyeon,Lee, Chang‐,Lae,Kwon, Woocheol,Shin, Jungwook,Seo, Chang‐,Woo,Kim, Hee‐,Joung Published for the American Association of Physicis 2018 Medical physics Vol.45 No.5