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      • KCI등재

        촉매를 이용한 이산화탄소 고정화 및 고리형 카보네이트 합성반응에 대한 계산화학적 해석

        안혜영(Hye Young An), 김민경(Min-Kyung Kim), 정희철(Hui Cheol Jeong), 엄기헌(Ki Heon Eom), 원용선(Yong Sun Won) 한국청정기술학회 2016 청정기술 Vol.22 No.1

        본 연구에서는 이론화학 또는 분자모델링이라 불리는 계산화학을 기존에 연구된 촉매반응 실험결과를 해석하는 데 접목시켜 보았다. 온실효과의 주범인 이산화탄소를 에폭사이드와 반응을 통해 고정화하고 카보네이트를 생성하는 반응을 선택하였는데 이 반응은 활성화 에너지(55~59 kcal/mol)가 높아 촉매의 사용이 불가피하다. 많은 기존 연구들 중에 ZIF-90/ionic liquid immobilized ZIF-90 (IL-ZIF-90), polystyrene-supported quaternized ammonium salt, KI/KI-glycine, dimethylethanolamine (DMEA)를 촉매로 사용한 경우에 대해 반응의 각 단계를 계산하여 반응의 경로를 예측하고 단계별로 구한 에너지를 바탕으로 에너지도를 구성함으로써 실험결과를 열역학적으로 해석하였다. ZIF-90/IL-ZIF-90과 KI/KI-glycine의 경우는 실험적으로 후자들이 상대적으로 높은 수율을 얻었는데 계산 결과 활성화에너지가 낮아진 이유가 아니라 전자들의 경우 반응 중간체가 높은 에너지를 가져 반응물로 되돌아가는 역반응에 의해 정반응의 진행이 방해를 받은 것으로 밝혀졌다. DMEA를 촉매로 사용하였을 경우는 활성화 에너지를 ~42 kcal/mol로 낮춰줌으로써 금속이나 할로겐염 없이도 촉매의 활성이 잘 일어남을 증명하였다. 폴리스티렌(polystyrene)으로 지지된 quaternized 암모늄염 촉매의 경우 클러스터 가정을 사용하여 계산을 진행하였으며 암모늄염의 -NH기와 에폭사이드의 O 원자 사이의 상호작용의 가능성을 확인할 수 있는 반응경로를 제시하였다. In this study, a computational chemistry methodology called as molecular modeling was been applied to explain several experiment results mechanistically. The reaction chosen for this study was to remove carbon dioxide, known as a primary greenhouse gas, by an epoxide via the carbon dioxide fixation to produce carbonates. This reaction inherently needs the use of catalysts because it has a significantly high activation barrier (55~59 kcal/mol). Among various types of catalysts, we studied in zeolitic imidazolate framework 90 (ZIF-90)/ionic liquid immobilized ZIF-90 (IL-ZIF-90), polystyrene-supported quaternized ammonium salt, KI/KI-glycine, and dimethylethanolamine (DMEA). First, probable reaction pathways were proposed based on calculated energetics by computational chemistry. The energetics was then used for the thermodynamic interpretation on the activity of catalysts. In the case of ZIF-90/IL-ZIF-90 and KI/KI-glycine, IL-ZIF-90 and KI-glycine showed better yields compared to their counterparts. The calculation proposed interesting results that it is not from the lowering of activation energy but from the unstable intermediates of ZIF-90 and KI-glycine. For DMEA, the calculated activation energy was ~42 kcal/mol, much lower than that of the non-catalytic reaction. A possible reaction pathway was located to confirm the interaction between -NH group from ammonium and oxygen from epoxide for polystyrene-supported quaternized ammonium salt.

      • SCOPUSKCI등재

        원저 : 직장 카르시노이드 종양에서 Ki-67 발현의 예후적 중요성

        홍수민 ( Su Min Hong ), 김유선 ( You Sun Kim ), 문정섭 ( Jung Seop Moon ), 김진남 ( Jin Nam Kim ), 오명기 ( Myoung Ki Oh ), 권선옥 ( Sun Ok Kwon ), 정성연 ( Seong Yeon Jeong ), 홍성우 ( Seong Woo Hong ), 강윤경 ( Yun Kyung Kang ) 대한소화기학회 2013 대한소화기학회지 Vol.61 No.2

        Background/Aims: Rectal carcinoid tumors can be resected with endoscopy, and it is important to assess their prognostic factors. We evaluated the potential of Ki-67 expression as a prognostic factor in rectal carcinoid tumors. Methods: We retrospectively reviewed the medical records of 37 patients with rectal carcinoid tumors who got endoscopic resection from January 2001 to January 2011 at Inje University Seoul Paik Hospital. We analyzed their endoscopic and histologic findings, Ki-67 expression, clinical outcome, and prognosis. Results: The mean age (±SD) of the patients was 56.3±10.7 years, and the male : female ratio was 3.6:1. The mean tumor size was 0.5±0.4 cm, 33 patients showed grade 1 tumors (89.2%) and the average Ki-67 expression was 0.7±1.2%. Thirty five patients underwent endoscopic mucosal resection, and two required endoscopic submucosal dissection. Eight patients had positive margins after resection, but no cases of lymphovascular invasion were identified. The median follow-up duration was 21.4±25.4 months, and no recurrences were observed. Conclusions: In low grade rectal carcinoid tumors which are lack of central depression on colonoscopy, the expression of a molecular marker of malignant potential, Ki-67, was low. Therefore, endoscopic resection seemed to be a safe and effective treatment for these tumors.

      • SCOPUSKCI등재

        Large cell acanthoma의 임상 및 병리 조직학적 소견과 Ki-67 발현 양상

        김상태,서기석,정해홍 대한피부과학회 1999 大韓皮膚科學會誌 Vol.37 No.9

        Background : 1970, Pinkus described large cell acanthoma(LCA) as a benign epidermal neoplasm which clinically resembles a actinic keratosis or seborrheic keratosis. However, the entity of this disease is still unclear. Objective : The purpose of this study was to find out if LCA is a distinctive entity by investigating its clinical features, histopathologic features and Ki-67 expreesion. Methods : 20 LCA samples including normal tissue were analyzed after investigating their clinicopathologic features and immunohistochemical analysis of Ki-67 expression which was performed on the formalin-fixed, praffin-embedded tissue section. The assessment of immunohistochemical staining was based on the growth fraction(GF), defined as the number of Ki-67 positive cells divided by the total number of tumor cells counted, and was expressed in a percentage. Results : 1. LCA was usually presented as a well demarcated, brown or light brown, 5 to 30 mm, round, flat to hyperkeratotic scaly patch and plaque. It predominantly affected female(5.6 female : 1 males) againg from 37 to 76 years of age(mean 51 year0old). The duration of LCA ranged from 6 months to 30 years. In eleven cases, the lesion was located on the face and in nine cases, on the extremities. Eight cases showed a solitary lesion and twelve cases showed multiple lesions. Transformation to malignancy was not found. 2. Histopathologic study showed sharply circumscribed epidemal neoplasms characterized by large(approximately twice the normal size) uniform keratinocytes with proportinally large nuclei and an increase of melanin in the basal layer. In many cases, hypergranulosis(18 cases) and hyperkeratosis(17 cases) were observed. Occasionally, acanthosis(10 cases), papillomatosis(9 cases) and epidermal atrophy(7 cases) were also observed. However, keratinocyte necrosis was not observed. Moderate solar elastosis and moderate lymphocytic infiltration was observed in the upper part of the dermis in all cases. Mild and moderate melanin incontinence was observed in 14 cases and 1 case respectively. Appendage involvement(follicular infundibulum and acrosyringium) was observed in all cases. 3. The Ki-67 expression of LCA tissue(4.87±3.10%) was significantly higher than the adjacent Ki-67 strongly suggests that LCA is a distinctive entity. (Korean J Dermatol 1999;37(9) : 1261∼1268)

      • SCIESCOPUSKCI등재

        원저 : 식도의 원주상피 피복 점막에서 점액유전자 발현 및 세포증식능에 대한 연구

        최석채 ( Suck Chei Choi ), 김용성 ( Yong Sung Kim ), 김기훈 ( Ki Hoon Kim ), 김헌수 ( Hun Soo Kim ), 조향정 ( Hyang Jeong Jo ), 윤기중 ( Ki Jung Yun ) 대한소화관운동학회 2007 Journal of Neurogastroenterology and Motility (JNM Vol.13 No.1

        목적 : 바렛식도는 지속적인 위식도역류 등으로 원위부 식도에 정상적으로 존재하는 편평상피세포 대신에 배상세포를 포함하는 장형 원주세포로 식도 점막이 피복되는 것을 말한다. 그리고 이형성을 거쳐 선암종으로 진행할 수 있기 때문에 이형성 이전 단계인 바렛식도의 발암과정에 대한 연구가 필요하다. 이에 바렛식도와 배상세포를 포함하지 않은 원주세포만 있는 식도를 대조군으로 하여 점액유전자 및 세포증식능에 대해 비교 연구하였다. 대상 및 방법 : 임상 및 내시경적으로 바렛식도가 의심되어 원위부 식도에서 생검한 환자들 중에서 배상세포가 있어 조직학적으로 바렛식도로 증명된 25명의 환자와 배상세포가 없었던 환자들 중에서 무작위로 선택한 30예를 대조군으로 하였다. 생검 당시의 나이와 성별 그리고 MUC1, MUC2, Ki-67에 대한 면역조직화학적 염색을 시행하였다. 결과 : 바렛식도의 평균 나이 및 남자 비율은 각각 65.3±10.1세, 76.0%이였고, 대조군의 평균 나이 및 남자 비율은 각각 53.0±14.8세, 60.0%로 바렛식도의 나이가 대조군식도보다 의의있게 높았다. MUC1은 바렛식도 및 대조군 모두에서 100% 발현되었고, MUC2 발현율은 바렛식도 및 대조군에서 각각 92%, 20%이었다. Ki-67 발현율은 바렛식도 및 대조군에서 각각 80.0%, 70.0%이였고, Ki-67 발현 강도의 평균은 바렛식도 1.20±0.76, 대조군 0.77±0.57로 발현 강도에서 바렛식도가 의의있게 높았다. 결론 : 바렛식도는 원주세포만 있는 식도에서 보다 좀더 지속적인 위식도역류 등의 자극으로 생긴다. 그리고 MUC2는 주로 바렛식도에서 발현되고 세포증식능은 바렛식도에서 좀더 높으며 이는 MUC2 발현과 관련될 수 있다고 생각된다. Background/Aims: Barrett`s esophagus is characterized by the presence of metaplastic columnar epithelium with goblet cells in the distal esophagus. Barrett`s esophagus progresses through low grade dysplasia and high grade dysplasia to adenocarcinoma. We studied the patient age, the mucin gene and the proliferation activity of biopsy-proven Barrett`s esophagus and simple columnar epithelium-lined esophagus. Methods: To evaluate the mucin gene expression and proliferation activity, twenty five cases of Barrett`s esophagus and thirty cases of control esophagus were examined immunohistochemically with using the monoclonal antibodies to MUC1, MUC2 and Ki-67. Results: The Barrett`s esophagus patients were older (mean: 65.3±10.1 years) than the control patients (mean: 53.0±14.8 years). The MUC1 expression was 100% in both Barrett`s esophagus and the control esophagus. An MUC2 expression was observed in 92.0% of the Barrett`s esophagus and 20.0% of the control esophagus. The rate and intensity of the Ki-67 expression was higher in the Barrett`s esophagus (80.0%, 1.20±0.76) than that in the control esophagus (70.0%, 0.77±0.57). Conclusions: Barrett`s esophagus is a metaplastic lesion due to the more long-standing gastroesophageal reflux than that in a simple columnar epithelium-lined esophagus. The cause of increased proliferation activity in Barrett`s esophagus may be related to the MUC2 expression. (Kor J Neurogastroenterol Motil 2007;13:21-25)

      • Deployment Expectation of Q-mark Model for Quality

        Jeong-Hyun,Park,Jin-Sam,Kim,Ki-Hong,Kim 보안공학연구지원센터 2015 International Journal of Software Engineering and Vol.9 No.1

        This paper presents Q-mark model which is for quality of R&D projects in ETRI since 2008. The model has the simplified tailoring processes with selection & concentration based on ISO/IEC 12207 & 15288 for quality of R&D projects. There are 5 processes for quality of R&D projects in Q-mark model such as the requirement definition process [RDP] as staring point of project, testing process [TP] as ending point of project, inspection as peer review & requirement tracing phase between RDP and TP, project execution management process with WBS, issue, and risk management, and configuration management and quality assurance process for quality of R&D products such as documents and development technology. There are also survey results such as R/D product's quality upgrade level, technology transfer and business impacts, and improvement consideration as deployment expectation of Q-mark model in this paper. The Q-mark model has been adapted and improved continuously for quality upgrade of R&D projects, and inner and outer customer satisfaction of products.

      • SCOPUSKCI등재

        Determination of Hydrogen Peroxide on Modified Glassy Carbon Electrode by Polytetrakis(2-aminophenyl)porphyrin Nanowire

        Jeong,,Hae-Sang,Kim,,Song-Mi,Seol,,Hee-Jin,You,,Jung-Min,Jeong,,Eun-Seon,Kim,,Seul-Ki,Seol,,Kyung-Sik,Jeon,,Seung-Won Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

        Nanowires of polytetrakis(o-aminophenyl)porphyrin (PTAPPNW) were fabricated by electrochemical polymerization with the cyclic voltammetric method in anodic aluminum oxide (AAO) membranes. The glassy carbon electrode (GCE) modified by PTAPPNW, single-walled carbon nanotubes (SWNT) and Nafion as a binder was investigated with voltammetric methods in a phosphate buffer saline (PBS) solution at pH 7.4. The PTAPPNW + SWNT + Nafion/GCE exhibited strongly enhanced voltammetric and amperometric sensitivity towards hydrogen peroxide ($H_2O_2$), which shortened the response time and enhanced the sensitivity for $H_2O_2$ determination at an applied potential of 0.0 V by amperometric method. The PTAPPNW + SWNT + Nafion/GCE can be used to monitor $H_2O_2$ at very low concentrations in biological pH as an efficient electrochemical $H_2O_2$ sensor.

      • KCI등재SCOPUS

        Coordinated Voltage and Reactive Power Control Strategy with Distributed Generator for Improving the Operational Efficiency

        Ki-Seok,Jeong,Hyun-Chul,Lee,Young-Sik,Baek,Ji-Ho,Park 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

        This study proposes a voltage and reactive coordinative control strategy with distributed generator (DG) in a distribution power system. The aim is to determine the optimum dispatch schedules for an on-load tap changer (OLTC), distributed generator settings and all shunt capacitor switching on the load and DG generation profile in a day. The proposed method minimizes the real power losses and improves the voltage profile using squared deviations of bus voltages. The results indicate that the proposed method reduces the real losses and voltage fluctuations and improve receiving power factor. This paper proposes coordinated voltage and reactive power control methods that adjust optimal control values of capacitor banks, OLTC, and the AVR of DGs by using a voltage sensitivity factor (VSF) and dynamic programming (DP) with branch-and-bound (B&B) method. To avoid the computational burden, we try to limit the possible states to 24 stages by using a flexible searching space at each stage. Finally, we will show the effectiveness of the proposed method by using operational cost of real power losses and voltage deviation factor as evaluation index for a whole day in a power system with distributed generators.

      • KCI등재SCOPUS
      • KCI우수등재

        Analysing Korean Residential House Tenure Choice by Mixed Logit Panel Model

        Jeong,,Ki-Ho,Lee,,Sang-Ho 한국데이터정보과학회 2008 한국데이터정보과학회지 Vol.19 No.2

        This paper analyzes Korean residential tenure choice for house which is the most important in Korean households' assets. Data used in the analysis is the data of Korean Labor and Income Panel Study for the period from 1998 to 2006 and with 2341 households. In this paper, a household chooses a housing tenure mode, either by renting or by owing house. We use a mixed-logit panel model as an estimation model to take into consideration household's heteroscedasticity of preference in tenure choice. It turns out that the heteroscedasticity is significant in households' tenure choice behavior, implying that Korean housing policy emphasizing supply side should consider the demand side.

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