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      • KCI등재

        Ki-67 labeling index as a prognostic marker in advanced stomach cancer

        Sang Hyuk Seo,Kwang Hee Kim,Sang Hoon Oh,Yunseon Choi,Ki Jung Ahn,Ji Young Lee,Sang Min Lee,박지선,Woo Gyeong Kim 대한외과학회 2019 Annals of Surgical Treatment and Research(ASRT) Vol.96 No.1

        Purpose: Proliferation marker Ki-67 is widely used in cancer prognosis prediction. We tried to investigate the role of Ki-67 as a prognostic factor in stomach cancer after surgery in this study. Methods: We retrospectively evaluated 251 patients who underwent curative resection for gastric cancer from 2010 to 2015. In pathologic examination, Ki-67 labeling index was defined as the percentage of Ki-67 antigen positive cells. Prognostic significance of Ki-67 for gastric cancer was evaluated. Disease-free survival (DFS) was assessed as a primary end-point. Results: The median follow-up period was 28.0 months. Thirty-one patients (12.4%) showed Ki-67 labeling index (LI) lower than 25%. Sixty-eight patients (26.6%) showed recurrence during follow-up period. Recurrence was associated with Ki- 67 LI level (≤25%, P = 0.016), and lymph node metastasis status (P = 0.002). High Ki-67 LI level (>25%) was also related to p53 positivity (P < 0.001) and poorly cohesive type (P = 0.002). The 3-year DFS was 69.4%. Low Ki-67 LI level (≤25%) was related with low DFS (47.6% vs. 72.6%, P = 0.016). T stage (P < 0.001), N stage (P = 0.006), lymphovascular invasion (P = 0.010), and neuronal invasion (P = 0.001) also affected the DFS. In addition, T stage (P = 0.03) and Ki-67 LI (P = 0.035) were independent prognostic factors for DFS. In patients treated with adjuvant chemotherapy (n = 239, 93.4%), low Ki-67 (≤25%) was a poor prognostic factor for DFS (P = 0.013). Conclusion: Low Ki-67 LI predicts high rate of progression and low DFS of stomach cancer. Ki-67 LI can be a predictive marker in resected stomach cancer treated with surgery and adjuvant chemotherapy.

      • SCOPUSKCI등재

        KI-180과 KI-188 칼슘조성물이 어린쥐의 성장발육에 미치는 영향

        박승만(Seung-Man Park),성기승(Ki-Seung Seong),이종석(Jong-Seok Lee),이옥환(Ok-Hwan Lee),한찬규(Chan-Kyu Han) 한국식품과학회 2014 한국식품과학회지 Vol.46 No.3

        본 연구에서는 KI-188 칼슘과 KI-180 조성물이 성장발육에 미치는 효과를 조사하였다. 시험기간중 KI-188 칼슘과 KI-180 식이군이 대조군 보다 성장률과 평균 식이섭취량은 증가하였다. 체장은 KI-188 칼슘과 KI-180 식이군이 대조군에 비해 평균 3.55 mm 더 길었고, 등뼈길이는 KI-180 식이군이 대조군 보다 통계적인 차이는 없었지만 0.5 mm 더 길었다. 대퇴골 무게는 KI-188 칼슘과 KI-180 식이군이 대조군에 비해 통계적으로 무거웠으며, 대퇴골길이는 대조군에 비해 각각 평균 0.89, 1.09 mm 더 길었다. 혈당, 총콜레스테롤 및 중성지방 농도는 차이가 없었고, 칼슘농도는 KI-188 칼슘과 KI-180 식이군 보다 대조군이 유의하게 높았다. 백혈구와 혈소판수는 차이가 없었고, 적혈구, 혈색소 및 헤마토크릿치는 대조군이 KI-188 칼슘과 KI-180 식이군 보다 통계적으로 높았다. ALP활성은 KI-180 식이군이 대조군 보다 통계적으로 높았고, osteocalcin농도는 KI-188 칼슘과 KI-180 식이군이 대조군에 비해 통계적으로 유의하게 높았다. 혈청 testosterone 농도는 KI-188 칼슘과 KI-180 식이군과 대조군 간에 차이가 없었다. IGF-1과 IGFBP-3 농도는 KI-180 조성물이 대조군 보다 각각 20%, 11% 정도 유의하게 더 높았다. 이상의 결과를 검토할 때 KI-188 칼슘과 KI-180 조성물은 어린쥐의 성장과 골격의 발달을 촉진시키고, 성장호르몬의 분비능을 양적으로 유도하여 전반적인 성장발육에 유효한 작용이 있는 것으로 사료된다. Herbs have active components that promote the growth rate of both animals and human. The KI-180 and KI-188 calcium food formulae contain Acanthopanacis cortex, Bombysis corpus and hoelen, seaweed calcium, chlorella extract, spirulina, colostrum powder, and other natural and functional components. We evaluated the growth-promoting effects of these formulae by analyzing the weight, femur and backbone, alkaline phosphatase, osteocalcin, testosterone, insulin-like growth factor (IGF)-1, and IGF binding protein-3 (IGFBP-3) of growing rats. Growing rats administered with KI-180 and KI-188 calcium showed the increase of body weight, body length, and femur weight and length of growing rats. In addition, administration of KI-180 and KI-188 calcium increased the alkaline phosphatase activity, the levels of osteocalcin and the growth hormones IGF-1 and IGFBP-3 of growing rats. The impact of KI-180 and KI-188 calcium on the physical development of growing rats suggests that the incorporation of these food formulae in the diets of growing children may promote the physical development.

      • KCI등재SCOPUS
      • SCIESCOPUSKCI등재

        위 아전절제술 후 십이지장 위 역류성 위염에서 p53 및 Ki-67 단백 발현 양상

        최석채 ( Suck Chei Choi ),김용성 ( Yong Sung Kim ),김기훈 ( Ki Hoon Kim ),김헌수 ( Hun Soo Kim ),윤기중 ( Ki Jung Yun ) 대한소화기기능성질환·운동학회 2007 Journal of Neurogastroenterology and Motility (JNM Vol.13 No.2

        목적 : 십이지장 위 역류성 위염은 위절제 등에 의해서 발생하는 것으로 후에 암종이 발생할 가능성이 높은 것으로 알려져 왔다. 그러나 사람에서 십이지장 내용물의 역류와 암종 발생 사이의 병인론적 연구가 흔하지 않다. 이에 십이지장 위 역류성 위염을 보이는 환자의 조직과 대조군 환자의 조직을 대상으로 Ki-67 및 p53 단백 발현 정도를 측정하여 상피 세포증식 유도 및 암억제 유전자의 발현 정도를 비교 연구하였다. 대상 및 방법 : 위암종으로 위아전절제술을 받은 총 57예 중 내시경 및 조직학적으로 십이지장 위 역류성 위염으로 진단된 16예의 내시경 조직과 대조군 16예의 내시경 조직을 대상으로 하여 Ki-67 및 p53 단백 발현을 면역조직화학적 염색을 하였고 그 강도를 점수화하였다. 결과 : 십이지장 위 역류성 위염 소견을 보인 환자의 내시경적 추적 기간은 평균 607일, 대조군 556일 그리고 57예의 평균은 471일로 유의한 차이는 없었다. 십이지장 위 역류성 위염 환자의 Ki-67 발현 강도의 중간값은 3.0로 대조군 중간값 2.0보다 의미있게 높았으며, p53 단백의 발현 강도 중간값도 2.0으로 대조군 중간값 1.0 보다 의미있게 높았다. 결론 : 십이지장 위 역류성 위염은 담즙 등이 점막의 상피세포 증식을 유도하고 유전자 이상을 초래할 가능성이 높아 시간 경과 후 암종이 발생할 가능성이 대조군에 비해서 높을 수 있음을 알 수 있었다. Background/Aims: Duodenogastric reflux of bile and other contents of duodenum is one of the main etiologic fators in chronic gastritis, and chronic inflammation has been recognized as a risk factor of human cancer. The aim of this study was therefore to evaluate the expression of p53 and Ki-67 protein in duodenogastric reflux gastritis. Methods: To evaluate the proliferation activity and tumor suppressor gene expression, 16 cases of duodenogastric reflux gastritis and 16 cases of control gastric tissue after subtotal gastrectomy were examined immunohistochemically using the monoclonal antibodies to Ki-67 and p53 protein. Results: The mean duration of follow-up endoscopic biopsy after subtotal gastrectomy was 607 days in duodenogastric reflux gastritis and 556 days in control groups. The mean intensity of Ki-67 in duodenogastric reflux gastritis was significantly higher than that of control tissues (3.0 vs 2.0). The mean intensity of p53 protein in duodenogastric reflux gastritis was significantly higher than that of control tissues (2.0 vs 1.0). Conclusions: The high expressions of Ki-67 and p53 protein in duodenogastric reflux gastritis may be one of the main mechanisms in the development of gastric stump carcinoma. (Kor J Neurogastroenterol Motil 2007;13:118-122)

      • KCI등재

        Interobserver Variability of Ki-67 Measurement in Breast Cancer

        정율리,장민혜,박소연,공경엽,정우희,이지신,The Korean Breast Pathology Ki-67 Study Group 대한병리학회 2016 Journal of Pathology and Translational Medicine Vol.50 No.2

        Background: As measurement of Ki-67 proliferation index is an important part of breast cancer diagnostics, we conducted a multicenter study to examine the degree of concordance in Ki-67 counting and to find factors that lead to its variability. Methods: Thirty observers from thirty different institutions reviewed Ki-67–stained slides of 20 different breast cancers on whole sections and tissue microarray (TMA) by online system. Ten of the 20 breast cancers had hot spots of Ki-67 expression. Each observer scored Ki-67 in two different ways: direct counting (average vs. hot spot method) and categorical estimation. Intraclass correlation coefficient (ICC) of Ki-67 index was calculated for comparative analysis. Results: For direct counting, ICC of TMA was slightly higher than that of whole sections using average method (0.895 vs 0.858). The ICC of tumors with hot spots was lower than that of tumors without (0.736 vs 0.874). In tumors with hot spots, observers took an additional counting from the hot spot; the ICC of whole sections using hot spot method was still lower than that of TMA (0.737 vs 0.895). In categorical estimation, Ki-67 index showed a wide distribution in some cases. Nevertheless, in tumors with hot spots, the range of distribution in Ki-67 categories was decreased with hot spot method and in TMA platform. Conclusions: Interobserver variability of Ki-67 index for direct counting and categorical estimation was relatively high. Tumors with hot spots showed greater interobserver variability as opposed to those without, and restricting the measurement area yielded lower interobserver variability.

      • SCOPUSKCI등재

        간내 담석과 동반된 간내 담도암에서의 p53과 Ki-ras의 발현

        김명환,이성구,서동완,이승규,남승우,박능화,민영일,김연석,심기남,공경엽 대한소화기학회 1997 대한소화기학회지 Vol.30 No.5

        Background/Aims: Hepatolithiasis or primary intrahepatic stones may be accompanied later by intrahepatic cholangiocarcinoma. This cancerous lesion is frequently associated with atypical hyperplastic epithelium that was suspected of being precancerous. To investigate the Ki-ras or p53 mutation may play a role in carcinogenesis, and to determine whether atypical hyperplastic epithelium may be precancerous, this study was performed in intrahepatic cholangiocarcinomas associated with hepatolithiasis. Methods: We examined 12 patients with intrahepatic cholangiocarcinomas associated with hepatolithiasis. Ki-ras point mutations were assessed by direct DNA sequencing. Expressions of p53 protein were immunohistochemically assessed. The overexpression of p53 and point mutation of Ki-ras were examined in normal, hyperplastic, atypical hyperplastic, and can- cerous tissues separately. Results: The expressions of p53 protein were detected in 4 (33%) of 12 cholangiocarcinomas and Ki-ras point mutations at codon 12 were found in 2 (17%) of 12 cholangiocarcinomas. In those two carcinoma cases which contained the mutant sequence of Ki-ras, the same point mutation from wild type GGT (glycine) to GAT (aspartic acid) was. found in the associated atypical hyperplastic epithelium. However, none of the normal and hyperplastic epithelium harbored Ki-ras or p53 mutations. Conclusions: The overexpression of p53 may play a part in the carcinogenesis of some intrahepatic cholangiocarcinomas associated with hepatolithiasis, whereas the role of Ki-ras mutations in those cases is dubious. However, Ki-ras point mutation at codon 12 may be responsible for either cancer or atypical hyperplastic epithelium associated with hepatolithiasis in certain cases, suggesting atypical hyperplastic epithelium may give rise to carcinoma.

      • KCI등재

        김기림·조향의 시론에 나타난 몽타주 기법

        이기주 ( Lee Ki-ju ) 한국현대문예비평학회 2017 한국문예비평연구 Vol.- No.53

        본 연구는 영화의 기법인 몽타주(montage) 이론의 국내 수용 과정과 몽타주 이론이 1930년대 이후 김기림, 조향과 같은 시인들에게 어떻게 작용하였는지를 밝히는 것을 목적으로 한다. 1930년대는 본격적으로 영화 이론이 국내로 수용된 시기였으며, 이는 사회주의 이데올로기의 영향, 새로운 이론에 대한 호기심 등이 복합적으로 작용한 결과였다. 1930년대 서광제, 오덕순과 같은 인물들은 베르토프, 푸도프킨, 티모셴코, 에이젠슈테인 등과 같은 소비에트 영화이론가들의 저작들을 번역, 소개하였고 이는 김기림을 비롯한 1930년대 모더니즘 시인들에게 영향을 끼쳤다. 김기림은 계급문학운동을 부정하면서 모더니티의 시적 추구작업에 몰입했고 I.A 리차즈의 영향을 받아 과학주의적 방법론을 시론에 도입 하였다. 김기림은 `구성`이라는 개념으로 `새로운 시`의 창작기법을 나타낸다. 구성은 인공성이 강조된 기법으로 글을 건축학적으로 조립하는 것이다. 이와 같은 특성은 몽타주와 동일하다. 김기림의 시론에서 몽타주 이론은 고도의 지성적인 구성을 갖춘 혁명적인 방법론이었으며, 이러한 건축학적 설계는 에이젠슈테인의 `시각적인 대위법`과 유사성을 지니는 음악적 방법론이다. 조향은 김기림의 `영화시` 개념을 시에 적용시킨다. 김기림이 과학적 접근을 통해 모더니즘을 받아들였듯이, 조향도 과학적인 면에 천착한다. 그는 큐비즘의 방법론을 끌어와 자신의 시를 설명한다. 큐비즘의 `이동`과 `연결`의 자유는 데페이즈망에서 이질적인 사물들이 배치되어 있는 형태이며, 큐비즘의 동시성을 통해 자신의 시에서 몽타주 기법을 구현하려고 하였다. The present research aims to investigate how the montage theory was introduced to Korea, and to shed light on how it influenced poets such as Kim Ki-rim and Cho Hyang. 1930s was the era when film theories were actively introduced to Korea. This was the result of both socialist ideologies and the curiosity of new theories interacting together. In the 1930s, figures such as Seo Gwang-je and Oh Deok-soon translated and introduced the works of Soviet film theorists such as Vertov, Pudovkin, Timoshenko, and Eisenstein, influencing modernist poets of the era such as Kim Ki-rim. Kim Ki-rim was immersed in the poetic pursuit of modernity while denying the proletarian literary movement and employed scientific methodology to poetry, influenced by I. A. Richards. Kim Ki-rim expressed the creative technique of "new poetry" with the concept of "composition". The "composition" is to assemble the text architecturally with an emphasis on artificiality. This characteristic is also shared by montage. In Kim Ki-rim`s theory, montage was a revolutionary methodology with a highly intellectual composition. This architectural design is a musical methodology which is similar to Eisenstein`s "visual counterpoint". Cho Hyang applied Kim Ki-rim`s concept of "cinema poetry" to poems. Similar to Kim Ki-rim who accepted modernism through a scientific app roach, Cho Hyang sticks to scientific aspects. He explains his poetry by drawing the methodology from Cubism. Cubism`s freedom of "movement" and "connection" takes the form of objects arranged in depaysement. Through the synchronicity of Cubism, Cho Hyang attempted to realize the montage technique in his poetry.

      • Comparison of controlled ovarian stimulation outcomes for fertility preservation in women with breast cancer according to KI-67, histologic grade, pathologic type, and cancer stage

        ( Eun Ji Oh ),( Yeon Hee Hong ),( Seul Ki Kim ),( Jung Ryeol Lee ),( Byung Chul Jee ),( Chang Suk Suh ),( Seok Hyun Kim ) 대한산부인과학회 2020 대한산부인과학회 학술대회 Vol.106 No.-

        Objective: This study aims to analyze that specific prognostic factors such as Ki-67 value, histologic grade, pathology type, and cancer stage can affect controlled ovarian stimulation outcomes(COS) for fertility preservation in women with breast cancer. Methods: This retrospective cohort study included 92 patients with breast cancer aged 21-44 who underwent COS from August 2012 to April 2020, excluding patients with previous gonadotoxic therapy history. All COS cycles were conducted letrozole-combined random start GnRH antagonist protocol. COS outcomes were compared according to prognostic factors;Ki-67 (< 30% vs. ≥ 30%), histologic grade (low vs. high), and pathologic type (intraductal carcinoma(IDC) vs. triple-negative breast cancer(TNBC)), and cancer stage (early (I, II) vs. advanced (III, IV)). Multivariate analysis was also conducted to find any parameter that can impact over 10 mature oocytes acquisition. Results: Among the 92 patients, 42 were Ki-67≥30% compared to 49 of Ki-67<30%. The number of oocytes, and initial mature oocytes were comparable between Ki-67<30% and ≥30 group. The maturation rate was significantly higher in Ki-67≥30% group than Ki-67<30% group (57.4±36.8% vs. 44.8±28.3%, p=0.041). The same results were drawn when divided according to IDC or TNBC. The maturation rate was significantly higher in TNBC than the IDC group (73.0±17.6% vs. 47.0±28.1% p=0.001). However, the histologic grade or stage did not show any difference in COS outcomes between high and low grade or early and advanced stages. With multivariate analysis, age and AMH are parameters associated with the acquisition of over 10 mature oocytes (OR 0.863, 95% CI [0.755-0.987], OR 1.408, 95% CI [1.145-1.732], respectively). Conclusion: Either Ki-67 or pathologic type can be a potential reliable marker for predicting COS outcome, especially maturation rate. Further study with larger sample size with specific conditions is necessary to clarify the correlation between breast cancer prognostic factors and COS outcomes.

      • SCOPUSSCIEKCI등재

        Comparison of Proliferative Activity in Each Histological Subtypes of Benign and Atypical Intracranial Meningiomas by PCNA and Ki-67 Immunolabeling

        최승진,장은덕,권성오,계대곤,박춘근,이상원,강준기,Choi, Seung Jin,Chang, Eun Deok,Kwon, Seung Oh,Kye, Dae Kon,Park, Choon Keun,Lee, Sang Won,Kang, Joon Ki The Korean Neurosurgical Society 2000 Journal of Korean neurosurgical society Vol.29 No.9

        목 적 : 양성 뇌수막종에 비하여 이형성 및 악성 뇌수막종이 나쁜 임상적인 예후 및 양상을 보이는 것은 잘 알려져 있으나, 양성 뇌수막종에 있어서 각각의 병리조직학적 아형에 따른 생물학적 양상의 차이에 대해서는 잘 알려지지 않거나 일부 논란이 되고있다. 본 연구에서는 이형성 뇌수막종 및 양성 뇌수막종의 각각의 병리조직학적 아형에 따른 증식능의 차이여부를 알아보고자 PCNA와 Ki-67표지지수를 분석하였다. 방 법 : 본원에서 뇌수막종으로 수술을 시행하여 얻은, 재발을 보여 재수술을 시행한 2례를 포함하여, 파라핀에 포매시킨 27개의 조직을 대상으로 병리학적인 증식능을 분석하기 위해, PCNA에 대한 단일항체 및 MIB-1 단일항체를 이용한 면역조직화학적 염색을 시행하였다. 조직학적 분류상 meningothelial type이 8례, transitional type이 9례, fibroblastic type이 5례였으며, 이형성 수막종이 5례였다. 결 과 : PCNA표지지수의 평균값은 양성 수막종에서 meningothelial type이 $4.82{\pm}5.10%$, transitional type이 $9.01{\pm}4.25%$, fibroblastic type이 $5.66{\pm}5.32%$를 보였으나 이형성 수막종에서는 $27.62{\pm}19.67%$의 높은 지수를 나타냈고, Ki-67 표지지수의 평균값은 양성 수막종의 아형에서 각각 $0.43{\pm}0.85%$, $0.44{\pm}1.08%$, $0.24{\pm}0.18%$를 보이고, 역시 이형성 수막종에서는 $0.84{\pm}0.59%$의 높은 지수를 보였다. 즉, 양성 수막종에서 각각의 아형에 따른 PCNA 및 Ki-67 표지지수는 통계학적으로 의미있는 차이는 없었으나(p>0.05), 이형성 수막종에서는 의미있는 높은 표지지수를 보여(p<0.05) 양성 수막종에서 보다 높은 증식능을 보임을 알 수 있었다. 결 론 : PCNA 및 Ki-67 표지지수를 이용한 증식능의 비교결과, 양성 뇌수막종에서는 각각의 아형에 따른 생물학적 양상이나 예후는 차이가 없을것으로 생각되나, 이형성 수막종에서는 높은 증식능을 보여 이에 대한 예후를 예상할 수 있을것으로 생각되며, 또한 이러한 표지지수가 병리조직학적으로 양성과 이형성의 감별에 많은 도움이 될것으로 사료된다. Objective : The clinical prognosis and biological behavior of atypical and especially malignant meningiomas are well known to be worse than benign meningioma, but the degree of biological aggressiveness in each classical subtypes of benign meningioma is controversy. This study was performed to see whether there is a difference in the proliferative activity between each different histological subtypes of benign meningioma as well as atypical meningioma. Methods : Paraffin-embedded surgical specimens of 27 meningiomas, including two recurrent tumors, were studied to evaluate proliferative activity by immunohistochemical method with monoclonal antibodies to proliferating cell nuclear antigen(PCNA) and MIB-1. The specimens consisted of 8 cases of meningothelial, 9 cases of transitional, 5 cases of fibroblastic subtypes and 5 cases of atypical meningiomas. Results : Mean PCNA labeling indices of meningothelial, transitional and fibroblastic meningiomas were $4.82{\pm}5.10%$, $9.01{\pm}4.25%$ and $5.66{\pm}5.32%$, but that of atypical meningiomas was $27.62{\pm}19.67%$, noting a higher value compared to all three subtypes of benign meningiomas. Mean Ki-67 labeling indices of the above 3 subtypes were $0.43{\pm}0.85%$, $0.44{\pm}1.08%$ and $0.24{\pm}0.18%$, and that of atypical meningiomas was also revealed to be of higher value ($0.84{\pm}0.59%$). PCNA and Ki-67 labeling indices were not statistically different between histological subtypes of benign meningioma(p>0.05), but the differences of both immunolabeling between benign and atypical meningiomas were statistically significant(p<0.05). Conclusion : Immunolabeling of PCNA and Ki-67 in intracranial meningiomas reveals no prognostic difference between meningothelial, transitional and fibroblastic subtypes in classical benign meningiomas by measuring expression of PCNA and Ki-67, but it seems to be helpful in differentiating benign and atypical meningioma, later showing more proliferative activity and biological aggressiveness.

      • 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.

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