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.

Effects of Dilute Acid Pretreatment on Enzyme Adsorption and surface Morphology of Liriodendron tulipifera

Byeong Cheol Min,Bon Wook Koo,Ki Seob Gwak,Hwan Myeong Yeo,Joon Weon Choi,In Gyu Choi 한국목재공학회 2011 목재공학 Vol.39 No.2

In this study, dilute acid pretreatment of Liriodendron tulipifera was performed for enzymatic hydrolysis. As the pretreatment temperature was increased, enzymatic hydrolysis and enzyme adsorption yield also increased. The highest enzymatic hydrolysis yield was 57% (gig) and enzyme adsorption was 44% (gig). Enzymatic hydrolysis yield was determined with weight loss of pretreated biomass by enzyme, and enzyme adsorption was a percentage of enzyme weight attaching on pretreated biomass compared with input enzyme weight. When L. tulipifera was pretreated with 1% sulfuric acid at 160℃ for 5 min., hemi-cellulose was significantly removed in pretreatment, but the lignin contents were constant. Other changes in surface morphology were detected on biomass pretreated at 160℃ by a field emission scanning electron microscope (FESEM). A large number of spherical shapes known as lignin droplets were observed over the entire biomass surface after pretreatment. Hemicellulose removal and morphological changes improved enzyme accessibility to cellulose by increasing cellulose exposure to enzyme. It is thus evidence that enzyme adsorption is a significant factor to understand pretreatment effectiveness.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

실내 스모그 챔버의 설계 및 성능평가

배귀남,김민철,이승복,송기범,진현철,문길주 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.4

A multi-functional indoor smog chamber was designed and evaluated lo investigate photochenical or water vapor reaction mechanisms of air pollutants. Various smog chamber experiments could be conducted using ambient air or purified air in this smog chamber. The smog chamber consisted of a housing, a Teflon bag, blacklights, injection ports, sampling ports, and utility facilities. The characteristics of light source, the wall losses of air pollutants, and the quality of purified air were experimentally investigated. The maximum NO₂ photolysis rate was 1.10min^(-1). In a 2.5-m³ Teflon bag, the wall losses of ambient O₃, NO, and NO₂were 1.2~2.4×10^(-3)min^(-1), 0.7~2.0×10^(-3)min^(-1), and 0.4-2.0×10^(-3)min^(-1), respectively. The wall loss of ambient particles ranging 0.05 to 0.2㎛ was 1.8~5.4×10^(-3)min^(-1), which was slightly higher than those of ambient gaseous species. The purified air supply system provided high quality of air with NO₂, < 1 ppb, and total hydrocarbons <5 ppb.

The Korean Association of lnternal Medicine : Poster Session ; PS 1357 : Nephrology ; Age is the Strongest Effector for the Relationship between Estimated Glomerular filtration Rate and Coronary Artery Calcifi cation in Apparently Healthy Korean Adults

( Hyun Beom Chae ),( Eun Jung Rhee ),( Hae Jung Park ),( Min Kyung Lee ),( Won Seon Jeon ),( Se Eun Park ),( Cheol Young Park ),( Won Young Lee ),( Ki Won Oh ),( Sung Woo Park ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Cardiovascular disease (CVD) is a major clinical problem and the most common cause of morbidity and mortality in patients with chronic kidney disease (CKD). Coronary artery calcifi cation (CAC) is a potential mechanism that explains the association between renal function and cardiovascular mortality. We aimed to evaluate the association between renal function and CAC in apparently healthy Korean subjects. Methods: In 23,617 participants in the health screening program in Kangbuk Samsung Hospital health screening program from January 2010 to December 2011, estimated glomerular fi ltration rate (eGFR) was assessed by Cockcroft-Gault equation. Coronary artery calcium score (CACS) was measured by multi-detector computed tomography (MDCT). Subjects were divided into 3 groups according to the CKD Staging system with eGFR grade; stage 1: eGFR = 90 mL/min/1.73 m2, stage 2: eGFR 60-89 mL/ min/1.73 m2, stage 3: eGFR 30-59 mL/min/1.73 m2. Results: Mean age of the participants was 41.4 years, and mean eGFR was 103.6±21.7 mL/min/1.73 m2. Hypertension and diabetes were noted in 43.7% and 5.5% of the participants, respectively. eGFR showed weakly negative but signifi cant association with CACS in bivariate correlation analysis (r=-0.076, p<0.01). Mean CACS signifi cantly increased from CKD stage 1 to 3. The proportion of subjects who had CAC signifi cantly increased from CKD stage 1 to 3. Although odds ratio for CAC signifi cantly increased from stage 1 to 3 after adjustment for confounding factors, this signifi cance was inversed when age was included in the model. Age was the strongest factor that affects CAC. Conclusions: This study performed in young Korean subjects with relatively normal renal function, age was the mostly strongest effector on the association between eGFR and the degree of CAC.

시공간 트렐리스 부호화 CDMA 시스템에서의 선택적 PRC를 사용한 레이크 수신기의 성능 분석

기영민,임은정,안철용,김동구,이석규 延世大學校 電波通信共同硏究所 2002 電波通信論文誌 Vol.6 No.1

다중 경로 페이딩 채널에서의 시공간 트렐리스 부호 (STTC, Space-Time Trellis Codes)의 성능 열화를 보완하기 위한 시공간 등화기는 수신기를 복잡하게 하는 단점이 있다. 본 논문에서는 PRC (Principal Ratio Combining) 레이크 수신기를 제안하였다. 이 수신기는 다중 경로 신호를 PRC 기법을 사용하여 컴바이닝 함으로서 수신 SINR (Signal to Interference and Noise Ratio)을 개선하는 효과를 얻는다. 또한, 본 논문에서는 모든 다중 경로 컴바이닝에 비교하여, 낮은 복잡도로 비슷한 성능을 얻을 수 있는 선택적 PRC (Hybrid Selection / Principal Ratio Combining) 구조를 제시하였다. The space-time equalizer has been used to enhance the space time code in the multipath fading channel. However it requires higher receive complexity. In this paper, the principal ratio combining (PRC) receiver for space-time trellis coded CDMA system is proposed in the multipath fading channels. It maximizes the received signal to interference and noise ratio (SINR) and reduces the complexity of the system compared to optimum ML receiver. We also present the hybrid selection / principal ratio combining (HS/PRC) scheme that can achieve the performance comparable to that of the full path PRC combining system.

에이즈 환자에서 발생한 조류형결핵균 뇌수막염 1예

이기덕,박완범,정혜승,강철인,김동민,김홍빈,오명돈,최강원 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

에이즈 환자의 중추신경계 합병증으로 에이즈 바이러스 자체에 의한 합병증, 기회감염, 종양 등이 있다. 저자들은 전신긴장간대발작을 일으킨 31세 남자 에이즈 환자에 발생한 조류형결핵균 뇌수막염을 조직학적 및 미생물학적으로 증명하고, 항비결핵미코박테리아 약제를 고농도로 투여하여 치료하였다. 조류형결핵균 뇌수막염은 결핵성 뇌수막염으로 잘못 진단되면 치명적인 결과를 초래할 수 있으므로, 조직검사를 포함한 적극적인 검사가 필요하다. We report a case of Mycobacterium avium-intraceliuiarae meningoencephalitis found in a 31-year-old patient with AIDS and preexisting disseminated Mycobacterium avium-intracellularae infection. He had been taking highly active antiretroviral therapy and antimycobacterial medications when he developed generalized tonic-clonic seizure. Repeated workups including blood and cerebrospinal fluid examinations and magnetic resonance image (MRI) of the brain revealed nondiagnostic. The diagnosis was made by stereotactic brain biopsy of the nodule, which was detected 9 month after the first seizure attack in brain MRI. Acid-fast bacilli were observed on microscopic exam. Mycobacterium avium-intracellularae was isolated from the biopsy specimen.

만성 부비동염 환자에서 부비동 내시경수술 후 후각기능의 호전

나기상,신광철,김용민 충남대학교 의과대학 지역사회의학연구소 1999 충남의대잡지 Vol.26 No.2

Few studies on the outcome of endoscopic sinus surgery have assessed the effect of this treatment on the sense of smell. We have collected data prospectively on 30 patients with bilateral chronic sinusitis, before and 8 weeks after surgery. Patients were asked after surgery whether their sense of smell was normal, better, a little better, the same, or worse. Olfactory detection thresholds were obtained using butanol sniff bottles. Subjective sensation of olfaction was improved in 70%, the same in 30% of patients. However, olfactory threshold score was improved in 50%, the same in 32%, and worse in 18% postoperatively. Normosmic nose was found in 10% before surgery. 26.7% showed hyposmic, and 63.3% were anosmic before surgery. The postoperative butanol test showed that 11.7% was normosmic, 50% hyposmic and 38.3% anosmic. Preoperative butanol threshold scores were lower as the severity of sinusitis increased while the degree of postoperative improvement showed no correlation with the severity of sinusitis. Cases of primary surgery showed higher preoperative butanol threshold scores and more pronounced postoperative improvement than cases of revision surgery. The results of this study suggest that impairment of olfaction in chronic sinusitis may be significantly improved following endoscopic sinus surgery.

ICT를 활용한 일본어 교육에서 문장 표기 형식이 영상문자 낭독 및 내용 파악에 미치는 효과

강신철,김민기 한국컴퓨터교육학회 2004 컴퓨터교육학회 논문지 Vol.7 No.6

본 연구에서는 프로젝션 TV와 컴퓨터 화면에 제시되는 일본어 영상문자 읽기 수업을 위한 적합한 화면 환경을 살펴보았다. 그리고 복수표기, 띄어쓰기 등 실제 일본 웹 사이트에 나타나는 일본어 표기 형식에 대한 사전 학습활동이 웹 문서의 내용 파악에 어떠한 영향을 미치는지를 실험을 통해 살펴보았다. 실험 결과 제7차 교육과정에 새롭게 추가된 일본 웹 문서의 독해 능력을 배양하기 위하여 두 가지 조치가 필요함을 알 수 있었다. 단기적으로는 실제 일본어 웹 사이트의 문서를 학습 자료로 활용할 필요가 있으며, 장기적으로는 현행 일본어 교과서의 표기 형식을 재검토할 필요가 있음을 확인할 수 있었다. We investigated the proper display environment for Japanese electronic character reading lessons through the experiment with a projection TV and a computer. For the purpose of finding out the effect of prior learning activities at the context of authentic Japanese text orthography, which includes dual notation, words spacing, etc., we also made an experiment on comprehending the web documents which are extracted from Japanese web sites. From the experimental results, we acquired a conclusion that two approaches are needed to enhance the ability of comprehending Japanese web documents which is newly added to the 7th curriculum revision. For short-term approach, we need to utilize Japanese web documents as learning materials. For long-term approach, we have to reconsider whether the orthography of the current Japanese textbooks is suitable or not.

논토양중 카드뮴 유효도와 수도의 흡수이행에 미치는 석회 및 Humic acid 사용효과

김민경,김원일,정구복,박광래,윤순강,엄기철 한국환경농학회 2004 한국환경농학회지 Vol.23 No.1

토양중 중금속이 식물에 흡수 및 이행되는 것을 경감시켜 여기에서 생산된 농산물의 안전성 향상을 위한 기초자료를 확보하고 논토양의 카드뮴 유효도와 흡수이행에 미치는 석회와 humic acid 처리 효과를 구명하기 위하여 실내경험과 포트실험을 수행하였다. 실내실험에서 공시토양에 2.5와 5.0 ton/ha의 석회와 1%와 2% humic acid를 처리한 후 토양중 가용성 카드뮴 함량 변화를 조사한 결과, 두 처리 모두 14일까지는 담수상태에서 처리효과로 인하여 가용성 카드뮴 함량이 감소하다가 그 이후에는 토양의 완충능에 의해 다시 증가하는 경향이었다. 이때, 토양의 가용성 카드뮴 함량은 토양 pH 및 양이온치환용량과 부의 상관이 있었다. 2.5 ton/ha의 석회와 1% 의 humic acid를 처리한 후 담수시켜 안정화된 다음 벼를 재배하여 조사한 결과, 석회와 humic acid 처리에 비해 분얼기와 수확기의 치화태 및 수용태 카드뮴 함량이 낮아졌으나, 분얼기에 비해 수확기에 토양중 이동이 어려운 산화물 및 탄산염태와 황화물 및 잔류태의 함량이 증가하였다. 식물에 흡수가 용이한 형태로 알려진 치환태와 수용태는 모두 토양 pH와 고도의 부의 상관이 있었다. 수확기의 줄기, 잎 및 현미 건물중은 석회 및 humic acide 처리구에서 대조구에 비해 모두 높았고, 특히 석회 처리구의 건물중이 현저하게 높았다. 석회 처리구에서 줄기와 잎의 카드뮴 함량은 각각 1.01과 0.37㎎/㎏으로 대조구와 비슷하였으나, 뿌리나 현미의 카드뮴 ?량은 각각 2.11과 0.09㎎/㎏으로 대조구에 비해 낮았다. 지상부와 뿌리의 카드뮴 함량은 humic acid 처리에 의해 현저히 낮아졌으며, 특히 현미로의 카드뮴 이행도 월등히 낮게 나타난다. This study was conducted to know the effect of lime and humic acid on cadmium availability and its uptake by plant grown in contaminated paddy soils with heavy metal. The treatment levels of lime were 2.5 and 5.0 ton/ha and that of humic acid were 1 and 2%. The contents of 0.1 N HCl extractable Cd were reduced with lime and humic acid and were negatively correlated with CEC as well as soil pH. The sequential extraction procedure was used to fractionate the heavy metals in soil into the designated from exchangeable (0.5 M KNO₃), water soluble (H₂O), organically bound (0.5 M NaOH), carbonate (0.05 M Na₂-EDTA) and sulfide/residual (4 M HNO₃). In soil amended with 2.5 ton/ha lime and 1% humic acid, chemical forms of Cd at tillering stage were predominant exchangeable+water soluble extractable Cd, whereas that at harvesting stage were predominant carbonate+sulfide/residual extractable Cd. The exchangeable forms of Cd in soil with lime and humic acid were negatively correlated with soil pH during the harvesting period. Total absorbed Cd of paddy rice tended to occur in the order of root > stem > leaf > brown rice. Cd con- tents of brown rice with lime and humic acid treatment were 0.09 and 0.08 mg/kg, respectively. That were lower than control, 0.20 ㎎/㎏. It could be that treatment of lime and humic acid in polluted soil by heavy metals would reduce the uptake of heavy metals by plants and be a temporary method of reclamation at the highly heavy metal contaminated soils.