선택적 촉매 산화 반응에 의한 황화 수소의 제거 Ⅱ . TiO2 / SiO2 촉매 상에서 황화 수소의 선택적 산화 반응

천승우,박대원,우희철,홍성수,정종식 ( S . W . Chun,D . W . Park,H . C . Woo,S . S . Hong,J . S . Chung ) 한국공업화학회 1996 공업화학 Vol.7 No.4

본 연구는 H₂S를 TiO₂/SiO₂촉매상에서 산소와의 직접 산화 반응을 통해 원소 황의 형태로 제거하는 반응에 관한 것이다. 순수한 TiS₂Ti(SO₄)_2를 사용한 반응 실험과 순수한 TiO₂에 대한 주기적 온도 조작 실험 결과로부터 TiO₂는 황 회수 공정에서 사용되는 촉매의 비활성화의 주원인으로 알려진 sulfation이나 salfidation에 대해 매우 안정한 것으로 나타났다. TiO₂/SiO₂촉매에서 TiO₂의 담지량이 증가함에 따라 H₂S 전화율이 증가하였고, 원소 황의 선택도는 아주 소폭으로 감소하였다. 반응 실험결과 O₂/H₂S의 비가 증가할수록 원소 황의 선택도는 크게 감소하였다. 10 wt.% TiO₂/SiO₂ 촉매는 화학 양론비의 조성(H₂S=5 vol.% O₂=2.5 vol.%)의 반응물에 10 vol.%의 수증기를 첨가한 경우 활성과 선택도가 감소하였으나 여전히 80% 이상의 원소 황 수율을 유지하고 있었다. Selective catalytic oxidation of H₂S to elemental sulfur using TiO₂/SiO₂ catalysts was investigated in this study. The reaction test with pure TiS₂and Ti(SO₄)₂and cyclic temperature operation revealed that TiO₂had a good resistance to sulfation and sulfidation, which are known as the main cause of catalytic deactivation in sulfur recovery process. With the increase of TiO₂loading amount in Tio₂/SiO₂catalysts, the conversion of H₂S increased and the selectivity of elemental sulfur was very slightly decreased. As the ratio of O₂/H₂S increased, the selectivity to elemental sulfur was drastically decreased. In the presence of 10 vol.% water vapor to a stoichiometric mixture of H₂S and O₂(H₂S =5 vol.% O=2.5 vol.%), both activity and selectivity of 10 wt.% TiO₂/SiO₂catalyst are decreased, but it still showed more than 80% of sulfur yield.

선택적 촉매 산화 반응에 의한 황화수소의 제거 1 . 촉매의 개발

천승우,박대원,우희철,홍성수,정종식 ( S . W . Chun,D . W . Park,H . C . Woo,S . S . Hong,J . S . Chung ) 한국공업화학회 1995 공업화학 Vol.6 No.5

본 연구는 H₂S를 산소와의 직접 산화 반응을 통해 원소 황의 형태로 제거하는 반응에서 고농도의 H₂S를 처리할 수 있는 촉매의 개발에 관한 것이다. 최적의 촉매를 개발하기 위해 각 담체와 금속 산화물에 대한 반응성 실험을 실시하였다. 실험 결과 담체로는 Al₂O₃, TiO₂, ZrO₂ 등이 금속 산화물로서는 Fe₂O₃, V₂O_5, SnO₂, Cr₂O₃ 등이 좋은 활성을 보였다. 반응물 중의 산소의 분압 영향과 반응물에 포함되어질 수 있는 물의 영향에 대해서 관찰한 결과 산소의 분압이 높을수록 전화율은 증가하나 황 선택도는 급격히 감소하는 경향을 보였고, 10vol.%의 물을 반응물에 첨가한 경우 전화율과 황 선택도가 동시에 감소하는 경향을 보였다. In this study, development of catalysts far the direct oxidation of hydrogen sulfide to elemental sulfur, specially for the treatment of high concentrantion of H₂S, was investigated. To find out optimum catalysts, a screenig test for various supports and metal oxides was carried out. Among the supports tested, Al₂O₃, TiO₂ and ZrO₂ showed good catalytic activity. Fe₂O₃, V₂O_5, SnO₂ and Cr₂O₃ have been considered to be active metal oxides. The study on the effects of oxygen partial pressure revealed that the conversion of H₂S increased with increasing the ratio of O₂/H₂S, but the selectivity to sulfur was drasctically decreased. Bath of the conversion of H₂S and the selectivity to sulfur were decreased when 10 vol.% of water was added to the mixture of H₂S and oxygen.

PHF2 histone demethylase acts as a tumor suppressor in association with p53 in cancer

Lee, K-H,Park, J-W,Sung, H-S,Choi, Y-J,Kim, W H,Lee, H S,Chung, H-J,Shin, H-W,Cho, C-H,Kim, T-Y,Li, S-H,Youn, H-D,Kim, S J,Chun, Y-S Macmillan Publishers Limited 2015 Oncogene Vol.34 No.22

Plant homeodomain finger 2 (PHF2) has a role in epigenetic regulation of gene expression by demethylating H3K9-Me2. Several genome-wide studies have demonstrated that the chromosomal region including the PHF2 gene is often deleted in some cancers including colorectal cancer, and this finding encouraged us to investigate the tumor suppressive role of PHF2. As p53 is a critical tumor suppressor in colon cancer, we tested the possibility that PHF2 is an epigenetic regulator of p53. PHF2 was associated with p53, and thereby, promoted p53-driven gene expression in cancer cells under genotoxic stress. PHF2 converted the chromatin that is favorable for transcription by demethylating the repressive H3K9-Me2 mark. In an HCT116 xenograft model, PHF2 was found to be required for the anticancer effects of oxaliplatin and doxorubicin. In PHF2-deficient xenografts, p53 expression was profoundly induced by both drugs, but its downstream product p21 was not, suggesting that p53 cannot be activated in the absence of PHF2. To find clinical evidence about the role of PHF2, we analyzed the expressions of PHF2, p53 and p21 in human colon cancer tissues and adjacent normal tissues from patients. PHF2 was downregulated in cancer tissues and PHF2 correlated with p21 in cancers expressing functional p53. Colon and stomach cancer tissue arrays showed a positive correlation between PHF2 and p21 expressions. Informatics analyses using the Oncomine database also supported our notion that PHF2 is downregulated in colon and stomach cancers. On the basis of these findings, we propose that PHF2 acts as a tumor suppressor in association with p53 in cancer development and ensures p53-mediated cell death in response to chemotherapy.

유착에 의한 AGS 및 Hep-G2 세포 표면 구조의 변화

박동규 ( D. K. Park ),전훈재 ( H. J. Chun ),박재홍 ( J. H. Park ),박철희 ( C. H. Park ),진윤태 ( Y. T. Jeen ),이홍식 ( H. S. Lee ),이상우 ( S. W. Lee ),엄순호 ( S. H. Um ),최재현 ( J. H. Choi ),김창덕 ( C. D. Kim ),류호상 ( H. S. Ryu 대한소화기학회 2002 대한소화기학회 춘계학술대회 Vol.2002 No.-

<목적> 최근 H. pylori 유착에 의한 세포 표면 구조의 변화에 관한 연구가 시도되어지고 있으나 actin 의 변화여부 및 그 특성에 관해서는 아직 명확히 정립되지 못한 실정이다. Rho GTPase는 세포 표면의 미세돌기인 microvilli, filopodia 및 membrane ruffle의 형성과 관련이 있으며, 최근 AGS 세포에서 H. pylori가 Rac activation에 의하여 membrane ruffle을 형성한다는 것과 Rac

부신피질의 선종 및 암종이 병발한 Cushing 氏 症候群에 대하여

이창화,전영균,이종,최숙희,백태일,김영건,최정학,박춘식,배진선 대한적십자사 1976 적십자병원지 Vol.3 No.1

Biochemical analysis of recombinant CYP4A11 allelic variant enzymes: W126R, K276T and S353G

Han, S.,Cha, G.S.,Chun, Y.J.,Lee, C.H.,Kim, D.,Yun, C.H. JAPANESE SOCIETY FOR THE STUDY OF XENOBIOTICS 2016 DRUG METABOLISM AND PHARMACOKINETICS Vol.31 No.6

Human CYP4A11 is the major ω-hydroxylase of fatty acids in the liver and kidneys. It produces 20-hydroxyeicosatetraenoic acid as well as hydroxylates fatty acids. In this study, we investigated the biochemical properties of three alleles of CYP4A11: W126R, K276T, and S353G. Site-directed mutagenesis of the wild type CYP4A11 was performed, to construct the W126R, K276T, and S353G variant clones. The CYP4A11 wild type and variant constructs were heterologously expressed in Escherichia coli. CO-binding spectra showed the expression of the wild type, K276T and S353G variants, indicating the functional P450 holoenzyme. The W126R variant was not expressed in E. coli. Binding affinities of lauric acid in K276T and S353G variants were stronger than that of wild type. Steady-state kinetics in the hydroxylation reaction of fatty acids were studied. The catalytic efficiencies (k<SUB>cat</SUB>/K<SUB>m</SUB>) of K276T and S353G variants in the reactions without cytochrome b<SUB>5</SUB> were approximately 2- and 4-fold higher, respectively, than that of wild type, and in the reactions with cytochrome b<SUB>5</SUB> they were approximately 2- and 3-fold higher, respectively. These results suggest that individuals carrying the alleles, K276T and S353G, might exhibit higher catalysis of CYP4A11, which may affect the endogenous metabolic products associated with regulation of blood pressure.

Purification and characterization of a novel fibrinolytic α chymotrypsin like serine metalloprotease from the edible mushroom, Lyophyllum shimeji

Moon, S.M.,Kim, J.S.,Kim, H.J.,Choi, M.S.,Park, B.R.,Kim, S.G.,Ahn, H.,Chun, H.S.,Shin, Y.K.,Kim, J.J.,Kim, D.K.,Lee, S.Y.,Seo, Y.W.,Kim, Y.H.,Kim, C.S. Society for Bioscience and Bioengineering, Japan ; 2014 Journal of bioscience and bioengineering Vol.117 No.5

A novel fibrinolytic enzyme was purified from Lyophyllum shimeji, a popular edible mushroom in Asia. The enzyme was purified using combination of anion exchange chromatography on a Mono Q 5/5 column and size exclusion gel filtration chromatography on Superdex 200 100/300 column. This purification protocol resulted 80.9-fold purification of the enzyme and a final yield of 5.7%. The molecular weight of the purified enzyme was estimated to be 21 kDa by SDS-PAGE and size exclusion gel filtration. The N-terminal amino acid sequence was found to be ITFQSASP, which is dissimilar from that of known fibrinolytic enzymes. The purified enzyme was a neutral protease with an optimal reaction pH and temperature of 8.0 and 37<SUP>o</SUP>C, respectively. Enzymatic activity was inhibited by Cu<SUP>2+</SUP> and Co<SUP>2+</SUP>. It was also significantly inhibited by PMSF and TPCK. Furthermore, it was found to exhibit a higher specificity for S-7388, a well-known chymotrypsin chromogenic substrate, indicating chymotrypsin like serine metalloprotease. The relative fibrinolytic activity of 5 μg purified enzyme have two fold more activity than 1 unit/ml of plasmin on fibrin plate. Furthermore, purified enzyme preferentially hydrolyzed the Aα-chain followed by the Bβ- and γ-chain of fibrinogen, which is precursor of fibrin. Therefore, these data suggests that the fibrinolytic enzyme derived from edible mushroom, L. shimeji, might be useful for thrombolytic therapy and preventing thrombotic disease.

A Case of Maffucci's Syndrome Associated with Spindle-cell Hemangioendothelioma

Lee, K. S Korean Dermatological Association 1998 Annals of Dermatology Vol.10 No.3

육군에 있어서 정신치료의 소지 (素地)

전등부,김현수,서찬수 大韓神經精神醫學會 1970 신경정신의학 Vol.9 No.1

지금까지 육군에 있어서 군의환경과 정신과 환자, 정신과 군의관의 입장을 개관하고 치료의 부정적요소를 살펴보았다. 환자가 가진 문제의 범위, 동기의 결핍과, 저항, 치료기간의 제한, 군의관의 치료적능력과 환자- 군의관관계의 치료적 가능성을 고찰하고 군의관 자신의 여러모양의 노력으로 극복의 여지가 있으며 단기치료의 적용성을 더욱 시도해야할 필요성을 느꼈다. Some implications of psychotherapy and Antitherapeutic factors in the Korean Army Service has been discussed, briefly considering category of patient's problems, resistance and lack of motivation, limitation of the length of treatment, and patient-therapist relationships and it's therapeutic potentials. The author noted the space to overcome these week-sides by therapist's personal training and suggested application of short-term psychotherapy.

Highly selective iron-based Fischer-Tropsch catalysts activated by CO₂-containing syngas

Chun, D.H.,Park, J.C.,Hong, S.Y.,Lim, J.T.,Kim, C.S.,Lee, H.T.,Yang, J.I.,Hong, S.,Jung, H. Academic Press 2014 Journal of catalysis Vol.317 No.-

Fischer-Tropsch synthesis (FTS) was carried out over precipitated iron-based catalysts activated by syngas (H<SUB>2</SUB>+CO) with different amounts of CO<SUB>2</SUB> (0%, 20%, 33%, and 50%). The activation using CO<SUB>2</SUB>-containing syngas significantly suppressed the production of undesired products, CH<SUB>4</SUB> and C<SUB>2</SUB>-C<SUB>4</SUB> hydrocarbons, but facilitated the production of valuable products, C<SUB>5+</SUB> hydrocarbons. In particular, in the case of C<SUB>19+</SUB> hydrocarbons, the target products of low-temperature FTS (≤280<SUP>o</SUP>C), both selectivity and productivity showed a great increase with an increased inlet CO<SUB>2</SUB> content during activation. We attribute the advantageous performance of the catalysts activated by CO<SUB>2</SUB>-containing syngas to the improvement in the effective performance of active iron carbides, possibly induced by an increased ratio of ε'-carbide (Fe<SUB>2.2</SUB>C) to χ-carbide (Fe<SUB>2.5</SUB>C) and a decreased fraction of inactive bulk carbons.