A Computational Investigation of the Stability of Cyclopropyl Carbenes

Baik, Woon-Phil,Yoon, Cheol-Hun,Koo, Sang-Ho,Kim, Byeong-Hyo Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.1

The conformations of dicyclopropyl, isopropyl cyclopropyl, and diisopropylcarbenes were optimized using density functional theory (B3LYP/6-31G(d)). We showed that the optimized geometries of carbenes with cyclopropyl groups are fully in accord with those expected for bisected W-shaped conformations, in which the effective hyperconjugation of a cyclopropyl group with singlet carbene can occur. The stabilization energies were evaluated at the B3LYP/6-311+G(3df, 2p)//B3LYP/6-31G(d) + ZPE level using an isodesmic equation. The relative stability of carbenes is in the order $(c-Pr)_2$C: > (i-Pr)(c-Pr)C: > $(i-Pr)_2$C:, and a cyclopropyl group stabilizes carbene more than an isopropyl group by nearly 9 kcal/mol. Energies for the decomposition of diazo compounds to carbenes increase in the order $(c-Pr)_2$ < (i-Pr)(c-Pr) < $(i-Pr)_2$ by ~9 kcal/mol each. From a singlettriplet energy gap ($E_{ST}$) calculation, the singlet level is lower than the triplet level and the $E_{ST}$ shows a trend similar to the stabilization energy calculations. For comparison, the optimized geometries and stabilization energies for the corresponding carbocations were also studied at the same level of calculation. The greater changes in geometries and the higher stabilization energies for carbocations compared to carbenes can explain the greater hyperconjugation effect.

Lewis Acid-Catalyzed Reactions of Anthrone: Preference for Cycloaddition Reaction over Conjugate Addition Depending on the Functionality of α,β-Unsaturated Carbonyl Compounds

Baik, Woon-Phil,Yoon, Cheol-Hoon,Koo, Sang-Ho,Kim, Ha-Kwon,Kim, Ji-Han,Kim, Jeong-Ryul,Hong, Soo-Dong Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.4

The Lewis acid-catalyzed reactions of anthrone with a variety of ethylenic substrates under various conditions have been studied. It has been observed that depending on kinds of ethylenic substrates and catalysts, products were varied. In particular, the $ZnCl_2$-catalyzed reaction of anthrone with ${\alpha},{\beta}$ -unsaturated ester gave bridged compounds 3 (Diels-Alder adduct type) and mono-Michael adduct 4 exclusively, while the base-catalyzed reaction gave 10,10-bis-Michael adduct as a major product independent of the amount of ethylenic substrate and base. Bridged compounds 3 were easily converted to the corresponding mono-Michael adduct 4 by a catalytic amount of base. Further Michael reaction of mono-Michael adducts with different ethylenic substrates in the presence of a catalytic amount of alkoxide gave unsymmetrical 10,10-bis Michael adducts in good or moderate yields.

The Urine Organic Acid Profile Can Be a Good Biomarker for the Traditional Korean Diet Study

Phil-Kyung Shin,Myung Sunny Kim,Hae-Jeung Lee,Seon-Joo Park,Dae Young Kwon,Sang-Woon Choi 한국식품영양과학회 2017 한국식품영양과학회 학술대회발표집 Vol.2016 No.10

Therapeutic Potential of Adipose Tissue-Derived Stem Cells in Acute Lung Injury Rat Model

( Woon Jeong Lee ),( Yeon Hee Jung ),( Si Kyung Jung ),( Melissa K. Middleton ),( Seung Phil Choi ),( Gyu Nam Park ) 한국조직공학·재생의학회 2011 조직공학과 재생의학 Vol.8 No.1

Acute respiratory distress syndrome (ARDS) is a major cause of morbidity and mortality in critically ill patients. We evaluated the therapeutic potential of adipose tissue-derived stem cells (ATSCs) in a murine model of acute lung injury (ALI). ATSCs, labeled with PKH-26, were injected intravenously into rats 24 hours after intratracheal lipopolysaccharide (LPS) challenge. Two or 14 days later, the rats were sacrificed to assess cell migration to injured lung and the degree of lung injury. ATSCs were identified both in ALI lung and in normal lung at 2 d after cell transplantation. However, after 14 d, more ATSCs were found in the ALI lung than in the normal lung. Furthermore, ATSC-treated rats demonstrated a trend towards decreased lung inflammation as measured by BAL cytokines and cellular response. These data suggest that intravenously injected ATSCs can migrate to acutely injured lung and may potentially play a role in attenuating the inflammatory response.

Walnut phenolic extracts reduce telomere length and telomerase activity in a colon cancer stem cell model

Phil-Kyung Shin,Yoonchae Zoh,Jina Choi,Myung-Sunny Kim,Yuri Kim,Sang-Woon Choi 한국영양학회 2019 Nutrition Research and Practice Vol.13 No.1

BACKGROUND/OBJECTIVES: Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS AND METHODS: CD133<SUP>+</SUP>CD44<SUP>+</SUP> cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and 40 μg/mL for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA (ddCt). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA (dCt). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS: Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner (5.16 ± 0.13 at 0 μg/mL, 4.79 ± 0.12 at 10 μg/mL, 3.24 ± 0.08 at 20 μg/mL and 3.99 ± 0.09 at 40 μg/mL; P = 0.0276). Telomerase activities concurrently decreased with telomere length (1.47 ± 0.04, 1.09 ± 0.01, 0.76 ± 0.08, and 0.88 ± 0.06; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSION: In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.

Estimating the Mixture of Proportional Hazards Model with the Constant Baseline Hazards Function

Jong-woon Kim,Seong-phil Eo 한국신뢰성학회 2005 한국신뢰성학회 학술대회논문집 Vol.2005 No.6

한식의 체내 대사에 미치는 영향에 대한 연구: 소변 유기산 분석을 통한 한식의 효과

신필경(Phil-Kyung Shin),천수경(Sukyung Chun),김명선(Myung Sunny Kim),박선주(Seon-Joo Park),김민정(Min Jung Kim),권대영(Dae Young Kwon),김경철(KyongChol Kim),이해정(Hae-Jeung Lee),최상운(Sang-Woon Choi) 한국영양학회 2020 Journal of Nutrition and Health Vol.53 No.3

소변은 쉽게 채취할 수 있으며 체내의 상태를 파악하기에 좋은 시료라고 할 수 있다. 본 연구에서는 2주간의 한식 섭취 후 변화된 소변 유기산 지표를 찾을 수 있었다. 그 결과 에너지 대사와 관련 있는 대사산물인 succinate, hydroxymethylglutarates 뿐만 아니라 tryptophan 대사물로써 신경전달 물질대사 지표인 5-hydroxyindoleacetate, 비타민 B6, 염증, 면역과도 관련이 있는 kynurenate, 장내세균과 관련 있는 indican이 한식의 섭취를 통해 유의한 차이로 변화하는 것을 확인하여 한식의 효능이 어떤 대사를 통하여 이루어 지는지의 방향 제시를 하였다. 또한 소변 유기산이 한식의 대사에 미치는 영향을 측정하는 생체지표로서의 활용 가능성도 보여주었다. 객관적인 지표로서 확증하기 위해 더욱 큰 표본에서의 연구, 성별, 질병별 다양화한 연구를 통해 관찰된 지표들의 재현성을 확인하여 생체 지표로서의 유효성 검증이 필요하겠다. Purpose: To determine the metabolic influence of the traditional Korean diet (K-diet), which has been regarded as a healthy diet, we investigated the profile of urine organic acids that are intermediates of various types of metabolism including energy metabolism. Methods: Ten women aged 50–60 years were recruited and randomly divided into 2 diet groups, K-diet and control diet, the latter of which is a Westernized Korean diet that is commonly consumed by Koreans nowadays. Before and after the 2-week intervention, 46 urine organic acids were determined using LC/MS/MS, along with clinical parameters. Results: The average concentrations of succinate (4.14 ± 0.84 μg/mg creatinine vs. 1.49 ± 0.11, p = 0.0346) and hydroxymethylglutarate (3.67 ± 0.36 μg/mg creatinine vs. 2.97 ± 0.29, p = 0.0466), both of which are intermediates of energy metabolism, decreased in the K-diet group after the 2-week intervention, but these were not observed in the control diet group. In particular, the average concentration of succinate in the K-diet group was lower than that in the control group (3.33 ± 0.56 μg/mg creatinine vs. 1.49 ± 0.11, p = 0.0284) after 2 weeks. The concentrations of two tryptophan metabolites, 5-hydroxyindolacetate (3.72 ± 0.22 μg/mg creatinine vs. 3.14 ± 0.21, p = 0.0183) and indican (76.99 ± 8.35 μg/mg creatinine vs. 37.89 ± 10.06, p = 0.0205) also decreased only in the K-diet group. After the 2-week intervention, the concentration of kynurenate, another tryptophan metabolite, was lower in the K-diet group than that in the control diet group (3.96 ± 0.51 μg/mg creatinine vs. 2.90 ± 0.22, p = 0.0356). Interestingly, the urine level of kynurenate was positively correlated with BMI (r = 0.61424, p = 0.0003) and total cholesterol (r = 0.46979, p = 0.0088), which decreased only in the K-diet group (239.40 ± 15.14 mg/dL vs. 198.20 ± 13.25, p = 0.0163). Conclusion: The K-diet alters the urinary excretion of organic acids involved in energy metabolism and tryptophan metabolism, suggesting the influence of the K-diet on these types of metabolism. Urine organic acids changed by the K-diet may serve as biomarkers in future studies.

Modulation of theta phase synchronization in the human electroencephalogram during a recognition memory task

Kim, Sung-Phil,Kang, Jae-Hwan,Choe, Seong-Hyun,Jeong, Ji Woon,Kim, Hyun Taek,Yun, Kyongsik,Jeong, Jaeseung,Lee, Seung-Hwan Lippincott Williams Wilkins, Inc. 2012 NEUROREPORT - Vol.23 No.11

To the extent that recognition memory relies on interactions among widely distributed neural assemblies across the brain, phase synchronization between brain rhythms may play an important role in meditating those interactions. As the theta rhythm is known to modulate in power during the recognition memory process, we aimed to determine how the phase synchronization of the theta rhythms across the brain changes with recognition memory. Fourteen human participants performed a visual object recognition task in a virtual reality environment. Electroencephalograms were recorded from the scalp of the participants while they either recognized objects that had been presented previously or identified new objects. From the electroencephalogram recordings, we analyzed the phase-locking value of the theta rhythms, which indicates the degree of phase synchronization. We found that the overall phase-locking value recorded during the recognition of previously viewed objects was greater than that recorded during the identification of new objects. Specifically, the theta rhythms became strongly synchronized between the frontal and the left parietal areas during the recognition of previously viewed objects. These results suggest that the recognition memory process may involve an interaction between the frontal and the left parietal cortical regions mediated by theta phase synchronization.

개인 디지털 데이터의 Seamless 한 전달을 위한 3S (Sync/shift/storage) 플랫폼 개발

허성필(Sung-Phil Heo),홍완표(Wanpyo Hong),송유진(Yujin Song),이고운(Go Woon Lee),민동순(Dong-Soon Min),이미숙(Mi-Sook Lee),전윤철(Yun-Chul Jun) 한국통신학회 2008 한국통신학회 학술대회논문집 Vol.2008 No.7

감마선 조사에 의해 제조된 키토산/아크릴산 하이드로겔의 특성

심재운 ( Jae Woon Shim ),강필현 ( Phil Hyun Kang ),박성은 ( Sung Eon Park ),노영창 ( Young Chang Nho ) 한국공업화학회 2002 공업화학 Vol.13 No.7

키토산(chitosan)을 아크릴산에 용해시킨 후 개시제 혹은 가교제를 필요로 하지 않는 감마선을 이용해 약물 전달용 하이드로겔을 제조하고 그 특성을 조사하였다. 키토산과 아크릴산의 조성비를 각각 0.1∼1.5 wt%와 30, 50, 70 vol%로 혼합하여 30∼70 KGy의 조사량으로 감마선 조사하여 제조된 하이드로겔의 겔함량은 96% 이상이었으며, 키토산과 아크릴산의 비율이 증가할수록, 조사량이 증가할수록 99%까지 증가하였다. 제조된 겔의 팽윤도는 키토산과 아크릴산의 비율이 증가할수록, 조사량이 증가할수록 감소하였으며, 20 h 내에서 급격히 증가하다가 서서히 평형에 도달하였다. 또한, 감마선 조사로 제조된 chitosan/AAc 겔을 pH 1∼12에서 팽윤시킨 결과, 용액의 pH가 증가 할수록 팽윤도도 증가하였으며, pH 12에서 가장 큰 값을 나타내었다. 이러한 겔의 팽윤 특성은 감마선 조사에 의해 형성된 가교결합과 이온화된 amino기와 carboxyl기의 작용에 의한 것임을 FT-IR과 SEM 관찰로 확인할 수 있었다. The chitosan/acrylic acid (AAc) hydrogels for drug delivery were synthesized with polymerization of acrylic acid in the presence of chitosan mitiated by gamma-ray irradiation and their characteristics were investigated. Various chitosan/AAc hydrogels were prepared with the different ratios of chitosan (0.1∼1.5 wt%), acrylic acid (30, 50, 70 vol%) and radiation dose (30∼70 KGy). The gel contents of hydrogels were more than 96%, and as the ratios of chitosan/acrylic acid and radiation dose were increased, it increased to 99%. The swelling degrees of chitosan/AAc hydrogels decreased as the ratio of chitosan/acrylic acid and radiation dose increased, and reached equilibrium within 20 h. In the pH range of 1∼12, chitosan/AAc hydrogels were more swollen at high pH than low pH, and showed the largest swelling occurred at pH 12. FTIR as well as SEM results indicated that the swelling characteristics of chitosan/AAc hydrogels were due to the cross-linking of ionized amino and carboxylic functional groups by gamma irradiation.