Lignans from the Flower Buds of Magnolia fargesii

박기훈,Min Suk Yang,Sang Hae Nam,Mi Yae Shon,Seon Woo Hwang,Jun Lee 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.6

The three new lignans 1-3 were isolated from the methanol extracts of the flower buds of Magnolia fargesii. They were elucidated as (7S,8R)-1-(3,4-dimethoxyphenyl)-2-O-(2-methoxy-4-omegahydroxypropylphenyl) propane-1,3-diol, (7S,8S)-1-(4-hydroxy-3-methoxyphenyl)-2-O-(6-hydroxy-2-methoxy-4-omegahydroxy- propylphenyl) propane-1,3-diol, and [tetrahydro-4-hydroxy-2-(3,4,5-trimethoxyphenyl)furan-3-yl]methyl 3,4-dimethoxy benzoate by spectral analysis.

Ethanol and Water Extract of Purple Sweet Potato Exhibits Anti-Atherosclerotic Activity and Inhibits Protein Glycation

박기훈,김재룡,이준설,Hwahyung Lee,조경현 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.1

It is well known that extracts of purple sweet potato (PSP) have potent antioxidant activity. However, it has not been established whether extracts of PSP inhibit oxidation of low-denstiy lipoprotein (LDL) or protein glycation. LDL oxidation and protein glycation are well-known risk factors for chronic metabolic diseases, such as atherosclerosis and diabetes mellitus. Chopped and sliced PSP and yellow sweet potato (YSP) were extracted individually at a concentration of 1g of PSP tuber/mL using either ethanol or water for 6 hours. The PSP ethanol extract (100-fold diluted) showed stronger radical (2,2-diphenyl-1-picrylhydrazyl radical) scavenging activity than the water extract of PSP and the ethanol extract of YSP (up to a sixfold higher activity). The ethanol extract of PSP also exhibited the highest increase in ferric reducing ability among all extracts. Cupric ion-mediated LDL oxidation was strongly inhibited by the ethanol extract of PSP, with similar potency to vitamin C treatment (final concentration, 10mM). The PSP extract strongly inhibited fructose-mediated protein glycation as determined by fluorescence spectroscopy. The PSP extract-treated apolipoprotein (apo) A-I showed a decreased multimerization pattern on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas glycated apoA-I showed the strongest multimeric band. PSP extract treatment also inhibited the uptake of oxidized LDL into human macrophage cells with suppression of malondialdehyde production in the cell culture medium. In conclusion, these results suggest that the extract of PSP can be used as a putative anti-atherosclerotic and antidiabetic agent with strong antioxidant functions. This is the first report to show the biological functions of PSP extract to treat hyperlipidemic and hyperglycemic disorders.

Case of Monoclonal Pulmonary MALT Lymphoma Arising in a Polyclonal Lymphoproliferative Disorder

박기훈,권순석,김용현 대한결핵 및 호흡기학회 2011 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.112 No.-

고리형 아민이 포함된 메탄 하이드레이트의 튜닝과 가스 저장 연구

박기훈,김동현,차민준,Ki Hun Park,Dong Hyun Kim,Minjun Cha 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.3

In this study, the tuning phenomena, gas storage capacity, and thermal expansion behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were investigated for the potential applications of clathrate hydrates to gas storage. To understand the tuning behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates, ¹³C solid-state NMR spectroscopy was used, and the results confirmed that maximum tuning factors for the binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were achieved at 0.5 mol% and 1.0 mol% of guest concentration, respectively. The gas storage capacity of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were also checked, and the results showed the CH₄ capacity of our hydrate systems was superior to that of binary (tetrahydrofuran + CH₄) and (cyclopentane + CH₄) clathrate hydrates. The synchrotron diffraction patterns of these hydrates collected at 100, 150, 200, and 250 K confirmed the formation of a cubic Fd-3m hydrate. In addition, the lattice constant of clathrate hydrates with cyclopentylamine and methane were larger than that with cyclopropylamine and methane due to the effects of molecular size and shape.

마크업 언어를 이용한 고객 요구사항 분석

박기훈,조용민,황미희 대한산업공학회 2009 대한산업공학회 추계학술대회논문집 Vol.2009 No.10

지능 작동기를 이용한 조종익 구동연구

박기훈,윤범수,윤광준,이상기,우기영 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

NON-GREY RADIATIVE TRANSFER IN THE PHOTOSPHERIC CONVECTION : THE VALIDITY OF THE EDDINGTON APPROXIMATION

박기훈 한국천문학회 2016 Journal of The Korean Astronomical Society Vol.49 No.1

The aim of this study is to describe the physical processes taking place in the solar photosphere. Based on 3D hydrodynamic simulations including a detailed radiation transfer scheme, we investigate thermodynamic structures and radiation fields in solar surface convection. As a starting model, the initial stratification in the outer envelope calculated using the solar calibrations in the context of the standard stellar theory. When the numerical fluid becomes thermally relaxed, the thermodynamic structure of the steady-state turbulent flow was explicitly collected. Particularly, a non-grey radiative transfer incorporating the opacity distribution function was considered in our calculations. In addition, we evaluate the classical approximations that are usually adopted in the one-dimensional stellar structure models. We numerically reconfirm that radiation fields are well represented by the asymptotic characteristics of the Eddington approximation (the diffusion limit and the streaming limit). However, this classical approximation underestimates radiation energy in the shallow layers near the surface, which implies that a reliable treatment of the non-grey line opacities is crucial for the accurate description of the photospheric convection phenomenon.

일본 실버인재센터의 노인교육체계 일고찰

박기훈 한국노년교육학회 2019 한국노년교육학회 학술대회 발표집 Vol.2019 No.2

Comparison of Clinical Characteristic and Survival for Pulmonary Large Cell Neuroendocrine Carcinoma and Small Cell Lung Cancer (초)

박기훈,송정섭,윤형규 대한결핵 및 호흡기학회 2010 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.110 No.-

EVOLUTIONARY STATUS AND INTERNAL STRUCTURE OF μ CASSIOPEIAE

박기훈 한국천문학회 2015 Journal of The Korean Astronomical Society Vol.48 No.3

We investigate physical properties of the nearby ($\sim$ 7.5 \pc) astrometric binary $\mu$ Cas in the context of standard evolutionary theory. Based on the spectroscopically determined relative abundances ($\AlphaoverFe$ $\gtrsim +0.4 \,\dex$, $\FeoverH \sim -0.7 \,\dex$), all physical inputs such as opacities and equation of state are consistently generated. By combining recent spectroscopic analyses with the astrometric observations from the \emph{HIPPARCOS} parallaxes and the \emph{CHARA} array, the evolutionary model grids have been constructed. Through the statistical evaluation of the $\chi^2$-minimization among alternative models, we find a reliable evolutionary solution ($M_A$, $M_B$, $t_{age}$) = (0.74 \Msun, 0.19 \Msun, 11 \Gyr) which excellently satisfies observational constraints. In particular, we find that the helium abundance of $\mu$ Cas is comparable with the primordial helium contents ($Y_p \sim 0.245$). On the basis of the well-defined stellar parameters of the primary star, the internal structure and the $p$-mode frequencies have been estimated. From our seismic computation, $\mu$ Cas is expected to have a first order spacing $\Delta\nu \sim 169 \,\muHz$. The ultimate goal of this study is to describe physical processes inside a low-mass star through a complete modelling from the spectroscopic observation to the evolutionary computation.