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추황배(Pyrus pyrifolia Nakai cv. Chuhwangbae) 과피로부터 1종의 Sterol과 3종의 배당체 화합물의 단리·동정
이유건(Yu Geon Lee1),조정용(Jeong-Yong Cho),이현주(Hyun Joo Lee),이용현(Yong Hyun Lee),이상현(Sang-Hyun Lee),한태호(Tae-Ho Han),김월수(Wol-Soo Kim),박근형(Keun-Hyung Park),문제학(Jae-Hak Moon) 한국식품과학회 2013 한국식품과학회지 Vol.45 No.5
본 연구에서는 배의 유용성 증명을 위한 일환으로 배의 화학성분을 분자수준에서 밝히고자 하였다. 이에 배 과피 MeOH 추출물을 용매분획하여 얻은 EtOAc-산성 분획과 EtOAc-중성분획을 대상으로 Sephadex LH-20, silica gel, 그리고 ODS colmn chromatography와 HPLC를 이용하여 정제 및 단리하였다. 그 결과, EtOAc-산성 분획과 EtOAc-중성 분획으로부터 각각 2종씩의 화합물을 단리하였다. 단리된 화합물 1-4는 1H- 및 13C-NMR 분석을 통하여 각각 (S)-(+)-2-cis-abscisic acid O-β-D-glucopyranosyl ester (화합물 1), 1-[4-O-β-D-glucopyranosyl]phenyl ethanone(piceoside, 화합물 2), β-sitosterol (화합물 3), 그리고 β-sitosteryl 3-O-β-D-glucopyranoside (화합물 4)로 동정되었다. 단리된 3종의 배당체 화합물(화합물 1, 2, 4)들은 본 연구에 의해 배로부터 처음 동정되었으며, 화합물 3은 추황배로부터 처음 동정되었다. 본 연구결과가 배 함유 성분연구는 물론 배의 기능성 해명 연구에도 추후 중요한 기초자료로 활용되길 기대한다. We isolated and identified antioxidants from acidic and neutral ethyl acetate fractions of the peel of pear (Pyrus pyrifolia N. cv. Chuhwangbae). We isolated 4 compounds from the methanol extract, by using 3 different types of column chromatography (Sephadex LH-20, silica gel, and octadecylsilane) and preparative HPLC. We identified the isolated compounds as (S)-(+)-2-cis-abscisic acid O-β-D-glucopyranosyl ester (compound 1), 1-[4-O-β-D-glucopyranosyl]phenyl ethanone (picroside, compound 2), β-sitosterol (compound 3), and β-sitosteryl 3-O-β-D-glucopyranoside (compound 4) by nuclear magnetic resonance analysis. We are the first to report the identification of compounds 1, 2, and 4 from pear.
이병구,황학주,이원복 연세대학교 산업기술연구소 1975 논문집 Vol.6 No.1
Numerical data have been presented for the natural frequencies and modes of vibration of fixed, uniform, circular arches vibrating in their own plane, and the effects of the rotatory inertia and shear deformation affecting the response have been analyzed. The governning differential equations were solved numerically by a combination of a Holzer-type iterative procedure and an initial value integration procedure. The Runge-Kutta fifth order integration technique was used. The method was programmed for a Cyber 73-18 computer system, and all results were obtained on this computer system. A detailed study has been made of the lowest five vibration frequencies and mode shapes for a fixed arch with an angle of opening equal to 90 degrees. The effect of slenderness ratio and the influence of the rotatory inertia and shear deformation on frequencies are presented in detail in curves.
항고형암제의 활성평가를 위한 in vitro 삼차원 암세포 배양계의 확립
이상학,이주호,구효정 한국약제학회 2004 Journal of Pharmaceutical Investigation Vol.34 No.5
For the efficient determination of activity against solid tumors, an in vitro tumor model that resembles the condition of in vivo solid tumors, is required. The purpose of this study was to establish a rapid culture method and viability assay for an in vitro 3-dimensional tumor model, multicellular spheroid (MCS). Among 12 human cancer cell lines, a few cell lines including DUD-1 (human colorectal carcinoma cells) formed fully compact MCS which was adequate for in vitro viability assay. DLD-1 MCS showed steady growth reaching 700 pm diameter after 11 day culture. DUD-1 cells grown as MCS showed significant increase in G_(0)/G₁ phase compared to the monolayer cells (73.9% vs 45.7%). but necrotic regions or apoptotic cells were not observed. The cells cultured as MCS showed resistance to 5-FU (10.3 fold higher IC_(50)) compared to monolayers. however, tirapazamine (a hypotoxin) showed similar activity in both culture systems. In summary, MCS may be a valid in vitro model for activity screening of anticancer agents against human solid tumors and also exploitable for studying molecular markers of drug resistance in human solid tumors.
이주형,이봉학,홍창우,김동호 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-
Cracking is considered to be one of the important factors in determining the durability of reinforced concrete structures. When the bending stress exceeds the modulus of rupture of the concrete, cracking fom along the length of members. The total load is transferred across these cracks by the reinforcement, but the concrete between craks is still capable of carrying stresses due to the bond between steel and concrete. This phenomenon is called the tension stifening effect. The tension stiffening effect is affected by many variables, such as the bond stress, strength of concrete, interrocking of aggregate, type of steel, and dowel action of steel. Also, this tension stifening effect is usually quite significant in beams under service loading, and must be taken into account in the calculation of deflection and crack widths. In this study, the experiment was carried out on types of specimen, strength of concrete, and steel ratio and finite element analysis were compared in terms of load-deflection relationship, crack pattern.
소포제 종류 및 혼입률에 따른 초속경 라텍스개질 모르타르의 역학적 특성
이봉학,홍창우,이주형,김동호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B
The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types (A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.
유한요소해석을 이용한 현장 덧씌우기 콘크리트의 부착강도 평가 방법 제안
이봉학,홍창우,이주형,김성환 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B
Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction defends upon band strength between old and the new concrete. Current adhesion strength measurement method is inaccurate method that ignore effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5cm. Elastic modulus and overlay thickness do not influence in stress concentration.
시멘트 종류에 따른 SB 라텍스 개질 콘크리트의 강도 및 투수특성
이봉학,홍창우,이주형,김동호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B
This study focused on the investigation of strength development and permeability of LMC(Latex Modified Concrete) and RSLM(Rapid-Setting Cement Latex Modified Concrete) as the latex content cement types and s/c ratio changed. The compressive strength of latex modified concrete decreased slightly and the flexural strength increased quitely at 15% of latex content. This may be due to the flexibility of latex filled in voids and interconnections of hydrated cement and aggregates by a film of latex particles, respectively. The permeability test results showed that the permeability of LMC was considerably lower than that of conventional concrete. Results of chloride permeability test, for RSLMC indicated very low at an early age caused by the early formation of needle-shape ettringites and latex film.