• 생약학회지
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• 제17권2호
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• pp.168-177
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• 1986

Bioassay-directed isolation has yielded some cytotoxic substances against L1210 cell from the Korean traditional medicine. These include 5,2'-dihydroxy-6,7,8,6'-teramethoxyflavone $(IV,\;scutellaria\;root,\;ED_{50}\;=\;1.7\;{mu}g/ml)$, 7-geranyloxycoumarin $(XXXII,\;poncirus\;fruit,\;10.2\;{mu}g/ml) $and panaxydol $(I,\;white\;ginseng,\;0.03\;{mu}g/ml)$. IV, XXXII and their derivatives were synthesized in the purpose of in vivo tests and for observation of structure-activity relations. Among the flavone derivatives, 5,2',6'-trihydroxy-6,7,8-trimethoxy flavone (XVIII), 5-hydroxy-6,7,8-trimethoxy-6'-benzyloxyflavone (XVII) and 5,8-dihydroxy-6,7-dimethoxyflavone (X) showed the cytotoxicity which has no correlation to the flavone structures. Of the coumarins synthesized, 7,8-dihydroxycoumarin (XXVI), 6-7-dihydroxycoumarin (XXIX) and 6-hydroxy-5,7-dimethoxycoumarin (XXXI) showed considerable activities. Acetylated XXXI has moderate activity $(ED_{50}=17.2\;{mu}g/ml)$. Monobydroxycoumarins or their methyl and allyl ether were inactive. IV inhibits the growth of the solid form of S-180 by 70% at 40 mg/kg and shows T/C of 166% on the ascitic S-180 at 40 mg/kg. It strongly inhibits the activity of the membrane bounded ATPase from L1210 cell. The most cytotoxic fraction of the antitumor materials studied is the one from the trichosanthes root showing $ED_{50}=0. 0003\;{mu}g/ml$ against L1210 cell. This fraction, obtained from ethyl acetate extract, showed T/C of 130 and 135%, on ICR mice bearing S-180 and $BDF_1$ mice bearing L1210 at 10 mg/kg and 7.5 mg/kg, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.282-284
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• 1997

Ultrasonic motors using piezoelectric ceramics and brass metal endcaps were fabricated, which is operated by single - phase high frequency. The structure of the ultrasonic motors has the wind-mill type. The stator part consists of a piezoelectric disk and two metal endcaps slotted wind-mill type. According to the piezoceramic disk vibrates as a radial mode, two metal endcaps provide both longitudinal and torsional displacements simultaneously. Because the metal endcaps have a nonsymmetric structure. the principle of the ultrasonic motor is not well understood. The dimension of the ultrasonic motor is diameter in 12.7 mm and thickness in 2.0 mm, and especially the PMN-PT-PZ piezoelectric disk was used. The maximum revolution speed 700 rpm and the maximum torque 0.22 mN.m were obtained. The ultrasonic motor for rotation was Supplied only single phase AC.

• 대한화학회지
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• 제42권4호
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• pp.378-382
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• 1998

Phenylcyclohexylamine과 dexoxadrol에 대한 정량적 구조-작용 상관관계에 관한 계산을 반경험적 분자궤도법인 PM3와 Hyper Chem 프로그램을 이용하여 수행하였다. 19개의 PCA 유도체들의 프론티어 오비탈 크기와 LogP 값은 운동에 영향을 미치는 독성과 MES 발작 실험에서 $MES\;ED_{50}$과 $TD_{50}$을 예측하는 좋은 매개 변수라는 사실을 알았다.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.380.2-380.2
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• 2002

Peroxisome proliferator-activated receptor (PPAR)-$\gamma$ is a nuclear hormone receptor family that plays an important role in the transcriptional regulation of genes in cellular lipid and energy metabolism. In our search for Iigands for PPAR-$\gamma$ from natural resources. two phenylpropanoids. 3.4.5-Trimethoxy cinnamylalcohol (1) and 3.4.5- Trimethoxy cinnamaldehyde (2). were isolated as PPAR-$\gamma$ agonists from the MeOH extracts of Zanthoxylum schinifolium Sieb. & ZUCCo (Rutaceae) by activity-guided fractionation. These two compoundS bind and activated PPAR-$\gamma$ transcriptional activity in a dose dependent manner assessed by ligand-binding assay. While the maximum activities for PPAR-$\gamma$ of these compounds were comparable with that of rosiglitazone. which is currently used in the treatment of Type II diabetes. the potency of these compounds were much weaker than rosiglitazone ($ED_{50}$=t.2$\mu\textrm{M}$) with the $ED_{50}$ values of 9.08 and 4.08 $\mu\textrm{M}$. respectively. To examine the structure-activity relationship of phenylpropanoids. we prepared several phenylpropanoid derivatives and measured the activity. We observed that substituents at 4'- position could playa key role in determining the potency for PPAR-$\gamma$ agonistic activity .

• 국제초고층학회논문집
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• 제3권1호
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• pp.21-33
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• 2014

The tied braced frame (TBF) system was developed to achieve uniform seismic inelastic demand along the height of multi-storey eccentrically braced steel frames. A modular tied braced frame (M-TBF) configuration has been recently proposed to reach the same objective while reducing the large axial force demand imposed on the vertical tie members connecting the link beams together in TBFs. M-TBFs may however experience variations in storey drifts at levels where the ties have been removed to form the modules. In this paper, the possibility of reducing the discontinuity in displacement response of a 16-storey M-TBF structure by introducing energy dissipating (ED) devices between the modules is examined. Two M-TBF configurations are investigated: an M-TBF with two 8-storey modules and an M-TBF with four 4-storey modules. Three types of ED devices are studied: friction dampers (FD), buckling restrained bracing (BRB) members and self-centering energy dissipative (SCED) members. The ED devices were sized such that no additional force demand was imposed on the discontinuous tie members. Nonlinear response history analysis showed that all three ED systems can be used to reduce discontinuities in storey drifts of M-TBFs. The BRB members experienced the smallest peak deformations whereas minimum residual deformations were obtained with the SCED devices.

• 약학회지
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• 제42권2호
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• pp.159-164
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• 1998

The secondary hydroxy group at side chain of shikonin structure was selectively acylated with various haloacetic acids in presence of dicyclohexylcarbodiimide and 4-dimethylamin opyridine to produce haloacetylshikonin derivatives. The cytotoxicity of monohaloacetylshikonin derivatives against L1210 cells increased in the following order; monochloroacetylshikonin ($ED_{50}$, 0.142${\mu}$g/ml) > monobromoacetylshikonin ($ED_{50}$. 0.158${\mu}$g/ml) > monoiodoacetylshikonin ($ED_{50}$, 0.173${\mu}$g/ml). Introduction of larger halogen atoms decreased the cytotoxic activity, presumably due to steric hinderance. The cytotoxicity of chloroacetylshikonin derivatives was dependent on the number of chlorine atom, thus increasing in the following order; trichloroacetylshikonin (0.032${\mu}$g/ml) > dichloroacetylshikonin (0.059${\mu}$g/ml) > monochloroacetylshikonin ($ED_{50}$, 0.142${\mu}$g/ml). Thus, the electron withdrawing effect seems to be important for the cytotoxicity of chloroacetylshikonin derivatives. Consistent with the above, dichloroacetylshikonin (T/C. 182%) and trifluoroacetylshikonin (195%) showed higher T/C values than monochloroacetyl-(T/C, 122%), monobromoacetyl-(T/C, 154%) and monoiodoacetylshikonin (T/C, 117%) derivatives. Haloacetylshikonin derivatives showing lower cytoxic activities against L1210 cells exhibited lower T/C values. It seems that there is a relationship between the cytoxicity of haloacetylshikonin and their antitumor activity.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.16-23
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• 2002

Physical properties of composite resins such as strength, resistance to wear, discoloration, etc depend on the degree of conversion of the resin components. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the thickness of tooth structure penetrated by light and applied light curing time. The coronal portions of extracted human teeth (one anterior tooth, three posterior tooth) was embedded by pink denture material. the mounted teeth were cut into three illumination sections (1mm thickness enamel section, 1mm thickness dentin section, 2mm thicknes dentin section) and one backing section with cutting wheel. Thin resin films were made by using 6kg pressure between slide glass during 5 minutes Thin resin film was light cured on coupled illumination section during 40sec, 80sec and 120sec. each illumination section was coupled as follows; no tooth structure(X), ename section(E), enamel section + 1mm dentin section(ED1), enamel section + 2mm dentin section(ED2), enamel section + 1mm dentin section + 2mm dentin section(EDD). To simulate the clinical situation more closely, thin resin films was cured against a backing section of tooth structure. The degree of conversion of carbon double bonds to single bonds in the resin films were examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows ; 1 As curing time was increased, conversion rate was increased and as tooth thickness which was penetrated by curing light was increased, conversion rate was decreased. 2. At all tooth thickness groups, conversion rate between 80sec and 120sec was not significantly increased(P＞0.05). 3. At 40sec group and 80sec, conversion rate between no tooth structure(X) group and 1mm enamel section(E) group was not significantly decreased(P＞0.05). 4. At 80sec group and 120sec, conversion rate between 1mm enamel section(E) group and 1mm enamel section + 1mm dentin section(ED1) group was not significantly decreased(P＞0.05).

• 한국도서관정보학회지
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• 제32권3호
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• pp.199-226
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• 2001

이 연구는 한국의 목록규칙 변천과정에 관한 연속연구의 한 부분으로서, '국제표준화 시기'(1954년의$\boxDr$韓 圖書編目法$\boxUl$ $\boxDr$KORMARC 단행본실험용포맷$\boxUl$이 개발된 1980년 이전까지)를 중심으로 다루었다. 이 시기 한국에서 편찬된 목록규칙으로는 $\boxDr$韓 圖書編目法$\boxUl$, $\boxDr$東書編目規程(草)$\boxUl$, $\boxDr$寒國目錄規則$\boxUl$ 초판과 수정판을 들 수 있다. 이 연구에서는 이들 목록규칙의 체계, 내용의 특성을 개관하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.157-160
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• 1999

Aluminum 4343(filler thickness ; 10${\mu}{\textrm}{m}$/Al 3N03(core 80${\mu}{\textrm}{m}$)/Al 4343(filler 10${\mu}{\textrm}{m}$) clad sheet which is recently developed as brazing sheet materials for automotive condensers was fabricated by castinglongrightarrowhot rollinglongrightarrowcold rollinglongrightarrowintermediate annealing(IA)longrightarrowfinal cold rolling(CR). and the effect of IA/CR conditions on microstructure and sagging resistance were investigated the sheet which were fabricated by optimum conditions (IA'ed at 42$0^{\circ}C$ followed by CR'ed to 20~45%) showed good sagging resistance because the core obtained a coarsely recrystallized grain structure during brazing and consequently inhibited filled alloy penetration into the core.

• Archives of Pharmacal Research
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• 제16권3호
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• pp.219-226
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• 1993

For the analysis of structure relationship of ar-turmerone analogues, the compounds containing the various substituents on the phenyl ring and 1(or 2)-naphthyl group in the place of phenyl of ar-turmerone were prepared and tested their cytotoxicity against HL-60, K-562, and L1210 leukemia cells in vitro. The substituents at para position are methoxy, phenoxy, methyl, trifluoromethyl, fluoro, and chloro. At meta position methoxy, methyl, trifluoromethyl, or chloro groups at ortho position mathoxy or chloro group were introduced. Against HL-60 and K-562 cells, $ED_{50}$ values of the analogues are ranged from 0.8 to $30.0\;\mu{g/ml}$. Againste L1210 cell, these are located more than $20.0\;\mu{g/ml}$. However, 5-carbone-thoxy-2-methyl-6(1-naphthyl)-2-octen-4-one (5n)possesses $ED_{50}$ valuses 0.8, 2.1, $6.5\;\mu{g/ml}$ against HL-60, L1210 cells, respectively. The electronic nature of the substituents on phenyl ring of ar-tumerone dose not affect the biological activity. Therefore the flat structure of aromatic potion of ar-tumerone analogues is the more important factor for their activity rather than its electronic nature. The potentiation of the cytotoxicity with the enlargement of aromatic ring region also supports the importance of the plane structure of this area. The restriction of the single bond rotation between C-6 and aromatic ring through the introduction of substituents at the ortho position of phenyl ring and the increment of size of alkyl group at C-6 position enhances the activity. Therefore the effective conformation should by the one having the orthogonal arrangement between the aromatic ring and the side chain.