• Korean Journal of Pharmacognosy
• /
• v.33 no.3 s.130
• /
• pp.182-186
• /
• 2002

The Coptidis rhizoma is known for containing protoberberine alkaloids. Berberine, coptisine and palmatine are the major constituents of protoberberine alkaloids. The alkaloids were isolated and determined by forming complex compounds from Coptidis rhizoma in preparation I(Sam-Hwang-Sa-Sim-Tang) and II(Hwang-Ryen-Tang). For the determination of these alkaloids, a new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex compound ion. The absorbance of alkaloidal complex compounds in l.2-dichloroethane solution was measured at 625 nm. Calibration curve for the alkaloids isolated from Coptidis rhizoma was linear over the concentration range of 0.2-0.3 mg/ml. The method was proved to be rapid, simple and reliable for the isolation and the determination of the alkaloids in Coptidis rhizoma preparation I and II.

• Toxicological Research
• /
• v.19 no.4
• /
• pp.325-330
• /
• 2003

The effects of estrogen on apoptosis induced by 2,3,7,8-tetrachlorodibenzo-p-doxin (TCDD) were examined in cultured MCF-7 cells. TCDD stimulated apoptosis and inhibited the expression of bcl-2 gene in MCF-7 cells grown in the media supplemented with 10% fetal bovine serum. However, TCDD failed to induce apoptosis if cells were grown in the media deprived of all estrogen-like compounds. Removal of estrogen-like compounds from the growth media also led to the activation of bcl-2 gene expression in cells treated with TCDD. Combined treatment of estrogen with TCDD abrogated the binding of Aryl hydrocarbon Receptor (AhR)-TCDD complex to Dioxin response element (DRE) of bcl-2 gene leading to the inhibition of bcl-2 gene expression as well as stimulation of apoptosis. The present study suggests that the binding of estrogen receptor (ER)-estrogen complex to the estrogen responsive element (E) interferes with the binding of AhR- TCDD complex to the DRE and inhibits the bcl-2 expression.

• Journal of Environmental Science International
• /
• v.5 no.1
• /
• pp.7-14
• /
• 1996

Two experiments were conducted to evaluate breathing zone air quality in Taegu, using automatic analyzers for four air quality standards($SO_2$, $NO_2$, CO, and $O_3$). First, air target compounds were measured for 8 to 12 hours in each of two commercial areas and five residential areas. Second, air target compounds were hourly measured for 24 hours in each of two commercial areas, two residential areas, and an industrial complex area. Based on the first experiment the breathing zone air was more polluted in the commercial area as compared to the residential area, while the second experiment showed that the breathing zone air was polluted rather in the residential are3 as compared to the commercial area. The second experiment also indicated that there was some variation of breathing zone air concentration with time and measuring sites. Diurnal variation of breathing zone air concentrations was consistent with previous studies which measured at building height. The highest breathing zone air concentration was shown in Seongseo industrial complex area. An unusual finding of this study was that $SO_2$ concentration in the breathing zone air of Bisandong, a typical residential area of Taegu, was higher than that of other residential areas, even higher than that of Seongseo industrial complex area.

• Journal of Electrochemical Science and Technology
• /
• v.10 no.1
• /
• pp.29-36
• /
• 2019

Corrosion inhibition by synthesised ligand, 2-acetylpyridine 4-ethyl-3-thiosemicarbazone (HAcETSc) and its tin(IV) complex, dichlorobutyltin(IV) 2-acetylpyridine 4-ethyl-3-thiosemicarbazone ($Sn(HAcETSc)BuCl_2$) on mild steel in 1 M hydrochloric acid (HCl) was studied using weight loss measurement, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The inhibition efficiency increases by increasing the inhibitor concentrations. The polarisation study showed that both synthesised compounds were mixed type inhibitors. The electrochemical impedance study showed that the presence of inhibitors caused the charge transfer resistance to increase as the concentration of inhibitors increased. The adsorption of these compounds on mild steel surface was found to obey Langmuir's adsorption isotherm with the free energy of adsorption ${\Delta}G{^o}_{ads}$ of -3.7 kJ/mol and -7.7 kJ/mol for ligand and complex respectively, indicating physisorption interaction between the inhibitors and 1 M HCl solution.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2005.11a
• /
• pp.446-448
• /
• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2004.11a
• /
• pp.393-394
• /
• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.11a
• /
• pp.283-284
• /
• 2000

석유화학, 비철금속공단, 조선 및 기계공단 등과 같은 대형 산업단지를 가진 울산지역의 대기오염은 타 지역에 비하여 꽤 높은 것으로 보고되고 있다. 또한 울산지역은 인구가 백만이 넘는 대형도시이고, 사람과 각종 공단 생산제품을 수송하기 위한 교통밀도도 꽤 높으므로 많은 양의 휘발성 유기화합물(Volatile Organic Compounds : VOCs)이 배출되고 있다. 흔히 VOC는 대류권 오존 농도의 전구체로서 역할을 하여 대류권 오존농도 감소를 위한 연구가 활발히 진행되고 있다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 1999.06a
• /
• pp.271-276
• /
• 1999

미국을 비롯한 선진국들은 이미 휘발성 유기화합물(volatile organic compounds) 과 독성 중금속(toxic metals)을 비롯한 유해 대기오염물(hazardous air pollutants)에 대해 ATEOS (Airborne Toxic Element and Organic Species), TEAM(Total Exposure Assessment Measurement) 연구등의 대규모 연구를 통하여 인체에 미치는 영향이 가장 큰 물질군이 휘발성 유기화합물임을 밝혀낸 바 있다. (중략)

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2001.10a
• /
• pp.101-102
• /
• 2001

Antimutagens, including diverse compounds of botanical origin, offer some promise of reducing the risk posed by exposure to mutagens. Caution is warranted, however, as there may sometimes be a delicate balance between antimutagenic effects and potentiating effects of the same compounds. We studied effects of the antimutagens spermidine (SPD) and cysteamine (CSM) on the genetic activity of the radiomimetic cancer chemotherapy drug bleomycin (BLM).(omitted)

• Journal of the Korean Ceramic Society
• /
• v.34 no.7
• /
• pp.685-692
• /
• 1997

Effects of sintering temperature and time on the phase formation, the characteristics of sintering and electrical behaviors of NASICON compounds with Na3Zr2Si2PO12 and Na3.2Zr1.3Si2.2P0.8O10.5 compositions synthesized by solid state reaction were investigated. Maximum relative densities of 96% and 91% were obtained for Na3Zr2Si2PO12 and Na3.2Zr1.3Si2.2P0.8O10.5 compounds, respectively. Complex impedance analysis in a frequency range below 4 MHz was performed to measure the ionic conductivity and migration barrier height of the compounds at RT-30$0^{\circ}C$. The maximum ionic conductivity and the minimum migration barrier height were 0.45 ohm-1cm-1 and 0.07 eV, respectively. The migration barrier height of the high temperature form (space group : R3c) is about 30-40% of that of the low temperature form (space group : C2/c) in two NASICON compounds. Ionic conductivity increases with increasing sinterability, and the presence of glass phase in Na3.2Zr1.3Si2.2P0.8O10.5 compounds lowers significantly ionic conductivity at temperatures above 14$0^{\circ}C$.