• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2085-2087
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• 1998

This paper presents the design method of a dimming electronic ballast for fluorescent lamps using a frequency control IC, and investigates the effects of circuit variables on its dimming characteristics. It is shown that effective dimming is possible with IC IR2151 for frequency control, and this leads to a feasible design of more smaller and cheaper dimming ballast. Five ballasts different in the values of the series inductance and capactance are designed, and their dimming characteristics are compared. As the result, the dimming range becomes more broader as the series inductance gets smaller and the capacitance larger. Thus appropriate selection of the values of L and C should be made according to the types of application site.

• Toxicological Research
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• 제17권4호
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• pp.303-308
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• 2001

The potential for a given anticholinesterase pesticide to exhibit age-related toxicity is essential information for an accurate and proper risk assessment of that compound. This investigation was designed to study the age-related toxicity of active metabolites of four organophosphates using in vitro detoxification measurement. The blood samples were collected from 1 month and 18 months old rats. The $IC_{50}$ values of mouse brain recombinant AChE of chlorpyrifos-oxon, diazoxon, malaoxon and paraoxon were 10.35, 112.84, 151.28 and 18.43 nM, respectively. When the plasma of young rats, and $CaCI_2$were added, the $IC_{50}$ values of mouse brain recombinant AChE of chlorpyrfos-oxon, diazoxon, malaoxon and paraoxon were 31.89, 164.25, 139.94 and 16.36 nM, respectively. The $IC_{50}$ values of mouse brain recombinant AChE of chlorpyrifos-oxon, diazoxon, malaoxon and paraoxon were changed to 136.840, 1244.45, 654.54 and 52.66 nM by A-esterases In adult rats. These results suggest that four organophosphates have a potential toxicity to exhibit age-related sensitivity.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.293-299
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• 2002

Cytotoxic and antimutagenic effects of a novel cis-$\varepsilon$-viniferin and five known stilbenes, transresveratrol, trans-$\varepsilon$-viniferin, gnetin H, suffruticosols A and B, isolated from the seeds of Paeonia lactiflora Pall. (Paeoniaceae) were determined against five different cancer cell lines, and mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Salmonella typhimurium TA100, respectively. Six stilbenes showed cytotoxic activity in a dose-dependent manner, and especially did potent cytotoxic activity against C6 (mouse glioma) cancer cell with $IC_{50}$ values ranging from 8.2 to $20.5{\;}{\mu\textrm{g}}/ml$. trans-Resveratrol showed significant cytotoxic activity against HepG2 (liver hepatoma) and HT-29 (colon) human cancer cell lines with $IC_{50}$ values of 11.8 and 25.2 g/ml, respectively. In contrast, trans-$\varepsilon$-viniferin and cis--viniferin, and gnetin H exhibited marked cytotoxic activity against Hela (cervicse) and MCF-7 (breast) human cancer cell lines with $IC_{50}$ values of 20.4, 21.5, and $12.9{\;}{\mu\textrm{g}}/ml$, respectively. However, suffruticosol A and B had less cytotoxic effect against all cancer cells except C6. Meanwhile, six stilbenes exerted antimutagenic activity in a dose-dependent fashion. Of them, trans-resveratrol exhibited the strongest antimutagenic effect against MNNG with $IC_{50}$ value of $27.0{\;}{\mu\textrm{g}}/plate$, while other five resveratrol oligomers also did moderate antimutagenic activity with $IC_{50}$ values ranging from 31.7 to $35.2{\;}{\mu\textrm{g}}/plate$.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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• pp.1806-1813
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• 2018

A new sesquiterpene lactone dimer [1], together with five known compounds (2-6), was isolated from the flowers of Inula britannica. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activities of these isolated compounds (1-6) against human neutrophil elastase (HNE) were also evaluated in vitro; compounds 1 and 6 exhibited significant inhibitory effects against HNE activity, with $IC_{50}$ values of 8.2 and $10.4{\mu}m$, respectively, comparable to that of epigallocatechin gallate (EGCG; $IC_{50}=10.9{\mu}M$). In addition, compounds 3 and 5 exhibited moderate HNE inhibitory effects, with $IC_{50}$ values of 21.9 and $42.5{\mu}M$, respectively. In contrast, compounds 2 and 4 exhibited no such activity ($IC_{50}$ > $100{\mu}M$). The mechanism by which 1 and 3 inhibited HNE was noncompetitive inhibition, with inhibition constant ($K_i$) values of 8.0 and $22.8{\mu}M$, respectively.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1898-1906
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• 2004

Nonclassical quinazolinone analogs I, II, and III, in which the glutamic acid moiety of the classical antifolates is substituted by phenylglycine, phenylalanine or aminobenzoic acid and their methyl esters, were synthesized and evaluated as lipophilic inhibitors of thymidylate synthase (TS). The target compounds were generally potent inhibitors of L. casei and human TS with $IC_{50}$ values within the narrow range of 0.2-10 ${\mu}$M and 0.003-0.03 ${\mu}$M, respectively. Further, most of the target compounds showed cytotoxicity against tumor cell lines of murine and human origin with $IC_{50}$ values of as low as 0.050 ${\mu}$M. Substitution of another hydroxyl or carboxylic acid/ester group at the phenyl ring further increased the potency of TS inhibition and cell growth inhibition. Most effective were compounds If and Ic in which extra carboxylic acid/ester was present at the phenyl ring with nanomolar $IC_{50}$ values of 0.0044 and 0.0093 ${\mu}$M against human TS and submicromolar cytotoxic growth inhibition against all four tumor cell lines.

• 대한물리의학회지
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• 제14권3호
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• pp.47-53
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• 2019

PURPOSE: This study measured the external pressure on abdomen during maximal inspiration. The study determined the correlation between the diaphragmatic contraction pressure and the lung capacities to verify whether or not the measured pressure values can represent diaphragmatic contractility. METHODS: The study included 32 healthy subjects (16 males and 16 females). The researchers fabricated their own diaphragmatic pressure belt (DiP Belt) to measure DCP. DiP Belt device was fixed on the front of the abdomen and the diaphragmatic contractility was measured during maximal inspiration. The lung capacities were measured using a portable digital spirometer device (Pony Fx, COSMED, Italy). A digital spirometer is a device that is used to test the flow of air entering and exiting the lungs. RESULTS: DCP showed significant positive correlations with vital capacity (VC), inspiratory reserve volume (IRV) and inspiratory capacity (IC). Among values of lung capacities, IC showed especially strong positive correlations with the DCP (r =.714, p<.010). For the males, DCP showed significant positive correlations with IRV and IC, and DCP showed significant negative correlation with the expiratory reserve volume (ERV). For the females, DCP showed significant positive correlation with tidal volume (VT), but any significant correlation was not found with any of the other values of lung capacities. CONCLUSION: DCP showed high correlations with IRV and IC associated with inspiratory capacity. Therefore, The DiP Belt can be looked upon as a simple device that is very useful for measuring diaphragmatic contractility.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.389-392
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• 1999

It is essential to estimate an effective inductance in a ground plane of muliti-layer IC package system in order to determine the simultaneous switching noise of the package. A new method to estimate the effective ground inductance in multi-layer IC package is presented. With the estimated ground plane inductance values, maximum switching noise variations according to the number of simultaneously switching drivers are investigated by developing a new SSN model. These results are verified by performing HSPICE simulation with the 0.35${\mu}{\textrm}{m}$ CMOS technology.

• 한국환경보건학회지
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• 제49권6호
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• pp.312-323
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• 2023

Background: Environmental concentrations of substances can be estimated by K-CHESAR based on main, industrial, and use categories (MC/IC/UC) and ECETOC TRA based on environmental or specific environmental categories (ERC or spERC). Objectives: Three different systems for estimating environmental concentrations were compared to figure out their order with possible reasons along with relationship of regional predicted environmental concentrations (PEC_regional) and final PEC_local for various uses of a substance. Methods: Typical uses of the case substance and their corresponding ERCs were selected from the webpage of the European Chemical Agency. Proper MC/IC/UC and spERC were assigned to each ERC. Emission fractions were compared for each assessment code from the available database. PECs were calculated by three estimating systems: K-CHESAR using MC/IC/UC, ECETOC TRA using ERC, and ECETOC TRA using spERC with their default values for input parameters. Percentage of PEC_regional to PEC_local were manually calculated for each use. Results: Emission factors decreased in the order of ERC > MC/IC/UC > spERC. Values of the final PEC_local derived as sum of PEC_regional and Clocal decreased in the order of calculations using ECETOC TRA-ERC>KCHESAR with MC/IC/UC>ECETOC TRA-spERC for all environmental media. Percentages of PEC_{regional,water} to PEC_local,water ranged from 0 to 10.3% in industrial uses calculated with MC/IC/UC and ERC but 96.3 to 100% in wide dispersive uses of ERC and spERC where values of C_local,water are estimated to be very low. Conclusions: ECETOC TRA generated the most refined PNEC values with spERC and the least with ERC, while K-CHESAR with MC/IC/UC generated values between the two results. The ratio of PEC_regional to PEC_local can be a good measure for performing suitable estimation of PNECs according to use.

• Composites Research
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• 제12권5호
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• pp.40-53
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• 1999

저속시험 및 약 11.4m/s까지의 고속시험을 받는 다방향 탄소섬유/에폭시 복합적층판의 층간파괴거동에 대해 양외팔보(DCB)시험편을 이용하여 연구했다. 모드I의 하중을 1.0m/s이상으로 가한 결과 하중-시간곡선에 동적효과가 발생하여, 시험속도에 비례하는 단순관게식으로 예상되는 것보다 더 큰 균열속도가 나타났다. 시험편 개구변위와 균열길이만을 사용하는 수정된 선형보해석식은 동적인 층간파괴에너지$G_{IC}$를 평가하기 위해 유효했다. 또한 굽힘탕선계수의 실측값은 시험속도의 증가에 다라 증가했는데, 이를 $G_{IC}$의 평가시에 고려했다. 시험속도가 1.0m/s까지 증가할 때, 균열개시 및 정지시의 $G_{IC}$값은 변화가 없었으나, 11.4m/s의 속도에서 최대 GIC값은 섬유가교효과의 증대로 크게 증가했다. 또한 초기균열길이가 길수록 고속시의 최대GIC값은 저하했다.

• 약학회지
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• 제42권6호
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• pp.634-638
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• 1998

The effects of MeOH extracts from 88 herbal medicines on monoamine oxidase (MAO) acitivity were investigated. MAO was purified from mouse brain and its activity was determined by fluorospectrophotometer using kynuramine as a substrate. The $K_m\;and\;V_{max}$ values (n=4) of MAO were $78.2{\pm}4.0\;{\mu}M$ and $0.65{\pm}0.05$ nmol/min/mg protein, respectively. Four MeOH extracts from Melilotus sauvelolens, Eupatorium lindleyanum Bupleurum longiradiatum and Sorbaria sirbiforia showed a strong inhibitory effect with less than $100{\mu}g/ml$ in their $IC_{50}$ values on MAO activity. Six MeOH extracts including Agastache rugosa showed a mild inhibitory effect with 100~200${\mu}$g/ml in their $IC_{50}$ values. Twenty-two MeOH extracts including Melandryum seoulense exhibited a week inhibition of MAO activity with 200~300${\mu}$g/ml in their $IC_{50}$ values.