• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.7-14
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• 2008

In this paper, we designed the HVIC(High Voltage Gate Driver IC) which has improved noise immunity characteristics and high driving capability. Operating frequency and input voltage range of the designed HVIC is up to 500kHz and 650V, respectively. Noise protection and schmitt trigger circuit is included in the high-side level shifter of designed IC which has very high dv/dt noise immunity characteristic(up to 50V/ns). And also, rower dissipation of high-side level shifter with designed short-pulse generation circuit decreased more that 40% compare with conventional circuit. In addition, designed HVIC includes protection and UVLO circuit to prevent cross-conduction of power switch and sense power supply voltage of driving section, respectively. Protection and UVLO circuit can improve the stability of the designed HVIC. Spectre and Pspice circuit simulator were used to verify the operating characteristics of the designed HVIC.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.1
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• pp.34-40
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• 1998

For applicating to 10-Gbit/s optical transimission systems, we have designed and fabricated a laser driver IC with extremely-high-operation-frequencies using AlGaAs/GaAs heterojunction bipolar transistors (HBTs), and have investigated its performances. Circuits design andsimulation were performed using SPICE and LIBRA. A discrete AlGaAs/GaAs HBT with the emitter area of 1.5*10 .mu.m$^{2}$, used for the circuit fabrication, exhibited cutoff frequency of 63 GHz andmaximum osciallation frquency of 50 GHZ. After fabrication of MMICs, we observed the very wide bandwidth of DC~18 GHz and the S$_{21}$ gain of 17 dB for a laser driver IC from the on-wafer measurement. Metal-packaged laser driver IC showed the excellent eye opening, the modulation currents of 32 mA, the rise/fall time of 40 ps, measured at the data rates of 10-Gbit/s.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.205-210
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• 2014

Persicaria orientalis (L.) Spach (Po) and Potentilla fragarioides var. major Maxim (Pf) extracts were analyzed to investigate anti-inflammation through their suppressing effects on free radicals such as reactive oxygen species (ROS). In addition, with regard to Po and Pf, an analysis was conducted of their inhibitory effect on nitric oxide, which is produced in lipopolysaccharide (LPS)-treated murine macrophage RAW 264.7 cells, and their inhibitory effect on the translocation of the nucleus of nuclear factor-kappa B (NF-${\kappa}B$). The $IC_{50}$ value of ROS, which was induced by $50{\mu}M$ 3-morpholinosydnonimine hydrochloride (SIN-1), was found to be $23.35{\pm}1.27{\mu}g/mL$ due to the effect of the Po extract, and $8.46{\pm}1.22{\mu}g/mL$ due to the effect of the Pf extract. In addition, the $IC_{50}$ value of peroxynitrite treated with the Po extract was $2.19{\pm}0.04{\mu}g/mL$, whereas that of peroxynitrite treated with the Pf extract was $0.80{\pm}0.02{\mu}g/mL$. ROS and peroxynitrite were induced by $50{\mu}M$ 3-morpholinosydnonimine hydrochloride. There was an increase in the amount of nitric oxide in the RAW 264.7 cells treated with LPS ($1{\mu}g/mL$), whereas the level of NO was observed to significantly and dose-dependently decrease in the cells treated with Po and Pf. The amount of nitric oxide produced by the group treated with $10{\mu}g/mL$ of the Pf extract was $11.45{\pm}0.57{\mu}M$. Furthermore, the Po extracts inhibited the translocation of the nucleus of NF-${\kappa}B$ in LPS-treated RAW 264.7 cells. Therefore, it is highly possible that Po and Pf have anti-inflammatory properties.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1571-1576
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• 2012

A diarylurea compound 1 possessing pyrrolo[3,2-$c$]pyridine nucleus was designed and synthesized with structure similarity to Sorafenib. Compound 1 was tested over 60-cancer cell line panel at a single dose concentration of 10 ${\mu}M$ and showed high activity. It was further tested in a five-dose mode to determine its $IC_{50}$, TGI, and $LC_{50}$ values over the 60 cell lines. Compound 1 showed high potency and good efficacy, and was accordingly tested at a single dose concentration of 10 ${\mu}M$ over a panel of 40 kinases. At this concentration, it completely inhibited the enzymatic activities of a number of oncogenic kinases, including ABL, ALK, c-RAF, FLT3, KDR, and TrkB. The target compound was subsequently tested over these 6 kinases in 10-dose testing mode in order to determine its $IC_{50}$ values.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.127-127
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• 2001

Chitosan에 Ttichoderma viride 유래의 cellulase를 처리하여 효소분해함으로써 고분자량 chitooligosaccharides를 얻었다. 생산된 올리고당을 HPLC로 분석한 결과 octamer 이상의 것이 전체 올리고당 중 49.3%에 달하는 비교적 고분자 화합물로 구성된 chitooligosaccharides의 혼합물이었다. MTT검색법에 의하여 고분자량 chitooligosaccha- rides의 정상세포주와 암세포주에 대한 세포독성을 실험하였다. 정상세포주인 아프리카 초록원숭이의 신장세포에 대한 $IC_{50}$/(50% 저해농도)값은 1,107.95$\mu$g/ml로 정상세포에 대한 독성은 거의 없었다. 폐암세포주인 A549, 방광암세포주인 J82, 대장암세포주인 SNU-C4, 위암세포인 SNU-1, 유방암세포주인 ZR75-1에 대한 $IC_{50}$/값은 각각 421.06$\mu$g/ml, 417.99$\mu$g/ml, 445.54$\mu$g/ml, 380,65$\mu$g/ml, 460.49$\mu$g/ml로 in vitro 종양세포 증식억제 활성을 나타내었다.

• Advances in Traditional Medicine
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• v.7 no.4
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• pp.385-389
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• 2007

We undertook the present study to evaluate different pharmacological as antioxidant, antibacterial and cytotoxic activities of the crude ethanolic extract of Momordica charantia (Family: Cucurbitaceae) leaves. The antioxidant property of the extract was assessed by 1, 1-diphenyl-2-picryl hydrazyl free radical scavenging assay. The extract showed antioxidant activity where $IC_{50}$ was about ${\sim}500{\mu}g/ml\;and\;IC_{50}$ was about ${\sim}10{\mu}g/ml$ for standard drug ascorbic acid. The extract showed a broad spectrum of antibacterial activity against all the tested gram positive and gram-negative bacteria where Staphylococcus epidermidis, Staphylococcus aureus, Salmonella typhi and Shigella dysenteriae were prominent. And the zones of inhibition were ranging from 8-15 mm for all the tested bacteria. Its cytotoxic property was evaluated by brine shrimp lethality bioassay. The extract showed significant lethality and the $LC_{50}$ value was $20{\mu}g/ml$.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.257-261
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• 2001

This paper presents the implementation of wide-band RFIC amplifier operating from near 50MHz to 3GHz using Tachyonics SiGe HBT foundry. Voltage shunt feedback is used for the flat gain and the broad band impedance matching. Initial design parameters are calculated using the low frequency small signal analysis. Since the HBT model was not available at the design time, discrete tuning board was made for fine tuning in the low frequency range. Fabricated amplifier shows 12dB gain with 1dB fluctuation and PldB reaches 15dBm at 850MHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.366-371
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• 2003

Biological efficacy assays, including antimicrobial, tyrosinase inhibition and anticancer activities of Chlorella hydrolysate, were carried out. In tyrosinase inhibition assay of Chlorella hydrolysate, $IC_{50}$(inhibitory concentration) was measured as 12%. Chlorella hydrolysate showed high anti-lung cancer activity of 88.2% at a concentration of 0.15%.

• Korean Journal of Clinical Pharmacy
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• v.8 no.2
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• pp.139-142
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• 1998

The effects of MeOH extracts from 28 herbal medicines on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and its activity was determined by fluoro-photometry using kynuramine as a substrate. Three MeOH extracts, Coptis japonica, Cinnamomum cassia and Poncirus trifoliate from the herbal medicines showed a strong inhibitory effect with less than $100\;{\mu}g/ml$ in their inhibitory amounts of $50\%$ ($IC_{50}$ values) on MAO activity. Four MeOH extracts including Evodia officinalis exhibited a mild inhibition of MAO activity with $100-200\;{\mu}g/ml$ in their $IC_{50}$ values.

• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.159-164
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• 2019

Zanthoxylum Peel is widely used as a common spice for a variety of foods. In the orient, it has also been used as traditional agents for treating diseases such as indigestion. Recently, Zanthoxylum Peel has been reported to have anti-cancer activity, anti-microbial activity, and anti-inflammatory activity. Chemical components are known sanshool compounds and xanthoxylin. In this study, we were carried out to investigate the constituents of inhibiting a drug metabolizing enzyme CYP3A4 from Zanthoxylum Peel. CYP3A4 is known as an enzyme involved in drug metabolism as monooxygenase containing the heme. As a result of experiment, we found that bergapten ($IC_{50}=18.21{\mu}M$) and quercetin ($IC_{50}=17.27{\mu}M$) isolated from EtOAc extract of Zanthoxylum Peel showed remarkable CYP3A4-inhibiting activities. Structures of the isolated active compounds were established by chemical and spectroscopic means.