• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.227-230
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• 1997

The authors isolated four olefinic catechols, commonly referred to as urushiol, from the sap of Korean lacquer tree(Rhus vernicifera STOKES) with stronger antioxidative activities than $\alpha-tocopherol$. The hexane extract with a free radical scavenging activity was purified by silica and ODS gel column chromatography. The active compounds were identified by MS and $^1H-NMR$ as 3-[8'(Z),11'(Z),14'-pentadecatrienyl]catechol, 3-[8'(Z),11'(Z)-pentadecadienyl]catechol, 3-[8'(Z)-pentadecenyl] catechol, and 3-pentadecylcatechol. All of these compounds showed strong free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, in which 3-pentadecylacatechol exhibited the highest activity ($IC_{50}$: $1.2{\mu}g/ml$). They also showed a significant inhibitory activity on lipid peroxidation ($IC_{50}$: 2.1 - 3.5 ${\mu}g/ml$). The antioxidative activity of 3-pentadecylcatechol on DPPH radical and lipid peroxidation is approximately two times greater than that of $\alpha$-tocopherol. The results suggest that the urushiol derivatices may contribute to the preservative characteristics effective against oxidative stress and could be a good source for industrial applications including a coating material.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.549-552
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• 1988

KUIC_LED II is a two dimensional graphics editor for IC mask layout which breaks through the memory limit, maximum number of box is 2333, with overlay. It runs on IBM PC/AT with the ${\Omega}$/PC color graphics board. I/O data format is CIF(Caltech Intermediate Form). It is written, In 'C' language on MS_DOS.

• Food Science and Preservation
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• v.7 no.1
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• pp.103-107
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• 2000

Previously , the methanolic extract of peach sees was found to have a strong tyrosinase inhibitory activity in an in vitro assay. Several phenolic compunds were isolated from the seeds by solvent fractionation , Sephadex LH-20 chromatography, and preparative HPLC , and one of them showing strong tyrosinase inhibition was identified as benzoic acid by UV, IR, $^1$H/$^1$$^3$C-NMR, and EI-MS spectrsopy. Benzoic acid (IC50= 250$\mu\textrm{g}$/ml) and L-ascorbic acid (IC50=28$\mu\textrm{g}$/ml), well-known tyrosinase inhibitors. In particular , benzoic acid inhibited markedly the enzymatic browing (melanosis) of apple juices at low concentration of 0.01% and 0.05, comparable to that of L-ascorbic acid (P<0.05). these results suggest that benzoic acid, one of an effective food preservatives, may be potentially useful as a functional alternative to sulfites for the control of melanosis in fruit juices.

• Natural Product Sciences
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• v.13 no.2
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• pp.135-139
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• 2007

Four anthocyanins were isolated from the acidic alcoholic extract of Syzygium cumini fruits growing in Egypt: Pelargonidin-3-O-glucoside, pelargonidin-3,5-O-diglucoside, cyanidin-3-O-malonyl glucoside, and delphenidin-3-O-glucoside. They were identified by the chromatographic, TLC and PC, and spectral analyses, UV, $^1$H-NMR and FAB/MS. The fruits were found to contain 0.03 gm % anthocyanins calculated on fresh weight basis calculated by spectrophotometric assay. Cytotoxic activity of total alcoholic extract of the fruits was performed against several types of tumor cell lines using the SRB assay. The tested extract exhibited significant cytotoxic activity for MCF7 (breast carcinoma cell line) (IC$_{50}$= 5.9 ${\mu}$g/mL), while the IC$_{50}$ was > 10 ${\mu}$g/mL for both Hela (Cervix carcinoma cell line), HEPG2 (liver carcinoma cell line), H460 (Lung carcinoma cell line) and U251 (Brain carcinoma cell line).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.481-482
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• 2006

Chemical-mechanical polishing, the dominant technology for LSI planarization, is trending to play an important function in micro-electro mechanical systems (MEMS). However, MEMS CMP process has a couple of different characteristics in comparison to LSI device CMP since the feature size of MEMS is bigger than that of LSI devices. Preliminary CMP tests are performed to understand material removal rate (MRR) with blanket wafer under a couple of polishing pressure and velocity. Based on the blanket CMP data, this paper focuses on the consumable approach to enhance MEMS CMP by the adjustment of slurry and pad. As a mechanical tool, newly developed microstructured (MS) pad is applied to compare with conventional pad (IC 1400-k Nitta-Haas), which is fabricated by micro melding method of polyurethane. To understand the CMP characteristics in real time, in-situ friction force monitoring system was used. Finally, the topography change of poly-si MEMS structures is compared according to the pattern density, size and shape as polishing time goes on.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.134-134
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• 1998

The modulation of glycosidase activity by inhibitors is of great interest. Such compounds have been shown to be important tools in mechanistic studies on glycohydrolase as well as having promising therapeutic application. An ${\alpha}$-glucosidase inhibitor was isolated from culture filterates of Penicillium sp. The inhibitor was active against ${\alpha}$-glucosidase isolated from yeast and porcine small intestine. However, it showed no inhibition to Aspergillus ${\alpha}$-galactosidase, Escherichia coli ${\beta}$-galactosidase, and jack bean ${\alpha}$-mannosidase. The inhibitor was highly soluble in ether, methanol and chloroform. The inhibitor was purified using silica gel, Sephadex LH-20 column chromatography and reverse-phase HPLC. The inhibitory compound designated PA-7(IC$\sub$50/=35$\mu\textrm{g}$) was obtained as white powder. The structure of PA-7 was determined with spectroscopic data of EI-MS, FAB-MS, $^1$H, and $\^$13/C NMR. The inhibitor has a diketopiperazine moiety.

• Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.11.1-11.7
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• 2016

In this study, purified peptides from shrimp waste hydrolysates (SWHs) were examined for their inhibitory effects against ${\beta}$-secretase. During consecutive purification using a Sephadex G-25 column chromatography and high performance liquid chromatography on a C18 column, a potent ${\beta}$-secretase inhibitory peptide Asp-Val-Leu-Phe-His (629 Da) was isolated and identified from SWH24 by Q-TOF MS/MS and the $IC_{50}$ value was determined to be $92.70{\mu}M$. The ${\beta}$-secretase inhibition patterns of the purified peptides were found to be competitive. Among synthesized ${\beta}$-secretase inhibitory peptides, Leu-Phe-His had higher ${\beta}$-secretase inhibitory activity than the others. The result of this study suggests that the ${\beta}$-secretase inhibitory peptide derived from SWH24 could be potential candidates to develop nutraceuticals and pharmaceuticals.

• Mycobiology
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• v.41 no.3
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• pp.149-154
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• 2013

An ${\alpha}$-glucosidase inhibitor was developed from Aspergillus oryzae N159-1, which was screened from traditional fermented Korean foods. The intracellular concentration of the inhibitor reached its highest level when the fungus was cultured in tryptic soy broth medium at $27^{\circ}C$ for five days. The inhibitor was purified using a series of purification steps involving ultrafiltration, Sephadex G-25 gel permeation chromatography, strong cation exchange solid phase extraction, reverse-phase high performance liquid chromatography, and size exclusion chromatography. The final yield of the purification was 1.9%. Results of the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis indicated that the purified ${\alpha}$-glucosidase inhibitor was a tri-peptide, Pro-Phe-Pro, with the molecular weight of 360.1 Da. The IC50 value of the peptide against ${\alpha}$-glucosidase activity was 3.1 mg/mL. Using Lineweaver-Burk plot analysis, the inhibition pattern indicated that the inhibitor acts as a mixed type inhibitor.

• 전기의세계
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• v.28 no.7
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• pp.49-55
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• 1979

This paper describes the mechanisms which breaks A.C. over-current protection in low voltage load. For the high speed over-current protection, it consists of thyristor switching circuit by forced commutation, IC logic gate controlled circuit and over-current detector with reed switch. Under various duty conditions, breacker was carried out several experiments and discussions. The results are as follows; (1) over-current cut off is possible within a quarter cycle (4ms at 60Hz) and clear is at least ten times faster than its electromechanical equivalent. (2) as the forced commutation thyristor circuit breaker has capability of high speed break, equivalent surgy current capacity of switching thyristor is increased more than twenty times of its rated current. (3) breaker using solid state dose not produce any harmful arc during switching period. Therefore the breaker above described may be considered an effective over-current protector for soli state power devices in industrial applications.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.134-141
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• 2014

A testing inspection is one of the important in the industry, owing to determine the reliability and directivity of testing inspection results. Therefore, the quality assurance and quality control (QA/QC) work which performed by personnel not directly in the inventory compilation development, in testing inspection must be thoroughly considered. Some agencies for environmental test inspection, they sometimes misunderstood that the QA/QC was ended with proficiency testing performance and on-site assessment by a director. Thus, results were often calculated without QA/QC work by self manual when conducting test. The objective of this study was to improve reliability of testing and inspection agency through the QA/QC case study which basically performed to raising reliability of testing and inspection agency. In this study, it increased reliability of result by verifying calibration curve (IC, ICV, CCV), blank, accuracy (LCS, MS) and precision as QA/QC performance, while performing investigation of soil contamination in mining areas. This study suggests that reliability establishing method of test result and management method of analysis process, through the QA/QC instance of testing agency.