• 한국축산식품학회지
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• 제39권6호
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• pp.966-979
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• 2019

Muscle-based by-products are often undervalued although commonly reported having a high amount of natural bioactive peptides. In this study, elastin was isolated from the protein of broiler hen skin while its hydrolysate was prepared using Elastase. Assessment of antioxidative properties of elastin-based hydrolysate (EBH) was based on three different assays; 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical and metal chelating ability. The EBH was purified further using ultrafiltration, gel filtration and Reverse- Phase High-Performance Liquid Chromatography (RP-HPLC). The IC₅₀ of ABTS radical activities for EBH were decreased as EBH further purified using ultrafiltration (EBH III; 0.66 mg/mL)>gel filtration (EB-II; 0.42 mg/mL)>RP-HPLC (EB-II4; 0.12 mg/mL). The sequential identification of the peptide was done by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/ TOF-MS) of the potent fractions obtained from RP-HPLC (EB-II4). The presence of hydrophobic amino acids (Val and Pro) in the peptide sequences could potentially contribute to the high antioxidant activity of EBH. The sequences GAHTGPRKPFKPR, GMPGFDVR and ADASVLPK were identified as antioxidant peptides. In conclusion, the antioxidative potential from poultry skin specifically from elastin is evident and can be explored to be used in many applications such as health and pharmaceutical purposes.

• Preventive Nutrition and Food Science
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• 제13권3호
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• pp.196-203
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• 2008

Hwangtae, dried Alaska pollack, is a major storage product in the fish processing industry. Hwangtae is prepared by removing the internal organs and drying outdoors during the cold witner months by allowing it to thaw during the daytime and re-freeze at night under sub-zero ($-10^{\circ}C$) conditions and gradually dry from December until the next April for around 5 months from Myungtae. In this study, ground Hwangtae was hydrolyzed using two proteolytic enzymes (pepsin and alcalase) which produced five soluble active peptides from Hwangtae (yellowish dried Pollack, Theragra chalcogramma) protein. Two different peptides with strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods of Sephadex G-25 gel, ion-exchange chromatography on a Sepharose-Sephadex C-25 gel, and high-performance liquid chromatography. The isolated peptides, APO1 and APO2, were composed of 16 and 13 amino acid residues, respectively. Both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The peptide with a molecular weight less than 1,000 Daltons (APACE) obtained from enzymatic hydrolysates of Hwangtae exhibited the highest ACE inhibitory activity. The APACE peptides was composed of 4 amino acid residues (Gly-Leu-Leu-Pro). These results suggest that Hwangtae hydrolysates could be a good source of peptides with ACE inhibitory activity. Biochemical analysis indicated that two 70 kDa peptides (APG1 and APG2) isolated from the hydrolysate had gelatinoytic activity, which was shown to be a calcium dependent protease type as showed by gelatin SDS PAGE.

• 전자공학회논문지S
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• 제36S권1호
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• pp.1-8
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• 1999

종합 서비스망에서, 트랙픽을 발생시키는 각각의 플로우에 대하여 QoS(Quality of Service)를 적절하게 제공하기위해서는 호스트와 라우터에 자원 예약뿐만 아니라 효율적인 트랙픽 스케쥴링이 채택되어야 한다. 본 논문에서는 가상시간이 선형적으로 증가하는 새로운 페어 큐잉 알고리즘에 제안한다. 본 논문에서 제안된 알고리즘은 각 플로우에 대하여 기존의 SCFQ(Self-Clocked Fair Queneing) 알고리즘과 유사한 구현 복잡성을 갖으면서 더 감소된 최대 지연와 평균 지연시간을 제공하고 공평성 측면에서도 개선됨을 보여준다. 또한 자신에게 할당된 대역폭보다 더 많은 트랙픽을 발생시키는 플로우에 의해 다른 플로우는 영향을 받지 않도록하는 독립성 특성 또한 SCFQ보다 더 좋은 성능을 보인다. 본 논문에서는 제안된 알고리즘에 대한 공평성을 증명했고, 최대지연과 평균지연시간에 대한 시뮬레이션 결과를 나타냈다.

• 한국전자파학회논문지
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• 제11권5호
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• pp.782-787
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• 2000

광대역 고출력 SP3T MMIC GaAs PIN 다이오드 스위치를 설계, 제작하고 특성을 측정하였다. 전력단속능력을 개선시키기 위하여 다이오드의 버퍼층을 저온 버퍼와 초격자 버퍼로 이루어진 2층 구조로 설계하였다. 개발된 다이오드의 항복전압은 65V이고 순방향 정압강하는 1.3V 이었다. MMIC 스위치는 마이크로스트립 라인형으로 구현되었고 인덕턴스가 낮은 via hole 공정을 이용하여 신호를 접지하였다. 평면형 구조보다 더 낮은 기생성분과 진성영역에서 고품질을 갖는 수직형 에피텍셜 PIN 구조를 사용하여 우수한 마이크로파 성능을 얻었다. 제작된 SP3T 스위치의 고출력 특성은 14.5GHz CW에서 입력전력을 8dBm부터 32dBM 까지 증가시킬 때 삽입손실은 0.6dB보다 작은, 분리도는 50dB보다 크게 측정되었다.

• 한국군사과학기술학회지
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• 제19권5호
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• pp.590-597
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• 2016

We designed the multiple scattering points generation system to simulate an actual situation of target signal for high range resolution radar system. This provides replicating the target signals and controlling the status of target signals for radar system. This is composed transmit antenna and multi target generator. Transmit antenna is waveguide array antenna and multi target generator has signal distribution module and control & power module. Multi target generator is able to provide the high isolation and variable output power. Moreover, in order to monitor all output signals of the multi target generator, the flows of signals are programed in control & power module. The performance is demonstrated using experimented results of high range resolution radar.

• 전기전자학회논문지
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• 제20권3호
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• pp.251-259
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• 2016

본 논문에서는 순차바이어스와 스위칭 타임 튜닝기법을 통한 반도체 송수신모듈(TRM : Transmitter and Receiver Module)의 강건성 향상 방법에 대해 기술한다. 기존의 회로설계는 TRM의 소형화로 인한 송신출력신호가 수신기로 유기되어 최소수신감도(MDS : Minimum Detection Signal) 개선에 초점을 맞추어졌으나, 평균고장시간(MTBF : Mean Time Between Failure)을 만족하지 못하고 빈번히 고장이 발생하는 문제가 있었다. 본 연구는 이러한 현상을 개선하는 방법으로 순차바이어스 및 스위칭 타임 튜닝기법을 제안한다. 첫 번째로 주요 고장증상 수집 및 원인을 추론하였으며, 두 번째로 개선방법을 도출하고 시스템에 적용하여 효과를 검증하였다. 제안한 방법을 적용하여 격리도 부족에 따른 빈번한 고장증상이 해소되었다.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2408-2412
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• 2013

We demonstrate herein the synthesis and modification of magnetic nanoparticles and its use in the immobilization of the lipase. Magnetic $Fe_3O_4$ nanoparticles (MNPs) were prepared by simple co-precipitation method in aqueous medium and then subsequently modified with tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethylenesilane (APTES). Silanization magnetic nanoparticles (SMNP) and amino magnetic nanomicrosphere (AMNP) were synthesized successfully. The morphology, structure, magnetic property and chemical composition of the synthetic MNP and its derivatives were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) analysis, X-ray diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analyses (TGA). All of these three nanoparticles exhibited good crystallization performance, apparent superparamagnetism, and the saturation magnetization of MNP, SMNP, AMNP were 47.9 emu/g, 33.0 emu/g and 19.5 emu/g, respectively. The amino content was 5.66%. The AMNP was used to immobilize lipase, and the maximum adsorption capacity of the protein was 26.3 mg/g. The maximum maintained activity (88 percent) was achieved while the amount of immobilized lipase was 23.7 mg $g^{-1}$. Immobilization of enzyme on the magnetic nanoparticles can facilitate the isolation of reaction products from reaction mixture and thus lowers the cost of enzyme application.

• 한국자원식물학회지
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• 제27권3호
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• pp.215-222
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• 2014

This study was conducted to isolate a compound with anticancer properties from the roots of Peucedanum japonicum Thunb. (Umbelliferae), and to evaluate the efficacy of that compound's anticancer activity. The $CHCl_3$ layer was purified via repeated column chromatography and recrystallization. The two compounds isolated from $CHCl_3$ layer were identified via NMR spectroscopic analysis as (10E) 1,10-heptadecadiene-4,6-diyne-3,8,9-triol (Comp. I) and anomalin (Comp. II). (10E) 1,10-heptadecadiene-4,6-diyne-3,8,9-triol was the first report from the roots of P. japonicum. MTT assays were conducted to evaluate the in vitro cytotoxic activities of Compounds I and II against the following human cancer cell lines: HeLa, HepG2, SNU-16, and AGS. Comp. I evidenced the most profound cytotoxic activity against HepG2 cells ($IC_{50}=6.04{\mu}g/mL$), and Comp. II exhibited the most profound cytotoxic activity against SNU-16 cells ($IC_{50}=18.24{\mu}g/mL$) among the human cancer cell lines tested in this study. However, no significant cell death was observed in the CCD-25Lu human normal lung fibroblast cells. Quantitative analysis using UPLC (Ultra Performance Liquid Chromatography) showed that the roots of P. japonicum contained 0.015 (Comp. I) and 1.69 mg/g (Comp. II) of these compounds.

• 한국식품과학회지
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• 제47권2호
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• pp.170-175
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• 2015

본 연구에서는 국산배의 기능학적 우수성 증명을 위해 국산배로부터 생리활성 화합물을 밝히고자 하였다. 이에 배 과피 MeOH 추출물을 용매분획하여 얻은 EtOAc-산성획분을 대상으로 Sephadex LH-20 column chromatography와 ODS-HPLC를 이용하여 순차적으로 정제를 행하여 2종의 화합물을 단리하였다. 단리된 화합물 1과 2는 MS 및 NMR 분석을 통하여 각각 quercetin 3-O-${\beta}$-Dglucopyranoside(화합물 1)와 3,5,6,7,8,3',4'-heptahydroxyflavan [(-)-dulcisflavan, 화합물 2)]으로 동정되었다. 단리된 화합물 1은 동양배로부터, 그리고 화합물 2는 배로부터 처음 동정된 화합물이다. 본 연구결과가 국산배의 기능학적 우수성 증명을 위한 기초자료로 활용되길 기대한다.

• 한국식품영양과학회지
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• 제38권5호
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• pp.653-656
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• 2009

생약재로 사용 중인 Angelica gigas Nakai의 decursin 및 decursinol angelate를 60% ethanol로 최종적으로 추출 후 recycling HPLC 및 HPLC/MS에 의해 각각을 분리하였다. 60% ethanol로 $-20^{\circ}C$에서 추출하였을 경우 95% 순도의 decursin 및 decursinol angelate를 얻을 수 있었고 10번 이상의 recycle를 통해서 순수한 decursin 및 decursinol angelate를 분리할 수 있었다. 분리한 decursin 및 decursinol angelate를 HPLC/MS를 통해 분자량을 확인하였을 경우 m/z=329($[M+H]^+$) 및 m/z=351($[M+Na]^+$)과 같은 결과를 얻을 수 있었다. 이 분리 방법을 통해 decursin 및 decursinol angelate를 통한 의약품 및 식품 등에 관한 여러 연구에 있어 두 물질 각각에 대한 약리학적 효과를 도출하는데 기여할 것이며, 물질표준화에 기여할 것으로 사료된다.