• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.685-688
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• 2001

A gas chromatography/mass spectrometric assay method has been developed for the simultaneous determination of benzidine (BZ), N-acetyl benzidine (ABZ) and N,N-diacetyl benzidine (DABZ) in rat urine. BZ, ABZ and DABZ were extracted from urine at pH 8 with ethyl ether. Conjugated urinary metabolites were extracted at pH 8 after hydrolysis with 1 M HCl for 30 min at 100 $^{\circ}C.$ The dried extract was dissolved in 100 ${\mu}{\ell}$ of ethylacetate and then injected in gas chromatography-mass spectrometric (GC-MS) system without further purification or modification. BZ, ABZ and DABZ have good chromatographic properties and offer very sensitive response for the EI-MS (SIM) without any derivatization. The recoveries for BZ, ABZ and DABZ were about 98.0, 81.8 and 71.4%, respectively, at pH 8.0 and the concentration of 5.0 ng/mL. The coefficients of variation of BZ and ABZ were less than 9.5% from 0.1 to 100 ng/mL and that of DABZ was less than 13% in the same concentration range. The detection limits of the assay were 0.01 ng/mL for both BZ and ABZ, and 0.05 ng/mL for DABZ in urine or plasma 1.0 mL.

• 분석과학
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• 제19권1호
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• pp.107-114
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• 2006

본 연구에서는 trimethylsilyl (TMS) 및 trifluoroacetyl (TFA)유도체화를 이용하여 소변여지에서 대사이상 질환을 신속하게 스크리닝하는 GC/MS 분석법을 개발하였다. 유기산과 아미노산을 동시에 유도체화하기 위해 메틸오렌지를 지시약으로 하여 $60^{\circ}C-70^{\circ}C$에서 15-20 분간 카르복실기는 TMS로 아미노기는 TFA로 유도체한 후 GC/MS-SIM으로 분석하였다. 유기산과 아미노산의 직선성의 범위는 0.001-50 mg이었고, 소변에서의 검출한계는 10-200 ng, 정량한계는 80-900 ng 이었다. 직선성을 보이는 범위에서의 상관계수(R2)는 0.994-0.998이었고, 회수율은 methylcitric acid와 glycine을 제외하고 80-100%를 보였다. 이 방법은 기존의 유기산분석에는 GC/MS를 아미노산 분석에는 아미노산분석기를 사용하는 것과 비교할 때 GC/MS만 사용하여 동시에 유기산과 아미노산을 분석함으로써 전처리가 간단하고 짧은 분석시간과 우수한 감도, 정확도, 정밀도를 보여 주었다. 정상인과 대사이상질환 환자의 검체에 적용해 보았을 때, 본 분석방법은 유기산과 아미노산대사이상의 유전성대사질환 환자의 스크리닝, 진단 및 모니터링에 임상적으로 유용함을 보여주었다.

• ETRI Journal
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• 제32권2호
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• pp.255-264
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• 2010

Interference scenarios and methodologies between a terrestrial mobile service (MS) system and mobile-satellite service (MSS) system in a co-channel environment are established. Taking into account a practical deployment situation for both systems, we perform computational simulation of interference in terms of carrier-to-interference ratio (C/I) and interference-to-noise ratio (I/N) to evaluate the cofrequency interference from an MS system into an MSS system, and from an MSS system into an MS system, respectively. The methodology and results can be used as a guide when planning the deployment of MSS and MS systems with no unacceptable interference impact between them.

• Mass Spectrometry Letters
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• 제5권2호
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• pp.49-51
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• 2014

The effectiveness of tertiary matrices composed of the combination of three common matrices (dihydrobenzoic acid (DHB), ${\alpha}$-cyano-4-hydroxycinnamic acid (CHCA), and sinapinic acid (SA)) was compared with that of single or binary matrices in the analysis of polyethylene glycol (PEG) polymers ranging from 1400 to 10000 Da using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A tertiary matrix of 2,5-DHB+CHCA+SA was the most effective in terms of S/N ratios. CHCA and CHCA+SA produced the highest S/N ratios among the single matrices and the binary matrices, respectively. The improvement observed when using a tertiary matrix in analyses of PEG polymers by MALDI-TOF MS is believed to be due to the uniform morphology of the MALDI sample spots and synergistic effects arising from the mixture of the three matrix materials.

• 한국정보처리학회논문지
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• 제6권3호
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• pp.571-579
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• 1999

A Macro-Star graph which has a star graph as a basic module has node symmetry, maximum fault tolerance, and hierarchical decomposition property. And, it is an interconnection network which improves a network cost against a star graph. A matrix star graph also has such good properties of a Macro-Star graph and is an interconnection network which has a lower network cost than a Maco-Star graph. In this paper, we propose a method to embed between a Macro-Star graph and a matrix star graph. We show that a Macro-Star graph MS(k, n) can be embedded into a matrix star graph MS\ulcorner with dilation 2. In addition, we show that a matrix star graph MS\ulcorner can be embedded into a Macro-Star graph MS(k,n+1) with dilation 4 and average dilation 3 or less as well. This result means that several algorithms developed in a star graph can be simulated in a matrix star graph with constant cost.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.708-711
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• 2017

전기적 신호의 이상으로 발생하는 심방 부정맥은 심방세동으로 발전하는 대표적 심장 질환이다. 이러한 원인에는 세포 내 이온 채널의 유전적 결함으로 인한 기전이 알려져 있다. 지속적인 연구로 밝혀진 대표적인 유전적 질환 중 하나로서 KCNH2 유전자 돌연변이가 있다. 본 연구에서는 KCNH2 유전자 돌연변이가 심방부정맥을 유발하는 연관성연구를 기반으로 심실에서의 심장 질환 발현 연관성을 확인하고 심실부정맥과 심실세동 가능성을 예측하였다. 이를 위해 Ten tusscher 세포 모델에 KCNH2 유전자의 N588K, L532P 변이를 적용하여 2차원과 3차원 시뮬레이션을 진행하였다. wild-type(WT)과 mutant-type(MT)의 전기전도 패턴을 비교했다. 그 결과 WT의 전도파형이 일찍 자가소멸(self-termination) 되는 것과 대조적으로 MT는 회귀성 파형이 유지되었다(WT : 3.6초간 유지, MT : 지속적). 따라서 본 연구를 통해 KCNH2 유전자 돌연변이가 심실 조직의 취약성 (Action Potential Duration 감소, WT : 270 ms, N588K : 130 ms, L532P : 100 ms)을 증가시켜 부정맥의 요인이 됨을 확인하였다.

• Elastomers and Composites
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• 제40권1호
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• pp.45-52
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• 2005

풀러렌[$C_{60}$]은 3-chloroperoxy benzoic acid, benzoyl peroxide, trichloroisocyanuric acid, chromium(VI) oxide 등의 산화제를 사용하여 마이크로파 조건에서 반응시켜 풀러렌 산화물[$C_{60}(O)_n$] ($n=1{\sim}4$ or n=1)을 합성하였다. 동일한 마이크로파 조건에서 여러 가지 산화제와 풀러렌[$C_{60}$]의 고체상태 반응성은 3-chloroperoxy benzoic acid>benzoyl peroxide>trichloroisocyanuric acid$\simeq$chromium(VI) oxide 순으로 증가함을 나타냈다. MALDI-TOF-MS, UV-visible, 그리고 HPLC를 사용하여 분석한 결과 생성된 풀러렌 산화물은[$C_{60}(O)_n$] ($n=1{\sim}4$ or n=1)임을 알 수 있었다.

• Journal of Plant Biotechnology
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• 제30권1호
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• pp.53-58
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• 2003

여러가지 생장조절제를 첨가한 MS배지에 참나리의 기내배양 소인편과 실생인편을 치상하여 재분화 과정을 알아보았다. 소인편의 부정아 발생은 BAP 1.0mg/L와 NAA 0.1 mg/L을 혼합 처리한 MS배지에서 4주간 배양했을 때 가장 왕성하게 일어났으며, 실생인편의 부정아 발생률은 BAP 0.5mg/L와 NAA 0.1 mg/L에서 4주간 암배양했을 때 가장 높았다. 소인편의 캘러스 발생은 BAP 0.1 mg/L와 2,4-D 1.0 mg/L 혼합 처리구에서 가장 높았다. 또한. 캘러스의 재분화는 NAA 0.5 mg/L와 BAP 0.1 mg/L를 혼합 처리한 MS배지에서 8주간 명배양했을 때 가장 높았다. 뿌리는 MS배지에서 쉽게 발달되었으며, 8주 후 굵고 긴 뿌리를 갖춘 완전한 재분화 식물체로 성장하여 화분에 이식하였다. 참나리의 재분화 전, 후의 염색체 수는 모두 2n=24로서 조직배양에 의한 염색체수의 변화가 없음을 확인하였다.

• Mass Spectrometry Letters
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• 제15권2호
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• pp.79 -94
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• 2024

Over the past few decades, new psychoactive substances (NPS) have become prevailing. With the widespread emergence of NPS, phenethylamines (PEAs) have become one of the groups abused most which PEAs, along with other stimulants, make up the majority of stimulants. When determining the NPS, the methods for screening and confirmation are crucial which assesses the reliability of testimony. In this study, a set of GC/MS methods employing two derivatizing agents for determining 76 target PEAs in urine was established and further applied for authentic sample analysis. Five PEAs (N,N-DMA, PMMA, 4-CA, amphetamine, and methamphetamine) with contents over their LLOQs were detected in thirteen of the twenty tested samples. In order to compare the result from the GC/MS methods with the previously established LC-MS/MS method, Cohen's kappa coefficient and McNemar's test were applied for statistical analysis. Perfect agreement between GC/MS and LC-MS/MS techniques for determining target PEAs is demonstrated by the Kappa coefficient for each of the five detected targets.

• 한국환경보건학회지
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• 제32권2호
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• pp.164-170
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• 2006

Ethylene oxide is a genotoxic carcinogen with widespread uses as industrial chemical intermediate and gaseous sterilant. 2-hydroxyethylated N-terminal valine in Hb is a good biomarker for biological monitoring of ethylene oxide exposure, because of its stability. For measuring the hemoglobin adduct formed by exposure of ethylene oxide, we studied the determination of (N-2-hydroxy-ethyl)valine(HEV) in hemoglobin adduct by using GC/MS. Firstly we synthesized HEV with 2-amino-ethanol and bromoisovaleric acid(BIVA) and confirmed it with GC/MS-FID. Its fragmentations were m/z 116(base ion, M+-45) and m/z 130(M+-31). For measuring HEV with higher sensitivity, we use derivatives which were PFPITH(pentafluorophenylisothiocianate) and TBDMS (tributyldimethylsilylation) by using Edman procedure. Its fragmentation were m/z 425(M+-57), m/z 383(M+-99) and m/z 172(M+-310) by using GC/MS. We did biological monitoring for mice inhalation exposure with 400 ppm ethylene oxide. The concentrations of hemoglobin adduct were $168{\pm}3.8\;and\;512{\pm}04$(nmol g-1 globin) at 0.5 hr/day 400 ppm ethylene oxide inhalation exposure group, and $631{\pm}17\;and\;2265{\pm}9.4$(nmol g-1 globin) at 1.0 hr/day 400 ppm ethylene oxide inhalation exposure for 1 and 4 weeks, respectively. We confirmed that (N-2-hydroxy-ethyl)valine(HEV) of hemoglobin was a good biomarker for biomonitoring of ethylene oxide exposure, and can measured with derivatives such as PFPITH(pentafluorophenylisothiocianate) and TBDMS(tributyldimethylsilylation) by using GC/MS.