• 통합자연과학논문집
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• 제9권2호
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• pp.121-127
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• 2016

CXC chemokine receptor 2 (CXCR2) is a prominent chemokine receptor on neutrophils. The neutrophilic inflammation in the lung diseases is found to be largely regulated through CXCR2 receptor. Antagonist of CXCR2 may reduce the neutrophil chemotaxis and alter the inflammatory response. Hence, in the present study, ligand based Comparative molecular field analysis (CoMFA) was performed on a series of CXCR2 antagonist named pyrimidine-5-carbonitrile-6-alkyl derivatives. The optimum CoMFA model was obtained with statistically significant cross-validated coefficients ($q^2$) of 0.568 and conventional coefficients ($r^2$) of 0.975. The contour maps suggest the important structural modifications and this study can be used to guide the development of potent CXCR2 antagonist.

• 분석과학
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• 제16권6호
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• pp.509-512
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• 2003

Pretreatment method for the determination of total arsenic in seafood sample was studied. NIST SRM 1566a oyster tissue ($14.0{\pm}1.2mg\;As/kg$) as a standard arsenic compound in order to establish the decomposition method. We confirmed that the best way for pretreatment of seafoods to analyze total arsenic content precisely was $HNO_3-H_2SO_4-HCIO_4$ method by comparison of two methods which are dry ashing and wet ashing methods.

• Journal of Power Electronics
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• 제5권3호
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• pp.240-246
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• 2005

Considering the start-up and economical efficiency, the optical sensor technique using a slotted-disk and an opto-interrupter are appropriate, however, this method needs three opto-interrupters and a slotted-disk when driving the 6/4 pole SRM(switched reluctance motor). In this paper, we propose an economic method by replacing the conventional opto-interrupter and slotted-disk with only optical sensor which enables the motor to start up and forward and reverse operation. Also the control circuit includes only analog devices, which makes the process more economical.

• 분석과학
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• 제10권6호
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• pp.439-444
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• 1997

압전 세라믹스 [$Pb(ZrTi)O_3$] 소재에 대하여 신속하고 정확하게 분석할 수 있는 X-선 형광분석용 표준물질 12종을 제작하였다. 특히 매질효과의 제거, 보관성, 균질성 등을 고려하여 융제($Li_2B_4O_7/LiBO_2=4/1$)로 시료를 16배 희석하여 제작하였다. 네 곳의 분석기관에서 X-선 형광분광기로 12개의 표준물질에 포함된 11 원소에 대하여 검정곡선을 작성해 본 결과 PbO, $ZrO_2$, $TiO_2$, SrO, $WO_3$, $La_2O_3$, $Cr_2O_3$, MgO, $Nb_2O_5$, $MnO_2$들은 correlation factor가 0.998을 넘는 대단히 좋은 직선을 얻었다. 그러나 ZnO의 correlation factor는 0.977로 비교적 낮았으며, 이는 표준시료 중 ZnO의 함량이 10ppm 정도로 낮았기 때문이다. 본 연구에서 제작한 XRF 분석용 표준물질을 이용하면 PZT 중의 주 부성분 원소의 함량을 간편하고 신속 정확하게 분석결과를 얻을 수 있다.

• 환경영향평가
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• 제27권5호
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• pp.405-416
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• 2018

대기 중 입자상 물질에 대한 자동차 오염원의 지표원소로서 백금족 원소 (Platinum Group Elements, PGEs)에 대한 분석법의 유효성을 검증하고, 도로변 먼지 중 PGEs의 분포 특성을 평가하였다. 인증표준물질을 이용한 유효성 평가 결과, Pt, Pd, Rh의 상대오차는 각각 -0.7%, -10.0%, -20.4%이고 상대표준편차는 Pt, Pd, Rh 모두 10% 미만으로 반복 분석에 따른 재현성이 우수한 것으로 나타났다. 연구대상지역에서 채취한 도로변 먼지 시료 중 Pt, Pd, Rh의 농도는 각각 $17.4{\pm}9.2{\mu}g/kg$, $283.6{\pm}20.5{\mu}g/kg$, $7.3{\pm}2.8{\mu}g/kg$으로 Pd의 농도가 가장 높았다. Pt와 Rh의 농도는 배경지역이나 일반 도시지역의 토양 내 농도에 비해 지하주차장과 도로변 지역의 먼지에서 평균 농도가 상당히 높았고, 이러한 평균농도의 차이는 통계적으로 유의한 것으로 나타났다. 또한, 도로변 먼지에서의 PGEs의 농도 간 상관분석결과, Pd 보다는 Pt와 Rh가 자동차 오염원의 영향을 민감하게 반영하는 것으로 나타났다.

• 한국축산식품학회지
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• 제34권6호
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• pp.749-756
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• 2014

A rapid and simple analytical method for L-carnitine was developed for infant and toddler formulas by liquid chromatography tandem mass spectrometry (LC-MS/MS). A 0.3 g of infant formula and toddler formula sample was mixed in a 50 mL conical tube with 9 mL water and 1 mL 0.1 M hydrochloric acid (HCl) to chemical extraction. Then, chloroform was used for removing a lipid fraction. After centrifuged, L-carnitine was separated and quantified using LC-MS/MS with electrospray ionization (ESI) mode. The precursor ion for L-carnitine was m/z 162, and product ions were m/z 103 (quantitative) and m/z 85 (qualitative), respectively. The results for spiked recovery test were in the range of 93.18-95.64% and the result for certified reference material (SRM 1849a) was within the range of the certificated values. This method could be implemented in many laboratories that require time and labor saving.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1976-1980
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• 2010

A simple and reliable method has been developed to selectively separate and concentrate trace amounts of Fe(III) ions from water and food samples by using flame atomic absorption spectrometry. A new reagent, 5-hydroxy-4-ethyl-5,6-di-pyridin-2-yl-4,5-dihydro-2H-[1,2,4] triazine-3-thione, was synthesized and characterized by using FT-IR spectroscopy and elemental analysis. Effects of pH, concentration and volume of elution solution, sample flow rate, sample volume and interfering ions on the recovery of Fe(III) were investigated. The optimum pH was found to be 5. Eluent for quantitative elution was 10 mL of 2 M HCl. The preconcentration factor of the method, detection limit (3s/b, ${\mu}gL^{-1}$) and relative standard deviation values were found to be 25, 4.59 and 1%, respectively. In order to verify the accuracy of the method, two certified reference materials (TMDA 54.4 lake water and SRM 1568a rice flour) were analyzed. The results obtained were in good agreement with the certified values. The method was successfully applied to the determination of Fe(III) ions in water and food samples.

• 한국연초학회지
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• 제28권1호
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• pp.51-57
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• 2006

This study was carried out to improve and evaluate the analytical method for determination of potassium in tobacco leaf by various pre-treatment techniques. The time requirment of various pre-treatments was about 10 hour for dry ashing and 6 hour for microwave digestion and 3 hour for sonication. The results of recover in both pre-treatment techniques, microwave digestion and sonication, is greater than 85 % stably with reproducibility(RSD %) on replicates of less than 3 %. However the mean values for microwave digestion were lower than certified standard value of NlST SRM. Compared to the other pre-treatment techniques, analytical results for sonication technique strictly improved the accuracy and precision. In conclusion, the use of the simple sonication technique seems to be efficient for the determination of potassium in tobacco leaf in consideration for both the accuracy and reproducibility.

• 통합자연과학논문집
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• 제7권4호
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• pp.241-252
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• 2014

A series of N-benzoylated ligands incorporating three different benzoyl groups 2,2'-(benzoyliminodiethylene)-4-substituted phenols ($L^{1,4,7}$), 2,2'-(4-nitrobenzoyliminodiethylene)-4-substituted phenols ($L^{2,5,8}$) and 2,2'-(3,5-dinitrobenzoyliminodiethylene)-4-substituted phenols ($L^{3,6,9}$) were synthesized and characterized by IR, $^1H$ NMR, $^{13}C$ NMR and mass spectroscopy. The In vitro antibacterial activity of investigated ligands were tested against human pathogenic bacteria such as four Gram (-) Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Vibrio cholera, Vibrio harveyi and two Gram (+) Staphylococcus aureus, Streptococcus mutans. Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the binding site of the topoisomerase II (PDB: 4FM9) enzyme which is involved in DNA superhelicity and chromosome seggregation. The N-benzoylated derivatives $L^{5,7,8}$ have significant anticancer activity as Topoisomerase inhibitors. The ligands $L^5$ and $L^8$ were tested for their anticancer activity against human liver adenocarcinoma (HepG2) cell line with the MTT assay.

• 한국식품영양과학회지
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• 제44권3호
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• pp.418-424
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• 2015

본 연구는 식품성분표 개정을 위한 기초연구로서 농산식품인 조미료류 5개, 차류 2개, 채소류 2개, 곡류 3개, 견과류 및 종실류 6개, 유지류 2개, 과일류 20개에 함유되어 있는 기능성 영양성분 중 하나인 베타카로틴 함량을 분석하였다. 대표성과 신뢰성이 확보된 베타카로틴의 분석품질을 확보하기 위하여 참값을 알고 있는 표준인증물질인 slurried spinach(SRM 2385)의 베타카로틴 함량을 측정한 결과 RSD 1.73%였으며, 회수율은 102%로 아주 양호한 결과를 얻었다. 농산식품 분석 결과 채소류와 차류에서 비교적 높은 베타카로틴 함량이 검출되었다. 보리순가루 $17,293.95{\mu}g/100g$($2,882.33{\mu}gRE$), 보리순 생것 $2,755.15{\mu}g/100g$($459.19{\mu}gRE$), 녹차가루 $7,579.04{\mu}g/100g$($1,263.17{\mu}gRE$), 마른 녹차잎 $13,671.85{\mu}g/100g$($2,278.64{\mu}gRE$)으로 베타카로틴 함량이 비교적 높았다. 견과류 및 종실류의 베타카로틴 함량 분석 결과 검은 참깨 마른 것 $41.27{\mu}g/100g$($6.88{\mu}gRE$), 들깨 마른 것 $33.06{\mu}g/100g$($5.51{\mu}gRE$), 흰 참깨 마른 것 $25.36{\mu}g/100g$($4.23{\mu}gRE$) 순으로 베타카로틴 함량이 검출되었다. 유지류의 베타카로틴 함량 분석 결과 들기름 $58.56{\mu}g/100g$($9.76{\mu}gRE$)과 참기름 $11.41{\mu}g/100g$($1.90{\mu}gRE$)으로 측정되었다. 과일류 20개에서는 살구 생것 $2,280.35{\mu}g/100g$($380.06{\mu}gRE$)과 파파야완숙 생것 $242.57{\mu}g/100g$($40.43{\mu}gRE$), 파파야적숙 생것 $162.70{\mu}g/100g$($27.12{\mu}gRE$)으로 비교적 높은 베타카로틴 함량을 나타내었다. 거봉 생것, 청포도 생것, 켐벨얼리포도 생것의 경우 껍질을 포함하였을 때 베타카로틴 함량이 높게 측정되었다.