• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.188-194
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• 2023

Microbacterium elymi KUDC0405^T was isolated from the rhizosphere of Elymus tsukushiensis from the Dokdo Islands. The KUDC0405^T strain was Gram-stain-positive, non-spore forming, non-motile, and facultatively anaerobic bacteria. Strain KUDC0405^T was a rod-shaped bacterium with size dimensions of 0.3-0.4 × 0.7-0.8 ㎛. Based on 16S rRNA gene sequences, KUDC0405^T was most closely related to Microbacterium bovistercoris NEAU-LLE^T (97.8%) and Microbacterium pseudoresistens CC-5209^T (97.6%). The dDDH (digital DNA-DNA hybridization) values between KUDC0405^T and M. bovistercoris NEAU-LLE^T and M. pseudoresistens CC-5209^T were below 17.3% and 17.5%, respectively. The ANI (average nucleotide identity) values among strains KUDC0405^T, M. bovistercoris NEAU-LLE^T, and M. pseudoresistens CC-5209^T were 86.6% and 80.7%, respectively. The AAI (average amino acid identity) values were 64.66% and 64.97%, respectively, between KUDC0405^T and its closest related type strains. The genome contained 3,596 CDCs, three rRNAs, 46 tRNAs, and three non-coding RNAs (ncRNAs). The genomic DNA GC content was 70.4%. The polar lipids included diphosphatydilglycerol, glycolipid, phosphatydilglycerol, and unknown phospholipid, and the major fatty acids were anteiso-C_17:0 and iso-C_16:0. Strain KUDC0405^T contained MK-12 as the major menaquinone. Based on genotypic, phylogenetic, and phenotypic properties, strain KUDC0405^T should be considered a novel species within the genus Microbacterium, for which we propose the name M. elymi sp. nov., and the type strain as KUDC0405^T (=KCTC 49411^T, =CGMCC1.18472^T).

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.420-429
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• 2023

GC-MS/MS using liquid-liquid extraction (LLE) and C18 cartridges was used to identify and quantify levels of chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin and permethrin in bulk raw milk. A calibration curve spanning 10 ng/mL to 200 ng/mL was obtained with a satisfactory correlation coefficient of 0.99. The limits of detection (LOD) and limits of quantitation (LOQ) for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in the matrix ranged from 0.06 to 1.81 ng/mL and 0.19 to 6.04 ng/mL, respectively. The recoveries of 5 pesticides from spiked samples at 37.5-125 ng/mL ranged from 86.1 to 102.1%. The measurement of uncertainty of the GC-MS/MS method for these five pesticides was developed based on the analytical process and quantification. An analysis method that is easier and faster than the method specified in the Korean food standards codes for analyzing these five pesticides in raw material milk was developed. Moreover, the analytical method for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in bulk raw milk by GC-MS/MS was established.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.80-88
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• 2002

휴대용 컴퓨터의 보급이 확산됨에 따라 이들을 장소에 상관없이 컴퓨터망에 연결시키는 수단으로 무선 LAN의 사용이 확산되고 있으나 무선 LAN 서비스는 전파라는 무선매체를 사용함으로써 정보도용의 가능성이 높으며 감시도 어렵다는 특징을 가지므로 정보보호가 요구된다. 본 논문에서는 IEEE 802.11 표준안 및 IEEE 802.lleS 초안에서 제시하는 무선 LAN의 정보보호기술인 ESN, WEP, AES 및 SMIB에 관하여 기술한다.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.15-15
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• 1996

In order to investigate the conformational preferences to elicit the tastes, conformational free energy calculations using the empirical potential ECEPP/3 and the hydration shell model were carried out on the L-aspartyl dipeptide methyl esters, L-$\^$+/HAsp$\^$-/-D-Xaa-OMe, in the unhydrated state, where Xaa includes sweet (Ala, Abu, Ser, Thr, Val, and lle), bitter (Phe, Trp, and Leu), and tasteless (Tyr and Met) residues. (omitted)

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.1
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• pp.91-118
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• 1999

Die vorliegende Arbeit behandelt ein zweidimensionales Valenzmodell. In diesem Modell wurde der Versuch unternommen, durch Beruck­sichtigung $valenzunabh\"{a}ngiger$ Faktoren die bisherige eindimensionale Valenzkonzeption zu $\"{u}berwinden\;und\;f\"{u}r\;Problemf\"{a}lle$ der Valenz­forschung angemessenere $Erkl\"{a}rungen$ zu bieten. Dabei wurde mit Agel (1994) davon ausgegangen, $da\ss$ man zwischen Valenzpotenz und Valenzrealisierung unterscheiden sollte. Zwischen den beiden Ebenen besteht keine Isomorphie. Auf der Ebene der Valenz­potenz spreche ich von valenzgebundenen und valenzfreien Gliedern, auf der Ebene der Valenzrealisierung dagegen von notwendigen und optional en Gliedern. Somit ergeben sich insgesamt vier $M\"{o}glichkeiten:$ 1. valenzgebunden und notwendig; 2. valenzgebunden und optional; 3. valenzfrei und notwendig; 4. valenzfrei und optional. Viele $Problemf\"{a}lle$ der bisherigen Valenzforschung $geh\"{o}ren$ zu dem zweiten und dem dritten Typ. Erst die Annahme des zweidimensionalen Valenzmodells bietet $daf\"{u}r\;systematische\;Erkl\"{a}rungen$. Anhand verschiedener Beispiele wurde gezeigt, $da\ss$ syntaktische, semantische, pragmatische und konzeptuelle Faktoren die Valenzrealisierung beeinflussen. Valenzrealisierung ist somit nicht als $blo{\ss}e$ Wiedergabe der im Lexikon immanenten Valenzpotenz anzusehen. $Schlie{\ss}lich$ wurde am Beispiel yon gehen das $Verh\"{a}ltnis$ zwischen Valenzpotenz, konzeptuellen Prozessen und Valenzrealisierung dargestellt: Die Realisierung der eigentlich valenzgebundenen lokalen Adverbial­bestimmung $h\"{a}ngt$ eng mit den konzeptuellen Prozessen ($Lokalisierungs-proze{\ss}\;vs.\;Delokalisierungsproze{\ss}$) zusammen. Falls $Lokalisierungs-proze{\ss}$ stattfindet, ist die Realisietung der lokalen Adverbialbestimmung notwendig, um die Direktionalisierung des Verweisobjekts im Hinblick auf das Bezugsobjekt zu bezeichnen. Bei $Delokalisierungsproze\ss$ ist die Realisierung der lokalen Adverbialbestimung dagegen optional.

• Analytical Science and Technology
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• v.23 no.6
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• pp.551-559
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• 2010

This study was conducted to establish an analytical method for the determination of seven nitrosamines in chlorinated tap water by precolumn derivatization followed by high performance liquid chromatography coupled with fluorescence detection. The derivatization procedure was optimized for denitrosation and dansylation, and then two extraction methods, liquid-liquid extraction (LLE) with dichloromethane and solid phase extraction (SPE), were compared. The SPE method employing the optimized derivation procedure showed higher extraction recovery (54.4-88.7%) and reproducibility (1.9-19.4%) than the LLE method (51.4-87.7% and 4.2-33.3%, respectively). The method detection limits were between 0.5 and 4.4 ng/L. When chlorinated water samples were collected from two treatment plants and ten household taps, and analyzed for nitrosamines, Nnitrosodimethylamine (NDMA) was the major compound found between 26.1 and 112 ng/L.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.559-568
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• 2003

A procedure based on liquid liquid extraction(LLE)-GC/MS has been developed for the simultaneous analysis of antioxidants and insecticides known as endocrine disrupters. The endocrine disrupters investigated in this study are butylated hydroxy anisole(BHA) and butylated hydroxy toluene(BHT), and the insecticides are allethrin and fenvalerate. The limit of detection(LOD) was 0.071~0.159 ng/ml with RSD of 1.41~5.34% for the standard sample. From water reservior of Han river, Geum river, Nakdong river and Sumjin river, these compounds were not detected. For the synthesized sample, the LOD is 0.051~0.132 ng/ml with RSD of 6.39~13.4%.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.71-76
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• 2020

While montelukast (ML), a cysteinyl-leukotriene type 1 receptor (CysLT1) antagonist is widely used to treat symptoms of rhinitis or asthma, its formulations are mainly limited to solid preparation due to its instability. Recently, there have been attempts to develop various ML dosage forms, and this situation increases the demand of sensitive and creditable methods to determine ML in various samples such as plasma. Thus, here, a simple and efficient method to determine ML in rat plasma using liquid-liquid extraction (LLE) and multiple reaction monitoring was presented. The mixture of DCM:EtOAc (25:75, v/v), the optimized extract solvent for LLE was found to be effective to extract ML without hydrophilic salts and proteins from the sample with limited volume. Also, the use of zafirlukast, instead of expensive ML-d6, as the internal standard makes the present method economical. The developed method was successfully validated in terms of selectivity, matrix effects (-14.8--6.9%), linearity (r230.998 within 0.5-500 ng/mL), sensitivity (the limit of detection and the lower limit of quantitation, ≤0.5 ng/mL), accuracy (88.4-100.6%), precision (3.0-13.3%), and recovery (80.8-86.3%) by following the FDA guidelines. Finally, the applicability of the validated method to pharmacokinetics (PK) studies was confirmed by the successful determination of PK parameters through it following oral administration of Singulair® granule in rats. Therefore, the present method can contribute to the development of new ML formulations through its performance to determine ML in rat plasma efficiently and sensitively.

• Mass Spectrometry Letters
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• v.12 no.1
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• pp.21-25
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• 2021

We aimed to develop and validate a sensitive analytical method of nannozinone A, active metabolite of Nannochelins A extracted from the Myxobacterium Nannocytis pusilla, in mouse plasma using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mouse plasma samples containing nannozinone A and 13C-caffeine (internal standard) were extracted using a liquid-liquid extraction (LLE) method with methyl tert-butyl ether. Standard calibration curves were linear in the concentration range of 1 - 1000 ng/mL (r2 > 0.998) with the inter- and intra-day accuracy and precision results less than 15%. LLE method gave results in the high and reproducible extraction recovery in the range of 78.00-81.08% with limited matrix effect in the range of 70.56-96.49%. The pharmacokinetics of nannozinone A after intravenous injection (5 mg/kg) and oral administration (30 mg/kg) of nannozinone A were investigated using the validated LC-MS/MS analysis of nannozinone A. The absolute oral bioavailability of nannozinone A was 8.82%. Plasma concentration of nannozinone A after the intravenous injection sharply decreased for 4 h but plasma concentration of orally administered nannozinone A showed fast distribution and slow elimination for 24 h. In conclusion, we successfully applied this newly developed sensitive LC-MS/MS analytical method of nannozinone A to the pharmacokinetic evaluation of this compound. This method can be useful for further studies on the pharmacokinetic optimization and evaluating the druggability of nannozinone A including its efficacy and toxicity.

• Analytical Science and Technology
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• v.22 no.1
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• pp.65-74
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• 2009

Active components of lacquer tree referred to as urushiol congeners, which are catechol derivatives with various alkyl or alkenyl substituents. The olefin side chains typically have one, two or three double bonds. In this study, the each congener's ratio analysis of extracts from korean lacquer tree are compared to the one from other asian lacquer tree. Extraction was performed using liquid-liquid extraction (LLE) method with soxhlet system from tree's bark and sap. Extracts were analyzed by reverse phase liquid chromatography and on-line electro spray ionization mass spectrometry (LC-MS/MS).