• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.35-39
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• 2005

Phosphor powders of zinc gal late added with Mg and rare-earth elements were prepared by sol id state reaction to improve luminescent properties. Green emitting $ZnMnGa_{2}O_{4}$ reached maximum intensity at Mn=0,005 mole$\%$ and further improvement was achieved by addition of $Mg^{2+}$. Tm, Mg-added zinc gallate phosphor exhibited a strong blue band emission, peaking at about 420 nm with the maximum intensity at the concentration of 0.003 mole$\%$ Mg and 0.015 mole$\%$ Tm. Deepening of the potential wells of the ground and excited states was suggested to be the cause for the enhancement in emission intensity at optimal doping of Mg and Tm.

• Journal of Species Research
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• v.13 no.1
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• pp.61-66
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• 2024

During an investigation of unrecorded prokaryotic species in Korea, six unrecorded bacterial strains were isolated from soil samples collected from Uljin-gun. Based on a similarity search using the 16S rRNA gene sequence of the isolated strains and the construction of the neighbor-joining phylogenetic tree, five strains were identified to the genus Pseudomonas of the family Pseudomonadaceae, while one strain was identified as a species belonging to the genus Paenibacillus of the family Paenibacillaceae. The details of these unreported species, including gram staining reaction, colony and cell morphology, basic biochemical characteristics, strain ID, and isolation source, are described in the description of the strains.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.984-991
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• 2008

This paper reports experimental results, demonstrating the feasibility of horseradish peroxidase(HRP) and H$_2$O$_2$ to reduce phenol transport in saturated porous media. A laboratory-scale packed column reactor(ID: 4.1 cm, sand-bed height 12 cm) column was utilized to simulate injection of HRP and H$_2$O$_2$ into an aquifer contaminated with phenol. Effluent concentrations of phenol and polymerization products were monitored before and after enzyme addition under various experimental conditions(enzyme dose: 0$\sim$2 AU/mL, [ionic strength]: 5$\sim$100 mM, pH: 5$\sim$9). The concentration of phenol in the column effluent was found to decrease by nearly 90% in the presence of HRP(2 AU/mL) and H$_2$O$_2$ in the continuous flow system at pH 7 and ionic strength 20 mM. The influent phenol was converted in the system to insoluble precipitate, which deposited in pore spaces. The remains were discharged as soluble oligomers. About 8% of total pore volume in column system was decreased by deposition of polymer produced.

• The Korea Journal of Herbology
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• v.23 no.1
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• pp.117-125
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• 2008

Objectives : This study was to verify the Attributive Channel theory of herbal medicine. Methods : [$^{131}I$]iodohesperetin was synthesized, separated, and refined from hesperetin, the major component of Citrus species, followed by observing the biodistribution in an organism of C57 BL/6 mice with and without Lewis Lung Carcinoma. Results : Iodohesperetin 27.5 mg was obtained through column cliromatography after a reaction with 50 mg of Hesperitin and 8 mg of Nal. The radiochemical yield of [$^{131}I$]iodohesperetin synthesis was 25 % when checked with Radio TLC chromatography. [131I]iodohesperetin was most largely distributed in the stomach, lung and liver of C57BL/6 mouse. The highest %ID/g in stomach was 40 min, in lung and liver was 20 min after injection. The % ID/g of tumor tissue was comparable with that of blood. Conclusions : The fact that [$^{131}I$]iodocurcumin was most largely distributed in the stomach, lung and liver was related with the Attributive Channel theory. And there was no significant finding related to tumor cells.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.21-27
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• 2016

The objectives of this study are to produce monoclonal antibodies (MAbs) against Vibrio parahaemolyticus and to develop an immuno-selective filtration (ISF) method for the rapid and sensitive detection of V. parahaemolyticus. The characterization of the MAb produced from HKVP 4H9-9 hybridoma cell was validated by enzyme-linked immunosorbent assay (ELISA) and western blot. The produced MAb was specific to V. parahaemolyticus and showed weak cross-reaction to V. alginolyticus, V. vulnificus and Staphylococcus aureus. After optimization of the method, $5{\times}10^1cell/mL$ of V. parahaemolyticus in a pure culture could be detectable. Although weak cross-reactivity to V. vulnificus, V. alginolyticus and Staphylococcus aureus was observed, the ISF was confirmed to be highly specific to V. parahaemolyticus. Especially, the ISF showed the most sensitivity compared to the immunoassays currently reported is easier to perform and quicker than ID-ELISA.

• Analytical Science and Technology
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• v.28 no.6
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• pp.460-466
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• 2015

An isotope dilution liquid chromatography tandem mass spectrometry was developed as a primary method for the quantitative analysis of cholesterol in infant formula. Cholesterol-d₄ was used as an internal standard and spiked into the infant formula sample. In order to release cholesterol out of cholesteryl ester, which is cholesterol bound to fatty acids in infant formula, saponification was carried out. Saponification conditions were optimized with heating temperature, reaction time and the concentration of KOH. The optimum conditions were as follows; heating temperature was 70 ℃, reaction time was 180 min and the concentration of KOH was 0.8 mL of 8 M KOH for about 0.1 g infant formula sample. Extraction of cholesterol out of sample solution was carried out with hexane uisng liquid-liquid extraction. Chromatographic analysis was carried out using Phenomenex Kinetex C₁₈ column. Mobile phase was 0.1% acetic acid in methanol/water (v/v, 99/1) and flow rate was 0.3 mL/min. Cholesterol and cholesterol-d₄ were monitored at mass transfer m/z 369/259 and 373/263 respectively. Reproducibility of the method was evaluated to be 0.23% of the measurement result. The expanded uncertainty of the measurement result of cholesterol in infant formula was approximately 1.9% at a 95% confidence level. NIST standard reference material having certified values of cholesterol in infant formula, was analyzed in order to verify this method. The ID-LC/MS/MS results were well agreed with the certified values of NIST SRM within the uncertainty.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.318-322
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• 1988

We studied the aquation reaction of s-cis-$[Co(eee)Cl_2]^+$ and s-cis-$[Co(eee)Br_2]^+$ complex ions under the various temperatures and pressures. In these complexes eee is $NH_2-CH_2CH_2-S-CH_2CH_2-NH_2$. The rate law of the aquation reactions of these two complexes obeys $Rate = k_{obsd}$[CO(III)], where rate constants of s-cis-$Co(eee)Cl_2]^+$ and s-cis-$[Co(eee)Br_2]^+$ respectively are $0.687{\times}10^{-4}$ $sec^{-1}$ and $4.10{\times}10^{-4}$ $sec^{-1}$ in condition of 0.1M $HClO_4\;and\;40^{\circ}C$. In the same condition, the activation entropies of s-cis-[Co(eee)$Cl_2$]+ and s-cis-(Co(eee)Br_2$]+ complexes respectively are -15.5 eu and -7.54eu, and the activation volumes are $-4.6cm^3mole^{-1}$ and $-4.2cm^3mole^{-1}$. From these data, we could infer the mechanism of the aquation reaction as the interchange dissociation (Id) mechanism.

• Analytical Science and Technology
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• v.31 no.6
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• pp.225-231
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• 2018

Benzoic acid, methyl paraben, and butyl paraben are preservatives that have been used in pharmaceutical, cosmetic, and food products. However, as their toxicities for human have been reported, many nations and organizations including Korea have established a regulation limit for thier usage of these preservatives in food products. The present study developed the isotope dilution liquid chromatography mass spectrometry method for accurate determination of three target preseratives in soysauce. In this study, the isotope dilution liquid chromatography mass spectrometry method was developed for accurate determination of three target preservatives in soy sauce. LC separation was optimized considering the pKa of benzoic acid which is lower than those of methyl and butyl parabens. A C18 column was used with 5 mM ammonium acetate and methanol as mobile phases. Mass spectrometry was operated in negative mode and selected reaction monitoring mode (SRM). Soy sauce sample was cleaned-up with C18 SPE cartridge for removing matrix inferences and color material. Optimized conditions and the method were validated with soy sauce reference materials for the analysis of food preservatives from Health Science Authority in Singapore. The measured values of benzoic acid, methyl and butyl paraben agreed well with reference values within their uncertainties.

• Membrane Journal
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• v.9 no.3
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• pp.157-162
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• 1999

In the crosslining reaction of poly(vinyl alcohoJ)(PVA) with sulfur-succinic acid which had been established in our previous work, reaction temperature, 15$0^{\circ}C$, was so high to collapse the pore struc¬tures in support membrane for the preparation of composite membrane. Therefore, the efforts have been focused on lowering of the reaction temperature to 100$^{\circ}$C by using a catalysis, HC!. The newly established crosslinking reaction was characterized through the analysis of the chemical and thermal properties. From these results, the optimum conditions for the membrane preparation couId be drawn as followings : (i) reac¬tion temperature, 100 $^{\circ}C$,(ii) reaction time, 90 min, (iii) the concentration of the catalysis (HCD, 1.5%. Com¬posite membranes were fabricated by coating a casting solution containing PYA, sulfur-succinic acid and HCl on a support membrane followed by crosslinking it at 10$0^{\circ}C$. The resulting membranes were applied to the pervaporation separation of methyl-tert-butyl ether(MTBE)/methanol (MeOH) mixtures at 30, 40, and 5O$^{\circ}C$. The flux of 5.09 g/$m^2$hr at 5O$^{\circ}C$ and the highest separation factor of 1622 were obtained, respectively.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.471-475
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• 1998

The aim of the present research program was to develop a strain of gastrointestinal bacteria containing antitumor substances. Fecal samples were collected from neonates and a number of gastrointestinal bacteria were isolated from the fecal samples by applying selective agar for intestinal bacteria. Among 127 isolates, a strain 2B4-1 containing an antitumor substance against stomach cancer, SNU-1, was selected. The strain 2B4-1 was identified as a strain similar to Enterococcus faecalis NCTC 775 with respect to morphological characteristics, growth temperature, salt and acid tolerance, growth under facultative anaerobic conditions and utilization of carbon sources such as arabinose and melibiose and so on. However, it showed some differences such as a negative reaction to hippurate hydrolysis and negative reaction to $\beta$-hemolysis. We assigned to the strain 2B4-1 to Enterococcus faecalis.