• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.228-235
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• 2012

A $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine (4-$CH_3O$-salphen) was synthesized. Using the 4-$CH_3O$-salphen, the spectrophoto-metric quantitative analysis of Cu(II) ion in aqueous solution was performed. The optimum condition for the quantitative analysis of Cu(II) ion was determined as the following; the concentration of 4-$CH_3O$-salphen is $2.0{\times}10^{-4}\;mol/L$, ratio between solvent DMSO and water is 50/50(v/v), pH is 5.5. After 1 hr water incubation at $55^{\circ}C$ and then the absorbance measurements at 388 nm, a calibration curve (${\varepsilon}=3.6{\times}10^4\;mol^{-1}cm^{-1}$) with a correlation coefficient ($R^2$=0.9963) was obtained in this condition. Using this optimized condition, the quantitative analysis of Cu(II) ion was performed with various samples such as hot spring water, semiconductor factory waste water and treated water from sewage treatment plant. The average value of the measured values agreed well with standard value with a range of 0.6~5.4%. The limit of determination was 31.77 ng/mL ($5.0{\times}10^{-7}\;mol/L$).

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.8
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• pp.952-956
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• 2017

An high performance liquid chromatography (HPLC) analysis method was developed for standard determination of coixol as a functional cosmetic material in Coix lachryma-jobi var. ma-yuen roots extract. HPLC was performed on a $C_{18}$ Unison US column ($4.6{\times}250mm$, $5{\mu}m$ column) using a gradient elution of 0.1% (v/v) trifluoroacetic acid and acetonitrile at a flow rate of 1.0 mL/min at $30^{\circ}C$. The analyte was detected at 290 nm. The HPLC method was validated in accordance with the International Conference on Harmonization guideline of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limit of detection and quantitation were 0.07 and 0.25 mg/mL, respectively. Calibration curves showed good linearity ($R^2$>0.9995), and the precision of analysis was satisfied (less than 0.29%). Recoveries of quantified compounds ranged from 98.36 to 100.30%. This result indicates that the established HPLC method is very useful for the determination of a marker compound in C. lachryma-jobi var. ma-yuen roots extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1737-1741
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• 2014

An HPLC method for determination of naringin was developed to standardize it as a marker compound in Goheung yuzu extract as a functional health food. Optimum results were obtained by C-18 column chromatography using solvent mixtures (A: 0.5% acetic acid, B: acetonitrile) as the stationary phase and mobile phase. The method was fully validated and sensitive with a limit of detection (LOD) of 0.0218 mg/L and limit of quantification (LOQ) of 0.0661 mg/L. The method showed high linearity (coefficient of correlation=0.9986) and high accuracy, as recovery rates of naringin at concentrations of 1, 0.5, 0.1, 0.05 mg/mL were in the ranges of 95.74~98.25%, 97.67~101.01%, 97.33~104.64%, and 95.53~106.82%, respectively. Intra-day and inter-day variation, which are measures of method precision, were 1.39~1.95% and 0.17~1.49%, respectively. Therefore, the method could be used without modification for determination of naringin as a marker compound in Goheung yuzu extracts.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.16-26
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• 2017

In chemical industry plants, the raw material, intermediate and final products can leak from unstable joints of flanges and valves as well as cracks of storage tanks. From the safety and economic standpoints, it is very important to understand whether leaks or not and leakage rate. The OGI(optical gas image) technique can tell gas leakages, but cannot give the leakage rate. Some special OGI devices can show the kind of gas in different color concentration in different darkness. Therefore the research on quantification of OGI is necessary. In this research, we have developed the practical method to quantify OGI of methane leakage. To estimate 3-dimensional gas leakages distribution from 2-dimensional OGI, the Monte Carlo Probability technique was applied. First the number of points in the area of width(2.54 cm) and length(2.54 cm) in OGI was counted. Total no of each experiment was compared with the measured flow rate. The correlation average between total points and measured flow rate was found to be 0.980. Reversely we estimated the leakage rate of OGI by use of the correlation table. The results showed good agreement between the estimation value and the measured value.

• Journal of Conservation Science
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• v.32 no.3
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• pp.425-436
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• 2016

The Yakhyeon catholic church (Historic Site No. 252 in Korea) that was constructed in 1892 has been the first western brick structure to ever have existed and one of the most important historical materials in the Korean modern architecture. After a fire had broken out at the catholic church in 1998, the stained glass on the back wall, the slab glass (dalle de verre) introduced by Lee Nam Guy in 1974, was repaired in 1999 because of singe scorch and water leakage. An analysis of the coloration elements showed that yellow, red and green included Zn, K and Cd, respectively. The glass of red contained Se, dark green contained Mn and Cr, and blue contained Pb and S. According to material analysis, the masonry joint was identified dolomite ($CaMg(CO_3)_2$) and calcite ($CaCO_3$), which was observed plate, columnar, rhombic and square of crystalline particles. Meanwhile, ultrasonic velocity in the stained glass recorded low speed in the middle and lower right of the window (an average of 4,130 m/s). And the joint was measured the lowest physical properties of the top left and middle of the window (an average of 2,053 m/s). This study have showed that extensive physical damage was founded to the left and middle rather than the right side. In this respect, more research in needed to conserve the correlation between color and physical properties.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.34-39
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• 2006

Wood-rot fungi produce extracellular lignin-degrading enzymes, the best known of which are lignin peroxidase, Mn-peroxidase and laccase. In this experiment, some of them produced all of three enzymes. Many other wood-rot fungi produced one or two of those enzymes with various combinations. In this experiment, we tried to clarify the relationship between the pattern of enzyme production and degradative activity of several dye compounds. From the 36 strains of 23 species of wood-rot fungi, Mn-peroxidase activity was found in 30 strains of the fungi tested, whereas the activity of lignin peroxidase and laccase was detected in 11 strains and 12 strains of species, repectively, in Kirks low nitrogen media. In relation to the activity of lignin degrading enzymes and degradation of dye compounds, the white-rot fungi with three kinds of enzymes tested showed the best dye decolorizers. The fungi with Mn-peroxidase activity only decolorized poly R-478 and remazol brilliant blue R dye in proportion to the enzyme activity, while methylene blue, bromophenol blue and congo red dye were degraded in regardless of enzyme activity. Those dyes were degraded in relation to the growth rate of mycelium. Brown-rot fungi did not degrade all the dye compounds except bromophenol blue, in spite of moderate growth rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.244-248
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• 2013

We studied the development of schizandrin as a marker compound in Jangsu Omija. Schizandrin was validated for its LOD (limit of detection), LOQ (limit of quantitation), precision, accuracy, and recovery by HPLC relative to Omija powder. It showed a high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9990. The LOD and LOQ were 0.2 ${\mu}g/mL$ and 0.5 ${\mu}g/mL$, respectively. The intra- and inter-day precision of schizandrin calibration standards was 0.06~0.66% and 0.13~1.19%, respectively, and the intra- and inter-day accuracy of schizandrin was 98.35~103.30% and 98.35~103.00%, respectively. Overall, schizandrin was validated through our analytical methods as a marker compound in Jangsu Omija.

• Food Science and Preservation
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• v.13 no.2
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• pp.154-160
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• 2006

Shelf-life of functional beverage for the purpose of body fat reduction during storage was estimated at different temperatures. To estimate quality change of functional beverage, vacuum gauge, sugar concentration pit acidify, Hunter's color value, browning color intensity, total cell count and sensory evaluation were measured periodically. Vacuum gauge, sugar concentration pH and acidity were little changed and total cell count was not detected. By using the correlation coefficient between sensory evaluation and physicochemical properties, b-value was chosen for quality index of functional beverage. $Q_{10}-values$ for shelf-life were in the range of $2.13{\sim}2.59$. When sensory evaluation was 2.5 at $50^{\circ}C$, storage period was 6.83 weeks. And shelf-life calculated by $Q_{10}-values$ were 73.89, 34.21 and 13.21 weeks in $20^{\circ}C,\;30^{\circ}C\;and\;40^{\circ}C$, respectively.

• Development and Reproduction
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• v.16 no.2
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• pp.95-100
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• 2012

Bisphenol A (BPA), a chemical with weak estrogenic activity is reported to affect preimplantation embryos, fetuses and alter their postnatal development. This study amied to determine the relation between the levels of BPA in the amniotic fluid and pregnancy outcomes. ELISA was used to measure amniotic fluid BPA in 120 pregnant women who underwent genetic amniocentesis at 15~20 weeks gestation. The most common indication for amniocentesis was advanced maternal age (35 yrs or older). BPA was detected in all amniotic fluid. The range of amniotic fluid BPA concentrations was from 0.89 ng/mL to 37.13 ng/mL with a mean level of 7.24 ng/mL. We compared the means of amniotic fluid BPA concentrations according to maternal age (${\geq}35$ vs. <35 yrs), fetal sex (male vs. female), gestational age at birth (${\geq}37$ vs. <37 weeks), and infant birth weight (${\geq}2.5$ vs. <2.5 kg). No significant differences were found in these outcomes. This is the first report of amniotic fluid BPA levels in Korean pregnant women. Our findings suggest that BPA may not affect the pregnancy outcomes such as fetal sex, preterm delivery and low birth weight. Whether prenatal exposure to BPA can have teratogenic effect on developing embryo needs to be studied.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.105-111
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• 2009

Norovirus (NV) with a variety of genotypes, a member of the family Caliciviridae, causes acute nonbacterial gastroenteritis in humans. We determined the nucleotide sequence of three open reading frames (ORFs) of a NV Korean strain and characterized the genetic relationship with others. The Korean strain designated Hu/NLV/Gunpo/2006/KO was isolated from the stool specimen of a 2-year-old female suffering from gastroenteritis. By performing reverse transcription and PCR amplification, three overlapping cDNAs were synthesized and used for direct sequencing. We found that like other NVs, this strain contains three ORFs: ORF1, 5,100 bp; ORF2, 1,647 bp; ORF3, 765 bp. Of 35 NVs, ORF1 had a level of genetic diversity lower than ORF2 and ORF3, of which the C-termini of the ORF2 and ORF3 showed a relatively high degree of genetic diversity. Phylogenetic analyses indicated that the Korean strain belonged to genogroup II, with Saitama U1, Gifu'96, Mc37, and Vietnam 026 being formed a single genetic cluster. The nucleotide sequence information of three ORFs of a NV Korean isolate will be useful not only for the development of a diagnostic tool and understanding of genetic relationship, but also provide important basic information for the functional analysis of their gene products.