• Research in Plant Disease
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• v.12 no.2
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• pp.139-143
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• 2006

Virion captured reverse transcription polymerase chain reaction (VC/RT-PCR) could detect plant virus quickly and accurately. In the VC/RT-PCR, no antibody is needed unlike immuno-captured RT-PCR (IC/RT-PCR) which had been improved method of RT-PCR for plant viruses, and virus nucleic acids can be obtained easily within 30minutes by property of polypropylene PCR tube which is hold and immobilized viral particles on its surface. For the virion capture of Tomato spotted wilt virus (TSWV), the extraction buffer was tested. The optimum macerating buffer for TSWV was 0.01M potassium phosphate buffer, pH 7.0, containing 0.5% sodium sulfite. The viral crude sap was incubated for 30 min at $4^{\circ}C$. The virions in the PCR tubes were washed two times with 0.01M PBS containing 0.05% Tween-20. The washed virions were treated at $95^{\circ}C$ immediately for 1 min containing RNase free water and chilled quickly in the ice. Disclosed virions' RNAs by heat treatment were used for RT-PCR. Dilution end point of $10^{-5}$ from plant's crude sap infected with TSWV showed relatively higher detection sensitivity for VC/RT-PCR. During multiple detection using two or more primers, interference was arisen by interactions between primer-primer and plant species. The result of multiplex RT-PCR was influenced by combinations of primers and the kind of plant, and the optimum extraction buffer for the multiplex detection by VC/RT-PCR should be developed.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.353-359
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• 2000

Purpose: Although ${\alpha}$-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for ${\alpha}$-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for ${\alpha}$-fetoprotein (Riakey AFP IRMA $CT^R$, Sin-Jin Medics, Seoul, Korea). Materials and Methods: We evaluated intra- and inter-assay precision, recovery rate, parallelism, and sensitivity of serum ${\alpha}$-fetoprotein measurement using Riakey AFP IRMA $CT^R$ kit. The values of ${\alpha}$-fetoprotein measured by Riakey AFP IRMA $CT^R$ kit were compared with those measured by two foreign commercial kits (${\alpha}$-fetoproteina of Radim and ${\alpha}$-feto.riabead of Abbott). Results: Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within $100{\pm}10%$. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of ${\alpha}$-fetoprotein by Riakey AFP IRMA $CT^R$ and that by two foreign commercial kits(r=0.98). Conclusion: The first Korean domestic immunoradiometric kit for ${\alpha}$-fetoprotein, Riakey AFP IRMA $CT^R$, performed well for clinical use.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.163-177
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• 2013

An instrumented ferry made two transects per day across two current systems which are the North Korean Cold Current and the East Korean Warm Current over the years 2012-2013 from Gangneung to Ulleungdo in the southwestern East Sea. Seawater properties of these transects were measured with high spatial and temporal resolution for an extended period of time. Here the salinity records from the transects with the oceanographic observation data from East Sea Fisheries Institute of NFRDI, AVISO daily current chart and GOCI Chlorophyll-a image in 2012 and 2013 are used to study the time-series variation of salinity at the surface. The high salinity section with the range of 33.15~34.12 occurred on the transect mainly in the middle of eddy, and western boundary of strong northward current from June to October. We can found low salinity waters in both sides of the high salinity section. It is estimated that the western low salinity waters with the range of 30.58~33.20 accompanied by southward current were derived from the NKCC and the eastern waters with the range of 31.30~33.24 accompanied by northward current were derived from the Tsushima Surface Water. The lowest salinity of NKCC is confirmed in this study as 30.36. It is found that the western waters below 33.00 extended extremely toward the east about 110 km area from Gangneung and toward the south around Jukbyon coastal area as a 5~10 m layer. We can find its volume of low saline waters transport is not neglectable compared with that of Tsushima Current region in the western part of the East Sea. In this study we named it as the North Korean Low Saline Surface Water in summer.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.200-211
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• 2009

A mathematical modeling program called Soil and Water Assessment Tool (SWAT) developed by USDA was applied to Kyongan stream watershed. It was run under BASINS (Better Assessment Science for Integrating point and Non-point Sources) program, and the model was calibrated and validated using KTMDL monitoring data of 2004${\sim}$2008. The model efficiency of flow ranged from very good to fair in comparison between simulated and observed data and it was good in the water quality parameters like flow range. The model reliability and performance were within the expectation considering complexity of the watershed and pollutant sources. The results of pollutant loads estimation as yearly (2004${\sim}$2008), pollutant loadings from 2006 were higher than rest of year caused by high precipitation and flow. Average non-point source (NPS) pollution rates were 30.4%, 45.3%, 28.1% for SS, TN and TP respectably. The NPS pollutant loading for SS, TN and TP during the monsoon rainy season (June to September) was about 61.8${\sim}$88.7% of total NPS pollutant loading, and flow volume was also in a similar range. SS concentration depended on precipitation and pollution loading patterns, but TN and TP concentration was not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. SWAT based on BASINS was applied to the Kyongan stream watershed successfully without difficulty, and it was found that the model could be used conveniently to assess watershed characteristics and to estimate pollutant loading including point and non-point sources in watershed scale.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.9-18
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• 2009

The objectives of this study were to evaluate seasonal and interannual variations of water quality and nutrient input (N, P) in Junam Reservoir, a nesting waterbody of migratory birds, over 10 years during 1998$\sim$2007 along with dynamic relations of trophic parameters using empirical models. Concentrations of COD averaged 7.8 mg $L^{-1}$ during the study, while TN and TP were $1.4\;mg\;L^{-1}$ and $83{\mu}g\;L^{-1}$, respectively, indicating an eutrophic-hypereutrophic state. Values of monthly COD had strong positive relations (r=0.669, p<0.001) with conductivity, indicating that summer rainfall resulted in an ionic dilution of the reservoir water by rainwater and contributed better water quality. One-way ANOVA tests showed significant differences (F=$5.2{\sim}12.9$, p<0.05) in TN and TP between the before and after the bird migration. In other words, nutrient levels were greater in the absence of migratory birds than in the presence of the migratory birds, suggesting a no-effect on nutrient inputs by the birds. Also, one-way ANOVA indicated no significant differences (F=$0.37{\sim}0.48$, p>0.05) in $NO_{3^-}N$ and $NH_{3^-}N$ between the before and after the birds migration. Linear empirical models using trophic parameters showed that algal biomass as CHL, had significant low correlations with TN ($R^2$=0.143, p<0.001, n=119) and TP ($R^2$=0.192, p<0.001, n=119). These results suggest that influences of nutrients on the CHL were evident, but the effect was weak. This fact was supported by analysis of Trophic State Index Deviation (TSID). Over 70% in the observed values of "TSI (CHL)-TSI (SD)" and "TSI (CHL)-TSI (TP)" were less than zero, suggesting a light limitation on the CHL by inorganic suspended solids.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.354-374
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• 2016

This study explored spatiotemporal variability of water quality in correspondence with hydrometeorological factors in the five stations of Paldang Reservoir located in the Han River during 4 years from May 2012 to December 2015. Variability of basic water quality factors were largely related with seasonal fluctuations of hydrology. Temperature stratification occurred in the deep dam station, and prolonged hypoxia was observed during the draught year. Nitrogen nutrients were increased with decreasing inflow in which changing pattern of $NH_4$ reversed to $NO_3$ by the effect of treated wastewater effluent. Phosphorus increase was manifest during the period of high inflow or severe drought. Chl-a variation was reversely related with both flow change and AGP(algal growth potential) variations. Our study demonstrated that water quality variability in Paldang Reservoir was largely attributed to both natural and operational changes of inflow and outflow (including water intake) based on major pollution source of the treated wastewater (total amount of $472{\times}10^3m^3d^{-1}$) entering to the water system from watershed. In the process of water quality variability, meteorological (e.g., flood, typhoon, abnormal rainfall, scorching heat of summer) and hydrological factors (inflow and discharge) were likely to work dynamically with nutrients pulse, dilution, absorption, concentration and sedimentation. We underline comprehensive limnological study related to hydro-meteorolology to understand short- and long-term water quality variability in river-type large reservoir and suggest the necessity of P-free wastewater treatment for the effective measure of reducing pollution level of Paldang drinking water resource.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.327-333
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• 2014

A method for analysis of five artificial sweetners (sodium saccharin, aspartame, acesulfame-K, sucralose, cyclamate) in beverage samples was developed using high-performance liquid chromatography/triple quadrupole mass spectrometry (HPLC/MS/MS). The method uses a single-step dilution for sample preperation. Seperation was achieved on a $C_{18}$ column ($2.1{\times}150mm$, $3.5{\mu}m$) with A- 2% methanol (1 mM ammonium acetate), B-95% methanol (1 mM ammonium acetate) as mobile phase with gradient mode. The quantitation of target compounds was performed by external calibration in selected reaction monitorning (SRM) mode. The coefficient of determination of calibration curve for sodium saccharin, aspartame, acesulfame-K, sucralose and cyclamate were 0.9957, 0.9991, 0.9943, 0.9982 and 0.9948, respectively. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.001~0.022 mg/L and 0.004~0.073 mg/L, repectively. Recoveries for beverage samples were in the range of 92.76~113.50% with RSD < 10.91%. The method has applied to the determination of the five sweetners in 102 beverage samples. Three artificial sweetners-aspartame, acesulfame-K, sucralose were detected from 42 samples. Sodium saccharin and cyclamate were not detected in all samples.

• Korean journal of food and cookery science
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• v.25 no.4
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• pp.435-444
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• 2009

In this study, Paeonia japonica powder was extracted with ethanol, and its antimicrobial activity was investigated. The ethanol extract of the P. japonica had antimicrobial activity against Bacillus subtilis, Escherichia coli and Staphylococcus aureus. The inhibition zones of the P. japonica ethanol extract (3 mg/disc) against B. subtilis, E. coli and S. aureus were 10, 11, 8.5 mm, respectively. To test the food preservation effect of P. japonica and determine the optimal ratio of the P. japonica extract in the formulation, Sulgidduk samples were prepared with substitutions of 0, 0.25, 0.5, 0.75 and 1% P. japonica extract, and the quality characteristics of the samples were then investigated over 4 days of storage. In these experiments, total cell counts tended to decrease as the amount of added P. japonica extract increased. Moisture contents were not significantly different among the Sulgidduk samples. As the content of the P. japonica extract increased, the L-values of the samples decreased and the a- and b- values increased. In regards to the textural characteristics, the hardness, gumminess, and chewiness of the Sulgidduk samples decreased as the amount of P. japonica extract increased; however, they increased with the progression of storage time. Adhesiveness, springiness and cohesiveness were not significantly different at the different P. japonica extract concentrations and decreased with storage time. In the sensory evaluation, the control group had significantly higher scores for color, flavor and after taste as compared to the P. japonica extract added groups. When the P. japonica extract content was increased, the flavor and overall acceptability decreased, while Bakjakyak flavor, bitterness and off-flavor increased. Softness was not significantly different among the samples. In conclusion, the results indicate that substituting $0.25{\sim}1%$ P. japonica extract in Sulgidduk is optimal for quality and provides a product with reasonably high overall acceptability.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.497-503
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• 2012

This study was performed in order to evaluate the antioxidant activities of red beet extracts as well as the physicochemical properties and microbial changes of pork patties containing red beet during refrigerated storage. Red beet was extracted with water and ethanol. Red beet water extracts (RBW) and red beet ethanol extracts (RBE) were diluted with various concentrations (0.05~1.0%). DPPH radical scavenging activity and iron chelation activity of RBW showed a higher level than those of RBE (p<0.05). In particular, the iron chelation activity of RBW was over 53.4% at all levels. In addition, RBW at 1% had nearly 100% activity. On the other hand, the reducing powers of RBE were higher than those of RBW (p<0.05), and the antioxidant activity on linoleic acid emulsion of RBW was over 83% at all levels. Based on these model studies, 0.5% levels of RBW and RBE were added to ground pork patties (GPP), and the physicochemical properties and microbial changes of red beet GPP were evaluated during storage (0~14 d) at $4^{\circ}C$. The pH and microbial counts increased with increased storage time (p<0.05). Pork patties with BHT showed the lowest thiobarbituric acid reactive substances (TBARS) and microbial counts, and those with red beet had lower TBARS than the control (p<0.05). These results indicated that both red beet water and ethanol extracts could be used as natural antioxidants of pork patties during storage.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.977-983
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• 2002

This study was performed to establish the precise and rapid method to distinguish croakers through the pigment analysis of colored imported white croakers for adultration. We surveyed the coloring behaviors, extraction test by water and organic solvent and using pigments such as targeting, curcumine, and azo dye products. The pigment of yellow croaker is not stained on wet cloth or tissue which is rubbed on epidermis of yellow croaker and was not eluted in water extraction test, while adulterated pigments were easily extracted by water and acetone, but edible diluted yellow, Yellow No. 4 and Yellow No. 5 were not extracted. Reactive pigment was detected easily by extraction with water and dispersed pigment was also detected by extraction test. As a result of discoloring characteristics of carotene having similar structure to yellow croaker and azo dye by oxidation and reduction, azo dyes were not discolored by oxidation with sodium percarbonate or peracetic acid but that were discolored by oxidation with Fenton reagent after 1hr and by hypochlorite promptly. On the other hand, carotenes were not discolored by sodium precarbonate and Fenton reagent but discolored by sodium hypochlorite after 2 hr and by peracetic acid promptly. Azo dyes were discolored by reduction with sodium hydrosulfite and sodium carbonate but carotenes were not discolored by these reagents. This discoloring test was applicable to detect adulterated pigments and other marine product.