• Journal of Food Hygiene and Safety
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• v.30 no.3
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• pp.272-280
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• 2015

A simultaneous official method was developed for the determination of phorate and its metabolites (phorate sulfoxide, phorate sulfone, phorate oxon, phorate oxon sulfoxide, phorate oxon sulfone) in livestock samples. The analytes were quantified and confirmed via liquid chromatograph-tandem mass spectrometer (LC-MS/MS) in positive ion mode using multiple reaction monitoring (MRM). Phorate and its metabolites were extracted from beef and milk samples with acidified acetonitrile (containing 1% acetic acid) and partitioned with anhydrous magnesium sulfate. Then, the extract was purified through primary secondary amine (PSA) and C18 dispersive sorbent. Matrix matched calibration curves were linear over the calibration ranges (0.005-0.5 mg/L) for all the analytes into blank extract with $r^2$ > 0.996. For validation purposes, recovery studies were carried out at three different concentration levels (beef 0.004, 0.04 and 0.2 mg/kg; milk 0.008, 0.04 and 0.2 mg/kg, n = 5). The recoveries were within 79.2-113.9% with relative standard deviations (RSDs) less than 19.2% for all analytes. All values were consistent with the criteria ranges requested in the Codex guidelines. The limit of quantification was quite lower than the maximum residue limit (MRL) set by the Ministry of Food and Drug Safety (0.05 mg/kg). The proposed analytical method was accurate, effective and sensitive for phorate and its metabolites determination and it will be used to as an official analytical method in Korea.

• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.123-130
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• 2014

A simultaneous determination was developed for 9 aminoglycoside antibiotics (amikacin, apramycin, dihydrostreptomycin, gentamicin, hygromycin B, kanamycin, neomycin, spectinomycin, and streptomycin) in meat by liquid chromatography tandem mass spectrometry (LC-MS/MS). Each parameter was established by multiple reaction monitoring in positive ion mode. The developed method was validated for specificity, linearity, accuracy, and precision based on CODEX validation guideline. Linearity was over 0.98 with calibration curves of the mixed standards. Recovery of 9 aminoglycosides ranged on 60.5~114% for beef, 60.1~112% for pork and 63.8~131% for chicken. The limit of detection (LOD) and limit of quantification (LOQ) were 0.001~0.009 mg/kg and 0.006~0.03 mg/kg, respectively in livestock products including beef, pork and chicken. This study also performed survey of residual aminoglycoside antibiotics for 193 samples of beef, pork and chicken collected from 9 cities in Korea. Aminoglycosides were not found in any of the samples.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.124-130
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• 2018

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for the use of health functional foods (dietary food supplement), in order to establish regulatory standards and specifications in Korea. In this regard, we continue to pursue and perform our research on the analytical method development for the items being researched and reviewed. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determinate six major bioactive flavonolignans in silymarin, which are based on the use of a liquid chromatographic-tandem mass spectrometry (LC-MS/MS). The standard calibration curves presented a linearity effect with the correlation coefficient ($r^2$) > 0.999. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $0.3{\sim}9.0{\mu}g/L$ and $0.8{\sim}27.3{\mu}g/L$, respectively. The recovery results ranged between 96.2~98.6% at 3 different concentration levels, and its relative standard deviations (RSDs) were less than 5% as noted in this study. The proposed analytical method was characterized with a noted high resolution of the individual silymarin constituents, and the assay was fully validated as well. Our research can provide a significant scientific evidence that can be useful to amend the silymarin test method for the Health Functional Food Code.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.767-774
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• 1998

This study has been carried out to measure the amount of the daily intake by Korean on preservatives (Dehydroacetic acid, Benzoic acid and ρ-Hydroxybenzoic acid asters) in foods. The amounts of preservatives were determined by HPLC in foods such as butter, cheese, margarine, aloe gel, carbonated beverages, mixed beverage, ginseng beverage, red ginseng drink, soy sauce, fruit and vegetable juices (except unheated fruit-vegetable juice), vineger, seasonings, fruit and vegetables only on the peel, fruit wine, rice wine and unrefined rice wine. The recovery ranges were found to be 99.2% for dehydroacetic Acid, 95.8% for benzoic acid and $94.2{\sim}97.2%$ for ${\rho}-hydroxybenzoic$ acid in foods, respectively. The data of average food intake for each food items per capita per day were obtained from the report of national nutrition survey carried by the Ministry of Health and Welfare in 1997. The detected number of samples and average intake range of preservatives have been figured cut to $ND{\sim}290.0{\;}ppm$ for dehydroacetic acid, $ND{\sim}400.0{\;}ppm$ for benzoic acid and $ND{\sim}93.9{\;}ppm$ for ${\rho}-hydroxybenzoic$ acid esters, respectively. Estimated daily intake (EDI) of each additives per capita per day were shown as follows; 1.56 mg for dehydroacetic acid, 2.25 mg for benzoic acid and 0.44 mg for ${\rho}-hydroxybenzoic$ acid esters in total respectively and these values were evaluated to be much lower than that of FAO/WHO's acceptable daily intake (ADI) $0{\sim}5{\;}mg/kg$ b.w./day for benzoic acid and $0{\sim}10{\;}mg/kg$ b.w./day for ${\rho}-hydroxybenzoic$ acid esters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.629-636
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• 1999

Gonadal development, gametogenesis, reproductive cycle, egg-diameter and composition, condition factor, and the first sexual maturity of the clam, Potamocorbula amurensis were investigated by histological observation. Samples were collected monthly from the tidal flat of Moonpo, Puan-gun, Chollabuk-do, west coast of Korea from November 1996 to October 1997. P. amurensis is dioecious and oviparous. The gonads were composed of a number of gametogenic follicles. The oogonia and fully ripe oocytes were $9\~12\mu$m and $50\~60\mu$m in diameter, respectively. Each of the spermatogenic follicle formed stratified layers composed of spermatogonia, spermatocytes spermatids, and spermatozoa in groups on the follicular wall. The reproductive cycle of P. amurensis could be classified into five successive stages: early active, late active, ripe, partially spawned, and recovery. Spawning occurred twice a year from May to July and from September to October, the main spawning seasons also appeared twice a year between May and June, and in October when the water temperatures reached above $18^{\circ}C$. The monthly changes in the condition factor were closely related with the reproductive cycle. Minimum size for the sexual maturation of female and male were 8.1 mm in shell length. There were two patterns for the gametogenesis: 1. After spawning, the undischarged ripe oocytes and spermatozoa in the follicles were degenerated and absorbed, but in part, the existing follicles were not contracted significantly and then they took part in new gametogenesis within one or two months (especially, in summer). 2. After spawning, each follicle was contracted, thereafter gametogenesis again occurred in newly formed follicles.

• Resources Recycling
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• v.17 no.1
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• pp.80-87
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• 2008

Cementation and solvent extraction processes were studied to separate nickel and iron ions from the $H_2SO_4$ leaching solution with 47 g/L $Fe(Fe^{2+}/Fe^{3+}=1.03),$, 23.5 g/L Ni and 0.90M $H_2SO_4$ which leached from Fe-Ni alloy. Iron powder was used as a reducing agent for the cementation of Ni ion from the leaching solution. The reduction percentage of Ni ion was $17{\sim}20%$ by adding 4 times stoichiometric amount of iron powder at $60{\sim}80$. This may result from the fact that the cementation of Ni ion occurred after the reduction of $Fe^{3+}$ to $Fe^{2+}$ and the neutralization of $H_2SO_4$ with iron powder. The cementation process was proved to be unfeasible for the separation/recovery of Ni ion from the leaching solution including $Fe^{3+}$ as a major component. $Fe^{2+}$ present in the leaching solution was converted to $Fe^{3+}$ for solvent extraction of Fe ion using D2EHPA in kerosene as a extractant. The oxidation of $Fe^{2+}$ to $Fe^{3+}$ was completed by the addition of 1.2 times stoichiometric amount of 35% $H_2SO_4$. 99.6% $Fe^{3+}$ was extracted from the leaching solution (23.5 g/L $Fe^{3+}$) by 4 stages cross-current extraction using 20 vol.% D2EHPA in kerosene. $NiSO_4$ solution with 98.5% purity was recovered from the $H_2SO_4$ leaching solution of scrapped Fe-Ni alloy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.85-88
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• 2015

This study attempted to establish an HPLC analysis method for determination of marker compounds as a part of material standardization for the development of health functional food materials from Perilla frutescens Britton var. acuta Kudo. The quantitative determination method of rosmarinic acid as a marker compound of P. frutescens Britton var. acuta Kudo extract (PFE) was optimized by HPLC analysis using a C18 column ($4.6{\times}150mm$, $5{\mu}m$) with 0.1% acetic acid as the elution gradient and methanol as the mobile phase at a flow rate of 1 mL/min and detection wavelength of 280 nm. The HPLC/UV method was applied successfully to quantification of the marker compound in PFE after validation of the method with linearity, accuracy, and precision. The method showed high linearity in the calibration curve at a coefficient of correlation ($R^2$) of 0.9995, and the limit of detection and limit of quantitation were $0.36{\mu}g/mL$ and $1.2{\mu}g/mL$, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 3.21% and 1.43%, respectively. Recovery rate test at rosmarinic acid concentrations of 12.5, 25 and $50{\mu}g/mL$ scored between 97.04~98.98% with RSD values from 0.25~1.97%. These results indicate that the established HPLC method is very useful for the determination of marker compound in PFE to develop a health functional material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1127-1132
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• 2006

In our previous study, a novel herb mixture (HIM-I) of Angelica gigas radix, Cnidium officinale rhizoma, and Paeonia japonica radix was developed to protect the intestinal and immune systems and promote its recovery against radiation damage. A new herbal composition (HemoHIM) with the high immune modulating activity was developed from HIM-I. HIM-I was fractionated into ethanol fraction (HIM-I-E) and polysaccharide fraction (HIM-I-P). And HemoHIM was prepared by adding HIM-I-P to HIM-I. HemoHIM showed more effective than HIM-I in immune modulation as well as radioprotection. The present study is designed to investigate the protective effects of HIM-I, HIM-I-P, and HemoHIM on hydrogen peroxide $(H_2O_2)$ induced apoptosis of human promyelocytic leukemia (HL-60) cells. It was shown that $H_2O_2$ treatment reduced the viability of cells, and increased appearance of DNA ladders, hypodiploid (subG1) cells, and phosphatidylserine translocation level. Pretreatment of HemoHIM significantly reduced the cytotoxic effect induced by $H_2O_2$, associated with reducing the translocation of phosphatidylserine, hypodiploid cells and DNA ladders. HemoHIM appeared to be more protective than HIM-I against $H_2O_2$ induced apoptosis whereas, it exhibited similar activity to HIM-I-P. These results indicated that HemoHIM might be an useful agent for protection against oxidative stress $(H_2O_2)-induced$ apoptosis as well as immune modulation, especially since it is a relatively nontoxic natural product.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.69-83
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• 2011

The aim of the research was to provide basic information for a suitable management and utilization of protected trees by law. To achieve this aim, this study investigated the current state, management status and utilization of protected trees by law in Gyeongsan city. The result of the current state of protected trees indicated that there were 55 protected trees designated since 1982. These trees consisted of 8 species which were located at 41 places. Major species was Sophora japonica (30.9%), followed by Zelkova serrata (23.6%). The protected trees have been used as sacred trees (45.5%) in the villages, followed by scenic trees (36.7%). 38.2% of the protected trees were 200 to 300 years old and 54.6% of the trees were 15 to 30 m in height. 34% of the protected trees were located in the villages, followed by beside road (19.5%). Single trees (78%) were mostly planted. The result of the management status indicated that 58.5% of the root area in protected trees were covered with bare ground, followed by gravel mulch (19.5%). The average of soil hardness was 9.64 mm. The safety fence of tree was installed at 9 places (22%) and a stone wall was built at 22 places (53.7%). 70.9% of the protected trees had a surgical operation to prevent cavities and to cure decay. Granite stone signs were installed at 33 places. The result of the utilization of protected trees indicated that 13 places were used as a rest area in the villages. It consisted of shelters, benches, athletic facilities and outdoor tables. The research suggested potential places for a mini park(pocket park) to recover a local community by using surrounding available land and improving current rest areas of protected trees. The research presented here is a first step towards a more comprehensive analysis of protected trees in Gyeongsan and further research is needed.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.547-551
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• 2009

A new commercial rice variety "Chilbo" is a japonica rice (Oryza sativa L.) with resistance to rice stripe virus and high grain quality. It was developed by the rice breeding team of Yeongdeog Substation, NICS, RDA in 2007. This variety was derived from a cross between "Yeongdeog 26" with wind tolerance and lodging resistance and "Koshihikari" with good grain quality. A promising line, YR21324-119-3-2 was selected by a pedigree breeding method and designated as "Yeongdeog 44" in 2004. Regional adaptation yield trials were carried out at eleven locations from 2005 to 2007. As a result, "Yeongdeog 44" was released as a high yielding rice variety with high grain qualilty and virus resistance with the name of "Chilbo". It is short 76cm in culm length and has medium-late growth duration. This variety is resistant to stripe virus and middle resistant to leaf blast disease. It is also tolerant to cold, dried wind. Milled rice kernel of "Chilbo" is translucent, clear in chalkiness. Panel test proved that and it has good eating quality. Head rice ratio of Chilbo is high compared to the check variety, Hwaseongbyeo. Yield potential of "Chilbo" in milled rice is about 5.57MT/ha at ordinary fertilizer level of local adaptability test. This variety would be adaptable to Yeongnam plain, south & east-south coastal, south mid-mountainous, middle plain area of Korean peninsula.