• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.30-39
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• 2019

An analytical method was developed for the determination of sedaxane in agricultural products using liquid chromatograph-tandem mass spectrometry (LC-MS/MS). The samples were extracted with acetonitrile and partitioned with dichloromethane to remove the interference, and then purified by using silica SPE cartridges to clean up. The analytes were quantified and confirmed by using LC-MS/MS in positive ion mode using multiple reaction monitoring (MRM). The matrix-matched calibration curves were linear over the calibration ranges ($0.001-0.25{\mu}g/mL$) into a blank extract with $r^2$>0.99. For validation, recovery tests were carried out at three different concentration levels (LOQ, 10LOQ, and 50LOQ, n=5) with five replicates performed at each level. The recoveries were ranged between 74.5 to 100.8% with relative standard deviations (RSDs) of less than 12.1% for all analytes. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL 40, 2003) and Food Safety Evaluation Department guidelines (2016). The proposed analytical method was accurate, effective and sensitive for sedaxane determination in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.13-21
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• 2019

A method was developed for the simultaneous detection of an antibiotic fungicide, streptomycin, and its metabolite (dihydrostreptomycin) in agricultural products using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using methanol adjusted to pH 3 using formic acid, and purified with a HLB (Hydrophilic lipophilic balance) cartridge. The matrix-matched calibration curves were constructed using seven concentration levels, from 0.001 to 0.1 mg/kg, and linearity of five agricultural products (hulled rice, potato, soybean, mandarin, green pepper), with coefficients of determination $(R^2){\geq}0.9906$, for streptomycin and dihydrostreptomycin. The mean recoveries at three fortification levels (LOQ, $LOQ{\times}10$, $LOQ{\times}50$, n = 5) were from 72.0~116.5% and from 72.1~116.0%, and relative standard deviations were less than 12.3% and 12.5%, respectively. The limits of quantification (LOQ) were 0.01 mg/kg, which are satisfactory for quantification levels corresponding with the Positive List System. All optimized results satisfied the criteria ranges requested in the Codex guidelines and the Food Safety Evaluation Department guidelines. The present study could serve as a reference for the establishment of maximum residue limits and be used as basic data for detection of streptomycin and dihydrostreptomycin in food.

• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.112-129
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• 2011

This paper was written to understand, through the types and production techniques, how cooking vessels of Baekje Hanseong period had evolved, - the cooking vessels that were excavated from the historic sites of Baekje Hanseong Period such as Mongchontoseong and Pungnaptoseong of Seoul, the ancient tomb group of Seokchon-dong, and Misari historic site of Hanam. First, the results produced through the analysis of types of these cooking vessels are as followings: as for deep bowls, the maximum body diameter is found on the top of pottery, while as for an egg-shaped pottery, the maximum body diameter is found on the middle height of pottery. However, as for the rim diameter ratio to the neck diameter ratio of pottery, the said two typed potteries were shown to have smaller ones. In consideration of each historic site, as for deep bowls, the ancient tomb group of Seokchon-dong had potteries that had less volumes, were deeper, and had higher maximum body diameters. When it comes to an egg-shaped pottery, Pungnaptoseong had the potteries that were deeper than those of Misari historic site, and their potteries also had the maximum body diameter found on the middle height of pottery, and larger rim diameter ratio to the neck diameter of the pottery. The results produced though the analysis of the production techniques of these cooking vessels are as followings: in the case of deep bowls, as the width of a volume category gets larger, the pottery stamping with an anvil including patterns was more frequently used for pottery production. In this case, simultaneously braid patterns were frequently found on the outer sides of these potteries. In addition, it was found the basal walls of these potteries were thinnest in all typed potteries. This shows there occurred technique transitions according to the time flow. When it comes to an egg-shaped pottery as well, the pottery produced by using an anvil had the thinnest basal wall and its rim diameter ratio to its neck diameter ratio was smaller. Also around the mouth of this pottery, traces were found on its front, the traces formed by the strong rotating power. It is determined these two typed potteries were all produced by using an anvil to have thinner walls. Then, how these potteries were used? In the case of deep bowls, liquid food was put on a hearth or ground to be cooked whereas in the case of an egg-shaped pottery, the pottery was put on a puttumak(kitchen stove) mainly for boiling water. The deep bowls and egg-shaped potteries excavated from the center areas of Baekje Hanseong Period were not clearly determined about when their pastes or firing times were, but as for their production techniques, it was possible to check how they had developed. Moreover, it was determined that in the changing aspects of their production techniques, temporalite is also reflected.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.413-421
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• 2019

Purpose: Astragalus membranaceus (AM) is an important traditional medicinal herb. Pharmacological research has indicated that AM has various physiological activities such as antioxidant, anti-inflammatory, immunoregulatory, anticancer, hypolipidemic, antihyperglycemic, and hepatoprotective activities. The bioactive substances responsible for the physiological activities in AM, including many antioxidant substances, change during the roasting process. This study investigated and compared the changes in the antioxidant constituents of AM caused by roasting. Methods: DPPH (1,1-diphenyl-2-picryl hydrazyl) and $ABTS^+$ (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activities and their total phenolic content (TPC) were measured. High-performance liquid chromatography (HPLC) analysis was performed to confirm any changes in the isoflavonoids of roasted AM (R-AM),. The cell viability of UVB-induced HDF (Human dermal fibroblast) cells treated with AM and R-AM extracts was investigated. The comet assay was used to examine the inhibitory effects of R-AM extracts on DNA damage caused by oxidative stress. Results: The DPPH and $ABTS^+$ radical scavenging activities were $564.6{\pm}20.9$ and $108.2{\pm}3.1$ ($IC_{50}$ value) respectively, from the 2R-AM. The total phenol content was $47.80{\pm}1.40mg$ GAE/g from the 1R-AM. The values of calycosin and formononetin, which are the known isoflavonoid constituents of AM, were $778.58{\pm}2.72$ and $726.80{\pm}3.45{\mu}g/g$ respectively, from the 2R-AM. Treatment of the HDF cells with R-AM ($50{\sim}200{\mu}g/mL$) did not affect the cell viability. Furthermore, the R-AM extracts effectively protected against UVB-induced DNA damage. Conclusion: The findings of this study indicate that R-AM increases its isoflavonoid constituents and protects against UVB-induced DNA damage in HDF cells.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.235-241
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• 2019

An analytical method was developed for the determination of an antibiotic fungicide, kasugamycin, in agricultural products (hulled rice, potato, soybean, mandarin and green pepper) using liquid chromatographytandem mass spectrometry (LC-MS/MS). Samples were extracted with methanol adjusted to pH 13 using 1 N sodium hydroxide, and purified with a HLB (hydrophilic lipophilic balance) cartridge. Linearity of a matrix-matched calibration curve using seven concentration levels, from 0.001 to 0.1 mg/kg, was excellent with a correlation coefficient ($R^2$) of more than 0.9998. The limits of detection (LOD) and quantification (LOQ) of instrument were 0.0005 and $0.001{\mu}g/mL$, respectively, and the LOQ of analytical method calculated as 0.01 mg/kg. The average recoveries at three spiking levels (LOQ, $LOQ{\times}10$, $LOQ{\times}50$, n=5) were in the range of 71.2~95.4% with relative standard deviation of less than 12.1%. The developed method was simple and all optimized results was satisfied with the criteria ranges requested in the Codex guidelines and Food Safety Evaluation Department guidelines. The present study could be served as a reference for the establishment of maximum residue limits (MRL) of kasugamycin and be used as basic data for safety management relative to kasugamycin residues in imported and domestic agricultural products.

• Journal of Life Science
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• v.29 no.5
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• pp.596-606
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• 2019

The study investigated the physiochemical properties and the antioxidant and anti-inflammatory activities of the sea tangle (Saccharina japonica) in a water extract before (STWE) and after (STFL) fermentation with Lactobacillus brevis. The pH values of STWE and STFL were 6.18 and 4.16, and the sugar contents were $8.50^{\circ}Brix$ and $7.40^{\circ}Brix$, respectively. The main free amino acids of STWE and STFL were glutamic acid, aspartic acid, and alanine, and the ${\gamma}$-amino butyric acid (GABA) content was increased by fermentation. The total polyphenol contents of STWE and STFL were 498.29 and 615.77 mg gallic acid equivalent (GAE)/ml, respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of STWE and STFL were markedly increased in a dose-dependent manner, and revealed about 89.89% and 96.94% activities, respectively, at 10% concentration (p<0.05). The superoxide dismutase (SOD) activities of STWE and STFL were also markedly increased in a dose-dependent manner, and the activity of STFL was significantly increased when compared with STWE (p<0.05). The anti-inflammatory activity was examined in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. STWE and STFL decreased the production of reactive oxygen species (ROS), which had levels of about 189.90% and 174.69% at 1% concentration, respectively (p<0.05). The contents of pro-inflammatory cytokines, such as tumor necrosis factor-alpha ($TNF-{\alpha}$) and interleukin-6 (IL-6), were decreased more by addition of STFL than by addition of STWE. The STWE and STFL showed high antioxidant and anti-inflammatory activity, and these activities were increased by fermentation. Therefore, sea tangle extracts can be used as functional food materials.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.115-123
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• 2019

An analytical method was developed for the determination of fenpropimorph, a morpholine fungicide, in hulled rice, potato, soybean, mandarin and green pepper using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation and LC-MS/MS (liquid chromatography-tandem mass spectrometry). The QuEChERS extraction was performed with acetonitrile followed by addition of anhydrous magnesium sulfate and sodium chloride. After centrifugation, d-SPE (dispersive solid phase extraction) cleanup was conducted using anhydrous magnesium sulfate, primary secondary amine sorbents and graphitized carbon black. The matrix-matched calibration curves were constructed using seven concentration levels, from 0.0025 to 0.25 mg/kg, and their correlation coefficient ($R^2$) of five agricultural products were higher than 0.9899. The limits of detection (LOD) and quantification (LOQ) were 0.001 and 0.0025 mg/kg, respectively, and the limits of quantification for the analytical method were 0.01 mg/kg. Average recoveries spiked at three levels (LOQ, $LOQ{\times}10$, $LOQ{\times}50$, n=5) and were in the range of 90.9~110.5% with associated relative standard deviation values less than 5.7%. As a result of the inter-laboratory validation, the average recoveries between the two laboratories were 88.6~101.4% and the coefficient of variation was also below 15%. All optimized results were satisfied the criteria ranges requested in the Codex guidelines and Food Safety Evaluation Department guidelines. This study could serve as a reference for safety management relative to fenpropimorph residues in imported and domestic agricultural products.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.298-309
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• 2021

In this study we sought to develop a simultaneous analysis method for cis-bixin and cis-norbixin, the main components, to detect annatto pigment in food. To establish the optimal test method, the HPLC analysis methods of the European Food Safety Authority (EFSA), Japan's Ministry of Health, Labor and Welfare (MHLW), and National Institute of Food and Drug Safety Evaluation (NIFDS) were compared and reviewed. In addition, a new pretreatment method applicable to various foods was developed after selecting conditions for simultaneous high-performance liquid chromatography (HPLC) analysis in consideration of linearity, limit of detection (LOD), limit of quantification (LOQ), and analysis time. The HPLC analysis method of NIFDS showed the best linearity (R² ≥ 0.999), exhibiting low detection and quantification limits for cis-norbixin and cis-bixin as 0.03, 0.05 ㎍/mL, and 0.097, 0.16 ㎍/mL, respectively. All previously reported pretreatment methods had limitations in various food applications. However, the new pretreatment method showed a high recovery rate for all three main food groups of fish meat and meat products, processed cheese and beverages. This method showed an excellent simultaneous recovery rate of 98% or more for cis-bixin and cis-norbixin. The HPLC analysis method with a new pretreatment method showed high linearity with a coefficient of determination (R²) of 1 for both substances, and the accuracy (recovery rate) and precision (%RSD) were 98% and between 0.4-7.9, respectively. From this result, the optimized analytical method was considered to be very suitable for the simultaneous analysis of cis-bixin and cis-norbixin, two main components of annatto pigment in food.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.194-215
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• 2021

Termites are important decomposers in the ecosystem. They are also economically significant structural pests. In this study, we reviewed the developments of termite control and recent research on termite management to provide information on the prevention and control of termites. In Korea, most of the damage to wooden historical buildings is caused by subterranean termites. Reticulitermes speratus kyushuensis is the main species, which is widely found throughout the country. In the early 1900s, inorganic insecticides, such as arsenic dust, were used for termite control. After the synthesis of chlorinated hydrocarbon pesticide in the 1940s, it was widely utilized and demonstrated high termite control efficacy. However, chlorinated hydrocarbon insecticides were later banned, disappearing from markets after reports emerged concerning environmental contamination and toxicity to humans. Therefore, the termite control industry sought a new termiticide; hence many pesticides were utilized for termite control. Organophosphate (1960s), carbamate (1970s), pyrethroid, and insect growth inhibitor (1980s) were newly synthesized and adopted. In the 1990s, the first commercial baits using chitin synthesis inhibitors (CSI) were developed, providing a means to eliminate an entire colony of subterranean termites around a structure. Many studies have been carried out on soil termiticides (liquid termiticides) and CSI baits to increase their efficacy, and different baits such as aboveground bait stations, fluid bait, and high-durability bait were also developed in the 2000s. In addition, the paradigm of termite control has shifted from localized treatments using soil termiticides to area-wide pest management using CSI baits to create termite-free zones and protect buildings over time. Termite infestations in wooden historical buildings in Korea have been reported since 1980, and considerable attention was drawn in the 1990s when several UNESCO world heritages such as the Jongmyo Shrine and the Janggyeong Panjeon Depositories of Haeinsa Temple were infested by subterranean termites. Since then, a survey of termite infestation in wooden architectural heritage has been conducted, and the National Research Institute of Cultural Heritage and Heritage Care Program regularly monitors those properties. Finally, we suggest termite management using primarily CSI baits, selective application of various soil treatments applied to the object, foundation soil treatment, research and development of durable termite baits, application of area-wide programs for wooden-building complexes, application of integrated termite management (ITM), and regular education for owners and managers to prevent and reduce termite damage.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.67-75
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• 2020

In this paper, by applying LCP substrate, the capacitor and inductor are implemented with a variety of value that can be used in 35 GHz circuits. Depending on how to apply it to the circuit, it is required high value by designing the basic structures such as electrode capacitor and spiral inductor. However they are not available in high-frequency domain, because their SRF(Self-Resonant Frequency) is lower than the frequency of 35-GHz. By finding the limit, this paper devised classifying passive devices for the DC and the high-frequency domain. The basic structure is suitable for DC and microstrip λ/8 length stub structure can be used for high-frequency. The open and short stub structure operate as a capacitor and inductor respectively in the frequency of 35 GHz. If their impedance is known, it is possible to extract the value through the impedance-related equation. By producing with the permittivity 2.9 LCP substrate, the basic structure which are available in the DC constituted a library of capacitance of 1.12 to 13.9 pF and inductance of 0.96 to 4.69 nH, measured respectively. The stub structure available in the high-frequency domain were built libraries of capacitance of 0.07 to 2.88 pF and inductance of 0.34 to 1.27 nH, calculated respectively. The measurements have proven how to diversify value, so libraries can be built more variously. It is possible to integrate with the operation circuit of TRM(Transmit-Receive Module) for the frequency 35-GHz, it will be an alternative to the passive devices that can be properly utilized in the circuit.