• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.152-159
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• 2008

The purpose of this study was to determine the accurate quantification of vitamin A in infant formula by comparing two different standard stock solutions as well as various sample weights using high performance liquid chromatography. The sources of uncertainty in measurement, such as sample weight, final smaple vloume, and the instrumental results, were identified and used as parameters to determine the combined standard uncertainty based on GUM(guide to the expression of uncertainty in measurement) and the Draft EURACHEM/CITAC Guide. The uncertainty components in measuring were identified as standard weight, purity, molecular weight, dilution of the standard solution, calibration curve, recovery, reproducibility, sample weight, and final sample volume. Each uncertainty component was evaluated for type A and type B and included to calculate the combined uncertainty. The analytical results and combined standard uncertainties of vitamin A according to the two different methods of stock solution preparation were 627 ${\pm}$ 33 ${\mu}$g R.E./100 g for 1,000 mg/L of stock solution, and 627 ${\pm}$ 49 ${\mu}$g R.E./100 g for 100 mg/L of stock solution. The analytical results and combined standard uncertainties of vitamin A according to the various sample weighs were 622 ${\pm}$ 48 ${\mu}$g R.E./100 g, 627 ${\pm}$ 33 ${\mu}$g R.E./100 g, and 491 ${\pm}$ 23 ${\mu}$g R.E./100 g for 1 g, 2 g, and 5 g of sampling, respectively. These data indicate that the preparation method of standard stock solution and the smaple amount were main sources of uncertainty in the analysis results for vitamin A. Preparing 1,000 mg/L of stock solution for standard material sampling rather than 100 mg, and sampling not more than 2 g of infant formula, would be effective for reducing differences in the results as well as uncertainty.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.221-227
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• 2002

Column experiments were performed to evaluate the removal efficiency of soil vapor extraction (SVE) iota TCE (trichloroethylene) and toluene in soil. Homogeneous Ottawa sands and real soils collected from contaminated area were used to investigate the effect of soil properties and SVE operation conditions on the removal efficiency. In column teats with two different sizes of Ottawa sand, the maximum effluent TCE concentration in a coarse sand column was 442 mg/L and 337 mg/L in a fine sand column. However, after 20 liter gas flushing, the effluent concentrations were very similar and more than 90% of initial TCE mass were removed from the column. For two real contaminated soil columns, the maximum effluent concentration decreased 50% compared with that in the homogeneous Ottawa coarse sand column, but 99% of initial TCE mass were extracted from the column within 40 liter air flushing, suggesting that SVE is very available to remove volatile NAPLs in the contaminated soil. To investigate the effect of contaminant existing time on the removal efficiency, an Ottawa sand column was left stable for one week after TCE was injected and the gas extraction was applied into the column. Its effluent concentration trend was very similar to those for other Ottawa sand columns except that the residual TCE after the air flushing showed relatively high. Column tests with different water contents were performed and results showed high removal efficiency even in a high water content sand column. Toluene as one of BTEX compounds was used in an Ottawa sand column and a real soil column. Removal trends were similar to those in TCE contaminated columns and more than 98% of initial toluene mass were removed with SVE in both column.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.69-79
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• 2011

This study was conducted to estimate effects of by-products of medical herbs replacing rice straw on in vitro fermentation characteristics. Each trial was composed of five treatments including medical herbs : rice straw (%) = 20 : 80 (T1), 40 : 60 (T2), 50 : 50 (T3), 100 : 0 (T4) and the control. Each treatment had eight fermentation times (3, 6, 9, 12, 24, 36, 48 and 72 hours) with three replications. The gas production and DM degradation were significantly (P<0.05) increased by supplementation, especially T4, during the whole fermentation periods. Methane production increased along with addition of by-products similar to the gas production and DM degradation. The pH values ranged from 5.39 to 6.80 and were significantly (P<0.05) decreased by supplementation of by-products of medical herbs. Microbial growth rates reached the peak at between 36 and 48h, thereafter tended to decrease. Although there were no significant differences in the enzyme activities, there was a tendency of increase in T4 treatment. From above results, the replacement levels, particularly 100% replacement of rice straw by by-products of medical herbs, resulted in improving the in vitro fermentation characteristics such as increasing gas production, microbial growth and DM degradation. Also it may help digestion by increasing enzyme activities.

• Journal of Korean Classical Literature and Education
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• no.34
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• pp.149-191
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• 2017

This study examines Korean language translations of traditional Chinese hansi in the 1910s and 1920s. In the $20^{th}$ century, many poets translated Chinese and Korean traditional hansi into Korean. In the early $20^{th}$ century, Korean language began to be used as a national public language. At that time, not only hansi but also poetry from several other languages had been translated into Korean. Choi Nam-sun in the 1910s and Kim So-woel, Kim Eok, and Lee Kwang-su in the 1920s translated Chinese traditional hansi, focusing on famous Dang dynasty poetry from Tu Fu and Li Bai, etc. Choi Nam-sun's translation in the 1910s aimed to consider poetry as a written literature. On the contrary, Kim So-woel, Kim Eok, and Lee Kwang-su believed that Korean modern verse literature should be songs as well as poetry, and their translations in the 1920s aimed to create songs as spoken literature by focusing on orality and universality. Though Korean is now the language, the literary history of hansi continues in modern poetry.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.50-50
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• 2019

본 연구는 국내 자생 국화과의 산국속 3종을 대상으로 국립백두대간수목원 시드뱅크 내 장기저장 가능성을 확인하고자 수행되었다. 국화과 3종의 종자는 경북 봉화군 춘양면에서 2017년 11월에 채종한 후 선별하였다. 종자는 저장조건별($-20^{\circ}C$, 40%RH /$5^{\circ}C$, 30%RH /$15^{\circ}C$, 15%RH) 12주간 저장하여 2주단위로 발아실험을 실시하였다. 발아실험은 광12시간으로 25/15(12/12h)$^{\circ}C$ 변온조건으로 진행하였다. 종자는 10립 3반복으로 1% Agar배지에 치상하여 유근이 1mm 이상 출현한 것을 발아립으로 정의하였다. 평균발아율(GP)과 발아속도(MGT)를 조사하였다. 구절초를 조건별 2주 저장 후 평균발아율과 평균발아일수를 조사한 결과 $-20^{\circ}C/5^{\circ}C/15^{\circ}C$에서 각각 100%, $4.0{\pm}0.09$일 / $96.7{\pm}3.33%$, $3.7{\pm}0.08$일 / $93.3{\pm}3.33%$, $3.6{\pm}0.11$일로 조사 되었으며 12주 저장 후 100%, $4.1{\pm}0.27$일 / $96.7{\pm}3.33%$, $4.4{\pm}0.21$일 / $96.7{\pm}3.33%$, $3.7{\pm}0.13$일로 조사되어 저장 후 발아율의 감소를 보이지 않았으며 $5^{\circ}C$ 저장에서 평균발아일수가 길어지는 경향을 보였다. 포천구절초의 경우 $-20^{\circ}C/5^{\circ}C/15^{\circ}C$에서 각각 $96.7{\pm}3.33%$, $4.4{\pm}0.36$일 / 100%, $4.2{\pm}0.09$일 / $93.3{\pm}6.67%$, $4.1{\pm}0.22$일로 조사 되었으며 12주 저장 후 $96.7{\pm}3.33%$, $4.2{\pm}0.30$일 / $96.7{\pm}3.33%$, $4.2{\pm}0.15$일 / 100%, $4.0{\pm}0.09$일로 조사 되어 저장 전 후 차이를 확인 할 수 없었다. 한라구절초의 경우 $-20^{\circ}C/5^{\circ}C/15^{\circ}C$에서 각각 $93.3{\pm}3.33%$, $3.4{\pm}0.10$일 / $93.3{\pm}3.33%$, $3.7{\pm}0.08$일 / $93.3{\pm}6.67%$, $3.8{\pm}0.02$일로 조사 되었으며 12주 저장 후 $96.7{\pm}3.33%$, $4.0{\pm}0.21$일 / $96.7{\pm}3.33%$, $4.2{\pm}0.03$일 / $96.7{\pm}3.33%$, $3.8{\pm}0.09$일로 조사되어 발아율이 소폭 상승하는 경향을 보였다. 산국속 3종의 종자는 12주 저장 후 기간 및 저장조건에 따른 평균발아율과 발아속도에서 유의적인 차이를 나타내지 않았다. 이상의 결과로 산국속 3종 구절초, 포천구절초, 한라구절초의 종자는 저장기간 및 조건에 대해 민감한 반응을 보이지 않아 장기저장이 가능한 진정종자(Orthodox seed)로 판단된다.

• 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.

• Research in Plant Disease
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• v.26 no.4
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• pp.272-278
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• 2020

The severe lettuce damage caused by Paratylenchus projectus was first reported in 2019 in Korea. To find high-value rotation crops for the control of P. projectus, nine vegetables, Brassica juncea (leaf mustard), B. rapa subsp. nipposinica (kyona), B. oleracea var. italica (broccoli), B. rapa subsp. chinensis (bok choy), B. oleracea var. viridis (kale), B. oleracea var. gongylodes (kohlrabi), Cichorium endivia (endive), C. intybus (chicory), Ipomoea aquatica (morning glory) were planted in d-10-cm clay pots in greenhouse. The growth of vegetables was compared between inoculated with 3,000 P. projectus per 100 ㎤ of soil and non-inoculated. Treatments were replicated 10 times. After 100 days, the reduction of fresh top weight was 30.4% in C. intybus, 35.1% in I. aquatica, 36.9% in B. oleracea var. acephala, 40.5% in C. endivia, 42.1% in B. rapa, 47.5% in B. rapa subsp. nipposinica, 50.4% in B. oleracea var. gonglodes, 56.3% in B. oleracea var. italica, and 66.0% in B. juncea. Nematode multiplication rates (Pf/Pi) were lower in I. aquatica (0.64) and C. endivia (1.1), but higher in B. oleracea var. gongylodes (2.54). Considering these results, I. aquatica is suitable for the rotation crop with lettuce until better rotation crops developed.

• Journal of fish pathology
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• v.34 no.1
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• pp.71-80
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• 2021

Cephalexin, a semi-synthetic cephalosporin antibiotic, has long been used in fish aquaculture in various countries under legal authorization. The drug is thus widely available for use in other aquatic species except fishes like the crustacean whiteleg shrimp. This study aims to develop a sensitive method for laboratory residue studies to adopt in withdrawal period determinations. Through repeated trials from the existing methods developed for other food animal tissues, it was possible to achieve a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The results showed that at a concentration of 0.1 mg/kg, the recovery rate was 81.79%, and C.V. value was 8.2%, which meet the recovery rate and C.V. recommended by Codex guideline. After satisfactory validation of analytical procedures, applicability to the shrimp tissue was confirmed in experimentally cephalexin-treated whiteleg shrimp. As a result, most muscle samples were detected below the limit of quantification (0.05 mg/kg) after day 3, and most hepatopancreas samples were detected below the limit of quantification after day 14. In particular, the limit of quantification 0.05 ppm with the presently developed method suggests sufficient sensitive over the current legal maximum residue limit of 0.2 mg/kg set for fishes.

• Journal of Food Hygiene and Safety
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• v.36 no.3
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• pp.220-227
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• 2021

Fluoroimide is a fungicide and is also used as a pesticide for persimmons and potatoes. The established fluoroimide pesticide analysis method takes a long time to perform and uses benzene, a carcinogen. In addition, a lower limit of quantification is required due to enforcement of the Positive List System. Therefore, this study aimed to improve the analysis method for residual fluoroimide to resolve the problems associated with the current method. The analytical method was improved with reference to the increased stability of fluoroimide under acidic conditions. Fluoroimide was extracted under acidic conditions by hydrogen chloride (4 N) and acetic acid. MgSO₄ and NaCl were used with acetonitrile. C₁₈ (octadecylsilane) 500 mg and graphitized carbon black 40 mg were used in the purification process. The experiment was conducted with agricultural products (hulled rice, potato, soybean, mandarin, green pepper), and liquid chromatograph-tandem mass spectrometry was used for the instrumental analysis. Recovery of fluoroimide was 85.7-106.9% with relative standard deviations (RSDs) of less than 15.6%. This study reports an improved method for the analysis of fluoroimide that might contribute to safety by substituting the use of benzene, a harmful solvent. Furthermore, the use of QuEChERS increased the efficiency of the improved method. Finally, this research confirmed the precise limit of quantification and these results could be used to improve the analysis of other residual pesticides in agricultural products.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.25-33
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• 2021

Purpose : The purpose of this study is to evaluate the accuracy and usefulness of the Trigger mode for the Respiratory Gated Radiation Therapy (RGRT) Materials and methods : A QUASAR respiratory phantom that inserted a 3 mm fiducial marker (a gold marker) was used to estimate the accuracy of the Trigger mode. And the 20 bpm was used as reference respiration rate in this study. The marker that placed at the center of the phantom was contoured, and the lower threshold of a gating window was fixed at 2.0 mm using an OBI with Truebeam STx^TM. The upper threshold was measured every 0.5 mm from 1.0 mm to 3.0 mm. The respiration rates were changed every 10 bpm from 10 bpm to 60 bpm. We repeatedly measured five times to check the error rate of the trigger mode in the same condition. Result : The differences of a distance from a peak phase to upper threshold, 1.0 to 3.0 mm at a 20 bpm as a reference for 3 days in a row were 0.68±0.05 mm, 0.91±0.03 mm, 1.23±0.03 mm, 1.42±0.04 mm, and 1.66±0.06 mm, respectively. Measurement result of changes in respiratory rate compared to baseline respiratory rate in maximum absolute difference. The coefficient of determination (R2) to estimate the correlation between the respiration velocity and variation of absolute difference was on average 0.838, 0.887, 0.770, 0.850, and 0.906. The p-values of all the variables were below 0.05. Conclusion : Using Trigger mode during respiratory gated radiation therapy (RGRT), accuracy and usefulness of trigger mode at reference breathing rate were confirmed. However, inaccuracies depending on the rate of breathing it could be uncertain in case of respiration rate is faster than 20 bpm as a standard respiration rate compared to slower than 20 bpm. Consequently, when conducting a RGRT using the trigger mode, real time monitoring is required with well educated respiration.