• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.203-213
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• 2005

Oxytetracycline, tetracycline, chlortetracycline and doxycycline in honey were separated by solid phase extraction (SPE) and determined with high performance liquid chromatography (HPLC) with UV/Visible detector. Analysis was carried out using following conditions: XTerra $C_8$ column $(3.9\times150mm\;i.d. 5{\mu}m)$, mobile phase composed of 0.01M oxalic acid : methanol : acetonitrile (820 : 80 : 100, v/v/v), isocratic pump at a flow rate of 0.9 ml/min. and $50{\mu}l$ of injection volume, UV/Visible detector with wavelength of 360nm. The calibration curves of four tetracyclines showed linearity $(\gamma^2>0.999)$ at concentration range of $100\~1,000 ng/ml$. The recoveries in fortified honey represented more than $70\%$ with low coefficient of variation $(<10\%)$ for concentration range of four tetracyclines. The detection limits for oxytetracycline, tetracycline, chlortetracycline and doxycycline were 13.8, 14.6, 26.2 and 24.9ng/g in acacia honey. respectively. We also monitored tetracyclines residue in domestic honey [n : 38, acacia (20), wild flower (18) ] and foreign honey [n=22, legally distributed (13), illegally distributed (9)] using modified Charm II screening and HPLC confirmation methods. Seven of the 60 samples $(11.7\%)$ were suspect positive using modified Charm II screening test. Chlortetracycline residue was found in one foreign honey (illegally distributed) tested at concentrations of 0.22 ppm. Conclusively, for more effective control of tetracyclines used in beekeeping should be further survey for residues in honey and also national guidelines (maximum residue limit : MRL) and methods should be obligatory.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.460-466
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• 2012

Perchlorate is used in a number of applications as an oxidizer in solid propellants, munitions and fireworks and is one of the endocrine disrupting chemicals, which interferes with iodide uptake into the thyroid gland. The purpose of this study was to investigate perchlorate occurrence and distribution with a results of analysis of 94 samples collected from military facilities in Korea from October 11 to October 23, 2011. Overall, among all of the 94 samples analyzed, perchlorate was detected in 6.4% of the total number of samples above $4{\mu}g/L$ (minimum reported limit) and the average concentration was $26.1{\mu}g/L$ and the maximum concentration was $107.7{\mu}g/L$ which was observed in surface water near manufacturing site of ammunition. By site classification, perchlorate was detected at one site in 4 manufacturing sites of ammunition and the maximum concentration was $107.7{\mu}g/L$ which was six times higher than that in guideline for perchlorate in Nakdong River and resulted from point source discharge. Perchlorate was detected at 3 sites in 78 measurements for shooting area and the maximum concentration was $12.4{\mu}g/L$ which was collected in dringking water and perchlorate in another sample was detected above MRL in shooting area was collected right away after shooting. These results showed that long term monitoring was needed considering weather conditions and shooting schedules.

• Mycobiology
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• v.34 no.2
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• pp.67-72
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• 2006

Efficacy of resistance induction by the bacterial isolates Pseudomonas putida (TRL2-3), Micrococcus luteus (TRK2-2) and Flexibacteraceae bacterium (MRL412), which were isolated from the rhizosphere of plants growing in Jeju Mountain, were tested in a greenhouse. The disease severity caused by Phytophthora infestans was effectively reduced in the potato plants pre-inoculated with bacterial isolates compared with those of the untreated control plants growing in a greenhouse. In order to estimate the level of protection by the bacterial isolates, Mancozeb WP (Diesen $M^{(R)}$, Kyong nong) and DL-3-amino butyric acid (BABA) were pre-treated, whereas Dimethomorph WP ($Forum^{(R)}$, Kyong nong) and phosphonic acid ($H_{3}PO_{3}$) were post-treated the challenge inoculation with the pathogen. Disease severities of chemical pre-treated as well as post-treated plants were reduced compare to those of the untreated. The disease reduction in the plants pre-treated with Mancozeb WP was the highest, whereas that of post-treated with Dimethomorph WP was the lowest. The yields of plants pre-inoculated with three bacterial isolates were greatly increased than those of control plants. These results suggest that biological control by bacterial isolates might be an alternative strategy against late blight disease in potato plants growing in greenhouse.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.337-342
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• 2007

To obtain the data on the risk assessment of residue levels of organophosphorus and organochlorine pesticides in fresh ginseng and red ginseng extract, the residual pesticides in samples are surveyed with GC-NPD and GC-ECD for quantitative analysis and GC-MSD for qualitative analysis. The residual organophosphorus pesticides, such as diazinon, pyrimethanil, tolclofos-methyl, metalaxyl, diethofencarb, parathion, cyprodinil, tolylfluanid and kresoxim-methyl, are not detected in fresh ginseng from Punggi. The residual organophosphorus pesticides except tolclofos-methyl are not detected in fresh ginseng from Sangju. Average amount of tolclofos-methyl in fresh ginseng from Sangju are $0.054{\pm}0.008\;mg/kg$, representing $18{\pm}2%$ of MRL of 0.03 mg/kg on fresh ginseng in Korea. The residual organochlorine pesticides, such as BHC isomer, DDT isomer, aldrin, azoxystrobin, captan, cypermethrin, deltamethrin, dieldrin, difenoconazole, endosulfan-sulfate, endrin, fenhexamid, quintozene, ${\alpha}$-endosulfan and ${\beta}$-endosulfan, are not detected in fresh ginseng from Punggi and Sangju. The residual organophosphorus and organochlorine pesticides in red ginseng extract from Punggi and Sangju are not detected.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.274-280
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• 2005

A chitinase was purified from the culture supernatant of Paenibacillus illinoisensis KJA-424 by protein precipitation, DEAE-Sephadex anion-exchange chromatography, and Sephadex G-150 gel filtration. The molecular weight of the purified chitinase was 54 kDa on SDS-PAGE and activity staining. Optimal pH and temperature were pH 5.0 and 60$^{circ}$C, the presence of 10 ruM Ag$^{+}$ and Hg$^{2+}$ inhibited the activity by $92.1/%$ and $97.7/%$, and the K$_{m}$ and V$_{max}$ values were 1.12 mg chitin mrl and 1.48$\mu$mol GlcNAc min$^{-1}$, respectively. The enzyme hydrolyzed tetramer to dimer, pentamer to dimer and trimer, and hexamer to dimer, trimer and tetramer, indicating an endo-splitting mechanism. The chitinase had no hydrolytic activity toward dimer and trimer. The chitinase inhibited the mycelial growth of Rhizoctonia solani, suggesting an antifungal property.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.122-129
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• 2020

BACKGROUND: Dissipation patterns of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry grown in plastic-covered greenhouse were evaluated at 7 intervals including the preharvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods. METHODS AND RESULTS: Acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C₁₈ column. The limit of quantitation (LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence. CONCLUSION: The residue levels of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry at 0-day after application were below the specified values by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important to set the pre-harvest residue limit for human health and consumer protection in Korea.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.142-169
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• 2020

BACKGROUND: A new analytical method has been developed to determine 261 pesticide residues in herbal medicines. METHODS AND RESULTS: The extraction of pesticides was carried out by modified method of the Korea Food Standards Codex sample extraction and determination was performed using GC-MS/MS and LC-MS/MS. During the pre-treatment process of the test method, Solid-liquid separation was changed to centrifugation. The method was validated by the precision and accuracy results. 261 pesticides spiked at three level 20, 50, 100 ug/kg in herbal medicines. The limit of quantification of method were 4-40 ug/kg for GC-MS/MS and 2-45 ug/kg for LC-MS/MS, respectively. Among the pesticides analysed by GC-MS/MS and LC-MS/MS, 244 pesticides (94% of total number) in chinese matrimony vine and 224 pesticides (86% of total number) in korean angelica root and 231 pesticides (89% of total number) in jujube and 214 (82% of total number) in cnidium showed recoveries in the range of 70-120% with RSD⪯20%. CONCLUSION: These results indicated that GC-MS/MS and LC-MS/MS analysis with the sample extraction in this study can be applied to multi-residue analysis of pesticides in herbal medicines.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.150.1-150
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• 2003

열무의 안전한 생산을 위한 생산단계에서의 각 농약 잔류량 변화 추이와 최종 소비단계에서의 농산물 안전성 평가자료로 활용하기 위하여 실제 시험포장에 열무를 파종한 후 수확 10일 전에 4 종(diazinon, endosulfan, cypermethrin, cyhalothrin)의 살충제를 각 성분별로 안전사용 기준에 따라 기준량 및 배량의 처리구에 직접 살포하여 열무의 포장상태에서의 잔류량 감소(생물학적 반감기) 변화를 조사하였다. 각 농약별로 2 수준 농도의 표준물질을 첨가하여 실험한 결과 평균회수율은 diazinon 98.7∼99.9%, endosulfan 97.6∼98.5%, cypermethrin 98.3∼99.6%, cyhalothrin 98.4∼99.1%이였고, 검출한계는 diazinon 및 cypermethrin은 0.04 mg/kg, endosulfan은 0.012 mg/kg, cyhalothrin은 0.01 mg/kg 이었다. 약제 살포 후 분해속도가 빠른 성분은 diazinon ＞ endosulfan ＞ cypermethrin ＞cyhalothrin 순이었다. 작물체(열무)내에서 시간의 경과에 따른 잔류량의 변화를 1차 반응으로 표현하여 농약 4종의 살포농도별 생물학적 반감기를 산출한 결과, 기준량 살포의 경우 diazinon 0.9일, endosulfan 2.0일, cypermethrin 2.2일, cyhalothrin 2.5일 그리고 배량 살포의 경우에는 diazinon 1.1일, endosulfan 2.0일, cypermethrin 2.1일, cyhalothrin 2.2일로 나타났다. 안전한 농산물 생산을 위한 열무 중 약제 살포 후 수확일은 잔류허용기준(MRL)을 적용시킬 경우 기준량으로 볼 때 diazinon은 6일 후, endosulfan은 10일 후에 수확하는 것이 바람직한 것으로 나타났으며 합성 피레스로이드계인 cypermethrin과 cyhalothrin은 농약살포 후 2 시간 후에 농약 잔류량이 잔류허용기준 미만으로 나타났다.

• Journal of Korean Foot and Ankle Society
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• v.6 no.2
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• pp.195-200
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• 2002

Purpose: To investigate the MRI and arthroscopic findings of osteochondral lesion of the talus which looked normal on plane radiography. Materials and methods: We investigated the MRI and arthroscopic findings of seven osteochondral lesions in which there were no abnormal finding on plane radiography and no cystic changes on MRI. Average age was 31 years(range, 19-43 years). Arthroscopic findings were classified according to the Ferkel's criteria. Results: History of injury was reported in all cases and the average duration from injury to presentation was 4 years and 4 months. Low signal change in T1WI was found in 6 of 7 lesions, no signal change in 1 case. Low signal change in T2WI was found in 4, no signal change in 3. 6 STIR images were obtained. High signal change was found in 3, no signal change in 2 and intermediate signal change was in 1. Arthroscopic grading was A in 1, C in 1, D in 2 , E in 1 and F in 2. We could not find any correlation between the findings on MRI and arthroscopic examination. Conclusion: We suggest arthroscopic examination is needed for accurate diagnosis of the osteochondral lesions of the talus which looked normal on plane radiography, because they have various MRl findings and high likelihood of existence of unstable cartilage lesions.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.266-271
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• 2006

This study was monitored for 14 pesticide residues in agricultural products for the army, such as fruit vegetables(pepper, cucumber, pumpkin, melon and water melon), leafy vegetables(Korean cabbage, spinach, lettuce, crown daisy, cabbage, green onion), mushrooms(agaric, p'yogo), and bean sprouts produced in Kyunggi-do and Inchon-City. From January to December 2005, ten carbamate pesticides in 356 samples were analyzed by HPLC. One kind of pesticide was detected in 8 samples of detection rate (2.53%), and two pesticides were in one sample of detection rate(0.27%). Aldicarb, bendiocarb, fenobucarb, methiocarb, isoprocarb, and propoxur were not found in all samples. Detection rates of pesticides were 0.84% for methomyl, 0.56% for carbofuran, 0.56% for ethiofencarb, and 0.28% for carbayl. Dectection ranges of pesticides were from 0.01 to 2.9 mg/kg for ethiofencarb, from 0.1 to 0.23 mg/kg for methomyl, from 0.20 to 0.24 mg/kg for carbofuran, and 0.01 mg/kg for carbaryl, respectively. Consequently, detection levels of all pesticides in samples were less than the maximum residue limits(MRLs) in Korea representing that all agricultural products for the army were safe.