• Pediatric Infection and Vaccine
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• v.25 no.3
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• pp.156-164
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• 2018

Purpose: We aimed to identify the epidemiology and the clinical characteristics of human parainfluenza virus type 4 (HPIV-4) infection compared to HPIVs 1-3 infections in Korean children. Methods: We reviewed medical records of children with HPIV infection who visited Seoul National University Children's Hospital from 2015 to 2017. Detection of respiratory viruses was performed using real time-polymerase chain reaction (rt-PCR), which could differentiate HPIVs 1-4. Diagnosis was classified as a febrile illness, upper respiratory tract infection (URI), croup, bronchiolitis, or pneumonia. The epidemiology, demographic features, and clinical characteristics among HPIV types were compared. The clinical data were analyzed only for the previously healthy children. Results: Of the 472 children diagnosed with HPIV infection, 108 (22.9%) were previously healthy: 24 (22.2%), 19 (17.6%), 39 (36.1%), and 26 (24.1%) in HPIV types 1, 2, 3, and 4, respectively. The median age of children with HPIV-4 infection was 11 (0-195) months: the proportion of children aged < 2 years and 2 to < 5 years were 65.4% and 19.2%, respectively. Clinical diagnoses of HPIV-4 infection were bronchiolitis (38.5%), pneumonia (30.8%), and URI (30.8%). Croup was the most prevalent in HPIV-2 (21.1%) and none in HPIV-4 infection (P=0.026). Hospital admission rates among HPIV types were not significantly different (P>0.05). Conclusions: We observed seasonal peak of HPIV-4 infection in 2015 and 2017. HPIV-4 was a common respiratory pathogen causing lower respiratory tract infection in hospitalized children.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.316-323
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• 2019

It is difficult to analyze pymetrozine in citrus fruits using the hydromatrix method because of its low efficiency of purification and overlap of matrix and pymetrozine peaks. Liquid-liquid extraction can analyze pymetrozine in citrus fruits using dichloromethane. Since low pH interferes with the extraction of pymetrozine, the extracts of citrus fruits were maintained over pH 7.0 by adding borax buffer and 1 N NaOH in the improved method. According to the improved method, citrus fruits (such as lemon, lime, orange, tangerine, and grapefruit) were extracted and purified for HPLC-photo diode array analysis. The results of validation were as follows: $4.360{\mu}g/kg$ of limit of detection, $14.533{\mu}g/kg$ of limit of quantitation, and 0.007 mg/kg of method quantitative limit. Citrus fruits spiked with pymetrozine showed a recovery range from 71.8 to 83.7% and a coefficient of variation below 6%. Thus, the improved method can efficiently analyze pymetrozine in citrus fruits.

• Analytical Science and Technology
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• v.20 no.4
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• pp.308-314
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• 2007

The analytical method of HPLC with the radial-flow electrochemical cell (RFEC) has been developed to determine doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin simultaneously by employing a reversed-phase chromatography. Anthracyclines were detected at -0.74 V vs. a Ag/AgCl (0.01 M NaCl) reference electrode, a potential of diffusion current plateau in the mobile phase. At a $V_f$ of 1.0 mL/min doxorubicin, epirubicin, daunorubicin and idarubicin appeared at a retention time ($t_r$) of 6.4 min, 7.4 min, 12.7 min and 18.4 min, respectively, while at a $V_f$ of 0.6 mL/min, doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin appeared at a $t_r$ of 9.9 min, 11.5 min, 13.5 min, 19.6 min and 28.7 min, respectively. The linearity between each anthracycline injected ($2.40{\times}10^{-7}M{\sim}1.42{\times}10^{-5}M$) and peak area (charge) was excellent with the square of the correlation coefficient ($R^2$) higher than 0.999. The detection limits were $1.0{\times}10^{-8}M{\sim}1.5{\times}10^{-7}M$ for the five anthracyclines. Within-day precision for the five anthracyclines were in reasonable relative standard deviations less than 3 % ($1.00{\times}10^{-6}M{\sim}1.42{\times}10^{-5}M$) except the lower concentrations less than $0.7{\mu}M$. Solid phase extractions of $1.00{\times}10^{-5}M$ epirubicin, $0.48{\times}10^{-5}M$ nogalamycin and $1.52{\times}10^{-5}M$ daunorubicin from human serum with a $C_{18}$ cartridge resulted in 97 %, 100 % and 90 % of recoveries, respectively.