• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.247-256
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• 2010

A high-performance liquid chromatographic (HPLC) method was developed to determine buprofezin residues in hulled rice and fruits. The buprofezin residue was extracted with acetone and the extract was stepwise purified by liquid-liquid partition and Florisil column chromatography. For rice samples, acetonitrile/n-hexane partition was additionally employed to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate buprofezin from sample co-extractives, as detected by ultraviolet absorption at 250 nm. Recovery experiment at the limit of quantitation validated that the proposed method could evidently determine the buprofezin residue at the level of 0.02 mg/kg. Mean recoveries from hulled rice, apple, pear, and persimmon samples fortified at three tenfold levels were in the range of 80.8~85.2%, 89.1~98.4%, 88.8~95.7% and 90.8~96.2%, respectively. Relative standard deviations of the analytical method were all less than 5%, irrespective of sample types. A selected-ion monitoring LC/mass spectrometry with positive electrospray ionization was also provided to sensitively confirm the suspected residue.

• Annals of Clinical Neurophysiology
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• v.19 no.1
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• pp.40-45
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• 2017

Background: Telbivudine is a nucleoside analogue used for the treatment of chronic hepatitis B, but it often develops mitochondrial toxicity leading to symptomatic myopathy. In this study, three patients with telbivudine induced myopathy were enrolled in order to investigate the nature and pathogenesis of mitochondrial toxicity caused by long-term use of telbivudine. Methods: Clinical features, laboratory findings, muscle pathology, and quantitation of mitochondrial DNA were studied in three patients. Results: Patients presented with progressive muscle weakness with high serum creatine kinase levels. Light microscopic findings of muscle pathology showed ragged red fibers that reacted strongly with succinate dehydrogenase stain, but negative for cytochrome c oxidase activities. Electron microscopy revealed abnormal mitochondrial accumulation with rod shaped inclusions. The quantitative peroxidase chain reaction showed a depletion of mitochondrial DNA in skeletal muscle of the patients. Conclusions: Nucleoside analogues including telbivudine are potent inhibitors of viral DNA polymerases. However, they are not specific for viral DNA and can disturb mitochondrial replication at the same time. All nucleotide analogues should be used with close clinical observation in order to avoid development of mitochondrial myopathy.

• Journal of the Korean Society of Visualization
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• v.13 no.1
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• pp.35-42
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• 2015

CD4+ T-cell count determines the effectiveness for antiretroviral therapy (ART) in patients with human immunodeficiency virus (HIV). Although ART slows the progression of HIV to AIDS, rapid counting of CD4+ T lymphocytes with a drop of patient's blood sample is urgently needed to ensure timely ART treatment in rural areas. Recently point-of-care CD4 testing devices have been developed by using non-flow based imaging cytometer incorporated with a sample cartridge where CD4+ T cells are reacted with fluorescently tagged specific antibodies. Here we conducted an experimental study using a conventional fluorescence microscope-based imaging system to quantitate the interaction of CD4 antibodies with CD4+ T cells at different reaction conditions. We demonstrated that a fast and affordable point-of-care CD4 test is feasible with a far less amount of antibodies and a shorter incubation time compared with a conventional sample preparation protocol for flow cytometry. We also proposed a general method to evaluate and compare the detection limit across different CD4 counting platforms by using fluorescently labelled microbeads for intensity calibration.

• Korean Journal of Pharmacognosy
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• v.49 no.1
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• pp.70-75
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• 2018

Acer tegmentosum Maxim (ATM) has been used to treat hepatic disorders in traditional oriental medicine. However, there is little information about phytochemical constituents for quality control of ATM. In this study, we developed and established a simultaneous analytical method of the 10 marker compounds (three coumarins, 3 flavonoids, 1 lignan, 3 phenolics) in ATM using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Chromatographic separation of ten target analytes was achieved with a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$), using a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile with gradient elution. Identifications and quantitation of all analytes were performed using a Q-Exactive UPLC-MS/MS system. Correlation coefficients of the calibration curve for all analytes were ${\geq}0.9986$. The values of limits of detection and quantification of all analytes were 0.5-10.0 and 5.0-50.0 ng/mL, respectively. The established UPLC-MS/MS method successfully identified all target analytes in ATM, and the phytochemicals were 0.01-67.98 mg/g in its lyophilized water extract.

• Korean Journal of Veterinary Service
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• v.26 no.3
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• pp.199-202
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• 2003

Solid phase extraction(SPE) and matrix solid phase dispersion(MSPD) have been studied as preparation procedures for tetracyclines analysis by high-performance liquid chromatography(HPLC) in meat. The recovery range was 74${\sim}$98% for SPE, and 72${\sim}$93% for MSPD at spiked levels of 100ng/g for oxytetracycline(OTC), tetracycline(TC), chlortetracycline(CTC), and doxycycline(DC). The detection limits were 15${\sim}$78ng/g for SPE and 25${\sim}$84ng/g for MSPD, respectively. Analytical method was HPLC with UV detector. The purpose of this study was developing a practical, accurate and precise method for rapid extraction and quantitation of tetracycline residues in meat.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3611-3634
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• 2015

In this paper, we build a theoretical framework for quantitatively measuring and graphically representing the degrees of closeness centralization among performers assigned to enact a workflow procedure. The degree of closeness centralization of a workflow-performer reflects how near the performer is to the other performers in enacting a corresponding workflow model designed for workflow-supported organizational operations. The proposed framework comprises three procedural phases and four functional transformations, such as discovery, analysis, and quantitation phases, which carry out ICN-to-WsoN, WsoN-to-SocioMatrix, SocioMatrix-to-DistanceMatrix, and DistanceMatrix-to-CCV transformations. We develop a series of algorithmic formalisms for the procedural phases and their transformative functionalities, and verify the proposed framework through an operational example. Finally, we expatiate on the functional expansion of the closeness centralization formulas so as for the theoretical framework to handle a group of workflow procedures (or a workflow package) with organization-wide workflow-performers.

• Korean Journal of Food Science and Technology
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• v.6 no.3
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• pp.169-176
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• 1974

In order to investigate the producibility of aflatoxins by seven Aspergillus flavus strains isolated from deteriolated rice in Korea, polished rice was artificially inoculated and subjected to isolation and quantitation of the mycotoxin. It was proved that all strains were capable of producing aflatoxins, preferentially $B_1$ but no $G_1$ at all and their producibility was closely related to the color of culture media and chloroform extracts. The strain producing the most aflatoxin was A. flavus var. columnaris, excreting 1 ppm on rice. Aflatoxin $B_1$ was isolated and identified by thin-layer chromatography, ultraviolet absorption spectra and derivative formation of water and acetate adducts.

• Journal of Applied Biological Chemistry
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• v.50 no.4
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• pp.211-214
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• 2007

A solid-phase microextraction and gas chromatography-mass spectrometry utilizing $^{13}C$-formate as an internal standard for the determination of formate was proved to be applicable as a reliable quantitative method in several plants. We were the first to discover that trees contain larger pool sizes of formate than herbs. Our data also showed that the formate level of the leaves increased after the methanol-spraying, suggesting that methanol oxidation could convert formaldehyde into formate. In addition, drought and chilling led to the increase of endogenous formate in Arabidospsis thaliana. These results confirmed that formate is a universal stress signal in plants.

• Korean Journal of Pharmacognosy
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• v.26 no.2
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• pp.139-147
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• 1995

Crinum asiaticum var. japonicum is a wild plant growing only in Jeju-island, Korea, and in Japan. The whole part of this plant has been known to have the pharmacological actions such as analgesic, anti-inflammatory, platelet-aggregation inhibitory, antitussive, and expectorant. With these assumed actions, the leaves (Crinum folium) of this plant has been used in the folk remedies for arthritis and arthralgia. There is, however, no scientific evidences for the pharmacological actions of Crinum asiaticum var. japonicum. In the present study, the analgesic, anti-inflammatory, and platelet-aggregation inhibitory actions of Crinium folium were evaluated using writhing test, tail-flick test, carrageenin antiedema test, in vitro thromboxane $B_2$ quantitation assay and in vitro platelet aggregation test. In order to obtain the partially purified fraction whose pharmacological action is excellent, the methanol extract of Crinium folium was fractionated consecutively into four biological fractions such as ether, ethyl acetate, butanol, and water fractions and their pharmacological actions of the fractions were investigated. Putting our results together, Crinium folium, especially ethyl acetate fraction was proven to have significant analgesic, anti-inflammatory and platelet-aggregation inhibitory actions by inhibition of prostanoids biosynthesis as one of its mechanism of action.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.513-518
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• 1998

Beet curly top virus (BCTV) mutant has been constructed in vitro that contain G-to-T transversions at nucleotide 2727 within overlapping open reading frames (ORFs) L1 and L4. The mutations introduce termination codon in ORF L4 without affecting the amino acid encoded by ORF L1. When agroinoculated into Arabidopsis thaliana the mutant caused mild stunting and stem curling, but not the callus induction and hyperlasia on infected tissues of Sei-O ecotype. However, this mutant was not infectious on Col-O. Levels of single stranded DNA forms were similar in mutant and wild type BCTV infections. The DNA quantitation data showed that the DNA of BCTV-L4 mutant virus was accumulated in shoot tips, infection origin and roots with similar levels to those of wild type virus infected. Three tissues of asymptomatic ecotype Col-O also had as much as virus DNA from wild type virus infections. In both ecotypes infected with BCTV-Logan and BCTV-L4 mutant, root tissues contained more virus DNA than any other tissues by the Southern hybridization data. The results suggest that ORF L4 encodes a functional protein that is a major determinant of pathogenesis that might affect the hyperplastic response of the host to BCTV infection.