• Biomedical Science Letters
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• v.7 no.3
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• pp.103-110
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• 2001

$\alpha$-Fetoprotein(AFP) is a good marker for the detection of several diseases such as hepatocellular carcinoma, gonadal germ cell tumor, gastric tumor, and Down's syndrome. In this study, we developed ELISA, using synthetic peptides corresponding to the epitopes of AFP. Five kinds of peptides were synthesized from AFP to produce antibodies in rats that recognize AFP in human plasma as well as amniotic fluid and do not cross-react with serum albumin. All five kinds of antibodies showed good reactivities with their peptide-keyhole limpet hemocyanin conjugates. Anti-synthetic peptide 1 (R-N-E-Y-G-I-A-S-I-L, 4-13) antibody, in particular, reacted well with AEP as well as synthetic peptide 1-KLH but not with human serum albumin. The binding affinity(Kd) was 2.7$\times$10$^{-9}$M for peptide 1 and 6.8$\times$10$^{-8}$M for AEP. The range for measurement of AFP was 10~1,000 ng/ml. The within-assay and between-assay coefficients of variance(CV) were 4.83% and 10.97%, respectively. In a sample of 31 sera and 33 amniotic fluids, there was a good correlation between AFP values determined in this assay and those in a commercial kit. These results indicate that the antibodies against synthetic peptides corresponding to the epitopes of AFP are highly specific to APP and synthetic peptide-based ELISA would be useful for the measurement of human AFP.

• Journal of the Korean Society for information Management
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• v.17 no.4
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• pp.157-170
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• 2000

CHROMA. a content-based image rctl-ieval syslem lhas inlroduced a perceptual color modcl, which can siinulatc the visual perceplual process of lhuman beings and eliminate ihe l~roblem ol condilional color variations. Th~s model Ihoweve~ rcgarded shadows and rcllcctions as u n k ~ ~ o u ~ i colors. and took no account of ihe inforclation which can bc gamed from them Th~s ~tudy atlempls Lo estnnale (he unbhown colors using i~ght~ng dil-cclions and lo prove that the process ol unknown colol eslimation can enhance the lperformance o l image retrieval syslems. With the ckperimcntal results, it was concludcd that thc model pmposcd in this study can enhance the perfomancc of content-based image retrieval systems using Lhe ]~ercepiual color model.

• Biomolecules & Therapeutics
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• v.12 no.3
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• pp.138-144
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• 2004

Therapeutic effect of a Kampo medicine, Choto-san, in patients with vascular dementia was demonstrated by a double-blind and placebo-controlled clinical trial. To clarify the therapeutic efficacy of Choto-san, anti-ischemic effect in mice, hypotensive effect in spontaneously hypertensive rats (SHR), anti-oxidative effects in vitro, and N-methyl-D-aspartate (NMDA) receptor-blocking activity using Xenopus oocytes were studied. (1) Pretreatment with Choto-san (0.75-6.O g/kg, P.O.) or a component herb Chotoko (Uncaria genus: 75 - 600 mg/kg, P.O.) prevented ischemia-induced impairment of spatial learning behaviour in mice. Indole alkaloids- and phenolic fractions extracted from Chotoko also improved significantly the learning deficit. (2) Subchronic administration of Choto-san (0.5 g/kg, p.o.) caused a significant hypotensive effects in SHR. (3) Choto-san, Chotoko, and the phenolic constituent, (-) epicatechin, significantly protected the NG108-15 cell injury induced by $H_20_2$ exposure in vitro and also inhibited lipid peroxidation in the brain homogenate. (4) Indole alkaloids, rhynchophylline and isorhynchophylline (1-100 uM), reversibly reduced NMDA-induced current in the receptor-expressed Xenopus oocytes. These results suggest that anti-vascular dementia effects of Choto-san are mainly due to the effect of Chotoko. From these results, it is possible to make a novel dietary supplement through several extraction steps from Chotoko.

• Mass Spectrometry Letters
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• v.11 no.1
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• pp.10-14
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• 2020

Riboflavin is a water-soluble vitamin, which serves as a precursor to flavin mononucleotide and flavin adenine dinucleotide. This study aimed to develop a simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for the quantification of riboflavin in the Beagle dog plasma. This method utilized simple protein precipitation with acetonitrile and ¹³C₄, ¹⁵N₂-riboflavin was used as an internal standard (IS). For chromatographic separation, a hydrophilic interaction liquid chromatography (HILIC) column was used with gradient elution. The mobile phase consisted of 0.1% (v/v) aqueous formic acid with 10 mM ammonium formate and acetonitrile with 0.1% (v/v) formic acid. Since riboflavin is an endogenous compound, 4% bovine serum albumin in phosphate buffered saline was used as a surrogate matrix to prepare the calibration curve. The quantification limit for riboflavin in the Beagle dog plasma was 5 ng/mL. The method was fully validated for its specificity, sensitivity, accuracy and precision, recovery, and stability according to the US FDA guidance. The developed LC-MS/MS method may be useful for the in vivo pharmacokinetic studies of riboflavin.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.279-283
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• 2001

The content and composition of tocopherol were analyzed in peanuts produced in Korea. The tocopherol assay was consisted of an extraction with n-hex-ane:isopropanol mixture followed by high pressure liquid chromatography with fluorescence detection. Tocopherol content was higher in leaves and seeds but lower in seed coats and shells. $\alpha$-/${\gamma}$- Tocopherol ratio was as low as 0.53 in seeds and as high as 22.5 in shells. Tocopherol content in seeds of nine varieties ranged from 142 to 220 ng/mg dry weight, and the $\alpha$-/${\gamma}$-tocopherol ratio from 0.40 to 0.75. Tocopherol content decreased by 18% but $\alpha$-/${\gamma}$-tocopherol ratio increased by 44% in roasted seeds. The results indicate that the level of tocopherol in Korean peanut varieties is moderate and the ratio of $\alpha$- to ${\gamma}$-tocopherol is low.

• Journal of Food Hygiene and Safety
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• v.8 no.4
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• pp.205-214
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• 1993

The monoclonal antibody to chloramphenicol(CAP) was produced to develop an enzyme-linked immunosorbent assay(ELISA) for residual CAP. An immunogen(CAP-BSA) was prepared by immunogen, antibody titer was measured by indirect ELISA. Spleen cells form the immunized mouse were fused with SP2/OAg14 myeloma cells. Among hybridomas selected in HAT media, 6 clones shown high antibody titer to CAP were subjected to cloning by limit dilution, and all of the monoclonal antibodies(MCA1, 2, 3, 4, 5, 7 and 9) produced by each clone were identified as IgG1 by ELISA isotyping analysis. Competitive ELISA condition was established by using the purified monoclonal antibody MCA1 as primary antibody and CAP-HSA conjugate as coating antigen. Standard curve of CAP(n=28) showed that the lowest detection limit of CAP is 20ng/ml level. The cross-reactivities of the 6 monoclonal antibodies showed that CAP sodium succinate. CAP base, P-nitrophenol, and p-nitrobenzyl alcohol were 89∼178, 0.050∼2.237, 0.056∼0.794 and 0.013∼7.939%, respectively. No cross-reactivities were observed with phenylalanine, tyrosine, glutamine, thiamphenicol, neomycin, streptomycin, gentamicin, sulfamethazine, sulfathiazole, chlortetracycline and p-aminobenzoic acid.

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.225-230
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• 2001

The aim of this study is to describe a usefulness of nuclear analytical technique in assessing and comparing the concentration levels through the analysis of uranium using human hair sample in the field of environment. A fission track detection technique was applied to determine the uranium concentration in human hair. Hair samples were collected from two groups of people - a) workers not dealing with uranium directly, and b) workers possibly contaminated with uranium. The concentration of $^{235}$ U for the first group varied from <1 to 39 ng/g and the second group can be estimated up to the level of $\mu$g/g. Radiographs of heavy-duty work samples contained high dense “hot spots” along a single hair. After washing in acetone and distilled water, external contamination was not totally removed. Insoluble uranium compounds were not completely washed out. The (n, f)- radiography technique, having high sensitivity, and capable of getting information on uranium content at each point of a single hair, is an excellent tool for environmental monitoring.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.647-651
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• 2002

An LC/MS/MS method for the simultaneous determination of a neuroprotective agent for ischemia-reperfusion damage, KR-31378 and its N-acetyl metabolite KR-31612 in human plasma was developed. KR-31378, KR-31612 and the internal standard. KR-31543 were extracted from human plasma by liquid-liquid extraction. A reverse-phase HPLC separation was performed on Luna phenylhexyl column with the mixture of acetonitrile-5 mM ammonium formate (55:45, v/v) as mobile phase. The detection of analytes was performed using an electrospray ionization tandem mass spectrometry in the multiple reaction monitoring mode. The lower limits of quantification for KR-31378 and KR-31612 were 2.0 ng/ml. The method showed a satisfactory sensitivity, precision, accuracy, recovery and selectivity.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.613-616
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• 2002

A high-performance liquid chromatographic method has been developed for the separation and quantification of chrysin and synthetic chrysin derivatives (12 chrysin alkyl and 7 chrysin acyl derivatives). The chromatography was performed using a $Nova-Pak^{\circledR}C_{18}$ column. A RP-HPLC was performed by using a binary mixture (MeOH-10 mM H$_3$PO$_4$) as a mobile phase, and the column temperature was maintained at room temperature. A flow rate was 1.0 ml/min, and the effluent was monitored at a wavelenth of 280 nm. The retention times for chrysin acyl and alkyl derivatives were within 10 minutes and 20 minutes, respectively. The absolute recovery of samples were all over 96%. The detection limits were 0.1~18 ng at S/N = 3 ratio.

• The Journal of the Acoustical Society of Korea
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• v.31 no.6
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• pp.353-358
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• 2012

This paper describes acoustic phonetic parameters for detecting nasal place in a knowledge-based speech recognition system. Initial acoustic phonetic parameters are selected by studying nasal production mechanisms which are radiation of the sound through the nasal cavity. Nasals are produced with differing articulatory configuration which can be classified by measuring acoustic phonetic parameters such as band energy ratio, band energy differences, formants and formant differences. These acoustic phonetic parameters were tested in a classification experiment among labial nasal, alveolar nasal and velar nasal. An overall classification rate of 57.5% is obtained using the proposed acoustic phonetic parameters on the TIMIT database.