• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.137-141
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• 1997

We evaluated Immunochromatographic assay kit to screen HBsAg in human serum. When the reference HBsAg was applyed to ICA, HA and EIA kits, the limit of detection for HBsAg were found out to be 4, 2 and 0.25 ng/ml respectively. But ICA kit required 5 minutes to read the result whereas HA and EIA kit more than one hour. The sensitivity was 97% (29 of 30 samples) and the specificity 100% (45 samples) compared with conventional EIA. The ICA kit needs no instrument or machine to perform the test contrary to the conventional methods. Therefore, this rapid and sensitive ICA kit can be used for HBsAg-screening, especially in the emergency room and in the scene of the accident.

• Smart Structures and Systems
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• v.14 no.3
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• pp.377-395
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• 2014

Vibration-based fault detection and condition monitoring of rotating machinery, using statistical process control (SPC) combined with statistical pattern recognition methodology, has been widely investigated by many researchers. In particular, the discrete wavelet transform (DWT) is considered as a powerful tool for feature extraction in detecting fault on rotating machinery. Although DWT significantly reduces the dimensionality of the data, the number of retained wavelet features can still be significantly large. Then, the use of standard multivariate SPC techniques is not advised, because the sample covariance matrix is likely to be singular, so that the common multivariate statistics cannot be calculated. Even though many feature-based SPC methods have been introduced to tackle this deficiency, most methods require a parametric distributional assumption that restricts their feasibility to specific problems of process control, and thus limit their application. This study proposes a nonparametric multivariate control chart method, based on multiscale wavelet scalogram (MWS) features, that overcomes the limitation posed by the parametric assumption in existing SPC methods. The presented approach takes advantage of multi-resolution analysis using DWT, and obtains MWS features with significantly low dimensionality. We calculate Hotelling's $T^2$-type monitoring statistic using MWS, which has enough damage-discrimination ability. A bootstrap approach is used to determine the upper control limit of the monitoring statistic, without any distributional assumption. Numerical simulations demonstrate the performance of the proposed control charting method, under various damage-level scenarios for a bearing system.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.33-38
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• 2008

In veterinary medicine amitraz has been used as an insecticide to eliminates mites, lice, and ticks in dogs, cats, goats, swine and cattle. The objective of present study was to developed an analytical method using one-step extraction and determination of the amitraz in veterinary drugs by liquid chromatography (LC). The amitraz was analyzed by LC equipped with Waters XTerra RP18 ($4.8{\times}250mm;\;5{\mu}m;\;Waters,\;USA$) analytical column, using 75% acetonitrile (acetonitrile/D.W; 75/25) at 1.0 ml/ min. The UV-VIS detection of amitraz was made at 290 nm. Calibration graphs were linear with very good correlation coefficients ($r^2>0.9999$) from $80{\sim}120{\mu}g/ml$. The limit of detection was $0.09{\mu}g/ml $ and limit of quantification was $0.27{\mu}g/ml $. The method showed good intra-day precision (CV 0.05~0.09%) and inter-day precision (CV 0.06~0.18%).

• Food Science and Biotechnology
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• v.17 no.3
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• pp.508-513
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• 2008

Erythromycin has been used to treat Streptococosis, Edwardsiel1osis, Vibriosis, Bacterial enteritis in the cultured fish. In this study, a rapid and effective erythromycin analysis method with new sample treatment protocol and liquid chromatography/tandem mass spectrometry (LC/MS/MS) system for fish products was developed. For the erythromycin extraction from fish muscle, the solvent mixture composed of 0.2% meta-phosphoric acid and methanol (6:4) showed good recovery rate, and the optimum extraction solvent volume was 20 mL. Erythromycin detection using LC/MS/MS were carried out under electro spray ionization (ESI) positive condition and erythromycin mass value 576.2 and 157.9. And the detection limit of the established method was 0.005 mg/kg in fish products. The recovery rate of the developed method applied to the fish species were as following, olive flounder, $87.6{\pm}5.0%$; black rockfish, $87.2{\pm}6.4%$; eel, $85.2{\pm}4.8%$; and rainbow trout, $86.0{\pm}6.2%$. In the established method in this study, the correlation of coefficient values ($R^2$) of erythromycin calibration curve (n=11) was 0.9998.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.488-496
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• 2002

SPME techniques have proven to be very useful tools in the analysis of wide VOCs in the air. In this study, we estimated VOCs in ambient and workplace air using a Tedlar ba /SPME/GC/MS system. The calibration curve was set to be linear over the range of 1-30 ppbv. The detection limits ranged from 10 pptv to 0.93 ppbv for all VOCs. Reproducibility of TO-14 target gas mixtures by SPME/GC/MS averaged at 8.8 R.S.D (%). Air toxic VOCs (hazardous air pollutants, HAPs) containing a total of forty halohydrocarbons, aromatics, and haloaro-matic carbons could be analyzed with significant accuracy, detection limit and linearity at low ppbv level. Only reactive VOCs with low molecular weight, such as chloromethane, vinylchloride, ethylchloride and 1,2-dichloro-ethane, yielded relatively poor results using this technique. In ambient air samples, ten VOCs were identified and quantified after external calibration. VOC concentration in ambient and workplace air ranged from 0.04 to 1.85 ppbv. The overall process was successfully applied to identify and quantify VOCs in ambient/workplace air.

• Korean journal of food and cookery science
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• v.31 no.1
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• pp.1-8
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• 2015

Organic acids are known as natural sanitizers. We examined the sanitizing effects of five organic acids (acetic acid, propionic acid, citric acid, malic acid, and lactic acid) and their persistence on three pectinolytic yeast strains isolated from decayed citrus, and the persistence of their sanitizing effects was determined during storage at $4^{\circ}C$ and $16^{\circ}C$. The 7~8 log CFU/mL of the mixed three yeast mixture was exposed to various concentrations of each organic acid for 1 min. The yeast mixtures decreased under detection limit(1 log CFU/mL) in 1% of acetic acid, followed by in 3% of propionic acid with the reduction of 5 log CFU/mL. The citric acid, malic acid, and lactic acid decreased the number of yeasts under detection limit at 7.5%. When treated with deionized water and 1~5% of organic acids were treated on the surfaces of citrus contaminated by yeasts, total numbers of the yeasts decreased under detection limit(3 log CFU) at 5% of acetic acid and 4 log CFU/piece at 5% propionic acid compared with deionized water. When treated with acetic acid and propionic acid on the stem ends of the contaminated citrus, total numbers of the yeasts significantly decreased 0.5 log CFU/piece at 3% of both organic acids. During storage at $4^{\circ}C$ and $16^{\circ}C$ for 20 days, total number of yeasts significantly decreased at 2% acetic acid compared with deionized water. This study suggested that organic acids could be used to sanitize microbial contaminants from citrus for storage and transportation.

• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.82-86
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• 1997

Pharmacokinetics of a new capsaicin analog, DA-5018 were evaluated after a subcutaneous injection or topical application of $[^{14}C]$--labelled or unlabelled DA-5018 to rats and rabbits. After subcutaneous injection of $_{14}$c-labelled or unlabelled DA-5018, 0.5 mg/kg (equivalent to DA-5018) to rats, the plasma total activity peaked at 2 hr with the terminal half life of 5.34 hr, however, unlabelled-DA-5018 peaked at 1 hr with the terminal half life of 1.26 hr. Moreover, the AUC (0.726 versus 0.2337g hr/ml) and MRT (7.82 versus 3.55 hr) increased significantly based on total radioactivity compared with intact DA-5018. Above data indicated that DA-5018 is extensively metabolized in rats and the terminal half- life of the metabolite(5) had a longer half-life than that of DA-5018. The cumulative percentages of biliary excretion of dose after subcutaneous injection of $[^{14}C]$DA-5018 was 40.2%, however, the value was only 2.14% when unlabelled DA-5018 was injected. After topical application of 0.1% or 0.3% $_{14}$C-labelled or unlabelled DA-5018 cream, 500 mg/kg to rats, the plasma and tissue concentrations except applied skin were under the detection limit. After consecutive 7 days topical application of unlabelled DA-5018, 0.1% and 0.3% cream to rats, the plasma concentrations were also under the detection limit. But the urinary excretion of DA-5018 was significantly increased by repeated topical administration. After topical application of unlabelled DA-5018, 0.1% and 0.3% cream to rabbits, the plasma and urine concentrations were under the detection limit. Above data indicated that the skin permeation of DA-5018 was lower and the metabolism of DA-5018 was higher in rabbits than that in rats.

• Journal of Preventive Medicine and Public Health
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• v.32 no.2
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• pp.155-161
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• 1999

Objectio ostinato the carcinogenic risks from the ingestion of some carcinogenic pesticides (CPs) in vegetables sampled at a local agricultural product market in Seoul. Methods: After applying a hazard identification step, we selected four pesticides, such as DDT, dieldrin, folpet, and heptachlor epoxide, for this risk assessment. Concentrations of each pesticide were measured from randomly sampled vegetables. In order to estimate the human exposure levels, we combined the concentration of pesticides in the vegetables with consumption rate of those vegetables. Three scenarios were hypothesized for human exposure assessment. Scenario I was the most conservative which supposed the undetected CPs would be the detection limit values. Scenario II was assumed that the undetected CPs would be a half of the detection limit values, and finally scenario III merely considered only values greater than the detection limit values. We finally presented the estimated carcinogenic risks on the basis of the traditional risk assessment procedure suggested by U.S. EPA. Results: Pesticides including DDT, dieldrin, folpet and heptachlor epoxide were detected in 9 samples (6%) in the range of $0.0006\sim0.09ppm$. The daily intake levels of carcinogenic pesticides were estimated in the range of $0.0009\sim0.0079{\mu}g/day$. As we expected, excess cancer risks based on scenario I was also the highest $(1.1\times10^{-8}\sim5.5\times10^{-5})$. Conclusions: We found that the estimated risks from the pesticides we investigated were not serious. We, however, propose that a continuos monitoring is needed to make sure for the protection of public health.

• Analytical Science and Technology
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• v.14 no.6
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• pp.486-493
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• 2001

The effect of SIMS analysis conditions such as mesh grid, offset voltage and ion species on the in-depth profile for bismuth titanate thin film was examined in terms of charging effect and detection limit. The results shows that the use of offset voltage -40 V reduces the charging effect and the detection limit. The employment of mesh grid in sample preparation leads to the reduction of the charging effect in small amount, but deteriorate the detection limit. Utilization of primary $O^-$ ion for SIMS analysis of bismuth titanate thin film showed almost the same effect as using offset voltage -40 V. However, it takes approximately triple acquisition time than using $O_2{^+}$ ion due to the poor beam current of the source in the experiment.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.22-25
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• 1998

These studies were conducted to develope analysis method of herbicide quizalofop-ethyl by Gas Liquid Chromatography(GLC) and Enzyme-Linked Immunosoment Assay(ELISA) in soil and plant. Quizalofop produced by hydrolysis of quizalofop-ethyl was conjugated with bovine serum albumin(BSA). Quizalofop antibody was developed in rabbits by using BSA conjugation. Antibody titer, incubation temperature, and incubation time was 32,000, $37^{\circ}C$ and 4hours respectively. Minimum detection limit of quizalofop-ethyl by ELISA was 5ppb. Quizalofop-ethyl recovery from soil by ELISA was more than 95percent. Minimum detection limit of quizalofop-ethyl by GLC was 5ppb. Quizalofop-ethyl recovery from soil by GLC was from 89 percent to 100 percent. Minimun detection limit of quizalofop-ethyl by HPLC was 100ppb. Quizalofop-ethyl recovery from soil by HPLC was 89.6 percent.