• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.5
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• pp.524-532
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• 2003

The change of interactions of anionic surfactants, sodium dodecyl sulfate(SDS) and sodium tetradecyl sulfate(575) in the presence of electrolytes, to the chitosan-based polyelectrolyte(sol＇n and gel phase) were studied. The chitosan gel used in this study were crosslinked with epichlorohydrin(ECH). Binding isotherms were determined by potentiometric technique using a surfactant ion selective solid-state electrode and the results were represented by using the sequence generating function(SGF) method. The results of binding isotherm were shown comparatively high cooperativity. The addition of electrolytes in the chitosan/SDS system resulted in a shift of the binding to higher free surfactant concentration because of screen effect by the electrolytes. Degree of binding of chitosan gel was higher than that of chitosan sol＇n. And also a conformational phase transition of the chitosan gel in the presence of electrolytes has been investigated.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.61.3-61
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• 2001

Field screening for pollutants has been a target of instrumental development for number of years. An electronic nose can be of substantial benefit to rapidly localize the spatial extent of a pollution or to find pollutant source. Although an electronic nose cannot separate complex composition into the whole spectrum of present volatile organic compound(VOC) in pollutants such as Gas chromatography(GC), qualitative and semi-quantitative chemical characterizations are rapidly available on site at a low cost using the optimum sensory system and pattern recognition algorithm based on neural network.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.116-120
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• 2022

In this paper, we developed a paper blood glucose sensor that can minimize the effect of hematocrit. The paper blood glucose sensor has the advantage of being very simple in its production process as it is manufactured with only three printing processes on the top of the paper substrate. This glucose sensor consists of a total of six electrodes, including blood glucose measurement electrodes, hematocrit measurement electrodes, strip detection electrodes, and blood detection electrodes. A paper blood glucose sensor measures hematocrit with electrodes formed on the same sensor substrate when measuring blood glucose concentration, and compensates for the effect of hematocrit in real time to enable accurate blood glucose measurement.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.72-76
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• 2010

We have developed the bio-electrode measuring the variance of the amount of acetylcholine affected by residual pesticide. The working electrode of the biosensor was made by combination of cobalt phthalocyanine and carbon organic compounds. The biosensors were constructed by screen-printing method. The principle of working electrode is similar to thiocholine sensor. We have fabricated the biosensor using standard screen printing method. Generally, the biosensor made by printing method formed thick film biosensor. When the electrodes were made by electrochemical cells, the generation of current by the addition of enzyme substrate was inhibited by standard solutions of organo-phosphate pesticides. The detection limit of sensor is about 0.5 $\mu{g}/L$ for carbofuran. We could improve the responsibility of the sensor by controlling the cobalt phthalocyanine and thiocholine concentration ratio. Also we have tested the EPN and Chlorpyrifos pesticides and found that the biosensor is applicable to fast determination of residual pesticides.

• Toxicological Research
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• v.16 no.2
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• pp.109-116
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• 2000

The purposes of our study were to optimize the conditions of the screening and testing methods for endocrine disruptors, to characterize these assays using several compounds with well-defined endocrine activity, and to compare the sensitivity between these assays currently undergoing validation. Two in vitro test systems, MCF-7 cells proliferation (E-screen assay) and competitive binding to estrogen receptors (ER) were selected to evaluate the estrogenic effects. 17$\beta$-Estradiol (E2) and diethylstilbestrol (DES) were used as a positive control in vitro test. Also, E2 and ethinyl estradiol (EE) were used as a positive control in vivo uterotrophic assay. In in vitro test, E2 and DES showed a strong estrogenic response at concentration of 1.0 nM. In uterotrophic assay, E2 (0.3 $\mu\textrm{g}$/kg) and EE (0.3 $\mu\textrm{g}$/kg) produced a significant increase in uterus and vagina weight in both immature and ovariectomized rats. Although we did not com-pared the specificity between in vivo and in vitro assays, these assay systems may serve as a good tool for endocrine disruptors screening methods. Our data indicate that these assay systems exhibit some difference in their sensitivity to the same estrogenic compounds. Therefore, as a first rapid screening assay for estrogenic activity qf unknown chemicals, at least two assay systems should probably be carried out with a view of high sensitivity and standardization conditions. Also, a careful validation tests are necessary to obtain a reasonable degree of reproducibility.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.201-208
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• 2015

We investigated the pollution levels of $PM_{2.5}$ at Wangsimni station at which four subway lines (Line 2, Line 5, the Jungang line, and the Bundang Line) are simultaneously under the operation. The analysis of $PM_{2.5}$ was made for the period of 1~ 11 Nov. 2014. The results of our field campaign were analyzed to assess the effects of various factors and conditions on the $PM_{2.5}$ pollution (such as installation of the screen door, density of floating population, weekdays and weekend, and the depth of platforms). The mean concentrations of $PM_{2.5}$ in each subway line of the Wangsimni station was measured as: the line 2 ($22.5{\mu}g/m^3$) ; the line 5 ($18.3{\mu}g/m^3$) ; the Jungang line ($31.8{\mu}g/m^3$); and the Bundang line ($32.2{\mu}g/m^3$). Based on the detailed analysis of $PM_{2.5}$ pollution at four subway lines, we aimed to provide some perspectives on reducing the concentration of ultrafine particles in a highly populated urban area.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.50-56
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• 2010

The multi-wall carbon nano-tube composite mixed with carbon paste electrode presented more sensitive and selective amperometric signals in the oxidation of glucose than general screen-printed carbon electrodes(SPCEs). Redox mediators to transport electrodes from enzyme to electrodes are very important part in the biosensor. A novel osmium redox complex was synthesized by the coordinating pyridine group containing primary amines which were electrochemically immobilized onto the MWCNT-SPCEs surface. Electrochemical studies of osmium complexes were investigated by cyclic voltammetry, chronoamperometry. The surface coverage of osmium complexes on the modified carbon nano-tube electrodes were significantly increased at 100 time (${\tau}_0=2.0\;{\times}\;10^{-9}\;mole/cm^2$) compared to that of the unmodified carbon electrodes. It's practical application of the glucose biosensor demonstrated that it shows good linear response to the glucose concentration in the range of 0-10 mM.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.374-383
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• 2012

In this study, we have observed the airborne radon levels in the subway cabins before and after platform screen doors (PSD) installation. The measurements have been conducted at Seoul metropolitan subway lines in 2008, 2009 and 2010. The mean concentration of the radon inside subway cabins were increased by approximately 53% from $20.1Bq/m^3$ to $30.8Bq/m^3$ by installing PSD. After PSD installation, measured values for the different lines were rather different, and varied between 8.2 and $76.5Bq/m^3$. And mean radon concentrations were in the decreasing order for subway lines 5, 6, 7, 8, 3, 4, 2, 9 and 1. It was also found that the indoor radon concentrations in the subway cabins were highly dependent on the management approach of a ventilation system at the subway stations. By assuming an average of $720\;h\;year^{-1}$ and $2,880\;h\;year^{-1}$ spent in subway cabin, effective doses to passengers and employee were estimated. The expected annual effective dose, in case of an equilibrium factor of 0.4, were $0.07mSv\;y^{-1}$ and $0.26mSv\;y^{-1}$, respectively.

• Journal of Sasang Constitutional Medicine
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• v.19 no.2
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• pp.170-178
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• 2007

1. Objective This study was aimed to screen the potential antitumor activity of one kinds of Korean medicinal herb extracts against cancer cell lines and to evaluate the growth inhibition effect of L-1210 and S-180 cancer cell lines. 2. Methods It confirmed Anemarrhena asphodeloides extracts to screen the potential antitumor activity. Then, it was extracted with 4 kinds of solvents ; hexane, ethyl acetate, butanol and $H_2O$, and the Growth inhibition effect of these extracts were determined against cancer cell and normal cell. The results were as follows : The IC50(50% inhibitory concentration) values of Anemarrhena asphodeloides extracts were shown to be $253{\mu}g/ml$ against L-1210 cell lines. The IC50 values of ethyl acetate extracts were shown to be $915{\mu}g/ml$ against L-1210 cell lines. The IC50 values of butanol extracts were shown to be $52.3{\mu}g/ml$, $485{\mu}g/ml$ against L-1210, S-180 cell lines, respectively. The butanol extracts were more selectively effective than other extracts to cancer cell lines. 3. Conclusion From these data, it could be concluded that the Anemarrhena asphodeloides extracts to the Growth inhibition effect of L-1210 and S-180 cancer cell lines.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.568-572
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• 2001

To screen antioxidative and whitening effects of some medicinal plants, 70% ethanol extracts were tested for their electron donating abilities to DPPH ( ${\alpha}$, ${\alpha}$-diphenyl- ${\beta}$-picrylhydrazyl) and inhibitory activities against lipid peroxidation, and tyrosinase inhibition in vitro. The electron donating activities of 70% ethanol extracts at the concentration of 100 $\mu\textrm{g}$/ml were in the order of Forsythiae fructus > Polyporaceae > Glycyrrhizae radix > Schizandrae fructus > Ramulus mori > Carthami semen. The order was Forsythiae fructus > Carthami semen > Schizandrae fructus > Polyporaceae > Glycyrrhizae radix when tested at 10 $\mu\textrm{g}$/ml, indicating that the activities depend on the concentration. The electron donating activities of Forsythiae fructus and Carthami semen at the concentration of 1 $\mu\textrm{g}$/ml were 37% and 31% respectively. Lipid peroxidation inhibitory activities were in the order of Artemisia messerschimidtiana > Glycyrrhizae uadix > Rehmaniae radix > Ramulus mori. Tyrosinase inhibitory activities were in the order of Ramulus mori > Artemisia messerschimidtiana > Oyster mushroom. The results suggest that Forsythiae fructus, Artemisia messerschimidtiana and Ramulus mori could be used as materials for anti-skin aging functional cosmetics.