• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.288-294
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• 2011

BACKGROUND: Methylmercury is analyzed by HPLC-ICP/MS because of the simplicity for sample preparation and interference. However, most of the pre-treatment methods for methylmercury need a further pH adjustment of the extracted solution and removal of organic matter for HPLC. The purpose of this study was to establish a rapid and accurate analytical method for determination of methylmercury in fish by using HPLC-ICP/MS. METHOD AND RESULTS: We conducted an experiment for pre-treatment and instrument conditions and analytical method verification. Pre-treatment condition was established with aqueous 1% L-cysteine HCl and heated at $60^{\circ}C$ in microwave for 20 min. Methylmercury in $50{\mu}L$ of filtered extract was separated by a C18 column and aqueous 0.1% L-cysteine HCl + 0.1% L-cysteine mobile phase at $25^{\circ}C$. The presence of cysteine in mobile phase and sample solution was essential to eliminate adsorption, peak tailing and memory effect problems. Correlation coefficient($r^2$) for the linearity was 0.9998. The limits of detection and quantitation for this method were 0.15 and $0.45{\mu}g/kg$ respectively. CONCLUSION: Result for analytical method verification, accuracy and repeatability of the analytes were in good agreement with the certified reference materials values of methylmercury at a 95% confidence level. The advantage of the established method is that the extracted solution can be directly injected into the HPLC column without additional processes and the memory effect of mercury in the ICP-MS can be eliminated.

• Current Research on Agriculture and Life Sciences
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• v.30 no.2
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• pp.76-81
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• 2012

In this study the natural colorant was extracted from black bean seed coat in aqueous solution and used to dye silk and cotton fabrics. To obtain the optimal dyeing conditions it was examined at various dyeing condition (temperature, pH, time and liquor ratio). The dyeing behavior and the depths of shade which were evaluated in terms of K/S and CIELAB color difference values of the dyed and mordanted fabrics were also investigated. The dyeing fastness evaluated standard light and wash fastness tests. The obtained results were as follows ; The most K/S value of silk and cotton fabrics were obtained when the pH was 4.0 and 4.8, respectively and it increased slightly with dyeing time passes when the dyeing temperatures were at $40^{\circ}C$ and $60^{\circ}C$ but, it increased at $80^{\circ}C$. The color of silk fabrics changed from yellowish red to yellow at only Fe mordanting among various mordanting. Sn and Ti mordanting of silk fabric and only Ni mordanting of cotton fabric increased the $L^*$ values, but the others decreased. The light fastness of silk fabrics showed 4-6 grade without mordant, 4-5 grade with Al, 3-4 grade with Cu and Sn, and 2-3 grade with Fe as mordant, and that of cotton fabrics showed 1-2 grade without mordant, 2-3 grade with Fe, 2 grade with Cu, 1-2 grade with Al and Sn as mordants. All mordanting coluld not improve the light fastness of fabrics. Washing fastness(fade) of silk fabrics showed 2 grade without mordants and 2-3 grade with mordants and those of cotton fabrics showed 4 grade with Cu, 3 grade without mordant and with Al, Sn and Fe. All of the washing fastness(stain) of both fabrics showed 4-5 grade.

• KSBB Journal
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• v.23 no.4
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• pp.285-290
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• 2008

Various methods (OECD 301B, ISO 9439 and ASTM 5864) for biodegradability test of lubricants were reviewed, and a standard procedure was developed. Most lubrication products are released in rivers or sea then is degraded by microbial action in aerobic condition. Most international method are based on $CO_2$ evolution test. Inoculum obtained from a sewage disposal plant and test compound are cultivated in a mineral medium. Organic carbon of the test compound is degraded and oxidized through the enzymatic actions of inoculum, and ultimately mineralized to carbon dioxide. Biodegradability test conditions of lubricant oils were optimized. The highest biodegradability was achieved when the same medium as in ASTM 5864 and inoculum concentration of $10^4{\sim}10^5$ cell/L were used. The optimum standard materials were selected as aniline and sodium acetate. Additionally the effects of inoculum type on microbial growth and biodegradability were examined. Finally the standard operating procedure (SOP) for biodegradability test method was proposed.

• Membrane Journal
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• v.10 no.1
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• pp.39-46
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• 2000

To predict the absorption behavior of carbon dioxide on membrane contactor, an aqueous potassium carbonate solution as an absorbent. The reversible reactions of carbon dioxide with chemicals were considered, and the physicochemical properties of reaction rate constants, equilibrium constants, solubilities and diffusion coefficients were used as a function of concentration of carbon dioxide and the temperature. A non-wetted mode was also used as an operating condition of the membrane contactor. In these operation conditions, the effect of the following system parameters were studied : the concentration of potassium carbonate, the velocity of the absorbent and the pressure of the mixture gas. The absorption behavior of carbon dioxide caused by a facilitated transport was observed as the increment of the concentration of the absorbent. The absorption rate of carbon dioxide was increased as the absorbent velocity was increased. Furthermore, it was found that the pressure if the mixture gas and the reuse number of absorbent affect severely the absorption rate of carbon dioxide. The absorption behavior was successfully predicted by the computer simulation using the system parameters which are important for design and operation of the membrane contactor.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.223-233
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• 2010

The effects of extracellular polymeric substances (EPS) of Pseudomonas aeruginosa on adsorption and redox state alteration of dissolved As, Cr and U were investigated through batch experiments. Surfaces of bacterial cells were either vigorously washed or unwashed. Solutions of As(V), Cr(VI) and U(VI) were inoculated with the bacterial cells under no nutrient condition, and total aqueous concentrations and redox state alteration were monitored over time. No As adsorption occurred onto bacteria or EPS; however, unwashed bacteria reduced about 60% As(V) to As(III). Unwashed bacteria also led to removal of 45% total dissolved Cr and reduction of 64% Cr(VI). About 80% U(VI) was removed from solution with unwashed bacteria as well. Such electrochemical reduction of the elements was likely due to reducing capacity of EPS itself or detoxifying reduction of the bacteria which kept their viability under protection of EPS. The results indicated that bacterial biofilm may significantly control the redox state and subsequent mobility of As, Cr and U in natural geologic settings.

• Journal of the Korean Chemical Society
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• v.59 no.3
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• pp.225-232
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• 2015

A liquid chromatography-electrospray ionization-tandem mass spectrometry method (LC-ESI-MS/MS) was used for determining seven pesticides (2,4-dichlorophenoxyacetic acid, methomyl, aldicarb, 2-methyl- 4-chlorophenoxy- acetic acid, molinate, carbaryl and carbofuran) and two synthetic materials (quinoline and bisphenol-A) in surface water. The analytes were extracted using solid-phase extraction (SPE). The eluate was concentrated by nitrogen gas. 100 microliters of 30% (v/v) methanol aqueous solution were used to dissolve the residue and an aliquot of the reconstituted solution was directly injected into LC-ESI-MS/MS after the filtration using 0.2 μm polytetrafluoroethylene (PTFE) syringe filter. Under the established condition, the calibration curves of the analytes were linear with correlation coefficients of above 0.997. The quantification limit was 0.002~0.011 μg/L and the relative standard deviations were less than 16.4%. In addition, accuracy was in the range of 84~107% and the recoveries were values between 56.2 and 98.6%. In this study, the developed method was applied to the analysis of real surface water samples.

• Research in Plant Disease
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• v.20 no.1
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• pp.31-36
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• 2014

Alternative spraying was developed using fungicides and potassium phosphonate to control watermelon powdery mildew (WPM) caused by Sphaerotheca fusca under greenhouse condition. In 2010 trial, a total of 9 combinations of 6 fungicides which are legally registered in Korea and currently used on watermelon farms were tested for the control efficacy against WPM. Though the combination of chlorothalonil (Chl)-myclobutanil (My)-fenarimol (Fen)-hexaconazole (Hex) was the most effective (82.6%) in the first-year trial, it had the problem that My, Fen and Hex have the same mode of action. Therefore, in the second-year trial to improve the fungicide combination and to reduce fungicide application, fungicides and potassium phosphonate (P) combinations were tested for WPM control using 500 ppm aqueous potassium phosphonate solution which is both eco-friendly and showing different mode of action from the fungicides tested. The P-My-Fen-Hex applied at 10-day intervals provided relatively high control (75.6%), whereas Chl-My-Fen-P provided 31.8% control. To improve the control, fungicides and P were applied at 7-day intervals in the third-year trial. Though Chl-My-Fen-Hex provided the highest control (89.6%), P-My-Fen-Hex also provided relatively high control (83.5%) compared to 65.9 % control with Chl-My-Fen-P, which suggests that Chl-My-Fen-Hex could be replaced with P-My-Fen-Hex for WPM control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4927-4935
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• 2012

Turmeric is a medicinal herb with various pharmacological activities. Curcumin, demethoxycurcumin(DMC) and bisdemethoxycurcumin(BDMC) were extracted from turmeric by dipping and ultrasonic wave method. And extraction efficiency was identified using solid phase extraction(SPE). The extracted sample were simultaneously separated and analyzed from three kinds of commercial $C_{18}$ reversed-phase high performance liquid chromatography using water and acetonitrile as mobile phase with isocratic elution mode. Flow rate 1.0mL/min, injection volume $10{\mu}L$ and column oven temperature $40^{\circ}C$ at 425nm wavelength has been conducted. From the experimental results, the optimum mobile phase composition of water/acetonitrile 50/50vol% using RS tech column. It is evident that the amount of curcuminoids extracted(extraction time 4h) by 100% MeOH was higher than any aqueous MeOH composition. Finally, in 100% water extraction, the amount(mAU${\times}$mim) of curcuminoids extracted by SPE was 14.3 and 24.5 times respectively higher than ultrasonic wave and dipping method. The shown results can be applied as sources for pharmaceuticals and functional material.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.152-162
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• 2017

A hydrophilic coating solution was prepared by adding a silane coupling agent and a nano-inorganic oxide in aqueous surfactant solution to increase the efficiency of photovoltaic power generation due to the introduction of antifogging and antifouling properties on the glass surface of the solar cell module. Addition of $Ludox^{(R)}$, a nano-inorganic oxide, to 1% hydrophilic coating solution showed improved hydrophilicity and excellent antifogging effect regardless of $Ludox^{(R)}$ concentration. However, the antifouling effect on the glass surface was showed only when Ludox was added more than 10%. In the case of addition of 0.7% of hydrolyzed TEOS at pH 4, the antifogging effect was maintained as a result of the steam test as well as the antifouling effect even after the coated glass surface was rubbed 100 times with a wet Kimwipe. In addition, from the surface roughness ($R_q$) calculated using AFM data, the higher surface roughness with irregular surface shape was obtained with the higher concentration of TEOS. The addition of 0.7% of TEOS showed relatively high surface roughness and well organized surface condition which can help to improve transmittance of light. In conclusion, $Ludox^{(R)}$ is not required only for the antifogging property. However, at least 10% of Ludox should be added to show antifouling effect and 0.7% of TEOS should be added for good durability.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.4
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• pp.61-76
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• 2006

Purpose : This study examined the non-toxic and the anti-oxidative effect of Dioscoreae Rhizoma on PC12 cells. Sanyak(Dioscoreae Rhizoma; chinese yam, shan yao) is well-known for its curing power for kidney, lung, spleen. Tonifies and augments the spleen and stomach. Tonifies the lung gi and augments the kidney yin. Tonifies the kidneys and also stabilizes and binds. it also binds the essence and treats spermatorrhea, frequent urination, and vaginal discharge. We are therefore interested in whether Dioscoreae Rhizoma is capable of causing abnormal apoptosis processes, and whether this condition can be rectified through Dioscoreae Rhizoma herb treatment. Methods : We used aqueous extract to treat PC12 cells with different concentrations treated with a water or a MeOH extract of Dioscoreae Rhizoma (0, x10, x20, x40, x80). The MTT (3, (4, 5-dimethyl-thiazol) 2, 5-diphenyl-tetraxolium bromide) reduction assay was employed to quantify the differences in cell activity and viability. The Bax expression level was monitored using western-blotting techniques. The patterns of the changes in expression were scanned and analyzed. Results : Bax and GSK-3${\beta}$ promotes cell death and down-regulated during the development of the PC12 cells. This is indicated that Dioscoreae Rhizoma is capable of inducing apoptosis in PC12 cells. The induced cell death and significantly inhibited by Dioscoreae Rhizoma, which can be explained by the increase in the inhibition of Bax and GSK-3${\beta}$ expression. It was also shown that Dioscoreae Rhizoma inhibits the release of $H_2O_2$ and prevents lipid peroxidation. Furthermore, the accumulation of wild type Bax protein significantly downregulated in a dose-dependent manner upon treatment with Dioscoreae Rhizoma. Conclusion : In conclusion, Dioscoreae Rhizoma can induce apoptosis via a Bax-dependent pathway or GSK-3${\beta}$ dependent pathway in PC12 cells into anti-oxidant and protective effect.