• Analytical Science and Technology
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• v.11 no.5
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• pp.353-359
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• 1998

Danazol, one of the IOC banned substances, is a synthetic steroid which stimulates the synthesis of cellular protein with multiple and diverse biologic effects. To confirm the androgenic effects of danazol, levels of eight endogenous steroids and its major metabolite in human urine were simultaneously analyzed by selected ion monitoring (SIM) of GC/MS after oral administration. The recovery range of this method was 71.59%~93.56% and the RSD values of precision and accuracy test were 1.87%~10.48% and 1.32%~11.25%, respectively. The limits of detection of most of the drugs were $0.01{\sim}0.05{\mu}g/mL$ and calibration was carried out using urine spiked with each endogenous steroid and ethisterone standard at a concentration of 0.1, 0.5, 1.0, 10, 20 and $50{\mu}g/mL$ and with $10{\mu}g/mL$ of internal standard. Correlation coefficients varied between 0.963 and 0.991. The endogenous steroid profiling is one of valuatle tool for decteation of anabolic steroids.

• Journal of the Korean Electrochemical Society
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• v.6 no.4
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• pp.255-260
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• 2003

The complex capacitance analysis was performed in order to examine the potential-dependent EDLC characteristics of porous carbon electrodes. The imaginary capacitance profiles $(C_{im}\;vs.\;log\lf)$ were theoretically derived for a cylindrical pore and further extended to multiple pore systems. Two important electrochemical parameters in EDLC can be estimated from the peak-shaped imaginary capacitance plots: total capacitance from the peak area and $\alpha_0$ from the peak position. Using this method, the variation of capacitance and ion conductivity in pores can be traced as a function of electric potential. The electrochemical impedance spectroscopy was recorded on the mesoporous carbon electrode as a function of electric potential and analyzed by complex capacitance method. The capacitance values obtained from the peak area showed a maximum at 0.3V (vs. SCE), which was in accordance with cyclic voltammetry result. The ionic conductivity in pores calculated from the peak position showed a maximum at 0.2 V (vs. SCE), then decreased with an increase in potential. This behavior seems due to the enhanced electrostatic interaction between ion and surface charge that becomes enriched at more positive potentials.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.520-524
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• 1995

ATP related compounds, ammonia, VBN, pH and sensory quality of shrimps were determined to evaluate quality changes during iced and frozen storage. ATP related compounds were determined by HPLC, ammonia by ammonia ion specific electrode, VBN by micro-diffusion method, pH by pH meter, sensory quality by multiple comparison test with 30 panelists. K value of ice stored shrimps gradually increased to 20% for 8 days, and then increased more rapidly, whereas that of frozen stored shrimps increased slowly for 7 months. Ammonia contents in ice stored shrimps increased slowly for 6 days and then rapidly after 8 days storage, whereas that in frozen stored shrimps increased slowly for 8 months. VBN contents in ice stored shrimps increased slowly for 10 days and then rapidly after 12 days. VBN contents in frozen stored shrimps slightly increased for 6 months. Sensory scores of taste and color of shrimps marked lowered values after 6 days storage in ice, and after 6 and 7 months frozen storage, respectively. Sensory flavor scores of stored shrimps had significant correlations with K value, ammonia, pH and VBN. These results indicated that ammonia contents in stored shrimps, rapidly determined by an ammonia electrode, could be used as a quality index of shrimps.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.218-226
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• 1995

Ion exchange equilibria in bulk and rhizosphere soil collected from peach seedlings were studied to find exchange equations that could be used in chromatographic models dealing with movement and distribution of fertilizer ammonium and exchangeable cations in soil profiles. Soil samples were equilibrated with mixtures of $NH_4Cl$, KCI, and $CaCl_2$ solutions and then extracted with $Sr(NO_3)_2$ solution to determine exchangeable cation compositions at equilibrium. Exchange data were fitted to Vanselow's, Gapon's, and Kerr's equations, but those formulations did not adequately describe the equilibria. An empirical equation of the form : ${\frac{\alpha_i^m}{a_j^n}}=K{\frac{(iX)^{mPi}}{(jX)^{nPj}}}$ which has an exponent on each of the exchangeable cation concentrations could describe the equilibria very well over the range of treatments. In this equation ${\alpha}^i$ and ${\alpha}^j$ are activities of cation i and j with valences m and n respectively. (iX) and (jX) are concentrations of exchangeable cations. Mole or equivalent fractions can be considered as the exchangeable ion concentration unit. Arbitrary constants $P_i$ and $P_j$, and distribution coefficient K can be found with multiple regression for the logarithmic form of the equation.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.84-89
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• 2019

To characterize the molecular structure of BzO-gal synthesized using Escherichia coli ${\beta}$-gal, NMR ($^1H$- and $^{13}C$-) spectroscopy and mass spectrometry of BzO-gal were conducted. $^1H$ NMR spectrum of BzO-gal showed multiple peaks corresponding to the galactosyl group, which is an evidence of galactosylation on BzOH. Five proton peaks around the aromatic region at ${\delta}_H$ 7.43 ~ 7.24 ppm and 2 peaks from ${\delta}_H$ 4.93 and 4.67 ppm were evidence of the presence of the benzyl group. Seven proton peaks at ${\delta}_H$ 4.32 ~ 3.46 ppm showed the presence of a monosaccharide and were indicative of galactosylation on BzOH. $^{13}C$ NMR spectrum also revealed the presence of 11 carbons suggestive of BzO-gal. The mass value (sodium adduct ion of BzO-gal, m/z = 293.0994) from mass spectrometry analysis of BzO-gal, and $^1H$ and $^{13}C$ NMR spectral data were in good agreement with the expecting structure of BzO-gal. We are expecting that through future study it will eventually be able to develop a new additive of low cytotoxicity.

• Analytical Science and Technology
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• v.21 no.5
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• pp.412-423
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• 2008

A procedure based on solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry has been developed for the simultaneous analysis of 55 basic drugs in equine urine. The test scope covers diversified classes of drugs including some ${\beta}$-blockers, ${\beta}$-agonists, antihypotensives, CNS stimulants, sedatives, tranquilizers, antidepressants, antihypertensives and so on. LC-MS/MS separation and quantification was carried out in positive electrospray ionization and multiple reaction monitoring (MRM) mode. Four different brands of mixed mode cation exchange SPE sorbents; UCT XTRACT$^{(R)}$ XRDAH, Supelco DSC-MCAX$^{(R)}$, Varian Bond Elut Certify$^{(R)}$ and Waters Oasis$^{(R)}$ MCX were compared. The UCT XTRACT$^{(R)}$ XRDAH sorbent provided the best results in the preconcentration of samples, yielding relative recoveries higher than 80% except for terbutaline (41.3%), salbutamol (71.5%), heptaminol (70.7%), phenylpropanolamine (66.3%). Detection limits of the target drugs provided by the proposed analytical procedure were between 0.2~8.3 ng/mL.

• Journal of the Korea Convergence Society
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• v.7 no.4
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• pp.45-50
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• 2016

This paper describes the development of smart sticks as walking assistance for elderly people that incorporate motion sensing, hear-beat sensing, data processing, and communication functions. Our sticks communicate with users' smart phones and upon a detection of falling-off, an alarm is generated and propagated to multiple guardians registered in advance. In addition, the sticks provide smart healthcare functionalities for elderly people thus suggest an health platform that is empowered by various health-related informations. The heartbeat sensors and motion sensors mounted on the sticks enable various additional functions. Our smart sticks are designed to function as stable walking assistance as well as to support elderly people by providing useful services in the convergence with information technologies.

• Journal of the Korean Chemical Society
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• v.44 no.1
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• pp.17-23
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• 2000

Electrodes of the polycationic film with electropolymerized $[Ru(v-bpy)_3]^{2+}$ having about 1:1 ratio of $PF6^-/ClO_4^-$as the doped counter ions, were modified with xylenol orange and diethylditbiocarbamate by ion exchange which had stability constant as 38.6 and 17.5 respectively. These electrodes were employed in the quantitative multiple determination of U(W) in solution. The working electrode of electrochemical cell for the analytical signal was Pt/p-$[Ru(v-bpy)_3]^{2+}$, ligand, U(VI) with Ag/AgCl reference elecrode. In the stripping voltammetry. electrode process was electron transfer controlled one and calibration curves at the ranges of $1.0{\times}10^{-3}{\sim}1.0{\times}10^{-7}$ M had excellent relationship as 0.99 and relative standard deviation as 5${\sim}$8%.

• Spatial Information Research
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• v.2 no.1
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• pp.3-14
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• 1994

The external diseconomy has been accelerated by the megaspatial structure of metropolis such as Seoul Capital Region(below SCR), Korea in which the more than 10 million populations inhabit. The main course for It could be elaborated by the overconcentration of the urban and regional function of various kinds. The study is performed to analyze quantitatively the status quo of the region as described above and proceed into forecasting the future population trend, the land use at location for the increment of regional population and to set the location of new towns in Seoul Capital Region System projected by the methods in computer algorithm of descriptive models such as the simple and multiple regress ion analysis models, the gravity model and the facility location on a plane model analysis. The goal and object ive of the metropolitan planning are to decentralize the regional growth management to the optimum degree, which will not hinder the economic growth of the region, but the result of the study is that we can not discourage the functional concentration of Seoul Capital Region and, we have to provide the region with the appropriate new towns.

• Molecular & Cellular Toxicology
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• v.1 no.3
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• pp.203-208
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• 2005

Thioacetamide (TA) is potent haptotoxincant that requires metabolic activation by mixed-function oxidases. Micrcarray technology, which is massive parallel gene expression profiling in a single hybridization experiment, has provided as a powerful molecular genetic tool for biological system related toxicant. In this study we focus on the use of toxicogenomics for the determination of gene expression analysis associated with hepatotoxicity in rat liver epithelial cell line WB-F344 (WB). The WB cells was used to assess the toxic effects of TA. WB cells were exposed to two concentrations of TA-doses which caused 20% and 50% cell death were chosen and the cells exposed for periods of 2 and 24 h. Our data revealed that following the 2-h exposure at the both of doses and 24-h exposure at the low doses, few changes in gene expression were detected. However, after 24-h exposure of the cells to the high concentration, multiple changes in gene expression were observed. TA treatment gave rise predominantly to up-regulation of genes involved in cell cycle and cell death, but down-regulation of genes involves in cell adhesion and calcium ion binding. Exposure of WB cells to higher doses of the TA gave rise to more changes in gene expression at lower exposure times. These results show that TA regulates expression of numerous genes via direct molecular signaling mechanisms in liver cells.