• Journal of Korean Biological Nursing Science
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• v.7 no.1
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• pp.47-56
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• 2005

nm23-H1 gene expression has been inversely correlated with tumor metastatic potential in certain tumors including melanomas, breast carcinomas, and hepatocellular carcinomas. However, its role with respect to the invasive behavior of central nervous system tumors has scarcely been addressed Because cell motility and invasion plays an essential role in metastatic dissemination, we have studied whether motile human glioma cell(U87MG) transfected with nm23-H1 complementary DNA have any alterations in their ability to migrate and invade. There was no significant changes in the shape and size of the cells following nm23-H1 transfection. The role of nm23-H1 in glioma migration and invasion have been evaluated by in vitro simple scratch technique and brain slice invasion model Basal migration ability of nm23-H1 transfectants cell(U87MG-pEGFP-nm23) were lesser than U87MG. Accordingly, U87MG-pEGFP-nm23 didn't migrate away apparently from the tumors implanted site comparing U87MG in brain slice invasion model. These results suggest that nm23-H1 may play an important role in suppressing the human glioma migration and invasion.

• Polymer(Korea)
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• v.30 no.1
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• pp.45-49
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• 2006

In this study, it was investigated on the boron separation ken synthetically prepared seawater. ion exchange resin used in the experiments was Amberlite IRA 743, containing glucamine functional group. The experiments were carried out as a function of the conditions of the pH, boron initial concentration and temperature of seawater in a batch reactor. As a result, optimum conditions for boron adsorption were at pH 8.5 and 313 K, respectively. The adsorption rate was increased very fast with increasing the temperature, but decreased with increasing the initial concentration of boron. Also, the kinetics for boron adsorption applied the pseudo-second order model, as follows: $$\frac{X}{1-X}=780[C_0]^{-1.65}t^{1.48}\;exp\;({-\frac{17883}{RT}}\)\;;\;pH8.5$$

• Progress in Superconductivity
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• v.12 no.2
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• pp.124-128
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• 2011

We have developed a high-$T_C$ SQUID magnetometer system to measure magnetocardiograms of laboratory rats. White noise of the measurement system was about 50 fT/$Hz^{1/2}$ when measured in a magnetically shielded box. We optimized the measurement position to obtain clear MCG wave from rat's small heart by using grid measurements. With the optimization, the MCG signal was successfully detected with the peak amplitude of about 50 pT. We could observe well defined P-, QRS-, and T-wave from the rat MCG. The results suggest that the developed system has a strong potential to monitor the progress of heart disease model using laboratory rat.

• Journal of Korean Society on Water Environment
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• v.35 no.5
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• pp.432-438
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• 2019

The purpose of this study is to predict Trophic Diatom Index (TDI) in tributaries of the Han River watershed using the random forest algorithm. The one year (2017) and supplied aquatic ecology health data were used. The data includes water quality(BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, water temperature, DO, pH, conductivity, turbidity), hydraulic factors(water width, average water depth, average velocity of water), and TDI score. Seven factors including water temperature, BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, and average water depth are selected by the Correlation Feature Selection. A TDI prediction model was generated by random forest using the seven factors. To evaluate this model, 2017 data set was used first. As a result of the evaluation, $R^2$, % Difference, NSE(Nash-Sutcliffe Efficiency), RMSE(Root Mean Square Error) and accuracy rate show that this model is compatible with predicting TDI. To be more concrete, $R^2$ is 0.93, % Difference is -0.37, NSE is 0.89, RMSE is 8.22 and accuracy rate is 70.4%. Also, additional evaluation using data set more than 17 times the measured point was performed. The results were similar when the 2017 data set were used. The Wilcoxon Signed Ranks Test shows there was no statistically significant difference between actual and predicted data for the 2017 data set. These results can specify the elements which probably affect aquatic ecology health. Also, these will provide direction relative to water quality management for a watershed that must be continuously preserved.

• Journal of Environmental Impact Assessment
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• v.23 no.3
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• pp.187-196
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• 2014

The objective of this study is to evaluate and analyze Osu stream watershed water environment system. The data were collected from January 2009 to December 2011 including water temperature, pH, DO, EC, BOD, COD, TOC, SS, T-N, T-P and discharge. The data were used for principle component analysis and factor analysis. The results are as followes. The primary factors obtained from both the principal component analysis and the factor analysis were BOD, COD, TOC, SS and T-P. Once principal component analysis and factor analysis have been performed with the collected data and then the results will be applied to both simple regression model and multiple regression model. The regression model was developed into case 1 using concentrations of water quality parameters and case 2 using delivery loads. The value of the coefficient of determination on case 1 fell between 0.629 and 0.866; this was lower than case 2 value which fell between 0.946 and 0.998. Therefore, case 2 model would be a reliable choice.The coefficient of determination between the estimated figure using data which was developed to the regression model in 2012 and the actual measurement value was over 0.6, overall. It can be safely deduced that the correlation value between the two findings was high. The same model can be applied to get TOC concentrations in future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.2
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• pp.173-183
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• 2021

Objectives: This study evaluated the skin permeability of lawsone in henna hair dyes to understand the exposure characteristics of henna hair dyes in the human body. It examined the protective effects of protectants by applying protectants A, B, and C to test skin. Methods: Skin absorption tests were conducted using Franz diffusion cells according to OECD test guideline 428. After applying one kind of natural henna hair dye and chemical henna hair dye, respectively, to a standardized pig skin model, samples of receptor fluid were collected at 1h, 3h, 6h, and 24h. The skin permeation of lawsone was determined using HPLC. After the skin absorption experiment, the skin to which hair dye was applied was analyzed to determine the residual amount of lawsone in the skin. Results: The cumulative permeation of both natural and chemical henna hair dyes increased over time, and the natural henna hair dye had a flux value (t=3.194, p<.05) high both in the K_p value (t=3.207, p<.05) and the residual amount (t=22.701, p<.001). For skin treated with a protectant, the cumulative permeation of natural henna hair dye 24h control and the cumulative permeation of protectant A, B, and C increased over time. Flux and K_p values were in the order control > protectant A > protectant C > protectant B. The residual amount (F=4.469, p<.05) was in the order of protectant C > protectant A > protectant B > control. At 3h, the dye application time of natural henna hair dye, the lawsone flux value (F=4.454, p<.05) and K_p value (F=4.455, p<.05) were higher in the control group than in the protectant groups. The 24h cumulative permeation of the chemical henna hair dye increased with time in both the control and the protectant groups, and the flux and K_p values were in the order of protectant A > protectant C > protectant B > control. The residual amount (F=7.901, p<.01) was in the order of protectant B > protectant A> protectant C > control. Conclusions: Within the normal dyeing time for henna hair dye (three hours for natural henna hair dyes and 30 minutes for chemical henna hair dyes) lawsone skin penetration was not observed even when no protective agent was applied. After that time, however, evidence of skin penetration and retention of lawsone and the protective effect of protective agents were observed.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.45-54
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• 2002

The study was carried out to characterize the pharmacokinetics after intravenous (iv, 20 mg/kg) and oral (p.o. 100 mg/kg) administration as oxytetracycline (OTC) and tiamulin (TIA) mixture in swine and to determine interaction between OTC and TIA against various pig pathogenic bacteria. The antibacterial effects of OTC in combination with TIA in vitro showed synergistic effect against Salmonella typhimurium 1925, Pasteurella multocida Type A, P. multocida Type D, Krebsiella Pneumoniae 2001, K. Pneumoniae 1560, K. Pneumoniae 2208, Haemophillus pleuropneumonia S 2, and H. pleuropneumonia S 5, but against additive effect E. coli K88ab and S. choleraesuis on the basis of fractional inhibitory concentration (FIC) index. On the while, after i.v. and p.o. administration of OTC and TIA mixture, each OTC and TIA concentrations in plasma were fitted to an open two-compartment model. After i.v. administration of OTC-TIA mixture, the mean distribution half-life ($T_{1/2{\alpha}}$) of OTC and TIA in plasma showed 0.29 h and 0.17 h, and the mean elimination half-life ($T_{1/2{\beta}}$) of those was 4.36 h and 6.64 h, respectively. The mean volume of distribution at steady state ($Vd_{ss}$) of OTC and TIA was $0.85{\ell}/kg$ and $2.44{\ell}/kg$, respectively. After oral administration of OTC and TIA mixture, the mean maximal absorption concentrations ($C_{max}$) of OTC and TIA were $0.60{\mu}g/m{\ell}$ at 1.07 h ($T_{max}$) and $1.68{\mu}g/m{\ell}$ at 1.85 h ($T_{max}$), respectively. The mean elimination half-life ($T_{1/2{\beta}}$) of those showed 6.84 h and 6.36 h. In conclusion, we could suggest in this study that the combination of OTC and TIA may be recommended for the antibacterial therapy against polymicrobial infections, and both OTC and TIA showed large distribution to tissues and high $C_{max}$ after p.o. administration.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.365-370
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• 2000

This study represents effect to attain to the exhaust gas and the exhaust noise by the inner shapes of automobile muffler, and obtained optimization-data for the inner muffler shapes by the temperature variation of the exhaust gas in muffler. The results of noise show to decrease in order of model-1, 2 and 3 under that the engine speed is 3500 R.P.M and similar values beyond it. CO represented good the model-2 at low engine speed and model-1 at high engine speed. The model-3 was show to tiny variation difference by the variables. HC decrease mostly by increase of the engine speed and expressed low values the model-2 at 3,000 R.P.M and the model-1 at high speed. Wholly, the model-2 expressed stable results. The temperature distributions expressed high distributions by increase of the engine speed, and the model-3 was express most good among three models.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.184-188
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• 2001

In this paper, a new fully digital control method for single-phase UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. The inner current control loop is designed and implemented in the form of internal model control and takes the presence of computational time-delay into account. Therefore, this method provides an overshoot-free reference-to-output response. In the proposed scheme, the outer voltage control loop employing P controller with resonance model implemented by a DSP is introduced. The proposed resonance model has an infinite gain at resonant frequency, and it exhibits a function similar to an integrator for AC component. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been demonstrated by the simulation and experimental results respectively.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.210-216
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• 1990

This study was performed to obtain fundamental data on temperature increases in the dental tissues irradiated by IO.opm laser radiation. For this purpose a experimental facility was established. which was composed of a CO2 laser. a shutter unit and a temperature sensing device. The temperature changes in the pulp chamber of extracted molars. during and after the laser irradiation. were measured as function of laser power. the time of irradration and the thickness of the sample. An empirical formula for the maximum temperature increases, $\DeltaT_m$ was derived from the measured data as follows; $\DeltaT_m=\alphaP\Delta\tauexp(-\betad)$$ where P. $\Delta\tau$ and d are the laser power(W). irradiation time{sec) and the thickness(mm) between pulp chamber and occlusal surface. respectively. Also a theoretical calculation model based on simplified assumptions were established and the results from the calculation were compared with the measured temperature data. A fairly good agreement was obtained.obtained.