• Journal of Korea Water Resources Association
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• v.38 no.1
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• pp.59-71
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• 2005

Mountain watersheds are a lot of problems about soil erosion because of frequent wildfire occurrence. Runoff and soil erosion caused by the rain on a hillslope after wildfire are dependent on cover factor. And these has been a decrease by the cover factor recovery following time passage. The present paper defines the dynamic sensitivity of runoff and soil erosion that is the rate of runoff volume and soil erosion weight to rainfall energy and analyzes characteristics of the sensitivity for variation of cover factor, In according to the correlation analysis between other parameters and sensitivities, the sensitivity is the most dependent on the cover factor and the relation is exponential. The sensitivities after wildfire have suitable relation with treatment method for the mitigation of burnt forest and wildfire intensity. It was confirmed that the variation of soil erosion sensitivities come upon the range of stability in 5 years after wildfire.

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.443-450
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• 2005

In the present study, we have characterized the choline transport system and examined the influence of various amine drugs on the choline transporter using a conditionally immortalized rat brain capillary endothelial cell line (TR-BBB) in vitro. The cell-to-medium (C/M) ratio of $[^3{H}]choline$ in TR-BBB cells increased time-dependently. The initial uptake rate of $[^3{H}]choline$ was concentration-dependent with a Michaelis-Menten value, $K_{m}$, of $26.2\pm2.7{\mu}M$. The $[^3{H}]choline$ uptake into TR-BBB was $Na^{+}-independent$, but was membrane potential-dependent. The $[^3{H}]choline$ uptake was susceptible to inhibition by hemicholinium-3, and tetraethy-lammonium (TEA), which are organic cation transporter substrates. Also, the uptake of $[^3{H}]choline$ was competitively inhibited with $K_{i}$ values of $274 {\mu}M, 251 {\mu}M and 180 {\mu}M$ in the presence of donepezil hydrochloride, tacrine and $\alpha-phenyl-n-tert-butyl nitrone$ (PBN), respectively. These characteristics of choline transport are consistent with those of the organic cation transporter (OCT). OCT2 mRNA was expressed in TR-BBB cells, while the expression of OCT3 or choline transporter (CHT) was not detected. Accordingly, these results suggest that OCT2 is a candidate for choline transport at the BBB and may influence the BBB permeability of amine drugs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.33-40
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• 1998

The composite SiO$_2$/Si$_3$N$_4$/SiO$_2$(ONO) film formed by oxidation on nitride film has been widely studied as DRAM stacked capacitor multi-dielectric films. Load lock(L/L) LPCVD system by HF cleaning is used to improve electrical capacitance and to scale down of effective thickness for memory device, but is brings a new problem. Nitride film deposited using HF cleaning shows selective deposition on poly silicon and oxide regions of capacitor. This problem is avoidable by carpeting chemical oxide using $H_2O$$_2$cleaning before nitride deposition. In this paper, we study the limit of nitride thickness for abnormal oxidation and the initial deposition time for nitride deposition dependent on underlayer materials. We proposed an advanced fabrication process for stacked capacitor in order to avoid selective deposition problem and show the usefulness of nitride deposition using L/L LPCVD system by $H_2O$$_2$cleaning. The natural oxide thickness on polysilicon monitor after HF and $H_2O$$_2$cleaning are measured 3~4$\AA$, respectively. Two substrate materials have the different initial nitride deposition times. The initial deposition time for polysilicon is nearly zero, but initial deposition time for oxide is about 60seconds. However the deposition rate is constant after initial deposition time. The limit of nitride thickness for abnormal oxidation under the HF and $H_2O$$_2$cleaning method are 60$\AA$, 48$\AA$, respectively. The results obtained in this study are useful for developing ultra thin nitride fabrication of ONO scaling and for avoiding abnormal oxidation in stacked capacitor application.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.946-954
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• 2007

The purpose of this research was to investigate the anti-inflammatory effects of Yongdamsagantanghaphwangryunhaedogkagam(YSHHK) which has been medicated the patient such as breast cellulitis. YSHHK did not show any cytotoxic effect on mouse lung fibroblast cells at any of the concentrations evaluated(200, 100, 50, 10, 1 ${\mu}g/m{\ell}$). YSHHK in RAW264.7 cell inhibited $IL-1{\beta}$, IL-6, $TNF-{\alpha}$, COX-2 and NOS-II mRNA genes expression in a concentration-dependent manner. YSHHK inhibited NO production significantly at the concentration of 100, 50 ${\mu}g/m{\ell}$ and ROS production in a concentration-dependent manner. YSHHK inhibited $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ production significantly in serum of mice with LPS-induced acute inflammation. YSHHK increased survival rate of mice with LPS-induced lethal endotoxemia, compared to the control group, from the 3rd day onward. These results suggest that Yongdamsagantanghaphwangryunhaedogkagam(YSHHK) can be useful in treating mammary diseases caused by inflammation such as breast cellulitis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.860-868
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• 2007

The purpose of this research was to investigate the anti-inflammatory effects of Kamibokwontonggi-san(KBTS) which has been medicated the patient such as mastitis, mammary tuberculosis. KBTS in RAW264.7 cell inhibited IL-1 ${\beta}$, IL-6, TNF-${\alpha}$, COX-2 and NOS-II mRNA genes expression in a concentration-dependent manner. KBTS inhibited NO production significantly at 100, 50 ${\mu}g/m{\ell}$ and ROS production in a concentration-dependent manner. KBTS inhibited IL-1${\beta}$, IL-6 and TNF-${\alpha}$ production significantly in serum of acute anti-inflammation-induced mice and the survival rate at the 3rd day on LPS-induced lethal endotoxemia. These results suggest that Kamibokwonntonggi-san (KBTS) can be useful in treating a lot of women diseases caused by inflammation such as mastitis, mammary tuberculosis, pelvic inflammatory disease and pelvic tuberculosis.

• Environmental Analysis Health and Toxicology
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• v.25 no.3
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• pp.241-251
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• 2010

Crucian carp (Carassius auratus) has been used as the sentinel species for POPs (Persistent Organic Pollutants) monitoring in aquatic environment. However, there is little information for dioxin toxicity and especially, early life stage toxicity in crucian carp have been never carried out. In this study, we investigated several toxic effects for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in fertilized egg obtained by natural fertilization from crucian carp. The embryos at 3 h post-fertilization (hpf) were treated with 0.039, 0.156, 0.625, and 2.5 (${\mu}g/L$) TCDD by waterborne exposure for 60 minutes and changed with fresh water 2 times per day. Fertilized eggs started hatching at 51 hpf and TCDD exposed embryo showed decrease of hatching rate in a dose-dependent manner at 75 hpf. Pericardial edema was continuously observed in larvae exposed to TCDD from hatching start time (51 hpf), followed by the onset of mortality. In addition, AhR-related gene, CYP1A was clearly increased by TCDD in a dose dependent manner. These results indicated that fertilized eggs obtained from crucian carp have the TCDD related gene regulation and a distinct TCDD developmental toxicity syndrome by TCDD exposure. Therefore, we suggested that early life stage test in crucian carp could be used as test methods on dioxins toxicity.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.349-354
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• 2006

The aromatic hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the biological and toxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related chemicals. The application of recombinant reporter plasmid such as the firefly luciferase gene has proven to be a very effective method to detect these chemicals. The bioassay system, CALUX, is sensitive in directly detecting AhR-agonists from a variety of environmental and biologic materials. However, responses of the AhR-dependent bioassays are dependent on the cell types used. Thus, we developed a sensitive bioassay using the recombinant mouse hepatoma cell (Hepa1c1c7) for the determination of dioxins. The recombinant cell line was stably transfected with firefly luciferase reporter gene (pGudLuc1.1). The transfected cells showed the highest induction of luciferase activity at 4.5 hr and a decrease beyond this time point. The system showed the highest sensitivity of detection ever reported. Upon TCDD exposure cells showed 2 fold increase at 10 pM and 7 fold increase at 100 pM, respectively. The passage number after the transfection played an important role in the sensitivity. The increase of passage number tended to increase the sensitivity of the cells up to 15. The media without phenol red showed a higher induction rate than with phenol red, suggesting the preferable use of phenol red-free media for the bioassay. Since each of the assays has unique characteristics that make them suitable for some screening applications and not others, development of sensitive bioanalytical methods based on a variety of cellular systems in a key to the successful determination of dioxins. The bioassay system developed in this study will contribute to further development of successful screening the AhR agonists among the environmental mixture. In addition, the rapid and sensitive nature of this cellular system can be applied as a valuable tool to screen the dioxin-like moieties among the prodrugs at the initial stage, thereby expediting the new drug discovery.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.63-72
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• 2000

Chronic exposure to cadmium (Cd) results in an inhibition of protein endocytosis in the renal proximal tubule, leading to proteinuria. In order to gain insight into the mechanism by which Cd impairs the protein endocytosis, we investigated the effect of Cd on the acidification of renal cortical endocytotic vesicles (endosomes). The endosomal acidification was assessed by measuring the pH gradient-dependent fluorescence change, using acridine orange or FITC-dextran as a probe. In renal endosomes isolated from Cd-intoxicated rats, the $V_{max}$ of ATP-driven fluorescence quenching ($H^+-ATPase$ dependent intravesicular acidification) was significantly attenuated with no substantial changes in the apparent $K_m,$ indicating that the capacity of acidification was reduced. When endosomes from normal animals were directly exposed to free Cd in vitro, the $V_{max}$ was slightly reduced, whereas the $K_m$ was markedly increased, implying that the biochemical property of the $H^+-ATPase$ was altered by Cd. In endosomes exposed to free Cd in vitro, the rate of dissipation of the transmembrane pH gradient after $H^+-ATPase$ inhibition appeared to be significantly faster compared to that in normal endosomes, indicating that the $H^+-conductance$ of the membrane was increased by Cd. These results suggest that in long-term Cd-exposed animals, free Cd ions liberated in the proximal tubular cytoplasm by lysosomal degradation of cadmium-metallothionein complex (CdMT) may impair endosomal acidification 1) by reducing the $H^+-ATPase$ density in the endosomal membrane, 2) by suppressing the intrinsic $H^+-ATPase$ activity, and 3) possibly by increasing the membrane conductance to $H^+$ ion. Such effects of Cd could be responsible for the alterations of proximal tubular endocytotic activities, protein reabsorption and various transporter distributions observed in Cd-exposed cells and animals.

• Journal of Astronomy and Space Sciences
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• v.4 no.1
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• pp.11-23
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• 1987

In dward nova we assume the primary star as a white dwarf and the secondary as the late type star which filled Roche lobe. Mass flow from the secondary star leads to the formation of thin accretion disk around the white dwarf. We use the $\alpha$ parameter as viscosity to maintain the disk form and propose that the outburst in dwarf nova cause the step increase of source term. With these assumptions we solve the basic equations of stellar structure using New-Raphson method. We show the physical parameters like temperature, density, pressure, opacity, surface density, height and flux to the radius of disk. Changing the value of $\alpha$, we compare several parameters when mass flow rate is constant with those of when luminosity of disk is brightest. At the same time, we obtain time-dependent variations of luminosity and mass of disk. We propose the suitable range of $\alpha$is 0.15-0.18 to the difference of luminosity. We compare several parameters of disk with those of the normal late type stars which have the same molecular weight of disk. These show the temperature and pressure of disk are similar to those of normal stars but the density of disk is lower. Maybe the outburst in dwarf nova is due to the variation of the $\alpha$ value instead of increment of mass flow from the secondary star.

• Journal of Surface Science and Engineering
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• v.36 no.4
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• pp.296-300
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• 2003

Extended cylindrical magnetron sputtering system with rotating 600-mm long and 90-mm diameter graphite cathode and pulsed power supply voltage generator were developed and fabricated. Time-dependent Langmuir probe characteristics as well as carbon films thickness were measured. It was shown that ratio of ions flux to carbon atoms flux for pulsed magnetron discharge mode was equal to $\Phi_{i}$ $\Phi$sub C/ = 0.2. It did not depend on the discharge current in the range of $I_{d}$ / = 10∼60 A since both the plasma density and the film deposition rate were found approximately proportional to the discharge current. In spite of this fact carbon film structure was found to be strongly dependent on the discharge current. Grain size increased from 100 nm at $I_{d}$ = 10∼20 A to 500 nm at $I_{d}$ = 40∼60 A. To deposit fine-grained hard nanocrystalline or amorphous carbon coating current regime with $I_{d}$ = 20 A was chosen. Pulsed negative bias voltage ($\tau$= 40 ${\mu}\textrm{s}$, $U_{b}$ = 0∼10 ㎸) synchronized with magnetron discharge pulses was applied to a substrate and voltage of $U_{b}$ = 3.4 ㎸ was shown to be optimum for a hard carbon film deposition. Lower voltages were not sufficient for amorphization of a growing graphite film, while higher voltages led to excessive ion bombardment and effects of recrystalization and graphitization.