• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.453-457
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• 2007

Zinc oxide (ZnO) and Ga doped zinc oxide (GZO) with different thickness in range of 10nm to 100nm are prepared on glass substrate by RF magnetron sputtering at room temperature. The structural and optical properties of the thin films is evaluated. The structural properties of ZnO and GZO are investigated by Tunneling Electron Microscopy (TEM) and scanning electron microscopy (SEM). Optical properties are also investigated by UV-VIS-NIR spectrophotometer (200$\sim$1400nm). The much larger grain size of ZnO compared to GZO decreased the light scattering at the grain boundary and improved the transmittance. The transmittance of ZnO is higher than that of GZO through all of the ranges of wavelengths. In case of over 50nm, we found that the transmittance of ZnO is 20% higher than that of GZO.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.67-76
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• 1990

Hydrocortisone 50 mg/kg (HC), dehydroepiandrosterone 250 mg/kg (DHEA), ${\beta}-estradiol$ 5 mg/kg (E2), and testosterone 20 mg/kg (TS) were subcutaneously injected into the castrated ICR mice at noon for four days, and the animals were sacrificed at 10-12 A.M. of the fifth day. The intestinal DAO activity was significantly decreased by HC, but it was rather increased by E2 and TS, respectively. And DHEA did not change the DAO activity. But the hepatic MAO activity was not affected by anyone of HC, DHEA, E2, and TS. Aminoguanidine 25 mg/kg produced the marked decrease of the intestinal DAO activity and the significant increases of the intestinal PT and SD contents, but it did not change the hepatic polyamine contents. HC and DHEA induced the significant increase of the intestinal PT content. E2 induced the marked increase of the hepatic PT content and the moderate increase of the intestinal PT content. TS little affected the polyamine contents of the liver and intestine. These results suggest that the E2-induced increase of the hepatic PT content is rather ascribed to the greater enhancement of PT synthesis than the inhibition of polyamine catabolism, and that the HC-induced increase of the intestinal PT content is due partly to the inhibition of polyamine catabolism via DAO.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.166-170
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• 2011

Modem people have begun to have the nationwide interest in the rice wine called Makgeolri which is one of the traditional Korean alcoholic liquors. This study was performed to investigate the effects of San sung Makgeolri extract (SM) on antioxidation together with the determination of pH and dissolved oxygen (DO) in the progress of fermentation in the lipopolysaccharide(LPS)-treated rats. We examined the levels of SOD (superoxide dismutase), CAT (catalase), GPx (glutathione peroxidase) in liver homogenates and the histopathological observations in liver tissue. LPS-treated group markedly decreased the levels of SOD, CAT and GPx. But SM + LPS-treated group significantly increased the levels of them. Furthermore, the antioxidative effects of SM were supported by the histopathological observations in liver tissue which showed severe inflammation and necrosis in LPS-treated group, compared to the attenuated inflammation and necrosis in SM + LPS-treated group. This results suggested that SM could be a candidate of antioxidative material in spite of alcoholic liquors.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.23-27
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• 2008

We have investigated the effect of annealing on the structural and optical properties of polycrystalline Ga doped ZnO (GZO) films grown on glass substrates by RF-magnetron sputter at room temperature. The structural and optical properties of as-grown GZO films were characterized and then samples were annealed at $400{\sim}600^{\circ}C$ in $N_2$ ambient for 30, 60 minutes, respectively. The field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were used to measure the grain size and the crystalline quality of the films. We found that the crystalline quality was improved and the grain size tends to be increased. The optical properties of GZO thin films were analyzed by UV-VIS-NIR spectrophotometers. It is found that optical properties of thin films are increased by annealing and can be used for transparent electrode application. We believe that the appropriate post-growth heat treatment could be contributed to the improvement of GZO-based devices.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.629-636
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• 2011

Objectives : The purpose of this study was to determine the effects of oral health on the quality of life of elderly patients with dentures or implants. It is our intention that through this analysis we can aid seniors in making the choice between dentures or implants, considering future masticatory function and the likely effects of this decision on the patients quality of life. Methods : This survey was conducted between November 1, 2010 and November 25, 2010, in Kyunggi-Do, whasung city. The research was carried out at one public health center, among elderly patients. 105 seniors were surveyed using the direct interviewing method, oral health related quality of life was measured by the Philadelphia Geriatric Center(PGC) Morale Scale. Collected data was examined using the SPSS 13.0 program, using frequency, mean, and standard deviation analysis, T-test and $x^2$ test. Results : The number of residual teeth for patients who have implants was $20.45{\pm}5.85$, while among those patients with dentures the number was considerably lower, $8.11{\pm}7.66$(p<0.05). The results of patients masticatory function, was $28.13{\pm}2.40$ for those with implants, and $25.35{\pm}4.15$ with dentures. The results were better for those with implants. Among implant patients overall satisfaction was rated $25.21{\pm}3.63$, higher than for those with dentures $20.20{\pm}6.79$(p<0.05). Quality of life was scored higher for patients with implants($12.76{\pm}2.61$) compared to those with dentures($10.47{\pm}3.52$)(p<0.05). The subjects masticatory function was highly related to the number of remaining teeth and greater masticatory function had a positive effect on patients quality of life and life satisfaction. Conclusion : Dental treatments such as dentures and implants will have a great influence on patients quality of life and life satisfaction. Implants can improve the oral health related quality of life and satisfaction and the general quality of life more than denture therapy.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.127-135
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• 1999

As part of a study on the effects of dexamethasone and dehydroepiandrosterone (DHEA) on the biological roles of astrocytes in brain injury, this study evaluated the effects of dexamethasone and DHEA on the responses of primary cultured rat cortical astrocytes to lipopolysaccharide (LPS) and antimycin A. Dexamethasone decreased spontaneous release of LDH from astrocytes, and the dexamethasone effect was inhibited by DHEA. However, the inhibitory effect of DHEA on the dexamethasone-induced decrease of LDH release was not shown in astrocytes treated with LPS, and antimycin A-induced LDH release was not affected by dexamethasone or DHEA. Unlike dexamethasone, DHEA increased MTT value of astrocytes and also attenuated the antimycin A-induced decrease of MTT value. Glutamine synthetase activity of astrocytes was not affected by DHEA or LPS but increased by dexamethasone, and the dexamethasone- dependent increase was attenuated by DHEA. However, antimycin A markedly decreased glutamine synthetase activity, and the antimycin A effect was not affected by dexamethasone or DHEA. Basal release of $[^3H]arachidonic$ acid from astrocytes was moderately increased by LPS and markedly by antimycin A. Dexamethasone inhibited the basal and LPS-dependent releases of $[^3H]arachidonic$ acid, but neither dexamethasone nor DHEA affected antimycin A-induced $[^3H]arachidonic$ acid release. Basal IL-6 release from astrocytes was not affected by dexamethasone or DHEA but markedly increased by LPS and antimycin A. LPS-induced IL-6 release was attenuated by dexamethasone but was little affected by DHEA, and antimycin A-induced IL-6 release was attenuated by DHEA as well as dexamethasone. At the concentration of dexamethasone and DHEA which does not affect basal NO release from astrocytes, they moderately inhibited LPS-induced NO release but little affected antimycin A-induced decrease of NO release. Taken together, these results suggest that dexamethasone and DHEA, in somewhat different manners, modulate the astrocyte reactivity in brain injuries inhibitorily.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.137-146
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• 1999

Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. $[^3H]Glutamate$ uptake: LPS and antimycin A decreased $V_{max},$ but both drugs had little effect on $K_m.$ Dexamethasone also decreased basal $V_{max}$ without any significant effect on $K_m.$ And dexamethasone further decreased the antimycin A-induced decrease of $V_{max}.$ DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. $[^{14}C]Putrescine$ uptake: LPS increased $V_{max},$ and antimycin A decreased $V_{max}.$ They showed little effect on $K_m.$ Dexamethasone decreased $V_{max}$ of basal uptake and further decreased the antimycin A-induced decrease of $V_{max},$ and also decreased $V_{max}$ to less than control in LPS-treated astrocytes. DHEA did not affect $K_m$ and the change of $V_{max}$ by LPS or antimycin A. 3. $[^{14}C]Spermine$ uptake: Antimycin A decreased $V_{max},$ and LPS might increase $V_{max}.\;K_m$ was little affected by the drugs. Dexamethasone decreased basal $V_{max}$ and might further decrease the antimycin A-induced decrease of $V_{max}.$ And dexamethasone also decreased $V_{max}$ to less than control in LPS-treated astrocytes. DHEA might increase basal $V_{max}$ and $V_{max}$ of LPS-treated astrocytes. 4. $V_{max}$ of glutamate uptake by astrocytes was increased by putrescine (1000 ${\mu}M$ & 2000 ${\mu}M$) and spermidine (200 ${\mu}M,$ 500 ${\mu}M$ & 2000 ${\mu}M$). Spermine, 200 ${\mu}M$ (and 100 ${\mu}M$), also increased $V_{max},$ but a higher dose of 2000 ${\mu}M$ decreased $V_{max}.\;K_m$ of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease $K_m$ of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.

• The Korean Journal of Pharmacology
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• v.27 no.1
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• pp.81-88
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• 1991

The bilateral castration of male mice was operated under light ether anesthesia, and the sham operated mice were considered as the uncastrated. The treatments of mice with the following steroids were started one hour after operation. Hydrocortisone 50 mg/kg (HC), dehydroepiandrosterone 250 mg/kg (DHEA), ${\beta}-estradiol$ 5 mg/kg (E2), and testosterone 20mg/kg (TS) were subcutaneously injected into male ICR mice at noon for four days. Animals were sacrificed in the next-morning (at 10-12 A.M.) after the last injection. The intestinal putrescine(PT) content was lower and the liver and intestinal spermine(SM) contents were higher in castrated mice(CM), comparing with those of uncastrated mice (UCM). The intestinal PT content of UCM was markedly increased HC. But all brain polyamines of CM were significantly decreased by it. And HC also increased the spermidine(SD) content of kidney and liver and the intestinal PT content in CM. E2 induced the marked increase of liver PT content with the moderate increase of renal SD in UCM. And E2 significantly increased the brain and liver PT contents and the all renal polyamine contents in CM. Both of DHEA and TS induced the increase of renal PT content in UCM, and they also induced the marked increases of all renal polyamines of CM. In addition, TS increased the brain SM of CM. These results suggest that the steroidal regulation mechanism of brain, kidney, liver, and intestine seems to be different from one another, and the renal activity of polyamine synthesis can be markedly enhanced by sex steroids.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.83-91
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• 1996

Activation of $K^+$ channels induces relaxation of smooth muscles by reducing electrical excitability and cytosolic free $Ca^{2+}$ level. ${\beta}$-adrenergic agonist isoproterenol is known to induce relaxation of the uterine smooth muscle by membrane hyperpolarization and $K^+$ efflux. Recently it is suggested that the activity of $Ca^{2+}$-activated $K^+$ channel was increased by isoproterenol in the uterine myocytes isolated from myometrium of the pregnant rat. However, the type of $K^+$ channel mediating the relaxant effect of isopreterenol in the tissue level has not yet studied. In this work, we investigated the type of $K^+$ channels involved in the isoproterenol-induced relaxation of uterine smooth muscle by measuring the integrated insometric tension of the estrogen-treated isolated nonpregnant rat uterus. Contraction of uterine tissue was induced by oxytocin (0.2nM, 2~3 contractions/min) or high KCl(20~80mM). The result are as follows : 1. Isoproterenol($10^{-10}{\sim}10^{-4}M$) inhibited oxytocin-induced contraction of isolated rat uterus($EC_{50}=1.17{\times}10^{-10}M$). 2. Isoproterenol($10^{-10}{\sim}10^{-4}M$) effectively inhibited uterine contraction induced by low KCl(20~40mM) but little those induced by high KCl(60~80mM). 3. Relaxant effect of isoproterenol($10^{-10}{\sim}10^{-4}M$) on 0.2nM oxytocin-induced contraction was effectively reduced by 4-aminopyridine(3, 10mM) but little by TEA(10~30mM), $Ba^{2+}$($1{\sim}30{\mu}M$) and glibenclamide($100{\mu}M$). Our data suggest that the relaxant effect of isoproterenol is mediated by the $K^+$ channel(s) which can be blocked by 4-aminopyridine.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.352-357
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• 2009

The InAs multi-quantum dots (MQDs) solar cell and InGaAs multi-quantum wells (MQWs) solar cell to cover 1.1 eV and 1.3 eV were designed by 1D poisson, respectively. The MQDs and MQWs of 5, 10, 15 layers were grown by molecular beam epitaxy. The photo luminescence results showed that the 5 period stacked MQDs have the highest intensity at around 1.1 eV with 57.6 meV full width at half maximum (FWHM). Also we can observe 10 period stacked MQWs peak position which has highest intensity at 1.31 eV with 12.37 meV FWHM. The density and size of QDs were observed by reflection high energy electron diffraction pattern and atomic force microscope. Futhermore, AlGaAs/GaAs sandwiched tunnel junctions were modified according to the width of GaAs layer on p-type GaAs substrates. The structures with GaAs width of 30 nm and 50 nm have backward diode characteristics. In contrast, tunnel diode characteristics were observed in the 20 nm of that of sample.