• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1540-1541
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• 2006

For limitation and interruption of short circuit currents from low voltage to extra high voltage applications, the electrical equipment including fuses and circuit breakers, are widely used today. But in order to anticipate increasing needs for effective and competitive device for limiting the growing fault current in electrical power systems, fault current limitation technologies and fault current limitation devices are widely introduced and investigated in these days. Fault current limiters are emerging electric equipment which is under development using various methods including superconducting fault current limiter, solid state fault current limiter, arc driving fault current limiters. And these various methods have some advantages and disadvantages to take into considerations In order to commercialize fault current limiters in the electrical networks, a lot of discussions should be given on the point that fault current limiting methods, need for fault current limiters, coordination with existing protective system, and field experience before commercialization. In this paper, recent trends of fault current limiting technologies will be reviewed and the key issues of superconducting fault current limiters will be dealt with. And finally, future applications of superconducting fault current limiters would be discussed.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.11
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• pp.1767-1778
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• 2010

This study investigates applying $TiO_2$ (titanium dioxide) nanoparticles to polypropylene nonwoven fabrics via electrospinning for the development of UV-protective materials. To fabricate uniform nanocomposite fibers, three types of $TiO_2$ nanoparticles were applied: powder, colloid, and $TiO_2$ coated polymer pellets. $TiO_2$/polyurethane (PU) and $TiO_2$/poly(vinyl alcohol) (PVA) nanocomposite fibers were electrospun and the morphology was examined using a field-emission scanning electron microscope and a transmission electron microscope. Layered fabric systems with electrospun $TiO_2$ nanocomposite fiber webs were developed at various concentrations of $TiO_2$ in a range of the web area density. The effects of $TiO_2$ concentration and web area density on UV-protective properties were examined. When $TiO_2$ colloid was added into a PVA polymer solution, uniform nanocomposite fiber webs in which $TiO_2$ particles were evenly dispersed were produced. Water-soluble PVA nanofiber webs were given a heat treatment to stabilize the electrospun PVA fibrous structure against dissolution in water. $TiO_2$/PVA nanoeomposite fiber webs with 2wt% $TiO_2$ and 3.0g/$m^2$ web area density exhibited an ultraviolet protection factor of greater than 50, indicating excellent UV protection.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.2
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• pp.37-43
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• 2007

Adenosine has been reported to provide cytoprotection in the central nervous systems as well as myocardium by activating cell surface adenosine receptors. However, the exact target and mechanism of its action still remain controversial. The present study was performed to examine whether adenosine has a protective effect against $A{\beta}$-induced injury in neuroglial cells. The astrocyte-derived human neuroglioma cell line, A172 cells, and $A{\beta}_{25{\sim}35}$ were employed to produce an experimental $A{\beta}$-induced glial cell injury model. Adenosine significantly prevented $A{\beta}$-induced apoptotic cell death. Studies using various nucleotide receptor agonists and antagonists suggested that the protection was mediated by $A_1$ receptors. Adenosine attenuated $A{\beta}$-induced impairment in mitochondrial functional integrity as estimated by cellular ATP level and MTT reduction ability. In addition, adenosine prevented $A{\beta}$-induced mitochondrial permeability transition, release of cytochrome c into cytosol and subsequent activation of caspase-9. The protective effect of adenosine disappeared when cells were pretreated with 5-hydroxydecanoate, a selective blocker of the mitochondrial ATP-sensitive $K^+$ channel. In conclusion, therefore we suggest that adenosine exerts protective effect against $A{\beta}$-induced cell death of A172 cells, and that the underlying mechanism of the protection may be attributed to preservation of mitochonarial functional integrity through opening of the mitochondrial ATP-sensitive $K^+$ channels.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1539-1548
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• 2017

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that commonly causes fatal infections in cystic fibrosis and burn patients as well as in patients who are hospitalized or have impaired immune systems. P. aeruginosa infections are difficult to treat owing to the high resistance of the pathogen to conventional antibiotics. Despite several efforts, no effective prophylactic vaccines against P. aeruginosa are currently available. In this study, we investigated the activity of the CIA06 adjuvant system, which is composed of alum and de-O-acylated lipooligosaccharide, on a P. aeruginosa outer membrane protein (OMP) antigen vaccine in mice. The results indicated that CIA06 significantly increased the antigen-specific IgG titers and opsonophagocytic activity of immune sera against P. aeruginosa. In addition, the antibodies induced by the CIA06-adjuvanted vaccine exhibited higher cross-reactivity with heterologous P. aeruginosa strains. Finally, mice immunized with the CIA06-adjuvanted vaccine were effectively protected from lethal P. aeruginosa challenge. Based on these data, we suggest that the CIA06 adjuvant system might be used to promote the immunogenicity and protective efficacy of the P. aeruginosa OMP vaccine.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.505-513
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• 2014

The purpose of this study is to evaluate the corrosion protective properties of a Zn-Sn metal spray method according to the contents of Zn and Sn by a CASS test and the electrochemical theory. In the experiment, the CASS test and the electrochemical test were conducted to investigate the corrosion protective property of the Zn-Sn Metal Spray system, the Zinc galvanizing system, and the heavy duty coating system. As a result, it was confirmed that the Zn-Sn (65:35) Metal Spray system had very high corrosion protective property through the electrochemical characteristic as comparison with the other anti-corrosion systems and was very effective to prevent steel products from corrosion.

• Journal of Environmental Science International
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• v.20 no.12
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• pp.1509-1519
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• 2011

The protective effect of nitric oxide (NO) on the antioxidant system under paraquat(PQ) stress was investigated in leaves of 8-week-old lettuce (Lactuca sativa L.) plants. PQ stress caused a decrease of leaf growth including leaf length, width and weight. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated PQ stress induced growth suppression. SNP permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under PQ exposure, suggesting that NO has protective effect on chloroplast membrane in lettuce leaves. Flavonoids and anthocyanin were significantly accumulated in the leaves upon PQ exposure. However, the rapid increase of these compounds was alleviated in the SNP treated leaves. PQ treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in the leaves, while SNP prevented PQ induced increase in malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that SNP serves as an antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, superoxide dismutase (SOD) and catalase (CAT) in lettuce leaves in the presence of NO donor under PQ stress were higher than those under PQ stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, to the lettuce leaves arrested SNP mediated protective effect on leaf growth, photosynthetic pigment and antioxidant systems. However, PTIO had little effect on lettuce leaves under PQ stress compared with that of PQ stress alone. The obtained data suggest that the damage caused by PQ stress is in part due to increased generation of active oxygen by maintaining increased antioxidant enzyme activities and SNP protects plants from oxidative stress. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative damage induced by PQ stress and thus confer PQ tolerance.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.94-99
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• 2006

This study investigated the protective effect of the butanol (BuOH) fraction from Laminaria japonica (BFLJ) extract on high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). Freeze-dried L japonica was extracted with distilled water, and the extracted solution was mixed with ethanol then centrifuged. The supernatant was subjected to sequential fractionation with various solvents. The BuOH fraction was used in this study because it possessed the strongest antioxidant activity among the various solvent fractions. To determine the protective effect of the BFLJ, oxidative stress was induced by exposing of HUVECs to the high glucose (30 mM) or normal glucose (5.5 mM) for 48 hr. Cell viability, lipid peroxidation, glutathione (GSH) concentration, and antioxidant enzyme activities such as catalase, superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and glutathion reductase (GSH-re) were measured. Exposure of HUVECs to high glucose for 48 hr resulted in a significant (p<0.05) decrease in cell viability, SOD, GSH-px and GSH-re and a significant (p<0.05) increase in thiobarbituric acid reactive substances (TBARS) formation in comparison to the cells treated with 5.5 mM glucose or untreated with glucose. BFLJ treatment decreased TBARS formation and increased cell viability, GSH concentration, and activities of antioxidant enzymes including catalase, SOD, GSH-px, and GSH-re in high glucose pretreated HUVECs. These results suggest that BFLJ may be able to protect HUVECs from high glucose-induced oxidative stress, partially through the antioxidative defence systems.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.147-155
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• 1999

Antioxidant effects of serotonin and L-DOPA on neuronal tissues were examined by studying the oxidative damages of brain synaptosomal components. The study further explored the mechanism by which they exert protective actions. Serotonin and L-DOPA (1 ${\mu}M$ to 1 mM) significantly inhibited lipid peroxidation of brain tissues by either $Fe^{2+}$ and ascorbate or t-butyl hydroperoxide in a dose dependent fashion. Protective effect of serotonin on the peroxidative actions of both systems was greater than that of L-DOPA. Protein oxidation of synaptosomes caused by $Fe^{2+}$ and ascorbate was attenuated by serotonin and L-DOPA. Protein oxidation more sensitively responded to L-DOPA rather than serotonin. Serotonin and L-DOPA (100 ${\mu}M$) decreased effectively the oxidation of synaptosomal sulfhydryl groups caused by $Fe^{2+}$ and ascorbate. The production of hydroxyl radical caused by either $Fe^{3+},$ EDTA, H_2O_2$ and ascorbate or xanthine and xanthine oxidase was significantly decreased by serotonin and L-DOPA (1 mM). Equal concentrations of serotonin and L-DOPA restored synaptosomal $Ca^{2+}$ uptake decreased by $Fe^{2+}$ and ascorbate, which is responsible for SOD and catalase. Protective effects of serotonin and L-DOPA on brain synaptosomes may be attributed to their removing action on reactive oxidants, hydroxyl radicals and probably iron-oxygen complex, without chelating action on iron.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.3
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• pp.416-425
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• 2010

The object of this study was to observe the protective effects of Yijin-tang-gamibang (YJGMB), Yijin-tang has been traditionally used in the Korean Medicine for treating various digestive diseases. The study showed that it is effective on reflux esophagitis induced by pylorus and forestomach ligation in rats. Three different dosages of YJGMB extracts, 200, 100 and 50 mg/kg, were orally pretreated, once a day for 28 days before pylorus and forestomach ligation. Seven groups, each of 8 rats per group were used in the present study. The results were compared with omeprazole, antioxidant and proton pump inhibitor, 30 and 10 mg/kg treated group. YJGMB 200 mg/kg were showed similar protective effects as compared with 30 mg/kg of omeprazole but more favorable effects were observed in 200, 100 and 50 mg/kg of all YJGMB treated rats as compared with omeprazole 10 mg/kg in the present study. In addition, YJGMB 200 mg/kg were showed more favorable antioxidant effects as compared with 30 mg/kg of omeprazole in the present study. Detail mechanism studies should be conduced in future with the screening of the biological active chemical compounds in herbs.

• International Journal of Human Ecology
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• v.12 no.2
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• pp.13-24
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• 2011

This study compared actual weight with perceived weight, described the prevalence of unhealthy weight control behavior, determined the differences in psychological and personal variables between participants that reported unhealthy weight control behavior and those who did not, and examined the relationship of eating habits to unhealthy weight control behavior for Korean adolescents. The study population consisted of a nationally representative sample of middle and high school students who completed the Fifth Korea Youth Risk Behavior Web-based Survey (KYRBWS): Fifth in 2009. Among the 75,066 participants of KYRBWS, 35,473 (n = 18,851 girls and 16,622 boys) were eligible for a research focused on unhealthy weight control behavior. The results of this research were as follows: First, there were considerable discrepancies (45.1% of girls and 32.8% of boys) between the perceived weight and the actual weight. Second, overall, unhealthy weight control behavior was more prevalent in girls and fasting was the most commonly reported behavior. Third, participants that reported unhealthy weight control behavior scored significantly lower on scaled measures of happiness, health, academic achievement, and economic status; in addition, they scored higher on stress measures. Fourth, girls and boys shared common protective factors of having breakfast and vegetables more often, perceiving their weight as underweight rather than overweight, and having a correct weight conception. Protective factors unique to girls were having lunch and dinner more often. Girls and boys shared common risk factors of the consumption of soda, fast food, instant noodles, and snacks more often, while consumption of fruit more often was a risk factor only for girls. The improvement of protective factors and minimization of risk factors through Home Economics classes (and other classes relevant to health) may mitigate unhealthy weight control behavior of adolescents.