• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.339-344
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• 2010

Oxygen depleted water mass can damage aquatic animals not only in direct way but also in indirect way by generating toxic substances including occurrence of hydrogen sulfide and ammonia which are also highly detrimental to animal life in the water mass. An oxygen dissolution device was developed, which makes turnover of the oxygen rich (over 20 mg/L) surface water down to the bottom where hypoxia is evident and tested the device in terms of oxygen recovery in the oxygen depleted bottom water. the device with turnover rates of $3.6\;m^2$/min at the liquid oxygen injection rate of 48~26.3 L/min could recover dissolved oxygen level to 7~25 mg/L at depth 7 m to lead to the dissolution level of over 90% by the supply of liquid oxygen. The running advantage of the device is that it does not require any auxiliary tank and higher energy for operation. Therefore, it can be highly useful device to relieve damages to the farmed animals in the oxygen depleted waters.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.17-21
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• 2011

Korean bennudagrass collections showed diverse genetic variations in their morphology, growth habit, and cytological aspects. Chromosome number and nuclear DNA content of the bennudagrasses indicated a ploidy level ranging from triploid (2n=3x) to hexaploid (2n=6x). In this study, we investigated the different responses of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase) and cell membrane stability of those bennudagrass cytotypes to lower temperature and shorter day length, which meets a dormant induction in Korea. All the antioxidant enzymes were found to be higher during dormant stage, while the heme-containing catalase which converts hydrogen peroxide ($H_2O_2$) to water and oxygen molecules was activated before dormant initiation in the three cytotypes except for hexaploid bennudagrass. The triploid and tetraploid which exhibited relatively finer leaves and a rapid establishment speed were found to show increased activities of superoxide dismutase and peroxidase enzyme. The malondialdehyde(MDA) which is a product of lipid peroxidation in the cell membrane damaged by the hydroxyl radical was increased in all cytotypes as temperature declined, and tri- and tetraploids which had more protective antioxidant enzymes demonstrated a significantly lower MDA production. Similarly electrolyte leakage was higher in penta- and hexaploidy, seemingly more damage to cell membrane when low temperature was implemented. Results indicated that antioxidant responses of different cytotypes were genetically specific, which needs to be investigated the relevance with the low temperature tolerance in the bermudagrass further at the molecular level.

• 보존과학연구
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• s.34
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• pp.20-29
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• 2013

Paper, textile and wood materials are mainly consisted of cellulose. Cellulose is high molecule and make up the strong crystalline structure by hydrogen bonds. In particular, the polymerization degree of cellulose are closely related to the strength of fiber, and the permanence. the useful life of fiber, also depends on the degradation of this substance. The viscosity of cellulose is considered to be an important indicator of fiber damage in high molecule polymers. The viscosity measurements with CED solution is used to measure the molecular weight and the degree of polymerization of cellulose. Cellulose viscosity of wood fibers is measured with TAPPI standard method T230. However, TAPPI standard method T230 is difficult to completely dissolving the cellulose of high molecular weight and large degree of polymerization, such as Korea traditional papers and fabrics made with mulberry, ramie, cotton fibers. In this study, The high viscosity of hanji and fabric was measured with TAPPI standard method T254. T254 method is that the cellulose specimen with the proper amount of weaker (0.167M CED) solution, and completely dissolved with the stronger (1.0M CED) solution. It was found that cellulose with high degree of polymerization was dissolved more easily in general CED method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.1053-1062
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• 2011

Reactive oxygen species (ROS), including singlet oxygen (${O_2}^1$), superoxide anion radical ($O_2{\cdot}^-$), hydroxyl radical ($HO{\cdot}$), peroxyl radical ($ROO{\cdot}$), hydrogen peroxide ($H_2O_2$), and hypochlorous (HOCl), are generated as byproducts of normal cellular metabolism. ROS induce damage to many biological molecules, such as lipids, proteins, carbohydrates, and DNA. It is widely believed that some degenerative diseases caused by ROS can be prevented by the high intake of fruits and vegetables due to their antioxidant activities. Recently, research on natural antioxidants has become increasingly active in various fields. Several assays have been developed to measure the total antioxidant capacity of antioxidants in fruits and vegetables in vitro. These assays include those for DPPH radical scavenging activity, SOD-like activity, total polyphenol content, oxygen radical absorbance capacity, reducing power, trolox equivalent antioxidant capacity (ABTS assay), single-cell gel electrophoresis (comet assay), and a cellular antioxidant activity assay. Because different antioxidant compounds may act through different mechanisms in vitro, no single assay can fully evaluate the total antioxidant capacity of foods. Due to the complexity of the composition of foods, it is important to be able to measure antioxidant activity using biologically relevant assays. In this review, recently used assays were selected for extended discussion, including a comparison of the advantages and disadvantages of each assay and their application to fruits and vegetables.

• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.1
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• pp.21-28
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• 2017

Background: The skin consists of tightly connected keratinocytes, and prevents extensive water loss while simultaneously protecting against the entry of microbial pathogens. Excessive cellular levels of reactive oxygen species can induce cell apoptosis and also damage skin integrity. Propofol (2,6-diisopropylphenol) has antioxidant properties. In this study, we investigated how propofol influences intracellular autophagy and apoptotic cell death induced by oxidative stress in human keratinocytes. Method: The following groups were used for experimentation: control, cells were incubated under normoxia (5% $CO_2$, 21% $O_2$, and 74% $N_2$) without propofol; hydrogen peroxide ($H_2O_2$), cells were exposed to $H_2O_2$ ($300{\mu}M$) for 2 h; propofol preconditioning (PPC)/$H_2O_2$, cells pretreated with propofol ($100{\mu}M$) for 2 h were exposed to $H_2O_2$; and 3-methyladenine $(3-MA)/PPC/H_2O_2$, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to $H_2O_2$. Cell viability, apoptosis, and migration capability were evaluated. Relation to autophagy was detected by western blot analysis. Results: Cell viability decreased significantly in the $H_2O_2$ group compared to that in the control group and was improved by propofol preconditioning. Propofol preconditioning effectively decreased $H_2O_2$-induced cell apoptosis and increased cell migration. However, pretreatment with 3-MA inhibited the protective effect of propofol on cell apoptosis. Autophagy was activated in the $PPC/H_2O_2$ group compared to that in the $H_2O_2$ group as demonstrated by western blot analysis and autophagosome staining. Conclusion: The results suggest that propofol preconditioning induces an endogenous cellular protective effect in human keratinocytes against oxidative stress through the activation of signaling pathways related to autophagy.

• The Journal of Korean Medicine
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• v.28 no.2 s.70
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• pp.213-223
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• 2007

Objective : Alzheimer's disease (AD) is a geriatric dementia that is widespread in old age. With an aging populace, AD is a looming problem in public health service. Alzheimer's disease is characterized by specific neuronal degeneration in certain areas of the brain. Mutations and abnormal expression of several genes are associated with ${\beta}-amyloid$ deposits and Alzheimer's disease; among them APP, PS1, and PS2, SOD, free radical, ROS. Methods:We studied herbal medicines that have a relationship to brain degeneration. From pre-modern times, although a variety of oriental prescriptions of Aster tataricus have been traditionally utilized for the treatment of AD, their pharmacological effects and action mechanisms have not yet been fully elucidated. Result : Based on morphological observations by phase-contrast microscope, TUNEL assay and MTT in the culture media, $H_20_2-induced$ cell death was significantly inhibited by Aticus. We examined by ROS formation, catalase activity and GSH activity. We studied the protective effect and inhibitory effects of neurotoxicity in $H_20_2-induced$ PC-12 cells by Aticus. Findings from our experiments show that Aticus inhibits apoptosis, which has neurotoxicities and cell damage in PC-12 cells. In addition, treatment with Aticus ($>25{\mu}g/ml$ for 6hrs) partially prevented $H_20_2-induced$ cytotoxicity in PC-12 cells, and induced a protective effect. Conclusion : As the result of this study, in the Aticus group, the apoptosis in the nervous system was inhibited, protected against the degeneration of PC-12 cells by $H_20_2$. Taken together, Aticus exhibited inhibition of $H_20_2-induced$ apoptotic cell death. Aticus was found to induce protective effect on GSH and catalase in PC-12 cells. Based on these findings, Aticus may be beneficial for the treatment of AD.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.230-237
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• 2017

In this study, electrochemical methods were used to determine the optimum protection potential of S355ML steel for the cathodic protection of offshore wind-turbine-tower substructures. The results of potentiodynamic polarization experiments indicated that the anodic polarization curve did not represent a passivation behavior, while under the cathodic polarization concentration, polarization was observed due to the reduction of dissolved oxygen, followed by activation polarization by hydrogen evolution as the potential shifted towards the active direction. The concentration polarization region was found to be located between approximately -0.72 V and -1.0 V, and this potential range is considered to be the potential range for cathodic protection using the impressed current cathodic protection method. The results of the potentiostatic experiments at various potentials revealed that varying current density tended to become stable with time. Surface characterization after the potentiostatic experiment for 1200 s, by using a scanning electron microscope and a 3D analysis microscope confirmed that corrosion damage occurred as a result of anodic dissolution under an anodic polarization potential range of 0 to -0.50 V, which corresponds to anodic polarization. Under potentials corresponding to cathodic polarization, however, a relatively intact surface was observed with the formation of calcareous deposits. As a result, the potential range between -0.8 V and -1.0 V, which corresponds to the concentration polarization region, was determined to be the optimum potential region for impressed current cathodic protection of S355ML steel.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• Journal of Pharmacopuncture
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• v.13 no.2
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• pp.5-12
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• 2010

Reactive Oxygen Species(ROS) are continuously produced at a high rate as a by-product of aerobic metabolism. Since tissue damage by free radical increases with age, the reactive oxygen species(ROS) such as hydrogen peroxide($H_2O_2$), nitric oxide(NO). Several lines of evidence provided that ROS appears to cause to develop aging-related various diseases such as cancer, arthritis, cardiovascular disease. In this study, we have conducted to investigate the biological activities of Hominis Placenta Herbal Acupuncture by measuring total polyphenol content, DPPH radical scavenging, ABTS radical scavenging, Superoxide dismutase(SOD)-like activity, Nitrite scavenging ability in vitro. The total polyphenol contents of Hominis Placenta Herbal Acupuncture was $24.6m{\ell}/m{\ell}$. Elctron donation ability on DPPH was 49.4%. The 2,2'-azinobis-3-ehtlbezothiazoline-6-sulfonic acid radical decolorization (ABTS) was 50.01%, similar 10 the DPPH free radical scavenging. The superoxide dismutase (SOD)-like activities of hominis placenta herbal acupuncture was 50.876%. The nitrite scavenging abilities at pH 1.5, pH 3.0, pH 6.0 were 52.8%, 29.4%, 15.4%, respectively; these abilities decreased as pH increased. We conclude that Hominis Placenta Herbal Acupuncture may be useful as potential sources of antioxidant.

• Fire Science and Engineering
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• v.31 no.6
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• pp.23-32
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• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.