• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1340-1349
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• 2012

Increasing the oxidation of fat through exercise is the recommendable method for weight control. Preceding researches have proposed increase in the usage of fat during exercise in stabilized state and under maximum exertion through aerobic training. However, such researches require additional equipment for gas analysis in order to measure the caloric value or gas exchange of subjects during exercise. Such equipments become highly restrictive for those exercise and cause substantially higher cost. According to this, we have presented the method of estimating the maximal fat oxidation point through changes in LF & HF which reflects changes in heart rate and the autonomic nervous system in order to induce exercise for a less restrictive and efficient fat oxidation than existing methods. We have conducted exercise stress test on subject with similar exercise abilities, and have detected the changes in heart rate and changes in LF & HF by measuring changes in fat oxidation and measuring ECG signals at the same time through a gas analyzer. Changes in heart rate and HRV of the subjects during exercising was detected through only the electrocardiographic signals from exercising and detected the point of maximum fat oxidation that differs from person to person. The experiment was carried out 16 healthy males, and used Modified Bruce Protocol, which is one of the methods of exercise stress test methods that use treadmill. The fat oxidation amount during exercise of all the subjects showed fat oxidation of more than 4Fkcal/min in the exercise intensity from about 5 minutes to 10 minutes. The correlation between the maximal fat oxidation point obtained through gas analysis and the point when 60% starts to be relevant in the range from -0.01 to 0.01 seconds for values of R-R interval from changes in heart rate had correlation coefficients of 0.855 in Kendall's method and in Spearman's rho, it showed significant results of it being p<0.01 with 0.950, respectively. Furthermore, in the changes in LF & HF, we have determined the point where the normalized area value starts to become the same as the maximal fat oxidation point, and the correlation here showed 0.620 in Kendall and 0.780 in Spearma of which both showed significant results as p<0.01.

• Environmental Mutagens and Carcinogens
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• v.16 no.1
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• pp.13-18
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• 1996

One mechanism of free-radical production by ethanol is suggested to be through the intracellular conversion of XDH to XO by increased ratio of NADH to NAD. The major mechanism for physiological compensation of cytosolic NADH/NAD balance is the malate/aspartate shutfie. Therefore, it is important to develop the method to improve the efficiency of malate/aspartate shuttle in ethanol metabolism. In the present study, various amino acids and organic acid involved in the shuttle were tested for their functional efficiency in modulating shuttle in the ethanol-perfused rat liver. The rate of ethanol oxidation in the liver perfused with aspartate alone or aspartate in combination with pyruvate, respectively, was increased by about 10% compared to control liver, but not in the tissues perfused with glummate, cysteine or pyruvate alone. Though glummate, cysteine and pyravate did not affect the ethanol oxidation significanfiy, they showed some suppresive effect on the ethanol-induced radical generation monitored by protein carbonylation analysis. Among the tested components, aspartate is confirmed to be the most efficient as a metabolic regulator for both ethanol oxidation and ethanol-induced oxidative stress in our perfusion system. These effects of aspartate would result from NAD recycling by its supplementation through the coupled aspartate aminotransferase/malate dehydrogenase reactions and the malate-aspartate shuttle.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.92-99
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• 2011

Topical natural antioxidants are a useful strategy for the prevention of oxidative stress mediated cardiovascular disease including atherosclerosis. From the viewpoint of this underlying principle, the screening of natural plant extracts with scavenging activity for pro-oxidant reactive species is a primary requirement for the development of new topical antioxidant formulations. Euryale ferox Salisbury (EF) is botanical name and it's pharmaceutical name is EURYALES SEMEN (ES). The stems and branchs of EF have been used as a traditional herbal medicine for the treatment of dysentery, diarrhea, leucorrhoea, incontinence and paralysis of joint. In this study, the antioxidant activity of extract from EF was studied in vitro methods by measuring the antioxidant activity and free radical scavenging activity by TEAC and DPPH, measuring the scavenging effects on reactive oxygen species (ROS) [superoxide anion, hydroxyl radical] and on reactive nitrogen species (RNS) [nitric oxide and peroxynitrite] as well as measuring the inhibitory effect on $Cu^{2+}$-induced human LDL oxidation. The EF extracts were found to have a potent scavenging activity, as well as an inhibitory effect on LDL oxidation. In conclusion, the EF extracts have antioxidative effects in vitro system, which can be used for developing pharmaceutical drug against oxidative stress and chronic degenerative disease such as atherosclerosis.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.103-109
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• 2008

Purpose: This review illustrates an importance of oxidative stress caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation in association with eye disease, especially of cataract, and discusses an important role of lipid peroxide as a mediator of oxidative stress-related ocular dysfunction. Methods: Oxidative stress, resulted from the cellular production of ROS and RNS, is known to cause various forms of cellular damages such as protein oxidation, DNA breaks, apoptosis, and lipid peroxidation. These damages can be developed to human diseases. Accumulating evidence strongly suggests that continuous or constant exposure of eye tissues to oxidative stress is a main cause of cataractogenesis. Therefore, we investigated the action of oxidative stress in ocular dysfunction. Results: The ocular lens is continuously attacked by ROS inevitable generated from the process of cellular metabolism and the chronic exposure to ultraviolet. Excessive generation of ROS, resulting in degradation, oxidation, crosslinking and aggregation of lens proteins, is regarded as an important factor in development of cataract. Conclusions: These oxidative stress and oxidant/antioxidant imbalance produces the excess ROS which can lead to eye dysfunction. Even though known results, it should be noted that there is limited information on the molecular mechanism which can be better defined with the interrelation of oxidative stress and optic abnormalities.

• Nutritional Sciences
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• v.9 no.4
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• pp.288-294
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• 2006

In this study, the effects of smoking cessation and relative antioxidant activities on the oxidative stress were determined by using in vitro method. Thirty healthy smokers who were free of any disease and smoked more than 1 pack per day for the past 10 years participated in this study. For smoking cessation, smokers were asked to wear nicotine patch (21mg nicotine/ patch) everyday for 30 days and then to replace at the same time of the day. Smoking cessation program in conjunction with nicotine patch replacement was also conducted every week, one hour/each session, for 4 weeks. Canthaxanthin, $\beta-carotene$, and $\alpha-tocopherol$ were added into red blood cells at pre and post smoking cessation. As indicators of oxidative stress, hemoglobin degradation, lipid peroxidation, and percent hemolysis were determined at both pre and post smoking cessation. After 30 days of smoking cessation, the subjects gained an average of 5 pounds, varying 2 to 8 pounds, by suggesting that behavioral problems rather than nicotine itself are more important for gaining weight in ex-smokers. The total hemoglobin concentrations in blood were similar in pre and post smoking cessation, but smoking cessation resulted in a decrease in the percentage of methemoglobin from 0.96% to 0.85% Smoking cessation also caused to decease malondialdehyde (MDA) values ($26.7{\pm}7.8$ vs. $23.6{\pm}4.5$ (without oxidation), $179.3{\pm}21$ vs. $161.2{\pm}28$ nmol/ml (with oxidation) (p<0.05)), not percent hemolysis. Various antioxidants with smoking cessation significantly decreased MDA values(p<0.05), in contrast to marginal decrease of MDA in smoking cessation only. Three antioxidants used in this stu study were similarly effective in inhibiting MDA production, but relative effectiveness of canthaxanthin or $\alpha-tocopherol$ was greater than that of $\beta-carotene$ (p<0.05), in case of oxidation induced. The percent hemolysis was greatly decreased when antioxidants were added into the blood of ex-smokers (p<0.05) but no statistical significance in relative effectiveness of antioxidants was observed.

• Analytical Science and Technology
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• v.5 no.4
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• pp.359-366
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• 1992

Using micro-Raman spectrometer, we investigated the evaluation of microstress on silicon surface after the local thermal oxidation. The induced stress of silicon surface after local thermal oxidation shows maximum value at the interface of silicon oxide and active area. The smaller the size of active area, the larger stress. From the evaluation of three other device isolation processes, A, B and moB, whose active size has $0.45{\mu}m$ in length, moB process is turned out to have the lowest stress value and the smallest bird's beak effect.

• Journal of Oriental Neuropsychiatry
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• v.23 no.1
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• pp.115-128
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• 2012

Objectives : To evaluate the in vitro scavenging activity, inhibitory effect of LDL oxidation of pro-oxidant reactive species, anti-platelet aggregative effects and anti-thrombosis effects in response to treatment with SA using various screening methods including biological and non-biological oxidants. Methods : The antioxidant activity concerning extract from SA was studied with in vitro methods by measuring the antioxidant activity by TEAC, measuring the scavenging effects on reactive oxygen species (ROS) [superoxide anion, hydroxyl radical] and on reactive nitrogen species (RNS) [nitric oxide and peroxynitrite] as well as measuring the inhibitory effect on $Cu^{2+}$-induced human LDL oxidation and the inhibitory effect on thrombin-induced platelet aggregation and thrombosis. Results : SA extracts were found to have a potent scavenging activity regarding oxidative stress as well as an inhibitory effect towards LDL oxidation, platelet aggregation, and thrombosis. Conclusions : The SA extracts have anti-oxidative and anti-atherosclerotic effects in vitro system, which can be used for developing pharmaceutical drugs against oxidative stress and atherosclerosis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.862-866
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• 2012

Surface passivation of AlGaN/GaN heterojunction structure was examined through the thermal oxidation of evaporated Al. The Al-oxide passivation increased channel conductance of two dimensional electron gas (2DEG) on the AlGaN/GaN interface. The sheet resistance of 463 ohm/${\Box}$ for 2DEG channel before $Al_2O_3$ passivation was decreased to 417 ohm/${\Box}$ after passivation. The oxidation of Al induces tensile stress to the AlGaN/GaN structure and the stress seemed to enhance the sheet carrier density of the 2DEG channel. In addition, the $Al_2O_3$ films formed by thermal oxidation of Al suppressed thermal deterioration by the high temperature annealing.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.243-246
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• 1999

We studied the MOSFET characteristics and the hot-carrier reliability with the sidewall spacer composition and the post gate oxidation thickness in 0.20${\mu}{\textrm}{m}$ gate length transistor. The MOSFET with NO(Nitride＋Oxide) sidewall spacer exhibits the large degradation of hot-carrier lifetime because there is no buffering oxide against nitride stress. When the post gate oxidation is skipped, the hot-carrier lifetime is improved, but GIDL (Gate Induced Drain Leakage) current is also increased.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.406-413
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• 2023

This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni₃Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.