• Corrosion Science and Technology
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• 제21권2호
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• pp.147-157
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• 2022

Electrochemical characteristics and damage behavior of 6061-T6 aluminum alloy used as a battery housing material for electric vehicles were investigated in solution simulating the acid rain environment with chloride concentrations. Potentiodynamic polarization test was performed to analyze electrochemical characteristics. Damage behavior was analyzed through Tafel analysis, measurement of damage area, weight loss, and surface observation. Results described that corrosion current density was increased rapidly when chloride concentration excceded 600 PPM, and it was increased about 7.7 times in the case of 1000 PPM compared with 0 PPM. Potentiodynamic polarization experiment revealed that corrosion damage area and mass loss of specimen increased with chloride concentrations. When chloride concentration was further increased, the corrosion damage area extended to the entire surface. To determine damage tendency of pitting corrosion according to chloride concentration, the ratio of damage depth to width was calculated. It was found that the damage tendency decreased with chloride concentrations. Thus, 6061-T6 aluminum alloy damage becomes larger in the width direction than in the depth direction when a small amount of chloride is contained in an acid rain environment.

• 한국환경성돌연변이발암원학회지
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• 제20권1호
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• pp.7-13
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• 2000

The mechanisms of benzene toxicity is not fully elucidated, although the metabolism of benzene is very well understood. In order to study the mechanism of benzene toxicity, we investigated DNA damage induced by benzene metabolite, 1,2,4-benzenetriol (BT) in HL-60 cells by alkaline comet assay. To investigate the mechanism of cellular DNA damage induced by BT, the cells were treated with antioxidant such as vitamin C, SOD, catalase, and chelating agent such as deferoxamine (DFO), bathocuproinedisulfonic acid (BCDS). BT induced DNA damage in dose-dependent manner at concentration between 10$\mu\textrm{m}$ and 100$\mu\textrm{m}$. The antioxidant vitamin C itself induced DNA damage at higher concentration. The DNA damage induced by BT in HL-60 cells was protected at low concentraiton of vitamin C whereas no protective effect was found at high concentration. In hibitory effect of SOD on DNA damage by BT was observed and this suggested that BT produce superoxide anion (O2-) causing DNA damage. Catalase protected BT-induced DNA damage suggesting that BT produce H2O2 during autooxidation of BT. Both Fe(II)-specific cheiating agent, deferoxamine (DFO) and Cu(I)-specific chelating agent, bathocuproinedisulfonic acid (BCDS) inhibited BT0induced DNA damage. This suggested that DNA damage was caused by active species which was produced DAN damage. This suggested that DNA damage was caused by active species which was produced by the autooxidation of BT in the presence of Cu(II) and Fe(III). These findings suggest that reactive oxygen species play an important role in the mechanism of toxicity induced by benzene metabolites.

• Preventive Nutrition and Food Science
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• 제17권2호
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• pp.116-121
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• 2012

Water extract from Pinus densiflora (WPD) was investigated for its antioxidant activity and its ability to provide protection from DNA damage. A series of antioxidant assays, including a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging assay, a reducing power assay, a metal-chelating assay, a superoxide radical scavenging assay, and a nitrite scavenging ability, as well as a DNA damage protection assay were performed. Total phenolic content was found to be 211.32 mg Tan/g WPD. The extract scavenged 50% DPPH free radical at a concentration of 21.35 ${\mu}g/mL$. At that same concentration, the reducing power ability of WPD was higher than that of ${\alpha}$-tocopherol. The extract chelated 68.9% ferrous ion at the concentration of 4 mg/mL. WPD showed better nitrite scavenging effect at the lower pH. Meanwhile, WPD exhibited a strong capability for DNA damage protection at 1 mg/mL concentration. Taken together, these data suggest water extract from Pinus densiflora could be used as a suitable natural antioxidant.

• Toxicological Research
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• 제29권1호
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• pp.43-52
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• 2013

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

• Journal of Microbiology and Biotechnology
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• 제28권4호
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• pp.527-533
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• 2018

This study compared the radioprotective effects of high-molecular-weight poly-gamma-glutamate (${\gamma}-PGA$, average molecular mass 3,000 kDa) and a reduced form of glutathione (GSH, a known radioprotector) on calf thymus DNA damage. The radiation-induced DNA damage was measured on the basis of the decreased fluorescence intensity after binding the DNA with ethidium bromide. All the experiments used $^{60}Co$ gamma radiation at 1,252 Gy, representing 50% DNA damage. When increasing the concentration of ${\gamma}-PGA$ from 0.33 to $1.65{\mu}M$, the DNA protection from radiation-induced damage also increased, with a maximum of 87% protection. Meanwhile, the maximal DNA protection when increasing the concentration of GSH was only 70%. Therefore, ${\gamma}-PGA$ exhibited significant radioprotective effects against gamma irradiation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.109-110
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• 2020

In the event of a fire, fire engines usually arrive within 15 minutes and become a fire suppressor. In this paper, an analytical model was established to evaluate the salt damage resistance of concrete according to fire suppression time, and the concentration of salt inside the concrete after fire was measured and the time to reach the critical concentration was assessed by how short.

• 한국산업보건학회지
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• 제24권3호
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• pp.336-344
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• 2014

Objectives: This study was performed to assay the effect of neodymium oxide on the generation of reactive oxygen species and DNA oxidative damage by intratracheal instillation. Methods: Two groups of rats were exposed to neodymium oxide($Nd_2O_3$) via intratracheal instillation with doses of 0.5 mg and 2.0 mg, respectively. At two days and at 12 weeks after exposure, the contents of neodymium oxide in the lung, liver, kidney, heart and brain, leukocyte, olive tail moment, ROS, RNS, lactate dehydrogenase, albumin, cytokine and MDA from BALF were measured. Results: Neodymium oxide contents in the liver, kidney, heart, and brain were detected at less than $1{\mu}g/g$ tissue concentration. However, in the lungs at four weeks the highest amount were detected and then found to be drastically reduced at 12 weeks. ROS and RNS in bronchoalveolar lavage increased in concentration dependently at two days, four weeks and 12 weeks after neodymium oxide instillation. However, ROS and RNS decreased with the passage of time. At two days the total number of WBC in BALF in the high concentration group was significantly increased, and at four weeks the total number of WBC were significantly increased in the low and high concentration groups(p<0.01). At two days after exposure, the LDH of the low and high concentration groups was significantly increased. At 12 weeks, only the LDH of the high concentration group was significantly increased compared to in the control group(p<0.01). As a result of Comet assay, after two days, damage to the DNA of the low and high concentration groups was observed. Conclusions: Intratracheal instillation of neodymium oxide induces the generation of ROS and DNA damage in rats.

• 한국패션뷰티학회지
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• 제5권1호
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• pp.71-77
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• 2007

This study attempted to comparative analysis about the physical and morphological damage degrees of hair according to the bleaching methods by $H_2O_2$ concentration. As a result of the changes in the physical characteristics of the hair according to the deceleration operation methods by 3-6-9% and 9% $H_2O_2$ concentration, the intensity of tension considerably decreased but the elongation was increased. And the more the damage of hair, the larger the degree of change. Regarding the method of deceleration operation, the 3-6-9% deceleration operation method was more damaging than the 9% single deceleration operation method. In the change of the characteristics of the form of the hair, the control group of the 5-level deceleration hair generally showed a smooth external appearance and regular and closely overlapped epidermis and undamaged cuticle were observed. But in the 3-6-9% deceleration operation method and 9% single deceleration operation method, damages such as the irregular form of the edge of the epidermis and the unclear boundary between the epidermis occurred.

• 한국의상디자인학회지
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• 제24권4호
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• pp.1-9
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• 2022

The purpose of this research is to improve sustainable clothes care by comparing household washer's standard course and quick course. Detergency at each course was classified by laundry weight, detergent concentration, and soils. Also, fabric damage from each course was compared. Washing experiments were carried out using two types of washing machines and three types of detergents. Using the standard soiled fabrics of EMPA 108 set, detergency was compared by laundry weight, soil, and detergent concentration. Additionally, fabric damage was evaluated using the mechanical action of MA-40. The results of the research were as follows. First, a standard course, having more working time exhibited better detergency than a quick course. However, the detergency deviation under 6kg laundry weight was as low as 9.0%. Second, detergency by the type of soil was more effective in standard course than in a quick course, but hydrophilic protein soils had a small detergency deviation at 7.6%. Moreover, hydrophobic oil, complex, and particulate soils had a higher deviation at 19.7% Third, fabric damage was in proportion to operating time. Fourth, a quick course showed approximately 80% detergency regardless of the type of detergent. in the case of using 50% of the recommended allowance by the detergent manufacturer. In conclusion, reducing the operating washing time and detergent concentration is in accordance with increasing sustainability, in the case of washing with lightly soiled fabrics under 6kg of laundry weight.

• Journal of Nutrition and Health
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• 제33권2호
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• pp.167-178
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• 2000

The effect of oral vitamin e (800IU/day) and C (500mg/day) supplementation for 10 days and/or smoking cessation for 5 days on oxidative damage to the red blood cells (RBC) of male smokers (22.2$\pm$0.2 years old) was studied. RBC were tested for their ability to protect against smoking-induced oxidative damage by measuring heme proteins (carboxyhemoglobin, hemoglobin, methemoglobin, oxyhemoglobin), hemolysis and thiobarbiturinc acid reactive substances (TBARS). Plasma levels of vitamin c, A, E, $\beta$-catotene, total cholesterol, glutamic pyruvic transaminase(GPT) and glutamic oxaloacetic transaminase(GOT) were also analyzed. In experiment one, a comparison was made of heme proteins and lipid damage to RBC, plasma antioxidant status (indexed by plasma levels of vitamin C, E, A and $\beta$-carotene) between smokers(n=56) and non-smokers (n=16). No differences were found in plasma antioxidant status, heme protein damage and TBARS concentration of RBC. In experiment two, 46 fasting male smokers from experiment one were divided into 4 groups. The groups were smoking with placebo group(SP, n=14), smoking cessation with vitamins supplementatin group (SV, n=13), smoking cessation with placebo group (NSP, n=9) and smoking cessation with vitamins supplementation group (NSV, n=10). After supplementing antioxidant vitamins, significant increases were seen in plasma vitamins supplementation group (NSV, n=10). After supplementing antioxidant vitamins, significant increases were seen plasma vitamin C (p<0.05) and vitamin E levels (p<0.05). The plasma vitamin E level was highest in the NSV group. Vitmain E and C supplementation provided some protection against heme proteins and lipid damage by lowering methemoglobin, hemolysis and TBARS concentration of RBC. Smoking cessation significantly decreased TBARS of RBC and plasma total cholesterol concentration. Supplementing vitamin E and C with smoking cessation considerably lowered plasma total cholesterol. These results point to a special association among smoking, oxidative damage and plasma antioxidant vitamin status. They indicate that increases in plasma antioxidant status can be detected after the supplementation of vitamin C and E and that smoking cessation had an additional effect on plasma vitamin E level. The present data suggest that improved antioxidant status induced by antioxidant supplementation or smoking cessation may help prevent oxidative damage in smokers.