• Tribology and Lubricants
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• v.31 no.6
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• pp.258-263
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• 2015

Biodiesel is an environmentally-friendly fuel with low smoke emission because it contains about 10% oxygen. Biodiesel fuel prepared by transesterification of vegetable oil or animal fats is susceptible to auto-oxidation. The rate of auto-oxidation depends on the number of methylene double bonds contained within the fatty acid methyl or ethyl ester groups. Biodiesel may be easily oxidized under several conditions, i.e., upon exposure to sunlight, temperature, oxygen environment. Maintenance of the fuel quality of biodiesel requires the development of technologies to increase the resistance of biodiesel to oxidation. Treatment with antioxidants is a promising approach for extending the shelf-life or storage time of biodiesel. The chemical properties of various amine-based antioxidants were evaluated after synthesis of the antioxidants by condensation of phenylenediamine with alkylamines at room temperature. In general, the oxidative stability can be assessed based on various experimental parameters. Such parameters may include temperature, pressure, and the flow rate of air through the samples. The Rancimat method (EN14112) was selected because it is a rapid technique that requires very little sample and provides good precision for oxidative degradation analysis. Specifically, the EN 14112 technique provides enhanced efficiency for oxidative stability evaluation when a larger ester head group is utilized. Therefore, this technique was employed for evaluation of the oxidation stability of biodiesel by the Rancimat method (EN14112).

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1275-1281
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• 2006

This research was planned and executed to evaluate how the nutritional composition and antioxidants contents and antioxidative activity of a composite with Eleutherococcus senticosus and several oriental medicinal herbs . Also, can effect health conditions of people who are suffering from diet-related disease like obesity and hyperlipidemia by taking healthy foods with a composite with Eleutherococcus senticosus and several oriental medicinal herbs in a form of nutritional supplement with our daily meals. With this observation, we found out that a composite with Eleutherococcus senticosus and several oriental medicinal herbs has dietary fiber, Zn, Cu, Fe and water soluble antioxidants and effect on antioxidative activity. We concluded that we could apply the components in a form of various foods. The information we received from this conclusion will be a basic information on how we can apply oriental medicinal resources into other foods and in the field of functional food research, which already draes sizable attention world-wide.

• 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.

• Journal of Soil and Groundwater Environment
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• v.27 no.4
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• pp.37-48
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• 2022

Accurate analysis of petroleum hydrocarbons in soil is an important prerequisite for proper source tracking of contamination. Identification of petroleum compounds is commonly carried out by peak pattern matching in gas chromatography. However, this method has several technical limitations, especially when the soils underwent biological, physical and chemical transformation. For instance, it is very difficult to distinguish jet fuel (JP-8) from kerosene because JP-8 is derivatized from secondary reaction between chemical agents (e.g. anti-oxidants, antifreezer and so on) and kerosene. In this study, an alternative method to separately analyze JP-8 and kerosene in the petroleum hydrocarbon contaminated soil was proposed. Qualitative analyses were performed for representative phenolic antioxidants [2,6-di-tert-butyl phenol (2,6-DTBP), 2,4-di-tert- butylphenol(2,4-DTBP), 2,6-di-tert-butyl-4-methyl phenol (2,6-DTBMP)] using a two dimensional gas chromatograph mass spectrometer (2D GC×GC-TOF-MS). This qualitative analysis of antioxidants in soil would be a useful complementary tool for the peak pattern matching method to identify JP-8 contamination in soil.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.424-433
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• 2017

Antioxidants are used in the manufacturing of commercial food packages made of polyolefin plastic such as polyethylene and polypropylene for the purpose to delay the oxidation reaction of the polymer due to oxygen or traces of ozone in the atmosphere. Additives in plastics may be migrated from the packaging materials into foods, thereby presenting a potential health risk to the consumer. Therefore, it is necessary to determine migration level of antioxidants from food packaging materials to foodstuffs in order to take proactive management. In this study, we have developed a method for the analysis of 10 antioxidants, which are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), Cyanox 2246, 425 and 1790, Irgafos 168, and Irganox 1010, 1330, 3114 and 1076, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The antioxidants were determined by reversed-phase high-performance liquid chromatograph-ultraviolet detector with 276 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.11~0.41 mg/L), and limits of quantification (0.34~1.24 mg/L). The recoveries of antioxidants spiked to four food simulants ranged from 71.3% to 109.4%. The migrated antioxidants in this study were within the safety levels that resulted from the safety assessment by the estimated daily intake to the tolerable daily intake.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.408-412
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• 2008

Determining the elution of water-soluble substances from herbal teas is an important factor in their efficient use in terms of taste, perfume, and content of health-related components. The antioxidant activity and content of catechins in commercial Chrysanthemum indicum (gamguk) teas were determined for optimum elution conditions. The water extract of gamguk teas did not differ significantly in yield compared to methanol extracts and showed stronger antioxidant activity. Catechin contents in gamguk teas were 8-18% of the extracts when individual peaks in high-performance liquid chromatography analysis were compared to standard catechin peaks. Gamguk teas exhibited faster release of antioxidants, and the antioxidant activity was positively correlated with the thermal treatments. Gukhwacha (GC) was the best tea for rapid release (30 sec) of antioxidants with the $50^{\circ}C$ treatment, whereas antioxidants in other teas were relatively slower released.

• Journal of environmental and Sanitary engineering
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• v.21 no.1 s.59
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• pp.52-57
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• 2006

Metallothioneins(MTs) belong to the class of low molecular weight proteins. Recently, it has been suggested that MTs may playa direct role in cellular defense against oxidative stress by functioning as antioxidants. Oxidative damage to different cellular components makes a major contribution to many pathogenenesses. Several studies have demonstrated that MT is able to quench a wide range of reactive oxygen species at a higher efficiency than other well known antioxidants such as superoxide dismutate(SOD). The present study was designed to evaluate the effect of MT on the activities of the reactive oxygen species removal system. MT showed the scavenging of superoxide in the SOD assay system in the presence or absence of SOD. When MT was added to nicotinamide adenine dinucleotide phosphate(NADPH) oxidation system in presence of fixed amount of SOD increase the breakdown rate of superoxide. When MT was added to the system that form nitrite from hydroxylammonium chloride, the formation of nitrite was inhibit. We concluded that the function of MT as antioxidant might have an effect on the level of superoxide scavenging.

• KSBB Journal
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• v.19 no.5
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• pp.374-380
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• 2004

Production of therapeutic proteins by transgenic plant cell suspension cultures is an attractive system alternative to the other expression system. However, plant cell cultures have shown low expression level of foreign proteins and decreased cell viability by the changes of culture conditions. Therefore, it is necessary to enhance cell viability during the culture period. In this study, a quantitative analysis technique was designed to measure relative cell viability for plant suspension cells which have cell wall and aggregates. It was found that the programmed cell death of plant cells by apoptosis was essentially linked with the apoptotic pathway of animal cells. Therefore, effects of nicotinamide, 3-aminobenzamide and antioxidants on cell viability and apoptosis were examined in transgenic Nicotiana tabacum cells producing hGM-CSF. With those additives, cell viability could be maintained and apoptosis could be redued. In the result, the extracellular production of hGM-CSF could be enhanced 2.5 fold. It was also found that the supplementation of glutathione and ascorbic acid suppressed both the cold stress-induced decrease in cell viability and the increase of total genomic DNA fragmentation.

• Food Science and Preservation
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• v.6 no.1
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• pp.121-135
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• 1999

Effective synthetic antioxidants such as butylated hydroxyanisole(BHA) and butylated hydroxytoluene(BHT) have been widely used in the food industry, but they are suspected to be toxic and carcinogenic effects. Therefore, the development of safely available natural antioxidants such as ascorbic acid, ${\alpha}$-tocopherol, ${\beta}$-carotene, flavonoids and selenium is essential. In particular, flavonoids, 2-phenyl-benzo-${\alpha}$-pyrones, are polyphenolic compounds that occur ubiquitously in food of plant origin. flavonoids occur in foods generally as O-glycosides with sugars bound usually at the C\ulcorner position. And variations in their heterocyclic ring gibes rise to flavones, flavonols, flavanones, flavanols, catechins, anthocyanidins, chalcone and isoflavones. Vegetables, fruits, and beverages are the main dietary sources of the flavonols, primarily as quercetin, kaempferol, and myricetin and the corresponding flavones, apigenin and luteolin. These flavonoids have biological activity such as antioxidant, anti-inflammatory, antithrombotic, antimutagenic, anticarcimogenic antiallergic and antimicrobial activity effects in vitro and in vivo. Flavonoids posses strong antioxidant activities acting as oxygen radicals scavenger, metal chelators and enzyme inhibitor. The antioxidant activity of flavonoids is determined by their molecular structure and more specially, by the position and degree of hydroxylation of the ring structure. All flavonoids with the 3`, 4`-dihydroxy(ortho-dihydroxy) posses marked antioxidant activity. And antioxidant activity increases with the number of hydroxyl groups substituted on the A-and B-rings. There is as yet no certainty about the effect of the presence of a double bond between C\ulcorner and C\ulcorner on the antioxidant activity of flavonoids.

• Journal of Periodontal and Implant Science
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• v.44 no.4
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• pp.207-213
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• 2014

Purpose: The study was aimed at investigating changes in periodontal parameters and superoxide dismutase activity triggered by root surface debridement with and without micronutrient supplementation in postmenopausal women. Methods: Forty-three postmenopausal chronic periodontitis patients were divided into two groups: group 1 (n=22) were provided periodontal treatment in the form of scaling and root planing (SRP) and group 2 (n=21) patients received SRP along with systemic administration of micronutrient antioxidants. Patients in both groups were subjected to root surface debridement. Group 2 patients also received adjunctive micronutrient antioxidant supplementation. Serum and salivary superoxide dismutase (SOD) activity along with periodontal parameters were recorded at baseline and 3 months after therapy. Results: Salivary and serum SOD values significantly (P<0.05) improved with periodontal treatment. Improvement in systemic enzymatic antioxidant status along with reduction in gingival inflammation and bleeding on probing (%) sites was significantly greater in group 2 as compared to group 1. Conclusions: Adjunctive micronutrient supplements reduce periodontal inflammation and improve the status of systemic enzymatic antioxidants in postmenopausal women.