• Analytical Science and Technology
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• v.14 no.1
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• pp.80-87
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• 2001

This research was studied the action of the coupling ozone-hydrogen peroxide on aqueous humic acid. PEROXONE process is enhanced the generation of hydroxyl radicals which is effective for degradation of organic matters. Therefore the changes of $UV_{254}$ and TOC were investigated through the change of concentrations, injection time of $H_2O_2$, initial pH of aqueous humic acid and concentrations of radical savenger as $HCO_3{^-}$ in the PEROXONE processes. And the GC/ECD was used to detect the formaldehyde formed by ozonation of humic acid. From the experimental results, concentrations and injection time of $H_2O_2$ and initial pH in solution in the PEROXONE processes were very important for enhancing the efficiency of degradation in humic acid. The results indicated that removal efficiency of TOC was the highest when concentration of $H_2O_2$ was 5mg/L, injection time of $H_2O_2$ was 5 minutes and initial pH in solution was 10.5. And presence of alkalinity in solution was reduced the efficiency of treatment. The formaldehyde were formed less PEROXONE processes than only ozone. When initial pH in solution were changed from 3.5 to 10.5, the formaldehyde were formed highest concentration at pH 5.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3537-3538
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• 2013

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.56-61
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• 2023

The germination process is critical for plant growth and development and it is largely affected by environmental stress, especially salinity. Recently, hydrogen sulfide (H₂S) is well known to act as a signaling molecule in a defense mechanism against stress conditions but poorly understood regulating seed germination. In this study, the effects of NaHS (the H₂S donor) pretreatment on various biochemical (hydrogen peroxide (H₂O₂) content and amylase and protease activity) and physiological properties (germination rate) during seed germination of oilseed rape (Brassica napus L. cv. Mosa) were examined under salt stress. The seed germination and seedling growth of oilseed rape were inhibited by NaCl treatment but it was alleviated by NaHS pretreatment. The NaCl treatment increased H₂O₂ content leading to oxidative stress, but NaHS pre-treatments maintained much lower levels of H₂O₂ in germinating seeds under salt stress. Amylase activity, a starch degradation enzyme, significantly increased over 2-fold in control, NaHS pretreatment, and NaHS pretreatment under NaCl during seed germination compared to NaCl treatment. Protease activity was highly induced in NaHS-pretreated seeds compared to NaCl treatment, accompanied by a decrease in protein content. These results indicate that NaHS pretreatment could improve seed germination under salt stress conditions by decreasing H₂O₂ accumulation and activating the degradation of protein and starch to support seedling growth.

• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.29-32
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• 2005

Chemical mechanical polishing is an essential process in the production of copper-based chips. On this work, the stability of hydrogen peroxide ($H_{2}O_{2}$) as an oxidizer of copper CMP slurry has been investigated. $H_{2}O_{2}$ is known as the most common oxidizer in copper CMP slurry. But $H_{2}O_{2}$ is so unstable that its stabilization is needed using as an oxidizer. As adding KOH as a pH buffering agent, stability of $H_{2}O_{2}$ decreased. However, $H_{2}O_{2}$ stability in slurry went up with putting in small amount of BTA as a film forming agent. There was no difference of $H_{2}O_{2}$ stability between pH buffering agents KOH and TMAH at similar pH value. Addition of $H_{2}O_{2}$ in slurry in advance of bead milling led to better stability than adding after bead milling. Adding phosphoric acid resulted in the higher stability. Using alumina C as an abrasive was good at stabilizing for $H_{2}O_{2}$.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.497-508
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• 2020

In this study, we investigated the protective effects of 'Donganme' (Sorghum bicolor L. Moench) against oxidative stress under in vitro conditions and in a cellular system using C6 glial cells. The radical scavenging activities were observed using the substrates 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (•OH) radicals. The Donganme extract had an •OH radical scavenging activity of 82.66% at a concentration of 100 ㎍·mL^-1. Additionally, when DPPH was used as the substrate, the Donganme extract exhibited a strong radical scavenging activity in a concentration-dependent manner with an IC₅₀ value of 28.56 ㎍·mL^-1. Furthermore, treating C6 glial cells with hydrogen peroxide (H₂O₂) reduced the cell viability and generated reactive of oxygen species (ROS) and lactate dehydrogenase (LDH) compared to the normal levels, indicating that H₂O₂ induced oxidative stress. However, Donganme extracts increased the cell viability and inhibited ROS and LDH production against oxidative stress by H₂O₂ in the C6 glial cells. In particular, it showed effective cell protection with the cell viability, ROS production, and LDH release at 83.50, 88.06, and 14.87%, respectively, which were lower than the control or similar to the normal levels even at a low concentration of 100 ㎍·mL^-1. The present study suggests that the Donganme extract was effective in protecting against oxidative stress in C6 glial cells through its antioxidant activity. Thus, Donganme could be a promising therapeutic agent for neurodegenerative diseases due to oxidative stress.

• Environmental Mutagens and Carcinogens
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• v.19 no.2
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• pp.116-121
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• 1999

Quercetin and its glycosides showed a strong free radical scavenging effect to DPPH radical generation. However, there were not big differences between quercetin aglycone and glycosides under experimental condition of this study. On the other hand, quercetin had pro-oxidant effect in bleomycin-dependent DNA assay. Quercetin aglycone and its glycosides, quercitrin inhibited $H_2$$O_2$- induced DNA damage in CHL cells. They also have an anticlastogenicity toward DNA breakage agent by radical generation like bleomycin. These results indicate that quercetin aglycone and its glycosides are capable of protecting the free radical generation induced by reactive oxygen species like $H_2$$O_2$. The mechanism of inhibition in hydrogen peroxide-induced genotoxicity may be due to their free radical scavenging properties. Therefore, quercetin aglycone and its glycosides may be useful chemopreventive agents by protecting of free radical generation which are involved in carcinogenesis and aging. However, quercetin and its glycosides must also carefully examined for pro-oxidant properties before being proposed for use in vivo.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.556-563
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• 2005

Homogentisic acid was found to scavenge intracellular reactive oxygen species (ROS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and thus prevented lipid peroxidation in human fibroblast (Wl 38) cells. The radical scavenging activity of homogentisic acid was found to protect Wl 38 cells against hydrogen peroxide $(H_2O_2)$ induced oxidative stress, via the activation of extracellular signal regulated kinase (ERK) protein. Homogentisic acid increased the activity of catalase. Hence, from the present study, it is suggested that homogentisic acid protects Wl 38 cells against $H_2O_2$ damage by enhancing the intracellular antioxidative activity.

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.499-502
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• 2019

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which is activated in response to DNA damage, and which mediates DNA repair. PARP inhibitors can be used to reduce resistance of cancer cells to anticancer treatments. The objective of this study was to investigate the effects of selected phytochemicals and fruit extracts on PARP activation in MCF-7 breast cancer cells subjected to oxidative stress. Pre-incubation with epigallocatechin gallate (EGCG), apple extract (AE), cranberry extract (CE), or grape extract (GE) for 2 hours at test concentrations reduced PARP activity induced upon treatment with hydrogen peroxide in a dose-dependent manner (p<0.05). GE was found to be the most efficient PARP inhibitor among the fruit extracts examined. These results suggest that phytochemicals of fruit extracts might be used as PARP inhibitors in order to assist anticancer agents.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.151-157
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• 2009

Objectives : The purpose of this study is to investigate the effect of Water Extract from Artemisiae Argi Folium (WAAF) on mouse macrophage Raw 264.7 cells stimulated by lipopolysaccharide (LPS). Methods : Cell viabilities were measured by MTT assay. And the intracellular productions of hydrogen peroxide (H2O2) were measured by dihydrorhodamine 123 assay. TNF-$\alpha$ and IL-6 production from Raw 264.7 were measured by ELISA method. Results : The results of the experiment are as follows. 1. WAAF significantly increased the cell viability compared to the control group (treated with LPS only) at the concentrations of 10, 50, 100, 200, 400 ug/mL. 2. WAAF significantly increased the intracellular production of H2O2 compared to the control group at the concentrations of 50, 100, 200 ug/mL. 3. WAAF significantly decreased the production of TNF-$\alpha$ compared to the control group at the concentrations of 100, 200 ug/mL. 4. WAAF significantly decreased the production of IL-6 compared to the control group at the concentrations of 50, 100, 200 ug/mL. Conclusions : WAAF could be supposed to have the immune-modulating activity related with the macrophage's immunoactivity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.74-79
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• 2007

Most studies on copper Chemical Mechanical Planarization (CMP) have focused on material removal and its mechanisms. Although many studies have been conducted on the mechanism of Cu CMP, a study on uniformity in Cu CMP is still unknown. Since the aim of CMP is global and local planarization, the approach to various factors related to uniformity in Cu CMP is essential to elucidate the Cu CMP mechanism as well. The main purpose of the experiment reported here was to investigate and mechanically analyze the roles of slurry components in the formation of the uniformity in Cu CMP. In this paper, Cu CMP was performed using citric acid($C_{6}H_{8}O_{7}$), hydrogen peroxide($H_{2}O_{2}$), colloidal silica, and benzotriazole($BTA,\;C_{6}H_{4}N_{3}H$) as a complexing agent, an oxidizer, an abrasive, and a corrosion inhibitor, respectively. All the results of this study showed that within-wafer non-uniformity(WIWNU) of Cu CMP could be controlled by the contents of slurry components.