• Title, Summary, Keyword: $H_2O-H_2$-pretreatment

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A Effect of H2O-H2 Pretreatment on VOCs Oxidation over Noble Catalysts on Titania (티타니아에 담지된 귀금속촉매의 H2O-H2 전처리에 따른 휘발성유기화합물 산화에 미치는 영향)

  • Kim, Moon-Chan;Ko, Sun-Hwan
    • Applied Chemistry for Engineering
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    • v.18 no.6
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    • pp.552-556
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    • 2007
  • In this study, noble metals (Pd, Ru, Ir) were supported to $TiO_2$ catalyst. In order to distribute metals uniformly, $H_2O-H_2$ pretreatment technique was used. Xylene, toluene, and MEK were used as reactants. The monometallic or bimetallic catalysts were prepared by the excess wetness impregnation method and were characterized by XRD, and XPS analysis. Pd-Ru, Pd-Ir bimetallic catalysts had multipoint active sites which improved the range of Pd metal state. Bimetallic catalysts had a higher conversion of VOCs than that of monometallic one. The effect of $H_2O-H_2$ pretreatment technique was the enhancement of uniform distribution of Pd particles and promotion of catalytic efficiency. In this study, addition of Ru and Ir metals to Pd promoted oxidation conversion of VOCs. In addition, $H_2O-H_2$ pretreatment promoted removal efficiency of VOCs on the $TiO_2$ support.

A Study on the Treatment of Dyeing Wastewater Using $TiO_2/H_2O_2/UV$ Processes ($TiO_2/H_2O_2/UV$ 공정을 이용한 염색폐수처리에 관한 연구)

  • 조일형;정효준;박경렬;성기석;이용규;이홍근
    • Journal of environmental and Sanitary engineering
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    • v.15 no.4
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    • pp.26-34
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    • 2000
  • In order to treat the dyeing wastewater, the $UV/TiO_2/H_2O_2$ system was investigated, and proper pretreatment methods were examined to reduce the load on the system considering economical and technical efficiency. The results of this study were as follows: 1. $UV/TiO_2/H_2O_2$ system with pretreatment process was adopted, the result of Chemical coagulation and pH control units was $pH{\;}11{\;}{\rightarrow}{\;}coagulation{\;}{\rightarrow}{\;}pH{\;}4$ and the optimum dosage of $FeCl_3$ was $600mg/{\ell}$. 2. Proper dosage of $TiO_2$ in the $UV/TiO_2/H_2O_2$ system with pretreatment process was $2g/{\ell}$ and $H_2O_2$ was $1000mg/{\ell}$, UV contact time was 20min to get $200mg/{\ell}$ of $COD_{Cr}$.

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Remifentanil induces autophagy and prevents hydrogen peroxide-induced apoptosis in Cos-7 cells

  • Yoon, Ji-Young;Baek, Chul-Woo;Woo, Mi-Na;Kim, Eun-Jung;Yoon, Ji-Uk;Park, Chang-Hoon
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.16 no.3
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    • pp.175-184
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    • 2016
  • Background: This study investigated the effect of remifentanil pretreatment on Cos-7 cells exposed to oxidative stress, and the influence of remifentanil on intracellular autophagy and apoptotic cell death. Methods: Cells were divided into 4 groups: (1) Control: non-pretreated cells were incubated in normoxia (5% $CO_2$, 21% $O_2$, and 74% $N_2$). (2) $H_2O_2$: non-pretreated cells were exposed to $H_2O_2$ for 24 h. (3) RPC+$H_2O_2$: cells pretreated with remifentanil were exposed to $H_2O_2$ for 24 h. (4) 3-MA+RPC+$H_2O_2$: cells pretreated with 3-Methyladenine (3-MA) and remifentanil were exposed to $H_2O_2$ for 24 h. We determined the cell viability of each group using an MTT assay. Hoechst staining and FACS analysis of Cos-7 cells were performed to observe the effect of remifentanil on apoptosis. Autophagy activation was determined by fluorescence microscopy, MDC staining, and AO staining. The expression of autophagy-related proteins was observed using western blotting. Results: Remifentanil pretreatment increased the viability of Cos-7 cells exposed to oxidative stress. Hoechst staining and FACS analysis revealed that oxidative stress-dependent apoptosis was suppressed by the pretreatment. Additionally, fluorescence microscopy showed that remifentanil pretreatment led to autophagy-induction in Cos-7 cells, and the expression of autophagy-related proteins was increased in the RPC+$H_2O_2$ group. Conclusions: The study showed that remifentanil pretreatment stimulated autophagy and increased viability in an oxidative stress model of Cos-7 cells. Therefore, we suggest that apoptosis was activated upon oxidative stress, and remifentanil preconditioning increased the survival rate of the cells by activating autophagy.

Astaxanthin Inhibits $H_2O_2$-Mediated Apoptotic Cell Death in Mouse Neural Progenitor Cells via Modulation of P38 and MEK Signaling Pathways

  • Kim, Jeong-Hwan;Choi, Woo-Bong;Lee, Jong-Hwan;Jeon, Sung-Jong;Choi, Yung-Hyun;Kim, Byung-Woo;Chang, Hyo-Ihl;Nam, Soo-Wan
    • Journal of Microbiology and Biotechnology
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    • v.19 no.11
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    • pp.1355-1363
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    • 2009
  • In the present study, the neuroprotective effects of astaxanthin on $H_2O_2$-mediated apoptotic cell death, using cultured mouse neural progenitor cells (mNPCs), were investigated. To cause apoptotic cell death, mNPCs were pretreated with astaxanthin for 8 h and followed by treatment of 0.3 mM $H_2O_2$. Pretreatment of mNPCs with astaxanthin significantly inhibited $H_2O_2$-mediated apoptosis and induced cell growth in a dose-dependent manner. In Western blot analysis, astaxanthin-pretreated cells showed the activation of p-Akt, p-MEK, p-ERK, and Bcl-2, and the reduction of p-P38, p-SAPK/JNK, Bax, p-GSK3b, cytochrome c, caspase-3, and PARP. Because $H_2O_2$ triggers caspases activation, this study examined whether astaxanthin can inhibit caspases activation in $H_2O_2$-treated mNPCs. After $H_2O_2$ treatment, caspases activities were prominently increased, but astaxanthin pretreatment significantly inhibited $H_2O_2$-mediated caspases activation. Astaxanthin pretreatment also significantly recovered the ATP production ability of $H_2O_2$-treated cells. These findings indicate that astaxanthin inhibits $H_2O_2$-mediated apoptotic features in mNPCs. Inhibition assays with SB203580 ($10\;{\mu}M$, a specific inhibitor of p38) and PD98059 ($10\;{\mu}M$, a specific inhibitor of MEK) clearly showed that astaxanthin can inhibit $H_2O_2$-mediated apoptotic death via modulation of p38 and MEK signaling pathways.

Treatment of Landfill Leachate using H2O2/O3 AOP and UASB Process (I) - Treatment Characteristics of Leachate depending on H2O2/O3 AOP Pretreatment and Available Nitrogen Form - (H2O2/O3 AOP와 UASB 공정을 이용한 매립지 침출수 처리(I) - H2O2/O3 AOP 전처리 및 질소원에 따른 침출수별 처리특성 -)

  • Jeong, Seung Hyun;Jeong, Byung Gon
    • Journal of Korean Society on Water Environment
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    • v.21 no.6
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    • pp.643-650
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    • 2005
  • In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.

The Effects of Hydrogen Peroxide Pretreatment on Rice Straw Fermentation for Feed (볏짚 발효사료 제조시 과산화수소 전처리 효과)

  • Choi, Yoon-Hee;Lee, Sang-Bok;Kim, Myeong-Sook;Hong, Jai-Sik
    • Applied Biological Chemistry
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    • v.37 no.5
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    • pp.326-333
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    • 1994
  • Pleurotus florida with high cellulase activity as well as lignin degradability was selected out among strains for fermentation of the rice straw to improve the nutritive value. When the rice straw was fermented by P. florida, the contents of hemicellulose, cellulose and lignin were decreased to 22.5%, 11.4% and 28.1%, respectively, whereas the contents of rice straw fermented after pretreatment with $H_2O_2$ or alkaline hydrogen peroxide were decreased much in the lower concentration. The content of T-N (total-nitrogen) and crude fat was increased with the longer fermentation period. The amino acid content of rice straw fermented by P. florida in 30 days was increased to 28.9% and 35.1% as the rice straw was fermented after pretreatment without and with 4% $H_2O_2$, respectively. The crystalline intensity of rice straw was decreased by pretreatment with 4% $H_2O_2$ and fermentation by P. florida. However, the crystall intensity was increased by treatment with alkaline hydrogen peroxide and the more when the straw was washed after the treatment. When the rice straw was fermented by P. florida for 30 days, the in vitro organic matter digestibility was increased up to 6% of $H_2O_2$ pretreatment.

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A Study on Proper Fenton Oxidation Conditions for Pretreatment of Livestock Wastewater (축산폐수 전처리를 위한 펜톤산화 적정조건에 관한 연구)

  • Kim, Jong Oh;Jeong, Seong Uk
    • Journal of the Korea Organic Resources Recycling Association
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    • v.13 no.4
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    • pp.107-117
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    • 2005
  • The objective of this study was to investigate the proper operation conditions of fenton oxidation such as initial pH, $H_2O_2/Fe^{2+}$ ratio, $H_2O_2/Fe^{2+}$ dosage amount, and neutralizing agent for pretreatment of the livestock wastewater. Fenton oxidation reagents were reacted with the livestock wastewater for 2 hours at 120 rpm and the settling was performed for 2 hours using jar-tester apparatus under the different experimental conditions. And then the supernatant was sampled and measured for the residual $H_2O_2$, $COD_{Cr}$, and SS. The results are as follows; optimum initial pH=4, optimum $H_2O_2/Fe^{2+}$ ratio=10:1, optimum $H_2O_2/Fe^{2+}$ dosage amount=5,000/500 mg/L and $Ca(OH)_2$ as proper neutralizing agent. The removal efficiency of $COD_{Cr}$ and SS were 43% and 84% under those optimal fenton oxidation conditions.

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Immunomodulating Effects on Macrophage of Rhamnan Sulfate Extracted from Monostroma nitidum (홀파래에서 추출한 Rhamnan sulfate의 Macrophage에 의한 면역조절효과에 관한 연구)

  • 류병호;빈재훈;김희숙
    • Journal of Food Hygiene and Safety
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    • v.11 no.4
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    • pp.235-241
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    • 1996
  • The rhamnan sulfate extracted from green algae seaweed, Monostroma nitidum was characterized as activity in vitro culture assay with macrophages from mice. Rhamnan sulfate indicated that F-4-3 fraction enhanced glucose consumption, as well as the production of nitrogen dioxide and tumor necrosis factor(TNF). F-4-3 fraction was also augmented IL-1 secretion from those macrophages. Effects of the pretreatment of peritoneal macrophages with rhamnan sulfate F-4-3 fraction and several polysaccharides as relative standard on the production of H2O2 induced with unopsonized zymosan A were examined. Pretreatment with polysaccharides inhibited the zymosan A mediated H2O2 production by macrophages. The phorbol myristate acetate (PMA) mediated H2O2 production was not affected by the pretreament. These result suggested that pretreatment of rhamnan sulfate interfered with the interaction of macrophages zymosan A. Rhamnan sulfate inhibited zymosan A mediated production of H**O** by macrophages and F-4-3 Fraction was also activator of macrophages.

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Protective Effects of Ukyium(우귀음, Yougui-yin) in Zinc-induced Apoptosis of C6 Glial Cells (우귀음이 Zinc에 의한 신경교세포의 고사(Apoptosis)에 미치는 영향)

  • 이영구;문병순
    • The Journal of Korean Medicine
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    • v.22 no.3
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    • pp.63-73
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    • 2001
  • Objectives : The objective of the current study is to determine the protective effect of Ukyium(Yougui-yin) on the apoptosis induced by zinc. Methods : Zinc is known to generate reactive oxygen species (ROS), including superoxide anion ($O_2$) and hydrogen peroxide ($H_2O_2$), which eventually contribute to cytotoxicity in a variety of cell types. We investigated the viablity of cells, $H_2O_2$ generation, chromatin condensation and nuclear fragmentation in Hoechst dye staining and $IkB-{\alpha}$ degradation in C6 glial cells of $ZnCl_2$ between pretreatment- and not pretreatment-group with Ukyium. The former methods were researched by Time- and Dose-dependent manners. Results : We demonstrated that pretreatment with Ukyium prevented zinc-induced cell death of C6 glial cells and apoptotic characteristics including chromatin condensation and nuclear fragmentation. Ukyium also prevented $H_2O_2-induced$ cell death. We further confirmed that Ukyium decreased zinc-induced generation of $H_2O_2$ and inhibited degradation of $IkB-{\alpha}$ by zinc in C6 glial ceHs. Conclusions : These data indicated that Ukyium (Yougui-yin) prevents zinc-induced apoptotic death of C6 glial cells via inhibition of ROS generation, such as $H_2O_2$ as well as inhibition of $IkB-{\alpha}$ degradation.

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Pretreatment with Lycopene Attenuates Oxidative Stress-Induced Apoptosis in Human Mesenchymal Stem Cells

  • Kim, Ji Yong;Lee, Jai-Sung;Han, Yong-Seok;Lee, Jun Hee;Bae, Inhyu;Yoon, Yeo Min;Kwon, Sang Mo;Lee, Sang Hun
    • Biomolecules & Therapeutics
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    • v.23 no.6
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    • pp.517-524
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    • 2015
  • Human mesenchymal stem cells (MSCs) have been used in cell-based therapy to promote revascularization after peripheral or myocardial ischemia. High levels of reactive oxygen species (ROS) are involved in the senescence and apoptosis of MSCs, causing defective neovascularization. Here, we examined the effect of the natural antioxidant lycopene on oxidative stress-induced apoptosis in MSCs. Although $H_2O_2$ ($200{\mu}M$) increased intracellular ROS levels in human MSCs, lycopene ($10{\mu}M$) pretreatment suppressed $H_2O_2$-induced ROS generation and increased survival. $H_2O_2$-induced ROS increased the levels of phosphorylated p38 mitogen activated protein kinase (MAPK), Jun-N-terminal kinase (JNK), ataxia telangiectasia mutated (ATM), and p53, which were inhibited by lycopene pretreatment. Furthermore, lycopene pretreatment decreased the expression of cleaved poly (ADP ribose) polymerase-1 (PARP-1) and caspase-3 and increased the expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax), which were induced by $H_2O_2$ treatment. Moreover, lycopene significantly increased manganese superoxide dismutase (MnSOD) expression and decreased cellular ROS levels via the PI3K-Akt pathway. Our findings show that lycopene pretreatment prevents ischemic injury by suppressing apoptosis-associated signal pathway and enhancing anti-oxidant protein, suggesting that lycopene could be developed as a beneficial broad-spectrum agent for the successful MSC transplantation in ischemic diseases.