• 멤브레인
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• 제24권5호
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• pp.367-374
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• 2014

본 연구에서는 LSCF/GDC (20 : 80 vol%) 복합 분리막 표면에 LSC/GDC (50 : 50 vol%) 활성층을 코팅한 후 활성층의 열처리 온도, 두께, 침투법을 이용한 STF 도입이 산소투과 특성에 미치는 영향을 고찰하였다. 활성층 도입은 복합 분리막의 산소 투과 유속을 급격히 증진시켰으며 이는 활성층 성분인 LSC/GDC (50 : 50 vol%)가 전자 전도성 및 표면 산소 분해 반응을 증진시켰기 때문이었다. 활성층의 열처리 온도가 $900^{\circ}C$에서 $1000^{\circ}C$로 증가한 경우, 산소 투과 유속은 증가하였고 이는 분리막과 활성층 사이 그리고 활성층의 결정입간 접촉이 증진하여 산소이온과 전자 흐름을 증진시켰기 때문으로 설명되었다. 코팅층의 두께가 약 $10{\mu}m$에서 약 $20{\mu}m$로 증가한 경우, 산소 투과 유속은 오히려 감소하였는데 이는 코팅층의 두께가 증가할수록 기공을 통한 공기 중의 산소 유입이 어려워지기 때문으로 설명되었다. 또한, 코팅층에 침투법을 이용하여 STF를 도입한 경우가 STF를 도입하지 않은 경우 보다 높은 산소 투과 유속을 보였는데 이는 도입된 STF가 산소 분해하는 표면 반응 속도를 촉진시키기 때문이다. 본 연구로부터 LSC/GDC (50 : 50 vol%) 활성층 코팅 및 특성 제어는 LSCF/GDC (20 : 80 vol%) 복합 분리막의 산소투과 증진에 매우 중요함을 확인하였다.

• Food Science and Biotechnology
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• 제18권1호
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• pp.73-78
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• 2009

Processed meatball products were packaged in a passive package without oxygen scavenger as 1 control and 3 active packages of which have PP-based oxygen scavenger master batch materials (OSMB) of 40, 80, and 100%(w/w) in the middle layer and stored at 23 and $30^{\circ}C$ up to 9 months. Quality changes of packaged products were evaluated by measuring the oxygen concentration of the headspace in containers, thiobarbituric acid (TBA), color, and flavor. The oxygen concentration of the package having 100% OSMB was lower than those of 40 and 80%. The color changes and TBA values of the meat ball in the package containing 100% OSMB were the least among the treatments. Using principal component analysis (PCA), the control showed more flavor change than the packages containing oxygen scavenger. As a result, all active packages could extend the shelf life of the meatball products compared with that of the passive package.

• 한방안이비인후피부과학회지
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• 제22권2호
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• pp.74-81
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• 2009

Background and Objective : There are a lot of theories that explained the aging process, and the oxidative stress is one of the important theory that explained the aging process. The aim of this study was to investigate active oxygen and antioxidant capacity of Qi deficiency and Blood deficiency animal models. Material and Methods : Sprague-Dawley rats were divided into three groups: normal group, Qi deficiency group and Blood deficiency group. The Qi deficiency animal model was induced through restriction of food (12g/kg/day) for 20 days. Blood deficiency animal model was induced by bleeding from tail vein(0.4ml/time) 8 times. The normal animal model was kept without any intervention. The oxidative stress was observed by measuring the active oxygen and antioxidant capacity. Results and Conclusion : 1. Active oxygen was significantly increased in the Qi deficiency group and Blood deficiency group. (P=0.061) 2. Antioxidant capacity was increased in the Qi deficiency group and Blood deficiency group. But there is no significant difference. (P=0.113)

• Journal of Ginseng Research
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• 제13권1호
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• pp.98-104
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• 1989

In order to determine the specific active oxygen species directly related to chlorophyll bleaching in the leaf-burning disease, we investigated the effects of singlet oxygen (1O2), superoxide radical (O2-), and hydrogen Peroxide (H2O2) on isolated chloroplast suspension and leaf discs from Panax ginseng C.A. Meyer. When the singlet oxygen was added to the chloroplast suspension, the chlorophyll and carotenoid contents were decreased by more than 809), similar to treatment with high light intensity (100 KLux). We assumed that the conversion of dioxygen (O2) produced either in photolysis or in breakdown of hydrogen peroxide to singlet oxygen resulted from photorespiration. On the basis of these experiments , :he inhibitory effects of active oxygen scavengers propylgallic acid (PGA), 2,5-ditetrabutyl hydroquinon (DBH), sodium pyrosulfate (SPS), and ascorbic acid (ABS) were examined. In chloroplast suspension all four scavengers inhibited chlorophyll bleaching by more than 75fl , and in the leaf discs the inhibition rates of SPS, PGA and ABS were 46%, 51%, and 96% respectively.

• Bulletin of the Korean Chemical Society
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• 제16권5호
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• pp.392-397
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• 1995

o-Phenylenediamine (o-PD) was electropolymerized on glassy carbon electrodes under a potential cycling condition. The resulting polymer films mediated electrons for the reduction of molecular oxygen at pH=1.0. It was found from the RDE, RRDE, and cyclic voltammetry experiments that the modified electrodes reduce oxygen to hydrogen peroxide at about 300 mV lower potential than the bare glassy carbon electrode. The polymer film consisted of more than two components. Among those, only one component was active in oxygen reduction, which was formed mainly in the earlier stage of the electropolymerization. 2,3-Diaminophenazine, a cyclic dimer of o-PD, was also active in the oxygen reduction reaction, from which it was suggested that the active polymeric component has a structural unit similar to the cyclic dimer. Finally, the electropolymerization mechanism for the formation of the active and inactive components has been proposed.

• 한국식품영양과학회지
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• 제29권1호
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• pp.106-110
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• 2000

We investigated the active oxygen scavenging activity and active compound from Humulus japonicus. The ethyl acetate and butanol fraction exhibited strong scavenging effects on hydroxyl radical. Furthermore active compound was isolated and purified using Amberlite XAD-2 column chromatography and preparative HPLC from ethyl acetate fracton, and major compound was identified as a luteolin-7-O-$\beta$-D-glucoside by the MS, UV, 1H-NMR and 13C-NMR analyses. Luteolin-7-O-$\beta$-D-glucoside exhibited strong scavenging effect on active oxygens such as superoxide radical, hydroxyl radical and hydrogen peroxide.

• 스마트미디어저널
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• 제1권4호
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• pp.52-58
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• 2012

최근 고령화에 따른 사회적인 문제를 해결하기 위한 대안으로 IT와 BT기술을 접목한 U헬스 의료서비스가 주목을 받고 있다. 활성산소는 체내의 불안정한 상태의 유해산소로서 노화의 주원인이 되고, 다른 질병을 유발할 위험성이 크며, 현대인의 질병 중 약 905가 활성산소와 관련이 있다. 따라서 고 연령층과 지병환자들 뿐만 아니라 일반일들도 활성산소 포화도를 체계적으로 관리해야 할 필요성이 있다. 본 논문에서 신체로부터 측정한 활성산소 측정데이터를 의료기관의 데이터 저장소로 전송하여 서비스 제공자로부터 진단을 받을 수 있는 효과적인 U헬스 시스템에 대하여 소개한다. 제안하는 시스템은 사용자의 신체검사정보확인, 의료기기와 모바일 간의 표준에 따른 블루투스 데이터 통신, 의료정보 기능을 지원하고, 또한 모바일의 3G/4G, Wi-Fi를 이용하여 게이트웨이 역할을 수행하도록 설계하였다. 제안시스템의 U헬스 기기와 모바일 간의 표준에 의한 데이터통신을 통해 의료기관으로부터 언제, 어디서든 진단을 받을 수 있는 효과적인 U헬스 서비스 환경을 구축할 수 있다.

• 약학회지
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• 제37권6호
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• pp.647-658
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• 1993

The susceptibilities of aldehyde dehydrogenase (AldDH) and alcohol dehydrogenase (ADH) to active oxygen generated by xanthine-xanthine oxidase (XOD) system were studied. Incubation of AldDH with 2$\times$10$^{-3}$ units of XOD for 30 min at $25^{\circ}C$ resulted in the decrease of enzyme activity to 30% and it was inactivated completely when incubated with 5$\times$10$^{-3}$ units of XOD. Whereas 70% of ADH activity was retained after exposure to 5$\times$10$^{-3}$ units of XOD for 30 min, 40% of ADH activity was retained after exposure to 5$\times$10$^{-2}$ unit of XOD for 30 min. This inhibition effect by the active oxygen was preventable by catalase and glutathione, but not by SOD. The rates of the NADPH-dependent oxygen consumption by the liver S-9 mixture and microsomes were also determined in this study. Rate of oxygen consumption is increased in the liver S-9 mix and microsomes from phenobarbital-treated rat, and it was consistent with increased lipid peroxidation. In the presense of ethanol as a substrate, the oxygen consumption rates were increased. It is reported that hepatic AldDH activity is depressed in alcoholic liver diseases, however there is few report that explains the reason of depressed AldDH activity. These results are supportive of the theory that the increase in hepatic ethanol oxidation through the induced ME activity after chronic ethanol feeding generate oxygen radical at elevated rates and it leads to the depression of AldDH activity.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.169-182
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• 2017

Iron and nitrogen codoped carbon (Fe-N/C) catalysts have emerged as one of the most promising replacements for state-of-the-art platinum-based electrocatalysts for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells. During the last decade, significant progress has been achieved in Fe-N/C catalysts in terms of ORR activity improvement and active site identification. In this review, we focus on recent efforts towards advancing our understanding of the structure of active sites in Fe-N/C catalysts. We summarize the spectroscopic and electrochemical methods that are used to analyze active site structure in Fe-N/C catalysts, and the relationship between active site structure and ORR activity in these catalysts. We provide an overview of recently reported synthetic strategies that can generate active sites in Fe-N/C catalysts preferentially. We then discuss newly suggested active sites in Fe-N/C catalysts. Finally, we conclude this review with a brief future outlook.

• 한국포장학회지
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• 제30권1호
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• pp.43-51
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• 2024

The addition of oxygen scavengers to food products helps to reduce oxygen exposure, thereby mitigating deterioration, including changes in taste, odor, and color, as well as inhibiting microbial growth. Despite the advantages of the existing non-metallic oxygen removal materials in terms of safety for the human body and suitability for use in microwave ovens, their utilization has been limited due to their slow reaction initiation speed. Therefore, in the current study, sodium metabisulfite was impregnated into various porous media, including halloysite nanoclay, activated carbon, montmorillonite, and silica gel. The oxygen scavenger, produced by impregnating silica gel with sodium metabisulfite, demonstrated a 425% improvement in the initial oxygen removal rate compared to pure sodium metabisulfite. Additionally, sachets containing an oxygen-removing composition with an enhanced oxygen removal rate effectively decreased the oxygen concentration to less than 0.5% on the third day of storage in apple packaging, without elevating carbon dioxide levels. Moreover, it proved effective in preventing the browning of the apple surface. Therefore, the SM/SG oxygen-removal composition can be effectively applied to active food packaging by controlling the oxygen concentration within the packaging.