• Title/Summary/Keyword: oxidation time

Search Result 1,543, Processing Time 0.028 seconds

Effects of Samkieum on LDL Oxidation in Macrophage Cell (지단백산화(脂蛋白酸化)에 따른 대식세포(大食細胞) 활성(活性)에 미치는 삼기음(三氣飮)의 영향(影響))

  • Lee, Hee-Jo;Hwang, Gwi-Seo;Kim, Kyung-Jun
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
    • /
    • v.19 no.2
    • /
    • pp.108-117
    • /
    • 2006
  • The oxidative notification of low density lipoprotein(LDL) has been implicated in the development of atherosclerosis. Oxidized LDL are found in macrophage foam cell, and it can induce an macrophage proliferation in atherosclerotic plaque. In this study, we investigated the hypothesis that Samkieum may reduce atherosclerosis by lowering the oxidiazability of LDL, To achieve this goal, we examined the effect of Samkieum on LDL oxidation nitric oxide production in mouse macrophage cell line, RAW264.7, and the effect of Samkieum on cupuric sulfate-induced cytotoxicity, LDH release, and macrophage activity. Samkieum inhibited the generation of oxidized LDL from native LDL in RAW264.7 cell culture, and decreased the release of LDH from cupric sulfate-stimulated RAW264.7 cell. In other experiments, Samkieum activated RAW264.7 cell, and prolonged the survival time, and increased nitric oxide production in Raw 264.7 cells.

  • PDF

A Study of fixed oxide charge in thin flim MOS structure (박막 MOS 구조의 고정표면전하에 관한 연구)

  • Yu, Seok-Bin;Kim, Sang-Yong;Seo, Yong-Jin;Chang, Eui-Goo
    • Proceedings of the KIEE Conference
    • /
    • 1989.07a
    • /
    • pp.377-379
    • /
    • 1989
  • Very thin gate oxide(100-300A) MOS capacitor has been fabricated. The effect of series resistance must be calculated and the exact metal-semiconductor work function difference should be obtained to get the fixed oxide charge density exisiting in oxide. Dilute oxidation make sagy to control oxide thickness and reduce fixed oxide charge density. In case of dilute oxidation, fixed oxide charge density depends on oxidation time. If oxide is very thin, the annealing effect is ignored.

  • PDF

Growth mechanism of anodic oxide for MCT passivation (MCT 표면보호를 위한 양극산화막 성장)

  • 정진원;왕진석
    • Electrical & Electronic Materials
    • /
    • v.8 no.3
    • /
    • pp.352-356
    • /
    • 1995
  • Native oxide layer on MCT (HgCdTe) has been grown uniformly in H$\_$2/O$\_$2/ electrolyte through anodic oxidation method. It has been determined that anodic oxidation of HgCdTe in H$\_$2/O$\_$2/ electrolyte proceeds immediately with the input of constant currents without any induction time required for anodic oxideation in KOH electrolyte. Oxide layer with the resistivity of 2*10$\^$10/.ohm.cm and the refractive index of 2.1 suggested the possibility of well matching combination layer with ZnS for MCT MIS device. XPS results indicated that the major components of oxide layer grown in H202 solution is TeO$\_$2/ with the possibility of small amounts of CdTeO$\_$3/.

  • PDF

Modification and Inactivation of Human Ceruloplasmin by Oxidized DOPA

  • Kang, Jung-Hoon
    • Bulletin of the Korean Chemical Society
    • /
    • v.25 no.5
    • /
    • pp.625-628
    • /
    • 2004
  • Ceruloplasmin (CP), the blue oxidase present in all vertebrates, is the major copper-containing protein of plasma. It has been proposed that oxidation of L-3,4-dihydroxyphenylalanine (DOPA) may contribute to the pathogenesis of neurodegenerative disorders. The effect of the oxidized products of DOPA on the modification of human CP was investigated. When CP was incubated with the oxidized L-DOPA, the protein was induced to be aggregated and ferroxidase activity was decreased in a time-dependent manner. Radical scavengers and catalase significantly inhibited the oxidized DOPA-mediated CP aggregation. Copper chelatrors, Diethylenetriaminepenta acetic acid (DTPA) and Diethyldithiocarbamic acid (DDC), also inhibited the oxidative modification of CP. The results suggested that DOPA oxidation led to the formation of free radical and induced the CP aggregation.

Effect of Cooling Rate on the Behavior of the Embrittlement in Zircaloy-4 Cladding (냉각속도가 지르칼로이-4 피복관의 취성에 미치는 영향)

  • Kim, Jun Hwan;Lee, Myoung Ho;Choi, Byoung Kwon;Jeong, Yong Hwan
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.18 no.2
    • /
    • pp.112-118
    • /
    • 2005
  • Study was focused on the effect of the cooling rate on the embrittlement behavior of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment. Claddings were oxidized at given temperature and given time followed by various water quenching in the range of $0.6^{\circ}C$ and $100^{\circ}C$ per second. Cladding failed after water quenching above the threshold oxidation. Threshold oxidation was decreased as the cooling rate increased, which is due to the matensite structure formed during fast cooling rate.

Degradation of THM precursor using $TiO_2$ photocatalytic oxidation in the water treatment processes (정수처리공정에서 $TiO_2$광촉매를 이용한 THM전구물질 제거에 관한 연구)

  • Cho Deok-Hee;Seo Su-Man
    • Journal of environmental and Sanitary engineering
    • /
    • v.19 no.2
    • /
    • pp.1-6
    • /
    • 2004
  • In Bok-Jeong water treatment plant, chlorination is the only technique used for disinfection of drinking water. This disinfecting treatment leads to the formation of trihalomethanes (THMs). This study was carried out to investigate the possibility of improving removal efficiency of THM precursor in the conventional water treatment processes by $TiO_2$ photocatalytic oxidation. Removal efficiencies of DOC, $UV_{254}$, THMFP were low in the conventional water treatment processes. With application of $TiO_2$ photocatalyst, DOC, $UV_{254}$, THMFP were reduced more effectively. As the $TiO_2$ photocatalytic reaction time increased, the removal efficiencies of DOC, $UV_{254}$, THMFP were increased. The $TiO_2$ photocatalytic removal efficiencies of DOC, $UV_{254}$, THMFP were increased with increasing $TiO_2$ dosage. However, over 0.6g/l of $TiO_2$ dosage, the efficiency reached a plateau.

Electrical Conductivity of Polymeric Composites with respect to Damage of Carbon Nanotube (탄소나노튜브의 손상에 따른 전기전도도 변화)

  • Kim Yun Jin;Jeong Yeon Chun;Yun Ho Gyu
    • Proceedings of the International Microelectronics And Packaging Society Conference
    • /
    • 2003.11a
    • /
    • pp.22-26
    • /
    • 2003
  • Electrical conductivity of the oxidized MWNT(Multi walled nanotubes)/polymer composites were investigated with respect to various oxidative conditions of acid concentration, treatment temperature, and treatment time. To remove the impurities existing in MWNT-deposites, liquid-phase oxidation was performed using the $HNO_3/HSO_4$ mixtures. Secondary effects occurred by the oxidation of MWNTs such as the damages of MWNTs and the introduction of functionalities were analyzed through measuring FT-IR, TEM, and zeta potential, All the oxidized NWNTs were functionalized with carboxylic groups and the conditions of oxidation of the MWNTs could have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT. The electrical properties of MWNT composites strongly depend on the oxidative conditions of MWNTs. The conductivity of the composites filled with the proper oxidized MWNT showed the highest percolation threshold.

  • PDF

Development of finite element numerical simulation for three-dimensional oxidation (3차원 산화 공정을 위한 유한요소법 수치 해석기 개발에 관한 연구)

  • 이제희;윤상호;송재복;김윤태;원태영
    • Journal of the Korean Institute of Telematics and Electronics D
    • /
    • v.34D no.3
    • /
    • pp.74-86
    • /
    • 1997
  • With continued miniaturization and development of new devices, the highly nonuniform oxidation of three-dimensional non-planar silicon structures plays an increasingly important role. In this paper, the three-dimensional finite element numerical simulator. Grwoth of oxide is a coupled process of diffusion of oxidant and deformation of oxide. Because boundaries of oxide are moved in each time step and LOCOS structure is formed three-dimensional shape of sruface, it is necessary to develope an efficient node control algorithm that can locally generate and eliminate the node. Therefore we have developed the optimized three-dimensional mesh generator which is cpable of refining and eliminating the meshes at the moving boundary of oxide, and hve developed three-dimensional finite element oxidation solver.

  • PDF

Effects of Basil and Majoram Essential Oils with or without Ascorbic Acid on Color and Oxidative and Microbial Stability of Beef Patties

  • Chung, Hai-Jung
    • Preventive Nutrition and Food Science
    • /
    • v.9 no.1
    • /
    • pp.1-6
    • /
    • 2004
  • Fresh ground beef was mixed with ascorbic acid, basil essential oil, majoram essential oil, or each essential oil combined with ascorbic acid and stored at 1 $\pm$ 1$^{\circ}C$ for 7 days. Color, lipid oxidation (TBARS formation), aerobic bacterial counts and pH were determined. Basil and majoram essential oils were effective in inhibiting color deterioration, lipid oxidation and bacterial growth. The combined addition of basil and ascorbic acid showed the highest protection against color fading, followed by majoram + ascorbic acid, and ascorbic acid alone. Basil and majoram essential oils were most effective in delaying TBARS formation (p < ().01). Ascorbic acid did not exert an antioxidative effect and even exhibited a pro-oxidant effect. The pH values of all samples increased slightly, but no significant differences were observed, either among treatments or throughout the storage time (p > 0.05).

Optimizing Oily Wastewater Treatment Via Wet Peroxide Oxidation Using Response Surface Methodology

  • Shi, Jianzhong;Wang, Xiuqing;Wang, Xiaoyin
    • Journal of the Korean Chemical Society
    • /
    • v.58 no.1
    • /
    • pp.80-84
    • /
    • 2014
  • The process of petroleum involves in a large amount of oily wastewater that contains high levels of chemical oxygen demand (COD) and toxic compounds. So they must be treated before their discharge into the receptor medium. In this paper, wet peroxide oxidation (WPO) was adopted to treat the oily wastewater. Central composite design, an experimental design for response surface methodology (RSM), was used to create a set of 31 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the COD removals. The experimental results show that WPO could effectively reduce COD by 96.8% at the optimum conditions of temperature $290^{\circ}C$, $H_2O_2$ excess (HE) 0.8, the initial concentration of oily wastewater 3855 mg/L and reaction time 9 min. RSM could be effectively adopted to optimize the operating multifactors in complex WPO process.