• 제목/요약/키워드: oxygen effect

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Adsorption of Oxygen and Segregation of Impurity on Copper Surface(polycrystal): An AES Study (다결정 구리 표면에서 산소 흡착과 불순물 표면적출 : AES에 의한 연구)

  • Byoung Sung Han
    • Journal of the Korean Institute of Telematics and Electronics
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    • 제25권8호
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    • pp.966-971
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    • 1988
  • AES was used to study oxygen adsorption due to the oxygen exposure at 300\ulcorner temperature and segregation of impurities due to annealing on polycrystal copper surface. The intensity of peak of CuM2, 3VV and CuL3 VV increased with annealing time and the peak of CKLL increased after Ar ion bombardment. The effect of oxygen adsorption on copper surface at 300\ulcorner was verified by the decreased of peak of CuM2, 3VV and CuL3 VV as oxygen exposure increase. The binding energy of copper atoms gradualy shifts from 0.7eV to 1.5eV of copper atoms gradually shifts from 0.7eV to 1.5eV after a oxygen exposure. After the oxygen exposure, the width at half the height of CuM2, 3VV is larger 2V*C/S by the effect of chemical liaison of the copper aton with oxygen atom.

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Effect of Oxygen Pressure on the Morphology of ZnO Nanostructures Fabricated by Thermal Evaporation Technique (열 증발법에 의하여 제작된 ZnO 나노 구조의 형상에 미치는 산소 압력의 영향)

  • Lee, Jung-Hun;Lee, Geun-Hyoung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제25권11호
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    • pp.873-877
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    • 2012
  • The effect of oxygen pressure in the synthesis of ZnO nanostructures through thermal evaporation of Zn powder was investigated. The thermal evaporation process was carried out in oxygen ambient for 1 hr at $1,000^{\circ}C$ under different pressures. The oxygen pressure was changed in range of 0.5 ~ 900 Torr. Any nanostructure was not formed on the specimens prepared at oxygen pressures lower than 10 Torr. When oxygen pressure was 100 Torr, ZnO nanowires were observed. With increasing the oxygen pressure to 500 Torr, the morphology of ZnO nanostructures changed from wire to tetrapod. For all the samples, room temperature photoluminescence spectra show a strong green emission peak at around 550 nm.

Effect of Antioxidant of Citri Reticulatae Pericarpium on Cytotoxicity of Oxygen Free Radicals in Cultured NIH3T3 Fibroblast (배양섬유모세포에서 산소유리기의 세포독성에 대한 진피의 항산화효과에 관한 연구)

  • Oh, Yong-Leol
    • The Korea Journal of Herbology
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    • 제21권4호
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    • pp.143-148
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    • 2006
  • Objectives : It is demonstrated that oxygen free radicals have cytotoxic effect on NIH3T3 fibroblast cells. Recently, many of herb extracts have an effect of antioxidant in oxygen free radical-induced cytotoxicity. But, the toxic mechanism of oxygen free radical is left unknown. The purpose of this study was to examine the cytotoxicity of hydrogen peroxide ($H_2O_2$) and antioxidant effect of Citri reticulatae pericarpium (CRP) on NIH3T3 fibroblasts. Methods : The cytotoxicy was measured by cell viability by XTT assay in NIH3T3 fibroblasts. XTT assay is regarded as a very sensitive screening method for the determination of the cell viability on various chemicals. Results : In this study, H2O2 decreased cell viability according to the dose- and time dependent manners after NIH3T3 fibroblasts were treated with various concentrations of H2O2 for 4 hours. And also, CRP showed the effect of antioxidant on $H_2O_2-induced $ cytotoxicity in cultured NIH3T3 fibroblasts. Conclusion : These results suggest that $H_2O_2$ has highly cytotoxic effect on cultured NIH3T3 fibroblasts by the decrease of cell viavility, and the herb extract such as CRP was showed the effect of antioxidant on $H_2O_2-induced$ cytotoxicity in these cultures.

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The Effect of Co-culture and Oxygen Concentration on In Virto Fertilization of Follicular Oocytes in Korean Native Cattle (공배양 및 산소농도가 한우 난포란의 체외발생에 미치는 영향)

  • 이재관;윤준진;황성수;윤종택;김창근;정영채
    • Korean Journal of Animal Reproduction
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    • 제22권1호
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    • pp.43-50
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    • 1998
  • The effect of oxygen tension on embryonic development in co-culture was evaluated from the standpoint of the reduction of dissolved oxygen concentration by the oxygen consumption of feeder cells. Three co-culture systems using bovine oviductal epitherial cells (BOEC), African green monkey kidney cells (Vero cells) or buffalo rat liver cells (BRLC) have been compared in terms of development of bovine embryos derived from oocytes matured and fertilized in vitro. Among the co-cultured embryo, Vero cells su, pp.rted the highest developmental rate (29%) and the other two showed the similar rates. When the co-cultures were incubated in three different oxygen tension such as 5, 10, 20% oxygen atmosphere, embryos co-cultured with Vero cells at 10%-O2 resulted in the highest percentage of development. From the measurement of oxygen consumption of feeder cells, BRLC consumed 1.38 10-10 mg-O2/min/cell which was higher than 0.94 10-10 and 0.26 10-10mg-O2/min/cell for Vero cells and BOEC, respectively. Based on the oxygen consumption data, the phenomena of optimum oxygen tension required in embryo development in vitro has been analyzed, and we suggested that gas phase oxygen concentration, oxygen consumption rate of feeder cells and the number of feeder cells should be considered for the design of optimal co-culture system for effective fertilization of embryos in vitro.

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Effect of Partial Oxygen Pressure on the Growth and Defense Enzyme Activities of Streptomyces coelicolor in continuous culture system (Streptomyces coelicolor의 연속 배양시 산소 분압에 따른 방어 효소의 활성 변화)

  • 박용두;이계준;노정혜
    • Microbiology and Biotechnology Letters
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    • 제22권5호
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    • pp.538-543
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    • 1994
  • Effect of partial oxygen pressure on the cell growth and the activities of oxidative defense enzymes were measured in the continuous culture of Streptomyces coelicolor. Both the wild type and the mutant strain resistant to hydrogen peroxide were cultured and the dry cell weight of the two cultures were measured at different oxygen tensions. Growth of the wild type was inhibited by oxygen at above 0.5 vvm. Growth of the hydrogen peroxide resistant mutant was stimulated by pure oxygen at 0.5 vvm but was inhibited by oxygen at 1.0 vvm. Therefore, growth of the hydrogen peroxide resistant mutant was less affected by the deleterious oxidative stress of oxygen. Activities of the several defense enzymes were also measured at different oxygen tensions. Activities of catalase and glucose-6-phosphate dehydrogenase increased significantly as oxygen pressure increased in the wild type culture. In the mutant, however, increase in those enzyme activities was not obvious whereas the uninduced levels of the above enzymes were higher than those of wild type. As judged by Western blotting, the amount of the major catalase increased as the oxygen pressure increased. This indicates that the induction of the catalase activity by oxygen pressure is mostly due to the increase in the expression level for the major catalase.

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Effect of Bradykinin on Oxygen Consumption in the Distal Tubule and Cortical Collecting Tubule of Rat (흰쥐 원위세뇨관과 피질집합관의 산소소비량에 대한 Bradykinin의 영향)

  • Lee, Seok-Yong;Cho, Kyu-Chul
    • The Korean Journal of Pharmacology
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    • 제26권2호
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    • pp.161-166
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    • 1990
  • Infusion of bradykinin (BK) into the renal arteries increases sodium excretion. However, it is not clear whether natriuresis results from the renal hemodynamic effects or from the direct effect on renal tubular sodium transport. Therefore, we examined the effects of BK on the transport-dependent oxygen consumption in the distal tubule (DT) and cortical collecting tubule (CCT) of deoxycorticosterone-treated rats. BK inhibited oxygen consumption in a dose-dependent way with a maximal reduction at $0.1\;{\mu}M$ BK. The inhibitory effect of BK was not present in the absence of sodium or in the presence of ouabain (1 mM). These data imply that the inhibitory effect of BK is restricted to the sodium transport-dependent oxygen consumption. We also investigated the relationship between the effect of BK on oxygen consumption and arachidonic acid metabolism. Mepacrine $(10\;{\mu}M)$, an inhibitor of membrane phospholipases, prevented the inhibitory effect of BK, but indomethacin (0.5 mM) didn't. These results suggest that BK decreases the sodium transport-related oxygen consumption in the rat DT and/or CCT, and that it may be mediated by products of enzymes other than cyclooxygenase.

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DOPING EFFICIENCIES OF OXYGEN VACANCY AND SN DONOR FOR ITO AND InO THIN FILMS

  • Chihara, Koji;Honda, Shin-ichi;Watamori, Michio;Oura, Kenjiro
    • Journal of Surface Science and Engineering
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    • 제29권6호
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    • pp.876-879
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    • 1996
  • The effect of oxygen vacancy and Sn donor on carrier density for Indium Tin oxide (ITO) and Indium oxide (InO) films has been investigated. Hot-cathode Penning discharge sputtering (HC-PDS) in the mixed gasses of argon and oxygen was applied to fabricate the ITO and InO films. Density of oxygen vacancy was estimated using a high-energy ion beam technique. The electrical properties of the films such as resistivity, carrier density and mobility were estimated by Van der Pauw method. The doping efficiency of oxygen vacancy could be obtained from the relationship between oxygen vacancy and carrier density. The doping efficiency of oxygen vacancy for ITO films resulted in a quite small value. Comparing the doping efficiencies of ITO and InO films, the effect of Sn donor on carrier density was also discussed.

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Effect Oxygen in Inflation Gas for Warm Ischemia-reperfusion Injury in the Lung of a Mongrel Dog (황견에서 폐장의 산소가 온열 허혈후 재관류 시폐손상에 미치는 영향)

  • 성숙환;김현조;김영태
    • Journal of Chest Surgery
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    • 제33권2호
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    • pp.125-131
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    • 2000
  • Background: Hyperinflation during lung ischemia has been known to improve pulmonary functions after reperfusion which may be exerted through a pulmonary vasodilation and avoidance of atelectasis by an increased surfactant release and been known whether the improvement of pulmonary function was the effect of hyperinflation itself or the oxygen content in inflation gas. Therefore we attempted to clarify the effect of hyperinflation with oxygen in pulmonary inflation gas during warm ischemia on pulmonary function after reperfusion to solve the problem of ischemia-reperfusion injury after lung transplantation. Material and Method: sixteen mongrel dogs were randomly divided into two groups: the left lung was inflated to 30-35 cm H2O with 100% oxygen in oxygen group and 100% nitrogen in nitrogen group. The inflated left lung was maintained with warm ischemia for 100 minutes. Arterial and mixed venous blood gas analysis and hemodynamics were measured before ischemia and 30, 60, 120, 180 and 240 minutes afer reperfusion. Lung biopsy was taken for the measurement of lung water content after the end of reperfusion. Result: In oxygen group arterial oxygen tension the difference of arterial and mixed venous oxygen tension and the difference of alveolar-arterial oxygen tension at 30-minute after reperfusion were not significantly different from those before ischemia and were stable during the 40hour reperfusion. However in nitrogen group these values were significantly deteriorated at 30-minute after reperfusion. there was no significant difference between two groups in hemodynamic data peak airway pressure and lung water content. Conclusion : The results indicated that the oxygenation one of the most important pulmonary functions was improved by pulmonary inflation with 100% oxygen during warm ischemia but the hemodynamics were not. Oxygen as a metabolic substrate during warm ischenia was believed to make the pulmonary tissues to maintain aerobic metabolism and to prevent ischemic damage of alveoli and pulmonary capillary.

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The Effect of Highly Concentrated Oxygen Administration on Cerebrum Lateralization of Young Men during Visuospatial Task (고농도의 산소 공급이 공간지각 과제 수행 시 젊은 성인 남자의 대뇌 편측화에 미치는 영향)

  • 정순철;손진훈;김익현
    • Journal of the Korean Society for Precision Engineering
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    • 제21권8호
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    • pp.180-187
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    • 2004
  • The present study attempted to investigate the effects of supply of highly concentrated (30%) oxygen on human ability of visuospatial cognition and cerebrum lateralization. compared to air of normal oxygen concentration (21%). The experiment consisted of two runs, one fur visuospatial cognition test with normal air (21% of oxygen) and for visuospatial cognition test with more oxygen in the air (30% of oxygen). Each run was composed of four blocks and each block included eight control tasks and five visuospatial tasks. Functional brain images were taken from 3T MRI using the single-shot EPI method. The result of task performance showed the accuracy increased at 30%'s concentration of oxygen rather than 21%'s. There were more activations observed at the left and right hemisphere, but there was decrease cerebrum lateralization with 30% oxygen administration. Thus, it is concluded that the positive effect on the visuospatial cognitive performance level by the highly concentrated oxygen administration was due to increase of cerebrum activation and decrease of cerebrum lateralization

Effect of Oxygen Pressure in the Synthesis of ZnO Nanowires through Melt Oxidation of Al-Zn Mixture (Al-Zn 혼합물을 용융 산화시켜 생성되는 ZnO 나노선의 성장에 미치는 산소압력의 영향)

  • Lee, Geun-Hyoung
    • Korean Journal of Materials Research
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    • 제24권6호
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    • pp.301-304
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    • 2014
  • The effect of oxygen pressure on the synthesis of ZnO nanowires by means of melt-oxidation of an Al-Zn mixture was investigated. The samples were prepared in oxygen ambient for 1 h at $1,000^{\circ}C$ under oxygen pressure ranging from 0.5 to 100 Torr. ZnO nanowires were formed at oxygen pressures lower than 10 Torr. As the oxygen pressure increased from 0.5 to 10 Torr, the width of the nanowires increased, but their length decreased. The ZnO nanowires had a needle shape, which became gradually thinner toward the tip. X-ray diffraction patterns showed that the nanowires had a hexagonal wurtzite structure. However, ZnO nanowires were not observed when the oxygen pressure increased from 10 Torr to 100 Torr. In roomtemperature cathodeluminescence spectra of the ZnO nanowires, the intensity of ultra-violet emission at 380 nm increased with decreasing oxygen pressure, which indicated that the lower the oxygen pressure, the better the crystallinity of the ZnO nanowires.