• 대한전자공학회논문지
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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.

• 한국전기전자재료학회논문지
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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.

• 대한본초학회지
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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.

• 한국가축번식학회지
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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.

• 한국미생물·생명공학회지
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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.

• 한국표면공학회지
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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.

• 대한약리학회지
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• 제26권2호
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• pp.161-166
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• 1990

Kallikrein-kinin계는 신장의 혈류역학과 수분 및 전해질 배설의 조절자로서 역할을 하는 것으로 알려져 있다. Kallikrein-kinin계의 유효한 펩타이드중 하나인 bradykinin(BK)을 신동맥에 주입시 전해질 배설이 증가하는데 이 작용이 신혈류역학적 변동에 기인하는지 또는 신세뇨관의 전해질 운반에 대한 직접적인 작용에 기인하는지 아직 확실치 않다. 따라서 본 연구에서는 원위세뇨관(DT)과 피질집합관(CCT)에서의 전해질운반 의존성 산소소비에 대한 BK의 영향을 관찰하였다. BK$(0.1\;{\mu}M)$은 DT과 CCT의 산소소비를 유의하게 감소시켰으며 이 작용은 Na부재시 나타나지 않았고 ouabain전처치에 의해 차단되었다. 또한 이 작용은 mepacrine에 의해 유의하게 차단되었으며 indomethacin에 의하여는 차단되지 않았다. 이상의 결과는 BK이 DT과 CCT에서 Na운반과 관련한 산소소비를 억제시키며 이 작용에는 prostaglandin들이 관여하고 있지 않음을 시사한다.

• 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.

• 한국정밀공학회지
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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

• 한국재료학회지
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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.