• Toxicological Research
• /
• v.19 no.2
• /
• pp.99-104
• /
• 2003

This study was aimed to evaluate the effect of oxygen on motor activity and toxicity in male mice. The modified Porsolt forced swim test (FST) was used and the distance and time of movement by mice were analyzed in 15。C water bath for 20 minutes using the automatic Ethovision videotracking system. Analyses were carried out before and after 20 minutes of exposure to 10％-70％ concentration of normobaric oxygen. The effects of inspired oxygen tension on the distance and time of movement showed the similar trends, but changes in distance were more prominent. Both the distance and time of movement increased after exposure to 30％ and 40％ oxygen concentration. The distance and time of movement also increased upon exposure to 50％ and 60％ oxygen. In contrast, increases En movement and time under exposure to 21％ oxygen concentration were suppressed when exposed to over 50％ oxygen concentration. With exposure to 10％ oxygen, there was a significant decrease in the distance of movement and a slight suppression of movement time. During the swim test, 12.5％, 37.5％, and 87.5％ of the mice drowned after exposure to 10％, 60％, and 70％ oxygen concentration, respectively. These results suggest that motor activity can be enhanced by inspired oxygen up to 40％ concentration. When hypoxic and hyperoxic oxygen exposure over 50％, motor activity is reduced and toxicity may be induced.

• IE interfaces
• /
• v.18 no.2
• /
• pp.178-183
• /
• 2005

In this study, changes in memory performance, blood oxygen saturation and heart rate according to 30% concentration oxygen supply were observed. Ten healthy male and female college students (male:$25.8{\pm}0.8$ years, female: $24.2{\pm}1.9$ years) participated in the study. The experiment was performed as Rest (1min.), Control task (1min.), Word presentation (1min.), Reaction time task (1min.), Distractor (2min.), and Word recall (1min.) and the physiological signals such as blood oxygen saturation and heart rate were measured throughout the stages. Subjects who received 30% oxygen recalled more words than those who received 21% oxygen, which shows 30% oxygen supply has influenced positively on memory cognitive performance. When 30% concentration oxygen is supplied, the blood oxygen saturation in the task phases was increased and the heart rate decreased when comparing to 21%. It means that 30% oxygen can stimulate brain activation by increasing actual blood oxygen concentration in the process of cognitive performance, and the heart rate decreases because enough oxygen is supplied to process the cognitive performance.

• Korean Journal of Materials Research
• /
• v.21 no.11
• /
• pp.617-622
• /
• 2011

The effect of oxygen on the shape memory characteristics in Ti-18Nb-6Zr-XO (X = 0-1.5 at%) biomedical alloys was investigated by tensile tests. The alloys were fabricated by an arc melting method at Ar atmosphere. The ingots were cold-rolled to 0.45 mm with a reduction up to 95% in thickness. After severe cold-rolling, the plate was solution-treated at 1173 K for 1.8 ks. The fracture stress of the solution-treated specimens increased from 450 Mpa to 880 MPa with an increasing oxygen content up to 1.5%. The fracture stress increased by 287MPa with 1 at% increase of oxygen content. The critical stress for slip increased from 430 MPa to 695 MPa with an increasing oxygen content up to 1.5 at%. The maximum recovery strain of 4.1% was obtained in the Ti-18Nb-6Zr-0.5O (at%) alloy. The martensitic transformation temperature decreased by 140 K with a 1.0 at% increase in O content, which is lower than that of Ti-22Nb-(0-2.0)O (at%) by 20 K. This may have been caused by the effect of the addition of Zr. This study confirmed that addition of oxygen to the Ti-Nb-Zr alloy increases the critical stress for slip due to solid solution hardening without being detrimental to the maximum recovery strain.

• Journal of the korean society of oceanography
• /
• v.31 no.1
• /
• pp.18-22
• /
• 1996

The effect of exogenous oxygen on hydrogen photoproduction was examined in the synchronously grown cells of marine Synechococcus sp. Miami BG 043511 under conditions of high cell density (0.6-0.8 mg chl-${\alpha}$ $ml^{-1}$) and high light intensity (1000 ${\mu}$E $m^{-2}$ $s^{-1}$). Hydrogen evolution after 20-h incubation did not decline under the initial oxygen concentrations up to 20%, but declined by half under 34% oxygen. 50% and 100% oxygen gas phase did not completely inhibit the hydrogen photoproduction during 40-h incubations. After 2-day pretreatment under 100% exogenous oxygen the hydrogen photoproduction capabilities were not irreversibly inhibited, which was demonstrated in the subsequent 9-day incubation under initial 0, 50 and even under 100% oxygen gas phase. This strain could be useful for developing a hydrogen photoproduction system under atmospheric oxygen concentration.

• Microbiology and Biotechnology Letters
• /
• v.26 no.6
• /
• pp.529-536
• /
• 1998

In a 20 L fermentor experiments the level of dissolved oxygen (D.O.) strongly affected growth and PHBV production of Azotobacter vinelandii UWD. A higher D.O. (5%) increased specific cell growth rate two folds but PHBV production was 17 folds higher (62.3 wt%) at a lower D.O.(1%) level. D.O. level was not a good criterion to evaluate the effect of aeration on fermentation characteristics of A. vinelandii UWD. This strain maintained an equal D.O. (5%) by decreasing its oxygen consumption rate when oxygen transfer rate (OTR) was decreased by changing agitation speed at a fixed aeration rate. OTR rather than D.O. was a criterion to explain the effect of aeration on the cell growth and PHBV production. At 5% D.O. with a lower 0TR cell growth rate decreased but PHBV production (57.3 wt%) approached to that (62.3 wt%) of the lower (1%) D.O.

• Journal of Oriental Neuropsychiatry
• /
• v.19 no.3
• /
• pp.129-142
• /
• 2008

Objective: The purpose of this study was to evaluate the antioxidative effects of the extract of Scolopendra subspinipes which has been used mainly for detoxication in the oriental medicine and reported to have sedative action, antiinflammatory effect, antihypertensive property and immunity enhancing activity. Method: Inhibitory activities on oxygen radical generating enzymes (aldehyde oxidase and xanthine oxidase) and increasing activities on oxygen radical scavenging enzymes (superoxide dismutase, glutathione peroxidase, glutathione-S-transferase) were investigated. Furthermore, the content of glutathione in the mouse brain, DPPH radical scavenging activity and also anti-lipid peroxidative effects in vivo and in vitro were estimated. Results: The extract showed weak inhibitory effects on the activities of aldehyde oxidase and xanthine oxidase which are oxygen radical generating enzymes. The extract inhibited lipid peroxidation with 26.1% against control group at 500 mg/kg in vivo and with 11.2% against control group at 10 mg/kg in vitro in a dose-dependent manner, which means this drug may protect radical-induced cell damages. The extract showed dose-dependently the scavenging effect on DPPH radical with 24.8% activity at 10 mg/ml in vitro. The extract enhanced the activities of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase, which are oxygen radical scavenging enzymes, with 28.9%, 22.3% and 23.1%, respectively at 500mg/kg in vivo. Finally, this extract strongly increased the glutathione content in the mouse barin. Conclusion: Above results indicated that Scolopendra subspinipes can be useful for the protection or treatment of some diseases caused by reactive oxygen species.

• Journal of Biomedical Engineering Research
• /
• v.39 no.5
• /
• pp.175-182
• /
• 2018

The purpose of this study is to evaluate the reliability and effectiveness of hyperbaric oxygen chamber on alcohol-induced oxidative stress and hangover. In order to evaluate them, 20 healthy adults were tested for blood and hangover stress tests. When an exponential change was examined after 3 interventions (hangover drink, hyperbaric oxygen chamber, and normal chamber as placebo effect) of 1 hour, the heart rate of subjects experiencing a hyperbaric oxygen chamber showed a statistically significant decrease (p < 0.001). The tests of blood alcohol concentration (BAC) as for exquisite hematology analysis, glucose, creatinine, and AST (aspartate aminotransferase) as well as ALT (alanine aminotransferase) used as liver-damage indicator show that the hyperbaric chamber has the effective effect. In the test of lactic acid, CRP (c-reactive protein), cortisol, and creatinine, the hyperbaric chamber shows much more excellent effect than the hangover drink and normal chamber as control groups. Further studies on hyperbaric oxygen chamber intervention including this study could be very helpful for improving lives of both the patients and healthy people.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.11 no.1
• /
• pp.43-51
• /
• 2009

The cotton, wool, cotton/wool blended(80:20) and tencel fabrics were treated with low temperature oxygen or argon plasma, enzymes(cellulase or protease), or oxygen plasma-enzyme and examined for their weight loss and conditions for treatment for the environment friendly finishing. In the plasma treatment argon gas had better effect on the weight loss than oxygen gas did and the weight loss of all the fabrics was increased as increasing discharge power and discharge time. The weight loss of cotton, wool, cotton/wool blended(80:20) fabrics decreased in a large measure after 1 hr but that of tencel didn't decrease after 1 hr. In case of cellulose fibers oxygen gas plasma induced chemical functional groups on the surface of substrate more than argon gas plasma did so the weight loss of wool was larger than that of cotton, tencel fabrics in oxygen plasma-enzyme treatment. The weight loss of cotton and tencel fabrics decreased the initial stage because oxygen plasma pre-treatment caused cross linking as well as etching effect but argon plasma pre-treatment didn't. The plasma pre-treatment cleared the way for enzyme treatment on the whole but oxygen plasma pre-treatment bear in hand the increase of weight loss more or less because of the cross linking on the surface of cellulose fibers. The appropriate conditions for plasma treatment was 10-1Torr, 40W for 30minutes and for cellulase treatment were enzyme concentration of $3g/{\ell}$, pH 5, $60^{\circ}C$ for 1hr and for protease treatment were enzyme concentration of $4g/{\ell}$ pH 8, $60^{\circ}C$ for 1hr.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.4
• /
• pp.55-62
• /
• 2012

In this study, it was observed through the ability of performing secondary tasks and baseline fetal heart rate how the supply of lavender, peppermint and highly concentrated oxygen (40%) affected distraction due to the performance of secondary tasks in the driving environment. Twelve male university students conducted secondary tasks while driving in the environments (6 in total) mixed and designed with oxygen concentration (21%, 40%) and the condition of odors (Normal, Lavender, Peppermint). The test was proceeded in order of stable state (5mins), driving (5mins), and secondary tasks (1min), and by extracting ECG data from every section by 30secs, the mean value of baseline fetal heart rate was calculated. As a result of analysis, in the ability of performing secondary tasks, a percentage of correct answers showed no difference in oxygen concentration and the condition of odors (p > 0.05). In performance completion time, a percentage of correct answers decreased showing a statistically significant difference in the condition of odors compared with the condition where odors were not provided (p < 0.05). As for baseline fetal heart rate, in the comparison between sections, while performing secondary tasks, it increased showing a significant difference compared with stable state and driving state (p < 0.05). The effect of interaction was observed in oxygen concentration and the condition of odors. When odors were not provided, baseline fetal heart rate decreased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05), however, when peppermint was provided, it increased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05). In conclusion, the fact that the condition of odors increased the ability of calculation, and when only the highly concentrated oxygen was provided, parasympathetic nerve system was activated, however, when highly concentrated oxygen was provided with peppermint at the same time, sympathetic nervous system (sns) was activated, which had a negative effect on the autonomic nervous system was drawn.

• Journal of Energy Engineering
• /
• v.2 no.3
• /
• pp.285-292
• /
• 1993

A cylindrical-shape, horizontal furnace was used to investigate the effect of particle size on the pulverized coal combustion behavior. Three differently-sized fractions (5, 30, and 44 microns in average diameter) of high-volatile bituminous coal, were burned in the test furnace. Ignition characteristics of pulverized coal flame were determined through the amount of methane in the carrier gas for the self-sustaining flame. Easiest ignition occurred with the immediately-sized coal particles. Ignition of coal jet flame appeared to occur through a gas-phase homogeneous process for particles larger than 30 microns. Below this limiting size, heterogeneous process probably dominated ignition of coal flame. Oxygen concentration of combustion air was varied up to 50%, to determine the oxygen-enrichment effect on the coal ignition behavior. Oxygen enrichment of primary air assisted ignition behavior of pulverized coal flame. However, enrichment of secondary air didn't produce any effect on the ignition behavior.