• Biomedical Science Letters
• /
• v.9 no.2
• /
• pp.75-84
• /
• 2003

To evaluate the influence of hepatic oxygen free radical systems on liver injury by topical p-phenylenediamine (PPD) application on rat skin, PPD (25 mg/16.5 $\textrm{cm}^2$) was topically applied to the abdominal region 5 times every other day and sacrificed. By PPD treatment, increasing rate of liver weight/body weight (%), serum activities of alanine aminotransferase and aspartate aminotransferase and decreasing rate of microsomal glucose-6-phosphatase activity were higher in the rats fed tungstate supplemented diet than those fed a standard diet. These findings indicate that group fed tungstate supplemented diet have more severe liver injury compared with group fed standard diet on topical PPD application. However, the activities of oxygen free radical generating enzymes such as xanthine oxidase (XO) and cytochrome P450 dependent aniline hydroxylase and those of oxygen free radical scavenging enzymes were not found to be different between these two animal groups. In the present study, a novel monitoring method to detect the generating of oxygen free radicals in liver extract was devised. Throughout this method, the oxidized PPD produced by oxygen free radicals was determined colorimetrically. The increasing rate of PPD oxidation by liver homogenate was higher in tungstate fed animals than in standard diet fed ones. Among the fractionations of liver extract, the mitochondrial and postmitochondrial fractions in the liver extract of tungstate fed animals led to a higher availability of PPD oxidation by PPD treatment compared with standard diet fed ones. In conclusion, these results suggest that an enhanced liver injury in tungstate fed animals treated with PPD may be due to oxygen free radicals produced in other systems except oxygen free radicals generating from cytosolic XO system. Especially, oxidative availability by PPD can be used for oxygen free radical detection in some tissue.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.5
• /
• pp.753-758
• /
• 2016

Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull) and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdust; BR, Beef cattle manure+rice hull) were determined based on oxygen uptake rate measured by a pressure sensor method. A broad range of oxygen uptake rates (0.3 to 33.3 mg $O_2/g$ VS d) were monitored as a function of moisture level and composting feedstock type. The maximum oxygen consumption of each material was observed near the saturated condition, which ranged from 75% to 98% of water holding capacity. The optimum moisture content of BS and BR were 70% and 57% on a wet basis, respectively. Although BS's optimum moisture content was near saturated state, its free air space kept a favorable level (above 30%) for aerobic composting due to the sawdust's coarse particle size and bulking effect.

• Child Health Nursing Research
• /
• v.13 no.3
• /
• pp.299-307
• /
• 2007

Purpose: To investigate the effect of nonnutritive sucking(NNS) on the heart rate, oxygen saturation, and behavioral state of premature infants. Method: From December 15, 2004 to February 15, 2005, 20 premature infants hospitalized in the neonatal intensive care units were assigned to an experimental group (10), or a control group (10). Circular pacifiers for premature infants (Johnson, U.S.A.), which had been packed with $2{\times}2$ gauzes to create a vacuum, were used for 5 minutes, one hour after feeding for 5 days. Heart rates and oxygen saturation were checked every minute for 10 minutes once a day and behavioral states were monitored through video recording at the same time. Results: Changes in heart rate, oxygen saturation and behavioral state were found to show significant differences between the experimental group and the control group according to the point in time, and interactions were found between the group and the point of time. However, for behavioral state, no significant difference was found between the experimental group and the control group after the NNS was removed. Conclusion: From the results of this study it is possible to conclude that NNS is a positive intervention to bring about increased oxygen saturation and soothed behavioral state for premature infants.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.80-83
• /
• 2005

In this work, effects of oxygen plasma on surface characteristics of carbon fibers were investigated in mechanical properties interfacial of carbon fibers-reinforced composites. The surface properties of the carbon fibers were determined by acid/base values, FT-IR, and X-ray photoelectron spectroscopy (XPS). Also, the mechanical properties of the composites were studied in and critical stress intensity factor ($K_{IC}$) and critical strain energy release rate mode II ($G_{IIC}$) measurements. As experimental results, the $O_{lS}/C_{lS}$ ratio of the carbon fiber surfaces treated by oxygen plasma was increased compared to that of untreated ones, possibly due to development of oxygen-containing functional groups. The mechanical properties of the composites, including $K_{IC}$ and $G_{IIC}$ had been improved in the oxygen plasma on fibers. These results could be explained that the oxygen plasma was resulted in the increase of the adhesion of between fibers and matrix in a composite system.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.2
• /
• pp.346-349
• /
• 2010

Coenzyme $Q_{10}$ ($CoQ_{10}$) production from Rhizobium radiobacter T6102 was monitored under various oxygen supply conditions by controlling the agitation speeds, aeration rates, and dissolved oxygen levels. As the results, the $CoQ_{10}$ production was enhanced by limited oxygen supply. To investigate whether the $CoQ_{10}$ production is associated with its physiological functions of electron carrier and antioxidant, the effects of sodium azide and hydrogen peroxide on the $CoQ_{10}$ production were studied, showing that the $CoQ_{10}$ contents were slightly enhanced with increasing sodium azide (up to 0.4 mM) and hydrogen peroxide (up to $10\;{\mu}M$) concentrations. These results suggest the plausible mechanism where the limited electron transfer stimulating the environments of limited oxygen supply and oxidative stress could accumulate the $CoQ_{10}$, providing the relationship between the $CoQ_{10}$ physiological functions and its regulation system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.1
• /
• pp.87-90
• /
• 2006

In case of preparation of ITO thin film for using top electrode of Top-emitting Organic Light Emitting Diodes(TOLEDs), the ITO thin film should be prepared at room temperature and low oxygen gas flow condition in order to reduced the damage of organic layer due to the bombardment of highly energetic particles such as negative oxygen ions which accrued from the plasma. In this study, the ITO thin film with high optical transmittance and low resistivity prepared as a function of oxygen gas (0 ${\~}$ 0.8 sccm) and Ar gas was fixed at 20 sccm by the Facing Targets Sputtering (FTS) method. The electrical and optical properties of ITO thin films were measured by Hall effect measurement, UV/VIS spectrometer, respectively In the results, we obtained the ITO thin film with lowest resistivity($3{\times}10^{-4} {\Omega}{\cdot} cm$) at oxygen gas flow 0.2 sccm and optical transmittance over $80\%$ at oxygen gas flow over 0.2 sccm.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.21 no.1
• /
• pp.41-47
• /
• 2015

The objective of this study was to evaluate quality properties including acid value (AV) and peroxide value (POV) of brown rice packaged with antioxidant allyl mercaptan sachet or oxygen scavenging sachet. To prepare the antioxidant allyl mercaptan sachet, allyl mercaptan was encapsulated by rice flour and put in small roll paper pouch. The oxygen scavenging sachet consists of diatomite, sodium L-ascorbate and activated carbon. The results of this study showed that antioxidant allyl mercaptan sachet had no antioxidant effect on deterioration of brown rice, but oxygen scavenging sachet effectively inhibited rancidity of brown rice. Therefore, the developed oxygen scavenging sachet can be effectively utilized in food packaging system for quality stability.

• Aerospace Engineering and Technology
• /
• v.5 no.2
• /
• pp.134-142
• /
• 2006

Sub-cooling of cryogenic propellant by helium injection is one of the most effective methods for suppressing bulk boiling and keeping sub-cooled liquid oxygen before rocket launch. In order to design the cooling system, understanding of the limitations of heat and mass transfer is required. In this paper, an analytical model for the helium injection system is presented. This model's main feature is the representation of bubbling system using finite-rate heat transfer and instantaneous mass transfer concept. With this simplified approach, the effect of helium injection to liquid oxygen system under several circumstances is examined. Experimental results along with simulations of single bubble rising in liquid oxygen and bubbling system are presented with various helium injection flow rates, and with change of oxygen chamber pressure.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.118-120
• /
• 2009

We reported that the evidence of oxygen doping to copper-phthalocyanine (CuPc) by $O_2$-plasma treatment to Au electrode of inverted top emitting organic light emitting diodes (ITOLEDs). The operation voltage of OLEDs at 150 mA/$cm^2$ decreased from 16.1 to 10.3 V as oxygen atoms indiffued to CuPc layer using $O_2$-plasma. Synchrotron radiation photoelectron spectroscopy results showed that a new bond of Cu-O appeared and the energy difference between the highest occupied molecular orbital and $E_F$ is lowered by 0.20 eV after plasma treatment. Thus the hole injection barrier was lowered, reducing the turn-on voltage and increasing the quantum efficiency of OLEDs.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.7
• /
• pp.2255-2259
• /
• 2012

Aggregation of titania nanotubes (TNTs) fabricated by hydrothermal method were calcined in air and dry nitrogen; Changes in morphology and crystallinity of the nanotubes were studied by means of TEM, EDX, and XPS. EDX patterns and XPS spectra proved that there were a certain densities of oxygen vacancies in TNTs annealed in $N_2$. The photocatalysis experiments revealed TNTs/$N_2$ possesses significantly higher photocatalytic efficiency than TNTs annealed in dry air to degrade methylene blue. The correlation between oxygen vacancies and photocatalytic property may be attributed to: 1) oxygen vacancies might have affected results on water molecules adsorption and increase of the hydroxyl concentration; and 2) oxygen vacancies resulted in some changes in electronic structure of TNTs/$N_2$ aggregation and Fermi level extends into the conducting band.