• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.222-228
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• 2003

Optimum extraction conditions for yield, browning color, electron-donating ability, nitrite-scavenging effect, total polyphenol content, and tyrosinase-inhibitory activity of Flammulina velutipes were determined using response surface methodology through central composite design. Yield of F. velutipes was affected by ethanol concentration, and browning color improved more with the increase of ethanol concentration than microwave power. Nitrite-scavenging effect was improved with increasing ethanol concentration and decreasing microwave power. Electron-donating ability and total polyphenol content were improved with increasing ethanol concentration and microwave power. Tyrosinase-inhibitory effect increased more with decrease in microwave power than with ethanol concentration. The optimal range of extraction conditions for effective component of F. velutipes were $47.21{\sim}76.05$ watt of microwave power, $10.25{\sim}43.56%$ of ethanol concentration, and 5.72 min of extraction time.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.57-63
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• 2013

A combined process consisted of a biofilm reactor and a continuously stirred-tank reactor (CSTR) was investigated for highly loaded ammonium wastewater treatment via nitrite accumulation. To enhance ammonium oxidizing bacteria over nitrite oxidizing bacteria on the surface of carriers, the biofilm reactor was operated at temperature of $35^{\circ}C$ for more than three months but the influent ammonium (500 mg-N/L) was partially oxidized to nitrite (240 mg-N/L). As pH was increased from 7.5 to 8.0, nitrite accumulation was fully achieved due to the inhibition of nitrite oxidizing bacteria under high free ammonia concentration. The biofilm reactor performance was severely deteriorated at the hydraulic retention time of 12 hr, at which incomplete nitrification of ammonia was observed. Various solubilization methods were applied to sewage sludge for enhancing its biodegradability and the combined method, alkaline followed by ultrasonic, gave the highest solubilization efficiency (58%); the solubilized solution was used as the external carbon source for denitrification reaction in CSTR. FISH analysis showed that the dominant microorganisms on the carriers were ammonium oxidizing bacteria such as Nitrosomonas spp. and Nitrospirar spp. but low amounts of nitrite oxidizing bacteria as Nitrobacter spp. was also detected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.4
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• pp.389-394
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• 2006

The change of antioxidative character by germination of brown rice was evaluated. From the total methanolic extract of brown rice, 2.5 mm-germinated brown rice, and 5 mm-germinated brown rice, SOD-like activity and nitrite scavenging ability were identified as antioxidative character. SOD-like activities and nitrite scavenging abilities of all samples were changed dose-dependently and germination-dependently. After successive partitioning with hexane, ethyl acetate (EtOAc) and water, each fraction was tested for these activities. SOD-like activities of all fractions were increased by germination, and especially hexane fraction and EtOAc fraction of 5 mm-germinated brown rice had more strong activities than 50 ppm vitamin C. The $EC_{50}$ values of SOD-like activity showed a gradual decrease by germination and that of EtOAc fraction of 5 mm-germinated brown rice was 17 ppm, which was lower concentration than that of 50 ppm vitamin C. The $IC_{50}$ values of nitrite scavenging ability at PH 1.5 also underwent a great decrease by germination and germinated brown rice had the nitrite scavenging ability at lower concentration than brown rice. The results suggest that SOD-like activity and nitrite scavenging ability are thought to be enhanced by the germination effect.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.200-206
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• 2006

In a biological aerated filter (BAF) packed with ceramic media (void fraction of BAF=0.32), nitrite accumulation was studied with the variation of hydraulic retention time (HRT) and superficial air velocity. Synthetic ammonium wastewater and petrochemical wastewater were fed at a constant load of $1.6kgNH_4^+-N/m^3{\cdot}d$. Ammonium removal rate was mainly affected by the superficial air velocity in BAF, but nitrite ratio($NO_2-N/NO_x-N$) in the effluent was dependent on both HRT and superficial air velocity. For a fixed HRT of 0.23 hr (corresponding to the empty bed contact time of 0.7 hr) ammonium removal rate was 73/90/92％ and nitrite ratio was 0.92/0.82/0.48 at the superficial air velocity of 0.23/0.45/0.56 cm/s, respectively. When HRT is increased to 0.9 hr with superficial air velocity ranging from 0.34 to 0.45 cm/s, the ammonium removal rate was 89％ on average. However nitrite ratio decreased significantly down to 0.13. When HRT was further increased to 1.4 hr, ammonium removal rate decreased, thereby resulting in the free ammonia ($NH_3-N$, FA) build-up and nitrite ratio gradually increased (>0.95). Although aeration rate and FA concentration at HRT of 0.23 hr were unfavorable for nitrite accumulation compared with those at HRT of 0.9 hr, nitrite ratio at HRT of 0.23 hr was higher. Taken together, HRT and nitrogen load were found to be critical, in addition to FA concentration and aeration condition, for nitrite accumulation in the BAF tested in the present study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.961-966
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• 2006

This study was worked out to investigate antioxidant activity of solvent extracts from wild grape skin by measuring electron donating ability (EDA), reducing power, superoxide dismutase (SOD)-like activity, thiobarbituric acid reactive substances (TBARS) and nitrite scavenging ability. Total phenolic compound and flavonoids contents were the highest in ethyl acetate extract, $54.4{\pm}1.18\;mg/100\;g$ and $645.1{\pm}5.05\;mg/100\;g$, respectively. The EDA and reducing power of solvent extracts from wild grape skin were proportionally increased with concentration and ethyl acetate extract $(79.2{\pm}0.06%)$ showed the stronger than BHT $(74.1{\pm}0.15%)$ at concentration of $100\;{\mu}g/mL$, especially. SOD-like ability of ethyl acetate $(25.1{\pm}0.41%)$ and butanol $(20.2{\pm}0.13%)$ extracts were stronger than other extracts at concentration of $100\;{\mu}g/mL$. TBARS of ethyl acetate extract was higher than ascorbic acid. Nitrite scavenging ability of solvent extracts from wild grape skin (pH 2.5, $1000\;{\mu}g/mL$) were in order of ethyl acetate $(90.5{\pm}0.75%)$>butanol $(65.9{\pm}2.16%)$>hexane $(58.1{\pm}1.74%)$>chloroform $(55.4{\pm}1.02%)$>water $(40.9{\pm}0.35%)$. Antioxidant activity of solvent extracts from wild grape skin was the highest in ethyl acetate extract from the results of our experiments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.677-682
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• 2006

This study was conducted to investigate the effect of garlic extracts on electron donating ability nitrite-scavenging activity and N-nitrosodimethylamine (NDMA) formation. Content of total phenolic compounds was the highest in ethyl acetate extract. Electron donating ability was significantly increased with increasing sample concentration, as $88.0{\pm}1.53%$ from ethyl acetate extract and $77.5{\pm}0.8%$ from butanol extract in concentration of 10 mg/mL. Butanol extract from garlic with highest nitrite scavenging activity and inhibition effect of NDMA formation exhibited $96.9{\pm}0.75%$ and $68.6{\pm}1.15%$ in concentration of 10 mg/mL, respectively. The butanol extract was fractionated into 5 fractions using prep-LC. Nitrite-scavenging activity and inhibition effect of NDMA formation were excellent in fraction III, which further fractioned into 3 subfractions (III-a, III-b and III-c) using prep-LC. Of the 3 subfractions, its activity was the highest in the subfraction III-c. Therefore butanol extract of garlic was suggested to be effective inhibitor of NDMA formation.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.228-235
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• 2016

Nitrite accumulation is essential for constructing an anammox process. As the pH in the reactor exerts a complicated and strong influence on the reaction rate, we investigated its effects upon treatment of an ammonic wastewater (2,000 mgN/L) through modeling and experiment. The modeling results indicated that the reaction stability is strongly affected by pH, which results in a severe reduction of the 'stable region' of operation under alkaline environments. On a coordinate of the total ammonia nitrogen (TAN) concentration vs. pH, the maximal stable reaction rates and the maximal nitrite accumulation potentials could be found on the 'stability ridge' that separates the stable region from the unstable region. We achieved a stable and high ammonia oxidation rate (${\sim}6kgN/m^3-d$) with a nitrite accumulation ratio of ~99% when operated near the 'stability ridge'. The optimum pH that can be observed in experiments varies with the TAN concentrations utilized, although the intrinsic optimum pH is fixed. The direction of change is that the optimum operational pH falls as the TAN concentration increases, which is in excellent accordance with the observations in the literature. The optimum operational pH for 95% nitritation was predicted to be ~8.0, whereas it was ~7.2 for 55% partial nitritation to produce an anammox feed in our experimental conditions.

• Journal of Trauma and Injury
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• v.25 no.1
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• pp.17-24
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• 2012

Purpose: This study was performed to investigate whether therapeutic hypercapnia could attenuate systemic inflammatory responses in hemorrhagic shock in rats. Methods: Male Sprague-Dawley rats were mechanically ventilated and underwent pressure-controlled (mean arterial pressure: $38{\pm}1$ mmHg) hemorrhagic shock. At 10 minutes after the induction of hemorrhagic shock, the rats were divided into the normocapnia ($PaCO_2$=35-45 mmHg, n=10) and the hypercapnia ($PaCO_2$=60-70 mmHg) groups. The $PaCO_2$ concentration was adjusted by using the concentration of inhaled $CO_2$ gas. After 90 minutes of hemorrhagic shock, rats were resuscitated with shed blood for 10 minutes and were observed for 2 hours. The mean arterial pressure (MAP) and the heart rate were monitored continuously, and the results of arterial blood gas analyses, as well as the plasma concentrations of interleukin (IL)-6, IL-10, and nitrite/nitrate were compared between the normocapnia and the hypercapnia groups. Results: The MAP and the heart rate were not different between the two groups. The plasma concentration of IL-6 was significantly lower in the hypercapnia group than in the normocapnia group (p<0.05). The IL-10 concentration was not different and the IL-6 to IL-10 ratio was significantly lower in the hypercapnia group compared to the normocapnia group. The plasma nitrite/nitrate concentration of the hypercapnia group was lower than that of the normocapnia group. Conclusion: Therapeutic hypercapnia attenuates systemic inflammatory responses in hemorrhagic shock.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.574-580
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• 2003

Optimal extraction conditions for yield, browning color, electron donating ability, nitrite scavenging effect, total polyphenol content and tyrosinase inhibitory activity of Lyophyllum ulmarium were determined by using response surface methodology (RSM) through the central composite design. The extraction yield of Lyophyllum ulmarium was effected by ethanol concentration and browning color was improved with the increase of ethanol concentration than microwave power. The nitrite scavenging effect was improved with the increase of ethanol concentration and decrease of microwave power The electron donating ability, browning color, tyrosinase inhibitory activity and total polyphenol content were improved with the increase in ethanol concentration and microwave power. The optimal ranges of extraction conditions for effective components of Lyophyllim ulmarium were predicted as 60.05~102.75 watt of microwave power, 53.20~64.01% of ethanol concentration and 7.77 min of extraction time.