• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.1-7
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• 2014

The purpose of this study was to investigate the nitrification characteristics of biological aerated filter (BAF) packed with ceramic media, especially focusing on nitrite build-up during nitrification. When increasing the nitrogen load above $1.63kgNH_4{^+}-N/m^3{\cdot}d$, ammonium removal efficiency decreased to less than 60% and the nitrite ratio ($NO_2{^-}-N/NO_x-N$) of higher than 75% was achieved due to the inhibitory free ammonia (FA, $NH_3-N$) concentration and oxygen limitation. FA inhibition, however, is not recommended strategy to promote nitrite build-up since FA concentration in the reactor is coupled with decreased ammonium removal efficiency. Nitrite ratio in the effluent was also affected by aeration rate and influent ammonium concentration. Ammonium oxidation was enhanced at a higher aeration rate regardless of influent ammonium concentration but, the nitrite ratio was dependent on both aeration rate and influent ammonium concentration. While a higher nitrite ratio was obtained when BAFs were fed with $50mgNH_4{^+}-N/L$ of influent, the nitrite ratio significantly decreased for a greater influent concentration of $200-300mgNH_4{^+}-N/L$. Taken together, aeration rate, influent ammonium concentration and FA concentrations kept in the BAF were found to be critical variables for nitrite accumulation in the BAF system.

• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.101-107
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• 2000

This experiment was conducted to investigate the effect of NA formation in the human body with salted and dried yellow corvenia(Gulbi, Pseudosciaena manchurica) steamed for 30 minutes and incubated in 10 ml simulated saliva and 40 ml gastric juice at 37。C for 2 hours. And the experiment studied the NA formation after nitrite, thiocyanate and ascorbic acid treatment under simulated gastric conditions. N-nitrosodimethylamine(NDMA) was not detected when nitrite was not added to the digestate mixture. And then increasing the nitrite concentration from 0.5 mM to 8 mM gave a slight increase in the NDMA formation at all level of Gulbi utilized in the experiment. In contrast to the change of the nitrite concentration, the increase of the amount of Gulbi didn't show any marked influence on NDMA formation. At all level of thiocyanate(1∼6.4 mM) tested, concentration of NDMA was still proportional to the nitrite concentration. In the catalytic ability of thiocyanate at another high level of nitrite(100 mM) no catalytic activity was observed up to the level of 8mM thiocyanate. The same amounts of salted fish(10 g) and ascorbic acid levels in each single digestate were used to prevent NDMA formation. No prevention effect was observed at nitrite concentration of 0.5 mM and 1 mM. Most importantly, the decrease of NDMA concentration, by the increase of ascorbic acid absolutely, was remarkably shown when nitrite concentration was high. On the contrary, according to the degree of ascorbic acid, the higher the amount of nitrite the higher the prevention of NDMA formation.

• Journal of fish pathology
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• v.20 no.3
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• pp.291-297
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• 2007

The effect of aspirin on the recovery of nitrite-induced methemoglobinemia in cultured eels (Anguilla japonica) was studied. Methemoglobinemia was induced by exposing eels to nitrite (120 ㎎ NO2-N/ℓ) for 24 hr. The nitrite exposed eels were bathed in 20 ppm aspirin solution (Aspirin), 0.8 % NaCl solution (NaCl), 20 ppm aspirin plus 0.8% NaCl solution (NaCl + Aspirin) and 50% nitrite free water(control) for 24 hr to recover from nitrite toxicity. Peripheral blood was taken from the arterious bulb from all groups to analyse hematocrit value, hemoglobin concentration, and nitrite concentration of the blood. Histopathological features of gill were also observed. Aspirin and control groups were more effective than NaCl and NaCl + Aspirin groups in recovery of hematocrit value and hemoglobin concentration, methemoglobin rate and nitrite concentration. The histopathological features on the gill of aspirin group were similar to those of normal eels, but other groups showed focal hyperemia in the lamellar carpillaries, epithelial hyperplasia. These results suggested that aspirin was very effective to recover from methemoglobinemia in nitrite-induced cultured eels.

• Journal of fish pathology
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• v.26 no.1
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• pp.1-9
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• 2013

The acute toxicity and sublethal effects of nitrite on the dark-banded rockfish, Sebastes inermis (mean body weight: $83.3{\pm}7.2$ g), were studied under static conditions for a period of 96 h. The acute toxicity of nitrite was at the 50% lethal concentration ($LC_{50}$) of 700 mg/L. The sublethal effects on selected hematological parameters of the dark-banded rockfish, such as its osmolality, hematocrit, cortisol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST), were measured after 0, 6, 12, 24, 48, 72, and 96 h of exposure to 0, 50, 100, 200, 400, or 700 mg/L nitrite. Sublethal nitrite caused a progressive reduction in the hematocrit of the fish, depending on the nitrite concentration and the exposure period. Exposure to 100-700 mg/L nitrite for 96 h caused a reduction in the hematocrit and an increase in cortisol, ALT, and AST compared with the control levels. Abnormal ultrastructural changes in the gills and liver tissues were observed in fish exposed to 700 mg/L nitrite for up to 96 h compared with the control tissues. Ultrastructural changes included atrophic gill mitochondria and hepatocytes that developed smooth endoplasmic reticulum and atrophic mitochondria. Although no rockfish mortality occurred at 500 mg/L nitrite, all the hematological parameters examined responded adversely to a nitrite dose of 200 mg/L for 96 h. These results show that although the acute toxic concentration of nitrite for the dark-banded rockfish is > 700 mg/L, sublethal concentrations of nitrite also negatively affect its hematological parameters.

• Journal of fish pathology
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• v.36 no.2
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• pp.361-368
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• 2023

Juveniles of the white leg shrimp Litopenaeus vannamei (Weight 0.18±0.08 g) were exposed to nitrite-N at 0, 25, 50, 100, 200 and 400 mg/L for 72 hours, and the lethal concentration, heamolymph and genes regulation were evaluated. The lethal concentration 50 (LC₅₀) of L. vannamei exposed to nitrite-N was 141.2 mg/L at 25℃ and 33 psu. In Total protein, total cholesterol, and BUN in heamolymph temporarily increased after the start of the experiment and then stabilized, but glucose, an indicator of stress, decreased over time in the entire experimental group, and creatines, an indicator of tissue damage, decreased with nitrite concentration until the first 12 hours. The genes of immune-related showed that masquerade-like serine proteinase(Mas) increased at 50 and 400 ppm for 24 hours, and then gradually decreased depending on concentration. In the case of prophenoloxidase, it was highest at 400 ppm for 40 hours, and other genes(Ras-related nuclear protein, Masquerade-like serine proteinase, proPO-activating enzyme) showed a response for 48 hours and then gradually decreased. The results of this study indicate that exposure to nitrite can affect the survival and hematological physiology of L. vannamei.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.282-285
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• 2001

The microbial community structure and in situ spatial distribution of ammonia oxidizing and nitrite oxidizing bacteria in nitrifying biofilm of an upflow biological aerated filter system were investigated. The reactor had been continuously operated under high free ammonia concentration and low DO concentration for nitrite accumulation more than 2 years before the experiment. Fluorescence in situ hybridization

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1789-1797
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• 2000

The objective of this study was to assess parameters affecting nitrite accumulation, which offers advantages in terms of less aeration energy and carbon consumption for denitrification. The influence of the alkalinity to $NH_4{^+}-N$ concentration ratio, pH, FA(free ammonia) concentration and temperature on nitrite accumulation was investigated. The experiment was performed with supernatant from dewatering process of anaerobic digested sludge using a submerged biofilm reactor. The influent contains high strength of ammonium nitrogen and the alkalinity was insufficient for complete nitrification. An increased nitrite accumulation was observed with increase in alkalinity to $NH_4{^+}-N$ concentration ratio. The increase in alkalinity to $NH_4{^+}-N$ concentration ratio has been a maior reason for the high pH value and FA concentration in the reactor. It can be considered that selective inhibition of Nitrobacter can be causes of nitrite accumulation. The nitrite accumulation increased with increment of temperature at fixed alkalinity to $NH_4{^+}-N$ concentration ratio.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.33-39
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• 2004

Objective:Nitric oxide(NO) has been known to be associated with tolerance and preference to alcohol. It has also been known to affect various alcohol drinking behavior, alcohol withdrawal symptoms and alcohol- induced brain damage. The purpose of this study was to determine the difference, among alcohol dependence group, alcohol drinking group and abstinence group, in serum concentration of nitrite, a stable metabolite of NO, and it's relationship to clinical and biochemical markers of alcoholism. Methods:Forty subjects diagnosed as alcohol dependence according to DSM-IV diagnostic criteria were evaluated for the clinical characteristics and biochemical markers of alcohol dependence including nitrite with their CIWA-Ar scores checked just after admission. Thirty-nine healthy controls were also evaluated, divided into twenty-three alcohol drinking group and sixteen abstinence group. Clinical characteristics were evaluated by CIWA-Ar, CAGE and AUDIT questionnaires. Aspartate aminotransferase(AST), alanine aminotransferase (ALT), gamma glutamyltransferase(GGT) and mean corpuscular volume(MCV) were used as the biochemical markers of alcohol dependence. Serum nitrite concentrations were measured by Griess reaction. Results:1) The concentrations of nitrite in alcohol dependence patients were not different from those in the control subjects. 2) There were no significant association between the nitrite concentrations and the CIWA-Ar scores in alcohol dependence patients. 3) Nitrites are significantly increased in alcohol dependence group and alcohol drinking group compared with abstinence group. Conclusions:These findings suggest that serum nitrite concentration has no relation with alcohol withdrawal symptoms, but alcohol drinking increases serum nitrite concentration influenced by general condition of the body.

• Journal of Life Science
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• v.11 no.4
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• pp.321-327
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• 2001

The purpose of this study was to investigate the nitrite scavenging activity of the ethanol and water extracts obtained from Hizikia fusiforme and Sargassum fulvelum using sodium nitrite under different pH conditions. The nitrite scavenging activity was appeared in all the extracts examined and it showed the highest value at pH 1.2 The ethanol extract of Hizikia fusiforme provided higher activity than the water extract of that. Ohterwise, the nitrite scavenging activity of Sargassum fulvelum ethanol extract was similar to that Sargassum fulvelum water extract. There was significant difference among concentration of extracts Hizikia fusiforme and Sargassum fulvelum. Also, nitrite scavenging activity of the extracts Hizikia fusiforme and Sargassum fulvelum decreased with higher pH condition. In addition, the activity was increaed with higher concentration of extracts Hizikia fusiforme and Sargassum fulvelum in the course of reaction time 30 minute to 3 hour.

• Journal of fish pathology
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• v.36 no.2
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• pp.349-360
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• 2023

Common carp (Cyprinus carpio) (Weight 23.05 ± 6.98 g, Length 12.65 ± 1.38 cm) were exposed to waterborne nitrite at 0, 50, 100, 200, 400 and 800 mg NO₂ ^-/L for 96 hours. The lethal concentration 50 (LC₅₀) of C. carpio exposed to waterborne nitrite was 398.6 mg NO₂ ^-/L. Hemoglobin, hematocrit and RBC count were significantly decreased by waterborne nitrite exposure. The MCV (mean mean corpuscular volume) (µl), MCH (mean corpuscular hemoglobin) (pg) and MCHC (mean corpuscular hemoglobin concentration) (%) were significantly increased. The inorganic component, plasma calcium, was significantly increased, and the organic components such as plasma cholesterol and total protein were significantly increased showing a similar tendency with calcium. In enzymatic components, the AST and ALT were also significantly increased by nitrite exposure. The results of this study indicate that exposure to nitrite can affect the survival and hematological physiology of C. carpio.