• The Korean Journal of Physiology
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• v.19 no.2
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• pp.203-213
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• 1985

This study was carried out to investigate whether the K-pNPPase activity in renal cortical slices can be used as an index for measuring the activity of $Na^+-K^+$ exchange pump. The K-pNPPase activity, Ouabain-sensitive oxygen consumption add intracellular electrolytes content in slices, and Na-K-ATPase activity in microsome were measured and the effects of ouabain and vanadate on these were observed. The results are as follows : 1) p-NPPase activity in slices increased linearly with incubation time during 60 minutes, and $K^+$-dependent, ouabain-sensitive fraction was about 55% of total p-NPPase activity. This value was almost the same through out the incubation time. 2) The concentrations of ouabain and vanadate for 50f inhibition of K-pNPPase activity were$7.0{\times}10^{-6}M$ and $1.3{\times}10^{-5}M$, respectively. 3) The ouabain-sensitive oxygen consumption in slices was reduced to 50% of control value by $6.3{\times}10^{-6}M$ ouabain or $2.5{\times}10^{-5}M$ vanadate. These concentrations were similar to those for 50% inhibition of K-pNPPase activity. 4) The trends of intracellular electrolytes change by ouabain and vanadate were similar to those of the change in K-pNPPase activity. 5) The Na-K-ATPase activity in microsome prepared from renal cortex was completely inhibited by $10^{-3}M$ ouabain or $10^{-3}M$ vanadate and the concentration for 50% inhibition was $1.2{\times}10^{-6}M$ in ouabain and $1.6{\times}10^{-6}M$ in vanadate, which were much lower than those for K-pNPPase activity or ouabain-sensitive oxygen consumption in slices. These results indicate that K-pNPPase activity measured in renal cortical slices is a better index for evaluating $Na^+-K^+$ exchange pump activity than Na-K-ATPase activity measured in microsome.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.122-129
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• 1998

It were reported that antifungal mechanism of Enterobacter cloacae is a volatile ammonia that produced by the strain in soil, and the production of ammonia is related to the bacterial urease activity. A powerful bacterium SH14 against soil-borne pathogen Fusarium solani, which cause root rot of many important crops, was selected from a ginseng pathogen suppressive soil. The strain SH14 was identified as Bacillus subtilis by cultural, biochemical, morphological method, and $API^{circledR}$ test. From several in vitro tests, the antifungal substance that is produced from B. subtilis SH14 was revealed as heat-stable and low-molecular weight antibiotic substance. In order to construct the multifunctional biocontrol agent, the urease gene of Bacillus pasteurii which can produce pathogenes-suppressive ammonia transferred into antifungal bacterium. First, a partial BamH I digestion fragment of plasmid pBU11 containing the alkalophilic B. pasteurii l1859 urease gene was inserted into the BamH I site of pEB203 and expressed in Escherichia coli JM109. The recombinant plasmid was designated as pGU366. The plasmid pGU366 containing urease gene was introduced into the B. subtilis SH14 with PEG-induced protoplast transformation (PIP) method. The urease gene was very stably expressed in the transformant of B. subtilis SH14. Also, the optimal conditions for transformation were established and the highest transformation frequency was obtained by treatment of lysozyme for 90 min, and then addition of 1.5 ${mu}g$/ml DNA and 40% PEG4000. From the in vitro antifungal test against F. solani, antifungal activity of B. subtilis SH14(pGu366) containing urease gene was much higher than that of the host strain. Genetical development of B. subtilis SH14 by transfer of urease gene can be responsible for enhanced biocontrol efficacy with its antibiotic action.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.414-419
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• 2010

Plants extracts are good resources to find functional compounds for human health. The following eight plants were collected and total phenolic contents were determined. Acer psedo-siebolianum showed the highest phenolic contents, 16.4 mg/g, whereas Cercidiphyllum japonica showed the lowest contents, 1.9 mg/g. The DPPH free radical scavenging capacities of the plant extracts showed high activity in following order : Acer ginnala ($21.3\;{\mu}g/mL$) > Cornus walteri ($23.9\;{\mu}g/mL$) > Distylum racemosum ($29.2\;{\mu}g/mL$) > Castanopsis cuspidata var. Thunbergii ($31.7\;{\mu}g/mL$) > Acer psedo-siebolianum ($34.6\;{\mu}g/mL$) > Thuijopsis dolabrata cv. Aurea ($53.1\;{\mu}g/mL$) > Cercidiphyllum Japonica ($115.2\;{\mu}g/mL$). Also the mushroom tyrosinase inhibitory activities of total extracts were determined at different concentration. D. racemosum extract showed highest (49.1% at 1,000 mg) in inhibitory activity than other seven extracts. The ethanol fraction $IC_{50}$ value: $118.1\;{\mu}g/mL$) from D. racemosum showed more inhibitory activity than ethyl acetate fraction ($IC_{50}$ value: $203\;{\mu}g/mL$). The ethanol fraction on showed no significant cytotoxicity in B16/F1 cells line up to $60\;{\mu}g/mL$. Over $80\;{\mu}g/mL$ of ethanol fraction showed cytotoxicity in B16/F1 cells. The melanin contents of cells were significantly attenuated by ethanol fraction in a dose-dependent manner. The $IC_{50}$ value of ethanol fraction was $75.4\;{\mu}g/mL$.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.231-239
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• 2006

In this study, we evaluated the efficiency of using sulfur-$CaCO_3$ complex pellet in the sulfur oxidizing autotrophic denitrification process for synthetic wastewater with high $CaCO_3$ concentration. The sulfur-$CaCO_3$ complex pellet was packed in reactor(R4). Influent ${NO_3}^--N$ loading rate was from 200 to $1,000g/m^3{\cdot}day$. During the operation, average denitrification efficiency of R4 was above 95%. Particularly, the denitrififation rate at $1,000g/m^3{\cdot}day$ loading was 98.96% for R4. High ${NO_3}^--N$ removal efficiency was determined in R4 compared with other reactors. Through $Ca^{2+}$ and alkalinity analyses, we calculated the supplied alkalinity from the packed $CaCO_3$ in the reactor. Sulfur-$CaCO_3$ complex pellet more effectively supplied alkalinity through the dissociation of $CaCO_3$ as compared with other media. Based on these results, sulfur-$CaCO_3$ complex pellet increased the pH buffering capacity while also providing the carbon source to the denitrifying bacteria. Denitrification efficiency of R4 was also higher than other reactors. ESEM pictures of sulfur-$CaCO_3$ complex pellet show higher porosity than that of the granular sulfur. Hence, more denitrifying bacteria attached on the sulfur-$CaCO_3$ complex pellet than on granular sulfur. It can be concluded that the sulfur-$CaCO_3$ complex pellet is a more suitable media for a sulfur oxidizing autotrophic denitrification process as it provides high denitrification efficiency.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.406-413
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• 2012

Effect of three additives, chitosan, ferric chloride, and MPE50 on membrane fouling reduction was studied. They were introduced with various dosing rate into activated sludge, and changes in filtration resistance measured by the batch cell filtration test were evaluated. Both the filtration resistance and the specific cake resistance were minimized at 20 mg/g-MLSS with chitosan, 70 mg/g-MLSS with ferric chloride, and 20 mg/g-MLSS with MPE50 addition, respectively. Introduction of the additives into the activated sludge resulted in reduction of not only cake resistance, but also fouling resistance. However, the chitosan addition to three different activated sludge resulted in three different optimal dose of 10, 20, 30 mg/g-MLSS, respectively. This implies that the optimal dose is dependent on sludge characteristics rather than a constant value. Overdose above the optimal dosage always aggravated filterability in all cases. Zeta potential of sludge flocs, relative hydrophobicity, floc size distribution, soluble EPS concentration and supernatant turbidity were measured in order to analyze fouling reduction mechanism. Nearly neutral surface charge along with the largest particle size was observed at the optimal dose. This could be explained by particle destabilization and restabilization mechanism as positively charged additives were injected into sludge flocs of negative surface charge. Both soluble EPS concentration and supernatant turbidity also showed the lowest value at the optimal dose. These foulants are believed to be coagulated and entrapped in sludge flocs during flocculation. Chitosan and MPE50 which are cationic polymeric substances showed higher reduction in both soluble EPS and fine particles comparing with ferric chloride.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.165-174
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• 2010

The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.2
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• pp.60-66
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• 2005

When external pressure higher than osmosis pressure is reversely derived into solution, its solvent is moved into the solution having lower concentration, which is called 'reverse osmosis'. We investigated the desalination application of deep ocean water using reverse osmosis pressure of $40-70\;kgf/cm^2$ We observed how to operational factor j like flow rate, water temperature and pressure have effect on efficiency of reverse osmosis membrane and salts rejection. Fluxes of reverse osmosis membrane are directly proportional to water temperature and pressure. However, salts rejection rates are positively correlated with pressure and inversely proportional to water temperature. Separation efficiencies of osmosis membrane for major elements such as $Mg^{2+},\;Ca^{+2},\;Na^+\;and\;K^+$ are as follows in a strong electrolysis solution like seawater; $Ca^{2+},\;Mg^{2+}>K^+>Na^+$. Rejection rates of $Mg^{2+}\;and\;Ca^{2+}$ that have high electric charges are over 99% and show positively correlation with water temperature. Rejection rates of $Na^+$ having low electric charge is observed to be 98%-99%, which rates is much lower than those of $2^+$ charged ions like $Ca^{2+}\;and\;Mg^{2+}$. Ion rejection rates of boron, B, are much low because boron is present il free state or gas phase in seawater. Boron concentration in desalination water is over criteria of Korean drinking water, 0.3 mg/L. However, we could satisfied with the criteria of drinking water under the operation condition like temperature $5^{\circ}C$ and pressure $70kgf/cm^2$, using the relationship that rejection rates of boron is proportional to pressure and is inversely proportional to water temperature

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.13-26
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• 1994

The present study was focused on investigation of proper processing conditions to develop physicochemical properties of extrudates using sea mustard and corn by single extruder. Response surface analysis was used to evaluate effects of extrusion variables on the quality of the extrudates. Physicochemical dependence variables of sea mustard extrudates with corn grits show a significance correlation of within $5\%$. Among the various dependence variables, the expansion ratio showed a high correlation with bulk density, break strength, water solubility index and yellowness. Bulk density correlated closely with water solubility index; break strength with water absorption index and lightness, and water absorption index with lightness. Water solubility index and lightness showed a significance correlation with yellowness of within $0.5\%$. Three dimensional graphic analysis on response surface regression was conducted with each of the dependent variables which revealed statistically significant relationship to independent variables: $15{\sim}21\%$ moisture content, $10{\sim}30\%$ sea mustard content and $95{\sim}115^{\circ}C$ die temperature. Expansion ratio decreased with increasing moisture and sea mustard content. It showed the highest value at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. and the lowest value was at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Bulk density was highest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. On the other hand, it was lowest at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. Break strength was highest at $18\%$ moisture content, $10\%$ sea mustard content and $115^{\circ}C$ die temperature, but lowest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Water solubility index increased in the range of $43.9{\sim}54.8\%$ as the moisture content increased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.203-213
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• 1991

Zooplankton samples were collected vertically from different layers with a closing net at 14 stations in the middle East Sea of Korea in February, August and September to study distribution of biological indicators for analysis of water masses. Horizontal and vertical distributions of important species of copepods and chaetognathas known as indicator species were closely related to distributions of different water masses and oceanic fronts. Pleuromamma gracilis, Calanus tenuicornis, Sagitta enflata and Sagitta minima were found to be reliable indicator species to determine warm water mass with warm core, and Calanus cristatus, Calanus tonsus and Sagitta elegans could be used as cold water species for evaluating the movement of cold current from North Korea, and Gaetanus armiger was deep sea water species. Therefore, it was found that North Korean Cold Current down to the south along the coast appeared to be significant in the surface around Chumunjin area, and from here towards the south the cold water containing S. elegans submerged under warm water with S. enflata which were about $2{\~}4^{\circ}C$ higher than that of the vicinity and reappeared near Chukpeon area in surface layer. In the layer between loom and 300m depths, distribution of Pleuromamma gracilis and Sagitta bedoti indicated that warm water mass and front zone influenced by the different water systems were formed in northwestern area off Ulreung-do. In $300{\~}500m$ layer, the proper cold water could be estimated to be present in the northwestern area off Ulreung-do throughout the survey period by the high abundance of Gaetanus armiger. In August, distributions of S. bedoti, S. enflata and S. minima were valuable index to find oceanic fronts and warm core.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.383-390
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• 1984

The present paper was carried out to elucidate the effect of salt-treatment and the addition of some food additives on the histamine formation and histidine decarboxylase activity in mackerel muscle during storage under different conditions. The histamine formation was inhibited by salting and histamine was hardly formed regardless of the brine concentraction during storage at $5^{\circ}C$. While, during storage at $25^{\circ}C$, the inhibitory effect upon the histamine formation and histidine decarboxylase activity was in proportion to the increase of the brine concentration. The addition of accidulants such as citric acid, malic acid and succinic acid inhibited the histamine formation and histidine decarboxylase activity. Especially, the histamine contents in the muscle added $10\%$ of citric acid and malic acid was below the critical concentration of poisoning for histamine during storage at $25^{\circ}C$ for 10 days. The histamine formation and histidine decarboxylase activity were inhibited by the $10\%$ addition of D-sorbitol, while there was no significant effect in the case of $5\%$ addition. Generally, the histamine content was increased with histidine decarboxylase activity, but didn't reveal the quantitative correlation ship with the enzyme activity.