• Economic and Environmental Geology
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• v.48 no.4
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• pp.337-349
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• 2015

This study has focused on investigation of correlation for As and heavy metals in paddy soil and rice crops sampled in the vicinity of the abandoned Munmyung Au-Ag mine. Soil samples extracted by various methods including aqua regia, 1 M $MgCl_2$, 0.01 M $CaCl_2$ and 0.05 M EDTA were analyzed for As and heavy metals (Cd, Cu, Pb and Zn). Rice grain samples grown on the soils were also analyzed for the same elements to evaluate the relationships between soils and rice crops. According to soil extraction methods, As and heavy metal contents in the soils were decreased in the order of aqua regia > 0.01 M $CaCl_2$ > 1 M $MgCl_2$ > 0.05 M EDTA. In addition to correlation analysis, statistically significant correlation with the four extraction methods (p<0.01) were found in the soil and rice samples. As calculation of biological accumulation coefficients (BACs) of the rice crops for As and heavy metals, the BACs for Cd, Zn and Cu were relatively higher than those for As and Pb. This study also carried out a stepwise multiple linear regression analysis to identify the dominant factors influencing metal extraction rates of the paddy soils. Furthermore, daily intakes of As and heavy metals from regularly consumed the rice grain (287 g/day) grown on the contaminated soils by the mining activities were estimated, and found that Cd and As intakes from the rice reached up to 73.7% and 51.8% for maximum allowance levels of trace elements suggested by WHO, respectively. Therefore, long-term consumption of the rice poses potential health problems to residents around the mine, although no adverse health effects have yet been observed.

• Journal of Mushroom
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• v.15 no.3
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• pp.124-128
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• 2017

The fruiting bodies of Sanghwang mushrooms, Phellinus linteus HN1009K (PLH) and Phellinus linteus (Korea Sanghwang, PLK), and Phellinus baumii (Jangsu Sangwhang, PB), were extracted with 70% methanol. The methanolic extracts of different concentrations ($5-200{\mu}g/ml$) showed inhibitory effects of 20-95% on plated aggregation induced by collagen (2.5 ug/ml), ADP (10 uM), and thrombin (0.1 U/ml). The PLH, PLK, and PB extracts (200 ug/ml) reduced ATP release from ADP-activated platelets by 50-60%. These results suggest that the methanolic extracts from Sanghwang mushrooms inhibit platelet aggregation.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.27-36
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• 2007

A recent study showed that MTBE can be degraded by Fenton's Reagent (FR). The treatment of MTBE with FR, however, has a definite limitation of extremely low pH requirement (optimum pH $3{\sim}4$) that makes the process impracticable under neutral pH condition on which the ferrous ion precipitate forming salt with hydroxyl anion, which result in the diminishment of the Fenton reaction and incompatible with biological treatment. Consequently, this process using only FR is not suitable for in-situ remediation of MTBE. In order to overcome this limitation, modified Fenton process using NTA, oxalate, and acetate as chelating reagents was introduced into this study. Modified Fenton reaction, available at near neutral pH, has been researched for the purpose of obtaining high performance of oxidation efficiency with stabilized ferrous or ferric ion by chelating agent. In the MTBE degradation experiment with modified Fenton reaction, it was observed that this reaction was influenced by some factors such as concentrations of ferric ion, hydrogen peroxide, and each chelating agent and pH. Six potential chelators including oxalate, succinate, acetate, citrate, NTA, and EDTA were tested to identify an appropriate chelator. Among them, oxalate, acetate, and NTA were selected based on their remediation efficiency and biodegradability of each chelator. Using NTA, the best result was obtained, showing more than 99.9% of MTBE degradation after 30 min at pH 7; the initial concentration of hydrogen peroxide, NTA, and ferric ion were 1470 mM, 6 mM, and 2 mM, respectively. Under the same experimental condition, the removal of MTBE using oxalate and acetate were 91.3% and 75.8%, respectively. Optimum concentration of iron ion were 3 mM using oxalate which showed the greatest removal efficiency. In case of acetate, $[MTBE]_0$ decreased gradually when concentration of iron ion increased above 5 mM. In this research, it was showed that modified Fenton reaction is proper for in-situ remediation of MTBE with great efficiency and the application of chelatimg agents, such as NTA, was able to make the ferric ion stable even at near neutral pH. In consequence, the outcomes of this study clearly showed that the modified Fenton process successfully coped with the limitation of the low pH requirement. Furthermore, the introduction of low molecular weight organic acids makes the process more available since these compounds have distinguishable biodegradability and it may be able to use natural iron mineral as catalyst for in situ remediation, so as to produce hydroxyl radical without the additional injection of ferric ion.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.243-248
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• 1998

Ark shell was known as shellfish that had hemoglobin as blood pigment and the action of mecidine, was consumed the great part of it as raw material, though it was produced about 13,000 M/T per year. Ark shell was processed the infinitesimal quantity as conned product, bout canned ark shell had problem that occurrenced discoloration after heat treatment during processing and storage. This discoloration mechanism during processing and storage was not cleared. This study was carried out to understand characteristics of the hemoglobin as blood pigment and carotenoid as meat pigment in ark shell and management of proper processing conditions for prevention of oxidation and discoloration by thermal treatment. When treated by digestion of 0.1% BHA, 0.1% Tenox-II, 0.5% Na2EDTA, 0.05% NDGA and 3% salt soln., 0.1% BHA solution was most suitable for stability of carotenoid that the retention ratio of carotenoids were 63.1% after heating to 116$^{\circ}C$ for 120 minutes. In preparation of canned ark shell and storage at 37$\pm$1$^{\circ}C$ for 60 days, the chemical composition, pH and salinity ere stable. And contents of total carotenoid were decreased slightly from 0.83mg% to 0.727mg%. The viable cell count were 6.92$\times$103 cfu/ml at raw ark shell, after processed and storage were not detected. The predominant amino acids in the raw ark shell were glutamic acid(19.7%), arginine(16.0%), glycine(12.6%), alanine(12.2%) and aspartic acid(7.6%). When 60 days stored, the contents of amino acid were stable. And the predominant nuclotide and their related compounds in the raw ark shell were hypoxanthine(2.14$\mu$mol/g), IMP(1.94$\mu$mol/g) and ATP(0.87$\mu$mol/g), and storage at 37$\pm$1$^{\circ}C$ for 60 days, the quantity order were same as raw material.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.116-128
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• 1999

치근흡수 연구에서 치아재식을 위한 적당한 동물모델을 찾는일은 대단히 중요하다. 본 실험에서는 쥐 대구치의 발치 및 재식을 통해서 치근흡수가 발현되는 모양을 관찰했다. 모두 20마리의 쥐(30일생)에게 0.4% ${\beta}$-APN(aminoproprionitrile)가 포함된 분말용쥐사료를 5일간 먹인후 케타민 마취후 상악좌우측 제일대구치를 손상을 최소화하여 발치 하였다. 발거된 쥐치아는 0.02M Tris-HCl로 표면처리하여 부착치근막을 제거한후 파라핀팍스로 치근단을 밀폐 하여 재식하였다. 재식후 1, 2, 4, 6, 8 및 12일이 경과된 후 심장관혈을 통하여 쥐를 희생시킨후 3% glutaraldehyde가 포함된 EDTA에서 탈회한후 Epon 포매 하였다. 모든 시편은 유리칼을 사용하여 1미크론 두께로 절편한후 veronal acetate buffer에 녹인 1% toluidine blue로 염색하였다. 파치세포양 세포에 의한 치근흡수는 재식 5-7일후 처음 관찰되었다. 재식 12일후에는 치근 전체에 걸친 광범위한 치근흡수가 관찰되었다. 이상의 결과 ${\beta}$-APN을 포함한 쥐사료 식이요법은 쥐 상악제일대구치의 발치와 재식을 용이하게 하여 일정한 치근흡수를 발현시키는데 많은 도움이 된 것으로 판단되었다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.257-257
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• 1994

생쥐의 장내세균으로 부터 황산전이 반응을 촉매하는 효소인 sulfotransferase를 생산하는 균주를 분리하였으며 동정결과 Haemophilus속 균주로 확인되어 Haemophilus K-12라 명명하였다. 균의 성장과 효소활성과의 관계를 보면 균은 10시간에서 완전히 성장하였으며 효소활성도 이와 비례하였다. Haemophilus K-12의 배지조성에 따른 sulfotransferase의 생산성을 Brain Heart Infusion 배지에서의 생산성과 비교해보면 탄소원으로는 sucrose가 0.2%농도에서 584%로 가장 좋았으며 질소원으로는 yeast extract가 266%로 가장 좋았다. 공여체로 PNS를 최종농도 1mM로 하여 배지에 첨가하였을때 212%로 가장 높은 효소증가를 보였다. 2가금속이온에 의한 효소증가는 현저하지 않았으며 $Mn^{2+}$이 107%로 가장 높았고$Zn^{2+}$와 EDTA에 의해서는 저해를 받았다. 이상의 결과를 종합하여 균배양을 위한 이상적인 배지조성을 sucrose 0.2%, yeast extract 1%, $Na_2$HPO$_4$ 0.25%, NaCl 0.5%로 결정하였다. 결정된 최적배지에 균을 10L 배양하여 초음파 처리, 원심분리한 것을 70 % ammonium sulfate fractionation, DEAE-cellulose column chromatography를 2회, Hydroxyapatite column chromatography, chromatdfocusing column chromatography, Silica PAE column chromatography, Sephacryl S-300 superfine column chromatography를 행한결과 specific activity가 6.76 umoie/min/mg protein인 효소액을 얻었으며 homogeneous enzyme였다. 이렇게 해서 얻은 효소를 이용하여 수용체 기질 특이성을 측정한 결과 1-naphthol이 phenol을 100%로 하였을 때 233%로 가장 좋았으며 Eubacterium A-44 sulfotransferase의 좋은 기질이었던 p-acetaminophenol, tyramine, 9-phenanthrol은 좋은 기질이 되지 못했다. 이상의 결과로 미루어 보아Haemophilus K-12 sulfotransferase는 지금까지 보고된 bacterial sulfotrasferase와는 다른 효소로 사려되며 효소반응기전의 규명이 이루어지면 산업적 응용이 가능할것으로 사료된다.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.243-251
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• 2010

Nitrogen oxides (NOx) in combustion flue gas are currently mitigated by chemical processes such as catalytic reduction, absorption and adsorption. However, development of environmentally sustainable biological processes is necessary in the near future. In this paper, the up-to-dated R&D trend of biological methodologies regarding NOx removal was reviewed, and their advantages and disadvantages were discussed. The principles and applications of bacterial system including nitrification and denitrification and photosynthetic microalgae system were compared. In order to enhance biological treatment rate and performance, the insoluble nitric oxide (NO) should be first absorbed using a proper solubilization agent, and then microbial degradation or fixation is to be followed. The use of microalgal system has a good prospect because it can fix $CO_2$ and NOx simultaneously and requires no additional carbon for energy source.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.163-169
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• 2012

We have conducted three experiments to develop a fertilizer-dissolving apparatus used in fertigation or hydroponics cultivation in order to decrease the fertilizer dissolving time and labor input via automation. All of the experiments were conducted twice. In the first experiment, four selected treatments were tested to dissolve fertilizers rapidly. The first treatment was to dissolve fertilizer by spraying water with a submerged water pump, placed in the nutrient solution tank. The water was sprayed onto fertilizer, which is dissolved and filtered through the hemp cloth mounted on the upper part of the nutrient solution tank (Spray). The second treatment was to install a propeller on the bottom of the nutrient solution tank (Propeller). The third treatment was to produce a water stream with a submerged water pump, located at the bottom of the tank (Submerged). Finally, the fourth treatment was to produce an air stream through air pipes with an air compressor located at the bottom of the tank (Airflow). The Spray treatment was found to take the shortest time to dissolve fertilizer, yet it was inconvenient to implement and manage after installation. The Airflow treatment was thought to be the best method in terms of the time to dissolve, labor input, and automation. In the second experiment, Airflow treatment was investigated in more detail. In order to determine the optimal number of air pipe arms and their specification, different versions of 6- and 8-arm air pipe systems were evaluated. The apparatus with 6 arms (Arm-6) that was made of light density polyethylene was determined to be the best system, evaluated on its time to dissolve fertilizer, easiness to use regardless of the lid size of the tank, and easiness to produce and install. In the third experiment, the Submerged and Arm-6 treatments were compared for their dissolving time and economics. Arm-6 treatment decreased the dissolving time by 8 times and proved to be very economic. In addition, dissolving characteristics were investigated for $KNO_3$, $Ca(NO_3)_2{\cdot}4H_2O$, and Fe-EDTA.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.35-43
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• 2005

Bioslurping combines the three remedial approaches of bioventing, vacuum-enhanced free-product recovery, and soil vapor extraction. Bioslurping is less effective in tight (low-permeability) soils. The greatest limitation to air permeability is excessive soil moisture. Optimum soil moisture is very soil-specific. Too much moisture can reduce air permeability of the soil and decrease its oxygen transfer capability. Too little moisture will inhibit microbial activity. So Modified Fenton reaction as chemical treatment which can overcome the weakness of Bioslurping was experimented for simultaneous treatment. Although the diesel removal efficiency of SVE process increased in proportion to applied vacuum pressure, SVE process was difficulty to remediation quickly semi- or non-volatile compounds absorbed soil strongly. And SVE process had variation of efficiency with distance from the extraction well and depth a air flow form of hemisphere centering around the well. Below 0.1 % hydrogen peroxide shows the potential of using hydrogen peroxide as oxygen source but the co-oxidation of chemical and biological treatment was impossible because of the low efficiency of Modified Fenton reaction at 0.1 % (wt) hydrogen peroxide. NTA was more efficiency than EDTA as chelating agent and diesel removal efficiency of Modified Fenton reaction increased in proportion to hydrogen peroxide concentration. Hexadecane as typical aliphatic compound was removed less than Toluene as aromatic compound because of its structural stability in Modified Fenton reaction. What minimum 10% hydrogen peroxide concentration has good remediation efficiency of diesel contaminated groundwater may show the potential use of Modified Fenton reaction after bioslurping treatment.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.197-206
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• 1990

Various conditions of cultures were performed to investigate the role of tight junctions formed between adjacent MDCK cells on the entry of Toxoplasma. When MDCK cells were cocultured with excess number of Toxoplasma at the seeding density of 1×105, 3×105, and 5×105 cells/ml for 4 days, the number of intracellular parasites decreased rapidly as the host cells reached saturation density, i.e., the formation of tight junctions. When the concentration of calcium in the media (1.8 mM in general) was shifted to $5{\mu}M$ that resulted in the elimination of tight junction, the penetration of Toxoplasma increased about 2-fold(p<0.05) in the saturated culture, while that of non-saturated culture decreased by half. Trypsin-EDTA which was treated to conquer the tight junctions of saturated culture favored the entry of Toxoplasma about 2.5-fold(P<0.05) compared to the non-treated, while that of non- saturated culture decreased to about one fifth. It was suggested that the tight junctions of epithelial cells play a role as a barrier for the entry of Toxoplasma and Toxoplasma penetrate into hoot cells through membrane structure-specific, i.e., certain kind of receptors present on the basolateral rather than apical surface of MDCK cells.