• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.675-687
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• 2005

In this study, the cyclone/denuder/filter pack sampling system was used to measure the daily concentrations of water soluble inorganic compounds of fine ($D_{p}< 2.5\;{\mu}m$) and coarse ($D_{p}<10{\mu}m$m) size fractions of aerosol and related gases at Gosan super site during ABC-EAREX 2005. The mean concentrations for $HNO_{3},\;HNO_{2},\;NH_{3}$, were 0.39, 0.08, and $0.29\;{\mu}g/m^3$. respectively. Average concentrations of sulfate, nitrate, and ammonium in $PM_{2.5}$ were 3.39, 1.06, and $1.04\;{\mu}g/m^3$, which occupied about $26\%$ of total $PM_{2.5}$ mass. In particular, more than half of these ionic species were found in size of less than $2.5\;{\mu}m$. Gas phase nitric acid concentrations have shown high correlation coefficient with $HNO_{2}$(R=0.80) and $O_{3}$(R=0.78), implying the active photochemical reactions from its precursors. Equivalent molar ratios between major ion components, $NH_{4}\;^{+}/nss\;SO_4\;^{2-},(0.83\;for\;PM_{2.5},\;0.86\;for\;PM_{10})$, revealed that the existing forms of the secondary aerosols were probably $(NH_{4})_{2}SO_{4}\;and\;(NH_{4})_{3}H\;(SO_{4})_{2}$. Especially, $(NH_{4}\;^{+}+K^{+}+Ca^{2+}+Mg^{2+})/(NO_{3}\;^{-}+nss\;SO_{4}\;^{2-}) (0.99\;for\;PM_{2.5},\;1.05\;for\;PM_{10})$ indicated that some of them existed not only as $NH_{4}NO_{3}$ but also as $CaSO_{4}\;or\;KNO_{3}$, which pointed out the probability of influences from the abundant soil components during Asian dust (AD) periods. These neutralized types of secondary aerosols showed that pollutants could be aged and transported from a distance.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.252-261
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• 2008

Two experiments were conducted to compare the effects of feeding organic acids and antibiotic growth promoters in weaned pigs. In Exp. 1, 96 nursery pigs (Large White$\times$Landrace; initial weight $7.80{\pm}0.07kg$) were randomly allotted into one of four dietary treatments. Pigs in treatment 1 were fed a complex starter diet. Treatments 2 to 4 were the same as treatment 1 but supplemented with antibiotics (200 ppm chlortetracycline plus 60 ppm Lincospectin), 0.5% potassium diformate or 0.5% dry organic acid blend ACTIVATE Starter DA (ASD). During the 4-week post-weaning period, pigs fed ASD or antibiotics had better gain (p = 0.03) and feed efficiency (p = 0.04) than pigs fed the control diet. On d 14 post-weaning, pigs fed the control diet had the lowest fecal lactobacilli count among all dietary treatments (p = 0.02), whereas pigs fed ASD or antibiotics had a trend for lower fecal E. coli count compared to the control pigs (p = 0.08). Serum insulin-like growth factor-1 (IGF-1) of pigs fed ASD did not differ from pigs fed the control diet (p>0.05) at d 14 after weaning. In Exp. 2, 24 weaned pigs (Large White$\times$Long White; initial weight $5.94{\pm}0.33kg$) were allotted into four groups and housed individually. Pigs were fed a control diet or diets supplemented with antibiotics (100 ppm colistin sulfate, 50 ppm Kitasamycin plus 60 ppm Olaquindox), 0.5% or 1% ASD. All pigs were orally challenged with E. coli $K88^+$ on d 5. During d 5 to 14 after challenge, pigs fed antibiotics, 0.5% or 1% ASD had better gain (p = 0.01) and feed efficiency (p = 0.03) than pigs fed the control diet. On d 14, compared to the control pigs, pigs fed 0.5% ASD had higher lactobacilli in the duodenum and pigs fed 1% ASD and antibiotics had a trend for higher lactobacilli in the ileum (p = 0.08). Pigs fed antibiotics, 0.5% or 1% ASD diets tended to have decreased ileal E. coli count compared to those fed the control diet (p = 0.08). Serum interleukin-6 and cortisol and digesta pH values were not affected by treatment or time. These results indicate that feeding ASD can improve the growth performance of weaning pigs, mainly via modulating intestinal microflora populations without affecting gastrointestinal pH or immune indices.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.999-1006
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• 2015

The endo-polygalacturonase gene (endo-pgaA) was cloned from DNA of Aspergillus niger SC323 using the cDNA synthesized by overlapping PCR, and successfully expressed in Saccharomyces cerevisiae EBY100 through fusing the α-factor signal peptide of yeast. The fulllength cDNA consists of 1,113 bp and encodes a protein of 370 amino acids with a calculated molecular mass of 38.8 kDa. After induction by galactose for 48 h, the activity of recombinant endo-PgaA in the culture supernatant can reach up to 1,448.48 U/mg. The recombinant protein was purified to homogeneity by ammonium sulfate precipitation and gel filtration column chromatography and subsequently characterized. The optimal pH and temperature of the purified recombinant enzyme were 5.0 and 50℃, respectively. The Michaelis-Menten constant (K_m) and maximal velocity (V_max) of the enzyme for pectin were 88.54 μmol/ml and 175.44 μmol/mg/min, respectively. The enzyme activity was enhanced by Ca²⁺, Cu²⁺, and Na⁺, and strongly inhibited by Pb²⁺ and Mn²⁺. The pectin hydrolysates were mainly galacturonic acid and other oligo-galacturonates. Therefore, these characteristics suggest that the recombinant endo-PgaA may be of potential use in the food and feed industries.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.565-573
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• 2000

Sewer pipe in Korea is generally constructed with concrete pipes. Moreover, the sewer system is susceptible to the corrosion problem due to the regulation employing anaerobic treatment processes, such as domestic sewage treatment facilities, nightsoil septic tanks and so on. The objective of this study is investigated to experimental test of $H_2S$ production rate affecting corrosion of sewer pipe in Korea. In this study, tube-type and sealed-type reactor were used to examine the reactions in the microorganism suspended growth and biofilm. Furthermore. concentration changes were investigated with COD and sulfate reduction in each reactor. Sulfide production rate was $50.4mg-H_2S/g-VSS{\cdot}d$ in the sealed-type reactor and in the tube-type biofilm reactor was $2.8{\sim}18.8g-H_2S/m^2{\cdot}d$.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1777-1787
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• 2000

The purpose of this study was to select an effective and economical alkali source for sulfur-utilizing autotrophic denitrification. Tests on acid neutralization and denitrification at various alkali/sulfur mixing ratios were performed for charcoal, briquette ashes, sea shell, and limestone. The results of the experiments showed that sea shell was the most effective alkali source because it could provide more surface area than limestone, and the optimal alkali/sulfur mixing ratio was 1/1(V/V). In a sulfur/sea shell packed bed reactor, the denitrification efficiency was above 90% up to a loading rate of 116 g $NO_3{^-}-N/m^3-day$. but the denitrification efficiency deteriorated to 48% at the loading rate of 145 g $NO_3{^-}-N/m^3-day$. The average $SO_4{^{2-}}$ generation per g of $NO_3{^-}-N$ removed was 7.02 g, which is lower than the theoretical value of 7.54 g. Denitrification and sulfate generation appeared to be a first-order and a zero-order reaction with a reaction rate constant of 0.146 /hr and -53.1 mg/L-hr, respectively. According to nitrogen mass balance, 71~109%, with an average of 90%, of the removed nitrogen was recovered as $N_2$ gas.

• The Korean Journal of Mycology
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• v.8 no.3
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• pp.133-142
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• 1980

Poria cocos, a parasite on Pinus densiflora was studied for its optimum growing condition from May 1, 1979 to November 15, 1980. 1) The optimum pH value was 5.0, and it had poor growth below pH 3.0 and no growth above pH 7.0. 2) The optimum temperatures were $25{\sim}27^{\circ}C$, and it had poor growth below $5^{\circ}C$. 3) On Robbins and Herrey's solid media, malt extract(diameter of colony at 2% of the above material was 90mm) and tomato extract(at 8% was 90mm) gave the best growth. 4) By Badcock method, the best growth was obtained in P.D.A. supplemented with accelerator 5% of the above material of liquid media(85mm in diameter of colony) and malt extract 2% of P.D.A. added with accelerator 5% of them of liquid media(410mg of hyphae of dry weight) but the growth rate was poor in the media of wood extract agar supplemented with accelerator 5% of the above material giving 30mm diameter of the colony. 5) The growth on Robbins basal medium supplemented with Quercus accutissima extract showed 305. 3mg of hyphae of dry weight and Robinia pseudoacasia was supplemented with it showed 256.3mg of them. 6) The best growth was obtained in Jennison basal medium supplemented with L-asparagine showing 44.3mg of hyphae of dry weight.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.60-66
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• 1996

Bradyrhizobium japonicum with different colony morphology populated in five Yeongnam soils of Korea was examined for intrinsic antibiotic resistance to eight antibiotics, serological property by immunoblot and immunodiffusion, and protein profile differentiation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Colony morphological distribution of one hundred and twenty B. japonicum isolates was 47% for "dry". 41% for "wet", and 12% for "dry/wet" type. The total isolates showed such a strong correlation between the morphology and antibiotic resistance. Colony morphology, which though was dominantly consisted of the same type within a serogroup, wasn't absolutely linked to serological property of B. japonicum. Based on these data, colony morphology was too simple to identify variations with B. japonicum isolates : antibiotic resistance such complicated compared with serological analyses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.659-666
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• 1995

Fucoidans were isolated from Hizikia fusiformis and Sargassum fulvellum and characterized on their chemical properties. Crude fucoidans were extracted at $65^{\circ}C$ for 1hr with acid solution of pH 2.0, and cetylpyridinum chloride was used for partial purification. The yields of partially purified fucoidans were $2.51\%$ for H. fusiformis, and $65\%$ for S. fulvellum, respectively. The partially purified fucoidans were separated into 3 fractions by DEAE-Sephadex A-25 ion exchange column chromatography and the major fractions were refractionated with fractional preripitation with ethanol. $60-70\%$ ethanol precipitated fraction(P-70) of H. fusiformis and $60-65\%$ ethanol precipitated fraction(P-65) of S. fulvellum turned out to be homogeneous by cellulose acetate electrophoresis and gel filtration chromatography. The molar ratios of fucose, galactose, and sulfate In the purified fucoidans were 1 : 0.66 2.74 for H. fusiformis and 1 : 0.24. 1.46 for 5. fulvellum. The averaged molecular weights of the purified fucoidans from H. fusiformis and S. fulvellum were 26,000 and 105,000, respectively.

• Journal of the Mineralogical Society of Korea
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• v.27 no.3
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• pp.115-124
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• 2014

In order to leach Au and Ag from gold-silver bearing sulfide concentrate, the sulfide concentrate was ground in a ball mill for a dry pre-treatment and a wet pre-treatment process. Mineralogical studies and thiourea leaching experiments were carried out with the pre-treated sulfide concentrate. The results of the pre-treatment with the concentrate samples showed the mean particle size and iso-electrical potential was smaller in the dry pre-treatment sample than in the concentrate sample, and the contents was lower in the wet pre-treatment sample than in the dry pre-treatment sample. In XRD analysis, amorphous properties were only shown in the wet pretreatment sample. The results of the concentrate sample leaching experiments showed that the best Au, Ag leaching parameters were when the addition of thiourea was at a 1.0 g concentration, ferric sulfate was 1.0 M, sulfuric acid was 2.0 M and the leaching temperature was at $60^{\circ}C$. The Au, Ag leaching rate was always much greater and faster with the wet pre-treatment samples than with the dry pre-treatment samples. Accordingly, it is expected that more Au, Ag can be leached in an eco-friendly methodology using wet pre-treatment. The pre-treatment could be improved with an optimized grinding additive reagent and through researching grinding time in future non-cyanide processes.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.1
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• pp.31-42
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• 2000

The dry deposition velocities and fluxes of air pollutants such as SO2(g), O3(g), HNO3(g), sub-micron particulates, NO3(s), and SO42-(s) were estimated according to local meteorological elements in the atmospheric boundary layer. The model used for these calculations was the multiple layer resistance model developed by Hicks et al.1). The meteorological data were recorded on an hourly basis from July, 1990 to June, 1991 at the Austin Cary forest site, near Gainesville FL. Weekly integrated samples of ambient dry deposition species were collected at the site using triple-fiter packs. For the study period, the annual average dry deposition velocities at this site were estimated as 0.87$\pm$0.07 cm/s for SO2(g), 0.65$\pm$0.11 cm/s for O3(g), 1.20$\pm$0.14cm/s for HNO3(g), 0.0045$\pm$0.0006 cm/s for sub-micron particulates, and 0.089$\pm$0.014 cm/s for NO3-(s) and SO42-(s). The trends observed in the daily mean deposition velocities were largely seasonal, indicated by larger deposition velocities for the summer season and smaller deposition velocities for the winter season. The monthly and weekly averaged values for the deposition velocities did not show large differences over the year yet did show a tendency of increased deposition velocities in the summer and decreased values in the winter. The annual mean concentrations of the air pollutants obtained by the triple filter pack every 7 days were 3.63$\pm$1.92 $\mu\textrm{g}$/m3 for SO42-, 2.00$\pm$1.22 $\mu\textrm{g}$/m-3 for SO2, 1.30$\pm$0.59 $\mu\textrm{g}$/m-3 for HNO3, and 0.704$\pm$0.419 $\mu\textrm{g}$/m3 for NO3-, respectively. The air pollutant with the largest deposition flux was SO2 followed by HNO3, SO42-(S), and NO3-(S) in order of their magnitude. The sulfur dioxide and NO3- deposition fluxes were higher in the winter than in the summer, and the nitric acid and sulfate deposition fluxes were high during the spring and summer.