• Korean Journal of Metals and Materials
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• v.49 no.12
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• pp.956-966
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• 2011

Bioleaching studies of metals from a spent catalyst were conducted using both adapted and unadapted bacterial cultures. The bacterium used in this experiment was Acidithiobacillus ferrooxidans. A comparison of the kinetics of leaching was made between the two cultures by varying the leaching parameters, including the pulp density, particle size and temperature. Both cultures showed similar effects with respect to the above parameters, but the leaching rates of all metals were higher with the adapted compared to the unadapted bacterial cultures. The leaching reactions were continued for 240 h in the case of the unadapted bacterial culture, but only for 40 h in the case of the adapted bacterial culture. The leaching reactions followed first order kinetics. In addition, the kinetics of leaching was concluded to be a diffusion control model; therefore, the product layers were impervious.

• Journal of Pharmacopuncture
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• v.10 no.3
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• pp.71-76
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• 2007

Objectives This experimental study was performed to investigate the continuous anti-bacterial potency of Coptidis rhizoma extract on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods Minimal inhibitory concentration(MIC) was measured by dropping to $50{\mu}l$ diluted Coptidis rhizoma extract(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume($20{\mu}l,\;30{\mu}l,\;40{\mu}l,\;50{\mu}l$). Results 1. Anti-bacterial potency of Coptidis rhizoma extract on S. aureus was appeared in 100%, 10% and was the same as anti-bacterial potency of 2 days and 6 days. Anti-bacterial potency with change of volume(100%) was increased in propotion to increase volume on all samples. Anti-bacterial potency with change of volume(10%) was increased in propotion to increase volume on all samples except $20{\mu}l$. Anti-bacterial potency of Coptidis rhizoma extract on S. aureus was appeared continuous. 2. Anti-bacterial potency of Coptidis rhizoma extract on S. epidermidis was appeared in 100%, 10% and was the same as anti-bacterial potency of 2 days and 6 days. Anti-bacterial potency with change of volume(100%) was increased in propotion to increase volume on all samples. Anti-bacterial potency with change of volume(10%) was appeared in $50{\mu}l$. Anti-bacterial potency of Coptidis rhizoma extract on S. epidermidis was appeared continuous. Conclusions Anti-bacterial potency of Coptidis rhizoma extract on cultivation of S. aureus & S. epidermidis was showed continuous.

• Journal of Pharmacopuncture
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• v.10 no.2 s.23
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• pp.67-71
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Tangpo-san on cultivation of Staphylococcus species(S. aureus, S. epidermidis)that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50 ${\mu}$l diluted Tangpo-san(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20 ${\mu}$l,30 ${\mu}$l,40 ${\mu}$l,50 ${\mu}$l). Results : 1. Anti-bacterial potency of Tanpo-san on S. aureus was not appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume, and the Anti-bacterial potency of 2 days was equal to 6 days. Anti-bacterial potency of Tangpo-san on S. aureus was appeared continuous. 2. Anti-bacterial potency of Tangpo-san on S. epidermidis was appeared in 100%, 10% on 2 and 6 days, and the Anti-bacterial potency of 6 days was decreased. In 2 days, Anti-bacterial potency was appeared 40 and 50u1, in 6 days, Anti-bacterial potency was appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency of Tangpo-san on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Tangpo-san on cultivation of S. aureus showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.77-84
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• 2009

Using recombinant DNA technology, the vector system containing minimal fragment of a bacterial hemoglobin gene (vgb) was constructed. When this vector was inserted into Escherichia coli, the growth of the host was significantly improved in both viable cell counts and absorbance measurement, compared to that of the wild type strain. In addition, by minimizing the size of bacterial hemoglobin in the vector, the ability of vgb in growth improvement was augmented, due to the reduction of metabolic burden from the maintenance and replication of the plasmid. By using this system, it is expected that the growth of microorganisms can be improved even in the hypoxic condition.

• Journal of Pharmacopuncture
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• v.10 no.2 s.23
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• pp.87-91
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Jinpi-san on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50${\mu}$l diluted Jinpi-san(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20${\mu}$l, 30${\mu}$l, 40${\mu}$l, 50${\mu}$l). Results : 1. Anti-bacterial potency of Jinpi-san on S. aureus was appeared in 100% and increased on 6 days. Anti-bacterial potency with change of volume was increased in propotion to increase volume. Anti-bacterial potency of Jinpi-san on S. aureus was appeared continuous. 2. Anti-bacterial potency of Jinpi-san on S. epidermidis was appeared in 100%, 10%, 1% on 2 days and in 100%, 10% on 6 days. In 100% Jinpi-san, Anti-bacterial potency of 6 days was increased, in 10%, Anti-bacterial potency of 2 days was increased, in 1%, Anti-bacterial potency of 6 days was disappear. Anti-bacterial potency with change of volume was increased in propotion to increase volume except for 20${\mu}$l of 6days and increased on 6 days, but bacteria was increased. Anti-bacterial potency of Jinpi-san on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Jinpi-san on cultivation of S. aureus was showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1320-1332
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• 2016

Light hydrocarbons accumulated in subsurface soil by long-term microseepage could favor the anomalous growth of indigenous hydrocarbon-oxidizing microorganisms, which could be crucial indicators of underlying petroleum reservoirs. Here, Illumina MiSeq sequencing of the 16S rRNA gene was conducted to determine the bacterial community structures in soil samples collected from three typical oil and gas fields at different locations in China. Incubation with n-butane at the laboratory scale was performed to confirm the presence of "universal microbes" in light-hydrocarbon microseepage ecosystems. The results indicated significantly higher bacterial diversity in next-to-well samples compared with background samples at two of the three sites, which were notably different to oil-contaminated environments. Variation partitioning analysis showed that the bacterial community structures above the oil and gas fields at the scale of the present study were shaped mainly by environmental parameters, and geographic location was able to explain only 7.05% of the variation independently. The linear discriminant analysis effect size method revealed that the oil and gas fields significantly favored the growth of Mycobacterium, Flavobacterium, and Pseudomonas, as well as other related bacteria. The relative abundance of Mycobacterium and Pseudomonas increased notably after n-butane cultivation, which highlighted their potential as biomarkers of underlying oil deposits. This work contributes to a broader perspective on the bacterial community structures shaped by long-term light-hydrocarbon microseepage and proposes relatively universal indicators, providing an additional resource for the improvement of microbial prospecting of oil and gas.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.53-62
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• 2019

Heterotrophic bacteria are a major member of the microbial loop in the marine ecosystem and play an important role in the biogeochemical cycle decomposing organic matter. Therefore study of bacterial variation is important to understand the material cycle and energy flow of marine ecosystems. We investigated the monthly variations of bacteria and environmental factors in the Youngsan River estuary, and the correlation between bacteria and phytoplankton biomass (chlorophyll-a) including size-structure. As a result, bacteria of the Youngsan River estuary were higher in the surface than in the bottom layer, and higher in the summer than in winter. And the closer to the dike, the abundance increased, and it increased to the peaks in August, September, and June 2019 at the station closest to the dike. The chlorophyll-a also increases at the stations and time when the bacterial abundance was high and they correlates positively displaying no difference between size fractions. The results indicate that organic matter derived from phytoplankton has an effect on bacterial variation but no size-dependent effects. In addition, the seasonal pattern of bacteria increasing in proportion to the water temperature suggests the effect of water temperature on the growth of bacteria. No association of bacterial abundance variation with nutrient supply due to freshwater input was observed. In this study, dissolved oxygen was depleted and hypoxia was observed for a short time when a strong stratification was not developed. This may be resulted from the supply of organic matter from phytoplankton and the consumption of oxygen due to bacterial decomposition.

• Journal of Pharmacopuncture
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• v.10 no.2 s.23
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• pp.19-23
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Sean-tang on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50${\mu}$l diluted Sean-tang(100%, 10%,1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. 1. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20${\mu}$l, 30${\mu}$l, 40${\mu}$l, 50${\mu}$l). Results : 1. Anti-bacterial potency of Sean-tang on S. aureus was appeared in 100% and increased on 6 days. Anti-bacterial potency with change of volume was increased in propotion to increase volume. Anti-bacterial potency of Sean-tang on S. aureus was appeared continuous. 2. Anti-bacterial potency of S. epidermidis was appeared in 100%, 10%, 1% on 2 days and in100%, 10% on 6 days. In 100% Sean-tang, Anti-bacterial potency of 6 days was increased, in 10%, 1%, Anti-bacterial potency of 2 days was increased. Anti-bacterial potency with change of volume was increased inpropotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency Sean-tang on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Sean-tang on cultivation of S. aureus was showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.35-40
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• 1999

Effects of different molecular size fractions (100,000 nMW-0.1 $\mu\textrm{m}$m, 10,000 nMW-100,000 nMW and 1,000 nMW-'L0,000 nMW) of dissolved organic matter on the bacterial numbers and $\beta$-glucosidase activities in Lake Soyang were investigated. Even though the concentrations and characteristics of each fractions were different, bacterial growth curves of each fractioii were Lypical and similar. Each growth curve had highest peak of $1.1{\times}10^{7}$ cells $ml^{-1}$. But, the $\beta$-lucosidase activitics of each fraction were quite different. In high molecular weight fraction (HMW: 100,000 nMW-0.1 $\mu\textrm{m}$m), Vmax of Pglucosidase activity ranged from 550 to 1,160 nmol $1^{-1}$.$hi^{-1}$, but in low molecular weight f~action (1,000 nMW-10,000 nMW), that ranged from 1 to 14 om01 1$^[-1}$${-1}$

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.376-376
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• 2016

Poly(ethylene oxide) (PEO)/functionalized bacterial cellulose nanowhiskers (f-BCNW) (0.1 wt%) composite nanofibers were fabricated by electrospinning process and the thermomechanical properties were significantly enhanced more than the PEO and PEO/bacterial cellulose nanowhiskers (BCNW) (0.1 wt%) composite nanofibers. The functionalization of BCNW (f-BCNW) was performed by microwave plasma treatment for effects of nitrogen functionalization of chemically-driven BCNW. The N-containing functional groups of f-BCNW enhanced chemical bonding between the hydroxyl groups of the polymer chains in the PEO matrix and diameter size of PEO/f-BCNW (0.1 wt%) composite nanofibers were decreased more than PEO and PEO/BCNW (0.1 wt%) composite nanofibers on the same concentration. The strong interfacial interactions between the f-BCNW nanofillers and polymer matrix were improved the thermomechanical properties such as crystallization temperature, weight loss and glass transition temperature (Tg) compared to PEO and PEO/BCNW composites nanofibers. The results demonstrated that N2 plasma treatment of BCNW is very useful in improving thermal stability for bio-applications.