• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.183-191
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• 2008

The effect of silver ion solution on the growth of Microcystis aeruginosa UTEX 2388 (cyanobacterium) and Chlorella sp. KCTC AG20136 (green alga) was investigated using separated and mixed culture in filtered natural water and BG11 medium. In separated culture, M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 were found to be sensitive to 0.01 and 0.1 mg L$^{-1}$ of silver ion, respectively. Also, the silver ion concentrations for the growth inhibition of M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 in the mixed culture were same in separated culture. Cyanobacteria were more sensitive to the silver ion solution than green algae. In bloom sample, the minimal inhibition concentration of silver ion solution for the low Chl-${\alpha}$ sample (110$\sim$190 ${\mu}g$ L$^{-1}$) and high Chl-${\alpha}$ sample (1,500$\sim$1,900 ${\mu}g$ L$^{-1}$) was about 0.1 and 3.0 mg L$^{-1}$, respectively. The silver ion concentration for the inhibition of algal bloom sample was affected by the algal biomass. In order to use silver ion solution for the control of algal bloom, the silver ion concentration must be determined in consideration of a minimal effect on the environment.

• The Plant Pathology Journal
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• v.28 no.1
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• pp.68-74
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• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.833-839
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• 2020

Globally, infection prevention and social awareness have been greatly changed by the severe acute respiratory syndrome coronavirus, and as a result, the infection control guidelines and procedures for patients with high exposure to hospital-acquired infection are further strengthened and management and monitoring are more thorough. In order to prevent infection, sterilization should be carried out with the highest priority, and we will find a sterilization method that is low in cost, easy to install, and easy to operate, to present appropriate sterilization effects. In this study, the UV sterilizer was used to contaminate the caries bacteria with an output of 4 W and irradiation time of 60, 150, and 300 sec, and the laser was irradiated with outputs of 0.8 and 1.5 W at wavelengths of 266 and 355 nm, respectively. Ultraviolet sterilizer showed safety in infection prevention at over 150 sec, and laser showed safety in prevention at 1.5 W, 0.8 W, and 266 nm. As a result, the higher the output and the wavelength closer to 253.7 nm, the better the sterilization effect.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.525-530
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• 1989

In order to enumerate the T-lymphocytes in bovine peripheral blood lymphocytes (PBL) by E rosette assay, KGRBC were treated with various concentrations of 2-aminoethylisothiouronium bromide(AET) and dextran(Dex), singly or in combination. To further standardize the assay, optimum concentration of AET- and/or Dex-treatment and incubation time for rosette forming cell(RFC) counts were determined. The levels of B-lymphocytes in the PBL were evaluated by erythzocyte-antibody($EA_{Fc}$)- and erythrocyte-antibody-complement (EAC)-rosetting techniques. The results obtained were as follows; The PBL from 20 clinically normal Korean cattle were formed as low percentage of spontaneous E-rosette ($6.7{\pm}2.4%$) in control group, whereas in KGRBC treated with 0.1M AET for 20 minutes and 8% Dex were formed as $37.3{\pm}2.7%$ and $45.1{\pm}2.1%$, respectively. And the synergistic effects were noted no less than $66.5{\pm}5.6%$ when the KGRBC treated with 0.1M AET and 8% Dex subsequently and rate of RFR did not change significantly between 3~24 hours incubation time at $4^{\circ}C$, EA-and EAC-RFR were $23.3{\pm}9.1%$ and $23.1{\pm}7.9%$, respectively. These results suggest that the KGRBC would be a useful agent for the enumeration of T-lymphocytes by E rosette assay and B-lymphocytes by EA- or EAC-rosette assay in cattle-PBL.

• KSBB Journal
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• v.14 no.3
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• pp.337-341
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• 1999

In order to investigate effects of loess on the mycelial pellet formation a phosphate dissolving fungus, Penicillium sp. GL-101, was cultured in potato dextrose broth containing loess. The strain formed an amorphous pellet or loose aggregates agitated at a low speed(50rpm) while spherical and regular pellets at a high speed(150rpm). The higher concentration of loess, the smaller size of a pellet in the medium formed by the strain. Cultured in the medium supplemented with 1.5% loess the pellet size was reduced to a seventh compared to the control. In the case of addition of several insoluble salts, which are main components of loess, to the culture medium the higher concentrations of salts, the smaller sizes of pellet formed by the strain and the smallest pellet was formed by the addition of calcium sulfate.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.140-148
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• 2009

MOV(Main Oxidizer shut-off Valves) control the combustion of launch vehicle systems by the supply and the isolation of liquid oxygen to a main combustion chamber in launch vehicle systems. Moreover, in the steady operational state, the MOV should secure a constant flow rate of liquid oxygen for combustion instability in the combustion chamber. Concerning the development of MOV, TM(Technology Model) has been manufactured and normal operations of the valve have been verified. However, the Cv of TM has been proved to be too low as compared with a design specification value. Therefore, CFD analysis have been performed by modification of the configurations of TM in order to increase sufficiently Cv of EM(Engineering Model), which is the following model of TM. The modifications of TM configurations such as partial scale-up of valve, increase of stroke length, and outlet angle of 120o would result in a considerable augmentation of Cv. It has been verified by flow capacity tests that the improved Cv of EM is min. 212, which is higher than Cv of TM, 161 by about 32%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.111-119
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• 1976

Discoloration of canned boiled oyster namely greening, yellowing and browning often occur separately or associatively in the storage of the product. Greening is mainly caused by the appearance of chlorophyll and its derivatives on the surface around the digestive diverticula of the oyster and yellowing by dispersion of carotenoid. Browning reactions by sugar amino condensation or enzymatic action, tyrosinase, also cause an undesirable color development. In this paper, the stability and the changes in distributional or partitional ratio of chlorophyll and carotenoid pigment of meat vs viscera in raw and canned oyster during six month storage in order to measure the dispersion rate of both pigments between meat and viscera, and to evaluate the feasibility of discoloration of oyster meat. The development of brownish pigment and the toss of free tyrosine in oyster were also determined to compare the readiness of color development. In addition the influence of processing and storage conditions to the dispersion rate and the tendency of discoloration, and finally the effect of inhibitor were discussed. The results showed that greening or yellowing was initiated by the dispersion of chlorophyll or carotenoids from viscera to the meat of oyster, and the dispersion rate of carotenoid was much higher than the chlorophyll's, so that, yellowing appeared a leading reaction of discoloration. The dispersion rate was obviously fastened by raising the temperature in the process of sterilization and storage. Consequently, the low temperature storage could largely retard the occurance of yellowing or greening of oyster meat. The pH control of canned oyster did not seem to affect the dispersion of pigment but significantly did on the stability of the piqments. Browning by the reaction of sugar-amino condensation and enzymatic oxidation of tyrosine was positively detected in canned oyster meat. The development of brownish color was influenced rather by the storage temperature than the heating process. Addition of sodium sulfite in can or treating the boiled oyster with sulfite solution prior to filling seemed possibly inhibit the color development particularly in cold-storaged oyster meat.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.548-553
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• 1999

A production of $\beta-Carotene$was attempted in a fed-batch culture of Blakeslea trispora by controlling both foam and dissolved oxygen in the presence of surfactant, Span 20. Results obtained from the shake flask cultures indicated that a high concentration of dissolved oxygen was needed for both cell growth and $\beta-Carotene$ synthesis, and the optimal concentration of glucose was found to be in the range of 50-100 g/l. In order to maintain the dissolved oxygen concentration level at higher than 50% of air saturation, pure oxygen was automatically sparged into the medium with air. Foam was controlled by bypassing air from the submerged aeration to the headspace in response to the foam that was caused by Span 20. High agitation speed was found to be detrimental to the cell growth due to shear damage, even though it provided sufficient dissolved oxygen. On the other hand, a low aeration speed caused stagnant regions in the fermentor because of improper mixing. Thus, for the fed-batch operation, agitation speed was increased gradually from 300 to 700 rpm to prevent cell damage at the initial stage of fermentation and to give efficient mixing for a viscous culture broth as the culture proceeded. By controlling dissolved oxygen and foam, a high concentration of $\beta-Carotene$otene (1,190 mg/l) was obtained in 6 days of the fed-batch culture of B. trispora with 2.5% of the dry cell weight, which was approximately 5 times higher than that of the batch cultures.

• Journal of Nutrition and Health
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• v.19 no.3
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• pp.211-223
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• 1986

In this experiment forty-eight Sprague Dawley male rats were chosen and used in order to measure the growth rates and to see the effects of lead acumulation in their organs resulting from variously controlled lead protein diet. Protein sources were casein and isolated soyprotein (ISP), and each source was divided into three groups : 7% low protein [LP], 20% standard protein (SP) and 40% high protein (HP) groups. The six experimental groups were given lead acetate(25 mg/kg B.W.) and six control groups were given sodium chloride by oral administration 6 times a week for weeks. The results from this experiment were summeraized as following ; 1) Food consumption, weight gain, organ weight and food efficiency ; Lead acetate administration with protein source had no effects on food consumption, weight gain and organ weight . By their different levels of protein, food consumption of LP group was less the that of SP and HP groups after 3 weeks, weight gain of LP group was less than that of SP and HO groups after 1 weeks. The organ weight in LP group was significantly lower than SP and HP groups except teeth and adrenal s. Effect of lead acetate administration on food efficiency have significantly lower in LP-ISP diet and HP -casein diet than other groups only first week. By their different levels LP group showed significantly lower than SP group until 3 weeks. 2) Hematopoietic effect ; The hematopoieteic effect was not influencec by lead acdtate administration and protein source. But the LP group showed a significantly lowe hematopoietic effect than the SP, HP, groups. 3) Accumulation of lead in the liver, kidney, teeth by protein source showed no significantly differences. Accumulation of lead in blood, heart of LP group, spleen of LP and HP groups. femur of SP and HP groups fed with casein diet groups were significantly higher than fed with ISP diet groups. By their different levels of group showed generally higher than SP and HP groups. But accumulation of lead in teeth of HP group was high also.

• Journal of Nutrition and Health
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• v.19 no.4
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• pp.211-223
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• 1986

In this experiment forty-eight Sprague Dawley male rats were chosen and used in order to measure the growth rates and to see the effects of lead acumulation in their organs resulting from variously controlled lead protein diet. Protein sources were casein and isolated soyprotein (ISP), and each source was divided into three groups : 7% low protein [LP], 20% standard protein (SP) and 40% high protein (HP) groups. The six experimental groups were given lead acetate(25 mg/kg B.W.) and six control groups were given sodium chloride by oral administration 6 times a week for weeks. The results from this experiment were summeraized as following ; 1) Food consumption, weight gain, organ weight and food efficiency ; Lead acetate administration with protein source had no effects on food consumption, weight gain and organ weight . By their different levels of protein, food consumption of LP group was less the that of SP and HP groups after 3 weeks, weight gain of LP group was less than that of SP and HO groups after 1 weeks. The organ weight in LP group was significantly lower than SP and HP groups except teeth and adrenal s. Effect of lead acetate administration on food efficiency have significantly lower in LP-ISP diet and HP -casein diet than other groups only first week. By their different levels LP group showed significantly lower than SP group until 3 weeks. 2) Hematopoietic effect ; The hematopoieteic effect was not influencec by lead acdtate administration and protein source. But the LP group showed a significantly lowe hematopoietic effect than the SP, HP, groups. 3) Accumulation of lead in the liver, kidney, teeth by protein source showed no significantly differences. Accumulation of lead in blood, heart of LP group, spleen of LP and HP groups. femur of SP and HP groups fed with casein diet groups were significantly higher than fed with ISP diet groups. By their different levels of group showed generally higher than SP and HP groups. But accumulation of lead in teeth of HP group was high also.