• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.939-947
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• 2008

PCR-DGGE method was applied to analyze changes of microbial community in simultaneous nitrification and denitrification (SND) bioreactor with various DO concentrations. In the analysis of eubacterial community, band profiles of DGGE were similar with 2 or 1 mg/L DO concentrations in the reactor. Experimental results led to 16 different bacteria being identified, including 5 dominant strains(3 strains of Uncultured Bacterium, 1 strains of Bacillus, 1 strains of Uncultured Bacteroidetes). DGGE results at 0.5 mg/L DO concentration led to 12 strains being identified, including 7 dominant strains(5 strains of Uncultured Bacterium, 2 strains of Zoogloea sp.). DGGE results at 0.1 mg/L DO concentration led to 11 strains being identified, including 3 dominant strains(1 strains of Uncultured Bacterium, 2 strains of Zoogloea sp.). In DGGE band profiles of $\beta$-AOB($\beta$-Ammonia Oxidizing Bacteria), only one band was observed. This band had 97% similarity with Nitrosomonas sp. done DNB Y20. This band was clearly observed at the 2, 1 and 0.5 mg/L DO concentrations, while the brightness of the band at 0.1 mg/L DO concentration was mostly dimmed. In DGGE band profiles of denitrification process, 5 bands(3 strains of Uncultured organism containing nirS, 2 strains of Uncultured organism containing nirK) were observed. Among those bands, the brightness of one band was gradually increased at the lower DO concentrations. This band has 86% identity with Uncultured organism clone eS1 cd1 nirS gene, partial cds. Based on this result, it could be concluded that Uncultured organism clone eS1 cd1 nirS gene, partial cds is a predominant microorganism in the denitrification process.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.253-258
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• 2004

Purpose: Chitosan has been studied as a non-viral gene delivery vector, drug delivery carrier, metal chelator, food additive, and radiopharmaceutical, among other things. Recently, galactose-graft chitosan was studied as a non-viral gene and drug delivery vector to target hepatocytes. The aim of this study was to investigate the usefulness of nuclear imaging for in vivo evaluation of targeting the hepatocyte by galactose grafting. Methods and Materials: Galactosyl methylated chitosan (GMC) was produced by methylation to lactobionic acid coupled chitosan. Cytotoxicity of $^{99m}Tc$-GMC was determined by MTT assay. Rabbits were injected via their auricular vein with $^{99m}Tc$-GMC and $^{99m}Tc$-methylated chitosan (MC), the latter of which does not contain a galactose group, and images were acquired with a gamma camera equipped with a parallel hole collimator. The composition of the galactose group in galactosylated chitosan (GC), as well as the tri-, di-, or mono-methylation of GMC, was confirmed by NMR spectroscopy. Results: The results of MTT assay indicated that $^{99m}Tc$-GMC was non-toxic. $^{99m}Tc$-GMC specifically accumulated in the liver within 10 minutes of injection and maintained high hepatic uptake. In contrast, $^{99m}Tc$-MC showed faint liver uptake. $^{99m}Tc$-GMC scintigraphy of rabbits showed that the galactose ligand principally targeted the liver while the chitosan functionalities led to excretion through the urinary system. Conclusion: Bioconjugation with a specific ligand endows some degree of targetability to an administered molecule or drug, as in the case of galactose for hepatocyte in vivo, and evaluating said targetabililty is a clear example of the great benefit proffered by nuclear imaging.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.327-332
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• 2008

This study was conducted to evaluate the effects of dietary Bacillus subtilis on meat quality, growth performance and fecal malodor gas emission in finishing pigs. Thirty-six pigs (Landrace ${\times}$ Yorkshire ${\times}$ Duroc, $83.53{\pm}1.01\;kg$ average initial body weight) were used in a 35 d growth assay. Dietary treatments were 1) CON (basal diet), 2) B1 (basal diet + B. subtilis 0.1%) and 3) B2 (basal diet + B. subtilis 0.2%). The pigs were distributed into four pigs per pen with three replicate pens per treatments by completely randomized design. For the entire period, the final weight, ADO, ADFI and gain/feed were not significantly different among the treatments. There were no significant differences in meat quality (sensory evalution, meat color, TBARS, water holding capacity, drip loss, cooking loss and M. longissimus dorsi area) among the treatments. $H_2S$ was significantly decreased in B2 treatment compared to CON and B1 treatments (p<0.05). However, ammonia, mercaptans and acetic acid were not significantly different among the treatments. In conclusion, B. subtilis 0.2% treatments decreased fecal $H_2S$ gas emission in finishing pigs.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.201-210
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• 2000

Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mats. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributons. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks dial not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the $K_{I}$ vague increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.s.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.834-838
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• 2000

As an endeavor to establish a micropropagation system for Epimedium koreanum Nakai., this study was carried out to define methods to disinfect its explants and media for callus induction, proliferation and plant regeneration. The lowest infection rates by fungi or bacteria on apical and axillary bud explants of rhizome were observed when they were immerged in 0.3% NaOCl solution for 20 min after soaked in 0.1% $AgNO_3$ solution for 30 min, but leaf explants were seldom infected with fungi or bacteria by this disinfectant method. The highest rate of plantlet formation was obtained from the explants disinfected in 0.3% NaOCl solution for 20 min after soaked in 0.1% $AgNO_3$ solution for 60 min for tip buds and in 0.1 % $AgNO_3$ solution for 30 min for axillary buds of rhizome. Induction rate of callus was the highest from the explants disinfectd in 0.3% NaOCl solution for 20 min after soaked in 0.2% $AgNO_3$ solution for 15 min. Callus growth was proper in a modified 1/2 MS medium including half strength of $NH_4NO_3$ with $0.02-0.2mg{\cdot}L^{-1}$ BA and $2.0mg{\cdot}L^{-1}$ NAA. Low rate of plantlet regeneration was obtained in 1/2 UM or 1/2 White medium with $2.0mg{\cdot}L^{-1}$ BA and $0.2mg{\cdot}L^{-1}$ AA.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.101-111
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• 2017

Mineral carbonation is a technology in which carbonates are synthesized from minerals including serpentine and olivine, and industrial wastes such as slag and cement, of which all contain calcium or magnesium when reacted with carbon dioxide. This study aims to develop the mineral carbonation technology for commercialization, which can reduce environmental burden and process cost through the reduction of carbon dioxide using steel slag and the slag reuse after calcium extraction. Calcium extraction was conducted using NH4Cl solution for air-cooled slag and convert slag, and ${\geq}98%$ purity calcium carbonate was synthesized by reaction with calcium-extracted solution and carbon dioxide. And we conducted experimentally to minimize the quantity of by-product, the slag residue after calcium extraction, which has occupied large amount of weight ratio (about 80-90%) at the point of mineral carbonation process using slag. The slag residue was used to replace silica sand in the manufacture of cement panel, and physical properties including compressive strength and flexible strength of panel using the slag residue and normal cement panel, respectively, were analyzed. The calcium concentration in extraction solution was analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES). Field-emission scanning electron microscope (FE-SEM) was also used to identify the surface morphology of calcium carbonate, and XRD was used to analyze the crystallinity and the quantitative analysis of calcium carbonate. In addition, the cement panel evaluation was carried out according to KS L ISO 679, and the compressive strength and flexural strength of the panels were measured.

• Applied Biological Chemistry
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• v.19 no.3
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• pp.172-183
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• 1976

RNA, DNA and other phosphorus fractions were determined in the leaf and root of soybean plants different in phosphorus sensitivity grown in $NH_4-N,\;NO_3-N$ and urea medium. The phosphorus sensitive cultivars contained higher ASIP (acid soluble inorganic phosphorus) than the tolerant cultivars with all nitrogen sources. ASIP was highest in the urea treated plants and lowest in the nitrate treated plants. Total phosphorus content was mostly affected with increase in ASIP. When ASIP increased, acid solsuble organic phosphorus(ASOP), phospholipids (L-P), RNA-P, residual phosphorus (R-P) tended to increase, while DNA-P showed little change. The percent RNA-P or DNA-P of total phosphorus in the nitrate treated plant was twice that in the ammonium treated plant, which were also higher in tolerant cultivars regardless of nitrogen sources. The percent ASOP in total acid soluble phosphorus $(ASOP/ASP{\times}100)$ decreased as phosphorus sensitivity decreased. Indications are that phosphorus sensitivity depends on the relative sizes of phosphorus metabolic pools. Total dry matter yield was negatively correlated with total phosphorus (r=0.84 significant at 0.01P), ASIP (0.84 significant at 0.01P) and residual phosphorus (0.69 significant at 0.05P). ASOP showed positive correlation with L-P, RNA-P and DNA-P but negative with R-P. RNA-P was significanly correlated only with L-P (0.63 at P=0.01). There was significant interaction (0.01) among nitrogen sources, cultivars and phosphorus metabolic pools. Phosphorus sensitivity and ammonium toxicity appear to be same in view of energy metabolism, that is, the former inhibits the conversion of ATP to ADP (energy releasing) through phosphate potential while the latter inhibits ATP formation (energy storing).

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.39-46
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• 2011

NO oxidation is an important prerequisite step to assist the selective catalytic reduction (SCR) at low temperatures ($<200^{\circ}C$). Therefore, we conducted the lab- and bench-scales experiments appling the sodium chlorite powder ($NaClO_2(s)$) for the oxidation of NO to $NO_2$ and the carbon-based catalyst for the reduction of $NO_x$ and $SO_2$; the lab- and bench-scales experiments were conducted in laboratory and iron-ore sintering plant, respectively. In the lab-scale experiment, known concentrations of $NO_x$ (200 ppm), $SO_2$ (75 ppm), $H_2O$ (10%) and $NH_3$ (400 ppm) in 2.6 L/min were introduced into a packed-bed reactor containing $NaClO_2(s)$, then gases produced by the reaction with $NaClO_2(s)$ were fed into the carbon-based catalyst (space velocity = $2,000hr^{-1}$) at $130^{\circ}C$. In the bench-scale experiment, flue gases of $50Nm^3/hr$ containing 120 ppm NO and 150 ppm $SO_2$ were taken out from the duct of iron-ore sintering plant, then introduced into the flow reactor; $NaClO_2(s)$ were injected into the flow reactor using a screw feeder. Gases produced by the reaction with $NaClO_2(s)$ were introduced into the carbon-based catalyst (space velocity = $1,000hr^{-1}$). Results have shown that, in both lab- and bench-scales experiments, NO was oxidized to $NO_2$ by $NaClO_2(s)$. In addition, above 90% of $NO_x$ and $SO_2$ removal were obtained at the carbon-based catalyst. These results lead us to suggest that the combination of $NaClO_2(s)$ with the carbon-based catalyst has the potential to achieve the simultaneous removal of $NO_x$ and $SO_2$ at low temperature ($<200^{\circ}C$).

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.292-297
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• 2006

A research was carried out to investigate the release pattern of slow release nitrogen fertilizer compound(SRNC) that is latex coated urea(LCU) and to recommend the application rate of the fertilizer at dry seeding rice culture in Honam plain area. The experiment was conducted at experimental field(Jeonbug series, fine silty, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) of National Honam Agricultural Research Institute. A medium late maturing rice variety (Dongjinbyeo) was seeded at the rate of $60kg\;ha^{-1}$ by drill seeder on April 1, 1997 and March 30, 1998. Fertilizer application rate was $160-90-110kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Soil ammonium nitrate($NH_4-N$) contents remained higher in all SRNC plots than conventional ones and higher with the increase of SRNC application rate until panicle formation stage, but the contents was higher in the conventional than NRNC plots at the heading stage. The plant hight was taller in SRNC than conventional plots until maximum tiller stage, but became similar in both conventional and SRNC plots at heading stage. The culm and panicle number was greater in SRNC than conventional plots throughout all growth stage, but the effective tiller rate was higher in conventional ones. Nitrogen efficiency was higher in the SRNC than conventional plots, but the efficiency was decreasing with the higher SRNC level. The spikelet number per unit area was greater in SRNC than conventional plots, and increased with higher SRNC level. The more spikelet number with higher NRNC level resulted in lower 1,000-grain weight. The rice yield in conventional plot was similar with only 60% SRNC level, but lower than 80% and 100% SRNC levels. However, slight lodging was observed in 100% SRNC level. In conclusions, we recommend NRNC application level as 80% of standard nitrogen application for early dry seeding culture of rice Honam plain area.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.52-62
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• 2023

This study focused on determining the specific causes and prevention methods of mass fish deaths occurred in five reservoirs (Gagugi, Neupgokgi, Danggokgi, Sagokji, and Hangokji) in Andong-si. For this purpose, a survey of agricultural land and livestock in the upper part of the reservoirs and analysis of water quality in the reservoir irrespective of whether it rains or not were conducted. We attempted to examine the changes in dissolved oxygen (DO) in the surface and bottom layers of reservoirs and changes in DO depending on the amount of livestock compost and time. Based on the above investigations, treatment plans were established to efficiently control the inflow of contaminated water into reservoirs. The rainfall and farmland areas in the upper part of the reservoir were investigated using Google and aviation data provided by the Ministry of Land, Infrastructure, and Transport. The current status of livestock farms distributed around the reservoirs was also examined because compost from these farms can flow into the reservoir when it rains. Various water quality parameters, such as phosphate phosphorus (PO₄-P) and ammonium nitrogen (NH₃-N), were analyzed and compared for each reservoir during the rainy season. Changes in the DO concentration and electrical conductivity (EC) were also observed at the inlet of the reservoir during raining using an automated instrument. In addition, DO was measured until the concentration reached 0 ppm in 10 min by adding livestock compost at various concentrations (0.05%, 0.1%, 0.3%, and 0.5% by wt.), where the concentration of the livestock compost represents the relative weight of rainwater. The DO concentration in the surface layer of reservoirs was 3.7 to 5.3 ppm, which is sufficient for fish survival. However, the fish could not survive at the bottom layer with DO concentration of 0.0-2.1 ppm. When the livestock compost was 0.3%, DO required 10-19 h to reach 0 ppm. Considering these results, it was confirmed that the DO in the bottom layer of the reservoir could easily change to an anaerobic state within 24 h when the livestock compost in the rainwater exceeds 0.3%. The results show that the direct cause of fish mortality is the inflow of excessive livestock compost into reservoirs during the first rainfall in spring. All the surveyed reservoirs had relatively good topographical features for the inflow of compost generated from livestock farms. This keeps the bottom layer of the reservoir free of oxygen. Therefore, to prevent fish death due to insufficient DO in the reservoir, measures should be undertaken to limit the amount of livestock compost flowing into the reservoir within 0.3%, which has been experimentally determined. As a basic countermeasure, minerals such as limestone, dolomite, and magnesia containing calcium and magnesium should be added to the compost of livestock farms around the reservoir. These minerals have excellent pollutant removal capabilities when sprayed onto the compost. In addition, measures should be taken to prevent fish death according to the characteristics of each reservoir.