• Journal of Environmental Science International
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• v.29 no.5
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• pp.495-506
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• 2020

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

• Animal Bioscience
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• v.36 no.4
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• pp.671-678
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• 2023

Objective: Previous studies isolated the thermophilic ammonium-tolerant (TAT) bacterium Bacillus sp. TAT105 that grew in composting swine manure with the assimilation of ammonium nitrogen and reduced ammonia emissions during composting. Those studies also investigated the potential for applications of TAT105 to composting. It was observed that the concentration of TAT bacteria, phylogenetically close to TAT105, increased during composting. The objectives of this study were to identify the phylogenetic placement of these TAT bacteria and investigate their distribution in various composts. Methods: The phylogenetic placement of TAT105 was examined based on the sequence of 16S ribosomal RNA gene. The genomic DNA homology between TAT105 and the type strains of bacterial species that were phylogenetically close to TAT105 were examined by DNA-DNA hybridization. Moreover, the tolerances of these strains to NH₄Cl and NaCl were analyzed using a cultivation method. Concentrations of TAT bacteria in various composts were evaluated using an agar medium specific to TAT bacteria and polymerase chain reaction followed by restriction fragment length polymorphism analysis. Results: TAT105 was most closely related to Bacillus thermolactis and Bacillus kokeshiiformis. Many variants of these species have been detected in various environments, including composts. The type strains of these species displayed TAT characteristics that were similar to those of TAT105. Among the composts examined in this study, TAT bacteria were detected at high concentrations (10⁵ to 10⁹ colony forming units per gram of dry matter) in most of the composts made from cattle manure, swine manure, bark, and excess sludge. Conclusion: TAT bacteria comprised B. thermolactis, B. kokeshiiformis, and their phylogenetically close relatives. They were considered to be adaptable to composting of some certain materials, and a favorable target for searching for strains with some useful function that could be applied to composting of these materials.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.4
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• pp.239-244
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• 1973

Effects of nitrogen sources on free amino acids, and on photosynthsis-respiration equilibrium point of various positional leaf in soybean were investigated in relation to phosphorus sensitivity. The content of free amino acids was highest in ammonium and lowest in urea treated leaves. Glycine, serine, alanine and especially histidine were high in the ammonium treated leaves. Aspartic acid was high in the nitrate treated leaves. Photosynthesis respiration equilibrium point was higher in the sensitive cultivars, and higher with ammonium than with nitrate. The excess ammonium in plant appears to draw out an intermediate metabolite from carbon fixation pathway resulting in photosynthetic inhibition and activate pentoses phosphate pathway and photorespiration. Such phenomena were likely accentuated in phosphorus sensitive variety.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.116-122
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• 2007

An efficient enzyme system for the synthesis of L-tyrosine was developed using a fed-batch reactor with continuous feeding of phenol, pyruvate, and ammonia. A thermo- and chemostable tyrosine phenol-lyase from Symbiobacterium toebii was employed as the biocatalyst in this work. The enzyme was produced using a constitutive expression system in Escherichia coli BL21, and prepared as a soluble extract by rapid clarification, involving treatment with 40% methanol in the presence of excess ammonium chloride. The stability of the enzyme was maintained for at least 18 h under the synthesis conditions, including 75 mM phenol at pH 8.5 and $40^{\circ}C$. The fed-batch system (working volume, 0.51) containing 1.0 kU of the enzyme preparation was continuously fed with two substrate preparations: one containing 2.2 M phenol and 2.4 M sodium pyruvate, and the other containing 0.4 mM pyridoxal-5-phosphate and 4M ammonium chloride (pH 8.5). The system produced 130g/I of L-tyrosine within 30h, mostly as precipitated particles, upon continuous feeding of the substrates for 22 h. The maximum conversion yield of L-tyrosine was 94% on the basis of the supplied phenol.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.727-732
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• 2016

A simple and rapid spectrophotometric method has been developed to enable the determination of plutonium concentration in an irradiated fuel solution in the presence of all fission products. An excess of ceric ammonium nitrate solution was employed to oxidize all the valence states of plutonium to +6 oxidation state. Interference due to the presence of fission products such as ruthenium and zirconium, and corrosion products such as iron in the envisaged concentration range, as in the irradiated fuel solution, was studied in the determination of plutonium concentration by the direct spectrophotometric method. The stability of plutonium in +6 oxidation state was monitored under experimental conditions as a function of time. Results obtained are reproducible, and this method is applicable to radioactive samples resulting before the solvent extraction process during the reprocessing of fast reactor spent fuel. An analysis of the concentration of plutonium shows a relative standard deviation of <1.2% in standard as well as in simulated conditions. This reflects the fast reactor fuel composition with respect to uranium, plutonium, fission products such as ruthenium and zirconium, and corrosion products such as iron.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.3
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• pp.185-191
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• 1973

Effects of nitrogen sources on chlorophyll, activity of some oxidases in soybean leaves were investigated in relation to phosphorus sensitivity. Ammonium and urea culture accelerated leaf senescence more in phosphorus sensitive cultivars. The leaf senescence patterns affected by nitrogen sources were clearly indicated by intact leaf absorbance. Absorption maximum (670nm in methanol extraction or 685nm in intact leaf), was not changed by nitrogen source in the same method. According to leaf senesence pattern general physiological sensitivity pattern was discussed. IAA-oxidase activity was higher in the phosphorus tolerant cultivars and nitrate treatment than in the sensitive cultivars and ammonium treatment. Glycolate oxidase activity was higher in the sensitive cultivars and nitrate treatment. Polyphenol oxidase activity was higher in the tolerant cultivars and urea treatment. It is concluded that the excess ammonium, to which excess phosphorus is highly similar in physiological effect, disturbs the photosynthetic system by inhibition of ATP generation (photo-and oxidative phosphorylation).

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.829-835
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• 2016

An excess in the nutrients such as nitrogen and phosphate leads to a phenomenon called eutrophication. In order to avoid this, numerous methods have been used to remove excess nutrients in the water. In this study, the use of a chemical method was assessed through the formation of magnesium ammonium phosphate. The difference in the removal efficiency of seawater and sea salt solution as primary sources of $Mg^{2+}$ ions and $Ca^{2+}$ ions for the formation of magnesium ammonium phosphate (MAP) and hydroxyapatite (HAP) respectively, were observed, taking into account the changes in pH and concentration. The results showed that seawater removed about 90 % phosphate and less than 50 % ammonia in sewage water condition, whereas the sea salt solution removed almost 90 % phosphate and 70 % ammonia in solution at pH 9 and 10 mM concentration of sea salt which further increases as the optimum ${Mg/PO_4}^{3-}$, ${NH_4}^+$ ratio reaches 2. The difference in the removal efficiency of seawater and sea salt was due to the fact that the set-ups were prepared in different conditions. This study suggests that both seawater and sea salt can be used to remove nutrients from the water. The relatively higher removal of phosphate can be explained by the formation of HAP from free $Ca^{2+}$ ions initially present in seawater and sea salt solution.

• Elastomers and Composites
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• v.44 no.4
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• pp.447-454
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• 2009

We synthesized polyester-diol containing Cloisite 30B which is exfoliated during the synthesis. First, esterification was conducted with excess adipic acids and two 2-hydroxyethyl groups of the tertiary ammonium tethered to Cloisite 30B silicate layer. Due to the small molecular size of adipic acid ($d{\approx}3.0\;{\AA}$, $L{\approx}9.3\;{\AA}$), it penetrated into the interlayer of Cloisite 30B, reacted with the 2-hydroxyethyl groups, and produced the tertiary ammonium that has the two ethyl-ester adipic acid groups, one methyl group, and one hydrogenated alkyl group. Through the esterification, the molecular size of the tertiary ammonium increased and as the result, the basal space of Cloisite 30B increased from $18.4\;{\AA}$ to more than $58.3\;{\AA}$. The produced ethyl-ester adipic acid and unreacted adipic acid reacted with excess diethylene glycol ([COOH]/[OH]${\approx}0.6$) to be polyester-diol. The COOH conversion calculated from the acid value of the reactant mixture was 94%. The number average molecular weight and PDI of the produced polyester-diol were 830 g/mol and 1.2, respectively.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.76-87
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• 2005

Various disorders cause hyperammonemia during childhood. Amongthem are those caused by inherited defects in urea synthesis and related metabolic pathways. These disorders can be grouped into two types: disorders of the enzymes that comprise the urea cycle, and disorders of the transporters or metabolites of theamino acids related to the urea cycle. Principal clinical features of these disorders are caused by elevated levels of blood ammonium. Additional disease-specific symptoms are related to the particular metabolic defect. These specific clinical manifestations are often due to an excess or lack of specific amino acids. Treatment of urea cycle disorders and related metabolic diseases consists of nutritional restriction of proteins, administration of specific amino acids, and use of alternative pathways for discarding excess nitrogen. Although combinations of these treatments are extensively employed, the prognosis of severe cases remains unsatisfactory. Liver transplantation is one alternative for which a better prognosis is reported.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.412-415
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• 2017

In this study, the decomposition performance of ammonia dinitramide (ADN) based liquid monopropellant was evaluated by using metal supported alumina bead catalyst. Alumina bead was calcined at $1200^{\circ}C$, and Pt and Cu were impregnated on alumina bead by excess water impregnation using a rotary evaporator. The decomposition temperature ($T_{dec}$) of ADN-based liquid monopropellant was measured in a home-made batch reactor. The decomposition temperature of Cu/$Al_2O_3$ catalyst was lower than that of Pt/$Al_2O_3$ catalyst, and $T_{dec}$ was about $130^{\circ}C$.