• Journal of the Korean Ceramic Society
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• v.56 no.2
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• pp.130-145
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• 2019

Widespread commercialization of solid oxide fuel cells (SOFCs) is expected to be realized in various application fields with the advent of cost-effective fabrication of cells and stacks in high volumes. Cost-reduction efforts have focused on production yield, power density, operation temperature, and continuous manufacturing. In this article, we examine several issues associated with processing for SOFCs from the standpoint of the bimodal packing model, considering the external constraints imposed by rigid substrates. Optimum compositions of composite cathode materials with high volume fractions of the second phase (particles dispersed in matrix) have been analyzed using the bimodal packing model. Constrained sintering of thin electrolyte layers is also discussed in terms of bimodal packing, with emphasis on the clustering of dispersed particles during anisotropic shrinkage. Finally, the structural transition of dispersed particle clusters during constrained sintering has been correlated with the structural stability of thin-film electrolyte layers deposited on porous solid substrates.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.181-183
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• 2008

We developed simple and highly efficient synthesis method for [$^{11}C$]methionine using solid-phase extraction method. For synthesis, we used C18 cartridge. [$^{11}C$]methionine was synthesized on C18 cartridge according to the solid-phase [$^{11}C$]methylation of precursor L-homocysteine thiolactone hydrochloride. The radiochemical yields of [$^{11}C$]methionine was $48.9{\pm}7.93%$ decay corrected (results of 30 syntheses, mean$\pm$SD), with average production higher than 180 mCi. This procedure showed high yield and simple synthesis of [$^{11}C$]methionine.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.1028-1034
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• 2021

The effect of medium composition on enzyme and β-glucan production by Aspergillus oryzae KCCM 12698 was investigated. Brown rice, rice bran, nitrogen, and ascorbic acid are key components of the synthetic medium used in liquid-state fermentation. To determine the optimal concentrations of these components for enzyme and β-glucan production, we conducted one factor at a time experiments, which showed that the optimal concentrations were 30 g/l brown rice, 30 g/l rice bran, 10 g/l soytone, and 3 g/l ascorbic acid. Pretreatment of brown rice for 60 min prior to inoculation enhanced fungal biomass, while increasing the production of enzymes and β-glucan using solid-state fermentation. Maximum fungal biomass of 0.76 mg/g, amylase (26,551.03 U/g), protease (1,340.50 U/g), and β-glucan at 9.34% (w/w) were obtained during fermentation. Therefore, solid-state fermentation of brown rice is a process that could enhance yield and overall production of enzymes and β-glucan for use in various applications.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1648-1654
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• 2008

Superoxide dismutase (SOD) removes damaging reactive oxygen species from the cellular environment by catalyzing the dismutation of two superoxide radicals to hydrogen peroxide and oxygen. Extracellular superoxide dismutase (EC-SOD) is a tetramer and is present in the extracellular space and to a lesser extent in the extracellular fluids. Increasing therapeutic applications for recombinant human extracellular superoxide dismutase (rEC-SOD) has broadened interest in optimizing methods for its purification, with a native conformation of tetramer. We describe a solid phase refolding procedure that combines immobilized metal affinity chromatography (IMAC) and gel filtration chromatography in the purification of rEC-SOD from Escherichia coli. The purified rEC-SOD tetramer from the $Ni^{2+}$-column chromatography is refolded in Tris buffer. This method yields greater than 90% of the tetramer form. Greater than 99% purity is achieved with further purification over a Superose 12PC 3.2/30 column to obtain the tetramer and specific activities as determined via DCFHDA assay. The improved yield of rEC-SOD in a simple chromatographic purification procedure promises to enhance the development and therapeutic application of this biologically potent molecule.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.369-373
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• 2004

In order to elucidate the possibility of artificial production of p. ferulae by solid-state culture, the optimization of culture conditions was carried out. When $NH_4H_2PO_4$ and $CaCO_3$ were used in the cultures using test tube with 30 g of Populus sawdust at $25^{\circ}C{\pm}1$ in the dark, the favored mycelial growth was observed with $1\%$ of $NH_4H_2PO_4$ and the production of polysaccharide was 7.85 mg/100 mg of mycelium with $1\%$ of $CaCO_3$. The mixtures of $80\%$ of Populus Sawdust and $20\%$ of rice bran at $60\%$ of water content were determined to be optimal for the production of fruiting bodies in the sawdust culture. When three treatments containing various ratios of garlic powder were conducted, yields of fruiting bodies were drasti[ally higher than those of Synthetic mixture without garlic powder The highest yield (143 g/bag) was obtained with $7\%$ garlic powder. The yield of synthetic mixture containing $7\%$ of garlic powder was $83\%$ higher than that of Sawdust culture. The reason why garlic powder did support growth was not clear but it is possible that garlic powder might contain effective components for the formation of fruiting body. The optimal synthetic mixture composition consisted of cotton seed $77\%$, lime $6.4\%,\;K_2HPO_4\;0.2\%,\;KH_2PO_4\;0.2\%,\;CaHPO_4\;0.2\%$, corn flour $4\%$, wheat flour $5\%$, and garlic pow-der $7\%$.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.1004-1014
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• 2013

Six nonpathogenic fungal strains isolated from alkaline soils of Buenos Aires Province, Argentina (Acremonium murorum, Aspergillus sidowii, Cladosporium cladosporoides, Neurospora tetrasperma, Purpureocillium lilacinum (formerly Paecilomyces lilacinus), and Westerdikella dispersa) were tested for their ability to produce keratinolytic enzymes. Strains were grown on feather meal agar as well as in solid-state and submerged cultures, using a basal mineral medium and "hair waste" as sole sources of carbon and nitrogen. All the tested fungi grew on feather meal agar, but only three of them were capable of hydrolyzing keratin, producing clear zones. Among these strains, P. lilacinum produced the highest proteolytic and keratinolytic activities, both in solid-state and submerged fermentations. The medium composition and culture conditions for the keratinases production by P. lilacinum were optimized. Addition of glucose (5 g/l) and yeast extract (2.23 g/l) to the basal hair medium increased keratinases production. The optimum temperature and initial pH for the enzyme production were $28^{\circ}C$ and 6.0, respectively. A beneficial effect was observed when the original concentration of four metal ions, present in the basal mineral medium, was reduced up to 1:10. The maximum yield of the enzyme was 15.96 $U_c/ml$ in the optimal hair medium; this value was about 6.5-fold higher than the yield in the basal hair medium. These results suggest that keratinases from P. lilacinum can be useful for biotechnological purposes such as biodegradation (or bioconversion) of hair waste, leading to a reduction of the environmental pollution caused by leather technology with the concomitant production of proteolytic enzymes and protein hydrolyzates.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.61-64
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• 2013

Biomass is well known for organic resources photosynthesized by carbon dioxide water in the air and thus it can be widely used in the form of energy and production for various kinds of materials. Through pyrolysis, biomass can be transformed into solid(biochar), liquid(bio-oil), and combustible gas on the different condition of temperature and heating rate. That's why biomass can be practically used to preprocess and produce a variety of elements. This work is to analyze the characteristics of slow pyrolysis of three different kinds of biomass extracted from Indonesia. They showed similar moisture content and combinations of combustible matters and had quite a large discrepancy in the ash among them like 2.1 & of Bagasse, 91% of PKS, and 20.9% of Paddy Straw, respectively. yield of biochar, solid form of the biomass, steadily decreased when the temperature went up and that of bio-oil the highest at the temperature of 500 degrees Celsius. At the same temperature range, PKS bio-oil showed 51.4 % of yield and Bagasse had 55.1% while it turned out that Paddy straw showed the lowest yield of 37.2%. The apparent density was also measured to figure out the density of each product from the pyrolysis experiments at the temperature of 500 degrees Celsius. The result was like these; the density of biochar was 0.17, the lowest, and that of Tree stem was 1.3 when mixed by an equal amount of biochar and bio-oil.

• The Korean Journal of Nuclear Medicine
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• v.24 no.1
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• pp.101-107
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• 1990

To develop $^{131}I-labelled$ m-iodobeneylguanidine $(^{131}I-MIBG)$, various experiments such as synthesis of MIBG, establishment of labelling conditions, determination of radiochemical purity, and examination of stability were carried out. 1) m-Iodobenzylguanidine (MIBG) sulfate was synthesized with a total yield of 62.4% by the condensation of m-iodobenzylamine hydrochloride with cyanamide via MIBG bicarbonate. Its physical properties, IR, $^1H-NMR$, and elemental analysis data were nearly identical to those of literature. 2) Freeze-dried or vacuum-dried kit vials were prepared from the mixture so as to contain MIBG (2 mg), ascorbic acid (10 mg), copper (II) sulfate (0.14 mg), and tin (II) sulfate (0.5 mg) per vial. Copper ( I ) catalyzed radioiodination of MIBG was carried out using kit vials and 0.01 M $H_2SO_4$ as solvent at $100^{\circ}C$ for 30 min under nitrogen atmosphere (optimal conditions). Labelling yield was 98% and radiochemical purity was 99.5%, respectively. 3) Solid-phase radioiodination of MIBG was carried out at $155^{\circ}C$ for 30 min using the prepared vials to contain MIBG (2 mg) and ammonium sulfate (10 mg). Duplicate reactions under the same conditions showed labelling yield of 95% and radiochemical purity of 99.5%. 4) $^{131}I-MIBG$ prepared either by catalytic or by solid-phase exchange method showed radio-chemical purity of 99% even after 3 days storing at room temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.395-400
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• 1993

Four sheep per treatment were fed either control or 3% calcium salts of long-chain fatty acids (Ca-LCFA) in a total mixed ration (TMR). Feed and free water intakes were not different, but digestibilities of crude protein and crude fiber were lower (p<0.05) and that of crude fat was higher (p<0.05) for sheep fed Ca-LCFA than for control sheep. Dry matter digestibility, ruminal pH and microbial protein yield were not different between treatments and ammonia-N concentration in the rumen was higher for sheep fed Ca-LCFA than for control sheep. A 60-day milk production trial was conducted with thirty lactation Holstein cows. Fifteen cows per treatment were fed TMR containing either control or 3% Ca-LCFA ad libitum. Feed intake was not different between treatments, but milk yield was significantly higher (p<0.05) for cows fed Ca-LCFA than for control cows. Milk fat percentage was slightly higher and milk protein was lower for cows fed Ca-LCFA than for control cows. Lactose and total solid contents in milk were not different between treatments.

• Korea-Australia Rheology Journal
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• v.15 no.1
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• pp.9-17
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• 2003

The rheological behaviour of anatase $TiO_2$ with organic coating has been investigated extensively in this study. The yield stress was measured over a wide range of solids concentration and pH using stress-controlled and speed-controlled rheometers. The organic treatment leads to a shift of the isoelectric point (IEP) from around pH 5.5 to pH 2.4. A maximum yield stress occurs in the vicinity of the isoelectric point determined by electrokinetic measurements. The transition of rheological behaviour between elastic solid and viscous liquid is represented by a stress plateau in a plot of stress against strain. It is hypothesised that the slope of the stress plateau reflects the uniformity of the structure, and hence the distribution of bond strength. Altering the concentration and the surface chemistry can vary the bond strength and its distribution. therefore, resulting in different type of failure: "ductile-type" or "brittle-type". pH and volume fraction dependence of yield stress could be described quantitatively using existing models with reasonable agreement.easonable agreement.