• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.482-490
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• 2018

Candida albicans infections are often problematic to treat owing to antifungal resistance, as such infections are mostly associated with biofilms. The ability of C. albicans to switch from a budding yeast to filamentous hyphae and to adhere to host cells or various surfaces supports biofilm formation. Previously, the ethanol extract from Paeonia lactiflora was reported to inhibit cell wall synthesis and cause depolarization and permeabilization of the cell membrane in C. albicans. In this study, the P. lactiflora extract was found to significantly reduce the initial stage of C. albicans biofilms from 12 clinical isolates by 38.4%. Thus, to assess the action mechanism, the effect of the P. lactiflora extract on the adhesion of C. albicans cells to polystyrene and germ tube formation was investigated using a microscopic analysis. The density of the adherent cells was diminished following incubation with the P. lactiflora extract in an acidic medium. Additionally, the P. lactiflora-treated C. albicans cells were mostly composed of less virulent pseudohyphae, and ruptured debris was found in the serum-containing medium. A quantitative real-time PCR analysis indicated that P. lactiflora downregulated the expression of C. albicans hypha-specific genes: ALS3 by 65% (p = 0.004), ECE1 by 34.9% (p = 0.001), HWP1 by 29.2% (p = 0.002), and SAP1 by 37.5% (p = 0.001), matching the microscopic analysis of the P. lactiflora action on biofilm formation. Therefore, the current findings demonstrate that the P. lactiflora ethanol extract is effective in inhibiting C. albicans biofilms in vitro, suggesting its therapeutic potential for the treatment of biofilm-associated infections.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.26-32
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• 2002

For commercial production of Korean fermented anchovy sauce through rapid fermentation, a bacterial strain which showed the high protease activity was isolated from a commercially fermented anchovy sauce. The isolate was Bacillus amyloliquefaciens, and named as B. amyloliquefaciens HTP-8. The incubation temperature, initial pH, and cultivation time for optimal production of protease by B. amyloliquefaciens HTP-8 were $30^{\circ}C$, 7.0, and 3 days, respectively. In jar fermenter, B. amyloliquefaciens HTP-8 showed higher protease activity when grown at pH 7.0. The protease was partially purified by 80% ammonium sulfate precipitation and CM-Sephadex C-50 ion exchange chromatography. The partially purified enzyme had specific activity of 103.3 units/mg, yield of 0.4%, and purification fold of 43.0. The optimal pH and temperature for the protease activity were 10.0 and $50^{\circ}C$, respectively. The protease was relatively stable at the pH range of 7.0~12.0 and at the temperatures below 4$0^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{＋}$ /, $Ba^{2＋}$ and selectively inhibited by PMSF, suggesting that it is a serine protease.

• Journal of Information Technology Services
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• v.22 no.1
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• pp.75-93
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• 2023

The game industry has grown not only by combining them with various technologies also introducing new types of business models such as P2P, F2P, and P2W. Furthermore, games which implemented X2E model with blockchain technology are recently in the spotlight of the public attention. As domestic game companies have also prospect the blockchain games feasible, they are seeking ways to expand their global market share by strengthening the X2E model. Hence, by carrying this new business model out, it is expected to diversify their global revenue stream, which was previously confined to Asia region. This study analyzed the case of companies that have implemented the P2E and C2E models in order to suggest the direction of development for the game platform in Web 3.0 era. The cases of P2E game platform, which constitute of Axie Infinity and Mir 4, encompass the compensation structure, the stabilization mechanism of the in-game token economy, and future strategies regarding blockchain gaming. Likewise, the platform structure, business model, and future growth potential was discussed in terms of C2E scheme, focusing on the ZEPETO and Roblox cases. Based on the above case analysis, this study attempted to provide information on the current limitations and development directions of the P2E and C2E platforms. The current limitations in legal and industrial aspects should be addressed to facilitate the blooming of blockchain and P2E game industry. In addition, the necessity of not only social support also improvement on the technology and social stigma of full-time creators is ought to be emphasized in an effort to encourage the development of C2E platforms.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.82-89
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• 2009

Two in vitro experiments were conducted to examine the effects of propionate precursors in the dicarboxylic acid pathway on ruminal fermentatation characteristics, $CH_4$ production and degradation of feed by rumen microbes. Fumarate or malate as sodium salts (Exp. 1) or acid type (Exp. 2) were added to the culture solution (150 ml, 50% strained rumen fluid and 50% artificial saliva) to achieve final concentrations of 0, 8, 16 and 24 mM, and incubated anaerobically for 0, 1, 3, 6, 9 and 12 h at $39^{\circ}C$. For both experiments, two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were prepared in a nylon bag, and were placed in a bottle containing the culture solution. Addition of fumarate or malate in both sodium salt and acid form increased (p<0.0001) pH of culture solution at 3, 6, 9 and 12 h incubations. The pH (p<0.0001) and total volatile fatty acids (VFA, p<0.05) were enhanced by these precursors as sodium salt at 3, 6 and 9 h incubations, and pH (p<0.001) and total VFA (p<0.01) from fumarate or malate in acid form were enhanced at a late stage of fermentation (9 h and 12 h) as the addition level increased. pH was higher (p<0.001) for fumarate than for malate as sodium salt at 3 h and 6 h incubations. Propionate ($C_3$) proportion was increased (p<0.0001) but those of $C_2$ (p<0.05) and $C_4$ (p<0.01 - p<0.001) were reduced by the addition of sodium salt precursors from 3 h to 12 incubation times while both precursors in acid form enhanced (p<0.011 - p<0.0001) proportion of $C_3$ from 6h but reduced (p<0.018 - p<0.0005) $C_4$ proportion at incubation times of 1, 3, 9 and 12 h. Proportion of $C_3$ was increased (p<0.05 - p<0.0001) at all incubation times by both precursors as sodium salt while that of $C_3$ was increased (p<0.001) from 6h but $C_4$ proportion was decreased by both precursors in acid form as the addition level increased. Proportion of $C_3$ was higher (p<0.01 - p<0.001) for fumarate than malate as sodium salt from 6 h incubation but was higher for malate than fumarate in acid form at 9 h (p<0.05) and 12 h (p<0.01) incubation times. Increased levels (16 and 24 mM) of fumarate or malate as sodium salt (p<0.017) and both precursors in acid form (p<0.028) increased the total gas production, but no differences were found between precursors in both chemical types. Propionate precursors in both chemical types clearly reduced (p<0.0001 - p<0.0002) $CH_4$ production, and the reduction (p<0.001 - p<0.0001) was dose dependent as the addition level of precursors increased. The $CH_4$ generated was smaller (p<0.01 - p<0.0001) for fumarate than for malate in both chemical types. Addition of fumarate or malate as sodium type reduced (p<0.004) dry matter degradation while both precursors in both chemical types slightly increased neutral detergent fiber degradability of feed in the nylon bag.

• Journal of Aquaculture
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• v.9 no.2
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• pp.169-178
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• 1996

This experiment was conducted to develop an experimental model and a semipurified diet for vitamin C requirement study in juvenile Korean rockfish, Sebastes schlegeli. Prior to the start of the feeding trial, fish were fed the control diet for four weeks to deplete their body reserves of vitamin C, Then fish were divided into six groups and given one of the laboratory developed semipurified diets supplementing either 0 (control), 25, 50, 75, 150, o. 1500 mg L-ascorhic acid (AA)/kg diet for eight weeks. Fish fed control diet had lower hematocrit than did fish from groups fed the other diets (P<0.05). Also these fish had significantly lower percent weight gain (WG), feed conversion ratio (FCR) and muscle AA than did fish fed diets containing 150 and 1500 mg AA/kg diet (P<0.05). Diet analysis of vitamin C showed that the control diet had 39,7 mg AA/kg diet. Therefore, these fingings suggest that the experimental model and the semipurified diet can be useful for vitamin C requirement study, and the dietary vitamin C requirement is greater than 40 mg AA/kg diet, but 150 mg AA/kg diet is adequate for the maximum growth in juvenile Korean rockfish.

• Textile Coloration and Finishing
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• v.11 no.5
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• pp.13-21
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• 1999

In this study, selected cotton fabrics and polyester/cotton(P/C) blended fabrics are treated with a soluble polyurethane(SPU) and then, printed by heat transfer to determine the effect of SPU treatment on dye uptake of the samples. The results obtained are as follows： 1) In heat transfer, dye-uptake gets higher in Vopotion to temperature and time. The optimum printing temperature and printing time of C.I. Disperse Orange 3 and C.I. Disperse Violet 1 are $200^\circ{C}$ and 50sec. 2) Dye-uptake gets higher according to SPU concentration ; both cotton and P/C fabrics show the highest at $100g/\ell$. 3) In color, as temperature, time and SPU concentration increase, P/C fabrics show more yellowish orange color than cotton fabrics in case of C.I. Disperse Orange 3 and P/C fabrics show more reddish violet color than cotton fabrics in case of C.I. Disperse Violet 1. 4) All fastness of cotton and P/C fabrics treated with SPU are good, but color fastness to washing and water of cotton fabrics treated with SPU are not good.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.872-877
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• 2013

In a previous study, we isolated and reported a second species of the Saccharophagus genus, Saccharophagus sp. strain Myt-1. In the present study, an alginate lyase gene (algMytC) from the genomic DNA of Myt-1 was cloned and characterized. The DNA sequence fragment obtained contained an open reading frame of 1,032 bp that encoded a protein of 343 amino acids with an estimated molecular mass of 37.6 kDa and a pI of 6.60. The deduced protein, AlgMytC, had the conserved amino acid sequences (RTELREM, QIH, YFKAGVYNQ) of the polysaccharide lyase family 7. A BLAST homology search indicated that AlgMytC shared an amino acid sequence identity of 95.9% with alg7A of S. degradans 2-40. The cloned and purified AlgMytC protein showed optimal activity at $40^{\circ}C$, and retained more than 90% of its total activity even after treatment at $25^{\circ}C$ for 24 h. AlgMytC was very alkaliphilic with an optimal pH of 9.0, and more than 90% of its activity was retained in the pH range 8.5-10.0. Moreover, AlgMytC was stable over a wide pH range. The activity of AlgMytC was also stable in the presence of various detergents.

• Journal of Korea Foundry Society
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• v.17 no.4
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• pp.385-392
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• 1997

The main objective of this study is to investigate the microstructure and tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method. Die casting was performed using the preheated mold at the pouring temperature range of $620{\sim}750^{\circ}C$ under the pressure of $1,039 kgf/cm^2$. The low speed and a following high injection speed were 0.4 and 2.1 m/s, respectively. The microstructure of $SiC_p$/Al alloy composites fabricated by die casting method was found to be finer than that of composites fabricated by gravity casting. Also, SiC particulates were homogeneously distributed in refined Al matrix due to rapid solidification. The tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method was found to be varied with cast temperature. The maximun tensile strength of $SiC_p$(10 vol.% and 20 vol.%)/Al alloy composites showed 380 MPa at the cast temperature of $750^{\circ}C$ and 363 MPa at the cast temperature of $700^{\circ}C$, respectively.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.279-284
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• 2013

The phenolic beads in macrosize range were obtained by suspension polymerization at $98^{\circ}C$ from phenol and formaldehyde in the presence of basic catalyst with a phenol to formaldehyde (P/F) range of 1:1~1:4, and they were carbonized to spherical carbon beads under nitrogen at $700^{\circ}C$. Thermal analysis on spherical phenolic beads obtained by suspension polymerization showed that the postcuring process is essential. In order to optimize the suspension polymerization, the effects of the P/F molar ratio, the pH of catalyst, and the molecular weight of stabilizer on the size distribution and yield of spherical phenol beads were examined separatively. The particle size was increased whereas the yield was decreased with P/F molar ratio. The increasing basicity of catalyst made the particle size to increase, while the molecular weight of stabilizer had more effect on the yield rather than on the particle size distribution. The thermal stability of the spherical phenolic beads obtained through postcure was also examined by TGA. The phenol beads of high P/F ratio still showed the weight loss at $220^{\circ}C$ even after postcure due to the high possibility of dibenzyl ether, while those of low P/F ratio showed the steady decrease in weight during $220^{\circ}C$ to $400^{\circ}C$, which showed that the optimal P/F ratio was 1:2.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.10
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• pp.495-499
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• 2004

Characteristics of ohmic Ni/Si/Ni contacts to n-type 4H-SiC are investigated systematically. The ohmic contacts were formed by annealing Ni/Si/Ni sputtered sequentially The annealings were performed at 950℃ using RTP in vacuum ambient and N₂ ambient, respectively. The specific contact resistivity(p/sub c/), sheet resistance(R/sub s/), contact resistance (R/sub c/) transfer length(L/sub T/) were calculated from resistance(R/sub T/) versus contact spacing(d) measurements obtained from TLM(transmission line method) structure. While the resulting measurement values of sample annealed at vacuum ambient were p/sub c/ = 3.8×10/sup -5/Ω㎠, R/sub c/ = 4.9 Ω and R/sub T/ = 9.8 Ω, those of sample annealed at N₂ ambient were p/sub c/ = 2.29×10/sup -4/Ω㎠, R/sub c/ = 12.9 Ω and R/sub T/ = 25.8 Ω. The physical properties of contacts were examined using XRD 3nd AES. The results showed that nickel silicide was formed on SiC and Ni was migrated into SiC. This result indicates that Ni/Si/Ni ohmic contact would be useful in high performance electronic devices.