• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.477-481
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• 1992

As a series of fundamental research projects to produce doenjang (Korean fermented soy paste) of better quality, two kinds of doenjang were manufactured from a traditional meju (Korean soy bean koji) and the mixed with Aspergillus oryzae and Bacillus natto, and histological changes in the cell structures of soy bean of the two were reported doenjang samples were observed and compared during the entire period of fermentation processes. Cell walls of the soy bean were ruptured by pressure and heat during the pressure cooking process and some of them were observed to have the ghost-like shapes. Remarkable differences in the plasmolysis of the cytoplasms were observed between the seed coat and the inner part of soy bean. Small vacuoles resulting from the fusion of the glycoprotein globules by protease and from the hydrolysis of the starch granules by amylase were also observed. Penetration of microorganisms was transferred from the seed coat to the inside of soy bean as the fermentation proceeded. Slimy substances were observed on the seed coat and the parenchyma cells of soy bean fermented with the mixed with Aspergillus oryzae and Bacillus natto. Cell walls of soy bean became difficult to stain and they showed unusual, polygonal shapes as the fermentation proceeded. Samples fermented with the mixed with Aspergillus oryzae and Bacillus natto showed more remarkable tendencies than traditional meju.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1503-1509
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• 2014

With the purpose of facilitating the process of stable strain generation, a shuttle vector for integration of genes via a double recombination event into two ectopic sites on the Sulfolobus acidocaldarius chromosome was constructed. The novel chromosomal integration and expression vector pINEX contains a pyrE gene from S. solfataricus P2 ($pyrE_{sso}$) as an auxotrophic selection marker, a multiple cloning site with histidine tag, the internal sequences of malE and malG for homologous recombination, and the entire region of pGEM-T vector, except for the multiple cloning region, for propagation in E. coli. For stable expression of the target gene, an ${\alpha}$-glucosidase-producing strain of S. acidocaldarius was generated employing this vector. The malA gene (saci_1160) encoding an ${\alpha}$-glucosidase from S. acidocaldarius fused with the glutamate dehydrogenase ($gdhA_{saci}$) promoter and leader sequence was ligated to pINEX to generate pINEX_malA. Using the "pop-in" and "pop-out" method, the malA gene was inserted into the genome of MR31 and correct insertion was verified by colony PCR and sequencing. This strain was grown in YT medium without uracil and purified by His-tag affinity chromatography. The ${\alpha}$-glucosidase activity was confirmed by the hydrolysis of $pNP{\alpha}G$. The pINEX vector should be applicable in delineating gene functions in this organism.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.146-154
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• 2019

In this study, alkoxysilane-functionalized amphiphilic polymer (AFAP), which have hydrophilic segment and hydrophobic segment functionalized by alkoxysilane group at the same backbone, was synthesized and used as a dispersant and control agent for reaction rate in the preparation of colloidally stable organic-inorganic (O-I) hybrid sols. After reaction with fluorosilane compounds, fluorinated O-I hybrid sols were prepared and coated onto glass substrate to form hydrophobic O-I hybrid coating films through low-temperature curing process. Surface hardness and hydrophobicity of cured coating films were varied with type of solvent and composition of AFAP and fluorinated alkoxysilane compounds. At appropriate solvent and composition of fluorinated alkoxysilane compounds, O-I hybrid coating film having high transparency and surface hardness could be prepared, which could be applicable to cover window of solar cell and displays.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.816-822
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• 2005

Catharsius protease-2 (CPM-2) was isolated from the body of dung beetles, Catharsius molossus, using a three step purification process (ammonium sulfate fractionation, gel filtration on Bio-Gel P-60, and affinity chromatography on DEAE Affi-Gel blue). The purified CPM-2, having a molecular weight of 24 kDa, was assessed homogeneously by SDS-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of CPM-2 was composed of X Val Gin Asp Phe Val Glu Glu lie Leu. CPM-2 was inactivated by $Cu^{2+}\;and\;Zn^{2+}$ and strongly inhibited by typical serine proteinase inhibitors such as TLCK, soybean trypsin inhibitor, aprotinin, benzamidine, and ${\alpha}_1$-antitrypsin. However, EDTA, EGTA, cysteine, $\beta$-mercaptoethanol, E64, and elastatinal had little effect on enzyme activity. In addition, antiplasmin and antithrombin III were not sensitive to CPM-2. Based on the results of a fibrinolytic activity test, CPM-2 readily cleaved $A{\alpha}-$ and $B{\beta}$-chains of fibrinogen and fibrin, and y-chain of fibrinogen more slowly. The nonspecific action of the enzyme resulted in extensive hydrolysis, releasing a variety of fibrinopeptides of fibrinogen and fibrin. Polyclonal antibodies of CPM-2 were reactive to the native form of antigen. The ELISA was applied to detect quantities, in nanograms, of the antigen in CPM-2 protein.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.245-251
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• 1988

Thermolysin was immobilized on Dowex MWA-1 with 10% glutaraldehyde and incorpo rated into a fluidized-bed continuous coagulation scheme to make Cheddar type cheese. The activity yield of thermolysin was 25%. The immobillized thermolysin was stable at $60^{\circ}C$ in the presence of 1/200M calcium ions and the half-life value is 16 days at the temperature. Raw milk alkalified to pH 7.0 was passed through a column of thermolysin beads at $55^{\circ}C$, cultivated with Streptococcus cremoris and allowed to coagulate. A typical milk curd was formed to make Cheddar type cheese, avoiding troublesome microbial contamination successfully during continuous hydrolysis process. During ripening of this cheese for 6 months at $10^{\circ}C$, its ripening ratio and taste were similar to those of cheese prepared by the traditional method.

• Membrane Journal
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• v.2 no.1
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• pp.21-32
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• 1992

Hydrogen-permselective silica membranes were synthesized within tim walls of porous Vycor tubes by chemical vapor depostion of $SiO_2$. Film deposition was carried out using $SiCl_4$ hydrolysis either in the oppm shag reactants or in the one-sided geometry. At temperatures above $600^{\circ}C$ the permeation rate of hydrogen thorough the silica films varied between 0.01 and $025cm^3(STP)/cm^2-min-atm$ depending on the reaction geometry and the $H_2 : N_2$ permeation ratio was about 1000. Permeation rates of both $H_2$ and $N_2$ increased with increasing temperature. The silica membranes produced by one-sided deposition have higher hydrogen permmeation rates than those produced by the opposing reactants geometry although the membranes formed in an opposing reactants geometry were relatively stable during the heat treatment or after exposure to ambient air. These membranes can be applied to high temperature gas separations or membrane reactors once the film deposition process is optimized to get high permeability as well as good stability.

• Journal of the Korean Ceramic Society
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• v.32 no.5
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• pp.594-600
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• 1995

Spherical alumina gel powders were produced by hydrolysis of aluminum sec-butoxide (Al(sec-OC4H9)3) in a n-octanol/acetonitrile mixed solvent. The enlargement of particle size was induced by increasing HPC (hydroypropylcellulose) concentration (0.005, 0.1, and 0.05 g/ι) and emulsion-state aging time (10 min and 360 min). Mean particle sizes of dried alumina gel powders increased from 1.4 ${\mu}{\textrm}{m}$ to 3.5${\mu}{\textrm}{m}$ at 10-min emulsion-state aging time and from 1.9${\mu}{\textrm}{m}$ to 4.1${\mu}{\textrm}{m}$ at 360-min emulsion-state aging time as HPC concentration increased from 0.005 g/ι to 0.05 g/ι. At the same HPC concentration, particle size of dried alumina gel powder increased with increasing of emulsion-state aging time from 10 min to 360 min. The increase in the average particle size of dried alumina gel powder with increase in HPC concentration was interpreted as the enlargement of particles from alkoxide emulsions unprotected by HPC. The produced dried gel powder calcined at 115$0^{\circ}C$ for one hour transformed to $\alpha$-alumina.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.902-908
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• 2003

Au/TiO$_2$ core-shell structure nanoparticles were synthesised by sol-gel process, and the morphology and crystallinity of TiO$_2$ shell were investigated by TEM and UV-Vis. absorption spectrometer. Au/TiO$_2$ core-shell structure nanoparticles could be prepared by the hydrolysis of TOAA (Titanium Oxide Acethylacetonate) in Au colloid ethanol solution with $H_2O$. The thickness of TiO$_2$ shell on the surface of Au particles was about 1 nm. To investigate the crystallinity of TiO$_2$ shell, UV light with 254 nm and radioactive lay of $^{60}$ CO were irradiated on the TiO$_2$ coated Au colloid ethanol solution. The surface plasmon phenomenon of Au nanoparticles appeared only when the radioactive lay was irradiated on the TiO$_2$ coated Au colloid ethanol solution. From these results, it was found that the TiO$_2$ shell was amorphous and the MUA (Mercaptoundecanoic Acid) layer on the Au particle for its dispersion didn't act as an obstacle to disturb the movement of electron onto the surface of Au particle.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.37-37
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• 2010

Silicate-silsesquioxane or siloxane-silsesquioxane hybrid thin films are strong candidates as matrix materials for ultra low dielectric constant (low-k) thin films. We synthesized the silicate-silsesquioxane hybrid resins from tetraethoxyorthosilicate (TEOS) and methyltrimethoxysilane (MTMS) through hydrolysis and condensation polymerization by changing their molar ratios ([TEOS]:[MTMS] = 7:3, 5:5, and 3:7), spin-coating on Si(100) wafers. In the case of [TEOS]:[MTMS] 7:3, the dielectric permittivity value of the resultant thin film was measured at 4.30, exceeding that of the thermal oxide (3.9). This high value was thought to be due to Si-OH groups inside the film and more extensive studies were performed in terms of electronic, ionic, and orientational polarizations using Debye equation. The relationship between the mechanical properties and the synthetic conditions of the silicate-silsesquioxane precursors was also investigated. The synthetic conditions of the low-k films have to be chosen to meet both the low orientational polarization and high mechanical properties requirements. In addition, we have investigated a new solution-based approach to the synthesis of semiconducting chalcogenide films for use in thin-film transistor (TFT) devices, in an attempt to develop a simple and robust solution process for the synthesis of inorganic semiconductors. Our material design strategy is to use a sol-gel reaction to carry out the deposition of a spin-coated CdS film, which can then be converted to a xerogel material. These devices were found to exhibit n-channel TFT characteristics with an excellent field-effect mobility (a saturation mobility of ${\sim}\;48\;cm^2V^{-1}s^{-1}$) and low voltage operation (< 5 V). These results show that these semiconducting thin film materials can be used in low-cost and high-performance printable electronics.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.207-214
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• 1993

Glass-ceramic monoliths with an ultra-low thermal expansion coefficient have been synthesized by the sol-gel technique using metal alkoxides as starting materials and dimethyl formamide as a drying control chemical additive. The ternary gels: $Li_2O\cdot Al_2O_3\cdot 2, 4 or $6SiO_2$ were obtained by hydrolysis and polycondensation reactions of metal alkoxides of silicon, aluminum and lithium. To produce cylindrical crack-free gel monoliths, excess water was used to the starting solutions and drying rates were controlled precisely to prevent cracking. In conversion process ,${\beta}$-eucryptite, $Li_2O\cdot Al_2O_3\cdot 3SiO_2$ and P-spodumene with ,${\beta}$-quartz solid solution phase were obtained by heating at the range of 750 ~$1000^{\circ}C$. Above $800^{\circ}C$, the ,${\beta}$-spodumene phase increased while ,${\beta}$-eucryptite phase decreased. The thermal expansion coefficient of the crystallized specimens were -15~ $+5{\times}{10^{-7}}/{\circ}C$ over the temperature range from room temperature to $600^{\circ}C$.