• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.54-59
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• 1992

The characteristics of endogenous and exogenous ${\beta}-galactosidase\;({\beta}-Galase)$ produced from L. acidophilus were investigated as one of the serial studies on the fermentation of Chinese cabbage kimchi using L. acidophilus. Apparent molecular weight of endogenous and exogenous of the ${\beta}-Galase$ were investigated to be 550,000 and 740,000 daltons by the method of gel filtration and Km values of the both enzymes were 1.67mg/ml, 1.33mg/ml and $V_{max}$ were $8.5\;{\mu}\;mol/mg/30min.$, $2.65\;{\mu}\;mol/ml/30min.$, respectively. The optimum pH of the enzymes were 7 and 8, respectively. The optimum temperatures and salt concentrations of the both enzyme were the same and appeared to $30^{\circ}C$and$4{\sim}5%$, respectively. The activities of the endogenous and exogenous ${\beta}-Galase$ were decreased by increasing of temperature from $60^{\circ}C$to$90^{\circ}C$ and the decreasing rate of the enzyme activities on the processing of the heating times showed high at first 2 minutes of heating.

• Korean Journal of Materials Research
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• v.20 no.2
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• pp.55-59
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• 2010

$Na^+$ ion conductivity can be improved by the substitution of an Mg atom for an Al atom to form a nonstoichiometric $Na^+$ $\beta$-alumina. We performed a first principles study to investigate the most stable substitution site of an Mg atom and the resulting structural change of the nonstoichiometric $Na^+$ $\beta$-alumina. Al atoms were classified as four different layers in the spinel block that are separated by conduction planes in the nonstoichiometric $Na^+$ $\beta$-alumina. The substitution of an Mg atom for an Al atom at a tetragonal site was more favorable than that at an octahedral site. The substitution in the spinel block was more favorable than that close to the conduction plane. This result was well explained by the volume changes of the polyhedrons, by the standard deviation of the Mg-O distance, and by the comparison with bulk MgO structure. Our result indicates that the most preferable site for the Mg atom was the tetrahedral site at the spinel block in the nonstoichiometric $Na^+$ $\beta$-alumina.

• Metals and materials international
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• v.24 no.6
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• pp.1359-1368
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• 2018

The mechanical properties and microstructure evolution of Mg-8Li-3Al-1Y alloy undergoing different rolling processes were systematically investigated. X-ray diffraction, optical microscope, scanning electron microscopy, transmission electron microscopy as well as electron backscattered diffraction were used for tracking the microstructure evolution. Tensile testing was employed to characterize the mechanical properties. After hot rolling, the $MgLi_2Al$ precipitated in ${\beta}-Li$ matrix due to the transformation reaction: ${\beta}-Li{\rightarrow}{\beta}-Li+MgLi_2Al+{\alpha}-Mg$. As for the alloy subjected to annealed hot rolling, ${\beta}-Li$ phase was clearly recrystallized while recrystallization rarely occurred in ${\alpha}-Mg$ phase. With regard to the microstructure undergoing cold rolling, plenty of dislocations and dislocation walls were easily observed. In addition, the microstructure of alloys subjected to annealed cold rolling revealed the formation of new fresh ${\alpha}-Mg$ grains in ${\beta}-Li$ phase due to the precipitation reaction. The mechanical properties and fracture modes of Mg-8Li-3Al-1Y alloys can be effectively tuned by different rolling processes.

• KSBB Journal
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• v.11 no.5
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• pp.565-571
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• 1996

Medium optimization for ${\beta}$-mannanase production by Aspergillus oryzae ATCC 2114 was performed. Effect of carbon source (locust bean gum) concentration on ${\beta}$-mannanase production was investigated. Above 20 g/L locust bean gum, a lag time for ${\beta}$-mannanase production was appeared because high concentration of locust bean gum caused high viscosity which made the mixing of medium poor. As the locust bean gum concentration in the medium increased, ${\beta}$-mannanase activity and cell growth increased proportionally. Effect of various nitrogen sources on ${\beta}$-mannanase production was also studied. (NH4)2SO4 and malt extract were the most effective for ${\beta}$-mannanase production among the inorganic nitrogenous compounds and organic nitrogen nutrients. Inorganic compounds such as KH2SO4, NaCl, Na2CO3, and MgSO4, on ${\beta}$-mannanase production were optimized for ${\beta}$-mannanase production. Locust bean gum of 10 g/L, malt extract of 3 g/L, (NH4)2SO4 of 2 g/L, KH2SO4, of 10 g/L were selected as the optimal medium. Culture in a fermentor by using the optimal medium was carried out. Lag time of ${\beta}$-mannanase production was shorter due to the better mixing of the fermentor. The maximum ${\beta}$- mannanase activity of 9.7 unit/mL and specific ${\beta}$-mannanase activity of 1.9 unit/mg-cell could be obtained at 27 hours and the productivity of ${\beta}$-mannanase was 0.36 unit/mL$.$h.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.4
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• pp.185-190
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• 2014

The influences of small amount of Sn addition on microstructure and creep resistance of AZ91-0.4%Ca alloy have been investigated. The microstructure of the AZ91-0.4%Ca alloy was characterized by ${\alpha}$-(Mg) dendrite cells surrounded by eutectic ${\beta}(Mg_{17}Al_{12})$ and $Al_2Ca$ phases. The 0.5%Sn addition resulted in the formation of rod-shaped CaMgSn particles with the extinction of $Al_2Ca$. The Sn-containing alloy exhibited better creep resistance below $175^{\circ}C$, but the tendency was reversed above $200^{\circ}C$. The reason was discussed in relation to the change in thermal stability of ${\beta}$ phase in response to the Sn addition.

• Food Engineering Progress
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• v.14 no.4
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• pp.292-298
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• 2010

Wheat germ contains the glycosylated forms of 2-methoxy-p-benzoquinone (2-MBQ) and 2,6-dimethoxy-p-benzoquinone (2,6-DMBQ), both of which have antimicrobial and immunostimulatory effects. Conversion of glycosylated 2-MBQ and 2,6-DMBQ to their more functional unglycosylated forms requires enzymatic action of $\beta$-glucosidase. We investigated the applications of lactic acid bacteria and yeast that produce $\beta$-glucosidase as starters for production of unglycosylated 2-MBQ and 2,6-DMBQ from wheat germ. Lactobacillus zeae and Pichia pijperi were selected through $\beta$-glucosidase enzyme assays for 37 yeast strains and five strains of lactic acid bacteria. Lb. zeae was more efficient than P. pijperi at producing 2-MBQ and 2,6-DMBQ from wheat germ. After 48 hr of fermentation with a mixed culture of Lb. zeae and P. pijperi, the concentration of 2-MBQ was 0.46${\pm}$0.07 mg/g, indicating an approximately 1.6-fold higher concentration than that obtained by pure culture of Lb. zeae. However, the concentration of 2,6-DMBQ was not significantly enhanced by fermentation with a mixed culture of Lb. zeae and P. pijperi.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.73-78
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• 2004

The effect of supplemental yellow ${\beta}$-8-Apo-carotenoic acid ethyl ester (ACA) (0~300mg/kg feed) on its accumulation in each body part of laying hens and the pigmentation in egg yolk was determined. The chickens used in this study were 78-wk-old ISA brown laying hens. ACA significantly affected the color of the bodies of laying hens. The yellowness ($b^*$) but not the redness ($a^*$) and, the lightness ($L^*$) of the skin, and muscle as measured by a colorimeter significantly (P < 0.05) increased when ACA was fed at 50~100 mg/kg feed. Egg yolk color was also significantly affected by feeding ACA longer than 2 days (P < 0.05) at the levels higher than 50 mg/kg feed. Conclusively, ACA is recommended for improving yellowness of skin.

• Biomolecules & Therapeutics
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• v.21 no.3
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• pp.204-209
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• 2013

Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor receptor superfamily. It usually functions in bone remodeling, by inhibiting osteoclastogenesis through interaction with a receptor activator of the nuclear factor ${\kappa}B$ (RANKL). Transglutaminases-2 (Tgase-2) is a group of multifunctional enzymes that plays a role in cancer cell metastasis and bone formation. However, relationship between OPG and Tgase-2 is not studied. Therefore, we investigated the involvement of 12-O-Tetradecanoylphorbol 13-acetate in the expression of OPG in MG-63 osteosarcoma cells. Interleukin-$1{\beta}$ time-dependently induced OPG and Tgase-2 expression in cell lysates and media of the MG-63 cells by a Western blot. Additional 110 kda band was found in the media of MG-63 cells. 12-O-Tetradecanoylphorbol 13-acetate also induced OPG and Tgase-2 expression. However, an 110 kda band was not found in TPA-treated media of MG-63 cells. Cystamine, a Tgase-2 inhibitor, dose-dependently suppressed the expression of OPG in MG-63 cells. Gene silencing of Tgase-2 also significantly suppressed the expression of OPG in MG-63 cells. Next, we examined whether a band of 110 kda of OPG contains an isopeptide bond, an indication of Tgase-2 action, by monoclonal antibody specific for the isopeptide bond. However, we could not find the isopeptide bond at 110 kda but 77 kda, which is believed to be the band position of Tgase-2. This suggested that 110 kda is not the direct product of Tgase-2's action. All together, OPG and Tgase-2 is induced by IL-$1{\beta}$ or TPA in MG-63 cells and Tgase-2 is involved in OPG expression in MG-63 cells.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.11-15
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• 1994

The TSEE characteristics of LiF(Mg,Cu,Na,Si)phosphor for gamma and beta rays are described. The TSEE glow curve of this phosphor showed 5 peaks in the range from $20^{\circ}C$ to $400^{\circ}C$ and its main peak appeared at $240^{\circ}C$. The sensitivity of the phospor for $^{60}Co$ gamma rays was about 450counts/mR. TSEE energy dependence for various beta radiation was nearly constant (${\pm}10%$) in the mean beta particle energy range from 0.02MeV to 0.8MeV. The efficiency of TSEE of the phosphor for beta radiation was $(2{\sim}15){\times}10^{-3}$.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.240-244
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• 1985

Curde $\beta$-amylase was prepared by frationation of the water extracts from Korean ginseng, Panax Ginseng C.A. Meyer, with 0.2-0.6 saturation of ammonium sulfate. The enzyme showed the typical properties of $\beta$-amylase, producing only maltase from starch. The enzyme preparation also showed no maltase activity. The enzyme was stable at the pH 5-9 and at the temperature below $40^{\circ}C$. The enzyme showed the optimum pH at 5.0 and the optimum temperature at $35^{\circ}C$. Its activities had proportional relations with substrate concentration below 12 mg%, showing Km V slues of 4.76 mg%. The enzyme was inhibited by $Ag^{+}$, $Hg^{++}$, $Cd^{++}$, $Cu^{++}$,$ Al^{3+}$, and $Fe^{3+}$.