• Journal of the Korean Ceramic Society
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• v.43 no.10 s.293
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• pp.595-600
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• 2006

The preparation of $\beta$-SiAlON powder by SHS in the system of $Si-Al-SiO_2-NH_4F(\beta-Si_3N_4)$ was investigated in this study. In the preparation of SiAlON powder, the effect of gas pressure, compositions such as Si, $NH_4F$, \beta-Si_3N_4$ and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $\beta$-SiAlON was $3Si+Al+2SiO_2+NH_4F$. The $\beta$-SiAlON powder synthesized in this condition was a single phase $\beta$-SiAlON with a rod like morphology.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1164-1170
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• 1999

The physicochemical characteristics of ${\beta}-glucan$ isolated from waxy and non-waxy barley were investigated. The hull-less waxy and non-waxy barley containing 6.5% and 5.3% of total ${\beta}-glucan$ respectively, were used as a starting material. The yield and ${\beta}-glucan$ content of crude ${\beta}-glucan$ from waxy barley was 5.54% and 62.9%, respectively, and those were higher than 3.34% and 59.2% from non-waxy barley. The crude ${\beta}-glucan$ purified with selective precipitation and enzymatic treatment to obtain the ${\beta}-glucan$ isolate of high purity (>99%). The total yield of purified ${\beta}-glucan$ from waxy and non-waxy barley was 4.46% and 2.59%, respectively. The surface appearance of the purified ${\beta}-glucan$ by scanning electron microscopy (SEM) showed randomly entangled multi-net structure of ${\beta}-glucan$ microfibrils. The melting temperature of ${\beta}-glucan$ from waxy and non-waxy barley measured by differential scanning calorimetry (DSC) was $184.6^{\circ}C$, and $180.3^{\circ}C$, respectively. DSC endotherm of ${\beta}-glucan$ solution showed 2 peaks near $68^{\circ}C$ and $84^{\circ}C$. Enthalpy of phase transition was higher in non-waxy ${\beta}-glucan$ than waxy ${\beta}-glucan$, and the intrinsic viscosity of ${\beta}-glucan$ solution from waxy barley was higher than that of non-waxy ${\beta}-glucan$. The pasting viscosity of barley starch with the purified ${\beta}-glucan$ determined by Rapid Visco-Analyzer was higher than that of barley starch without ${\beta}-glucan$, and the effect of ${\beta}-glucan$ on increasing the paste viscosity was greater in non-waxy barley starch.

• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.22-27
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• 1994

For the $\beta$=1 specimen with constant thickness, Crack growth rate is smoothly increasing in the a-N curve. On the other hand for $\beta$=2 specimen with various thickness, the inflection point is observed in crack growth rate near the thickness interface. da/dN before the inflection point is increased, and da/dN after the point is decreased, compared to the $\beta$=1 specimen. da/dN near the thickness interface is approached zero. The descending point was observed earlier as $\beta$ increased. Considering the relation between da/dN and λ, the crack propagation rates for the case of $\beta$ =1 incrased almost linearly, however, the crack propagation rates for $\beta$=2,3 decreased more rapidly near the thickness interface. Additionally, the decreased point in da/dN for $\beta$=3 is farther from the thickness interface than the case for $\beta$ =2.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.439-443
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• 1991

A strain of Streptomyces sp. isolated from soil was found to produce extra-cellular $\beta$-lactamase associated partially to the cell growth. The $\beta$-lactamase was purified from the culture supernatant through anmonium sulfate fractionation, ion-exchange chromatographies and gel filtration. The final purification fold and recovery yield were 57 and 6.2%, respectively. Molecular weight of the $\beta$-lactamase was estimated to be about 67, 000 by SDS-polyacrylamide gel electrophoresis. The optimal reaction condition was at pH 7-8 and at 35-$45^{\circ}C$. The $K_m$ and $V_{max}$ values of the enzyme for penicillin G were estimated to he 3 mM and $3\times 10^3$ $\mu\textrm{M}$/min/mg protein, respectively. The purified $\beta$-lactamase was classified to the class A enzyme hydrolyzing only penicillin.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.270-275
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• 2006

[ $2{\beta},\;3{\alpha}$ ], 23-trihydroxyrus-12-ene-28-oic acid was isolated from Trapa pseudoincisa S. et Z. It has a common structure of pentacyclic triterpenes and belongs to the amyrin ursolic acid group. The cytotoxic effect of this compound was investigated in human hepatoma cell line HepG2. $2{\beta},\;3{\alpha}$, 23-trihydroxyrus-12-ene-28-oic acid showed dose-dependent cytotoxicity in HepG2 cells. Confocal microscopy data showed that green fluorescence was increased in $2{\beta},\;3{\alpha}$, 23-trihydroxyrus-12-ene-28-oic acid treated-HepG2 cells in a time-dependent manner. $2{\beta},\;3{\alpha}$, 23-trihydroxyrus-12-ene-28-oic acid also increased the sub-G1 cell population of HepG2 cells as well as ladder-like DNA fragmentation. Taken together, our results indicate that $2{\beta},\;3{\alpha}$, 23-trihydroxyrus-12-ene-28-oic acid induced apoptosis in HepG2 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.2
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• pp.161-167
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• 1997

This study compares the subtypes of central beta adrenergic receptors (ARs) of brains of untreated rats with those of imipramine-treated rats. Beta adrenergic receptors were measured by quantitative autoradiography of the binding of $^3H$-dihydroalprenolol ($^3H$-DHA) in coronal sections of rat brain. Repeated treatment of rats with imipramine significantly reduced the binding of $^3H$-DHA to beta-1 AR in many brain areas, especially throughout the cerebral cortex, hippocampus, thalamus, and amygdala. Significant reductions of the binding of $^3H$-DHA to beta-2 AR were not found in any area of the brain. These data suggests that a selective down-regulation of beta-1 AR may be involved in the adaptive changes occurring after prolonged imipramine treatment.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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• pp.149-157
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• 2013

The octopus type oligo-hydroxypropylene glycol ${\beta}$-D-glucopyranosides were successfully synthesized in this studies: the sterospecific compound of allyl 2, 3, 4, 6-tetra-O-acetyl-${\beta}$-D-glucopyranosides (1) was deacetylated with NaOMe in MeOH lead to allyl-${\beta}$-D-glucopyranoside (2) which was perallylated and followed by hydroboration and subsequent oxidation afforded (3-hydroxy-propyl) 2, 3, 4, 6-tetraO(3-hydroxy-propyl)-${\beta}$-D-glucopyranoside (4). As a result, not only allylpropylene glycol ${\beta}$-D-glucopyranosides (5, 7, and 9) but also hydroxypropylene glycol ${\beta}$-D-glucopyranosides (6, 8, and 10) were synthesized by repeated sequential perallylation followed by hydroboration/oxidation.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.575-579
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• 1991

Reaction of 6${\beta}$-bromopenicillanic acid(4a) with p-nitrobenzylbromide, 3-bromophthalide, chloromethylpivalate and 1-chlorodiethylcarbonate afforded 6${\beta}$-bromopenicillanates(4b~4e). New ${\beta}$-lactam compound, 6-(carboxymethylthio)penicillanic acid(5a) and the other esters(5b~5e) were prepared by nucleophilic substitution reaction of 6${\beta}$-bromopenicillanic acid(4a) and the other esters(4b~4e) with thioglycolic acid.

• Communications for Statistical Applications and Methods
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• v.31 no.3
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• pp.263-277
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• 2024

This paper proposes new parameterizations of the tilted beta binomial distribution, obtained from the combination of the binomial distribution and the tilted beta distribution, where the beta component of the mixture is parameterized as a function of their mean and variance. These new parameterized distributions include as particular cases the beta rectangular binomial and the beta binomial distributions. After that, we propose new linear regression models to deal with overdispersed binomial datasets. These new models are defined from the proposed new parameterization of the tilted beta binomial distribution, and assume regression structures for the mean and variance parameters. These new linear regression models are fitted by applying Bayesian methods and using the OpenBUGS software. The proposed regression models are fitted to a school absenteeism dataset and to the seeds germination rate according to the type seed and root.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.407-411
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• 2007

Regulation of ${\beta}-xylosidase$ synthesis in Paenibacillus sp. DC-22 was studied to optimize the enzyme production. ${\beta}-Xylosidase$ synthesis of the Paenibacillus sp. DG-22 was observed to be regulated by carbon sources present in culture media. The synthesis of ${\beta}-xylosidase$ was induced by xylan and methyl ${\beta}-D-xylopyranoside$ (${\beta}MeXyl$) but slightly repressed by readily metabolizable monosaccharides. ${\beta}MeXyl$ was found to be the best substrate for the induction of ${\beta}$-xylosidase and the most effective induction was obtained at a concentration of 10 mg/ml. ${\beta}-Xylosidase$ production showed a cell growth associated profile with the maximum amount formed during the late exponential phase of growth. The presence of glucose and xylose decreased the level of ${\beta}-xylosidase$ activity indicating that its production was subjected to a form of carbon catabolite repression. SDS-PAGE and zymogram techniques demonstrated the induction by ${\beta}MeXyl$ and revealed the presence of one ${\beta}-xylosidase$ of approximately 80 kDa.