• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.344-348
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• 1999

To investigate hormetic effect of low dose ${\gamma}$-ray on the uptake of mineral nutrients in Chinese cabbage (Brassica campestris var. Hekjinju var. Surim and) and radish (Raphanus sativas var. Chung-un), seeds of these plants were irradiated with the dose of 1 to 10 Gy. Germination rate and dry weight were examined at pot experiment in greenhouse. Samples for analysis of mineral nutrient were harvested at 17 days and at 59 days after seedling and were analyzed by ICP. Brassica campestris varieties showed higher germination rate and dry weight production with increasing ${\gamma}$ ray dose. Dry weight of Hekjinju Surim and were 143% and 138% at 10Gy dose. respectively. There was no tendency in germination rate and dry weight production for Raphanus sativas var. Chung-un with ${\gamma}$-ray irradiation. The pattern of mineral nutrient content of these plants showed ${\gamma}$ or ${\delta}$ type of dose-reaction curve with no siginificant. This investigation suggests that the more results can be required to understand the hormetic effect of low dose ${\gamma}$ ray on the uptake of mineral nutrient for these plants.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.258-265
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• 1999

Entry into meiosis in the yeast Saccharomyces cerevisiae is regulated by two major factors: the cell type MATa/MAT${\alpha}$ and the nutriational state (starvation) of the cell. The two independent regulations act through IME1and IME2 expression to initiate meiosis. IME2 encodes a meiosis-specific protein kinase, and it enabled MATa/MAT${\alpha}$ diploid cells to undergo meiosis and sporulation. The PCR mutagenesis method was applied for the isolation of thermosensitive ime2 mutants. Among sixty two mutants isolated from the phenotype of defective spore formation under the restrictive temperature, three with the most easily observed temperature-sensitive phenotype (ts ${\cdot}$ime2-11, ts ${\cdot}$ime2-12 and ts ${\cdot}$ime2-13) were selected for further study. To understand the detailed functions of IME2, we examined the defects of these mutants in the early meiotic pathway including the premeiotic DNA replication and exhibited decreased level in meiotic recombination. These results suggest that the IME2 gene plays essential role in meiotic recombination pathway as well as premeiotic DNA replication. As the result of the IME2 overexpression in ${\Delta}$mre4. moreover, it was suggested that the IME2 and MRE4 genes act on the same pathway of initiation step in meiotic recombination.

• Journal of Pharmaceutical Investigation
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• v.31 no.2
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• pp.131-136
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• 2001

Tofisopam is a new type of tranquilizer valuable for the relief of anxiety and tension in a wide range of emotional disorders. Tofisopam has the therapeutic characteristics of a minor tranquilzer and a mild stimulatory effect. The purpose of the present study was to evaluate the bioequivalence of two tofisopam tablets, $Grandaxin^{TM}$ (Hwan In Pharmaceutical Co., Ltd.) and $Tofim^{TM}$ (Kyung Dong Pharmaceutical Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). Eighteen normal male volunteers, $23.11\;{\pm}\;2.83$ years in age and $65.43\;{\pm}\;7.64\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one tablet containing 50 mg of tofisopam was orally administered, blood was taken at predetermined time intervals and the concentrations of tofisopam in serum were determined using HPLC method with UV detector. The pharmacokinetic parameters such as $AUC_t$, $C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters. The results showed that the differences in $AUC_t$, C_{max}\;and\;T_{max}$ between two tablets based on the $Grandaxin^{TM}$ were -5.59%, 2.22% and -13.18%, respectively. Minimum detectable differences $({\Delta})$ at ${\alpha}=0.10$ and $1-{\beta}=0.8$ were less than 20% (e.g., 14.95% and 19.34% for $AUC_t\;and\;C_{max}$, respectively). The powers $(1-{\beta})$ at ${\alpha}=0.10$, ${\Delta}=0.2$ for $AUC_t$ and $C_{max}$ were 95.21% and 81.93%, respectively. The 90% confidence intervals were within {\pm}20%$ (e.g., $-15.64{\sim}4.45$ and $-10.77{\sim}15.21$ for $AUC_t\;and\;C_{max}$, respectively). Two parameters met the criteria of KFDA for bioequivalence, indicating that $Tofim^{TM}$ tablet is bioequivalent to $Grandaxin^{TM}$ tablet.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.89-94
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• 2008

We synthesized and investigated $(La_{0.75}Sr_{0.25})_{1-x}FeO_{3-\delta}$ perovskite oxides having different stoichiomety (x = 0, 0.02, 0.04, 0.06, 0.08) as cathode materials. SEM images and XRD patterns reveal that the synthesized powder has uniform size distribution and high degree of crystallinity. The electrochemical performances of the synthesized powders were investigated by AC impedance spectroscopy. Both the electric conductivity and the electrochemical performance showed the highest properties at the stoichiometry x = 0.02. Finally, we concluded that the variation of A-site deficiency results in the variation of the amount of oxygen vacancy and micro structure, which leads to the variation of electric conductivity and polarization resistance.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1500-1508
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• 2013

Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139, has obvious antirheumatic arthritis activity in vivo, and its biosynthesis gene cluster (ste), consisting of 27 open reading frames, has been identified. This paper reports our study of the gene functionality of ste8, the predicted protein product of which is homologous to some bacterial chain length determinant Wzz proteins. For characterization of Ste8, ste8 was cloned and expressed in the mutant strain E. coli 086:H2 (${\Delta}wzz$). The functional complementation of wzz by ste8 was demonstrated by the restoration of wild-type lipopolysaccharide biosynthesis and increased levels of serum resistance of E. coli 086:H2 (${\Delta}wzz$) (pET30a-ste8). To examine the function of ste8 in ebosin biosynthesis, the gene was knocked out with a double crossover via homologous recombination. The molecular weight of the ebosin derivative EPS-8m produced by the mutant Streptomyces sp. 139 ($ste8^-$) was much lower than that of ebosin, and the binding activity of EPS-8m for IL-1R decreased significantly compared with ebosin. These results demonstrate that ste8 encodes a chain length determinant (Wzz) that functions in ebosin biosynthesis.

• Food Science and Preservation
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• v.23 no.4
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• pp.538-546
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• 2016

Kochujang was prepared by replacement of rice (25%, control) with pumpkin or purple sweet potato by 0. 5, 10, and 15% (total addition ratio of rice and sweet potato=25% of sample). Effects of the addition of sweet potato on physiochemical properties of fermented Kochujang were investigated. Viable cells of yeast decreased in the sweet potato-added Kochujang at the later stage of fermentation, while there was no significant difference in the number of bacteria among the test groups. As the addition ratio sweet potato increased, ${\alpha}$-amylase activity increased while protease activity decreased. Hunter L, a, and b values of Kochujang prepared with purple sweet potato were lower than those with pumpkin sweet potato. Changes in ${\Delta}E$ value was greater in Kochujang prepared with pumpkin sweet potato than that with purple sweet potato. Oxidation-reduction potential and water activity were higher in sweet potato-Kochujang than control, but reducing sugar content was higher in control. Alcohol and amino-type nitrogen contents were higher in Kochujang prepared with pumpkin sweet potato than that with purple sweet potato, but it was not significant. Overall sensory acceptability was highest in Kochujang prepared with 10% of purple sweet potato while that with 15% pumpkin sweet potato was the least preferred.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.91-98
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• 2011

Recently, the usage of elastic paving using EPDM Chip instead of pedestrian sidewalk blocks or permeable concrete used mostly for pedestrian walk, trails and in parks has been increassed as it can absorb impact during walking and produce wide range of colors and designs. However, the properties of EPDM Chip including elasticity and durability are decreased when exposed to ultraviolet ray and scenic paving functions through various colors are lowered due to the yellowing phenomenon. In this study, ultraviolet ray accelerated weathering test has been conducted to analyze the color changes in EPDM Chip and polyurethane resin, which are the main ingredients of elastic paving, when exposed to ultraviolet ray. The color differences are quantitatively analyzed through the color value coordination of the colored space by using the color difference scheme. The experimental results show that the color changes in BL polyurethane resin which is used most frequently at present was larger than that of EPDM Chip. Moreover, the total color difference, ${\Delta}E$, of BC polyurethane resin are 3.162 on the $14^{th}$ day of commencement of acceleration, which is 6 times greater color change resistance against ultraviolet ray than that of BL polyurethane resin with total color difference of 20.639. Therefore, the usage of BC polyurethane resin, which is manufactured to have chain-type molecular structure by using the isocyanate as the HMDI at the time of producing polymer, as binder in elastic paving with EPDM Chip is found to be a highly efficient method of restraining the color changes due to the ultraviolet ray.

• Composites Research
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• v.29 no.4
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• pp.145-150
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• 2016

Polyvinylidene fluoride (PVDF) as a representative polymer with the piezoelectric property has been studied since the 1960s. Crystalline structure of poly(vinylidene fluoride) polymer is composed of five different crystal structure of the polymer as a semi-crystalline. Among the various crystal structures, ${\beta}-type$ crystal exhibits a piezoelectricity because the permanent dipoles are aligned in one direction. Generally ${\beta}-form$ crystal structure can be obtained through the transformation of the ${\alpha}-form$ crystal structure by the stretching and it can increase the amount through the after treatment as poling process after stretching. ${\beta}-form$ crystal structure the PVDF fibers produced by wet spinning is formed through a diffusion mechanism of a polar solvent in the coagulation bath. However, it has a disadvantage that the diffusion path of the solvent remains as pores in the fiber because the fiber solidification occurs simultaneously with the diffusion of the polar solvent. These pores play a role in reducing effect of poling process owing to effect of disturbances acting on the polarization by the electric field. In this work, the drying method using the microwave was introduced to remove more effectively the residual solvent and the pore within PVDF fibers produced through wet-spinning process and piezoelectric PVDF fibers was produced by transformation of the remaining ${\alpha}$ form crystal structure into ${\beta}-crystal$ structure through the stretching process.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.1-14
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• 2015

The standard GARCH model imposing symmetry on the conditional variance, tends to fail in capturing some important features of the data. This paper, hence, introduces the models capturing asymmetric effect. They are the EGARCH model and the GJR model. We provide the systematic comparison of volatility models focusing on the asymmetric effect of news on volatility. Specifically, three diagnostic tests are provided: the sign bias test, the negative size bias test, and the positive size bias test. This paper shows that there is significant evidence of GARCH-type process in the data, as shown by the test for the Ljung-Box Q statistic on the squared residual data. The estimated unconditional density function for squared residual is clearly skewed to the left and markedly leptokurtic when compared with the standard normal distribution. The observation of volatility clustering is also clearly reinforced by the plot of the squared value of residuals of export volume and values. The unconditional variance of both export volumes and export value indicates that large shocks of either sign tend to be followed by large shocks, and small shocks of either sign tend to follow small shocks. The estimated export volume news impact curve for the GARCH also suggests that $h_t$ is overestimated for large negative and positive shocks. The conditional variance equation of the GARCH model for export volumes contains two parameters ${\alpha}$ and ${\beta}$ that are insignificant, indicating that the GARCH model is a poor characterization of the conditional variance of export volumes. The conditional variance equation of the EGARCH model for export value, however, shows a positive sign of parameter ${\delta}$, which is contrary to our expectation, while the GJR model exhibits that parameters ${\alpha}$ and ${\beta}$ are insignificant, and ${\delta}$ is marginally significant. That indicates that the asymmetric volatility models are poor characterization of the conditional variance of export value. It is concluded that the asymmetric EGARCH and GJR model are appropriate in explaining the volatility of export volume, while the symmetric standard GARCH model is good for capturing the volatility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1156-1164
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• 2010

Structured lipids (SLs) were synthesized by enzymatic interesterification with evening primrose oil (EPO) and rice bran oil (RBO) in a batch-type reactor. The interesterification was performed using a water shaker for 24 hr at $55^{\circ}C$. Mixing speed was set at 200 rpm and Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, 10% by weight of total substrates) was used as a biocatalyst. Rice bran oil and evening primrose oil were interesterified with various molar ratios (RBO : EPO, 1:3, 1:4, and 1:5 mol/mol). Reversed-phase high performance liquid chromatography connected with evaporative light-scattering detector was performed to separate the triacylglycerol (TAG) species of SLs. In the fatty acid analysis, $\gamma$-linolenic acid (7.9 mol%), linoleic acid (67.3 mol%) and oleic acid (13.2 mol%) were the most abundant fatty acids in the SLs. During 24 hr reaction, most of the reaction occurred within 3 hr. TAG compositions, tocopherols and phytosterols were also analyzed. In the TAG species analysis, LLL (ECN=42, L=linoleic acid) dramatically decreased when the reaction time increased.