• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.269-273
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• 2006

Potassium Sorbate (PS) is a potassium salt version of sorbic acid, which has antimicrobial and fungistatic features in foods. Therefore, PS is used as a food preservative against fungi and mold. PS has been found to be non-toxic even when taken in large quantities given its trait to be broken down in the body into water and carbon dioxide. Gap Junctional Intercellular Communication (GJIC) is essential in the maintenance of tissue homeostasis during development and differentiation. This study was made of the effects of PS on GJIC in WB-F344 rat liver epithelial (WB) cells. We found dramatic decrease of cell viability in time- and dose-dependent manners when WB cells were treated with PS. The effect of PS on GJIC is strong inhibition, and it took place in parallel with a hyperphosphorylation of connexin 43 expression. The finding that PS interferes with gap junction functionality should be considered with respect to the mechanism of PS-induced hepatotoxicity.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.459-469
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• 2022

This study aims to provide basic data for the development of teaching methods to improve the performance confidence of performing core basic nursing skills in nursing students while availing of online education owing to COVID-19. Data were collected from 146 students in the Department of Nursing at N University located in C city. The collected data was analyzed using descriptive statistics, difference, correlation analysis, and multiple regression by using SPSS 23.0 program.. The subjects' performance confidence of core basic nursing skills was dependent on self-directed learning readiness (r=.368, p<.001), intrinsic goal motivation (r=.232, p=.005), extrinsic goal motivation (r=.344, p<.001), task value (r=.237, p=<.001), control of learning beliefs (r=.262, p=<.001), and self-efficacy for learning and performance (r=.443), p<.001) with a significant positive correlation. The results indicate that the factors influencing the subjects' performance confidence of core basic nursing skills were the 4th grade (β=0.413, p<.001), extrinsic goal motivation (β=0.307, p<.001), and self-efficacy for learning and performance (β=0.316, p=.005), and the explanatory power was 35.8% (F=8.354, p<.001). The research results showed that it is necessary to develop and apply various online-centered teaching and learning methods to increase the extrinsic goal motivation and self-efficacy for learning and performance of nursing students to enhance their performance confidence of core basic nursing skills. This will serve as a basis for preparing effective online centered nursing education strategies to improve performance confidence of core basic nursing skills.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.335-344
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• 2016

The purpose of the study was to investigate the effect of stress, social support, and self-esteem on depression in female students. A self-reported questionnaire was completed by 249 females students from November to December 2015. The study instruments comprised stress, social support, self-esteem, and depression. The data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and hierarchial multiple linear regression using SPSS/WIN 18.0 program. Depression was closely related to school year(F=7.03, p<.001), health status(F=15.19, p<.001), major satisfaction(F=18.02, p<.001), and student activity(t=1.98, p=.049). The significant factors influencing depression were stress(${\beta}=.45$, p<.001), self-esteem(${\beta}=-.34$, p<.001), social support(${\beta}=-.14$, p=.004), major satisfaction(${\beta}=-.11$, p=.018). To decrease depression, it is necessary to develop a program coping with stress and increasing the self-esteem and social support. Thus, it will be able to enhance the mental health of female students.

• Nuclear Engineering and Technology
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• v.26 no.3
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• pp.337-344
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• 1994

Enthalpy rise hot channel factor($F_{\Delta{H}}$$^{N}$) is one of the most limiting constraints in determining the fuel loading pattern(LP) for PWR's. In order to enhance the LP design flexibility without any changes of not only basic fuel specifications but also Technical Specifications and Operation Procedures, we apply the enrichment zoning concept to Westinghouse designed PWR's to flatten the rod power distributions within the fuel assembly and thus to reduce $F_{\Delta{H}}$$^{N}$. Enrichment zoning is described that each assembly consists of two different enrichment fuels ; the lower enriched fuels are located in positions which are expected to have the higher rod power and vice versa for the higher enriched fuels. As a result of unit assembly calculations to flatten the rod power distribution within the assembly, the appropriate enrichment difference is found to be 0.3~0.4w/o. Through core depletion calculations for the 18-month cycle of Kori Unit 4, the $F_{\Delta{H}}$$^{N}$ behavior in core with the enrichment zoning concept is investigated. A comparison with the reference case without the enrichment zoning results in a reduction in $F_{\Delta{H}}$$^{N}$ of approximately 1.5%.TEX>H/$^{N}$ of approximately 1.5%.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.344-351
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• 1987

Kinetic studies on the complexing of $[Mo_2O_4(H_2O)_6]^{2+}$ with thiocyanate have been carried out using the spectrophotometric method. The observed rate constant is given by, $k_{obsd}=\{\\k_0+k_H[H^+]\}\;[SCN^-]^2+k_r$. At $25^{\circ}C$ and ionic strength of 2.84 the values of $k_f\;and\;k_r\;are\;5.96{\pm}0.35\;M^{-2}s^{-1}\;and\;(5.45{\pm}4.77){\times}10^{-4}s^{-1}$, respectively. Activation parameters from data at $20^{\circ}$∼$35^{\circ}C\;are\;{\Delta}H^*=38.04{\pm}5.31kJmol^{-1}\;and\;{\Delta}S^*=-172.69JK^{-1}mol^{-1}$. The mechanisms are discussed.

• YAKHAK HOEJI
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• v.50 no.5
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• pp.338-344
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• 2006

A novel series of 4-senecioyloxymethyl-6,7-dimethoxycoumarin, isolated from Crinum latifolium, was prepared by reacting 4-bromomethyl or 4-bromomethyl-6,7- dimethoxycoumarin with various carboxylic acids and examined for their anti-angiogenic activities in human umbilical vein endothelial cells (HUVECs). Among them, 4e, 4f, 4g and 4i with noncyclic moiety exhibited potent anti-angiogenic activity. However, compounds with cyclic moiety such as phenyl, pyridinyl, thiophenyl and furanyl group did not exhibit any anti-angiogenic activity. Also, compounds 4f and 4g which exhibited strong anti-angiogenic activity in a dose-dependent manner showed antitumor activity.

• Environmental Mutagens and Carcinogens
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• v.19 no.2
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• pp.89-94
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• 1999

Cell proliferation and c-Jun expression pattern in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate, and genotoxic carcinogen 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) were investigated to see whether differential effects of genotoxic and non-genotoxic carcinogens on the development of neoplastic foci may be related to differential effect on cell proliferation. Male F344 rats were initially given a single intraperitioneal injection of diethylnitrosamine (200 mg/kg body weight), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CE or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to the two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed until 8 weeks. Cell proliferation was examined by immunohistochemical staining of bromodeoxyuridine and c-Jun expression was determined by northern blotting. The increase of cell proliferation rate after PH was significant in the rats fed 0.05% IQ and continued until 8 weeks, while the increase was not significant in the rats fed phenobarbital and clofibrate compared to that in the rats fed control diet. mRNA level of c-Jun in the liver treated with IQ was about 7 fold higher than that of control and peak at 5 hours after rH. In the liver treated with CE, mRNA level of c-Jun was 3-4 fold higher than that of control and the highest level of mRNA of c-Jun was seen at 24 hours after PH. These results show that differential effects of genotoxic and non-genotoxic carcinogens on the development of neoplastic foci may be related to differential effect on cell proliferation pattern.

• Development and Reproduction
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• v.23 no.4
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• pp.333-344
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• 2019

In vertebrate reproductive system, estrogen receptor (ER) plays a pivotal role in mediation of estrogenic signaling pathways. In the present study, we report the cDNA cloning, expression analysis, and transcriptional activity of ERβ1 subtype from medaka Oryzias dancena. The deduced O. dancena ERβ1 (odERβ1; 519 amino acids) contained six characteristic A/B to E/F domains with very short activation function 2 region (called AF2). A phylogenetic analysis indicated that odERβ1 was highly conserved among teleost ERβ1 subgroup. A conventional RT-PCR revealed that the odERβ1 transcripts were widely distributed in the multiple tissues, the ovary, brain, gill, intestine, kidney, and muscle. Further, the relatively higher odERβ1 expressions in the ovary and brain were clearly reproduced in RT-qPCR assay. When HA-fused odERβ1 expression vector was transfected into HEK293 cells, an immunoreactivity for odERβ1 was mainly detected in the nucleus part. Finally, an estrogen responsive element driven luciferase reporter assays demonstrated that the transcriptional activity of odERβ1 significantly increased by estradiol-17β (E2) in a dose dependent manner (p<0.05). However, fold-activation of odERβ1 in the presence of E2 was markedly weak, when it compared with those of O. latipes ERβ1. Taken together, these data suggest that odERβ1 represents a functional variant of teleost ERβ subtype and provides a basic tool allowing future studies examining the function of F domain of ERβ1 subtype and expanding our knowledge of ERβ evolution.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.7
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• pp.344-348
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• 2006

The effect of x on microwave dielectric properties of the $(1-x)Mg_4Ta_2O_9-x(TiO_2,\;CaTiO_3,\;SrTiO_3)$ ceramics for microwave components were investigated. All spcecimens prepared by the conventional mixed oxied method and sintered at $1450^{\circ}C$. Microwave dielectric properties of the $(1-x)Mg_4Ta_2O_9-xTiO_2$ ceramics were influenced by $MgTi_2O_5$ phase. Also the microwave dielectric properties of the $(1-x)Mg_4Ta_2O_9-x(TiO_2,\;CaTiO_3,\;SrTiO_3)$ ceramics were dominated with an addition of $CaTiO_3\;and\;SrTiO_3$. The dielectric constant $(\varepsilon_r)$, quality factor $(Q{\times}f_r)$ and temperature coefficient of the resonant frequency $(TCRF,\;\tau_f)$ of the $(1-x)Mg_4Ta_2O_9-x(TiO_2,\;CaTiO_3,\;SrTiO_3)$ ceramics were $12.96\sim70.98,\;5,132\sim186,410GHZ$ and $-35.82\sim+75.96ppm/^{\circ}C$, respectively, and depend on x and addition materials.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.363-369
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• 1998

Glutathione S-transferase placental form (GST-P) positive foci development and its expression in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate (CF), and genotoxic carcinogen 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) were investigated as a measure of carcinogenic potential of these chemicals. Male F344 rats were initially given a single intraperitioneal injection of diethyinitrosamine (200 mg/kg), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CF or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed at 8 weeks or 52 weeks, and liver tissues were examined for immunohistochemical staining of GST-P positive foci. The numbers (No./$cm^2$) and areas ($mm^2$/ $cm^2$) of GST-P positive foci were increased by IQ or PB, but were decreased by CF compare to the control. Consistent with the development of GST-P positive foci, a time-related increase in the expression of GST-P mRNA was found in the rats treated with IQ, whereas CF decreased it. The incidence of hepatocellular carcinoma at 52 weeks was increased by all three chemicals. These results show that PB and IQ induced GST-P positive foci, but the peroxisome proliferator CF did not, which suggest that the prediction of carcinogenic potency based on the development of prenoplastic foci may cause false negative in a particular category compounds like peroxisome proliferators.