• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.7 no.3
• /
• pp.15-22
• /
• 2011

The chemistry factor and RTPTS margin for domestic reactor pressure vessel materials were analyzed by using the surveillance data which have been obtained from 8 nuclear power plants in Korea. The surveillance data have been used to assess the integrity of the pressure vessel under the pressurized thermal shock (PTS) event. The chemistry factor, which is determined by the Cu and Ni contents of vessel materials, is considered a proper tool to assess the $RT_{PTS}$. The chemistry factors, which were obtained from the surveillance data of domestic reactor pressure vessels, were investigated and compared with those of Regulatory Guide 1.99 in this study. Regressions for ${\Delta}RT_{NDT}$ were performed to expect the chemistry factor as a function of Cu and Ni, and to estimate $RT_{PTS}$ margin. The margin analysis was performed by comparing the regression graphs and standard deviations with those of Regulatory Guide 1.99. The standard deviations calculated by using the domestic surveillance data for base metal and welds are almost same as the standard deviations which are suggested on Regulatory Guide 1.99, Rev.2.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.12
• /
• pp.4201-4203
• /
• 2012

• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2511-2514
• /
• 2013

• Journal of the Korean Chemical Society
• /
• v.64 no.2
• /
• pp.119-129
• /
• 2020

For effective teaching-learning activities for students with diverse talents in science high schools, it is important for teachers to understand students' individual differences in perceiving and processing information in the natural world, depending on the students' various talents and subject characteristics. The purpose of this study is to examine the students' cognition of chemistry in science high school through correlations and factor analysis of mathematics/science achievement. In addition, this study attempted to examine the cognition of chemistry subject according to R&E classes. The main participants of the study were freshmen of G science high school (296 students) who entered after three times of curriculum reforms and new admission processes and the students in two other science high schools in Gyeongnam and Ulsan were included. The correlation and factor analysis were conducted by exploratory factor analysis by IBM SPSS Statistics 25 programs. The results of this study were as follows: First, in the correlation analysis between mathematics and science achievement, it was confirmed that the Pearson's coefficient of chemistry showed higher positive correlation coefficient than that of other science subjects. Second, in the factor analysis of mathematics and science achievements, it was found that the factor indicators were divided into two factors as logical-mathematical (mathematics and physics) and naturalistic (life science and earth science). Third, in the factor analysis, it was confirmed that the chemistry is recognized as the subject that requires both logical-mathematical and naturalistic intelligence. Finally, it was confirmed that students' cognitions of chemistry subject were found to differ according to the R&E classes. In other words, the participants of R&E chemistry class, unlike other students, were found to recognize chemistry as the subject that logical-mathematical intelligence is needed.

• Natural Product Sciences
• /
• v.27 no.2
• /
• pp.134-139
• /
• 2021

A new cipadesin limonoid, i.e. 3-epi-cipadonoid C (1), and a new tirucallane triterpene, i.e. hispidol B 3-palmitate (3), have been isolated from the seeds and fruit peels extract of Sandoricum koetjape, respectively. Along with these compounds the known limonoid, cipaferen G (2), and two pentacyclic triterpenes, bryonolic (4) and bryononic (5) acids, were also isolated. The strucrures of the new compounds were elucidated by the analysis of NMR and mass spectral data. Compounds 1 - 5 were evaluated as the inhibitor of receptor tyrosine kinases (EGFR, Epidermal Growth Factor Receptor; HER2, HER4, Human Epidermal growth factor Receptor 2, -4; IGFR, Insulin-like Growth Factor Receptor; InsR, Insulin Receptor; KDR, Kinase insert Domain Receptor; PDGFRα, and PDGFRβ, Platelet-Derived Growth Factor Receptor-α and -β). The results showed only 1 and 3 that have weak activity against InsR.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.1
• /
• pp.74-77
• /
• 1994

Rare earth elements (REE) were individual separated by applying the gradient elution via HPLC using ${\alpha}-hydroxyisobutyric$ acid (HIBA) as an eluent. However, the overlap of Y and Dy peaks was too severe to obtain the resolution of these two peaks. The target transformation factor analysis (TTFA) was applied to resolve the elution peaks of Y and Dy. [A]$_{raw}$ formed from the absorbances of mixed solution was factor analyzed. The abstract factor analysis(AFA) was used to determine the number of components that contributed to the poorly resolved peaks. The error theory in the AFA showed that the number of components was 2. The test vectors which correspond to pure component were selected from the standard solutions of Y and Dy. TTFA was accomplished by target testing. The results showed that the resolution of two peaks as well as the determination of Y and Dy were possible by the factor analysis.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.3
• /
• pp.367-370
• /
• 1993

• Biomolecules & Therapeutics
• /
• v.24 no.2
• /
• pp.184-190
• /
• 2016

Rosa rugosa Thunb, a deciduous shrub of the genus Rosa, has been widely used to treat stomach aches, diarrhoea, pain, and chronic inflammatory disease in eastern Asia. In recent years, our research team has extensively studied the Rosa rugosa flower extract, and specifically undertook pharmacological experiments which have optimized the extraction process. Our methods have yielded a standard extract enriched in phenolic compounds, named PRE. Herein, we expand our efforts and evaluated the anti-inflammatory activity of PRE on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. PRE significantly inhibited production of nitric oxide (NO), prostaglandin $E_2(PGE_2)$, tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and interleukin $1{\beta}$ (IL-$1{\beta}$), as well as expression of their synthesizing enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase2 (COX-2). Furthermore, PRE inhibited activity of mitogen-activated protein kinases (MAPK) as well as nuclear factor-kappa B (NF-${\kappa}B$) signaling pathway. Our findings are the first to explain the anti-inflammatory mechanism by PRE in LPS-stimulated macrophages. Given these results, we propose that PRE has therapeutic potential in the prevention of inflammatory disorders.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3405-3409
• /
• 2013

The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.12
• /
• pp.1801-1806
• /
• 2004

Ligand-based quantitative structure-activity relationship (QSAR) studies were performed on indolinones derivatives as a potential inhibitor of the protein tyrosine kinase of fibroblast growth factor receptor (FGFR) by comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) implemented in the SYBYL packages. The initial X-ray structure of docked ligand (Su5402) to FGFR was used to minimize the 27 training set molecules using TRIPOS force field. Seven models were generated using CoMFA and CoMSIA with grid spacing 2 ${\AA}$. After the PLS analysis the best predicted CoMSIA model with hydrophobicity, hydrogen bond donor and acceptor property showed that a leave-one out(LOO) cross validated value $({r^2}_{cv})^$ and non-cross validated conventional value $({r^2}_{ncv})^$ are 0.543 and 0.938, respectively.