• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1702-1708
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• 2002

The synthesis and catalytic application of a new class of a new class of planar chiral ferrocenes, 1,2-ferrocenediylazaphosphinines (1 and 2) are described. They are powerful ligands for the copper(I)-catalyzed asymmetric cyclopropanation of a range of alkenes with diazo esters to exhibit an exceptionally high degree of diastereoselectivity(~100% de) in favor of trans isomers, regardless the structure of the olefins and the diazo compounds. Comparative studies between 1 and 2 reveal that the former works better in terms of diastereocontrol. In contrast, however, enantioselectivity is low with both 1 and 2 as a whole although, in certain cases with a proper combination of the olefin and the diazo ester, high optical yields (up to 100% ee) can be achieved. Other reaction parameters such as the reaction temperature and the structure of the ligand do exhibit some influence, although infinitestimal, on both chemical and optical yields.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.845-850
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• 2014

The rapid development of shotgun proteomics is paving the way for extensive proteome profiling, while providing extensive information on various post translational modifications (PTMs) that occur to a proteome of interest. For example, the current phosphoproteomic methods can yield more than 10,000 phosphopeptides identified from a proteome sample. Despite these developments, it remains a challenging issue to pinpoint the true phosphorylation sites, especially when multiple sites are possible for phosphorylation in the peptides. We developed the Phospho-UMC filter, which is a simple method of localizing the site of phosphorylation using unique mass classes (UMCs) information to differentiate phosphopeptides with different phosphorylation sites and increase the confidence in phosphorylation site localization. The method was applied to large scale phosphopeptide profiling data and was demonstrated to be effective in the reducing ambiguity associated with the tandem mass spectrometric data analysis of phosphopeptides.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.33-38
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• 2014

In the course of work on new pharmacologically active antimicrobial agents, we have reported the synthesis of a new class of structurally novel derivatives, incorporating two bioactive structures, a benzothiazole and thiazolidin-4-one, to yield a class of compounds having interesting antimicrobial properties. The antimicrobial properties of the synthesized compounds were investigated against bacteria (Staphylococcus aureus and Escherchia coli) and fungi (Candida albicans and Aspergillus niger) using serial plate dilution method. The structure of the synthesized compounds have been established by elemental analysis and spectroscopic data.

• Mass Spectrometry Letters
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• v.9 no.4
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• pp.110-114
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• 2018

Since accumulation of chemicals in deciduous teeth can occur from the second trimester of fetal development to shedding, a deciduous tooth has been considered as an attractive biomatrix for estimating individual chemical exposures recently. Therefore, detection of organic chemicals from teeth has received an increasing attention in exposomics research. Most previous studies on organic chemical analysis of teeth not only focused on a few targeted chemicals but also ignored potential contaminants from an enamel surface or a dental pulp. Recently, our group started developing a multi-class organic analysis method for deciduous teeth and tried to find a proper incubation condition of tooth materials. Our results showed that incubation with methanolic HCl provided the best performance among tested.

• Journal of the Korean Chemical Society
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• v.66 no.3
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• pp.218-227
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• 2022

The purpose of this study is to analyze the opinions of students by using the text mining to the good points and improvements among the descriptive course evaluation written by the students who participated in the university chemistry laboratory class, and to derive the improvement for the class. We analyzed the frequency of occurrence, co-occurrence and network of key words. As a result of the study, in the network of good points in the class, the most frequent mentions were made between class and professor, along with explanation, understanding, student, passion, fun, TA, experiment, help, etc. In the network of improvements in the class, the most frequent mentions were made between class and student, along with professor, content, explanation, exam, wish, experiment, understanding, difficult, thought, problem, etc. In other words, the students suggested the opinion that the contents of the class were well understood and that they felt fun and satisfied with the experimental process due to 'easy and detailed explanation' and 'TA's assistance' as good points of the class. On the other hand, the students suggested the negative opinions that the understanding and concentration in the class was decreased due to 'difficulty of content and exam', 'excessive assignments', and 'class environment' as improvements of the class.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.203.2-203
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• 1997

No Abstract, See Full Text

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2893-2894
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• 2011

• Journal of The Korean Association For Science Education
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• v.29 no.6
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• pp.653-665
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• 2009

The purpose of this research is to estimate the chemistry teacher's perceptions of Chemistry I course based on the 7th national curriculum through actual class teaching situations and interviews and teaching guidance of an actual class through a lesson and an interview. For this research, four chemistry teachers who have had an experience teaching the chemistry I course were selected. As the results of the research show, chemistry teachers had the correct understanding of the purpose of the Chemistry I course, but they were teaching the concepts of Chemistry II . They thought the reason for the teaching was the national scholastic aptitude test. But according to analysis, the contents of the previous tests were hardly beyond the limit of Chemistry I course. For this research, the chemistry teachers looked for the purpose of Chemistry I course based on the 7th curriculum only at the superficial views, and the teacher's wrong understanding about the tests disturbed the revelation of the spirit of Chemistry I course of the 7th national curriculum.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.1
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• pp.1-10
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• 2014

The purpose of this study is to introduce the science-play in the regular class, stimulate the student's curiosity, motivate them and take active part in their science class. To make an effective science class, we developed the science-play activity instead of experiments in the text, and applied it to the class. The experimental group has statistically meaningful results in the science process skills, expecially in subordinate elements such as observation, deduction, expectation, data analysis and assumption establishments(p<.01). However, the comparative group has no meaningful results in the science process skills. Though the average value of the science related attitude in the experimental group had only a little increase and had no statistically meaningful results, that in the comparative group has decreased during the same period. As for the experimental group, the science-play activities were repeated and their science related attitude has increased a little. Even though there were no meaningful statistic results(p>.05), the science-play activity was effective in the science related attitude. As a result of this research, it could be said that the science-play activity can improve the student's science process skills and the science related attitude, and the science-play program should be further developed and applied to make easy and effective science classes.

• BMB Reports
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• v.40 no.4
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• pp.511-516
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• 2007

A glutathione S-transferase (GST) related to the phi (F) class of enzymes only found in plants has been cloned from the Oryza sativa. The GST cDNA was cloned by PCR using oligonucleotide primers based on the OsGSTF5 (GenBank Accession No. $\underline{AF309382}$) sequences. The cDNA was composed of a 669-bp open reading frame encoding for 223 amino acids. The deduced peptide of this gene shared on overall identity of 75% with other known phi class GST sequences. On the other hands, the OsGSTF5 sequence showed only 34% identity with the sequence of the OsGSTF3 cloned by our previous study (Cho et al., 2005). This gene was expressed in Escherichia coli with the pET vector system and the gene product was purified to homogeneity by GSH-Sepharose affinity column chromatography. The expressed OsGSTF5 formed a homo-dimer composed of 28 kDa subunit and its pI value was approximately 7.8. The expressed OsGSTF5 displayed glutathione conjugation activity toward 1-chloro-2,4-dinitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy)propane and glutathione peroxidase activity toward cumene hydroperoxide. The OsGSTF5 also had high activities towards the herbicides alachlor, atrazine and metolachlor. The OsGSTF5 was highly sensitive to inhibition by S-hexylGSH, benastatin A and hematin. We propose from these results that the expressed OsGSTF5 is a phi class GST and appears to play a role in the conjugation of herbicide and GPOX activity.