• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.376-388
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• 2023

After a longitudinal analysis of the data on the college entrance examination of students enrolled in the Department of Chemistry Education at Gyeongnam from 2014 to 2021, the effect on the academic achievement of general chemistry according to the type of college entrance examination was studied. And the impact on the academic achievement of general chemistry according to the type of admission screening in face-to-face and non-face-to-face teaching-learning was also studied. As a result of analyzing the academic achievement of general chemistry by admission process, students admitted through occasional screening showed relatively high grades of A and B at 88.7%, and the ratio of grades of 1~3 of chemistry I in high school was high. On the other hand, in the case of students admitted through regular admission, the ratio of grades of A and B in general chemistry was very high at 94.3%, and the ratio of grades of 3~4 in chemistry I of the College Scholastic Ability Test was high. As a result of analyzing the academic achievement of general chemistry by class type and admission process, it was found that the grades of chemistry I by face-to-face classes had an effect on the academic achievement of general chemistry in non-face-to-face classes. In both admissions, the academic achievement of general chemistry by face-to-face classes was relatively higher than that of non-face-to-face-to-face classes.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.611-620
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• 2010

The purpose of this study was to explore the structure and content of chemistry teacher's explanations from the perspective of 'persuasion'. Especially, this study was to explore how the argument structure and the conceptual change constructs in chemistry teachers' explanations were established and interacted. Data were collected from chemistryI classes considering the gas unit which includes kinetic theory of gas, Graham's law, Boyle's law, and Charles' law. The classes were vediotaped and transcribed. The transcriptions were analyzed with Toulmin's argument frame and the two constructs of conceptual change model; the conceptual ecology and the status of a conception to interpret the persuasive structure and content of the teacher's explanations. As the results of this study, four explanatory discourses which show various persuasive explanations in chemistry classes. Based on this results, discussion and implications for effective teachers' explanations in chemistry classes were presented.

• Journal of the Korean Chemical Society
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• v.59 no.1
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• pp.69-77
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• 2015

The purpose of this study was to examine changes in student writings of claim and evidence after group and class discussions; changes in students' critical thinking; and students' perceptions on an argument-based claim and evidence writing approach. Seventy two grade 11 students from two classes of a high school located in Seoul participated in ten chemistry activities using the argument-based claim and evidence writing approach. Claim scores for 9 topics and evidence scores for 10 topics significantly improved after group discussion. There were also statistically significant differences in claim scores for 7 topics and evidence scores for 10 topics after class discussion. Participant students responded to an open-ended survey that group discussion helped them to figure out the problem context and class discussion guided them to provide with more sufficient evidence. There were also statistically significant increases in sub-scores of the Cornell Critical Thinking Test after the intervention.

• Journal of the Korean Chemical Society
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• v.64 no.3
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• pp.159-174
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• 2020

The purpose of this study is to examine 'Design Thinking' based Chemistry Class program as an education strategy for core competence of creative convergence talent. The program stages were modified and supplemented into eight stages, including 'Knowledge Understand', 'Empathy', 'Sharing perspective', 'Ideate', '1st Prototype', '1st Test', '2nd Prototype', and '2nd Test', so that the 'Design Thinking Process in Science Education' can be applied to the chemistry class. Considering the linkage between the 2015 and 2009 revised national curriculum, the achievement criteria were selected, and the lesson plans and student activity sheet were developed according to the themes to be met. Four thematic educational programs were developed and applied to Chemistry I for the second grade of high school students from March to August. The results were verified through qualitative data analysis of the class scene and pre- and post-test based on inventories of 'Empathy' 'STEAM educational competence', 'Problem solving process'. As a result of applying the developed program, 'empathy' showed a significant improvement in empathy with others and empathy with the problem situation. In 'STEAM educational competence', there was a significant enhancement in science and design competence. In the 'problem finding process', the problem definition, problem solution design, and problem-solving review were significantly improved in the 'problem-solving process'. The results of this study provided implications for the applicability of design thinking - based chemistry classes and its educational effect.

• 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.

• Journal of the Korean Chemical Society
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• v.53 no.1
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• pp.34-41
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• 2009

A new series of hydrazone derivatives were synthesized from 4-(2-chloroethyl)semicarbazide and their antiproliferative activity against human brain (U251) and liver (Hepg2) carcinoma cell lines were evaluated. The hydrazone compounds are benzaldehyde (2a-2g), acetophenone (3a-3f), and 3-formylindole derivatives (4a-4d). Among the acetophenone derivatives, 3e (p-methoxy substituted) and 3f (p-nitro substituted) showed the highest cytotoxic activity against Hepg2 cell line (I$C_{50}$ = 6 and 8 $\mu$g/ml, respectively). Among the 3-formylindole derivatives, 4a (hydrazone of 3-formylindole itself) showed a pronounced cytotoxic activity against both U251 (I$C_{50}$ = 21 $\mu$g/ml) and Hepg2 (I$C_{50}$ = 7 $\mu$g/ml).

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1361-1367
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• 2010

A series of O,O-dialkyl-1-phenoxyacetoxy-1-methylphosphonate analogues (1~22) as a new class of potent inhibitors of pyruvate dehydrogenase were synthesized and 3D-QSARs (three dimensional qantitative structure-activity relationships) models on the pre-emergency herbicidal activity against the seed of cucumber (Cucumus Sativa L.) were derived and discussed quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indeces analysis (CoMSIA) methods. The statistical values of CoMSIA models were better predictability and fitness than those of CoMFA models. The inhibitory activities according to the optimized CoMSIA model I were dependent on the electrostatic field (41.4%), the H-bond acceptor field (26.0%), the hydrophobic field (20.8%) and the steric field (11.7%). And also, it was found that the optimized CoMSIA model I with the sensitivity to the perturbation ($d_q{^{2'}}/dr^2{_{yy'}}$ = 0.830) and the prediction ($q^2$ = 0.503) produced by a progressive scrambling analyses were not dependent on chance correlation. From the results of graphical analyses on the contour maps with the optimized CoMSIA model I, it is expected that the structural distinctions and descriptors that subscribe to herbicidal activities will be able to apply new an herbicide design.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1295-1299
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• 2010

Recently, recombinant Streptomyces venezuelae has been established as a heterologous host for microbial production of flavanones and stilbenes, a class of plant-specific polyketides. In the present work, we expanded the applicability of the S. venezuelae system to the production of more diverse plant polyketides including flavones and flavonols. A plasmid with the synthetic codon-optimized flavone synthase I gene from Petroselium crispum was introduced to S. venezuelae DHS2001 bearing a deletion of the native pikromycin polyketide synthase gene, and the resulting strain generated flavones from exogenously fed flavanones. In addition, a recombinant S. venezuelae mutant expressing a codon-optimized flavanone $3{\beta}$-hydroxylase gene from Citrus siensis and a flavonol synthase gene from Citrus unshius also successfully produced flavonols.

• Bulletin of the Korean Mathematical Society
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• v.51 no.5
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• pp.1241-1257
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• 2014

We consider a class of hypoelliptic operators of the following type $$L=\sum_{i,j=1}^{p_0}a_{ij}{\partial}^2_{x_ix_j}+\sum_{i,j=1}^{N}b_{ij}x_i{\partial}_{x_j}-{\partial}_t$$, where ($a_{ij}$), ($b_{ij}$) are constant matrices and ($a_{ij}$) is symmetric positive definite on $\mathbb{R}^{p_0}$ ($p_0{\leqslant}N$). By establishing global Morrey estimates of singular integral on the homogenous space and the relation between Morrey space and weak Morrey space, we obtain the global weak Morrey estimates of the operator L on the whole space $\mathbb{R}^{N+1}$.

• Applied Biological Chemistry
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• v.51 no.2
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• pp.119-123
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• 2008

3D-QSARs (3 dimensional quantitative structrue-activity relationships) on the inhibition activities of 3-substituted-5,5'-diphenylimidazolidine-2,4-dione derivatives (1-22) against FAAH (fatty acid amide hydrolase) were studied quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indice analysis) methods. The statistical results of the CoMFA 1A and CoMSIA 2F model are better predictability and fitness. And also, the designed X=I, Y=$N_{2}^{+}$-substituent (P1: $Pred.pI_{50}$=6.55), according to the contour maps with information of the two models, showed the most inhibition activity against FAAH.