• Journal of the Korean Chemical Society
• /
• v.45 no.5
• /
• pp.470-480
• /
• 2001

The purpose of this study was to investigate the effects of science inquiry experiments emphasizing social interaction on the development of process skills of the students. The social interactions by cognitive level of the students were also analyzed. For this study, 197 8th grade students were sampled. They were divided into an experimental group and a control group. During four-month period, the experimental group received science inquiry experiments treatment emphasizing social interactions while the control group received traditional treatment. Not only science inquiry ability pretest-posttest, but also multiple data collection method such as a questionnaire, class observation, and audio/video recording were used in collecting the data. According to the results of this study, it was found that the mean score of the experimental group was significantly higher than that of the control group at 0.05 level. It was also found that the students of high cognitive level led the peers and participated in the class discussion actively with the teacher while the students of low cognitive level followed the students of high cognitive level and showed inactive interaction with the teacher. Analysis of the students' perceptions on inquiry experiments showed that students participated in discussion actively in the class as these experiments gave an opportunity for them to discuss and were able to solve the problems with peers' help through discussion.

• Journal of Applied Biological Chemistry
• /
• v.59 no.2
• /
• pp.159-164
• /
• 2016

Plant growth regulator is an essential pesticide to date while the available active ingredient is not well understood unlike fungicide, insecticide and herbicide. This study was aimed to evaluate a new chemical class of plant growth regulator, and the total of 92 benzene derivatives were screened for their germination and early stage of the root growth regulation on Brassica campestris. Thirty benzaldehydes, nine acids, one amide, and one ester showed potent root growth inhibitory activity (>70 % inhibition) while only salicylaldehyde showed potent germination inhibition ($IC_{50}=81.2mg/L$) suggesting that benzaldehyde was a key module candidate for the growth inhibition. Benzaldehydes were further evaluated for root growth inhibition. 2,3-Dihydroxybenzaldehyde and salicylaldehyde showed $IC_{50}$ values of 8.0 and 83.9 mg/L, respectively. On the other hand, salicylaldehyde, and 2,4,5-trihydroxybenzaldehyde were found to have root growth promotion effects less than 10 mg/L. This result suggests that the benzaldehyde is a new class candidate for plant growth regulator.

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

• Bulletin of the Korean Chemical Society
• /
• v.31 no.5
• /
• pp.1361-1367
• /
• 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 the Korean Chemical Society
• /
• v.50 no.5
• /
• pp.385-393
• /
• 2006

In this study, we analyzed the effects of science inquiry learning that applies open-ended hypothesis-testing learning model in a high school chemistry class of grade 11 in respect of science process skills, science-related attitude, and appreciation towards science class by cognitive level. Open-ended science inquiry learning activities on Metals and their applications unit in Chemistry I were developed and applied to the treatment groups while the conventional science activities were applied to the control groups. Four classes of 92 students in a high school located in Seoul were assigned into the treatment and control groups, respectively. According to the results in the test of science process skills, the students treated with the alternative experiments emphasizing open-ended hypothesis-testing obtained higher scores in experimental design, data conversion and description, and hypothesis test than those with conventional experiments but not in problem cognition and definition and hypothesis fixing'. There was negative effect on science-related attitude due to increased roles and tasks in the open-ended science inquiry learning activities.

• Journal of the Korean Chemical Society
• /
• v.48 no.2
• /
• pp.182-188
• /
• 2004

In this study, the effects of a four-stage problem-solving strategy emphasizing planning and checking stages were investigated. Two high school classes (N=55) were randomly assigned to either treatment or control group, and taught about two topics, 'gas' and 'solution' for 8 class hours. Teacher used the four-stage problem-solving strategy emphasizing planning and checking stages in the treatment group, and used traditional lecture in the control group. Two-way ANCOVA results revealed that the test scores of the treatment group were significantly higher than those of the control group in the problem-solving ability, especially in the subcategories of 'conceptual knowledge' and 'mathematical execution'. There was significant interaction between the instruction and the level of prior achievement in the 'satisfaction' of the learning motivation. The lower level students in the control group were more satisfied with chemistry class than those in the treatment group. There was no significant difference between the two groups in the scores of the awareness of metacognition. Educational implications are discussed.

• Journal of the Korean Chemical Society
• /
• v.57 no.4
• /
• pp.499-506
• /
• 2013

In this study, clicker, also known as classroom response system, was applied to the chemistry method course at the university in Gyeongbuk, and preservice chemistry teachers' perceptions of clicker were surveyed. Before starting lecture, operation and class application of clickers were introduced to preservice teachers, and then 4-5 questions were presented to them in most classes during the term. After preservice teachers were asked to answer the questions, lecturer gave feedback based on the class answer distribution. Questions presented to preservice teachers were recall and/or understanding questions on learning contents, opinion questions, and questions about muddiest point. At the end of semester, preservice teachers were asked to rate their perception of clikers in terms of likert scale and essay type. They had positive perceptions of clicker use in aspects of cognitive effects, affective effects and media characteristics. They preferred conceptual understanding questions and monitoring questions among 8 clicker question types. Some cases using clickers in lecture and educational implications were also included.

• Journal of Korean Elementary Science Education
• /
• v.29 no.3
• /
• pp.341-349
• /
• 2010

In this study, the effects of concept mapping with feedbacks providing explanatory comments on students' achievement, science learning anxiety, and science learning motivation were investigated in the undergraduate general chemistry course. The aptitude-treatment interactions between students' level of mastery goal orientation and the concept mapping with explanation feedback treatment were also examined. Sixty-seven freshmen from an university of education were assigned to a control group and a treatment group. The tests of mastery goal orientation, science anxiety, and science learning motivation were administered as pretests. For the treatment group, feedback providing students with explanatory comments through whole class discussion was presented after each concept mapping. Whereas the control group students were presented with opportunities solving excercise problems followed by explanation feedback. The intervention was lasted for 10 weeks (30 class periods). After the instructions, a researcher-made achievement test, the science learning anxiety test, and the science learning motivation test were administered. The results indicated that no statistically significant difference was found in students' achievement. In the science learning anxiety, however, the scores of the treatment group was significantly lower than those of the control group. The scores of the treatment group also tended to be higher, though not significant, than those of the control group in the science learning motivation. However, no significant aptitude-treatment interactions were found in all dependent variables.

• Molecules and Cells
• /
• v.28 no.5
• /
• pp.447-453
• /
• 2009

The quorum sensing (QS) inhibitors that antagonize TraR, a receptor protein for N-3-oxo-octanoyl-L-homoserine lactones (3-oxo-C8-HSL), a QS signal of Agrobacterium tumefaciens were developed. The structural analogues of 3-oxo-C8-HSL were designed by in silico molecular modeling using SYBYL packages, and synthesized by the solid phase organic synthesis (SPOS) method, where the carboxamide bond of 3-oxo-C8-HSL was replaced with a nicotinamide or a sulfonamide bond to make derivatives of N-nicotinyl-L-homoserine lactones or N-sulfonyl-L-homoserine lactones. The in vivo inhibitory activities of these compounds against QS signaling were assayed using reporter systems and compared with the estimated binding energies from the modeling study. This comparison showed fairly good correlation, suggesting that the in silico interpretation of ligand-receptor structures can be a valuable tool for the pre-design of better competitive inhibitors. In addition, these inhibitors also showed anti-biofilm activities against Pseudomonas aeruginosa.

• Fire Science and Engineering
• /
• v.23 no.2
• /
• pp.67-77
• /
• 2009

The purpose of this study is to deal with fire fighting safety education primarily among the fields of child safety education. So, first of all, this study considered the theoretical background of fire fighting safety education. And this study analyzed the present state and cases of safety accidents in elementary schools. And by focusing on the fire fighting science class for elementary schools which Gyeonggi-do Goyang fire station is executing now, this study analyzed the educational outline, present state, educational goal, and content of fire fighting science class, and conducted the satisfaction survey through questionnaire over the elementary school students participating in fire fighting science class and the fire fighting officers in charge of fire fighting science class. On basis of this research, by developing the new field of fire fighting education and publicity into the program which can diffuse the fire fighting-related chemical experiment based on the science of chemistry and physics in the future and so provide the pleasure and surprise of experiencing directly not only natural fire fighting education and publicity but also learning and the common sense of fire fighting, this study tried to present the alternatives about the measures for activating the fire fighting safety education in elementary schools.