• Title/Summary/Keyword: Chemistry domain

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The Analysis on the Illustrations of the Chinese Elementary Science Textbooks (중국 초등학교 과학교과서의 삽화 분석)

  • Lee, Hyeong-Cheol
    • Journal of the Korean Society of Earth Science Education
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    • v.3 no.1
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    • pp.55-64
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    • 2010
  • This study was intended to survey and analyze the illustrations of Chinese elementary science textbooks. The analysis criterion was composed of two categories, the kind of illustration and the role of illustration. The kind of illustration was divided into six subcategories categories such as photograph, picture, illustration, cartoon, diagram and recording sheet. The role of illustration was divided into four subcategories such as motive induction, guidance for learning, the supply of learning material, the presentation of learning result. The findings of this study were as follows. Chinese elementary science textbooks have about 3.55 illustrations per page. Compared with Korean ones, Chinese ones have more illustrations. From the analysis of the kinds of the illustrations on grade basis, it was found that the order of percentage of illustrations of Chinese elementary science textbooks is photograph, cartoon et al.. Photograph is prominent in entire grade. And From the analysis of the kinds of the illustrations on domain basis, the same results was founded. From the analysis of the roles of the illustrations on grade basis showed that both supply of learning material and guidance for learning are dominant in entire grade. The role of supply of learning material is a little more major than that of guidance for learning. From the analysis of the roles of the illustrations on domain basis, it was found that in domain of physics and chemistry the role of guidance for learning is major, and in domain of biology and earth science the role of supply of learning material is major.

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Coexistence of Closely Packed c(4 × 2) and Striped Phases in Self-Assembled Monolayers of Decylthiocyanates on Au(111)

  • Choi, Young-Sik;Kang, Hun-Gu;Choi, In-Chang;Lee, Nam-Suk;Cho, Jun-Hyung;Jang, Chang-Hyun;Noh, Jaeg-Eun
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.901-904
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    • 2010
  • Decylthiocyanate (DTC) self-assembled monolayers (SAMs) on Au(111) were prepared by solution and vapor phase deposition methods at $50^{\circ}C$ for 24 h. The formation and surface structure of DTC SAMs were examined using scanning tunneling microscopy (STM). STM imaging revealed that DTC SAMs formed in 1 mM ethanol solution at $50^{\circ}C$ were composed of small ordered domains with lateral dimensions of a few nanometers and disordered phases, whereas DTC SAMs formed in the vapor phase at $50^{\circ}C$ contained two ordered phases: a closely packed c($4{\times}2$) superlattice and a striped phase with an interstripe spacing of 2.6 - 2.8 nm. It was also found that the ordered domain and vacancy island formation for DTC SAMs on Au(111) differs significantly from that of decanethiol SAMs, suggesting that adsorption mechanism is different from each other. From this study, it was confirmed that DTC SAMs with a high degree of structural order can be obtained by vapor phase deposition.

An Analysis of Analogies in Chemistry Content of Middle School Science Textbooks and High School Chemistry Textbooks Developed under the 2009 Revised National Curriculum (2009 개정 교육과정에 따른 중학교 과학 교과서의 화학 영역과 고등학교 화학 교과서에 사용된 비유의 분석)

  • Kim, Kyungsun;Ahn, Inyoung;Choi, Yongnam;Noh, Taehee
    • Journal of the Korean Chemical Society
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    • v.57 no.6
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    • pp.801-812
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    • 2013
  • In this study, we analyzed the analogies in the chemistry domain of 27 middle school science textbooks and 8 high school chemistry textbooks developed under the 2009 Revised National Curriculum. A total of 284 analogies (science, 143; chemistry, 141) were identified from the textbooks, which means that 8.11 analogies (science, 5.3; chemistry, 17.6) per textbook and 0.68 analogy (science, 0.66; chemistry, 0.70) per 10 pages were used on average. Compared with previous curricula that the number of analogies gradually increased, the use of analogy was found to be somewhat decreased in the 2009 Revised National Curriculum. The number of analogies found in each textbook considerably varied depending on course, unit, and publishing company. One hundred ninety one different kinds of analogies were used, among which 38(19.9%) were used over twice. Further analyses of the types of analogies indicated that verbal and pictorial analogy, analogy with abstract target and concrete analog, and enriched analogy were frequently used. However, the term 'analogy' and the description about the limitation of the analogy were rarely mentioned. Artificial analogy, teacher-centered analogy, and analogy with low systematicity were also found to be frequently used. Educational implications of these findings are discussed.

An Efficient Method for Production of Extracellular Human Tissue Factor in Escherichia coli (인간조직인자 세포외 부분의 효과적인 제조 방법)

  • Yoo, Hwan-Goo;Park, Yang-Jin;Lee, Woo-Yiel
    • Journal of Life Science
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    • v.19 no.5
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    • pp.561-565
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    • 2009
  • Human Tissue factor is an essential enzyme activator that forms a catalytic complex with factor VII/ VIIa, and catalyzes both the extrinsic and intrinsic blood coagulation cascades. The extracellular domain of human tissue factor is responsible for association with the biological partner. The efficient procedures for preparing biologically active human tissue factor are essential for the preclinical and clinical studies with coaguligands. An expression vector in Escherichia coli has been constructed to direct the production of extracellular human tissue factor without a fusion protein or a $His_6$ at the N-terminus. The recombinant human tissue factor was expressed in large amounts as a non-native state in E. coli. The recombinant protein was simply renatured during the DEAE-sephacel chromatographic purification procedure. Our expression and purification system does not require a protease treatment or an additional chromatographic step to remove a fusion contaminant, which provides a very useful alternative to conventional expression systems for the production of human tissue factor.

Tracer Experiment for the Investigation of Urban Scale Dispersion of Air Pollutants - Simulation by CALPUFF Dispersion Model and Diffusion Feature of Tracer Gases (추적자 확산 실험에 의한 서울 도심 확산 현상 연구 - 추적기체의 확산특징과 CALPUFF 모델에 의한 모사)

  • Lee, Chong-Bum;Kim, Jea-Chul;Lee, Gang-Woong;Ro, Chul-Un;Kim, Hye-Kyeong
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.4
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    • pp.405-419
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    • 2007
  • A series of tracer experiments for the evaluation of atmospheric dispersion was performed over the urban area of Seoul using two inert, non-deposition perfluorocarbon (PMCH and m-PDCH) gases during three years campaign on 2002, 2003 and 2005. 30 sampling sites for collecting these tracers were located along two arcs of 2.5 and 5 kilometers downwind from the release point. About ten measurements which each lasted for 2 hours or 4 hours were made over the two consecutive days during each campaign. CALPUFF and MM5 meteorological model were applied to evaluate the urban dispersion in detail. Size of Modeling domain was $27\;km{\times}23\;km$ and the fine nest in the modeling domain had a grid size of 0.5 km. The results showed that CALPUFF dispersion model had a tendency to estimate tracer concentrations about $2{\sim}5$ times less than those of ambient samples under many conditions. These consistent inaccuracy in urban dispersion was attributed to inherent inaccuracy and lack of details in terrain data at urban area.

Molecular Cloning and Characterization of ${\gamma}-tocopherol$ Methyltransferase cDNA from Perilla frutescens (들깨 ${\gamma}-tocopherol$ methyltransferase cDNA 유전자의 분리 및 특성)

  • Hwang, Seon-Kap;Kim, Dong-Hern;Lee, Jai-Youl;Kim, Young-Hwan;Hwang, Young-Soo;Kim, Kyung-Hwan
    • Applied Biological Chemistry
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    • v.45 no.4
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    • pp.203-206
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    • 2002
  • ${\gamma}-Tocopherol$ methyltransferase (TMT) is an enzyme catalyzing ${\gamma}-tocopherol$ into ${\alpha}-tocopherol$ at the final step of ${\alpha}-tocopherol$ synthesis pathway. Putative TMT cDNA clone specific to Perilla frutescens immature seeds was isolated from cDNA library. The cDNA clone consisted of 1369 bp open reading frame encoding 369 amino acids with a relative Mw of 42 kDa. Results revealed the CDNA has 60% homology to Arabidopsis thaliana TMT, and possesses methyltransferase and S-adenosyl methionine-binding domains, suggesting that cDNA encodes a ${\gamma}-tocopherol$ methyltransferase To characterize the properties of the TMT gene, the cDNA sequences coding for mature TMT were expressed in E. coli and assayed to determine the enzyme activity in vitro.

Molecular Characterization of Three cDNA Clones Encoding Calmodulin Isoforms of Rice

  • Lee, Sung-Ho;Kim, Cha Young;Lim, Chae Oh;Lee, Soo In;Gal, Sang Wan;Choi, Young Ju
    • Journal of Applied Biological Chemistry
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    • v.43 no.1
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    • pp.5-11
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    • 2000
  • Three cDNA clones encoding rice calmodulin (CaM) isoforms (OsCaM-1, OsCaM-2, and OsCaM-3) were isolated from a rice cDNA library constructed from suspension-cultured rice cells treated with fungal elicitor. The coding regions of OsCaM-1 and O.sCaM-2 were 89% homologous at DNA Ievel, whereas the 5' and 3' untranslated regions were highly divergent. The polypeptides encoded by OsCaM-1 and OsCaM-2 was identical except two conservative substitution at position 8 and 75. The coding region of OsCaM-3 was consist of a typical conserved CaM domain and an additional C-terminal extension. The amino acid sequence of conserved CaM domain of OsCaM-3 shared only 86% identity with that OsCaM-1. The OsCaM-3 cDNA is belongs to a novel group of calmodulin gene due to its C-terminal extension of 38 amino acids, a large number of which are positively charged. The extension also contains a C-terminal CaaX-box prenylation site (CVlL). Genomic Southern analysis revealed at least six copies of CaM or CaM-related genes, suggesting that calmodulin may be represented by a small multigene family in the rice geneme. Expression of OsCaM gene was examined through Northern blot analysis. Transcript level of OsCaM-3 was increased by treatment with a fungal elicitor, whereas the OsCaM-1 and OsCaM-2 genes did not respond to the fungal elicitor. The expression of OsCaM-3 gene was remarkable inhibited in the rice cells treated with cyclosporine A, calcinurin inhibitor.

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Analysis of the Results of 2002 and 2003 Examination for Appointing Secondary School Science Teachers (2002 및 2003학년도 중등과학교사임용시험 결과 분석)

  • Lee, Yang-Rak
    • Journal of The Korean Association For Science Education
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    • v.24 no.3
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    • pp.532-543
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    • 2004
  • The teacher appointment examination is consisted of a written test, an interview, a demonstration of teaching practices, one's academic record etc. The primary written test(full credit of 100) consists of multiple-choice test of general pedagogy(30%) and constructed response test of science(70%). The science test consists of science education($20{\sim}30%$) and science content($70{\sim}80%$). Five science exams were implemented for appointing general science, physics, chemistry, biology and earth science teachers in 2002 and 2003. The credits alloted to science education domain decreased from $25.7{\sim}30%$ in 2002 to $24.3{\sim}25.7%$ in 2003. The percentage of correct answer was similar between science education and science content domain in 2002, but the percentage of correct answer in science education domain(70.2%) was 29.8% higher than that of science content domain in 2003. Earth science exam almost reached the target mean score of 60 but the other four exams showed the mean scores ranging from 45.0 to 52.7 in 2002 and from 40.1 to 49.6 in 2003. The percentage of high difficulty items(p<40%) was 41.2% in physics and chemistry in 2002, 50% in physics and chemistry, and 45% in biology in 2003. Seventy eight percent of the items showed fairly high discrimination index(r>.30). In addition, the reliabilities of 5 tests were from .79 to .88. In conclusion, it is recommended that the credits alloted to science education domain should be increased up to 30%, and exam difficulties should be lowered to a proper level by making science content items easier.

QSPR analysis for predicting heat of sublimation of organic compounds (유기화합물의 승화열 예측을 위한 QSPR분석)

  • Park, Yu Sun;Lee, Jong Hyuk;Park, Han Woong;Lee, Sung Kwang
    • Analytical Science and Technology
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    • v.28 no.3
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    • pp.187-195
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    • 2015
  • The heat of sublimation (HOS) is an essential parameter used to resolve environmental problems in the transfer of organic contaminants to the atmosphere and to assess the risk of toxic chemicals. The experimental measurement of the heat of sublimation is time-consuming, expensive, and complicated. In this study, quantitative structural property relationships (QSPR) were used to develop a simple and predictive model for measuring the heat of sublimation of organic compounds. The population-based forward selection method was applied to select an informative subset of descriptors of learning algorithms, such as by using multiple linear regression (MLR) and the support vector machine (SVM) method. Each individual model and consensus model was evaluated by internal validation using the bootstrap method and y-randomization. The predictions of the performance of the external test set were improved by considering their applicability to the domain. Based on the results of the MLR model, we showed that the heat of sublimation was related to dispersion, H-bond, electrostatic forces, and the dipole-dipole interaction between inter-molecules.

Thermodynamic and Structural Studies on the Human Serum Albumin in the Presence of a Polyoxometalate

  • Ajloo, D.;Behnam, H.;Saboury, A.A.;Mohamadi-Zonoz, F.;Ranjbar, B.;Moosavi-Movahedi, A.A.;Hasani, Z.;Alizadeh, K.;Gharanfoli, M.;Amani, M.
    • Bulletin of the Korean Chemical Society
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    • v.28 no.5
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    • pp.730-736
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    • 2007
  • The interaction of a polyoxometal (POM), K6SiW11Co(H2O)O39.10H2O (K6) as a Keggin, with human serum albumin (HSA) was studied by different methods and techniques. Binding studies show two sets of binding sites for interaction of POM to HSA. Binding analysis and isothermal calorimetery revealed that, the first set of binding site has lower number of bound ligand per mole of protein (ν), lower Hill constant (n), higher binding constant (K), more negative entropy (ΔS) and more electrostatic interaction in comparison to the second set of binding site. In addition, differential scanning calorimetery (DSC) and spectrophotometery data showed that, there are two energetic domains. The first domain is less stable (lower Tm and Cp) which corresponds to the tail segment of HSA and another with more stability is related to the head segment of HSA. Polyoxometal also decreases the stability of protein as Tm, secondary and tertiary structure as well as quenching of the fluorescence decrease. On other hand, perturbations in tertiary structure are more than secondary structure.