• 제목/요약/키워드: Chemistry domain

검색결과 249건 처리시간 0.024초

중학교 과학 영재 학생의 과학 관련 태도에 관한 연구 (Study on Attitude of Science Gifted and Talented Middle School Students toward Science)

  • 소금현;심규철;이현욱;장남기
    • 한국과학교육학회지
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    • 제20권1호
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    • pp.166-173
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    • 2000
  • 본 연구는 중학교 과학영재 학생들의 과학관련 태도에 대하여 조사하였다. 조사 도구는 TOSRA를 우리나라 중학교 학생에 맞게 수정 보완하여 사용하였으며, 1999년도 서울대학교 과학영재 센터의 제 2기 입학생 131명을 연구 대상으로 하여 조사하였다. 서울대학교 과학영재교육센터의 입학생은 수학, 물리, 화학, 생물 및 지구과학 등 5개 분과로 구성되어 있다. 중학교 과학영재들의 과학관련 태도 수준은 전체적으로 남녀 학생간에 유의미한 차이가 없었으나, '과학에 대한 직업적 관심' 영역에서만 과학영재 남학생들이 여학생들에 비해 높은 수준을 갖는 것으로 조사되었다. 과학관련 태도 각 영역에 대한 비교에서는 과학 영재 학생들이 '과학에 대한 취미적 관심' 영역에서 가장 높은 태도 점수를 나타낸 반면에, '과학자의 평범성' 영역에서는 가장 낮은 수준을 나타내었다. 과학 영재들의 분과에 따른 비교에서는 화학 분과를 제외하고는 다른 분과간에는 유의미한 차이가 없었으나, 특히 화학 분과 영재들은 수학 분과에 비해서'과학적 태도의 수용' 영역에서 매우 높게 나타났다. 과학 영재들의 과학적 특성을 파악하고 유지시켜 줄 수 있는 연구와 과학 영재 학생을 위한 과학 영재 자신의 자아실현을 위함과 국가의 과학적 발전에 기여할 수 있는 특수한 교육 프로그램의 개발은 물론 사회적 및 국가적 지원이 있어야 할 것이다.

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서로 다른 질량을 가진 분자들로 이루어진 대기의 조성에 대한 과학교사들의 인식 변화 (Change of Science Teachers' Perceptions About the Atmosphere Composition of Molecules with Different Masses)

  • 유승균;백성혜
    • 대한화학회지
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    • 제62권4호
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    • pp.288-298
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    • 2018
  • 이 연구에서는 과학교사 11명을 대상으로 서로 다른 질량을 가진 분자들로 이루어진 대기의 균질권에 대한 사고를 알아보기 위하여 사전 사후 검사지를 개발하고 조사하였다. 사전 검사 결과, 교사들은 크게 2가지 유형의 사고로 분류되었으며, 대기를 균일 용액처럼 생각하여 조성비가 균일하다는 사고와 입자의 질량이 다름을 고려하여 대기의 조성비가 비균질하다는 사고가 나타났다. 각각의 사고는 다시 중력의 크기를 크게 고려한 경우와 작게 고려한 경우, 그 중간 정도로 고려한 경우 등 3가지 유형으로 재분류 되어서 총 6가지 유형의 사고를 찾아볼 수 있었다. 이러한 다양한 사전 개념을 제시하고 교사들에게 학문간 교차개념의 중요성을 소개한 후에 화학에서의 원자량과 온도에 따른 분자 운동, 공기라는 용액의 균질성, 물리에서 다루는 질량과 중력, 그리고 거리의 관계, 지구과학에서 다루는 대기의 분포 및 대류 현상 등의 개념을 연계하여 사고하도록 제안하였다. 교사들 간의 토론 후에 사후 개념을 조사한 결과 사전 개념에서 벗어나 중력, 질량, 온도, 고도 등을 고려하여 대기의 조성에 대한 통합적 시각을 가지는 사고로 변화하였다. 이러한 변화를 통해 다양한 학문에서 다루는 교차개념의 중요성에 대해 확인할 수 있었으며, 통합과학에서 앞으로 이러한 유형의 사고를 교사들이 학생들에게 제공함으로써 일관된 세계관을 형성하고 지적 도구로 탐구적 사고를 실행할 수 있도록 도울 필요가 있다고 이 연구에서는 제안하였다.

Prostaglandin E Synthase, a Terminal Enzyme for Prostaglandin E2 Biosynthesis

  • Kudo, Ichiro;Murakami, Makoto
    • BMB Reports
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    • 제38권6호
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    • pp.633-638
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    • 2005
  • Biosynthesis of prostanoids is regulated by three sequential enzymatic steps, namely phospholipase $A_2$ enzymes, cyclooxygenase (COX) enzymes, and various lineage-specific terminal prostanoid synthases. Prostaglandin E synthase (PGES), which isomerizes COX-derived $PGH_2$ specifically to $PGE_2$, occurs in multiple forms with distinct enzymatic properties, expressions, localizations and functions. Two of them are membrane-bound enzymes and have been designated as mPGES-1 and mPGES-2. mPGES-1 is a perinuclear protein that is markedly induced by proinflammatory stimuli, is down-regulated by anti inflammatory glucocorticoids, and is functionally coupled with COX-2 in marked preference to COX-1. Recent gene targeting studies of mPGES-1 have revealed that this enzyme represents a novel target for anti-inflammatory and anti-cancer drugs. mPGES-2 is synthesized as a Golgi membrane-associated protein, and the proteolytic removal of the N-terminal hydrophobic domain leads to the formation of a mature cytosolic enzyme. This enzyme is rather constitutively expressed in various cells and tissues and is functionally coupled with both COX-1 and COX-2. Cytosolic PGES (cPGES) is constitutively expressed in a wide variety of cells and is functionally linked to COX-1 to promote immediate $PGE_2$ production. This review highlights the latest understanding of the expression, regulation and functions of these three PGES enzymes.

Classification and Expression Profiling of Putative R2R3 MYB Genes in Rice

  • Kim, Bong-Gyu;Ko, Jae-Hyung;Min, Shin-Young;Ahn, Joong-Hoon
    • Journal of Applied Biological Chemistry
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    • 제48권3호
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    • pp.127-132
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    • 2005
  • MYB genes, comprising group of related genes found in animal, plant, and fungal genomes, encode common DNA-binding domains composed of one to four repeat motifs. MYB genes containing two repeats (R2R3) constitute largest MYB gene family in plants. R2R3 MYB genes play important roles in regulation of secondary metabolism, control of cell shape, disease resistance, and hormone response. Eight-four R2R3 MYB genes were retrieved from rice genome for functional characterization of MYB genes. Analysis of MYB domains revealed each MYB domain contains three ${\alpha}$-helices with regularly spaced tryptophan residues. R2R3 MYB genes were divided into four subfamilies based on phylogenic analysis result. Real-time PCR analysis of 34 MYB genes revealed 12 MYB genes were highly expressed in seeds than in leaves, whereas 4 genes were highly expressed in leaves.

Heptaphylline Induces Apoptosis in Human Colon Adenocarcinoma Cells through Bid and Akt/NF-κB (p65) Pathways

  • Boonyarat, Chantana;Yenjai, Chavi;Vajragupta, Opa;Waiwut, Pornthip
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권23호
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    • pp.10483-10487
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    • 2015
  • Heptaphylline derivatives are carbazoles in Clausena harmandiana, a medicinal plant that is utilized for headache, stomach ache, and other treatments of illness. The present study examined the effects of heptaphylline and 7-methoxyheptaphylline on apoptosis of human colon adenocarcinoma cells (HT-29 cell line). Quantification of cell viability was performed using cell proliferation assay (MTT assay) and of protein expression through immunoblotting. The results showed that only heptaphylline, but not 7-methoxyheptaphylline, significantly significantly activated cleaved of caspase-3 and poly (ADP-ribose) polymerase (PARP-1) which resulted in HT-29 cell death. We found that heptaphylline activated BH3 interacting-domain death agonist (Bid) and Bak, proapoptotic proteins. In contrast, it suppressed X-linked inhibitor-of-apoptosis protein (XIAP), Bcl-xL and survivin, inhibitors of apoptosis. In addition, heptaphylline inhibited activation of NF-${\kappa}B$/p65 (rel), a regulator of apoptotic regulating proteins by suppressing the activation of Akt and $IKK{\alpha}$, upstream regulators of p65. The findings suggested that heptaphylline induces apoptosis in human colon adenocarcinoma cells.

Scrap PVB/PMMA 블렌드에 미치는 MBS의 상용화효과(相溶化效果) (The Effect of MBS on the Compatibility of Scrap PVB/PMMA Blends)

  • 최형기;이용무;윤주호;최세영
    • Elastomers and Composites
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    • 제31권1호
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    • pp.23-32
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    • 1996
  • PVB was blended with PMMA in order to recycle scraped PVB material which recovered in the safety glass manufactories. The purpose of this research on PVB/PMMA blend was applied with excellent tackiness and transparency of PVB as a material of high strength to make the maximum use. Also, the blending of PVB with PMMA was aimed at the increase of impact strength of PMMA because the elastic property of PVB might decrease the brittleness of PMMA due to the lack of inner impact resistance. Izod impact resistance was propotional to increase the content of PVB, which was predominantly increased in the addition of 10phr above MBS. High rate impact resistance showed a tendency to Increase but it showed a tendency to decrease maximum load and energy if the contents of PVB increased. On the other hand total energy and ductile index showed a tendency to increase excellent impact resistance in the addition of MBS contents. As a result of observed surface of PVB/PMMA blends, the size of PVB domain increased distribution homogenuously, in the addited MBS contents increased it showed distribution homogeneously and partially a wetability.

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DNA Polymorphism Analysis of the HLA-DRB1 Gene Using Polymerase Chain Reaction-Sequence Specific Primer (PCR-SSP) among Korean Subjects

  • Lee, Kyung-Ok;Park, Taek-Kyu;Park, Young-Suk;Oh, Moon-Ju;Kim, Yoon-Jung
    • BMB Reports
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    • 제29권1호
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    • pp.45-51
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    • 1996
  • Most expressed HLA loci exhibit a remarkable degree of allelic polymorphism, which derives from sequence differences predominantly localized to discrete hypervariable regions of the amino-terminal domain of the molecule. In this study, the HLA-DRB1 genotypes were determined in eighteen control cell lines and 112 unrelated Koreans using the PCR-SSP (Polymerase Chain Reaction-Sequence Specific Primer) technique. 29 specific primer pairs in assigning the DRB1 gene were used. The results of control cells correlated well with the data which was previously reported. The heterozygosity and homozygosity of the DRB1 gene were 0.786 and 0.214, respectively. In a total of 41 different DRB1 alleles and 83 genotypes, the most frequent allele and genotype were DRB1*04 and DRB1*0901/1501, respectively. This study shows that the PCR-SSP technique is relatively simple, fast and a practical tool for the determination of the HLA-DRBI genotypes. Moreover, these results-allele and genotype frequency and heterozygosity of the HLA DRB1 gene-could be useful for database study before being applied to individual identification and transplantation immunity.

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NMR Study of the pH Effect on the DNA Binding Affinity of Human RPA

  • Lee, Min-Woo;Choi, Ju-Hyeok;Choi, Jae-Gyu;Lee, Ae-Ree;Lee, Joon-Hwa
    • 한국자기공명학회논문지
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    • 제20권3호
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    • pp.71-75
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    • 2016
  • The replication protein A (RPA) plays a crucial role in DNA replication, recombination, and repair. RPA consists of 70, 32 and 14 kDa subunits and has high single-stranded DNA (ssDNA) binding affinity. The largest subunit, RPA70, mainly contributes to bind to ssDNA as well as interact with many cellular and viral proteins. In this study, we performed nuclear magnetic resonance experiments on the complex of the DNA binding domain A of human RPA70 (RPA70A) with ssDNA, d(CCCCC), at various pH, to understand the effect of pH on the ssDNA binding of RPA70A. The chemical shift perturbations of binding residues were most significant at pH 6.5 and they reduced with pH increment. This study provides valuable insights into the molecular mechanism of the ssDNA binding of human RPA.

Effects of Polyelectrolytes on the Charge Transfer Complexing between Indole derivatives and Methylviologen: Hydrophobic and Electrostatic Interactions

  • Park, Joon-Woo;Hwang, Book-Kee
    • Bulletin of the Korean Chemical Society
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    • 제6권3호
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    • pp.145-148
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    • 1985
  • The effect of anionic polyelectrolytes, poly(styrenesulfonate) (PSS) and poly(vinylsulfonate) (PVS), on the charge transfer complexing between indole derivatives and methyl viologen($MV^{++}$) cation was investigated. The results were compared with effect of NaCl and an anionic surfactant, sodium dodecylsulfate (SDS). Both PSS and PVS enhanced the complex formation of neutral species (indole and indole acetate at low pH), zwitter ionic tryptophan, and positively charged tryptamine and tryptophan at low pH with $MV^{++}$. This result was attributed to the contribution of hydrophobic interaction, in addition to electrostatic interaction. The enhancing effect of PSS was much higher than that of PVS reflecting the higher hydrophobicity of PSS. The interaction between indole acetate anion and $MV^{++}$ was greatly reduced by addition of PVS and PSS. The higher charge density of PVS was appeared as greater reducing effect indicating the importance of electrostatic force in this case. In all cases, the effect of polyelectrolytes showed maxima, and further addition of PVS and PSS decreased the effect. This behavior was explained in terms of distribution of indole derivatives and $MV^{++}$ in domain of polyanions. The complex formation constants and molar absorptivities of complexes were determined, and the values were compared with those in water and SDS solutions.

이종분야 융합을 통한 연구영역 도출 프로세스 수립 - ICT-화학안전을 중심으로 (The Process for Deriving Research Area by Converging Heterogeneous field - Focused on ICT-Chemistry Safety)

  • 심위;서성호;정현상;최재경;강종석
    • 한국산업융합학회 논문집
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    • 제22권2호
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    • pp.201-208
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    • 2019
  • Since the introduction of the open innovation at the beginning of the 2000s, various studies have been carried out on the convergence of technologies, such as the development of new technologies and the development of the business domain. while exploring the technologies necessary for the convergence of appropriate technologies in this research, we propose a discovery process of challengeable research areas by means of the integration of heterogeneous fields which are based on the strategic formulation of ICT and chemical safety industry. In this paper, we consequently propose the 103 detailed convergent technologies based on ICT, especially including artificial intelligent technology and smart big-data platform architecture, were derived from the research areas of the chemical safety field, We expect that research related to the safety field will be frustrated in the future.