• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.97-100
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• 2004

The identification of the DNA structure as a double-stranded helix consting of two nucleotide chain molecules was a milestone in modern molecular biology. The DNA chip technology is based on reverse hybridization that follows the principle of complementary binding of double-stranded DNA. DNA chip can be described as the deposition of defined nucleic acid sequences, probes, on a solid substrate to form a regular array of elements that are available for hybridization to complementary nucleic acids, targets. DNA chips based on cDNA clons, oligonucleotides and genomic clons have been developed for gene expression studies, genetic variation analysis and genomic changes associated with disease including cancers and genetic diseases. DNA chips for gene expression profiling can be used for functional analysis in human eel Is and animal models, disease-related gene studies, assessment of gene therapy, assessment of genetically modified food, and research for drug discovery. DNA chips for genetic variation detection can be used for the detection of mutations or chromosomal abnormalities in cnacers, drug resistances in cancer cells or pathogenic microbes, histocompatibility analysis for transplantation, individual identification for forensic medicine, and detection and discrimination of pathogenic microbes. The DNA chip will be generalized as a useful tool in clinical diagnostics in near future. Lab-on-a chip and informatics will facilitate the development of a variety of DNA chips for diagnostic purpose.

• Journal of the Korean Magnetic Resonance Society
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• v.10 no.2
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• pp.175-187
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• 2006

Binding interactions between a positively charged porphyrin derivative TMAP(meso-tetra(p-trimethylanilinium-4-yl)porphyrin) and triple helical $(dT)_{12}{\cdot}(dA)_{12}{\cdot}(dT)_{12}$, as well as double helical $(dA)_{12}{\cdot}(dT)_{12}$ have been studied with NMR, UV and CD spectroscopy to obtain the detailed information about the binding mode and binding site. UV melting studies showed both DNA duplex and triple helix represented very similar UV absorption patterns upon binding TMAP, but the presence of third strand of triple helical $(dT)_{12}{\cdot}(dA)_{12}{\cdot}(dT)_{12}$, inhibited improvement in thermal stability in terms of melting temperature, $T_m$. In addition, the TMAP molecule is thought to bind to the major groove, according to CD and NMR data. But absence of the clear isosbestic point in UV absorption spectra represented that binding of TMAP to DNA duplex as well as DNA triplex did not show a single binding mode, rather complex binding modes.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.253-253
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• 2006

DNA has not been played the role as a biocatalyst in evolutionary history, although RNA and protein function as a biocatalyst. DNA double helix structure is believed to be impossible to form intricate active enzymatic sites. In addition, the chemical stability of DNA prevents the ability from self-modifying reactions. However, recent development of DNA engineering enables to create artificial enzymatic ability of DNA (deoxyribozyme) such as RNA cleavage and DNA modification. We investigated optimal conditions for enzymatic activity of DNA-Pt complex, and compared it with that of horse radish peroxidase. We report here that base sequence of DNA, pH and temperature affect the enzymatic activity of DNA-Pt complex.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.28-33
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• 2001

Screw conveyors are used extensively in industrial for conveying and elevating materials. Despite their apparent simplicity, the mechanics of the conveying action is very complex. so many engineers depend on experiential data. Capacities of screw are pumping, steady flow of polymer melts, steady volumetric throughput etc. they are affected by geometry of screw, heat flux, pressure on inside barrel, rotating velocity, friction coefficient at screw surface etc. by computation volumetric efficiency increases as rotating velocity increases and decreases as friction coefficient increases. also it decreases with short pitch length. and double flight screw is more effective than single flight screw. The temperature of polymer melts by heating pad and injection pressure play a very important role in the injection molding machine. so in this paper we analyze thermal distortion and stress of screw includes pressure and temperature distributions by finite element analysis to understand what design factors influence on volumetric throughput efficiency of the screw and thermo-mechanical characteristics of screw.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.62-66
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• 2010

Benzopyrene is known to be one of the most powerful carcinogens which can build intercalated motif between base pairs in damaged DNA. The dimension of benzopyrene itself is much bigger than any of the DNA bases and thus the question whether the lesion of some base pair by insertion of benzopyrene can happen with or without a dramatic distortion of the helical structure is a highly interesting theme. In this work we used a molecular mechanics simulation using AMBER program package to go into the conformational characteristics. The condition of the insertion process of the benzopyrene motif from minor groove of the starting structure between the base pairs in the internal area of double helix was investigated using the molecular dynamics simulation at elevated temperature.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.67-74
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• 2010

Some of the benzopyrene (BP)-DNA adduct are known to build intercalated motif between flanking base pairs in damaged DNA depending on the structural condition. The size of benzopyrene itself is definitely not comparable with any of the DNA bases and thus the question whether the lesion of some base pair by insertion of benzopyrene can happen with or without a dramatic distortion of the helical structure is a highly interesting theme. In this work we used a molecular dynamics simulation based on the theory of molecular mechanics. The specific consequences about the structural properties of the intercalated structures and benzopyrene motif in minor groove of the double helix are deduced after 5 ns simulation time.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.262-264
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• 2005

MicroRNA는 약 22 nucleotide 길이로, 세포질에서 유전자의 전사 후 조절 기능을 맡는 small RNA의 한 종류이다. MiRNA는 긴 전사체인 pri-miRNA에서 Drosha에 의해 절단 되어 핵 밖으로 나가 최종 Dicer에 의해 성숙된다. 하지만, 아직까지 이 효소들이 pri-miRNA를 잘라내는 3차 구조상의 메커니즘을 이해하지 못하고 있다. 본 연구에서는 완숙한 miRNA 이중나선이 약 2 회전을 이루게 된다는 정보를 바탕으로, Drosha가 붙는 miRNA stem구조의 dinucleotide step 파라미터를 유전 알고리즘을 이용하여 추정한다. 추정된 파라미터로부터 실제 miRNA들의 3차구조를 예측할 수 있으며, 3차 구조상의 Drosha의 절단 메커니즘을 이해하는데 도움을 줄 것이다.

• Journal of Educational Research in Mathematics
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• v.25 no.4
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• pp.717-754
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• 2015

As a design research, this study aims to identify students' collaborative problems solving patterns using the Wiki and design factors triggering MKB(mathematical knowledge building) in virtual environment. For 70 days, 14 Korean secondary gifted students, who enrolled in calculus II courses in one of gifted institutions in Korea, solved 10 math problems together using the Wiki. In this study, I considered five design factors; motivation, practice of LaTeX, norms of participation, epistemic agency, and two types of educational settings. The primary pattern emergent in students' collaborative problem solving process is identified as 'solutions and refutations' along the double helix consisting of the constructive line and the critical line, which is very similar to the pattern of 'Conjectures and Refutations'(Lakatos, 1976). Despite that most participants had difficulty in using LaTeX for mathematical expressions, this study shows that Wikis are valuable tools for providing Korean secondary students opportunities to learn social virtue such as humility and courage (Lampert, 1990), which is considered to be have been neglected in Korean educational environment but is emphasized as precious for doing mathematics in the field of mathematics education.

• Journal of Distribution Research
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• v.15 no.5
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• pp.127-153
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• 2010

This study explores the locomotives of the growth in the Korean online shopping industry upon the theoretical basis based on the last 10 years' rapid changing environment. This attempt reveals the counter-arguments against preemtive effects based on the observation of reintermediation process in the online industry. We reviewed the NEBIC model proposed by Wheeler(2002) and propose the growth model, double helix framework based on the dynamic capability view. Furthermore the relevance of the proposed framework was validated with the review of last 10 years' sales and market share data in the online shopping industry. Meanwhile we found the limits of online market growth with the open market domination. So future of the online shopping retailers is depending on the development of the channel functions and merchandising on the basis of self-capability. Based on the tentative conclusion, we also suggest implications for the policy makers. Firstly policy facilitating the specialization of the power sellers incubased in the open market is necessary for the sustainable online market growth. And the establishment of the control tower is suggested to coordinate the consistency of the policies and regulations. And the device of the incentive is also proposed to strengthen the open markets' function to facilitate the small and medium online merchants.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.149-155
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• 1987

Growth and development of a higher plant, or any living organism for that matter, could be defined as an orderly expression of the genome in time and space in close interaction with the environment. During differentiation and development of a tissue or organ a group of genes must be selectively turned on or turned off mainly by trans-acting regulators. In this general concept of regulation of regulation of gene expression, a DNA molecule is recognized at a specific nucleotide sequence by DNA-binding factors. Molecular biology of the regulatory factors such as hormones, and their receptors, target DNA sequences and DNA-binding proteins are well advanced. What is not clearly understood is the molecular basis of the interactions between DNA and binding factors, expecially of the usages of the dyad symmetry of the target DNA sequences and the dimeric nature of the DNA-binding proteins. A unique 3-dimensional structure of DNA has been proposed that may play an important role in the orderly expression of the gene. A foldback intercoil (FBI) DNA configuration which was originally found by electron microscopy among mtDNA molecules from pearl millet has some unique features. The FBI configuration of DNA is believed to be formed when a flexible double helix folds back and interwines in the widened major grooves resulting in a four stranded, intercoil DNA whose thickness is the same as that of double stranded DNA. More recently, the FBI structure of DNA has been also induced in vitro by a novel enzyme which was purified from pearl millet mitochondria. It has been proposed that the FBI DNA could be utillized in intramolecular recombination which leads to inversion or deletion, and in intermolecular recombination which can lead to either site-specific recombination, genetic recombination via single strand invasion, or cross strand recombination. The structure and function of DNA in 3-dimensional aspect is emphasized for better understanding orderly expression of genes during growth and development.