• Title/Summary/Keyword: Molecular rearrangement

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Layer-by-layer Composition Modulation by Ion-induced Atomic Rearrangement in Metallic Alloys

  • Kim, Byeong-Hyeon;Kim, Sang-Pil;Lee, Gwang-Ryeol;Jeong, Yong-Jae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.359-359
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    • 2010
  • Self-organized nanostructures of dots, holes or ripples produced by energetic ion bombardment have been reported in a wide variety of substrates. Ion bombardment on an alloy or compound also draws much attention because it can induce a surface composition modulation with a topographical surface structure evolution. V. B. Shenoy et al. further suggested that, in the case of alloy surfaces, the differences in the sputtering yields and surface diffusivities of the alloy components will lead to a lateral surface composition modulation [1]. In the present work, the classical molecular dynamics simulation of Ar bombardment on metallic alloys at room temperature revealed that this bombardment induces a surface composition modulation in layer-by-layer mode. In both the $Co_{0.5}Cu_{0.5}$ alloy and the CoAl B2 phase, the element of higher-sputtering yield is accumulated on the top surface layer, whereas it is depleted in lower layers. A kinetic model considering both the rearrangement and the sputtering of the substrate atoms agrees with the puzzling simulation results, which revealed that the rearrangement of the substrate atoms plays a significant role in the observed composition modulation.

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Possible Involvement of Rearranged Proto-oncogene in T Cell Malignancy

  • Lee, Kwang-Ho;Lee, Seung-Gak;Park, Tae-Kyu
    • BMB Reports
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    • v.28 no.5
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    • pp.414-419
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    • 1995
  • The retroviruses carrying ${\nu}-myc$ and ${\nu}-raf$ oncogenes were infected into fetal thymic organ culture (FTOC) to study the molecular mechanisms involved in T cell development. T cell lymphomas in the different stages of T cell development were obtained from this culture system. Interestingly, a few cell lines obtained from this system have a lack of transfected oncogenes, however these cells have the characteristics of transformed cells. In spite of the discrete phenotype of these transformed cell lines, the same pattern of recombination of endogenous c-raf genes was detected from Southern blot analysis. We suggest in this regard that the translocation event of thymocytes, or abnormal promoter activity, can cause lymphomagenesis by way of c-raf.

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Biopsy and Mutation Detection Strategies in Non-Small Cell Lung Cancer

  • Jung, Chi Young
    • Tuberculosis and Respiratory Diseases
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    • v.75 no.5
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    • pp.181-187
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    • 2013
  • The emergence of new therapeutic agents for non-small cell lung cancer (NSCLC) implies that histologic subtyping and molecular predictive testing are now essential for therapeutic decisions. Histologic subtype predicts the efficacy and toxicity of some treatment agents, as do genetic alterations, which can be important predictive factors in treatment selection. Molecular markers, such as epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement, are the best predictors of response to specific tyrosine kinase inhibitor treatment agents. As the majority of patients with NSCLC present with unresectable disease, it is therefore crucial to optimize the use of tissue samples for diagnostic and predictive examinations, particularly for small biopsy and cytology specimens. Therefore, each institution needs to develop a diagnostic approach requiring close communication between the pulmonologist, radiologist, pathologist, and oncologist in order to preserve sufficient biopsy materials for molecular analysis as well as to ensure rapid diagnosis. Currently, personalized medicine in NSCLC is based on the histologic subtype and molecular status. This review summarizes strategies for tissue acquisition, histologic subtyping and molecular analysis for predictive testing in NSCLC.

Regulated Expression of Nebulin by Transfection of Green Fluorescent Protein-Tagged Nebulin Fragments in Cultured Chicken Myoblast

  • Park, Su-Jung;Kim, Ji-Hee;Ko, Han-Suk;Kim, Chong-Rak;Kim, Han-Do;Kang, Ho-Sung
    • Biomedical Science Letters
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    • v.7 no.4
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    • pp.167-172
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    • 2001
  • Nebulin is an approximately 700 kDa filamentous protein in vertebrate skeletal muscle. It binds to the Z line and also binds side-by-side to the entire thin actin filament in a sarcomere. The correlation of nebulin size with thin filament length have led to the suggestion that nebulin acts as a molecular ruler for the length of thin filaments. The C-terminal part of human nebulin is anchored in the sarcomeric Z-disk and contains an SH3 domain. SH3 domains have been identified in an ever-increasing number of proteins important for a wide range of cellular processes, from signal transduction to cytoskeleton assembly and membrane localization. However, the exact physiological role of SH3 domains remains, in many cases, unclear. To explore the role of nebulin SH3 in the cytoskeletal rearrangement that accompanies myoblast differentiation, we transfected sense and antisense nebulin SH3 domain fused to enhanced green fluorescent protein in myoblast. Cells expressing nebulin SH3 fragment showed decrease of cell-cell adhesion, and cells transfected with antisense nebulin SH3 gene showed a rounded cell morphology and loss of cell-matrix adhesion. No alteration in cell shape and differentiation were observed in control cells expressing enhanced green fluorescent protein. Perturbation of nebulin altered the cell shape and disrupted cell adhesion in myoblast, demonstrating that nebulin can affect cytoskeleton rearrangement.

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Comparative RFLP Analysis of Chromosome 2M of Aegilops comosa Sibth et Sm. Relative to Wheat (T. aestivum L.)

  • Park, Y. J.;Shim, J. W.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.43 no.2
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    • pp.120-123
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    • 1998
  • Based on the co-linearity in the Triticeae, comparative RFLP analysis of 2M chromosome of Ae. comosa Sibth et Sm. was performed with 2MS and 2M additional lines of Triticum aestivum L. cv. Chinese Spring. Among the wheat RFLP probes conserved in the short arms of wheat chromosome 2, those above psr912 were located on the long arms of 2M in Aegilops comosa. The rest probes on the short arm and all the probe sequences on the long arm of group 2 chromosome in wheat were conserved on the equivalent chromosomal position in Aegilops comosa. So, it is apparent that some chromosomal segment from the short arm had been transferred to long arm while reconstructing 2M chromosome relative to wheat chromosomes. The break-point was located between psr912 and psr131 of the short arm. This rearrangement of chromosome 2M might be a molecular evidence of the M genome speciation from an ancestral type.

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A study on the stamp-resist interaction mechanism and atomic distribution in thermal NIL process by molecular dynamics simulation (분자동역학 전산모사를 이용한 나노임프린트 리소그래피 공정에서의 스탬프-레지스트 간의 상호작용 및 원자분포에 관한 연구)

  • Yang, Seung-Hwa;Cho, Maeg-Hyo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.343-348
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    • 2007
  • Molecular dynamics study of thermal NIL (Nano Imprint Lithography) process is performed to examine stamp-resist interactions. A layered structure consists of Ni stamp, poly-(methylmethacrylate) thin film resist and Si substrate was constructed for isothermal ensemble simulations. Imposing confined periodicity to the layered unit-cell, sequential movement of stamp followed by NVT simulation was implemented in accordance with the real NIL process. Both vdW and electrostatic potentials were considered in all non-bond interactions and resultant interaction energy between stamp and PMMA resist was monitored during stamping and releasing procedures. As a result, the stamp-resist interaction energy shows repulsive and adhesive characteristics in indentation and release respectively and irregular atomic concentration near the patterned layer were observed. Also, the spring back and rearrangement of PMMA molecules were analyzed in releasing process.

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Bacillus anthracis Spores Influence ATP Synthase Activity in Murine Macrophages

  • Seo, Gwi-Moon;Jung, Kyoung-Hwa;Kim, Seong-Joo;Kim, Ji-Cheon;Yoon, Jang-Won;Oh, Kwang-Keun;Lee, Jung-Ho;Chai, Young-Gyu
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.778-783
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    • 2008
  • Anthrax is an infectious disease caused by toxigenic strains of the Gram-positive bacterium Bacillus anthracis. To identify the mitochondrial proteins that are expressed differently in murine macrophages infected with spores of B. anthracis Sterne, proteomic and MALDI-TOF/MS analyses of uninfected and infected macrophages were conducted. As a result, 13 mitochondrial proteins with different expression patterns were discovered in the infected murine macrophages, and some were identified as ATP5b, NIAP-5, ras-related GTP binding protein B isoform CRAa, along with several unnamed proteins. Among these proteins, ATP5b is related to energy production and cytoskeletal rearrangement, whereas NIAP-5 causes apoptosis of host cells due to binding with caspase-9. Therefore, this paper focused on ATP5b, which was found to be down regulated following infection. The downregulated ATP5b also reduced ATP production in the murine macrophages infected with B. anthracis spores. Consequently, this study represents the first mitochondrial proteome analysis of infected macrophages.

Molecular Distribution depending on the Cooling-off Condition in a Solution-Processed 6,13-Bis(triisopropylsilylethynyl)-Pentacene Thin-Film Transistor

  • Park, Jae-Hoon;Bae, Jin-Hyuk
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.3
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    • pp.402-407
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    • 2014
  • Herein, we describe the effect of the cooling-off condition of a solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) film on its molecular distribution and the resultant electrical properties. Since the solvent in a TIPS-pentacene droplet gradually evaporates from the rim to the center exhibiting a radial form of solute, for a quenched case, domains of the TIPS-pentacene film are aboriginally spread showing original features of radial shape due to suppressed molecular rearrangement during the momentary cooling period. For the slowly cooled case, however, TIPS-pentacene molecules are randomly rearranged during the long cooling period. As a result, in the lopsided electrodes structure proposed in this work, the charge transport generates more effectively under the case for radial distribution induced by the quenching technique. It was found that the molecular redistribution during the cooling-period plays an important role on the magnitude of the mobility in a solution-processed organic transistor. This work provides at least a scientific basis between the molecular distribution and electrical properties in solution-processed organic devices.

Gametophytic Abortion in Heterozygotes but Not in Homozygotes: Implied Chromosome Rearrangement during T-DNA Insertion at the ASF1 Locus in Arabidopsis

  • Min, Yunsook;Frost, Jennifer M.;Choi, Yeonhee
    • Molecules and Cells
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    • v.43 no.5
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    • pp.448-458
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    • 2020
  • T-DNA insertional mutations in Arabidopsis genes have conferred huge benefits to the research community, greatly facilitating gene function analyses. However, the insertion process can cause chromosomal rearrangements. Here, we show an example of a likely rearrangement following T-DNA insertion in the Anti-Silencing Function 1B (ASF1B) gene locus on Arabidopsis chromosome 5, so that the phenotype was not relevant to the gene of interest, ASF1B. ASF1 is a histone H3/H4 chaperone involved in chromatin remodeling in the sporophyte and during reproduction. Plants that were homozygous for mutant alleles asf1a or asf1b were developmentally normal. However, following self-fertilization of double heterozygotes (ASF1A/asf1a ASF1B/asf1b, hereafter AaBb), defects were visible in both male and female gametes. Half of the AaBb and aaBb ovules displayed arrested embryo sacs with functional megaspore identity. Similarly, half of the AaBb and aaBb pollen grains showed centromere defects, resulting in pollen abortion at the bi-cellular stage of the male gametophyte. However, inheritance of the mutant allele in a given gamete did not solely determine the abortion phenotype. Introducing functional ASF1B failed to rescue the AaBb- and aaBb-mediated abortion, suggesting that heterozygosity in the ASF1B gene causes gametophytic defects, rather than the loss of ASF1. The presence of reproductive defects in heterozygous mutants but not in homozygotes, and the characteristic all-or-nothing pollen viability within tetrads, were both indicative of commonly-observed T-DNA-mediated translocation activity for this allele. Our observations reinforce the importance of complementation tests in assigning gene function using reverse genetics.