• Title/Summary/Keyword: Molecular Characteristics

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Purification, Structural Characterization, and Biological Activity of Polysaccharides from Lentinus velutinus

  • Udchumpisai, Wascharin;Bangyeekhun, Eakaphun
    • Mycobiology
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    • v.48 no.1
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    • pp.51-57
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    • 2020
  • A polysaccharide (LVP) was purified from fruiting body of Lentinus velutinus by ethanol precipitation fractionation and DEAE and Sephadex G-100 column chromatography. The yield of purified polysaccharide was 0.025%. Molecular characteristics of LVP were determined by gel permeation chromatography, FT-IR spectroscopy, and thin-layer chromatography. Our results revealed that LVP is a polysaccharide composed of only glucose units, and has a molecular weight of 336 kDa. Biological activity assays indicated that LVP exhibits both cytotoxic and antioxidant activity. LVP showed specific cytotoxicity against cancer cells (HeLa and HepG2 cells), and alterations in cancer cell morphology were found after LVP treatment.

Analysis of Mechanical Behavior of Nanowire by $Nos\acute{e}-Poincar\acute{e}$ Molecular Dynamics Simulation ($Nos\acute{e}-Poincar\acute{e}$ 분자 동역학 알고리즘을 이용한 나노 와이어의 역학적 거동 해석)

  • Lee, Byeong-Yong;Cho, Maeng-Hyo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.506-511
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    • 2007
  • Mechanical behavior of copper nanowire is investigated. An FCC nanowire model composed of 1,408 atoms is used for MD simulation. Simulations are performed within NVT ensemble setting without periodic boundary conditions. $Nos\acute{e}-Poincar\acute{e}$ MD algorithm is employed to guarantee preservation of Hamiltonian and temperature. Numerical tensile tests of Nanowire are carried out with constant strain rate. Additionally, temperature and strain rate effects are considered. Stress-strain curve is constructed from the calculated Cauchy stresses and specified strain values. In (22,4,4) Copper nanowire, non-linear behavior appears around ${\epsilon}\simeq0.09.$ At this instance, starting of structural reorientations are observed. At the onset of reorientation, the modulus characteristics are also investigated.

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A Newly Recorded Sea Star of the Genus Marginaster (Asteroidea: Valvatida: Poraniidae) from the Korea Strait, Korea

  • Lee, Taekjun;Bae, Sungjun;Kim, Dae-Jin;Shin, Sook
    • Animal Systematics, Evolution and Diversity
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    • v.33 no.4
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    • pp.274-277
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    • 2017
  • A sea star was collected from the Korea Strait in the waters adjacent to eastern Jeju Island, Korea ($33^{\circ}39^{\prime}86^{{\prime}{\prime}}N$, $127^{\circ}33^{\prime}12^{{\prime}{\prime}}E$) at a depth of 92 m on November 5, 2016. This specimen was identified as Marginaster paucispinus Fisher, 1913, from the family Poraniidae of the order Valvatida, based on morphological characteristics. The genus Marginaster Perrier, 1881 and M. paucispinus, which were first reported in the South China Sea, are new to the Korean fauna. Partial sequences of mitochondrial COI and 16S ribosomal RNA of M. paucispinus were have been determined for the first time and were deposited in GenBank. They are the first molecular records for the genus Marginaster.

Characteristics of HOMO and LUMO Potentials by Altering Substituents: Computational and Electrochemical Determination

  • Kim, Young-Sung;Kim, Sung-Hoon;Kim, Tae-Kyung;Son, Young-A
    • Textile Coloration and Finishing
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    • v.20 no.5
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    • pp.41-46
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    • 2008
  • Recently, computational calculation of molecular energy potentials and electrochemical reduction/oxidation behaviors are of very importance in view point of prediction of dye's properties such as energy levels and bandgaps of absorption. This can be influenced by their different constituents or substituents in chromogen molecules. Structural conformations and properties with computational modeling calculation are numerically simulated, which are fully or partly based on fundamental laws of physics. In addition, cyclic voltammetric measurement was used to obtain the experimental redox potential values, which were compared to the computed simulation values.

Isolation and Characterization of Aquatic Humic Acid and Fulvic Acid (수질계의 Humic Acid와 Fulvic Acid의 분리 및 특성)

  • Rhee, Dong Seok
    • Analytical Science and Technology
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    • v.15 no.1
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    • pp.36-42
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    • 2002
  • The dissolved organic carbon extracted from groundwater is separated into humic acid and fulvic acid. They are characterized for their chemical composition, spectroscopic characteristics using UV/VIS, IR and solid state $^{13}C-NMR$ spectroscopy, proton exchange capacity and molecular size distribution. The results are comparable with the literature data. The study explains that the aquatic humic and fulvic acid in this experiment are site-specipic and polydisperse natural organic matter with considerable proton exchange capacity.

Recent Progress in Study and Development of Polymeric Scaffolds for Tissue Regeneration (조직재생을 위한 고분자 지지체의 최근 연구개발 동향)

  • Joung, Yoon-Ki;Park, Ki-Dong;Park, Kwi-Deok;Han, Dong-Keun
    • Journal of Biomedical Engineering Research
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    • v.29 no.4
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    • pp.255-266
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    • 2008
  • In tissue engineering, scaffolds play an important role in the growth of cells to 3-D organs or tissues. For the success of tissue engineering, they should be mimicked to meet the requirements of natural extracellular matrix (ECM) in the body, such as mechanical properties, adhesiveness, porosity, biodegradability, and growth factor release, etc. Contrary to other materials, polymeric materials are adequate to engineer scaffolds for tissue engineering because controlling the structure and the ratio of components and designing various shapes and size are possible. In this review, the importance, major characteristics, processes, and recent examples of polymeric scaffolds for tissue engineering applications are discussed.

Characteristics of Carbon Nanotube Oscillator for Embedded System (임베디드 시스템을 위한 탄소나노튜브 오실레이터의 특성 해석)

  • Lee, Jun-Ha
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.5
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    • pp.1150-1153
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    • 2008
  • The coupled oscillation of multi-walled carbon-nanotube (MWCNT) oscillators consisting of (5n, 5n) CNTs was investigated by molecular dynamics simulations. The results show that the inter-wall coupling leads to frequency splits. And there are consistently three primary frequency peaks for the quadric-walled, penta-walled and hexa-walled CNT oscillators. It is independent of the wall parameters, suggesting applications as triple-frequency generators. Furthermore, at least one of the primary frequencies of a MWCNT oscillator is lower than that of its double-walled counterpart.

Can we rejuvenate? Implications of biological aging research (우리는 다시 젊어질 수 있는가? 생물학적 노화 연구의 시사점)

  • Son, Youlim;Kim, Jae-Ryong
    • Journal of Yeungnam Medical Science
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    • v.34 no.1
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    • pp.1-10
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    • 2017
  • The life history of man is summarized as a birth-aging-disease-death. Man eventually ages and dies. How long can humans live? What is aging? Why do we age? Is aging inevitable? Can we rejuvenate? Recent researches on biological aging suggest that humans might overcome aging and rejuvenate. In this paper, we review the biologic characteristics of aging and the latest results of biological aging research, implicating that aging can be controlled, further treated, and that humans can ultimately be rejuvenated.

Biochemical and Molecular Insights into Bile Salt Hydrolase in the Gastrointestinal Microflora - A Review -

  • Kim, Geun-Bae;Lee, Byong H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.10
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    • pp.1505-1512
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    • 2005
  • Bile salt deconjugation is the most biologically significant reaction among the bacterial alterations of bile acids in the gastrointestinal tract of human and animal. The responsible enzyme, bile salt hydrolase (BSH), catalyzes the hydrolysis of glycineand/or taurine-conjugated bile salts into amino acid residues and deconjugated bile acids. Herein we review current knowledge on the distribution of BSH activity among various microorganisms with respect to their biochemical and molecular characteristics. The proposed physiological impact of BSH activity on the host animal as well as on the BSH-producing bacterial cells is discussed. BSH activity of the probiotic strains is examined on the basis of BSH hypothesis, which was proposed to explain cholesterol-lowering effects of probiotics. Finally, the potential applications of BSH research are briefly discussed.

A Study on Nano-Accelerometer based on Carbon Nanotube (탄소나노튜브 기반의 나노-가속도계에 관한 연구)

  • Song, Young-Jin;Lee, Jun-Ha
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.1
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    • pp.91-95
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    • 2009
  • We investigated the characteristics of a capacitive nano-accelerometer based on carbon nanotube by means of classical molecular dynamics simulations. The position of the telescoping nanotube was controlled by the externally applied force and the feedback sensing was achieved from the capacitance change. Considering energy dissipation, the oscillation features of the nano-accelerometers were similar, regardless of their initial displacements. The capacitance variations, which were almost linearly proportional to the applied acceleration, were monitored within an error tolerance.