• Title/Summary/Keyword: Oligomers

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The Preparation of Crystalline Mannobiose from Brown Copra Meal Using the Enzyme System and Yeast Fermentation

  • Park, Gwi-Gun;Chang, Hak-Gil
    • Journal of Microbiology and Biotechnology
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    • v.3 no.3
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    • pp.194-198
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    • 1993
  • ${\beta}-1$, 4-Mannobiose was prepared by the enzymatic hydrolysis of brown copra meal and the subsequent elimination of mono-saccharides from the resultant hydrolysate with a yeast. The enzyme system hydrolyzed brown copra meal and produced monosaccharides and $\beta$-1, 4-mannobiose without other oligomers at the final stage of the reaction. Brown copra meal (30 g) was hydrolyzed at $50^{\circ}^C$ and pH 5 for 48 hr with the crude enzyme solution (300 ml) from Penicillium purpurogenum. By the elimination of monosaccharides from the hydrolysis products with a yeast (Candida parapsilosis var. komabaensis k-75), 5.2 g of crystalline mannobiose was obtained without the use of chromatographic techniques. After 50 hours of yeast cultivation, the total sugar content fell from 3.5% to 2.4%, and the average degree of polymerization rose from 1.8 to 2.2.

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Isolation of the Agarolytic Bacterium Vibrio cyclotrophicus DAG-130 from Abalone Gut

  • Meinita, Maria Dyah Nur;Luyen, Hai-Quoc;Hwang, Seon-Yeong;Kang, Ji-Young;Jin, Deuk-Hee;Hong, Yong-Ki
    • Fisheries and Aquatic Sciences
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    • v.11 no.2
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    • pp.76-81
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    • 2008
  • We isolated 1,916 strains of bacteria from gut and feces of abalone. The most active agarolytic bacterium, DAG-130, was identified from the gut of the abalone Haliotis gigantea. Of the bacteria harbored by both H. discus hannai and H. gigantea, 59% were agarolytic. There was no significant difference in the number of agarolytic bacteria isolated from abalone fed on the seaweeds Gelidium amansii, Laminaria japonica, or Undaria pinnatifida. Of the agarolytic bacteria, 72% were isolated from the guts of all sources tested while 43% came from the feces. The strain DAG-130 showed 100% identity with the bacterium Vibrio cyclotrophicus based on phylogenetic analysis of l6S rDNA. The bacterium produced monomers and oligomers from the agar substrate.

Synthesis of Hard Coating Solution for Plastic Display Plate (플라스틱 디스플레이 기판용UV 하드 코팅 용액의 합성)

  • Back, Sung Kyun;Jang, Sun Ho;Cho, Ur Ryong
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.1
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    • pp.45-51
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    • 2017
  • Poly(urethane acrylate) siloxane oligomers with Interpenetrating polymer netwoked nanoparticles were prepared to synthesize hard coating solution by reaction with diisocyanates. The diisocyanate combined siloxane hard coating solution showed more flexibility than the siloxane solution. In addition, diisocyanate resulted in improvement of curl property and surface hardness in the siloxane solution. Of the used diisocyanates, isophorone diisocyanate and acryloyloxy ethyl diisocyanate were good for UV hard coating solution. This effect will decrease brittleness in the siloxane solution using for plastic display plate.

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Pixel-Isolation Walls of Liquid Crystal Display Formed by Anisotropic Photoreaction of the Prepolymers Containing Cinnamate Moiety

  • Jung, Eun-Ae;Sung, Shi-Joon;Cho, Kuk-Young;Kim, Dae-Hwan;Son, Dae-Ho;Kang, Jin-Kyu
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.879-882
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    • 2009
  • A pixel isolation wall of liquid crystal display is fabricated by the anisotropic photoreaction of a cinnamate based prepolymer. The various oligomers containing a cinnamate moiety were synthesized and used for the formation of the pixel isolation wall. The anisotropic photoreaction of cinnamate moiety was closely related with the liquid crystal orientation at the polymer wall boundary.

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Preparation and Properties of UV Curable Hard Coating Materials on PET (자외선 경화형 고경도 PET 필름의 제조 및 특성)

  • Kim, Hyunjoon
    • Journal of the Semiconductor & Display Technology
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    • v.13 no.1
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    • pp.35-41
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    • 2014
  • UV curable transparent hard coating materials have been developed to improve the mechanical and optical properties of PET substrate. The coating materials were synthesized using various urethane acrylate oligomers, monomers, photo initiators, and leveling agents. The materials were coated on PET substrates and UV cured. The hard coated PET films were shown to have the good scratch resistance and transparency. When the urethane acrylate oligomer with more functional groups was introduced into the coating solution, the mechanical and optical properties were improved. However the higher concentration of 9-functional oligomer resulted in the decrease of workability. The addition of trimethylolpropane ethoxylate$(EO/OH)_9$ triacrylate(TMPETA) to coating solution improved the workability and properties. As a result, the UV cured film from the formulation of urethane acrylate oligomer with 9-functional groups, TMPETA as a monomer, IRACURE 754 as a photo initiator and BYK-340 as a leveling agent showed the best mechanical and optical properties in this study.

Synthesis and Properties of Soluble and Stable Silyl End-capped Bis-thienylanthracene Oligomers

  • Choi, Jung-Hei;Cho, Dae-Won;Sung, Nam-Kyoung;Jin, Sung-Ho;Yoon, Ung-Chan
    • Bulletin of the Korean Chemical Society
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    • v.28 no.11
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    • pp.1931-1938
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    • 2007
  • Analyzed are recent advances in design of novel boronared conjugates of synthetic and natural porphyrins and chlorins. These compounds showed high efficacy as cytotoxic agents for tumor cells in culture and as phototoxins in photodynamic therapy of tumor xenografts. Thus, boronated porphyrins and chlorins emerge as promising class of anticancer agents with potentially multiple advantages: the chemotherapeutic drugs alone and photo- and radiosensitizers in binary treatments.

Measurement of ileal permeability with different-sized polyethylene glycols (PEG 400, 600 and 1000)

  • Kim, Mee-Hye
    • Archives of Pharmacal Research
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    • v.19 no.2
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    • pp.100-105
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    • 1996
  • Polyethylene glycols (PEGs; 400, 600, and 1000) were used to study the molecular weight (MW) permeability dependence in the rat ileal mucosa. Absorption of the PEGs was measured by following their recirculation perfusion over a 3 hr collection period. HPLC methods were used to separate and quantitate the individual oligomers present in the solution of PEGs mixtures (MW range 330 to 1 1 22 D). In the range studied, a distinct molecular weight cutoff was not identified. Corrected for the length of ileum used in the study, over the molecular weight range 330 to 1122 D, the apparent permeability $(P_{app)$ of PEG ranged from $3.2\pm0.06\times10_{-5} cm/sec(mean\pmSEM, n=7)\; to\; 0.1\pm0.02\times10^{-5} cm/sec.$ Also, it was observed that the apparent permeability was inversely proportional to approximately $MW^{2.4}$.

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Ion-Selective Electrodes in Drugs Analysis: Verapamil-Selective Polymeric Membrane Electrodes Based on Calix[4]arene and Dibenzo-18-crown-6-ether Ionophores (이온 선택성 전극을 이용한 의약품 정량: Calix[4]arene과 Dibenzo-18-crown-6-ether에 의한 verapamil-선택성 polymeric membrane electrode)

  • 이은엽;김성진;김영학;김재현;허문회;안문규
    • YAKHAK HOEJI
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    • v.39 no.1
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    • pp.61-67
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    • 1995
  • PVC membrane electrodes based on the lipophilic neutral carrier, dibenzo-18-crown-6, cyclic oligomers of teit-butylphenol-formaidehyde condensates, calix[4]arenes as the active sensors for verapamil have been prepared and tested in a variety of plasticizers. At pH 5.0, the electrode exhibits a Nernstian response in the range of 10$^{-2}$~5$\times$10$^{-5}$ M verapamil with a slope of 49.1$\pm$0.5mV per concentration decade. The electrode constructed in this work can be used continuously for at least 1 month before any damage to the membrane occurs. And the analyses of the local anesthetic amine, which are good to select a specific compound in a mixed solution, were also accomplished by using of another neutral carrier, a DB18C6, for comparing with calix[4]arene.

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Disaggregation Simulation Analysis on Distinct Aβ40 Fibril Models

  • Cho, Tony;Yu, Youngjae;Shin, Seokmin
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.55-61
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    • 2016
  • $A{\beta}_{40}$ peptides form oligomers that later aggregate into a plaque, which is deemed to be a leading cause of Alzheimer's Disease. Its non-crystalline morphology has limited an understanding of comprehensive structural study. In this research, computational biomolecular simulations were performed in the following order: solvent and ion addition in a box, energy minimization of protein, equilibration, and periodic boundary condition disaggregation of a monomer from fibril. The result founded the two-fold model is 25% more stable in the simulation environment, and the steric zippers held on most tightly until 220 ps of simulation. The study supports the previous findings that two-fold aggregate $A{\beta}_{40}$ is more stable at 310 K and discusses further how much contribution steric-zipper and hydrogen bonding are making.

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