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  • artificial seed  (3)
  • chitosan  (2)
  • Polypyrrole  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Preparation and characterization of covalently bonded biopolymer-polypyrrole hybrid materials (1999)
    Springer
    Journal of polymer research 6 (1999), S. 203-210 
    Details
    ISSN: 1572-8935
    Keywords: Biopolymers ; Polypyrrole ; Polymer hybrids ; Hybrid materials ; Collagen ; Chitosan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis of biopolymer-polypyrrole hybrid materials that can possess electrical conducting has been the focus of our laboratory. To date, we have only obtained intimate blends that at best, display ionic bonding interactions. In this paper we report on the preparation of biopolymer-polypyrrole hybrid materials with covalent bonding between the two polymer chains. This has been achieved by preparing several functionalized pyrrole monomers, followed by covalently bonding of these monomer to the biopolymer and finally, polymerizing the pyrrole monomer. The pyrrole monomers used were 4-(3-pyrrolyl)oxobutyric acid, 4-(3-pyrrolyl)butyric acid, 3-(3-pyrrolyl)propylamine and the biopolymers were collagen and chitosan. FTIR data show the presence of covalent bonding between the two polymer chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0089-9
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Alginate-chitosan coacervation in production of artificial seeds (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 449-454 
    Details
    ISSN: 0006-3592
    Keywords: artificial seed ; sodium alginate ; chitosan ; complex coacervation ; encapsulation ; embryoid viability ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Survival of secondary embryoids of winter oilseed rape (Brassica napus ssp. oleifera cv. Primor) has been used as an assay for the development of artificial seeds involving complex coacervation of alginate (polyanion) with chitosan (polycation). Germination frequency of 100% was achieved for encapsulated embryoids when alginate formed the inner matrix and chitosan the outer layer. When the matrix makeup was reversed, there was no germination of embryoids. The artificial seeds produced were hardened in dilute alkaline solutions of NaOH and Ca(OH)2. An optimum setting time could be selected based on a quantitative measurement of resistance of hardened capsules to compression and the germination frequency of the encapsulated embryoids. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260420407
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    High frequency production of embryos from liquid flask cultures of oilseed rape (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 54 (1997), S. 231-238 
    Details
    ISSN: 0006-3592
    Keywords: Brassica napus ssp. oleifera ; cell suspension ; somatic embryogenesis ; artificial seed ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: As part of the program to scale-up the production of artificial seeds of winter oilseed rape, Brassica napus ssp. oleifera, we established a liquid flask culture system that enables the high frequency production of freely suspended embryos. As many as 4000 embryos could be obtained from 1 mL packed-cell-volume of cells. For initiation of liquid flask cultures, four different types of callus tissues were used. Among them, the most embryogenic cell suspension cultures were obtained from spontaneous callus developed on the surface of secondary embryos precultured in medium supplemented with 2,4-dichlorophenoxyacetic acid (4.52 μM) and kinetin (0.46 μM) (type B callus). Growth curves of the cell suspension were determined and the cell suspension was able to grow in medium without plant growth regulators. Embryos were observed to developed directly from the cells without going through an obvious callus phase. When subcultured to agar medium containing 44.38 μM benzylaminopurine, about 43% of the embryos developed into plants. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 231-238, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Two-coat systems for encapsulation of Spathoglottis plicata (Orchidaceae) seeds and protocorms (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 59 (1998), S. 635-639 
    Details
    ISSN: 0006-3592
    Keywords: Spathoglottis plicata ; orchid ; encapsulation ; two-coat systems ; complex coacervation ; artificial seed ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Complex coacervation of alginate-chitosan and alginate-gelatin were used to develop two-coat systems for the encapsulation of Spathoglottis plicata seeds and protocorms (top-shaped structures formed after seed germination of orchids). Both the seeds and the protocorms could withstand the encapsulation treatments with high viability. About 54% of seeds and 40% of large protocorms (1.6-2.0 mm) were able to tolerate a 6-h desiccation treatment. However, viability of the small protocorms (0.7-0.9 mm) was greatly reduced if they were desiccated before encapsulation. Encapsulation after desiccation significantly increased the percentage viability of seeds and protocorms. Treatment with abscisic acid (ABA, 10-5 M) before desiccation and encapsulation resulted in high percentage viability in seeds and large protocorms whereas the small protocorms were found to be less tolerant to the treatments. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:635-639, 1998.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    γ Irradiation of chitosan (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 282-290 
    Details
    ISSN: 0021-9304
    Keywords: chitosan ; γ irradiation ; films ; main chain scission ; network structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Chitosan has potential biomedical applications that may require the final products to be sterilized before use. The γ irradiation of purified and highly deacetylated chitosan fibers and films at sterilizing doses (up to 25 kGy) caused main chain scissions. The viscosity average molecular weight of the polymer decreased with increasing irradiation dose, the radiation yields of scission being 1.16 in air and 1.53 in anoxia. Preirradiation application of a negative pressure of 100 kPa disrupted the network structure, which may have contributed to the greater radiation yield obtained by chitosan fibers in anoxia. Radiation induced scission of the chitosan chains resulted in a lower glass transition temperature (Tg), indicative of higher segmental mobility. The Tg was below ambient at an irradiation dose of 25 kGy in air. Irradiation in air improved the tensile strength of the chitosan film, probably due to changes in chain interaction and rearrangement. Irradiation in anoxia did not affect film properties significantly, partly because the preirradiation application of negative pressure had a negligible effect on the structure of the chitosan film. Polymer network structure and the irradiation conditions are therefore important determinants of the extent of radiation induced reactions in chitosan. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 282-290, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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