Kondo Y.,Textile Research Institute of Gunma |
Annaka H.,Japan Institute for Environmental Sciences |
Fujita M.,Japan Institute for Environmental Sciences |
Kubokawa H.,Textile Research Institute of Gunma |
And 5 more authors.
Sen'i Gakkaishi | Year: 2011
We developed an effective system to eliminate microorganisms from environmental water using cationic polyester fibers. The polyester fibers were cationized by dipping with 1% Poly (diallyldimethyammonium chloride) solution. The zeta potential of polyester fiber particles and some bacteria was measured using microscopic electrophoresis. The mean zeta potential of regular polyester fiber particles was -25mV and cationic polyester fiber particles was +45mV. The mean zeta potential of the bacteria, Bacillus subtilis was -15mV, Escheria coli, -25mV Legionella pneumophila, -25mV. The microbial suspension is pumped through the cationic polyester fiber filter. Bacteria electro-adsorption to the cationic polyester fibers was examined by bioassay. Relatively large numbers of bacteria could be removed by adsorption to the cationic polyester fiber. It was observed by electron microscopy that the bacteria adsorbed on the surface of cationic polyester fibers.
Iizuka T.,Japan National Institute of Agrobiological Science |
Sezutsu H.,Japan National Institute of Agrobiological Science |
Tatematsu K.-I.,Japan National Institute of Agrobiological Science |
Kobayashi I.,Japan National Institute of Agrobiological Science |
And 18 more authors.
Advanced Functional Materials | Year: 2013
Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ohshima T.,Gunma University |
Kondo T.,Gunma University |
Kitajima N.,Gunma University |
Kitajima N.,Textile Research Institute of Gunma |
Sato M.,Gunma University
IEEE Transactions on Industry Applications | Year: 2010
In this paper, adsorption and nonthermal plasma decomposition of gaseous acetaldehyde were studied using barrier-discharge plasma reactor, in which fibrous activated-carbon textile (ACT) was used as both an electrode and adsorbent. The acetaldehyde molecule was adsorbed on ACT depending on the concentration of gaseous acetaldehyde. When acetaldehyde concentration was 500 ppm or lower, the amount of adsorbed acetaldehyde was estimated by Henry's equation. The adsorbed acetaldehyde on ACT sheet was decomposed by the barrier-discharge plasma generated by applying high-voltage ac regulated by a neon transformer. When 200 ppm of acetaldehyde was fed continuously to the plasma reactor, 30, 45, and 120 ppm of acetaldehyde remained, with applied voltage of 13, 10, and 5 kVp, respectively. We also checked electric energy efficiency on the decomposition of acetaldehyde. Although 10 or 13 kVp of plasma has the same energy efficiency, 5 kVp of plasma was less effective for the decomposition because of unstableness of plasma generation. These results suggested that 10 kVp or more high-voltage ac is suitable for the decomposition of acetaldehyde by using ACT as the high-voltage electrode. © 2010 IEEE.
Zhu Z.,Tokyo University of Agriculture and Technology |
Kikuchi Y.,Tokyo University of Agriculture and Technology |
Kojima K.,Japan National Institute of Agrobiological Science |
Tamura T.,Japan National Institute of Agrobiological Science |
And 3 more authors.
Journal of Biomaterials Science, Polymer Edition | Year: 2010
Regenerated silk fibroin fibers from the cocoons of silkworm, Bombyx mori, were prepared with hexafluoro solvents, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) or hexafluoroacetone-trihydrate (HFA), as dope solvents and methanol as coagulation solvent. The regenerated fiber prepared from the HFIP solution showed slightly larger tensile strength when the draw ratio is 1:3 than that of native silk fiber, but the strength of the regenerated fiber with draw ratio 1:3 from the HFA solution is much lower than that of native silk fiber. This difference in the tensile strength of the regenerated silk fibers between two dope solvents comes from the difference in the long-range orientation of the crystalline region rather than that of short-range structural environment such as the fraction of β-sheet structure. The increase in the biodegradation was observed for the regenerated silk fiber compared with native silk fiber. Preparations of regenerated silk fibroin fibers containing spider silk sequences were obtained by mixing silk fibroins and silk-like proteins with characteristic sequences from a spider, Naphila clavipes, to produce drag-line silk in E. coli in the fluoro solvents. A small increase in the tensile strength was obtained by adding 5% (w/w) of the silk-like protein to the silk fibroin. The production of silk fibroin fibers with these spider silk sequences was also performed with transgenic silkworms. Small increase in the tensile strength of the fibers was obtained without significant change in the elongation-at-break. © 2010 Koninklijke Brill NV, Leiden.