| Project/Area Number |
10650889
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | Nara Medical University (1999)
Shimane University (1998) |
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Principal Investigator |
OSAKI Shigeyoshi Nara Medical University, Department of Chemistry, Professor, 医学部, 教授 (90273911)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Spider / UV-irradiation / Dragline / Mechanical Measurement / Breaking Strength / Elastic Limit Strength / Safety / Degradation / 蜘蛛の糸 / 紫外線 / 新素材 / 力学的 / 光学的 |
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| Research Abstract |
It is interesting to study the effects of ultraviolet rays upon the physical properties of spider silks because the ultraviolet (UV) rays are usually irradiated to the orb-web outdoors. Especially, it is important to measure the mechanical properties of dragline before and after the UV-irradiation to study the effects of the irradiation.
The samples used here were the draglines from Nephila clavata at different stages of growth. The breaking strength and the elastic limit strength were determined from the stress-strain curve of dragline. The fine structures were also observed by electron microscope to determine the diameter of cross section of dragline.
The author measured the mechanical properties of dragline at different stages of spider's growth before the UV were not incident. The safety coefficient, which is defined as the ratio of the elastic limit strength to the spider's weight, was determined to be about 2 for mature spiders and to be about 3 for immature spiders.
UV-irradiation decreased the breaking strength while it did not change the elastic limit strength even after the UV-irradiation of a long time. It was made clear that the UV-irradiation decomposed the protein molecules constituting dragline and might decrease the molecular weight.
The present study shows that the spider silks are stronger to the UV-rays than the silks from silkworm and that they are stronger for juvenile spiders than form mature ones.
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