| Project/Area Number |
02808052
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生物物性学
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| Research Institution | Chiba University. |
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Principal Investigator |
SAKAKI Yo Chiba University, Faculty of Engineering, Professor., 工学部, 教授 (80005280)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1992: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Biogenic magnetic-sensor / Biogenic magnetic substance / Magnetic compass / Migration of salmon / 生体マグネタイト / 動物の磁気コンパス / 磁気センサ |
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| Research Abstract |
Techniques extracting and analyzing the components of magnetic particles in adult salmon and eggs are developed. The crystal shape and the composition of the materials are analyzed by using an electron microscope, electron diffraction method and electron dispersive X-ray analysis techniques. The crystal shape of the magnetic particle is of truncated octahedron and the main component of the crystal is iron. The iron content is also identified by using iron dyeing technique.
Study on the distribution of magnetic particles in the head of salmon shows that tissues including the most amount of particles are semicircular canals. These are organs governing the balance during motion, therefore, the existence of magnetic particles in these organs suggests that there is a candidate for magnetic sensor.
Magnetic particles similar to the ones in adult salmon are also discovered in eggs. This discovery shows that the magnetic sensory system would be inherited from adult salmon.
A model of magnetic sensory system for migration of salmon is proposed on the basis of the extracted organs, i.e. a closed chain of spherical magnets is arrayed elliptically. The behavior of model under application of static magnetic field is analyzed using finite element technique. The result shows that the maximum torque acting on each magnet sphere is generated on the magnetic particles, the magnetization of which is orthogonal to the applied field and the position of maximum torque changes according to th field direction.
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