| Project/Area Number |
02452096
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
材料力学
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| Research Institution | Hokkaido University |
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Principal Investigator |
HAYASHI Kozaburo Hokkaido Univ., Res. Inst. of Appl. Elect., Professor, 応用電気研究所, 教授 (90026196)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Noritaka Hokkaido Univ., Res. Inst. of Appl. Elect., Research Associate, 応用電気研究所, 助手 (40210546)
MATSUMOTO Takeo Hokkaido Univ., Res. Inst. of Appl. Elect., Research Associate, 応用電気研究所, 助手 (30209639)
中村 孝夫 北海道大学, 応用電気研究所, 講師 (00142654)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥6,000,000 (Direct Cost: ¥6,000,000)
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| Keywords | Biomechanics / Living tissue / Growth and Deformation / Hypertension / Atherosclerosis / Aorta / Stress shielding / Patellar tendon / 生体組織 / 動脈壁 / 無負荷 |
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| Research Abstract |
1. Mechanical adaptation of rat aorta to hypertension.
The wall thickness significantly correlated with systolic blood pressure (Psys). The aortic hoop stress calculated for Psys was almost independent of Psys at 2-16 weeks after the operation. The incremental elastic modulus (H_<00>) of wall at Psys significantly correlated with Psys at 2-8 weeks. However, the correlation disappeared at 16 weeks after operation.
2. Mechanical properties of aortic walls in atherosclerotic rabbits.
There were no significant changes in the mechanical properties of walls if the percent fraction of the area involved with sudanophilic lesions on the luminal surface (As) was under 80%. Even if As was over 80%, only 20% of walls gave significantly higher H_<00> values compared with the remaining walls. Remarkable calcification was observed in the walls which had high H_<00> values.
3. Effects of stress shielding and restressing on the mechanical properties of rabbit patellar tendon.
The stress shielding decreased the tensile strength and tangent modulus markedly, for example to 10% of the control value by 2 weeks. The restressing increased the tensile strength and tangent modulus gradually, for example to 50% of the control value after 2-week stress-shielding followed by 6-week restressing.
4. Effects of over-stressing on the mechanical properties of rabbit patellar tendon.
The over-stressing caused no significant changes in the mechanical properties, although the cross sectional area was increased significantly, for example to 150% of the initial area by the 6-week stress elevation, which means that the overstressing increases the maximum failure load of whole patellar tendon.
These results indicate that biological soft tissues adapt themselves to the changes of mechanical environment by altering the mechanical properties and/or tissue dimensions.
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