1997 Fiscal Year Final Research Report Summary
Relaxation process and dynamic heat capacity at the main transition of multi-lamellar vesicles of phosphatidylcholines
| Project/Area Number |
08454111
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物理学一般
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
EMA Kenji Tokyo Institute of Technology, Faculty of Science, Associate Professor, 理学部, 助教授 (80108183)
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| Co-Investigator(Kenkyū-buntansha) |
YAO Haruhiko Tokyo Institute of Technology, Faculty of Science, Research Associate, 理学部, 助手 (60212271)
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| Project Period (FY) |
1996 – 1997
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| Keywords | phospholipid / phase transition / relaxation process / dynamic heat capacity |
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| Research Abstract |
At the first stage of the research, the unilamellar vasicle samples with various alkyl chain length have been studied. For the measurements with chain length from 12 to 15, it was found that the heat anomaly accompanying the transition depends significantly on the chain length. It was also found that the unilamellar sample with chain length 12 shows an intermediate phase, which is similar to the multilamellar sample with the same chain length. A detailed analysis of these results has revealed that the observed chain-length dependence of the anomaly can be described with the modified Izuyama-Akutsu theory which has been proposed by the present authors to explain the vesicle-size dependence of the heat anomaly. It is expected from this modified theory that we can reach a critical point by adjusting the vesicle size and the chain length. We found that the sample with 30 nm diameter with chain length 15 is close to the critical point. A preliminary analysis shows that the critical exponent has a value alpha=0.5-0.7. More detailed analyzes are in progress. Although the measurement on multilamellar vesicles is behind the schedule, the results on unimalellar vesicles described above serve as a good background for future studies both on unilamellar and multilamellar vesicles.
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