| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
We study coupled Brownian-motor models (ratchet models) in this study. (1)First, one-dimensional models. which are models for acto-myosin molecular motors for muscle contraction, are investigated with computer simulation. In the model, Brownian motors are placed in one-dimension and coupled to the two nearest neighbor motors with a linear spring. We obtain the velocity of the string consisting of motors, and find that the velocity of the coupled system is faster than that of the uncoupled system. Moreover, the energy efficiency, that is, the ratio of the work done by the system to the energy injected externally, is calculated. The efficiency for the coupled system is also higher than that of the uncoupled system. (2)Secondly, we extend the above model to allow motion in two dimensional space in order to reproduce the results of experiments in the so-called motility assay, where actin filaments are placed on a slide glass which is covered with myosin molecules and the filaments move to a certain direction for an appropriate environmental condition if ATP is added to the system. From our computer simulation, we observe that the longer the actin filament of our model becomes, the more clearly the filament moves to a certain direction and that the velocity of the filament becomes fast with the increase of the equilibrium distance between two nearest-neighbor motors. (3)Finally, we try to segregate the mixture of particles with the oscillating ratchet mechanism. That is, we pour the mixture on a container with a asymmetric saw-tooth base oscillating vertically and each kind of particles moves to the mutually opposite direction with an appropriate condition. If we place two boxes at the right and left sides of the container and collect particles with them, the segregation of the mixture becomes possible. We ascertain the possibility from computer simulation with the aid of the event driven algorism.
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