北畑 裕之

© 15CBMS-0001. We report a droplet-based microfluidic method that can control chemical fluxes into/out of a microreactor. Our method is inspired by the universal molecular transportation systems in cells based on vesicular fusion and fission, such as endo- and exo-cytotic processes. This method allowed precise control of chemical fluxes, resulting in successful control of chemical oscillation far from equilibrium. We believe that this system brings innovations in chemical and biomedical studies in terms of dynamical control of self-organized phenomena far from equilibrium.

This paper theoretically describes calling behaviors of Japanese tree frogs Hyla japonica with a simple model of phase oscillators. Experimental analysis showed that while isolated single frogs called nearly periodically, a pair of interacting frogs called alternately. We model these phenomena as a system of coupled phase oscillators, where each isolated oscillator behaves periodically as a model of the calling of a single frog and two coupled oscillators shows antiphase synchronization, reflecting the alternately calling behavior of two interacting frogs. Then, we extend the model to a system of three oscillators corresponding to three interacting frogs and analyse the dynamics. We also discuss a biological meaning of the calling behaviors and its possible application to Artificial Life and Robotics. ©ISAROB 2007.

An alcohol (pentanol) droplet exhibits spontaneous motion on an aqueous solution, driven by a solutal Marangoni effect. We found that the mode of such droplet motion changes depending on the temperature of the aqueous phase. When the temperature of the aqueous phase is 20°C, a droplet with a volume of 1 μl exhibits vectorial motion, whereas when the temperature is 25°C, the droplet exhibits irregular motion. We discuss the mode change in relation to the solubility of pentanol in water.