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Mixing is essential for various microfluidic applications. In this study, we propose a mixer using Leidenfrost phenomena. That is, by using a pair of ratchets (whose directions are opposite each other), we showed that the Leidenfrost mixer can rotate a water droplet with the angular velocity of ∼30 rad/s and can mix the pearl pigment (whose diffusion coefficient is zero) rapidly.

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Liquid delivery systems are important in microfluidic applications. In this paper, we report a high-speed side-shooter using a simple platelike hot protrusion placed on the lower edge of a hot slope. In particular, we experimentally show that the side-shooter launches a droplet with a high speed (15 cm=s). We propose a simple model to explain the side-shooting phenomenon; i.e., the hot protrusion causes an increase in the surface energy due to the formation of a new folded surface, which results from a new Leidenfrost phenomenon coupled with the protrusion, and therefore, the droplet can be launched at a high speed on the hot slope with a low friction due to the ordinary Leidenfrost phenomenon. A comparison of the theoretical results with the experimental results shows that they are in good agreement with each other. We believe that our side-shooter will play an important role in microfluidics in the future.

Diversity in Phagocytic and microbicidal activities was investigated in heterophils and macrophages collected from various sites in chicks. The activities varied in the two kinds of phagocytes. In the macrophage lineage, alveolar macrophages showed significantly lower levels of activities than the other cells investigated (abdominal macrophages and monocytes). The results indicate that the maturity of the cells of macrophage lineage in chicks does not relate to the levels of phagocytic and microbicidal activities. This is emphasized by the relatively higher phagocytic activity found in monocytes of chicks. In heterophils, abdominal cells showed significantly higher phagocytic and microbicidal activity than peripheral blood cells. The factors responsible for the difference in activities in phagocytes of chicks are discussed.