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The ryanodine receptor type 3 (RyR-3) functions as a Ca2+-induced Ca2+ release (CICR) channel and is distributed in a wide variety of cell types including skeletal muscle and smooth muscle cells, neurons, and certain non-excitable cells. However, the physiological roles of RyR-3 are totally unclear. To gain an insight into the function of RyR-3 in vivo, we have generated mice lacking RyR-3 by means of the gene targeting technique. The mutant mice thus obtained showed apparently normal growth and reproduction. Although Ca2+-induced Ca2+ release from intracellular Ca2+ stores of the mutant skeletal muscle differed in Ca2+ sensitivity from that of wild-type muscle, excitation-contraction coupling of the mutant muscle seemed to be normal. Moreover, we could not find any significant disturbance in the smooth muscle and lymphocytes from the mutant mice. On the other hand, the mutant mice showed increased locomotor activity, which was about 2-fold greater than that of the control mice. These results indicate that the loss of RyR-3 causes no gross abnormalities and suggest that the lack of RyR-3-mediated Ca2+ signaling results in abnormalities of certain neurons in the central nervous system.

This paper describes an automatic welding system that can simultaneously control the bead height and back bead shape during one-sided MAG welding with a backing plate. The system uses a high-speed rotating arc welding process together with an arc sensing technique for seam tracking and torch height control.The arc sensing technique is also used to detect variations in the groove shape. The detection mechanism is described in detail in this paper.The system further uses a newly developed welding parameter control method in which only the wire feedrate and welding voltage are adaptively controlled, the other welding conditions being kept constant. This method is able to keep the bead height constant and retain the back bead shape even if the groove shape changes.Initial welding experimental results have shown the system to be effective and satisfactory for controlling the weld bead shape in one-sided GMAW (MIG/MAG) with a backing plate.

The chaotic oscillation of a domain wall is investigated by computer simulation. The bifurcation diagrams of the wall velocity and the power spectrum are calculated on the frequency of the external magnetic field. The Feigenbaum scenario by period doubling bifurcation is found to be one of the routes to chaos in this system.