The present invention relates to a proteinaceous extract derived from tortoise spleen and to a tetrapeptide FTGN, which have stimulatory activity on hematopoietic cells. The system includes a plurality of rotatable parallel louvers. The first coil is configured to receive a first voltage based on an output of a switching circuit. DLL constantly responds to variations in operating condition of the memory device to keep the external and internal clock synchronized. The plurality of planet assemblies frictionally engaged with the first raceway and the second raceway for transferring power between the sun shaft and the outer ring member. At least one switch in each group is connected to at least two elements, with each of the two elements being connected to different switches of the other group of switches.