The invention relates to a layer arrangement, a memory cell, a memory cell arrangement and a method for producing a layer arrangement. The housing elements include a pultruded panel body member having at least one edge, and a pultruded snap lock fitting on the edge adapted for fastenerless engagement with a complementary fitting on an adjacent panel body member. A conveyor that forms the bottom of the hopper uses a sealed drum motor housed in the drive roller to drive the conveyor. The control circuit generates control signals that control the regulators providing the power supply rails with a controlled rate of change such that asymmetry between the voltages of the power supply rail outputs during changes of the power supply rails is substantially reduced. Antibodies of the present invention can be used for diagnosis and treatment of diseases characterized by aberrant tsp50 expression.