A memory controller is associated with a remapping table to enable access to content in a memory system that includes asymmetric memory. The inventive method involves placement of a radiation producing target at the end of a vacuum drift tube and closer to and substantially in the center of a shield for blocking radiation emitted from the radiation producing target. Other aspects of the invention concern methods for modulating the immune response of a subject by the use of the conjugate, complexes comprising, the sphingoid-polyalkylamine conjugate in combination with a biologically active molecule capable of modulating an immune response of a subject, compositions comprising the conjugate as well as kits making use of said conjugate. The foundation can include a concrete foundation member or a foundation framework comprising a plurality of attachment members secured together by beams.