An apparatus, method and system is provided for generating an optical code where a portion of the information stored in the optical code is encrypted prior to being stored in the optical code. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the treatment of such diseases in which the beta-secretase enzyme is involved. The bed sheet clamp features a simple structure. In some embodiments, a high-performance, transactional filestore is also provided to minimize the latency of small, synchronous writes to disk. Aeration efficiency and contamination resistance are thereby improved.