An optical waveguide includes a printed circuit board, a waveguide, a light emitter, a light receiver, a transparent driver, and a transparent processor. A pair of limb supports are positioned on the base, one to immobilize an arm and the other a leg of the subject. The hydrogel is capable of directly gelling an ionic liquid without other solvent such as water when causing gelation. The set of signatures are aligned to the beginning of an OS file system-level object and stored in a memory location, such as a cache, along with file system information relating to the write operation and to the file system-level object that the data is written into.