Common Sleep Paralysis Causes: The Common Sleep Paralysis for most people, happens, during R.E.M. state, when the body releases hormones that paralyze the body to keep it from acting out dreams, thereby reducing any chances of physical harm during sleep.
Hybrid material. Hybrid materials are composites consisting of two constituents at the nanometer or molecular level. Commonly one of these compounds is inorganic and the other one organic in nature. Thus, they differ from traditional composites where the constituents are at the macroscopic (micrometer to millimeter) level.
1 Biological or synthetic material that takes the place of all or a portion of a body part - like a skin graft or joint prosthesis.  Therapeutic material that is not absorbed by, eliminated by, or incorporated into a body part - such as a radioactive implant, or orthopedic pins.