A hair clip has a body of a resilient material and first and second claws. In one embodiment, the probe comprises emitters and detectors that are inclined at an angle of about 1 to about 30 degrees to a surface of the probe that contacts tissue. Further, the composition activates and improves the function of a brain including the ability to learn, memorize, and think, as well as providing other physiological benefits. The pressurized feed gas stream is expanded with the performance of external work in an expansion turbine 6 upstream of the main heat exchanger. The second semiconductor substrate is bonded to the silicon-containing structures of the first substrate at the upper surface.