There is provided a substrate material for an optical component for X-rays of wavelength \u03bbR. Similarly disclosed is a novel method of conditioning soccer players to improve their ability to score goals. The voltage regulator circuit also comprises an output node, a first power node, a second power node, and a driver that generates a driving current flowing toward the output node in response to the control signal. In some embodiments of the method, the nanofibrous layer is formed by electro-spinning at least one polymer on at least one side of the porous support layer.