A neckable nonwoven web is provided with a central region and two edge regions, the central region being selectively easier to neck than the two edge regions. The mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by a light-emitting layer and no more than two hundred times the longest wavelength. A lip shaper may include one or more contouring elements that change the shape of an upper lip, for example. One important application is respiratory gatingtriggering of HIFU sonication for the treatment of moving organs. 2 or less obtained by a photoluminescence measurement, where \u201cA\u201d is the light-emission intensity in the 500-600 nm band, and \u201cB\u201d is the light-emission intensity at the GaN band-edge. A PWM control circuit is connected to drive the power MOSFET.