Pharmaceutical, cosmetic and cosmeceutical compositions for topical application, containing, as an active ingredient, ammonium lactate andor any other alpha-hydroxy carboxylic acid andor salts thereof, processes of manufacturing these compositions and uses of these compositions in the treatment of medical and cosmetic conditions such as conditions associated with dry skin or scalp. The AD converter is configured to generate digital samples of voltage and current waveforms in a polyphase electrical system. The worktop includes opposing surfaces, each adapted to support at least one tool.