A cleaning machine for cleaning a surface is provided. The pocket receives a support member which maintains the side wall of the bulk bag in an upright, open configuration. A system comprising cells exposed to fibronectin and caused to proliferate by the presence of tenascin are used as an in vitro method for screening possible anti-tumour agents. The control circuit is configured to generate a control signal having a first slew rate prior to the control signal crossing the conduction threshold and a second slew rate after the control signal has crossed the conduction threshold. A network browser delivers an information search request to the root server, which in response develops a profiled information search request.