The present invention provides a compound of the formula or a pharmaceutically acceptable salt or solvate thereof, wherein the various moieties are as defined in the specification. A method of managing access to a database is provided. A separate end piece can be provided on each of a pair of toy vehicles or each vehicle can be provided with both. The teeth include an outer core portion arranged radially outward from an outer circumference of the hub, and an inner core portion arranged radially inward from the outer core portion. The composition has good detergency properties, the use of which promotes fuel savings.