Abstract: An assistive device for persons with an injured or disabled leg includes a main body comprising a crutch to which is pivotally attached a supporting structure. To assist the person in walking, the device can be used as crutch in the known manner, and the supporting structure is maintained in the same plane as the crutch. When the person wishes to be seated, one end of the device is placed on the seat adjacent the person and the supporting structure of the device is pivoted out of the plane of the crutch to provide a support for the opposite end.

Abstract: Water treatment, e.g. antiscaling, polymer compositions are marked or labelled with activated groups which are attached to the polymer chain backbone by carbon-carbon bonds. These activated groups are subjected to color forming reactions, e.g. by reaction with a diazonium aromatic compound, thus enabling the polymers to be detected at very low concentrations in water.