The invention provides human oxidoreductases and polynucleotides which identify and encode OXRD. When the accessory unit is not required, the battery pack can be mounted directly on the tool for powering to tool and when the accessory unit is required the battery pack can be mounted on the accessory unit for powering the accessory unit and, when the accessory unit is mounted on the tool, for powering the tool via the accessory unit. The hinged mount includes a sample mounting portion, for holding a sample being processed in the vacuum enclosure, and a counterweight portion. Various techniques are provided for chilling the interior of the duct.