A process to convert glycerin into propylene glycol and purifying the produced propylene glycol is described. A holding devices moving apparatus such as a conveyor, moves the plurality of item holding devices through an item loading station with the item receptacles being oriented at a first angle to the horozinal. Faulty rows identified in each memory portion during testing are recorded. The first flexible trim portion at least partially covers the first assist grip opening of the rigid trim portion. In operation, a new entry from the second data set is presented in the second data set display section in response to receiving a navigation command related to the second data set. The present invention also provides for implementing an interrupt-driven architecture into an implantable medical device.