Major equipment is used on a shared basis in the Cancer Center. Shared equipment is a cost-effective way of providing major items of equipment, as it discourages unnecessary duplication and maximizes the use of expensive equipment. Sharing also facilitates interactions among research groups, encouraging new ideas and collaborations. Shared equipment is a major factor in the success of Cancer Center research programs. Acquisition of new instrumentation, and orderly replacement of shared equipment that is no longer functional, are important in maintaining the research programs of the Cancer Center. Costs of service contracts, maintenance, and replacement are shared among the CCSG, individual research grants, and Institute funds. Liquid nitrogen is supplied to shared cryo-freezers and to shared low oxygen tissue culture incubators from central stations.