Funding is requested for an instrumentation upgrade that would allow converting our T12 electron microscope into a more robust, higher throughput, and more efficient instrument for data collection under cryo-conditions. At present, this electron microscope is already set up for cryo-imaging but performance is dissatisfying. The high user demands, the complexity of the samples used, and the imaging approaches used require much more robust and reproducible sample preparation techniques and a much better (and faster) vacuum recovery system. [unreadable] [unreadable] The user base is large and diverse, representing the Burnham Institute for Medical Research, The Scripps Research Institute, Yale University, University of Vermont, University of Virginia School of Medicine, St. Jude Children's Research Hospital, and Stowers Institute for Medical Research. The electron cryo-microscopy experiments performed by these users provide critical data for projects supported by grants from NCI, NIAID, NHLBI and NIGMS. Eight projects from major users are highlighted in section B of this proposal and represent disease oriented research in developmental biology, cardiology, inflammation, vascular occlusion, tumor angiogenesis and metastasis, and infectious diseases. Institutional commitment to this initiative is substantial as described in the letters from the Institute's Executive Vice President and Chief Operating Officer, as well as from the Director of Facilities and Maintenance. [unreadable] [unreadable] [unreadable]