Biomedical 600 MHz High Field MR Spectroscopy and Imaging Magnet Upgrade - The 14T high-field vertical-bore NMR spectrometer and microimager has been a central facility for our institution across nearly four decades, making contributions to biomedical research in many fields including MR contrast agent development, bone mineral developmental biology, tissue pathology, biomaterials, cancer, dental implantology, metabolomics, aging, Alzheimer’s, cardiology, and others. The pioneering first demonstration of the use of high resolution magic angle spinning (HRMAS) in NMR spectroscopy for tissue pathology was carried out in this facility. Over the years it has evolved from a 9.4T/400 MHz instrument to a 14T/600 MHz instrument, with several console and probe upgrades. It has supported many millions of dollars of funded grants, and played a key role in the training of numerous students, fellows and faculty. It is one of the facilities that makes MGH unique in hospital-based magnetic resonance research. In addition to the existing R01s held by the current users, new projects that would be supported include the neurophysiological basis of circuit-specific laminar resting-state functional MRI; commensal redox metabolism in C. diff. infection prevention; and vascular calcification in atherosclerosis and valvular disease. The magnet of this equipment has been in operation for over 21 years without being shut down for maintenance, longer than most. Its nominal liquid helium consumption rate, although state of the art at the time of purchase, is now considered excessive. Recently, the magnet has exhibited a very high consumption rate, indicative of the need for maintenance. Although we are proceeding with the maintenance, the extraordinary cost of helium at its specified consumption rate is unsustainable, and will become even more so as time progresses. The magnet manufacturer is no longer in business, making maintenance increasingly difficult. The only viable solution is a replacement of the magnet, by far the most expensive and central component of the system. This would insure another two decades of operation, and the ability to get repair parts from or have it serviced by, a stable, global company, Bruker BioSpin. Most importantly, it would permit a dramatic factor of four reduction in helium consumption, with a concomitant reduction in operating cost. The purpose of this grant is to replace the old 14T magnet with a modern Bruker 14T magnet.