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Supercon Inc. has fabricated two 200-mm. multifilamentary billets of niobium-titanium wire for winding into a magnet for GE Medical Systems' magnetic resonance imagers. The superconductors, which were prepared via the artificial pinning center process, demonstrated 'excellent piece length and high critical current densities.' In contrast, the magnets exhibited higher drift levels due, it is assumed, to higher joint resistivity, poor filament quality or flux creep.

A 0.5T, 95cm warm bore, cryogen-free superconducting magnet for whole body MRI has been developed and tested. By using Nb3Sn tape superconductor, this magnet is designed to meet the same performance requirement as existing helium cooled MRI magnets. Persistent operation with drift rate less than 0.1ppm/hour and a stable 5.6ppm field homogeneity in a 30cmx40cm cylindrical volume was achieved in October of 1992. The magnet is cooled and maintained at the temperature of about 10K by a Gifford McMahon(G-M) cryocooler. High quality images were produced by using this magnet with the 0.5T GE SIGNA magnetic resonance imaging system.

Histamine, a biogenic amine, is a neurotransmitter in neurons and sensory receptors in invertebrates. Histamine has rarely been reported in bivalves. We used HPLC with pre-column derivatization using 2,3-naphthalenedicarboxaldehyde (NDA) as a fluorescent labeling agent to measure histamine in ganglia, and peripheral tissues of the oyster Crassostrea virginica . We also used Western Blot technique to look for the presence of a histamine receptor in the mantle rim. HPLC results found histamine present in ng amounts in both the cerebral and visceral ganglia, as well as the mantle rim and other peripheral tissues of C. virginica . The study confirms and quantifies histamine as an endogenous biogenic amine in C. virginica in the nervous system and innervated organs. Western Blot technique also identified a histamine H2-like receptor present in sensory tissue of the oyster's mantle rim.