High-resolution solid-state 27A1 NMR spectra have been obtained from ALON, fl'-sialon and yttrium aluminate phases. The usefulness of 27A1 magic-angle spinning NMR in phase characterization is shown by comparing different preparations of the yttrium aluminates. The sensitivity of the 27A1 resonance position to the local environment means different units (e.g. AIN4, A104, AIO6) can readily be distinguished allowing oxynitride structures, containing elements of similar scattering factor, to be refined. This is exemplified for the fl'-sialon phase. For quadrupolar nuclei (nuclear spin, I >_ 1) such as 2VAl (I = ~), interaction with the local electric-field gradient can cause extensive broadening of the resonance such that the NMR spectrum may not precisely quantify the aluminium distribution.

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New magnetic forms of C60 have been identified which occur in the rhombohedral polymer phase. The existence of previously reported ferromagnetic rhombohedral C60 is confirmed. This property has been shown to occur over a range of preparation temperatures at 9 GPa. The structure is shown to be crystalline in nature containing whole undamaged buckyballs. Formation of radicals is most likely due to thermally activated shearing of the bridging bond resulting in dangling bond formation. With increasing temperatures this process occurs in great enough numbers to trigger cage collapse and graphitization. The magnetically strongest sample was formed at 800 K, and has a saturated magnetization at 10 K, in fields above 3 kOe, of 0.045 emu g-1.

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Background & Aims-Esophageal adenocarcinomas (EAC) are heterogeneous and often preceded by Barrett's esophagus (BE). Many genomic changes have been associated with development of BE and EAC, but little is known about epigenetic alterations. We performed *

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