Robert W. O'Connell

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A new method to measure rotating frame relaxation and to create contrast for MRI is introduced. The technique exploits relaxation along a fictitious field (RAFF) generated by amplitude- and frequency-modulated irradiation in a subadiabatic condition. Here, RAFF is demonstrated using a radiofrequency pulse based on sine and cosine amplitude and frequency(More)
BACKGROUND After an aneurysmal subarachnoid hemorrhage, cerebral microcirculatory changes occur as a result cerebral vasospasm. The objective of this study is to investigate, with a computational model, how various degrees of vasospasm are influenced by increasing the mean blood pressure and decreasing the blood viscosity. METHODS Using ANSYS CFX(More)
We describe a fundamentally different approach to MRI referred to as SWIFT (sweep imaging with Fourier transformation). SWIFT exploits time-shared RF excitation and signal acquisition, allowing capture of signal from spins with extremely short transverse relaxation time, T(2)*. The MR signal is acquired in gaps inserted into a broadband frequency-swept(More)
Surface organic residues inhibit the extraordinary electronic properties of graphene, hindering the development of graphene electronics. However, fundamental understanding of the residue morphology is still absent due to a lack of high-throughput and high-resolution surface characterization methods. Here, we demonstrate that secondary electron (SE) imaging(More)
The globular cluster ! Centauri contains the largest known population of very hot horizontal branch (HB) stars. We have used the Hubble Space Telescope to obtain a far-UV/optical color-magnitude diagram of three elds in ! Cen. We nd that over 30% of the HB objects are \extreme" HB or hot post-HB stars. The hot HB stars are not concentrated toward the(More)
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