Tyrone O'Neill

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A rugged, high-throughput HPLC-MS-MS-based method, suitable for quantitation of norepinephrine (NE) in urine, has been developed. A rapid, batch-mode procedure utilizes alumina to isolate NE and its deuterated internal standard from urine. After release of NE, using dilute formic acid, samples are analyzed by isocratic reversed-phase ion-pair HPLC, with(More)
It was found in in vitro experiments performed on tissue phantoms that acoustic streaming in low attenuating fluid may dramatically reduce the temperature rise generated by ultrasound at the surface of bone, if the ultrasound path contains a low-attenuating-fluid/thin-soft-tissue/bone structure. The temperature rise at the surface of bone generated by a 3.5(More)
A stable-isotope based gas chromatography-tandem mass spectrometry-negative ion chemical ionization method was developed for the determination of norepinephrine (NE) levels in small volumes (25-100 microl) of plasma. NE was stabilized in plasma by the addition of semicarbazide and spiked with deuterium-labeled norepinephrine internal standard. The analytes(More)
The problem of formalising continuous change within reasoning about action systems such as the situation calculus has recently been receiving increasing attention ((Rei96], MS96]). In this paper we show that a long-existing systems theoretic reasoning methodology, that of Zeigler's DEVS (discrete event system speciication), not only subsumes the standard(More)
Temperature rise generated by focused ultrasound beams was tested on semipermanent tissue-bone phantoms. The phantoms were capped (sealed) plastic hollow cylindrical containers filled with tissue-mimicking material (TMM), in which were imbedded 25 microns diameter copper-constantan thermocouples (TC) and a piece of compact human or cow bone. The acoustic(More)
Imposing a markovian condition on the situation calculus enables the embedding of situation calculus theories into the DEVS (discrete event system speciication) modelling and simulation framework. DEVS has an algebraic formalism relying on classical systems theory, and has been used to good eeect in practical domains. The demonstrated correspondence between(More)
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