Daniel A. Porter

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Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response,(More)
Six affected members of two families with familial periodic cerebellar ataxia were relieved of their symptoms with oral acetazolamide. Phosphorus 31 (31P) nuclear magnetic resonance spectroscopy showed abnormal intracellular pH levels in the cerebellum of all subjects when they were not treated. These levels returned to normal with treatment. Cerebral pH(More)
We have studied the metabolism of compounds containing 31P in normal breast using magnetic resonance spectroscopy (MRS). Spectra were acquired from non-lactating pre-menopausal breast (n = 14 women), lactating breast (n = 8) and post-menopausal breast (n = 8). The standard acquisition protocol used a 5.5 cm surface coil with the volunteer prone to minimize(More)
D. A. Porter, R. M. Heidemann MR Applications Development, Siemens Medical Solutions, Erlangen, Germany Introduction Diffusion-weighted, single-shot EPI suffers from considerable susceptibility-based distortion artefact at 3T. Although the effects can be mitigated by using a partially parallel imaging (PPA) technique to reduce the effective echo-spacing(More)
Nuclear magnetic resonance (NMR) has become an important non-invasive investigative technique in medicine and biology. The most recent development has been the ability to perform magnetic resonance spectroscopy (MRS) in selected regions within the human body. Such volumes can be selected by techniques which fall into the following broad categories: surface(More)
We describe a method for determining the cytotoxic effect of soft contact lens care solutions. The method provides a means for the direct exposure of mammalian cells to solutions and to lenses that have been soaked in solutions. Cytotoxicity was indicated by significant increases in the number of dead cells relative to controls. The cytotoxicity of a test(More)
Introduction: Diffusion-weighted, readout-segmented EPI (rs-EPI) with parallel imaging and 2D navigator correction [1] can provide substantially improved image quality compared to single-shot EPI (ss-EPI) with parallel imaging. The technique achieves a reduction in susceptibility artefacts and T2 image blurring by allowing a very short echo-spacing, which(More)
The aims of this study were two-fold: to characterize the in vivo 31P NMR spectrum of human breast tumours by identifying the metabolites contributing to each peak; and to demonstrate changes in the detectability of the phosphodiester (PDE) peak at varying field strengths. This was achieved by obtaining 31P spectra from 23 patients in vivo at 1.5 T and also(More)
As clinical applications of MRS grow in number and complexity, there is a need for standardized methods for characterizing the performance of volume selection techniques. The results are presented of a thorough evaluation of a particular implementation of ISIS performed using a procedure which forms the basis of the method adopted by the European Community(More)