Biomedical Commons^™

Time Domain Dielectric Spectroscopy Analysis Of Hl-60 Cell Suspensions After Microsecond And Submicrosecond Pulsed Electric Fields, Allen Laurence Garner

Electrical & Computer Engineering Theses & Dissertations

Pulsed electric fields (PEF's) above a certain voltage threshold cause electroporation for microsecond pulses and intracellular effects for submicrosecond pulses. Models describing these effects often depend on the electrical properties of the cell, which are altered by the PEF. Time domain dielectric spectroscopy was used to provide data for these models and to measure changes in the conductivity of HL-60 cell suspensions due to single 50 μs and 10 ns PEF's of the same energy. For 1.1 kV/cm, 50 μs pulses, the conductivity rose within a minute after the pulse and dropped dramatically approximately forty minutes after the pulse. For …

An Investigation Into Non-Verbal Sound-Based Modes Of Human-To-Computer Communication With Rehabilitation Applications, Ted Burke

Conference Papers

During the course of our work in the National Rehabilitation Hospital in Ireland we have encountered patients who, while unable to speak, are capable of making reproducible utterances. We present techniques used to harness such utterances, in addition to whistling, as a means of communication and control. A simple technique for identifying the phonemes /o/ and /s/ (in single-symbol ARPAbet notation) is presented with applications. The use of pitch variation as a means of controlling a continuously variable parameter is described with two applications - a microcontroller based light dimmer switch and a computer program which facilitates mouse pointer control. …

The Effects Of Intense Submicrosecond Electrical Pulses On Cells, Jingdong Deng, Karl H. Schoenbach, E. Stephen Buescher, Pamela S. Hair, Paula M. Fox, Stephen J. Beebe

Bioelectrics Publications

A simple electrical model for living cells predicts an increasing probability for electric field interactions with intracellular substructures of both prokaryotic and eukaryotic cells when the electric pulse duration is reduced into the submicrosecond range. The validity of this hypothesis was verified experimentally by applying electrical pulses (durations 100 μs– 60 ns, electric field intensities 3–150 kV/cm) to Jurkat cells suspended in physiologic buffer containing propidium iodide. Effects on Jurkat cells were assessed by means of temporally resolved fluorescence and light microscopy. For the longest applied pulses, immediate uptake of propidium iodide occurred consistent with electroporation as the cause of …

Modeling Intracranial Fluid Flows And Volumes During Traumatic Brain Injury To Better Understand Pressure Dynamics, Wayne W. Wakeland, James Mcnames, Mateo Aboy, D. Hollemon, Brahm Goldstein

Complex Systems Faculty Publications and Presentations

See additional files below for the Presentation.

We describe a computer model of intracranial pressure (ICP) dynamics that evaluates clinical treatment options for elevated ICP during traumatic brain injury (TBI). The model uses fluid volumes as primary state variables and explicitly models fluid flows as well as the resistance, compliance, and pressure associated with each intra - and extracranial compartment (arteries and arterioles, capillary bed, veins, venous sinus, ventricles, and brain parenchyma). The model evaluates clinical events and therapies such as intra - and extra-parenchymal hemorrhage, cerebral edema, cerebrospinal fluid drainage, mannitol administration, head elevation, and mild hyperventilation. The model …

Protocols For Disease Classification From Mass Spectrometry Data, Michael Wagner, Dayanand Naik, Alex Pothen

Mathematics & Statistics Faculty Publications

We report our results in classifying protein matrix-assisted laser desorption/ionizationtime of flight mass spectra obtained from serum samples into diseased and healthy groups. We discuss in detail five of the steps in preprocessing the mass spectral data for biomarker discovery, as well as our criterion for choosing a small set of peaks for classifying the samples. Cross-validation studies with four selected proteins yielded misclassification rates in the 10-15% range for all the classification methods. Three of these proteins or protein fragments are down-regulated and one up-regulated in lung cancer, the disease under consideration in this data set. When cross-validation studies …