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1 Macleod, Robert S.Sensitivity and specificity of substrate mapping: An in silico framework for the evaluation of electroanatomical substrate mapping strategiesBackground - Voltage mapping is an important tool for characterizing proarrhythmic electrophysiological substrate, yet it is subject to geometric factors that influence bipolar amplitudes and thus compromise performance. The aim of this study was to characterize the impact of catheter orientation on...2014-01-01
2 Christensen, Douglas A.Ultrasound beam simulations in inhomogeneous tissue geometries using the hybrid angular spectrum methodThe angular spectrum method is a fast, accurate and computationally efficient method for modeling wave propagation. However, the traditional angular spectrum method assumes that the region of propagation has homogenous properties. In this paper, the angular spectrum method is extended to calculate u...2012-01-01
3 Normann, Richard A.Oscillations in rod and horizontal cell membrane potential: evidence for feed-back to rods in the vertebrate retina1. Rods and horizontal cells were studied with intracellular recordings in the retina of the toad, Bufo marinus; 161 cells were from the eyecup preparation and thirty were from the isolated perfused retina. 2. Of these cells, 39% exhibited either transient or sustained oscillations of membrane poten...Retina; Photoreceptors; Toads; Adaptation, Ocular1976
4 Gesteland, Raymond F.Processing of adenovirus 2-induced proteinsAnalysis of (35)S-methionine-labeled extracts of adenovirus 2-infected KB cells revealed 22 virus-induced polypeptide components. Most proteins of the virion were easily detected in extracts of whole cells labeled for short periods between 15 and 30 h after infection; however, several virion compone...Adenoviridae; Viral Proteins; Protein Precursors; Methionine; Mouth Neoplasms1973
5 Horch, Kenneth W.; Lawrence, Steve M.; Dhillon, Gurpreet S.Acute peripheral nerve recording characteristics of polymer-based longitudinal intrafascicular electrodesWe examined the recording characteristics of two different types of polymer-based longitudinal intrafascicular electrodes (LIFEs) in peripheral nerve: single-stranded (s-polyLIFEs) and multistranded (m-polyLIFEs). Recordings were also made from Pt-Ir wire-based electrodes (PtIrLIFEs) as a control. T...Sciatic Nerve; Intrafascicular Electrodes, Peripheral Nerve Recording2004
6 Christensen, Douglas A.Acoustic droplet vaporization, cavitation, and therapeutic properties of copolymer-stabilized perfluorocarbon nanoemulsionsAcoustic and therapeutic properties of Doxorubicin (DOX) and paclitaxel (PTX)-loaded perfluorocarbon nanoemulsions have been investigated in a mouse model of ovarian cancer. The nanoemulsions were stabilized by two biodegradable amphiphilic block copolymers that differed in the structure of the hydr...Cancer therapy; Targeted drug delivery; Nanobubbles; Ultrasound; Perfluoropentane2009
7 Christensen, Douglas A.Ultrasound beam propagation using the hybrid angular spectrum methodWe introduce a fast and accurate numerical method for simulating the propagation of an ultrasound beam inside inhomogeneous tissue for mapping beam absorption, refraction and diffraction in the body. The technique, called the hybrid angular spectrum method, is an extension of the angular spectrum m...Ultrasound beam propagation; Medical ultrasound; Inhomogeneous tissue; Beam simulation2008-08
8 Normann, Richard A.Control of retinal sensitivity. I. Light and dark adaptation of vertebrate rods and conesRods and cones in Necturus respond with graded hyperpolarization to test flashes spanning about 3.5 log units of intensity. Steady background levels hyperpolarize the rods, and the rod responses become progressively smaller as background level is increased. In cones, higher background levels reduce...Retina;Light and Dark Adaptation; Recepters; Bipolars; Ganglion Cells1974
9 Horch, Kenneth W.Intraspinal microstimulation using cylindrical multielectrodesA cylindrical multielectrode system specifically designed for intraspinal microstimulation was mechanically and electrically evaluated in the ventral horn of the feline lumbo-sacral spinal cord. Electrode insertions proved to be straight as evaluated from radiographs. Impedances were measured in s...Cylindrical multielectrode; Microstimulation; Neural prosthesis; Current distance constants; Electrode array; Spinal cord stimulation2006-02
10 Christensen, Douglas A.; Furse, Cynthia M.Problem and treatment of DC offsets in FDTD simulationsThis paper discusses the causes of and some solutions to the commonly observed problem of dc field offsets in finite-difference time-domain (FDTD) simulations. DC electric and magnetic field offsets are shown to be valid calculated responses of the modeled systems, resulting from interaction betwee...Finite-difference time-domain method; Direct current offsets; Waveforms2000-08
11 Normann, Richard A.; Chandler, John P.Effects of calcium ions on L-type horizontal cells in the isolated turtle retinaA technique by which the retina can be isolated from the turtle eye is described. Scanning electron microscopy revealed morphological variability between preparations and also between regions of the same one. Large areas were often totally free of any pigment epithelial cells, yet contained a high p...Retina; Calcium; Horizontal Cell; Turtle1990
12 Normann, Richard A.Signal transmission from red cones to horizontal cells in the turtle retina1. Intracellular recordings were made from L-type horizontal cells in the retina of the turtle Pseudemys scripta elegans. The responses were evoked by 500 msec pulses of 'white' light. 2. L-type horizontal cells were classified as either, 'small receptive field' s.r.f. or 'large receptive field' l.r...Turtles; Synapses; Retina; Photoreceptors1979
13 Horch, Kenneth W.Muscle recruitment through electrical stimulation of the lumbo-sacral spinal cordThe goal of this study was to determine the feasibility of producing graded muscle contraction in individual muscles or muscle groups by electrically stimulating motor neurons in the lumbo-sacral spinal cord. Recruitment curves were obtained for quadriceps, tibialis anterior and triceps surae/pl...Functional neuromuscular stimulation (FNS); Motor pools, Muscle recruitment, Spinal cord stimulation2000
14 Gesteland, Raymond F.; Weiss, Robert B.Efficient shine- Dalgarno sequence but not translation is necessary for LacZ mRNA stability in Escherichia coliThe 5' ends of many bacterial transcripts are important in determining mRNA stability. A series of Shine-Dalgarno (SD) sequence changes showed that the complementarity of the SD sequence to the anti-SD sequence of 16S rRNA correlates with lacZ mRNA stability in Escherichia coli. Several initiation c...Protein Biosynthesis; Ribosomes; Escherichia coli; Shine-Dalgarno Sequence1994
15 Horch, Kenneth W.Classification of action potentials in multi unit intrafascicular recordings using neural network pattern recognition techniquesNeural network pattern-recognition techniques were applied to the problem of identifying the sources of action potentials in multi-unit neural recordings made from intrafascicular electrodes implanted in cats. The network was a three-layer connectionist machine that used digitized action potenti...Intrafascicular electrodes; Multi-unit neural activity; Artificial neural networks1994
16 Horch, Kenneth W.; Christensen, Douglas A.Accelerated 4-year bachelors/masters degree program in biomedical engineeringIn response to the need for providing advanced engineering education in a shorter time period than is currently possible by traditional curricula, we have created an Accelerated Dual Degree program in biomedical engineering. The purpose of this pilot program is to attract the brightest students, g...Accelerated dual-degree program2002
17 Horch, Kenneth W.Closed loop control of ankle position using muscle afferent feedback with functional neuromuscular stimulationThis paper describes a closed-loop functional neuromuscular stimulation system that uses afferent neural activity from muscle spindle fibers as feedback for controlling position of the ankle joint. Ankle extension against a load was effected by neural stimulation through a dual channel intrafasc...Neuromuscular stimulation; Functional neuromuscular stimulation (FNS); Neural electrodes1996
18 Christensen, Douglas A.Resonant inductive applicator for neck hyperthermiaWe have designed and phantom tested an inductive applicator especially suited for producing hyperthermia in cancerous regions in the neck. The applicator is tuned to resonate near 27 MHz; its inductive nature has the advantage of efficient coupling to the irregular neck anatomy. An inhomogeneou...Hyperthermia applicator; Phantom tests1989
19 Hansen, Mark S.; Healy, Lindsey J.; Johnson, Christopher R.; Capecchi, Mario R.; Keller, Charles; Jones, Greg M.Virtual histology of transgenic mouse embryos for high-throughput phenotyping.A bold new effort to disrupt every gene in the mouse genome necessitates systematic, interdisciplinary approaches to analyzing patterning defects in the mouse embryo. We present a novel, rapid, and inexpensive method for obtaining high-resolution virtual histology for phenotypic assessment of mouse ...Forkhead Transcription Factors; Paired Box Transcription Factors2006
20 Gesteland, Raymond F.; Atkins, John F.; Felden, Brice; McCutcheon, John P.Probing the structure of the Escherichia coli 10Sa RNA (tmRNA)The conformation of the Escherichia coli 10Sa RNA (tmRNA) in solution was investigated using chemical and enzymatic probes. Single- and double-stranded domains were identified by hydrolysis of tmRNA in imidazole buffer and by lead(II)-induced cleavages. Ribonucleases T1 and S1 were used to map unpai...Covariation; Pseudoknot; Structural Probing; 10Sa RNA; tmRNA1997
21 Normann, Richard A.Functional reorganization of primary visual cortex induced by electrical stimulation in the cat.Compared to the high degree of plasticity observed in a juvenile, mature sensory cortices have long been held to be immutable but, recently, researchers have suggested some plasticity persists in the mature cortex. Cortical reorganization has particular saliency to the development of a cortically ba...Cat; Electrophysiology; Phosphene; Plasticity; Receptive Field; Striate Cortex2005
22 Horch, Kenneth W.Microfabricated cylindrical multielectrodes for neural stimulationThe effects of spinal cord injuries are likely to be ameliorated with the help of functional electrical stimulation of the spinal cord, a technique that may benefit from a new style of electrode: the cylindrical multielectrode. This paper describes the specifications for, fabrication techniques for...Cylindrical multielectrode; Depth electrodes; Impedance testing; Microelectromechanical systems (MEMS); Microstimulation; Impedance testing; Neural prosthesis2006-02
23 Christensen, Douglas A.Plasma-etched polymer waveguides for intrachip optical interconnectsOptical intrachip communication offers the potential advantages of high speed and lack of electrical interference. We report on progress made on an interconnect design using GaAs LEDs, polymer waveguides, and photodiodes in a silicon substrate. The polymer waveguides are fabricated in polyimide or p...Polymer waveguides; Intrachip interconnects; LEDs1998
24 Blumenthal, Donald K.; Underwood, Clayton J.Adaptation of the protein kinase filter paper assay to a 96-well microtiter format.The most widely used method for assaying protein kinase activities involves incorporation of radioactive phosphate into a protein or peptide substrate with subsequent binding or precipitaion of the radiolabeled substrate onto filter paper squares. We have adapted this assay for use with readily avai...Protein Kinase Activities; Filter Papers; Radioactive Phosphate1999-02-01
25 Horch, Kenneth W.Muscle recruitment with intrafascicular electrodesWe have studied muscle recruitment with Tefloninsulated, 25 pm diameter, Pt-Ir intrafasicular electrodes implanted in nerves innervating the gastrocnemius and soleus muscles of cats. The purpose of this study was to measure the performance of these bipolar electrodes, which had been designed to...Functional neuromuscular stimulation (FNS); Intrafascicular electrode1991
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