1 - 25 of 127
Number of results to display per page
CreatorTitleDescriptionSubjectDate
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 Horch, Kenneth W.Changes in primary afferent depolarization of sensory neurones during peripheral nerve regeneration in the catI. Micro-electrode recordings were made from normal and regenerating sural nerve fibres in cats. Increases in the excitability of the central terminals of these fibres after conditioning stimulation of other sural nerve fibres were taken as evidence for primary afferent depolarization. 2. At all...Micro-electrode recording; Nerve regeneration; Primary afferent depolarization1981
4 Horch, Kenneth W.Tracking changes in action potential shapes in chronic multi-unit intrafascicular recordings using neural network pattern recognition techniquesA novel scheme is proposed to train an Artificial Neural Network (A") classifier, on a repeated basis, in order to track temporal changes in the shapes of the action potentials recorded through chronically implanted intrafascicular electrodes. This scheme uses classification results of the ANN Clas...Intrafascicular electrodes; Artificial neural network1994
5 Horch, Kenneth W.Control of ankle position using neural feedbackThis paper describes a closed loop control system that uses afferent neural activity from muscle spindle fibers as feedback for controlling ankle position. The gastrocnemius muscle was stimulated through a dual channel intrafascicular electrode implanted in a fascicle of the tibial nerve. Dual cha...Neuromuscular stimulation; Peripheral nerve; Joint angle1994
6 Christensen, Douglas A.Using the cardiovascular system to illustrate fundamental laws and principles in a freshman courseOur Fundamentals of Bioengineering I course is organized around key physical and engineering laws and principles. A semester-long Major Project is assigned which integrates many of these principles by modeling the human systemic cardiovascular system, using both Matlab computer analysis and assembly...Matlab2002
7 Horch, Kenneth W.Are the extrinsic muscles better suited for signaling joint angles or finger tip location?We used a biomechanical model of the human long finger to determine whether the extrinsic muscles are better suited for estimating the finger's joint angles or for estimating location of the finger tip. We found that two of the extrinsic muscles together could provide information sufficient to direc...Extrinsic muscles; Metacarpophalangeal joint; Biomechanical models1997
8 Horch, Kenneth W.Proposed specifications for a lumbar spinal cord electrode array for control of lower extremities in paraplegiaThe goal of the study was to provide specifications for a stimulating electrode array to be implanted in the lumbosacral spinal cord as part of a functional neuromuscular stimulation (FNS) system for control of lower extremity muscles in paralyzed individuals. Dual channel stimulation of the qua...Stimulating electrode array; FNS; Functional neuromuscular stimulation1997
9 Christensen, Douglas A.Ultrasound-enhanced localized chemotherapy of drug-sensitive and multidrug resistant tumorsA new modality of targeted tumor chemotherapy is based on the drug encapsulation in polymeric nanoparticles followed by a localized release at the tumor site triggered by focused ultrasound. Effect of 1 MHz and 3 MHz unfocused ultrasound applied locally to the tumor on the Doxorubicin (DOX) biodistr...Ultrasound-enhanced chemotherapy; Drug-resistant tumors; Biodistribution; Tumor sonication2006
10 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
11 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
12 Gesteland, Raymond F.; Atkins, John F.Origin and destiny of adenovirus proteinsLytic infection of human cells by adenovirus proceeds by a temporal expression of genes. Classically two phases have been defined: an early phase, which includes events occurring before the onset of DNA synthesis (8 hours), and a late phase, including events whose existence depends on the onset of...Protein Biosynthesis; DNA, Viral; Adenoviridae; RNA, Viral; Time Factors1975
13 Angelucci, Alessandra; Lund, Jennifer S.Circuits for local and global signal integration in primary visual cortexContrast-dependent changes in spatial summation and contextual modulation of primary visual cortex (V1) neuron responses to stimulation of their receptive field reveal long-distance integration of visual signals within V1, well beyond the classical receptive field (cRF) of single neurons. To identif...Primary Visual Cortex; Extrastriate Cortex; Feed-back Connections; Lateral Connections; SUrround Modulation; Macaque2002-10-01
14 Normann, Richard A.; Campbell, Patrick K.; Jones, Kelly E.; Huber, Robert J.; Horch, Kenneth W.Silicon-based, three-dimensional neural interface: manufacturing processes for an intracortical electrode arrayA method has been developed for the manufacture of a "three-dimensional" electrode array geometry for chronic intracortical stimulation. This silicon based array consists of a 4.2 x 4.2 x 0.12 mm thick monocrystalline substrate, from which project 100 conductive, silicon needles sharpened to facilit...Electric Stimulation; Electrodes, Implanted; Sensory Cortex; Intracortical Electrode Array1991
15 Gesteland, Raymond F.Simian virus 40-specific polypeptides in Ad2+ND4- infected cellsA comparison of the proteins synthesized in human cells at late times after infection with adenovirus (Ad2) and with the adeno-simian virus 40 (SV40) hybrid viruses revealed polypeptides of 30,000 and 92,000 molecular weight specific for the hybrid viruses Ad2+ND1 and Ad2+ND4, respectively. Cell-fre...Molecular Weight; Peptide Biosynthesis; RNA, Messenger; Viral Proteins1976
16 Varner, Michael W.; Clark, Edward B.; Fernando, Kumari L.; Mathews, V. JohnRobust estimation of fetal heart rate variability using Doppler ultrasound.This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algori...Prenatal Ultrasonography; Fetal Heart Rate; Blood Flow Velocity; Algorithms2003-08
17 Normann, Richard A.; Campbell, Patrick K.; Jones, Kelly E.100 electrode intracortical array: structural variabilityA technique has been developed for fabricating three dimensional "hair brush" electrode arrays from monocrystalline silicon blocks. Arrays consist of a square pattern of 100 penetrating electrodes, with 400 microns interelectrode spacing. Each electrode is 1.5mm in length and tapers from about 100 m...Microelectrode arrays; Stimulation; Micromachining1990
18 Normann, Richard A.; Horch, Kenneth W.; Cha, KichulMobility performance with a pixelized vision systemA visual prosthesis, based on electrical stimulation of the visual cortex, has been suggested as a means for partially restoring functional vision in the blind. The prosthesis would create a pixelized visual sense consisting of punctate spots of light (phosphenes). The present study investigated the...Visual Prosthesis; Mobility; Phosphene Simulator1992
19 Normann, Richard A.; Kolb, Helga; Lasater, Eric M.Signal integration at the pedicle of turtle cone photoreceptors: an anatomical and electrophysiological studyThe morphology of the axon which connects the cell body and pedicle of turtle cone photoreceptors was studied by light and electron microscopy. The axon which contains numerous synaptic vesicles, some endoplasmic reticulum, and a few cisternae is basically filled with cytoplasm. The length of the ax...Cone Photoreceptor, Voltage Clamp; Isolated Cells; Input Resistance; Cell Body-Pedicle Coupling1989
20 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
21 Normann, Richard A.; Shoham, ShyEncoding mechanisms for sensory neurons studied with a multielectrode array in the cat dorsal root ganglionRecent advances in microelectrode array technology now permit a direct examination of the way populations of sensory neurons encode information about a limb's position in space. To address this issue, we recorded nerve impulses from about 100 single units simultaneously in the L6 and L7 dorsal root ...Sensory; Encoding; Multielectrode; Dorsal Root Ganglion; Cutaneour; Muscle2004
22 Normann, Richard A.; Johansson,Torbjorn; Abbasi, Masoud; Huber, Robert J.Three-dimensional architecture for a parallel processing photosensing arrayA three-dimensional architecture for a photosensing array has been developed. This silicon based architecture consists of a 10 x 10 array of photosensors with 80 microns diameter, through chip interconnects to the back side of a 500 microns thick silicon wafer. Each photosensor consists of a 300 x 3...Retina; Optics; Silicon; Photosensing1992
23 Normann, Richard A.; Abbasi, Masoud; Johansson,TorbjornSilicon carbide enhanced thermomigrationThe widespread acceptance of thermomigration technology to produce through-chip interconnects has been impaired by (i) a random walk of the Si-Al liquid eutectic inclusion as it traverses the wafer, and (ii) a ?surface barrier? which allows thermomigration of only relatively large inclusions. In ...Silicon Dioxide; Thermometers; Transducers; Thermomigration Technology; Infrared Lamps1992
24 Normann, Richard A.; Maynard, Edwin M.Neural interface for a cortical vision prosthesisThe development of a cortically based vision prosthesis has been hampered by a lack of basic experiments on phosphene psychophysics. This basic research has been hampered by the lack of a means to safely stimulate large numbers of cortical neurons. Recently, a number of laboratories have developed a...Neuroprosthetics; Artificial Vision; Electrode Arrays; Multielectrode Recordings; Biocompatibility1999
25 Normann, Richard A.; Clark, Gregory A.; McDonnall, DanielSelective motor unit recruitment via intrafascicular multielectrode stimulationRecruitment of force via independent asynchronous firing of large numbers of motor units produces the grace and endurance of physiological motion. We have investigated the possibility of reproducing this physiological recruitment strategy by determining the selectivity of access to large numbers of ...Funtional Neuromuscular Stimulation; Microelectrode Array; Neuroprosthesis; Intrafascicular Multielectrode Stimulation; Cats2004
1 - 25 of 127