UScholar Works
 
Filters: Department: "Bioengineering" Collection: "ir_uspace"
101 - 125 of 128
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CreatorTitleDescriptionSubjectDate
101 Horch, Kenneth W.Selective activation of muscle groups in the feline hindlimb thorough electrical microstimulation of the ventral lumbo-sacral spinal cordSelective activation of muscle groups in the feline hindlimb by electrical stimulation of the ventral lumbo-sacral spinal cord was investigated. Spinal cord segments L5 to S1 were mapped using a penetrating tungsten needle electrode. Locations that produced isolated contraction of quadriceps, ti...Functional electrical stimulation; Motor pools; Spinal chord stimulation2000
102 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
103 Horch, Kenneth W.Selective stimulation of peripheral nerve fibers using dual intrafascicular electrodesWe have studied activation of newe fibers by pairs of Pt-Ir wire electrodes implanted within single fascicles of the nerve innervating the gastrocnemius muscle in cats. The purpose of this study was to determine if these intrafascicular electrodes can activate nerve fibers in different fascicles...Functional electrical stimulation; Intrafascicular stimulation; Silicon electrode array1993
104 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
105 Horch, Kenneth W.Separation of action potentials in multiunit intrafascicular recordingsClassification of action potentials in multiunit recordings was based on the use of various types of features to uniquely characterize action potentials from different cells. We compared classification results obtained using three types of descriptive features: digitized data points, amplitude and ...Long-term implantable intrafascicular electrodes; Nerve recordings; Simulated neural data1992
106 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
107 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
108 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
109 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
110 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
111 Horch, Kenneth W.; Normann, Richard A.Simulation of a phosphene field based visual prosthesisA visual prosthesis for the blind based upon electrical stimulation of the visual cortex requires the development of an array of electrodes. To establish design specifications for such an electrode array, we have conducted psychophysical experiments with normally sighted subjects wearing a portable...Visual prosthesis; Phosphene simulator1990
112 Gesteland, Raymond F.; Atkins, John F.; Weiss, Robert B.Slippery runs, shifty stops, backward steps and forward hops: -2, -1, +1, +2, +5 and +6 Ribosomal frameshiftingFrameshift mutations frequently express residual levels of gene activity; that is, they are often leaky. This leakiness can be used as a tool to define the functional components that affect the reading frame during gene expression. Recent technological advances in the capability to efficiently bu...Molecular Sequence Data; Mutation; RNA, Transfer; Frameshifting1987
113 Horch, Kenneth W.Stability of chronic intrafascicular electrode recordingsWe have implanted intrafascicular electrodes in peripheral nerves of cats and have recorded neural activity from a small population of nerve fibers for as long as six months, suggesting that these electrodes can be used on a chronic basis to acquire information about limb position, muscle force and ...Intrafascicular electrodes; Electrode recordings1989
114 Normann, Richard A.Statistical encoding model for a primary motor cortical brain-computer interfaceA number of studies of the motor system suggest that the majority of primary motor cortical neurons represent simple movement-related kinematic and dynamic quantities in their time-varying activity patterns. An example of such an encoding relationship is the cosine tuning of firing rate with respect...Discrete Distribution; LN Model; Neural Decoding; Neuroprosthetics; Sequential Monte-Carlo Filter2005
115 Normann, Richard A.; Shah, Maulik R.Study of printed spiral coils for neuroprosthetic transcranial telemetry applicationsWe have explored the use of printed spiral coils (PSC's) for neuroprosthetic transcranial telemetry applications. We fabricated two-dimensional PSC's on a thin (25 microns) polyimide substrate using copper (35 microns) as a conducting material. All the coils had a fixed inner diameter of 1.0 cm. We ...Blindness; Neuroprosthesis; Transcranial Telemetry System; Prosthesis Design1998
116 Normann, Richard A.; Muller, Jay F.; Kolb, HelgaSynaptic inputs to physiologically defined turtle retinal ganglion cellsTwo physiologically distinct, HRP-marked turtle retinal ganglion cells were examined for their morphology, GABAergic, glycinergic, and bipolar cell synaptic inputs, using electron-microscopic autoradiography and postembedding immunocytochemistry. One cell was a color-opponent, transient ON/OFF gangl...Turtles; Neural Pathways; Synapes; Retinal Ganglion Cells1991
117 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
118 Horch, Kenneth W.Towards a neuroprosthetic armEvidence indicates that user acceptance of modern artificial limbs by amputees would be significantly enhanced by a system that provides appropriate, graded, distally referred sensations of touch and joint movement, and that the functionality of limb prostheses would be improved by a more natural co...Neuroprosthetic arm; Peripheral nerve; Neuroprosthetics; Amputee2006
119 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
120 Gesteland, Raymond F.Translation of Rl7 RNA fragmentsExamination of the events during infection of cells by RNA phages reveals phemonomena that are surprisingly complex for a virus that has only enough information to code for three to four proteins. The coat protein is synthesized at a rapid rate through most of the infectious cycle making it the pre...Electrophoresis; RNA, Messenger; Peptide Biosynthesis; Kinetics1969
121 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
122 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
123 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
124 Gesteland, Raymond F.; Atkins, John F.; Tuohy, Therese M.Uninterrupted translation through putative 12-nucleotide coding gap in sequence of carA: business as usualPrevious work of others reported an untranslated stretch of 12 nucleotides in the 5' coding sequence of carA from Pseudomonas aeruginosa. However, N-terminal protein sequencing of carA-lacZ translational fusions shows that these 12 nucleotides are normally translated in a continuous triplet manner, ...Base Sequence; Protein Biosynthesis; Sequence Deletion1994
125 Horch, Kenneth W.Unit analysis in composite neural recordingsWe have used threshold level, sinusoidal stimuli to selectively elicit phase-locked activity from cutaneous mechanoreceptors, for the purpose of evaluating single unit activity in multi-unit peripheral nerve recordings. Each receptor is characterized by its response to a range of mechanical stimuli ...Neural recordings; Nerve fibers; Cutaneous mechanoreceptors1989
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