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76 Horch, Kenneth W.; Tuckett, Robert P.; Burgess, Paul RichardNeural signal for skin indentation depth. I. Changing indentationsPsychophysical tests on human subjects showed that judgments of skin indentation depth made when the fingertip was indented at rates from 0.2 to 16 mm/set were quite insensitive to changes in indentation velocity. Similar results were obtained on the forearm at indentation velocities of 0.4 to 16...Skin; Indentation; Nerve impulses1983
77 Christensen, Douglas A.General formulation for connecting sources and passive lumped-circuit elements across multiple 3-D FDTD cellsA previous extension of the finite-difference time-domain (FDTD) method to include lumped-circuit elements is further extended to model lumped-element circuits connected across multiple FDTD cells. This formulation is needed to model many kinds of circuits, like those with a transistor or other ac...Finite-difference time-domain method; Lumped-element circuit; Dielectric; Microstrip1996-02
78 Christensen, Douglas A.; Herron, James N.Optical immunoassay systems based upon evanescent wave interactionsImmunoassays based upon evanescent wave interactions are finding increased biosensing application. In these devices, the evanescent tail associated with total internal reflection of an incident beam at the substrate/solution interface provides sensitivity for surface-bound proteins over bulk molec...Diagnostics; Evanescence; Planar waveguides; Human chorionic gonadotropin (hCG)1996
79 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
80 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
81 Normann, Richard A.; Maynard, Edwin M.Neuronal interactions improve cortical population coding of movement directionInteractions among groups of neurons in primary motor cortex (MI) may convey information about motor behavior. We investigated the information carried by interactions in MI of macaque monkeys using a novel multielectrode array to record simultaneously from 12-16 neurons during an arm-reaching task. ...Motor Cortex; Monkey; Population Coding; Movement1999
82 Normann, Richard A.Effects of background illumination on the photoresponses of red and green cones1. The photoresponses of light- and dark-adapted red and green cone photoreceptors were recorded intracellularly in the retina of the turtle, Pseduemys scripta elegans. Background illumination produced similar effects on both types of cones. 2. In response to the onset of a prolonged, steady backgro...Turtles; Adaptation, Ocular; Retina; Signal Transmission1979
83 Horch, Kenneth W.; Tuckett, Robert P.; Burgess, Paul RichardNeural signal for skin indentation depth. II. Steady indentationsThe glabrous skin of the monkey's hand was stimulated with a waveform that indented the skin at a rate of 0.4 mm/set, held the skin steadily or nearly steadily indented for 12 set or longer, and then retracted back to the starting position. Recordings were made of activity in single afferent fibe...Skin; Indentation; Nerve impulses1983
84 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
85 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
86 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-degrees; Education2002
87 Christensen, Douglas A.Bringing an integrative modeling experience to a freshman biomedical engineering courseAs an integrating lab experience in our Fundamentals of Bioengineering freshman course, we have included a Major Project that ties together many of the principles of biomechanics and bioelectricity covered in the lecture. It uses the human systemic cardiovascular system as a model. During the first...Matlab2004
88 Christensen, Douglas A.Finite-difference time-domain modeling and experimental characterization of planar waveguide fluorescence sensorsThe finite-difference time-domain method (FDTD) is a powerful numerical technique for solving Maxwell's equations in a discretized space and time grid. Its applications have up to now been in the analysis of electrically large structures in the microwave domain, and the scope of investigations has b...Finite-difference time-domain method; Planar waveguide1992
89 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
90 Christensen, Douglas A.Interface of forest and agriculture in nonpoint pollution controlManagement practices of agriculture, including conservation and tillage options, recently have received a great deal of attention with respect to their impact upon the environment. Research efforts have focused both on the direct impacts of reduced on-site productivity resulting from the erosion of ...Suspended sediment; Channel erosion; Silviculture1983
91 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
92 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
93 Horch, Kenneth W.Information extraction from peripheral nervesThis work is directed toward providing better rehabilitation for people suffering from somatosensory loss and paralysis due to spinal cord injury, head trauma, or stroke. The goal of this project is to demonstrate that information suitable for controlling prosthetic devices, modulating functional el...Peripheral nerve; Neural recordings; Intrafascicular electrodes1991
94 Horch, Kenneth W.Electrical stimulation of the ventral lumbo-sacral spinal cord results in mixed recruitment order of quadriceps and tibialis anterior motor unitsPulse width modulated, twitch recruitment curves for quadriceps and tibialis anterior were obtained by stimulating their respective motor activation pools in the ventral lumbo-sacral portion of the spinal cord. The duration of the twitch responses were analyzed as a function of stimulus strength ...Quadriceps; Tibialis anterior; Ventral lumbo-sacral spinal cord; Reversed recruitment1997
95 Christensen, Douglas A.Extending the two-dimensional FDTD method to hybrid electromagnetic systems with active and passive lumped elementsThis paper extends the finite-difference time-domain (FDTD) method to include distributed electromagnetic systems with lumped elements (a hybrid system) and voltage and current sources. FDTD equations that include nonlinear elements like diodes and transistors are derived. Calculation of driving-p...Finite-difference time-domain method; Lumped elements1992-04
96 Christensen, Douglas A.Dispersion effects in fiber optic interferometryAn extended analysis of the effects of uncompensated fiber dispersion on the fringe visibility of a fiber optic interferometer is developed, with particular emphasis on stellar interferometry. Both material and waveguide dispersion for single-mode, polarization-preserving fibers are considered. It...Stellar interferometry; Fiber optics; Statistical optics1997
97 Christensen, Douglas A.Laser diode coherence length variation with drive current: a tool for dispersion measurementsA visible light (670nm) laser diode was used as a variable coherence length source to measure dispersion characteristics in single-mode fibers. The diode's spectral width, measured against increasing drive current, was found to change from about 16 nanometers to less than 0.2 nanometer. The corresp...Laser diode; Fiber interferometry1992
98 Gesteland, Raymond F.; Atkins, John F.Frameshifting in gene 10 of bacteriophage T7Gene 10 of bacteriophage T7, which encodes the most abundant capsid protein, has two products: a major product, 10A (36 kDa), and a minor product, 10B (41 kDa). 10B is produced by frameshifting into the -1 frame near the end of the 10A coding frame and is incorporated into the capsid. The frameshift...Frameshifting; Bacteriophage T7; RNA, Viral; Gene Expression1991
99 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
100 Christensen, Douglas A.Pulsed Schlieren system for visualizing beams from phased-array HIFU applicatorsWe have assembled a Schlieren system for imaging the beam patterns from HIFU transducers in water to verify the desired beam focusing and direction. It consists of a high power (65 mW) short-pulse (as short as 2 ns) laser emitting at 658 nm, a beam expander/spatial filter, water tank, 400 Jim round ...Ultrasound beam patterns; Pulsed laser; Wavefronts2007
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