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26 Horch, Kenneth W.; Dhillon, Gurpreet S.Direct neural sensory feedback and control of a prosthetic 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...Peripheral Nerve Implant; Prosthetic Limb Control; Sensory Feedback2005-12
27 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
28 Gesteland, Raymond F.; Atkins, John F.; Ingram, Jennifer A.; Kelly, Paul J.; Grentzmann, GuidoDual-luciferase reporter system for studying recoding signalsA new reporter system has been developed for measuring translation coupling efficiency of recoding mechanisms such as frameshifting or readthrough. A recoding test sequence is cloned in between the renilla and firefly luciferase reporter genes and the two luciferase activities are subsequently measu...Amino Acid Sequence; Genes, Reporter; HIV; Antizyme; Translation1998
29 Normann, Richard A.Effects of GABA and related drugs on horizontal cells in the isolated turtle retinaThe role of GABA in the outer plexiform layer of the turtle retina has been examined by intracellular recordings from L- and C-type horizontal cells in the isolated retina preparation. GABA (1-5 mM) slightly depolarized the L-type horizontal cells, reduced the amplitude of their photoresponses, and ...Retina; Horizontal Cells; Synapse; Negative Feedback; GABA; Turtle1990
30 Christensen, Douglas A.Effects of increased energy prices on U.S. agriculture: an econometric approachAlthough the contents of this manuscript remain the responsibility of the authors, we wish to thanks a group of reviewers for the time and conscientious effort they put forth to solidify this final draft. Andrew Morton, Brian Holding, Wesley Buchele, and Arnold Paulsen deserve much credit for their ...Energy prices1981
31 Hendee, Shonn P.; Faour, Fouad A.; Christensen, Douglas A.; Patrick, Baharah; Durney, Carl H.; Blumenthal, Donald K.Effects of weak extremely low frequency magnetic fields on calcium/calmodulin interactions.Mechanisms by which weak electromagnetic fields may affect biological systems are of current interest because of their potential health effects. Lednev has proposed an ion parametric resonance hypothesis (Lednev, 1991, Bioelectromagnetics, 12:71-75), which predicts that when the ac, frequency of a c...Electromagnetic Fields; Calcium-binding Proteins; Lednev's Theory1996-06
32 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
33 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
34 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
35 Christensen, Douglas A.; Herron, James N.Evanescent coupling in a waveguide fluoroimmunosensorA key factor in the analysis of evanescently-coupled optical sensors, such as the planar waveguide immunosensor analyzed here, is the efficiency of coupling between the optical waveguide modes and the fluorescent sources located on the surface of the waveguide. This is an important parameter in dete...Evanescent coupling; Waveguide; Fluoroimmunosensor1992
36 Gesteland, Raymond F.; Atkins, John F.Evolutionary specialization of recoding: frameshifting in the expression of S. cerevisiae antizyme mRNA is via an atypical antizyme shift site but is still +1An autoregulatory translational shift to the +1 frame is required for the expression of ornithine decarboxylase antizyme from fungi to mammals. In most eukaryotes, including all vertebrates and a majority of the studied fungi/yeast, the site on antizyme mRNA where the shift occurs is UCC-UGA. The me...Antizyme; ODC; Polyamines; Frameshifting2006
37 Christensen, Douglas A.; Horch, Kenneth W.Experience with the first three years of an accelerated dual-degree program in biomedical engineeringOur Department of Bioengineering has instituted a pilot program aimed at helping a select group of highly qualified students obtain both bachelor's and master's degrees in an accelerated timeframe-approximately four years from the beginning of their university studies. A key element of this progra...Accelerated; Dual-degrees; Education2004
38 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
39 Christensen, Douglas A.FDTD modeling in the design of optical chemical sensor structuresThe finite-difference time-domain method (FDTD) is a numerical technique for solving Maxwell's equations in a discretized space and time frame. It has been used extensively in the analysis of electrically large structures in the microwave domain, but has only recently been applied to optical proble...Finite-difference time-domain method; Immunochemical fluorosensors; Planar waveguides1991
40 Christensen, Douglas A.; Vincent, G. MichaelFiberoptic laser angioplasty probe with optical steerabilityWe have designed and bench tested an optically steerable fiberoptic probe for use in laser angioplasty. The unique feature of this design is the use of a gradient-index (GRIN) lens attached to the distal end of a seven-fiber bundle. By selecting which fiber of the bundle is illuminated by the source...Fiberoptic probe; GRIN lens; Steerability1990
41 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
42 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
43 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
44 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
45 Horch, Kenneth W.Identification of single units in multi-unit recordings from peripheral nervesWe are developing a computer-based method for identifying individual action potentials in multi-unit peripheral nerve recordings. Threshold level, sinusoidal stimuli are used to elicit phase-locked activity from single units. These action potentials are digitized, and a template is constructed usin...Peripheral nerve; Neural recordings; Cutaneous mechanoreceptors1988
46 Christensen, Douglas A.; Andrade, Joseph D.Improved sensitivity in ellipsometry of thin biochemical films by employing sublayersEllipsometry is widely used for investigating the optical properties of thin films on planar substrates, including films of adsorbed proteins or polymers. The average thickness and effective refractive index of the adsorbed layer are calculated by measuring the A and ¥ ellipsometry parameters. Unfo...Biochemical films; SiO2 sublayer1990
47 Christensen, Douglas A.Influence of temperature probe sheathing materials during ultrasonic heatingThe influence of sheathing materials upon temperature probes used during the monitoring of ultrasonic heating was measured. The measurements show that the sheathing can be heated in a manner not representative of the temperature rise occurring in the surrounding material, altering the probe reading...Ultrasonic hyperthermia; Sheathing; Phantom tests; Teflon1986-05
48 Horch, Kenneth W.Information contrained in sensory nerve recordings made with intrafascicular electrodesMultiunit recordings were made in anesthetized cats with chronically implanted intrafascicular electrodes over a period of six months. Neural signals recorded with these electrodes consisted of activity in sensory fibers innervating a variety of cutaneous mechanoreceptors. Mechanical stimuli wer...Intrafascicular electrodes; Functional electrical stimulation (FES); Closed-loop control1991
49 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
50 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
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