Spatial summation of individual cones in human color vision.

The human retina contains three classes of cone photoreceptors each sensitive to different portions of the visual spectrum: long (L), medium (M) and short (S) wavelengths. Color information is computed by downstream neurons that compare relative activity across the three cone types. How cone signals are combined at a cellular scale has been more difficult to resolve. This is especially true near the fovea, where spectrally-opponent neurons in the parvocellular pathway draw excitatory input from a single cone and thus even the smallest stimulus projected through natural optics will engage multiple color-signaling neurons. We used an adaptive optics microstimulator to target individual and pairs of cones with light. Consistent with prior work, we found that color percepts elicited from individual cones were predicted by their spectral sensitivity, although there was considerable variability even between cones within the same spectral class. The appearance of spots targeted at two cones were predicted by an average of their individual activations. However, two cones of the same subclass elicited percepts that were systematically more saturated than predicted by an average. Together, these observations suggest both spectral opponency and prior experience influence the appearance of small spots

Transmission of Stereo Audio Signals with Lasers

An alternative method for transmitting audio signals via the use of laser technology was presented here. The primary focus of this document is on the audio amplifier subsystem including the design, simulation, and performance results. Simulations using the PSPICE computer simulation software were utilized to investigate the theoretical designs of the audio amplifier subsystem. The audio amplifier was examined in three junctures including the noise-canceling input stage, the high voltage gain cell, and the low impedance driver. Through the design procedure using theoretical calculations, simulations using PSPICE computer software, and examination of the finished product with an oscilloscope, the audio amplifier was greatly investigated and verified for desired functionality. In addition, the pulse-width modulation technique was examined and implemented with precision 555 timers in order to transmit audio signals via laser

Model Development and Assessment of the Gate Network in a High-Performance SiC Power Module

The main objective of this effort is to determine points of weakness in the gate network of a high-performance SiC power module and to offer remedies to these issues to increase the overall performance, robustness, and reliability of the technology. In order to accomplish this goal, a highly accurate model of the gate network is developed through three methods of parameter extraction: calculation, simulation, and measurement. A SPICE model of the gate network is developed to analyze four electrical issues in a high-speed, SiC-based power module including the necessary internal gate resistance for damping under-voltage and over-voltage transients, the disparity in switching loss between paralleled devices due to propagation delay, a high-frequency oscillatory behavior on gate voltage due to die-to-die interactions, and current equalization in the kelvin-source signal path. In addition, the analysis of parameter variance between paralleled MOSFETs and the effects of mismatched threshold voltage and on-state resistance on switching loss and junction temperature are investigated. Finally, three Miller Clamp topologies are simulated and assessed for effectiveness culminating in a solution for parasitic turn-on in high dv/dt systems such as those utilizing high-performance SiC power modules

CONNECTED AND AUTONOMOUS VEHICLES EFFECTS ON EMERGENCY RESPONSE TIMES

Emergency response times have been shown to be directly correlated with mortality rates of out-of-hospital patients. Studies have been conducted to show the relationship between time and mortality rates until patients receive the proper treatment. With more cardiac arrests and other life threatening illnesses occurring in the United States, more emergency calls will be required as well. As of today, technological advancements have been made to reduce response times, but human factors still require certain procedures, causing delays in the run time and increasing the rate of mortality. Here we show the results of emergency response times with the market penetration of connected and autonomous vehicles. With connected and autonomous vehicles, the average time emergency vehicles spend on the roadways can be significantly decreased. Safety procedures with human drivers can be eliminated, giving the emergency vehicle a proper right-of-way through virtual emergency lanes and removing the need to slow down and avoid vehicles at intersections or during periods of heavy congestion. Our results show a three minute decrease in response time under full market penetration of the technology, reducing the mortality rate and increasing the potential to save lives

Correlations Between Shoulder Rotational Motion, Strength Measures and Throwing Biomechanics in Collegiate Baseball Pitchers

Pitching involves high stresses to the arm that may alter soft tissue responsible for controlling biomechanics. It has been hypothesized that imbalances in strength and flexibility of the dominant shoulder lead to decreased performance and increased injury risk, but it is not fully known what specific pitching biomechanics are altered. There is a critical need to determine correlations between shoulder rotational strength, range of motion and pitching kinetics. Without such knowledge, identifying potential for injury from shoulder imbalances will likely remain difficult and invasive. The goal of this study was to determine correlations between shoulder rotational strength and range of motion and kinetics. Twelve collegiate pitchers participated in this IRB approved study. The clinical measures session tested shoulder rotational range of motion and strength and grip strength. The motion analysis session tested pitching biomechanics. Paired t-tests investigated differences in strength and range of motion between arms. Linear regression was performed to determine correlations between clinical measures, kinetics and pitch velocity. Regression learner neural networks were created to predict pitch velocity and elbow varus torque using clinical measures as inputs. The dominant arm had significantly higher external rotation and total range of motion than the nondominant arm. The nondominant arm normalized external rotation peak torque was significantly greater than the dominant arm at 0˚ external rotation. Correlations were found between elbow varus torque and isometric external/internal rotation ratio, and between shoulder posterior shear force and isokinetic eccentric external rotation/internal rotation ratios. Correlations to velocity included grip strength, concentric external rotation peak torque, isometric internal rotation peak torques, and isometric external rotation peak torques. The neural network accurately predicted velocity, with the standard deviation of the error equal to 2.29 (2.97%). These correlations associate two testing methods to identify injury risk. Increasing external/internal rotation ratios may decrease elbow varus torque and shoulder posterior shear force. Increasing external rotation, internal rotation, and grip strength may lead to velocity gains. Velocity can be predicted using clinical measures and a neural network

Electrical characterization of single-walled carbon nanotubes : leading toward electronic devices

This thesis presents research involving the electrical characterization of single-walled carbon nanotubes produced by the pulsed-laser vaporization technique. Carbon nanotubes were suspended in organic solvents and separated using ultrasonic excitation. The dispersed nanotubes were either physically deposited or spin-deposited onto electrode structures that were prefabricated using standard electron-beam lithography. Atomic force microscopy was used to locate and measure nanotubes that spanned across metal electrodes. Two-probe charge transport measurements were then made on these nanotube samples. The first sample exhibited current rectification, while many other carbon nanotubes were damaged by electrical breakdown. The effect of manipulating a nanotube at the electrode junction is also demonstrated. It was found that a potential barrier could be introduced, changing the I-V response of the nanotube device. Then, p-channel field-effect transistor behavior is shown for an individual single-walled carbon nanotube. Finally, an electrodeposition technique is presented for reducing the large contact resistance between a nanotube and the metal electrodes. This technique decreased the electrode-nanotube contact resistance by a factor of more than six, and maintained the semiconducting behavior of the nanotube. Energy band diagram models are used to try to explain some of the observed electronic properties

Further studies on the mode-of-action of the alpha hemolysin of Staphylococcus aureus role of the receptor in hemolysis.

Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1984 .A877. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.Sc.)--University of Windsor (Canada), 1984

Structural And Chemical Characterization Of The S-layer Of Lampropedia Hyalina

The S-layer of Lampropedia hyalina is made of two separate layers. The inner, perforate layer, is composed of a 32kD polypeptide arranged in p6 symmetry with a lattice spacing of 14.6nm. The outer, punctate layer, is composed of tubular units connected by fine linking arms centred on p3 symmetry axes, to created a layer with p6 symmetry and a lattice constant of 25.6nm. Incubation of cell envelopes with 3M urea dissolved the punctuate layer and released three polypeptides of 60kD, 66kD and 240kD. These polypeptides reassembled to form the native punctate layer when dialysed against buffer containing 10mM CaCl{dollar}\sb2{dollar} or 10mM SrCl{dollar}\sb2{dollar}. The urea soluble polypeptides were fractionated by hydroxylapatite column chromatography. The isolated 60kD polypeptide formed ring-like structures, while the isolated 240kD polypeptide was visualized in negative stain as long, slightly curved threads. Fractions containing both the 60kD and 240kD polypeptides also contained complete assemblies of the punctate layer. This suggests that the central tubular units are composed of the 60kD polypeptide, while the linking arms consist of the 240kD polypeptide. One other fraction (66kD) may mediate attachment of the punctate layer to the underlying perforate layer thus forming the whole complex S-layer from at least four distinct polypeptides