Characterization of Gait Patterns in Common Gait Rehabilitation Exercises

Gait training is an important part of recovery from stroke or surgery, or treatment for neurological disorders such as Parkinson\u27s disease or Multiple Sclerosis. A gait monitor that uses infrared sensing technology has been developed at RIT and proven to successfully monitor an individual\u27s walking patterns over a variety of different terrain type

Mathematical modeling of nitric oxide transport mechanisms

Nitric oxide (NO) is a powerful vasodilator that plays an important role in normal physiological and pathophysiological conditions. The primary goal of this research was to advance the understanding of the interacting mechanisms between NO, O2, hemoglobin, blood flow, and multiple chemical species in the microcirculation under steady state and non-steady conditions. The general approach was to develop and validate a non-linear cylindrical diffusion-reaction mass transport model based on experimental data to analyze these factors. Different from prior studies in the literature, this study simulates the effects of multiple cylindrical vessel layers, coupled NO and O2 transport, O2-dependent production from different NOS isoforms, time-dependent transport and chemical reactions, convective transport, arteriole-venule pairing, dynamic changes in vessel diameter, and multiple chemical species including superoxide and peroxynitrite. In addition, numerous factors affecting NO and O2 availability such as viscosity, hematocrit, the Fähraeus effect, oxygen saturation, pH, and CO2 were modeled. Specific findings from this study suggest: that NO and O2 transport are fundamentally intertwined; that NO can help enhance O2 delivery to distal tissue regions, particularly at low PO2 values; that NO production from nNOS can help augment normal vasodilatory functions; that production of NO from iNOS and nNOS could act as a protective mechanism in pathological conditions; that the Fähraeus effect is significant in vessels less than 30 µm in diameter and leads to higher predicted NO concentrations; that arteriole-venule pairing acts to increase peak endothelial and tissue NO concentrations; that, due to differences in reaction times for different chemical species, non-steady state conditions should be included to capture any transient effects; convective transport significantly influences axial NO gradients and downstream vessel concentrations; and that, at even relatively low production rates, superoxide is a potent scavenger of NO. Overall, this study illustrates how mathematical modeling can be used as a powerful tool to understand interactive mechanisms affecting NO transport that often cannot be analyzed experimentally. This holds great promise for understanding disease processes associated with NO dysfunction and can assist in the development of novel treatment strategies or clinical therapeutics.Ph.D., Biomedical Engineering -- Drexel University, 200

Implementation of Soft-Lithography Techniques for Fabrication of Bio-Inspired Multi-Layer Dielectric Elastomer Actuators with Interdigitated Mechanically Compliant Electrodes

Advancements in software engineering have enabled the robotics industry to transition from the use of giant industrial robots to more friendly humanoid robots. Soft robotics is one of the key elements needed to advance the transition process by providing a safer way for robots to interact with the environment. Electroactive polymers (EAPs) are one of the best candidate materials for the next generation of soft robotic actuators and artificial muscles. Lightweight dielectric elastomer actuators (DEAs) provide optimal properties such as high elasticity, rapid response rates, mechanical robustness and compliance. However, for DEAs to become widely used as artificial muscles or soft actuators, there are current limitations, such as high actuation voltage requirements, control of actuation direction, and scaling, that need to be addressed. The authors’ approach to overcome the drawbacks of conventional DEAs is inspired by the natural skeletal muscles. Instead of fabricating a large DEA device, smaller sub-units can be fabricated and bundled together to form larger actuators, similar to the way myofibrils form myocytes in skeletal muscles. The current study presents a novel fabrication approach, utilizing soft lithography and other microfabrication techniques, to allow fabrication of multilayer stacked DEA structures, composed of hundreds of micro-sized DEA units

Relating PDEs in Cylindrical Coordinates and CTMCs with Levels of Concentration

We present the derivation of a CTMC with levels model of diusion in cylindrical coordinates from the partial dierential equation for Fick's law. The resulting model abstracts both molar concentration, by discrete levels, and spatial location, by discrete compartments. We apply the results to the diusion of nitric oxide in human vessels and illustrate with simulations in the PRISM tool

Practice Problems

Selected practice problems in the format of numerical problems, concept questions, and case studies are presented in this chapter. Each problem is labeled with an estimated level of difficulty and list of most relevant chapters. Solutions and hints for about half of these problems are provided in the following chapter