Life Sciences Commons^™

Freezing Of Gait: Mechanisms, Mechanics, And Management, Peter S. Myers

Arts & Sciences Electronic Theses and Dissertations

Parkinson disease (PD) is a neurodegenerative disease with multiple motor and non-motor symptoms, including postural instability, gait impairments, and cognitive deficits. More than 50% of individuals with PD experience a symptom called freezing of gait (FOG), described as a transient inability to take another step forward. Individuals with PD who experience FOG (freezers) have further postural, gait, and cognitive impairments compared to individuals with PD without FOG (non-freezers). While degeneration of the dopaminergic neurons in the substantia nigra is accepted as the primary etiology of the disease, research shows that the disease has a global impact on the brain, accounting …

Performance Impact Of Different Lower-Limb Setup Positions In The Backstroke Swimming Start, Gordon E. Barkwell

Electronic Thesis and Dissertation Repository

The performance impact of different knee extension angles in the setup position for a backstroke start was evaluated using an instrumented starting surface. Ten backstroke swimmers completed maximum-effort starts in each of two setup positions: one with the knees flexed, and one with the knees extended. The start handles and touchpad were instrumented with tri-axial force plates. Activity of major hip and knee extensors was measured using surface electromyography. Body position was recorded throughout the start using two high-speed cameras. There was no difference in time to 10 m between the two conditions, indicating there is likely no advantage in …

Motor Variability In Rowing, Maude Potvin-Gilbert

Electronic Thesis and Dissertation Repository

The aim of the study was to analyze the impact of environment, intensity and distance rowed on temporal variability of strokes and on knee angle variability. 11 participants rowed 2,000 m at high and low intensities on an ergometer and at high intensity in a single on-water. Data were collected at the beginning and at the end of each exercise. All the factors influenced significantly the temporal variability (respectively beta=-0.013 and p .007=; beta= 0.007 and p=.021; beta=0.06 and p=.028). The difference of visual information and the need of the rower to adapt to environmental factors might explain …

Does Restricting Anterior Movement Of The Knees During A Barbell Back Squat Alter Lower Extremity Biomechanics?, Lucy Hayward Koshewa

Theses and Dissertations

INTRODUCTION: The strength implications of the barbell back squat make it ideal for use in training programs, rehabilitation, and competition. Even though the back squat is an integral part of these programs, there are also concerns about injury risk due to improper biomechanics. Restricted squats (knees kept behind the toes) are noted to reduce joint loading at the knees but may not take into account added potential risks for the entire lower extremity. Unrestricted squats are more representative of natural movement patterns but may increase joint loading especially at the knees. Research has explored the biomechanics of back squats in …

Microenvironment Regulates Fusion Of Breast Cancer Cells, Peiran Zhu

Masters Theses

Fusion of cancer cells has been observed in tumors for more than a century and is thought to contribute to tumor development and drug resistance. The low frequency of cell fusion events and the instability of fused cells have hindered our ability to understand the molecular mechanisms that govern cell fusion. We have developed a patterned gel system that can isolate cell fusion events and we demonstrate that several breast cancer cell lines can fuse into multinucleated giant cells in vitro, and the initiation and longevity of fused cells can be regulated solely by biophysical factors. Dynamically tuning the adhesive …

Digging Biomechanics In Geomyoid Rodents, Alexis Moore Crisp

UNLV Theses, Dissertations, Professional Papers, and Capstones

Subterranean digging behaviors provide opportunities for protection, access to prey, and predator avoidance for a diverse array of vertebrates, yet studies of the biomechanics of burrowing have been limited by the technical challenges of measuring kinetics and kinematics of animals moving within a substrate. Prior studies of burrowing have recorded a single axis of x-ray video and/or force. However, empirical observations show that burrowing is not restricted to a single axis or plane. I describe a new system called a ‘tunnel-tube’ for measuring 3D reaction force during burrowing. This tunnel-tube has two separate tubes, one ‘entry tube’ that has no …

Multiscale Investigation Of The Behavior Of Heart Valve Interstitial Cells In Response To Pathological Shape And Mechanical Stimulation, Ngoc Thien Lam

Graduate Theses and Dissertations

Our works aim to provide an insight into how aortic valve interstitial cells (VICs) respond to pathological shape and mechanical stimulation as well as the potential signaling pathway that mediates these responses, using a multiscale approach. A single cell model was developed to investigate the effect of altered shape on valve cell function as valve cells were reported to significantly deform during the cardiac cycle. Single VICs were controlled to take on features with different width-to-length aspect ratios that corresponded to the steady-state shapes adopted by VICs when stretched to 0%, 10% and 20%, respectively. It appeared that single VIC …

The Impact Of Upc Placement On The Biomechanical Injury Risk Factors Associated With Cashier Work, Marcus Payne

Graduate Theses and Dissertations

The purpose of this study was to investigate the impact of UPC placement on upper-body kinematics and muscle activity associated with cashier work. Seventeen female participants who had worked at least 1000 hours as a cashier and did not meet any exclusion criteria were recruited. Multi-sided UPC items, which included extra and/or larger barcodes, were compared to items with a traditional UPC placement. Two mock carts of eighteen items were scanned for each UPC type. Electromyography was applied bilaterally to the biceps brachii, middle deltoid, flexor digitorum superficialis, and upper trapezius muscles. Cumulative and peak muscle activity were calculated for …

Electrical And Biomechanical Properties Of Rat Ventricular Myocytes: Effect Of Exercise-Training & Beta-Adrenergic Regulation, Xinrui Wang

Dissertations (1934 -)

Heart disease is one of the leading causes of morbidity and mortality in the western world, and programs of exercise-training have been shown to ameliorate cardiovascular risk factors and protect against heart diseases. The cellular/molecular mechanisms of regular exercise induced adaptations in the heart remains incomplete. To address this, female and male Sprague-Dawley rats were randomly assigned to exercise trained (TRN) or sedentary (SED) groups. After 6-8 weeks training, ventricular myocytes were isolated and studied.Exercise-training prolonged the action potential duration (APD) in myocytes isolated from apex and base regions at low stimulation rate (1Hz), while shortening the APD at high …

Real-Time Assessment And Visual Feedback For Patient Rehabilitation Using Inertial Sensors, Deepa Adinarayanan

ETD Archive

Rehabilitation exercises needs have been continuously increasing and have been projected to increase in future as well based on its demand for aging population, recovering from surgery, injury and illness and the living and working lifestyle of the people. This research aims to tackle one of the most critical issues faced by the exercise administers-Adherence or Non-Adherence to Home Exercise problems especially has been a significant issue resulting in extensive research on the psychological analysis of people involved. In this research, a solution is provided to increase the adherence of such programs through an automated real-time assessment with constant visual …

Muscle Activation Analysis With Kinematic Comparison Between Wind-Up And Stretch Pitching With Respect To The Upper And Lower Extremities, Megan M. Smidebush

Theses and Dissertations--Kinesiology and Health Promotion

Introduction: Baseball pitching is considered one of the most intense aspects within the game of baseball, as well as the most complicated dynamic throwing task in all of sports. The biomechanics of pitching have been heavily investigated in an attempt to identify optimal pitching mechanics in terms of pitching performance. Previous quantified upper body kinetics research has concluded that improved muscle strength is needed in attempting to achieve adequate upper body kinetics and efficient pitching performances. Therefore, it is the purpose of this research study to compare the lower extremity muscle and upper extremity muscle activation patterns and kinematic variables …

Predictive Modeling Of Hip Dislocation: Assessment Of Surgical And Patient Factors To Reduce The Occurrence Of Hip Instability And Adverse Clinical Outcomes, Daniel N. Huff

Electronic Theses and Dissertations

Instability and dislocation remain leading indications for revision of primary Total Hip Arthroplasty (THA). Many studies have addressed the links between implant design and propensity for dislocation, however a comprehensive review of the ability of modern THA constructs to protect against joint instability is needed.

Accordingly, the objective of this study is to provide objective data about THA risks to be considered in the treatment algorithm to protect against adverse joint loading conditions and joint instability. Adverse loading conditions were assessed in a population of activities of daily living using data from telemetric hip implant representation in an FE simulation …

The Biomechanical Impact Of Weight On The Lower Extremity, Amanda Lee Ransom

Theses and Dissertations--Kinesiology and Health Promotion

Background: Obesity is a chronic disease characterized by a body mass index (BM1) of ≥ 30 kg/m² which negatively impacts the musculoskeletal system and has been found to be a major contributing factor to obesity-induced biomechanical alterations during activities of daily living (ADLs). A certain level of mobility is required for all populations to maintain independence and a good quality of life becomes more difficult with excess weight. Using a reduced weight-bearing activity, such as the Alter Gravity treadmill, would be beneficial in an obese population to reduce the load on the joints and potentially decrease the risk of …

Production Of Synthetic Spider Silk, Ryan Matthew Hekman

University of the Pacific Theses and Dissertations

Spider silk is a material that both has impressive mechanical properties and is also environmentally friendly. Though there are limitless potential engineering applications for such materials, industrial production of spider silk has proven to be challenging. Farming silk from spiders, as is done with silkworms, is not a viable option for large-scale production of spider silk due to the venomous and predatory nature of spiders. Here, an attempt is made to express synthetic spider silk minifibroins heterologously in Escherichia coli, to purify the recombinant spidroins from cell lysate, and to spin them into artificial fibers through a biomimetic process. Silk …