Biomechanics and Biotransport Commons^™

Role Of Angiotensin I And Ii On The Tissue Mechanics Of The Aortic Heart Valve Via Receptor Binding And Converting Enzymes, Josh Fahy

Biomedical Engineering Undergraduate Honors Theses

The renin-angiotensin system (RAS) plays a crucial role in the regulation of renal, cardiac, and vascular physiology. This system regulates in vivo blood pressure and fluid balance. As renal blood flow decreases, the kidneys convert prorenin into renin and secrete it into the circulatory system. Renin then converts angiotensinogen into angiotensin I (ang-I). The ang-I is then converted into angiotensin II (ang-II) by the angiotensin-converting enzyme (ACE). Ang-II, a vasoconstrictor, increases blood pressure by causing the blood vessels to narrow. Recent evidence suggests that RAS may be involved in the progression of valve disease, most notably, aortic stenosis.

The first …

Classifying And Predicting Walking Speed From Electroencephalography Data, Allen Rahrooh

Electronic Theses and Dissertations

Electroencephalography (EEG) non-invasively records electrocortical activity and can be used to understand how the brain functions to control movements and walking. Studies have shown that electrocortical dynamics are coupled with the gait cycle and change when walking at different speeds. Thus, EEG signals likely contain information regarding walking speed that could potentially be used to predict walking speed using just EEG signals recorded during walking. The purpose of this study was to determine whether walking speed could be predicted from EEG recorded as subjects walked on a treadmill with a range of speeds (0.5 m/s, 0.75 m/s, 1.0 m/s, 1.25 …

Volumetric Muscle Loss: The Role Of Physical Activity And Autologous Repair On Force Recovery And Signaling Pathways, Richard Perry

Graduate Theses and Dissertations

Volumetric muscle loss affects both military and civilian persons. The hallmark of this injury is incomplete muscle regeneration, excessive fibrosis, and chronic inflammatory signaling resulting in permanent functional loss. Since permanent functional loss drastically reduces quality of life, many studies have been conducted to improve force recovery. Current scientific literature considers a repair strategy of either devitalized scaffolds infused with growth factors or viable tissue plus activating factors to be the more promising interventions for optimal force recovery. PURPOSE The purpose of this study is to incorporate autologous repair and physical activity and observe the effects of muscle force recovery …

Design Of Microporous Membranes For The Development Of Brain-On-Chip Devices, Andre Figueroa Milla

Biomedical Engineering Undergraduate Honors Theses

Traumatic brain injuries (TBIs) are a major global health concern that have an economic impact of $60 billion in the United States in related costs annually. Developing drugs for TBI treatment is an approach that currently faces limitations involving the permeability of the blood-brain barrier (BBB). The BBB naturally limits molecules from reaching the brain as a protective mechanism against disease, acting as a barrier during drug delivery. Understanding the BBB mechanically and chemically following a TBI could potentially assist future studies to alleviate the symptoms and long-term effects of TBI by pharmaceuticals. The Mechanobiology and Soft Materials Laboratory (MSML) …

Conceptualization And Fabrication Of A Bioinspired Mobile Robot Actuated By Shape Memory Alloy Springs, Lietsel Richardson

Electronic Theses and Dissertations

This work is an experimental study and fabrication of design concepts to validate the feasibility of smart materials and their applications in bio-inspired robotics. Shape-Memory Alloy (SMA) springs are selected as the smart material actuators of interest to achieve locomotion in the proposed mobile robot. Based on a previous design of the robot, this work focuses on both implementing a new locomotion concept and reducing size and weight of the previous design, both using SMA based actuators. Objectives are met in consideration of the conceptual mechanics of circular robot locomotion. The first prototype is a variation of the original design. …

Fluctuations In Walking Speeds And Spatiotemporal Gait Parameters When Walking On A Self-Paced Treadmill At Level, Incline, And Decline Slopes, Cesar Castano

Electronic Theses and Dissertations

On a daily basis, humans walk over a variety of terrains. Studies have shown that spatiotemporal gait parameters, such as stride length, stride frequency, stride variability, etc., change when humans walk down a decline and up an incline compared to level ground. However, these studies have been limited to using fixed speed treadmills or analyzing a small number of strides when conducted over ground. Thus, there is a need to investigate the fluctuations in spatiotemporal gait parameters of humans walking at their self-selected speed, which requires recording hundreds of strides. Here we hypothesized that subjects will walk with a slower …

3d Printing A Microfluidic Chip Capable Of Droplet Emulsion Using Ninjaflex Filament, Robert Andrews

Mechanical Engineering Undergraduate Honors Theses

This paper details an investigation into methods and designs of 3D printing a microfluidic system capable of droplet emulsion using NinjaFlex filament. The specific field in which this paper’s experiment is rooted is dubbed “BioMEMS,” short for bio microelectromechanical systems. One prominent research area in BioMEMS is developing a “lab on a chip.” Essentially, the goal is to miniaturize common lab processes to the micro scale, rendering it possible to include these processes in a small chip. Reducing necessary sample sizes, shortening the reaction times of lab processes, and increasing mobility of lab processes can all be realized through microfluidic …

Role Of Local Renin-Angiotensin System In Potentiating Early Calcific Aortic Valve Disease, Jessica Perez

Graduate Theses and Dissertations

Angiotensin-II (Ang-II), a peptide hormone, is a potent vasoconstrictor and cell mitogen. It has been implicated in the development of hypertension as well as atherosclerosis. Recent work has shown that sclerotic aortic valves possess expression of angiotensin type I receptor (AT-1R) and angiotensin converting enzyme (ACE), suggesting altered angiotensin signaling during disease. The role of altered angiotensin signaling on aortic valve mechanics, however, is not clearly understood. We seek to understand the direct effects of the renin angiotensin signaling (RAS) system on the biological and biomechanical properties of aortic valve tissue and develop a finite constitutive model that mimics the …

Kinematics During Knee Extension, Lunge, And Chair Rise, Center For Orthopaedic Biomechanics, Kevin Shelburne, Phd, Michael D. Harris, Phd, Vasiliki Kefala, Donald R. Hume, Bradley S. Davidson, A. J. Cyr, R. H. Kim, A. A. Ali, E. M. Mannen

Living Kinematics of the Knee

No abstract provided.

The Effect Of Defects And Surface Modification On Biomolecular Assembly And Transport, Haneen Martinez

Nanoscience and Microsystems ETDs

Nanoscale transport using the kinesin-microtubule (MT) biomolecular system has been successfully used in a wide range of nanotechnological applications including self-assembly, nanofluidic transport, and biosensing. Most of these applications use the ‘gliding motility geometry’, in which surface-adhered kinesin motors attach and propel MT filaments across the surface, a process driven by ATP hydrolysis. It has been demonstrated that active assembly facilitated by these biomolecular motors results in complex, non-equilibrium nanostructures currently unattainable through conventional self-assembly methods. In particular, MTs functionalized with biotin assemble into rings and spools upon introduction of streptavidin and/or streptavidin-coated nanoparticles. Upon closer examination of these structures …

A Numerical Analysis Of The Effects Of Wing Kinematics On Flapping Wing Aeroacoustics, Kabilan Nedunchezian, Chang-Kwon Kang, Hikaru Aono

PRC-Affiliated Research

Despite the recent interest in flapping wing aerodynamics, the aerodynamic sound generation mechanism of a flapping wing is inadequately understood. In this paper, the interplay between the wing motion, resulting unsteady aerodynamics, and aeroacoustics of a flapping wing flyer is investigated. The wing motion is varied in terms of the flapping amplitude, pitching amplitude, and the phase difference between flap and pitch. The unsteady flow around the flapping wing is numerically calculated using a well-validated Navier-Stokes equation solver. Acoustic pressures are computed using the Ffowcs-Williams-Hawkings equation in a three-dimensional space at varying distances from the wing. Two main sound generation …

A Numerical Analysis Of The Effects Of Wing Kinematics On Flapping Wing Aeroacoustics, Kabilan Nedunchezian, Chang-Kwon Kang, Hikaru Aono

PRC-Affiliated Research

Despite the recent interest in flapping wing aerodynamics, the aerodynamic sound generation mechanism of a flapping wing is inadequately understood. In this paper, the interplay between the wing motion, resulting unsteady aerodynamics, and aeroacoustics of a flapping wing flyer is investigated. The wing motion is varied in terms of the flapping amplitude, pitching amplitude, and the phase difference between flap and pitch. The unsteady flow around the flapping wing is numerically calculated using a well-validated Navier-Stokes equation solver. Acoustic pressures are computed using the Ffowcs-Williams-Hawkings equation in a three-dimensional space at varying distances from the wing. Two main sound generation …

A Numerical Analysis Of The Effects Of Wing Kinematics On Flapping Wing Aeroacoustics, Kabilan Nedunchezian, Chang-Kwon Kang, Hikaru Aono

PRC-Affiliated Research

Despite the recent interest in flapping wing aerodynamics, the aerodynamic sound generation mechanism of a flapping wing is inadequately understood. In this paper, the interplay between the wing motion, resulting unsteady aerodynamics, and aeroacoustics of a flapping wing flyer is investigated. The wing motion is varied in terms of the flapping amplitude, pitching amplitude, and the phase difference between flap and pitch. The unsteady flow around the flapping wing is numerically calculated using a well-validated Navier-Stokes equation solver. Acoustic pressures are computed using the Ffowcs-Williams-Hawkings equation in a three-dimensional space at varying distances from the wing. Two main sound generation …

Gait Alterations After Anterior Cruciate Ligament Injury And Implications For Return-To-Play Testing, Lindsey Remski

UNO Student Research and Creative Activity Fair

Introduction: Reoccurring injury to the anterior cruciate ligament (ACL) is a major problem for individuals who undergo ACL reconstructive surgery despite them meeting current requirements for return-to-play. Previous studies have found alterations in gait kinetics and kinematics of ACL deficient and ACL reconstruction patients. It is unknown if gait parameters, such as peak joint angles and moments, provide different information about patient function from what is provided by return-to-play outcomes. Purpose: To assess the relationships between peak joint angles, peak joint moments, and return-to-play outcomes for individuals with ACL injury. Methods: 6 subjects (3 ACL reconstruction, 3 ACL deficient) performed …

Effects Of A Passive Dynamic Lower-Leg Exoskeleton During Walking, Blake Beier

UNO Student Research and Creative Activity Fair

The ankle joint is one of the most important joints during walking. If the muscles surrounding the ankle are weak, there are reductions in the ability to generate appropriate torques and powers at the ankle. This leads to slower self-selected walking speeds, which correlate with poor physical functioning, more disabilities, increased hospitalization visits and costs, and even mortality. Because of this, many orthotic and exoskeletal devices have been created to restore proper ankle function by promoting ankle plantar flexion. Utilizing 3D printing and an extension spring, we created an easily accessible, reproducible, and modifiable exoskeleton that has the potential to …

Intensity And Pattern Of Daily Physical Activity Of Claudicating Patients, Cody Anderson

UNO Student Research and Creative Activity Fair

file:///C:/Users/codya/Desktop/Cody%20et%20al_2019_Human%20Movement%20Variability%20Conference.pdf

Visual Contributions To Balance Control During Gait, Kyle Brozek

UNO Student Research and Creative Activity Fair

We propose to isolate the contributions of continuous OF to the orthogonal relationship between balance and gait control during treadmill walking using a series of conditions. Manipulating the direction of OF using a CAREN (Motek Medical, Amsterdam, Netherlands) virtual reality treadmill environment will isolate these visual contributions in human subjects as they walk. We plan to tease out the effect of OF direction on the relationship between gait and balance control by having healthy young adults perform a series of treadmill walking trials while immersed in a VR environment. This will be done by manipulating the direction of walking and …

Determining The Relationship Between Walking Activity And Inter-Day Patterns In Stroke Survivors, Sydney Andreasen

UNO Student Research and Creative Activity Fair

Populations that have suffered from stroke are generally less active than people of otherwise similar demographics and are more susceptible to further health problems, such as another stroke. This study seeks to assess the validity of a treatment that encourages stroke survivors to walk more steps each day, in order to improve their active abilities and become less idle by establishing motivation for activity and therefore, also establishing patterns in the distribution of that activity throughout a stroke survivor’s day. 172 subjects (6 months post-stroke) have participated in a step activity monitoring program to record steps taken using wearable pedometers. …

Gait Alterations In Peripheral Arterial Disease Are Not Worsened By The Presence Of Diabetes, Hafizur Rahman

UNO Student Research and Creative Activity Fair

Peripheral arterial disease (PAD) is a vascular disease where atherosclerotic blockages restrict blood flow to muscles in the lower extremities. Diabetes is a common co-morbid condition in PAD and has been shown to increase the risk of lower extremity amputation compared to PAD without diabetes. Although there is a clear pathological relationship between diabetes and PAD, the gait mechanics involved remain indistinct. Therefore, the purpose of this study was to determine whether the presence of diabetes in addition to PAD results in greater functional impairment during ambulation. Twenty-three subjects with PAD and twelve controls consented to participate in the research. …

Collision Work Performed By Patients With Peripheral Artery Disease, Alex Dzewaltowski, Sara A. Myers, Jason M. Johanning, Iraklis I. Pipinos

UNO Student Research and Creative Activity Fair

The goal of this study was to assess the differences in collision work performed by healthy, aged-matched controls compared to patients with peripheral artery disease (PAD) to provide foundations for an eventual exoskeleton design. Collision work is energy dissipated into the surrounding environment from impact, in this study’s case, upon heel strike. When designing an exoskeleton for patients with PAD, harvesting energy lost to collision work could be a valuable mechanism to improve walking performance. Devices designed to utilize the normally dissipated energy for assisting propulsion to improve walking performance are under-explored [1, 2]. The purpose of this study was …