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Full-Text Articles in Engineering

Rapid Prototyping To Roll-To-Roll Manufacturing Of Microfluidic Devices, Amber Lee Boutiette Dec 2019

Rapid Prototyping To Roll-To-Roll Manufacturing Of Microfluidic Devices, Amber Lee Boutiette

Electronic Theses and Dissertations

Microfluidics constitutes a widely applicable field of enabling technologies with great potential to revolutionize healthcare and biotechnology. The ability to miniaturize and parallelize processes with microfluidics is seen as a solution for many problems with diagnostics technologies and accessibility. Unfortunately, fabricating microfluidics often require extremely expensive, time consuming, and specialized high-precision methods, making both prototyping and commercial-scale mass manufacturing difficult to accomplish. In this work, we evaluate the feasibility of using a unique roll-to-roll (R2R) micropatterning manufacturing process coupled with Additive Manufacturing (3D printing) to rapidly prototype and produce microfluidic devices at high-volume on film or paper backings for applications …


Characterization Of Nano-Cellulose Based Composites For Biomedical Applications, Mitchell P. Chesley Aug 2019

Characterization Of Nano-Cellulose Based Composites For Biomedical Applications, Mitchell P. Chesley

Electronic Theses and Dissertations

The number of orthopedic surgeries performed globally has steadily increased over the past decade due to the standardization of procedures as well as technological advancements. During this time orthopedic devices have been composed predominantly of metals, such as Titanium, Vanadium, Molybdenum, and Stainless steel, as well as their alloys, due to the high strength and durability of these materials. However, metals may, in fact, be suboptimal for orthopedic devices. For example, metals exhibit Young’s modulus much greater than the surrounding bone, inducing localized stress-shielding promoting cortical atrophy, which can lead to osteoporosis. In recent years polymers have been successfully explored …


Design, Construction And Application Of A Home-Built, Two-Photon Microscope, William P. Breeding Aug 2019

Design, Construction And Application Of A Home-Built, Two-Photon Microscope, William P. Breeding

Electronic Theses and Dissertations

Two-photon microscopy (TPM) is a powerful, versatile imaging modality for the study of biological systems. This thesis overviews the relevant physics involved in TPM, design considerations and process of constructing a home-built, two-photon microscope, and provides a set of procedures to operate the system. Furthermore, this work explores several applications of TPM through the study of single-cell metabolism and imaging the cellular-material interface. Explored in particular depth was the imaging of cellulose nanofiber (CNF) materials, with the goal of understanding the three-dimensional nature of fibroblast cell growth when embedded within the materials. This work uncovered several optical properties of CNF, …


Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin Jul 2019

Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin

Electronic Theses and Dissertations

Mathematical modeling aims to provide a theoretical framework for understanding tissue dynamics and for establishing treatment response for diseased tissues, such as tumors. Previously published continuum models have successfully represented idealized two-dimensional and three-dimensional tissue for short periods of time. A recently published continuum model of cancer increases model complexity and describes three-dimensional tissue that, due to the required complexity of the geometric multigrid solver, can only be feasibly applied to millimeter-scale simulations. Furthermore, the computational cost for such models has hindered their application in the laboratory and in the clinic. With computational demands greatly outpacing current openMP-based approaches on …


Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii Jul 2019

Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii

Electronic Theses and Dissertations

Background: Left ventricular assist devices (LVAD) are operated at constant speeds (rpm), consequently, pump flow is passively determined by the pressure difference between the LV and aorta. Since the diastolic pressure gradient (~70 mmHg) is much larger than the systolic gradient (~10 mmHg), the majority of pump flow occurs during systole. This limitation results in sub-optimal LV volume unloading, LV washing, and diminished vascular pulsatility that may be associated with increased risk for clinically-significant adverse events, including stroke, bleeding, arteriovenous malformations, and aortic insufficiency. To address these clinical adverse events, an intelligent control strategy using pump speed modulation was developed …


3d Printed Bioinspired Vascularized Polymers, Kayla Marquis May 2019

3d Printed Bioinspired Vascularized Polymers, Kayla Marquis

Electronic Theses and Dissertations

Biological vascular systems contain a network of three-dimensional channels that transport and deliver necessary nutrients throughout the organism. These systems are complex, adaptable, and possess the ability to detect and respond to external stimuli as needed. In this work, we mimic the complexity and adaptability of biological systems by incorporating vascular systems into polymeric materials. Vacant channels are created using a fugitive ink technique along with 3D gel printing. Upon completion of vascular channel construction, proof of principle testing is performed by inoculating the polymeric surface with bacteria and adding antibiotics to the vascular channels. The system is then characterized …


Energy Expenditure And Stability During Self-Paced Walking On Different Slopes, Alanna Raffaelli May 2019

Energy Expenditure And Stability During Self-Paced Walking On Different Slopes, Alanna Raffaelli

Electronic Theses and Dissertations

Metabolic power and cost of transport (COT) are common quantifiers for effort when performing tasks including walking and running. Most studies focus on using a range of normal walking speeds over level ground or varied slopes. However, these studies use fixed-speed conditions. Fatigue, stability, metabolic expenditure, heart rate, and many other factors contribute to normal walking speed varying over time. This study aimed to show that allowing a subject to walk with a self-paced speed should correlate to a minimum COT at a given slope. This study also aimed to determine if a preferred slope exists based on minimizing metabolic …


Conceptualization And Fabrication Of A Bioinspired Mobile Robot Actuated By Shape Memory Alloy Springs, Lietsel Richardson May 2019

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 May 2019

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 …


Classifying And Predicting Walking Speed From Electroencephalography Data, Allen Rahrooh May 2019

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 …


Suture-Less Trocar Site Closure Clip, Hares A. Patel Apr 2019

Suture-Less Trocar Site Closure Clip, Hares A. Patel

Electronic Theses and Dissertations

Introduction: Following laparoscopic surgery, there is a need, in many cases, to close trocar sites to prevent hernias. Currently, devices that exist on the market are suture based, but the lack of standardization in the suturing techniques together with the time-consuming nature of the procedure leads to the need for improvement in trocar site closure products. Trocar closure sites do not need to be fully closed on the fascial layer; rather, sufficiently blocking the hole at the abdominal wall can significantly reduce post-operative herniation. A retrospective study on trocar site herniation (TSH) after laparoscopic surgery indicates a TSH incidence …


A Deep Learning Approach To Detect Diabetic Retinopathy In Fundus Images., Winston R. Furtado Apr 2019

A Deep Learning Approach To Detect Diabetic Retinopathy In Fundus Images., Winston R. Furtado

Electronic Theses and Dissertations

Background: Diabetic retinopathy is a disease caused due by complications of diabetes mellitus which can lead to blindness. About 33% of the US population with diabetes also show symptoms for diabetes retinopathy. If not treated, diabetic retinopathy worsens over time by progressing through two main pathological stages of non-proliferative and proliferative and four clinical stages. While the diagnostic accuracy of detecting diabetic retinopathy through machine learning have shown to be successful for OCT images, the accuracy of ultra-widefield fundus images have yet to be fully reported. This paper describes a method to non-invasively detect and diagnose diabetic retinopathy from ultra-widefield …


A Seed Dormancy Gene-Mediated Biotechnology To Mitigate Transgene Flow Into Weedy Rice, Luai Nahar Muhammad Jan 2019

A Seed Dormancy Gene-Mediated Biotechnology To Mitigate Transgene Flow Into Weedy Rice, Luai Nahar Muhammad

Electronic Theses and Dissertations

Transgene flows into wild/weedy relatives may cause ecological and economic problems. Seed dormancy is an adaptive trait that distributes germination over time and promotes persistence of weeds in agroecosystems. Silencing natural genes controlling seed dormancy (SD) could promote germination and reduce weed adaptability. The goal of this project was to develop a transgenic mitigation (TM) technology by linking to a primary transgene with an SD gene-silencing structure, as a tandem construct for transformation, to reduce the risk of gene flow into weed populations. In this research, the Bar (Bialaphos) gene for resistance to the glufosinate herbicide was used as a …


Modeling Runoff From Small Agricultural Watersheds In Eastern South Dakota, Bryce Siverling Jan 2019

Modeling Runoff From Small Agricultural Watersheds In Eastern South Dakota, Bryce Siverling

Electronic Theses and Dissertations

The capability to be able to consistently and accurately model any problem has potential time and money savings. The present study aimed to determine if the Natural Resources Conservation Service’s Curve Number (CN) model or the more detailed Soil and Water Assessment Tool (SWAT) Model can consistently and accurately model runoff events from small agricultural fields in Eastern South Dakota. The overall goal was to better understand models used to predict runoff and determine if they can produce accurate estimates of runoff from the watersheds being studied. Runoff measurements were collected from an agricultural field located south of Coleman, South …


The Relative Contribution Of Fixation Features, Activity, And Tibiofemoral Conformity On Initial Stability Of Cementless Tibial Trays, James Sullivan Deacy Jan 2019

The Relative Contribution Of Fixation Features, Activity, And Tibiofemoral Conformity On Initial Stability Of Cementless Tibial Trays, James Sullivan Deacy

Electronic Theses and Dissertations

Initial stability of cementless total knee replacements (TKR) is critical to implant success as excessive motion between the bone and implant prevents bony ingrowth that is critical to the long-term survivability of cementless implants. Prior studies have shown that excessive micromotion causes fibrous tissue growth instead of beneficial bony growth. There are many factors that influence initial stability including the design of the tibial tray and the tibiofemoral articulations. Understanding the impacts of these design features on micromotion between the bone and implants is crucial to improving the performance of cementless TKR. Prior studies only tested for the effect of …


Laxity Of The Hip Capsule In Natural And Posteriorly Implanted Specimens, Luke Storer Jan 2019

Laxity Of The Hip Capsule In Natural And Posteriorly Implanted Specimens, Luke Storer

Electronic Theses and Dissertations

The hip capsule consists of ligament tissue that surrounds the hip joint, providing stability to ensure proper alignment, prevent dislocation, and facilitate proper joint function. The objective of this study was to characterize the torque-rotation response of the natural and posteriorly implanted hip capsule in healthy cadaveric specimens in multiple degrees-of-freedom (DOF) and under combined loading scenarios using the AMTI VIVO, a robotic joint simulator. The anterior portion of the hip capsule was stained with Methylene Blue and virtual extensometers were calculated by Digital Image Correlation (DIC) software for Finite Element Analysis (FEA) model validation. The range of motion (ROM) …


Development Of An Impedance-Controlled Hot Snare Polypectomy Device To Minimize Tissue Damage, Curtislee Thornton Jan 2019

Development Of An Impedance-Controlled Hot Snare Polypectomy Device To Minimize Tissue Damage, Curtislee Thornton

Electronic Theses and Dissertations

This study explores the ability to measure the changing impedance, ex vivo, of a porcine colon sample while undergoing a high-frequency alternating current from an Olympus PSD-30 electrosurgical unit and stop the applied current before excessive tissue damage ensues. The causes of the thermal damage are first examined, followed by the construction and testing of the impedance-controlled feedback device. Perforation was observed to occur when the impedance of the tissue sample increased by 25% or more. Using this information, the device was tested for five power settings ranging from 10W-50W. In each trial, the feedback device stopped the applied current …