Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 189

Full-Text Articles in Biomedical Engineering and Bioengineering

Validation Of Computational Methods For Fracture Assessment Of Metastatic Disease To The Proximal Femur, Palani Taver Permeswaran May 2018

Validation Of Computational Methods For Fracture Assessment Of Metastatic Disease To The Proximal Femur, Palani Taver Permeswaran

Theses and Dissertations

Stage IV cancer is characterized by a cancer’s ability to metastasize, or spread throughout the body. Metastatic disease in bone is a devastating condition affecting hundreds of thousands of people each year. Stage IV cancer patients suffering from metastatic disease in the proximal femur are at high risk of catastrophic pathologic fracture, an event which severely impacts patient health. Although metrics have been created to assess the risk of impending fracture, they lack specificity in the proximal femoral region. Shortcomings of these metrics further complicate clinical decision making related to prophylactic fixation in these medically compromised individuals.

Fortunately, by ...


2d And 3d Control Of Photopolymerized Polycaprolactone Scaffolds For Cell Replacement Therapy In Retinal Disease, Jessica Rae Thompson May 2018

2d And 3d Control Of Photopolymerized Polycaprolactone Scaffolds For Cell Replacement Therapy In Retinal Disease, Jessica Rae Thompson

Theses and Dissertations

Obstacles to the realization of polymer scaffolds to be used for cell replacement therapies often include the challenges in controlling the microstructure of biocompatible molecules in three dimensions at cellular scales. Two-photon polymerization (TPP) of acrylated poly(caprolactone) (PCL) offers a means of achieving precise microstructural control of a material in a biocompatible and biodegradable platform. Two obstacles inhibit the efficient development and research of this method: there is not a commercially available acrylated PCL and the fabrication time using TPP can be lengthy. Initially in this work, TPP parameters and molecular structures were varied to find the ideal relationship ...


Investigating The Effect Of Fluid Shear Stress On The Failure Of Cancer Cell Membranes: An Experimental And Computational Analysis, Leah M. Vandenbosch May 2018

Investigating The Effect Of Fluid Shear Stress On The Failure Of Cancer Cell Membranes: An Experimental And Computational Analysis, Leah M. Vandenbosch

Theses and Dissertations

Cancer metastasis, or the formation of a secondary tumor at a site distant from the primary tumor, is known to be an inefficient process. Historically, it was believed that the shear stresses and forces experienced by cancer cells traveling through the circulatory system are major limiting factors to their metastatic potential and viability. High levels of fluid shear stress are known to be capable of destroying tumor cells. However, more recent research has shown that cancer cells survive migration through the circulatory system and extravasation into distant tissues with a high degree of efficiency, indicating that hemodynamic forces are not ...


Multi-Parented End-Effectors In Optimization-Based Prediction Of Posture And Anthropometry, Anna Seydel Jan 2018

Multi-Parented End-Effectors In Optimization-Based Prediction Of Posture And Anthropometry, Anna Seydel

Honors Theses at the University of Iowa

Improving motion capture processing onto a virtual model is an important research area. Although there has been significant research in this field, little work has been done to determine posture and anthropometry simultaneously with the intent of visualizing the data on virtual models. Many existing techniques are less accurate when applying processed data to a virtual model for biomechanical analysis. This paper presents a novel approach that estimates posture and anthropometry using optimization-based posture prediction to determine joint angles and link-lengths of a virtual model. By including anthropometric design variables, this approach introduces flexible handling of innate variance in subject-model ...


Neuropsychological And Morphometric Correlates Of Decision Making With The Coin Flip Task, Ashten Sherman Jan 2018

Neuropsychological And Morphometric Correlates Of Decision Making With The Coin Flip Task, Ashten Sherman

Honors Theses at the University of Iowa

The purpose of this study was to determine how older adults perform on a decision- making task (referred to as the Coin Flip Task), and how this performance correlates with demographic, neuropsychological, and brain morphometry variables. The study of decision making ability among older adults is important for several reasons. First, older adults frequently make “weighty” decisions as they age, such as important financial and medical decisions. When less than optimal decisions are made, it is difficult for the older adult to recover from or fix that decision given their relatively limited longevity. Second, decision making ability emanates from a ...


Electrostatic Precipitator To Collect Large Quantities Of Particulate Matter, Chun Hoe Ong Dec 2017

Electrostatic Precipitator To Collect Large Quantities Of Particulate Matter, Chun Hoe Ong

Theses and Dissertations

Traditional aerosol samplers are limited in their abilities to collect large quantities of particulate matter due to their low flow rates, high pressure drops, and are noise intrusiveness. The goal of this study was to develop an alternate aerosol sampler using electrostatic precipitation technology that was safe and not noise intrusive to be deployed in homes. The O-Ion B-1000 was selected as the most suitable electrostatic precipitator (ESP) for achieving the goal of this study because of its affordability, the design of its collection electrode and its high flow rate. The collection efficiency of the ESP was assessed for three ...


Characterizing Occupational Instabilities Induced By A Four-Dof All-Terrain Vehicle Simulator, John Stuart Michael Dec 2017

Characterizing Occupational Instabilities Induced By A Four-Dof All-Terrain Vehicle Simulator, John Stuart Michael

Theses and Dissertations

All-terrain vehicles (ATVs) are used widely throughout the United States both for recreational activities, such as hunting and riding, and in occupational settings, such as agriculture. In both such activities, ATVs can pose a risk of injury and death resulting from a number of factors, including operator error, operating in an altered state, and misuse. In a study by Milosavlijevic et al. (2011), a survey of agricultural workers in New Zealand displayed that roughly 60% of workers who operated an ATV experienced a loss of control event. The same study showed that nearly 50% of those occurred while riding on ...


Nanoparticles: Nanoscale Systems For Medical Applications, David Allen Wadkins Dec 2017

Nanoparticles: Nanoscale Systems For Medical Applications, David Allen Wadkins

Theses and Dissertations

The goal of this project was to develop a series of nano platforms for single cell analysis and drug delivery. Nanoparticles are a promising option to improve our medical therapies by controlling biodistribution and pharmacokinetics of therapeutics. Nanosystems also offer significant opportunity to improve current imaging modalities. The systems developed during this thesis work can be foundations for developing advanced therapies for obesity and improving our fundamental understandings of single cell behavior.

The first of the two systems we attempt to create was a drug delivery system that could selectively target adipose tissue to deliver uncoupling agents and drive browning ...


A Computational Investigation Of Patient Factors Contributing To Contact Stress Abnormalities In The Dysplastic Hip Joint, Holly Dominique Thomas Dec 2017

A Computational Investigation Of Patient Factors Contributing To Contact Stress Abnormalities In The Dysplastic Hip Joint, Holly Dominique Thomas

Theses and Dissertations

Acetabular dysplasia, a deformity characterized by the presence of a shallow acetabulum inadequately covering the femoral head, alters force transfer through a joint, causing early-onset hip pain and degeneration. Dysplasia is often treated surgically with a periacetabular osteotomy (PAO), which permits multiplanar acetabular reorientation to stabilize the joint and alleviate pain. PAO alters joint mechanics, including contact stress, which can be assessed via computational methods.

This work sought to enhance a discrete element analysis (DEA) model for assessment of the dysplastic hip. The primary focus was on understanding how the gait parameters used to load a DEA model affect the ...


Mechanobiology Of Keratinocyte Aggregate Formation And Its Role In Wound Healing, Hoda Zarkoob Aug 2017

Mechanobiology Of Keratinocyte Aggregate Formation And Its Role In Wound Healing, Hoda Zarkoob

Theses and Dissertations

Wound healing is an intrinsic response to injury or disease that generally results in scarring. In skin, restoration of the barrier function after wounding is critically dependent on re-epithelialization. During re-epithelialization keratinocytes from the wound margin migrate over the wound bed, proliferate and re-differentiate to make an intact epidermis. Mechanical cues may play an important role in epidermal sheet formation and re-epithelization.

Here, polyacrylamide (PA) gels with tunable stiffness were used to study the potential contribution of mechanical properties of the wound bed in re-epithelialization. Live cell imaging and deformation tracking microscopy was performed on primary human keratinocytes maintained on ...


Study Of Multi-Axial Failure Properties Of Planar Biological Soft Tissues, Timothy Kwang-Joon Chung Aug 2017

Study Of Multi-Axial Failure Properties Of Planar Biological Soft Tissues, Timothy Kwang-Joon Chung

Theses and Dissertations

Rupture of abdominal aortic aneurysm (AAA) is a catastrophic event that leads to high mortality and morbidity in patients. The primary causes associated with aneurysm rupture remain poorly understood despite rigorous investigations. Reports have shown that AAA that went on to rupture or present ruptured had higher peak wall tension (stress resultant) than those that did not go on to rupture or present ruptured. Studies investigating the material strength of ruptured AAA and unruptured AAA revealed that the uniaxial failure strength in ruptured AAA is no different on average than unruptured AAA. However, it is poorly understood whether uniaxial failure ...


Maintenance And Modification Of Mesenchymal Stromal Cell Immunosuppressive Phenotype, Alex Joseph Brown Aug 2017

Maintenance And Modification Of Mesenchymal Stromal Cell Immunosuppressive Phenotype, Alex Joseph Brown

Theses and Dissertations

The purpose of this study was to identify conditioning strategies for mesenchymal stromal cells (MSC) which optimize cellular immunosuppressive potency. By identifying new treatment strategies and previously unidentified small molecules capable of stimulating MSC we hope to pave the way tailoring licensed MSC phenotypes to be used in a specific disease state, rather than a one size fits all package. We sought to determine how MSC act in response to a changing immune response or environmental condition. MSC are exquisitely sensitive to changes in their environmental conditions and we show that cellular transcriptome and secretome changes are conditionally responsive to ...


Mechanisms And Prevention Of Sudep In Dravet Syndrome, Yujaung Kim May 2017

Mechanisms And Prevention Of Sudep In Dravet Syndrome, Yujaung Kim

Theses and Dissertations

Sudden unexpected death in epilepsy (SUDEP) is the most common cause of death in chronic refractory epilepsy patients. Dravet Syndrome (DS) is an infantile-onset epilepsy with severe seizures commonly due to mutations of the sodium channel gene SCN1A. DS patients have a high risk of SUDEP, but the mechanisms of death are not well defined. The principal risk factor for SUDEP is a high frequency of seizures. The recent MORTality in Epilepsy Monitoring Unit Study (MORTEMUS) reported the largest series of SUDEP cases while in Epilepsy Monitoring Units (EMUs). Most cases occurred after a generalized seizure, and were associated with ...


Development Of A Computational Model To Study Instability And Scapular Notching In Reverse Shoulder Arthroplasty, Vijay Niels Permeswaran May 2017

Development Of A Computational Model To Study Instability And Scapular Notching In Reverse Shoulder Arthroplasty, Vijay Niels Permeswaran

Theses and Dissertations

Reverse shoulder arthroplasty (RSA) is a common treatment for individuals with arthritis of the glenohumeral joint in the presence of a massive rotator cuff tear. Though this procedure has been effective in restoring function to these individuals, it has also been associated with high early to mid-term complications, such as scapular notching and instability.

A finite element (FE) modeling approach has previously been used to study the range of motion an individual with RSA could adduct their arm the polyethylene liner impinged on the inferior scapular bone and the contact stress at the impingement site. This model was then validated ...


Anthropometric Shape Parameters In Obese Subjects: Implications For Obese Total Joint Arthroplasty Patients, Kevin James Simoens May 2017

Anthropometric Shape Parameters In Obese Subjects: Implications For Obese Total Joint Arthroplasty Patients, Kevin James Simoens

Theses and Dissertations

Obesity is a severe concern worldwide and its prevalence is expected to continue to increase. Linked to diabetes, kidney disease, heart disease, and high blood pressure among other things, obesity has been identified as the forthcoming, largest preventable cause of mortality. Osteoarthritis, surgical consequences, distribution of subcutaneous adipose tissue, and alteration of joint biomechanics have vast implications in total joint repair (TJR). Previous studies have linked obesity to increased forces through weight-bearing lower extremities, alterations in gait, and risk of implant failure. The objectives of this study were to (1) provide a tool to predict lower extremity dimensions and shape ...


The Effect Of Variations In The Strength And Type Of Spinal Muscles On The Stabilization Of The Lumbar Spine Via Follower Compressive Load Mechanism, Ino Song May 2017

The Effect Of Variations In The Strength And Type Of Spinal Muscles On The Stabilization Of The Lumbar Spine Via Follower Compressive Load Mechanism, Ino Song

Theses and Dissertations

The ligamentous human lumbar spine is considered as a long and slender column, which can be buckled when subjected to the axial compressive load even less than 100N. However, previous in vivo study showed that the compressive force acting on the spine predicted by intradiscal pressure was exceed 2600N. Meanwhile, recent experiments suggested that, when the compressive force is subjected to the lumbar spine along the spinal curvature (follower load), the lumbar spine may support up to a compressive force of 1200N without buckling while maintaining its flexibility. Since such a follower load is directed tangential to the curved column ...


Surgical Treatment For Cervical Myelopathy: The Effect On Spinal Cord Strain Using Magnetic Resonance Imaging And Finite Element Modeling, Kirsten Elizabeth Stoner May 2017

Surgical Treatment For Cervical Myelopathy: The Effect On Spinal Cord Strain Using Magnetic Resonance Imaging And Finite Element Modeling, Kirsten Elizabeth Stoner

Theses and Dissertations

Cervical myelopathy is the most common form of spinal cord injury in North America with roughly 19,000 new cases in the US every year. It results from chronic compression of the spinal cord by osteophytes, intervertebral disc herniation, and ossified ligaments. It commonly affects adults over the age of 50 years and causes upper extremity numbness, loss of hand dexterity, gait disturbances, and decreased proprioception. Recent studies imaging studies have shown this injury is highly dependent on the dynamic motion of the spine, often worsening in extreme flexion and extension. Surgical intervention is the accepted mode of treatment with ...


Evaluation Of Trauma Response To Agricultural Injuries, Amanda Rachel Swanton May 2017

Evaluation Of Trauma Response To Agricultural Injuries, Amanda Rachel Swanton

Theses and Dissertations

Agriculture is a hazardous industry with high rates of occupational industry. Due to a variety of occupation-related factors, farmers may also be at risk for delays in reaching trauma services. Though the state of Iowa has a comprehensive trauma system implemented to provide an efficient response to traumatic injuries, it is unknown how farmers fare in this system. The aims of this study were to determine if the use of emergency medical services (EMS), the occurrence of interfacility transfers, the time to definitive care in severely injured patients, and the length of prehospital intervals for those using EMS differs between ...


Vibratory Stimulation Of Thyroid Epithelial Mimics Hormonal Stimulation, Andrew P. Wagner May 2017

Vibratory Stimulation Of Thyroid Epithelial Mimics Hormonal Stimulation, Andrew P. Wagner

Theses and Dissertations

Human vocalization has always been considered in the context of communication. In recent years, mechanical forces have been shown to have a wide variety of effects on biological systems. Since the vocal cords produce measurable vibrations to the surrounding tissue, including the thyroid, I hypothesize that vocalization could mechanically stimulate thyroid epithelial cells.

The data presented in this dissertation highlight some of the important factors for thyroid hormone synthesis. I was able to show that mechanical stimulation provided from vocalization has a similar response as hormonal stimulation on the thyroid. I also demonstrated that this response is dependent on the ...


Objective Quantification Of Sensory Function Using A Battery Of Smartphone Applications, Kasra Zarei May 2017

Objective Quantification Of Sensory Function Using A Battery Of Smartphone Applications, Kasra Zarei

Theses and Dissertations

Sensory deficits represent a major global public health problem. According to the World Health Organization, vision impairment affects an estimated 300 million people worldwide, and hearing impairment affects an estimated 360 million people worldwide. Consistent clinical evaluations for all individuals with sensory deficits cannot be practically realized due to the rising costs of healthcare, capital and labor limitations, and inaccessibility to healthcare due to a multitude of factors including proximity. The high prevalence of visual and hearing deficits can be lessened through consistent, comprehensive, at-home testing which can allow a larger amount of the affected and at-risk populations to be ...


Radiographic Assessment Of Lung Anatomy, Physiology, And Disease In A Porcine Model Of Cystic Fibrosis And People With Cystic Fibrosis, Ryan J. Adam May 2017

Radiographic Assessment Of Lung Anatomy, Physiology, And Disease In A Porcine Model Of Cystic Fibrosis And People With Cystic Fibrosis, Ryan J. Adam

Theses and Dissertations

Despite affecting many organ systems, the leading cause of morbidity and mortality in the cystic fibrosis (CF) population is lung disease. For the current studies we investigated elements of CF lung disease in a porcine model of CF and in people with CF. Our primary analysis tool was chest computed tomography (CT).

To investigate early CF lung disease we examined three week old CF and non-CF pigs. We found three week old CF pigs to have large, irregular tracheal smooth muscle bundles, airways of reduced size, airways of irregular shape, and airways of abnormal distensibility.

Three week old CF pig ...


Machine Learning Improves Automated Cortical Surface Reconstruction In Human Mri Studies, David G. Ellis May 2017

Machine Learning Improves Automated Cortical Surface Reconstruction In Human Mri Studies, David G. Ellis

Theses and Dissertations

Analysis of surface models reconstructed from human MR images gives re- searchers the ability to quantify the shape and size of the cerebral cortex. Increasing the reliability of automatic reconstructions would increase the precision and, therefore, power of studies utilizing cortical surface models. We looked at four different workflows for reconstructing cortical surfaces:

1) BAW + LOGIMSOS- B;

2) FreeSurfer + LOGISMOS-B;

3) BAW + FreeSurfer + Machine Learning + LOGISMOS-B;

4) Standard FreeSurfer(Dale et al. 1999).

Workflows 1-3 were developed in this project. Workflow 1 utilized both BRAINSAutoWorkup(BAW)(Kim et al. 2015) and a surface reconstruction tool called LOGISMOS-B(Oguz et al ...


Network-Based Approaches To Studying Healthy And Disease Development, Long Gao May 2017

Network-Based Approaches To Studying Healthy And Disease Development, Long Gao

Theses and Dissertations

Network biology has proven to be powerful tool for representing and analyzing complex molecular networks. It has also been successfully applied to biological field helping understand various biological processes. However, our current knowledge about the dynamics of gene networks during disease progression is rather limited. On the other hand, network construction is a prerequisite of network analysis. When the number of samples is limited, state-of-art computational methods for network construction are not robust in terms of low statistical power. In addition, molecular networks have been used extensively to improve the inference accuracy of causal coding variants, but this potential has ...


Longitudinal Medical Imaging Approaches For Characterization Of Porcine Cancer Models, Emily Marie Hammond May 2017

Longitudinal Medical Imaging Approaches For Characterization Of Porcine Cancer Models, Emily Marie Hammond

Theses and Dissertations

Cancer is the second deadliest disease in the United States with an estimated 1.69 million new cases in 2017. Medical imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), are widely used in clinical medicine to detect, diagnose, plan treatment, and monitor tumors within the body. Advances in imaging research related to cancer assessment have largely relied on consented human patients, often including varied populations and treatments. Tumor bearing mouse models have been highly valued for basic science research, but imaging focused applications are limited by the translational ability of micro imaging systems. Pig models are ...


Multimodal Evaluation Of Local And Whole-Joint Cartilage Changes In An In Vivo Animal Model, David James Heckelsmiller May 2017

Multimodal Evaluation Of Local And Whole-Joint Cartilage Changes In An In Vivo Animal Model, David James Heckelsmiller

Theses and Dissertations

Osteoarthritis is a chronic, deleterious disease of the joints. It currently affects nearly 25 million Americans. Clinically, osteoarthritis presents as joint pain and verified by radiographic evidence of joint space narrowing. Unfortunately, symptomatic osteoarthritis describes the later stages of disease, at which point irreversible cartilage and bone damage has occurred. Cross-sectional imaging modalities offer the promise of visualizing early features of disease, enabling the development and evaluation of interventions to forestall or prevent degenerative change. Modalities of clinical interest include magnetic resonance imaging (MRI) and multi-detector computed tomography (MDCT).

The following work describes the efficacy of MRI-derived measures for the ...


Utilizing Tumor Exome Variation To Predict Cancer Treatment Outcomes, Michael Rendleman Jan 2017

Utilizing Tumor Exome Variation To Predict Cancer Treatment Outcomes, Michael Rendleman

Honors Theses at the University of Iowa

Cancer genomics, in the context of informing clinical decisions with tumor genotype, is a field characterized by high-dimensional data. Computational approaches for evaluating sets of features to be utilized in machine learning methods are essential for yielding accurate predictive and prognostic models. Additionally, the publicly-available results of the Broad Institute’s Firehose cancer genomics analysis pipeline presents a wealth of information that may be useful for cancer genotyping. Power analysis and classifier comparison are performed with the goal of evaluating a gene-based mutation significance feature set (MutSig) from Firehose. They reveal that while the MutSig features likely contain some prognostic ...


Enhanced Phagocytic Capacity Endows Chondrogenic Progenitor Cells With A Novel Scavenger Function Within Injured Cartilage, Cheng Zhou Dec 2016

Enhanced Phagocytic Capacity Endows Chondrogenic Progenitor Cells With A Novel Scavenger Function Within Injured Cartilage, Cheng Zhou

Theses and Dissertations

Articular cartilage underwent serious joint injuries seldom repair spontaneously and might progress to post-traumatic osteoarthritis. This is majorly because articular cartilage’s unique properties that lack blood and nerve supply intrinsically. This peculiar structure, in addition, generates an unfavorable environment for certain phagocytes (macrophages, monocytes, neutrophils, etc) to infiltrate to cartilage to scavenge debris from cartilage matrix and cell caused from joint injuries. Therefore, physiological and functional regeneration of damaged cartilage is urgently needed and several clinical techniques have been developed, including microfracture, autograft transplantation, autologous chondrocytes implantation.

We previously identified highly migratory cells emerged and repopulated in cartilage damaged ...


Variant-Curation And Database Instantiation (Variant-Cadi): An Integrated Software System For The Automation Of Collection, Annotation And Management Of Variations In Clinical Genetic Testing, Andrea Rae Hallier Dec 2016

Variant-Curation And Database Instantiation (Variant-Cadi): An Integrated Software System For The Automation Of Collection, Annotation And Management Of Variations In Clinical Genetic Testing, Andrea Rae Hallier

Theses and Dissertations

One of the tools a clinician has in disease diagnosis and treatment is genetic testing. To generate value in genetic testing, the link between genetic variants and disease must be discovered, documented, and shared within the community. Working with two existing genomic variation tools, Kafeen and Cordova, a new set of features referred to as Variant-Curation and Database Instantiation (Variant-CADI) was identified, designed, implemented and integrated into the existing Cordova system to unite data collection, management and distribution into one cohesive tool accessible through user interfaces. This eliminates the user needing specialized knowledge of the underlying implementation, data pipeline or ...


Development Of Metrics To Describe Cerebral Aneurysm Morphology, Benjamin Micah Berkowitz Dec 2016

Development Of Metrics To Describe Cerebral Aneurysm Morphology, Benjamin Micah Berkowitz

Theses and Dissertations

Cerebral aneurysm is a pathology of the circulatory system in the brain in which an arterial wall balloons into a blood-filled sac. If the aneurysm ruptures, stroke can occur and has a high probability of causing permanent disability or death. Aneurysm surgery carries a high rate of morbidity and mortality compared to the natural rate of aneurysm rupture, so physicians must take care in recommending surgery for an aneurysm patient. However, very little is known about the etiology of brain aneurysm rupture and what prognostics exist. The International Study for Intracranial Aneurysms suggested that large aneurysm size and posterior location ...


Analysis Of Hindfoot Alignment For Total Ankle Arthroplasties, Heidi Kirsten Johanna Bingenheimer Dec 2016

Analysis Of Hindfoot Alignment For Total Ankle Arthroplasties, Heidi Kirsten Johanna Bingenheimer

Theses and Dissertations

Total ankle arthroplasties (TAAs) are mechanical devices used to replace the articular surfaces of the ankle joint in order to relieve pain for patients with osteoarthritis. Since most osteoarthritis is post-traumatic, and due to the highly variable individual foot geometry, TAAs are rarely inserted into normal geometry. This leads to serious problems with stresses and contact pressures in TAA components. This study uses finite element (FE) modeling to determine how hindfoot alignment, or how far in varus or valgus the most distal part of the calcaneus is perpendicularly from the axis of the tibia, affects the stresses and contact pressures ...