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Full-Text Articles in Biomedical Engineering and Bioengineering

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 ...


Computational Modeling Of Transcatheter Aortic Valves, Mostafa Abbasi Jan 2018

Computational Modeling Of Transcatheter Aortic Valves, Mostafa Abbasi

Electronic Theses and Dissertations

Transcatheter aortic valve replacement (TAVR) is an established therapy alternative to surgical valve replacement in high-risk and intermediate-risk patients with severe aortic stenosis. Currently, although TAVR is an alternative and less-invasive treatment for high-risk and intermediate-risk patients, surgical aortic valves replacement (SAVR) was still considered as the gold standard for low-risk patients. TAVR could potentially be applied to lower-risk younger patients if the indications can be safely expanded to the patients and transcatheter aortic valve (TAV) long-term durability can match with that of surgical bioprostheses. In contrast to surgical aortic valves (SAVs), there have been limited clinical data on the ...


Development Of Low Frequency Electron Paramagnetic Resonance Methods And Instrumentation For Biological Applications, Laura A. Buchanan Jan 2018

Development Of Low Frequency Electron Paramagnetic Resonance Methods And Instrumentation For Biological Applications, Laura A. Buchanan

Electronic Theses and Dissertations

EPR is a powerful biophysical tool that can be used to measure tumor physiology. With the addition of magnetic field gradients, the spectral properties of paramagnetic species can be mapped. To facilitate EPR imaging, methods and instrumentation at frequencies between 250 MHz and 1 GHz were developed.

At low spin concentrations, the rapid scan background signal is often many times larger than the EPR signal of interest. To help remove the background contribution, a data acquisition procedure that takes advantage of a cross-loop resonator and bipolar power supplies was developed at 250 MHz. In this procedure, two scans are collected ...


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 Jan 2018

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 ...


Cementless Tibial Base Micromotion During Activities Of Daily Living, Hayden Wilson Jan 2018

Cementless Tibial Base Micromotion During Activities Of Daily Living, Hayden Wilson

Electronic Theses and Dissertations

Initial stability of cementless total knee replacement (TKR) components is directly related to long-term fixation and success, as excess motion hinders bony ingrowth. To assess implant stability, there is a need for more physiologically accurate loading conditions, incorporating forces and displacements in all 6 degrees-of-freedom found in the knee joint, as well as understanding the impact of femoral flexion on conformity of tibiofemoral articulation. Understanding how different activities of daily living generate tibial micromotion yields insight into surgical technique considerations, and rehabilitation strategies post-operatively. ASTM F3141-15, which specifies knee flexion, Internal-External moment, Medial-Lateral, Anterior-Posterior and Superior-Inferior forces during gait and ...


Computer-Aided Cancer Diagnosis And Grading Via Sparse Directional Image Representations, Hadi Rezaeilouyeh Jan 2017

Computer-Aided Cancer Diagnosis And Grading Via Sparse Directional Image Representations, Hadi Rezaeilouyeh

Electronic Theses and Dissertations

Prostate cancer and breast cancer are the second cause of death among cancers in males and females, respectively. If not diagnosed, prostate and breast cancers can spread and metastasize to other organs and bones and make it impossible for treatment. Hence, early diagnosis of cancer is vital for patient survival. Histopathological evaluation of the tissue is used for cancer diagnosis. The tissue is taken during biopsies and stained using hematoxylin and eosin (H&E) stain. Then a pathologist looks for abnormal changes in the tissue to diagnose and grade the cancer. This process can be time-consuming and subjective. A reliable ...


Six Degrees Of Freedom Kinematics Of The Healthy Ankle Syndesmosis Joint, Veronica A. Hogg-Cornejo Jan 2017

Six Degrees Of Freedom Kinematics Of The Healthy Ankle Syndesmosis Joint, Veronica A. Hogg-Cornejo

Electronic Theses and Dissertations

Syndesmotic injury, more commonly known as a "high ankle sprain", accounts for over 12% of all ankle sprain incidents in the US; of which, over 25% occur during a sporting activity. Typically, harm to the syndesmosis occurs in sports such as football, soccer, lacrosse, and hockey where it is common for an athlete to experience rapid and extreme dorsiflexion-external rotations of the foot. Severe syndesmotic sprains have been noted by clinicians as the most difficult ankle injury to accurately diagnose and treat, require the most recuperation time, and often results in life-long dysfunction. Even more problematic, 40% of patients suffering ...


3d Bioprinting Hydrogel For Tissue Engineering An Ascending Aortic Scaffold, Benjamin Stewart Jan 2017

3d Bioprinting Hydrogel For Tissue Engineering An Ascending Aortic Scaffold, Benjamin Stewart

Electronic Theses and Dissertations

The gold standard in 2016 for thoracic aortic grafts is Dacron®, polyethylene terephthalate, due to the durability over time, the low immune response elicited and the propensity for endothelialization of the graft lumen over time. These synthetic grafts provide reliable materials that show remarkable long term patency. Despite the acceptable performance of Dacron® grafts, it is noted that autographs still outperform other types of vascular grafts when available due to recognition of the host's cells and adaptive mechanical properties of a living graft. 3-D bioprinting patient-specific scaffolds for tissue engineering (TE) brings the benefits of non-degrading synthetic grafts and ...


Segmental Movement Compensations In Patients With Transtibial Amputation Identified Using Angular Momentum Separation, Brecca M. M. Gaffney Jan 2017

Segmental Movement Compensations In Patients With Transtibial Amputation Identified Using Angular Momentum Separation, Brecca M. M. Gaffney

Electronic Theses and Dissertations

Patients with unilateral dysvascular transtibial amputation (TTA) adopt movement compensations that are required to maintain balance and achieve ambulation in the absence of ankle plantar flexion, and result in increased and asymmetric joint loading patterns. As a result, this population is at an increased risk of overuse injuries, such as low back pain (LBP). Clinical gait analysis is used to guide diagnostics in movement retraining following amputation, and is performed using instrumented (research based) or observational analyses (clinically based). However, instrumented analyses are currently impractical in most clinical settings due to expense and computational limitations. This dissertation presents the use ...


Statistical Shape Modeling To Quantify Variation In The Proximal Humeral Anatomy, Paul B. Sade Sr. Jan 2017

Statistical Shape Modeling To Quantify Variation In The Proximal Humeral Anatomy, Paul B. Sade Sr.

Electronic Theses and Dissertations

The fit of the humeral prosthesis to the intramedullary canal and the replication of the anatomic humeral head center are important factors in Total Shoulder Arthroplasty (TSA). The objective of this thesis was to develop a Statistical Shape Model (SSM) of the cortical and cancellous bone regions of the proximal humerus, and to assess potential shape differences with gender and ethnicity, with a goal of informing implant design. An SSM was used and Principal Component Analysis (PCA) was applied to data that represented both the cancellous and cortical humeral bone of 63 healthy subjects and cadavers. Anatomical measurements and PC ...


Specimen-Specific Natural, Pathological, And Implanted Knee Mechanics Using Finite Element Modeling, Azhar Akber Ali Jan 2017

Specimen-Specific Natural, Pathological, And Implanted Knee Mechanics Using Finite Element Modeling, Azhar Akber Ali

Electronic Theses and Dissertations

There is an increasing incidence of knee pain and injury among the population, and increasing demand for higher knee function in total knee replacement designs. As a result, clinicians and implant manufacturers are interested in improving patient outcomes, and evaluation of knee mechanics is essential for better diagnosis and repair of knee pathologies. Common knee pathologies include osteoarthritis (degradation of the articulating surfaces), patellofemoral pain, and cruciate ligament injury and/or rupture. The complex behavior of knee motion presents unique challenges in the diagnosis of knee pathology and restoration of healthy knee function. Quantifying knee mechanics is essential for developing ...


Mechanical Effects Of Surgical Adhesives On Ascending Thoracic Aortic Aneurysm Replacement, Dong Qiu Jan 2017

Mechanical Effects Of Surgical Adhesives On Ascending Thoracic Aortic Aneurysm Replacement, Dong Qiu

Electronic Theses and Dissertations

Ascending thoracic aortic aneurysm (aTAA) is a potentially lethal disease which grows gradually over time and may lead to aortic dissection and rupture. Currently, aTAA surgical repair using Dacron graft is a well-established treatment. In addition, surgical adhesives are frequently used in the surgeries to seal the anastomotic site. This study aims to investigate mechanical effects of four commonly used surgical adhesives, namely BioGlue, CoSeal, Crosseal, and Tisseel, on the suture site using in-vitro digital image correlation (DIC) method and finite element (FE) simulations in an ovine model. In this study, first, mechanical properties of ovine ascending aorta were obtained ...


Statistical Shape And Intensity Modeling Of The Shoulder, Irene Sintini Jan 2017

Statistical Shape And Intensity Modeling Of The Shoulder, Irene Sintini

Electronic Theses and Dissertations

Anatomical variability in the shoulder is inherently present and can influence healthy and pathologic biomechanics and ultimately clinical decision-making. Characterizing variation in bony morphology and material properties in the population can support treatment and specifically the design, via shape and sizing, of shoulder implants. Total Shoulder Arthroplasty (TSA) is the treatment of choice for glenohumeral osteoarthritis as well as bone fracture. Complications and poor outcomes in TSA are generally influenced by the inability of the implant to replicate the natural joint biomechanics and by the bone quality around the fixation features. For this reason, knowledge of bony morphology and mechanical ...


Cost-Effective Prosthetic Hand Controlled By Emg, Mohammad Yahya Almuhanna Jan 2016

Cost-Effective Prosthetic Hand Controlled By Emg, Mohammad Yahya Almuhanna

Electronic Theses and Dissertations

A cost-effective five-finger prosthetic hand is designed from aluminum, modeled and controlled using surface Electromyography (EMG) signals, which are obtained from the human body. Force sensors are used to control required forces needed to grasp and pick objects. A prototype hand is developed and it is experimentally tested to reproduce a wide spectrum of human hand motions. The size of the five-finger hand is similar to an adult male human hand, and it is capable of reproducing most of movements. Each finger has the same number of links as the real/human hand. Each finger also has a force sensor ...


Regional Mechanical Properties And Microstructure Of Ovine Heart Chambers, Shahnaz Javani Jan 2016

Regional Mechanical Properties And Microstructure Of Ovine Heart Chambers, Shahnaz Javani

Electronic Theses and Dissertations

Mechanical properties of cardiac tissue play an important role in the normal heart function. As a baseline for understanding of physiology and pathophysiology of the heart, and for development and validation of new therapies, it is crucial to first understand the mechanical behavior of the normal heart tissue. Although heart chambers have the same embryonic origin, differences in the development of mechanical properties are expected to manifest over time during the adulthood period. Therefore, the goal of this study was to determine the passive mechanical properties of all heart chambers through a paired comparison study in an ovine model. Ovine ...


Ultra-Wideband Radar Based Human Motion Analysis, Zhichong Zhou Jan 2016

Ultra-Wideband Radar Based Human Motion Analysis, Zhichong Zhou

Electronic Theses and Dissertations

This thesis proposes and investigates two techniques in ultra-wideband (UWB) radar based human motion analysis. The first one is accurate human body landmark detection using UWB radars. The detection is achieved by moving target indication (MTI) and constant false alarm rate detection (CFAR). A new CFAR detection technique is proposed, namely the out-of-band (OB) CFAR detection. In the field experiment, two RF reflective markers are attached to the wrist and elbow of one human arm for reflecting radar signals. It is demonstrated that detection of two markers are feasible and successfully achieved. And our results suggests the OB-CFAR performs better ...


Multiscale Musculoskeletal Modeling Of The Lower Limb To Perform Personalized Simulations Of Movement, Alessandro Navacchia Jan 2016

Multiscale Musculoskeletal Modeling Of The Lower Limb To Perform Personalized Simulations Of Movement, Alessandro Navacchia

Electronic Theses and Dissertations

Computational modeling has been used for many decades to inform design and decision-making in several fields of engineering, such as aerospace, automotive, petroleum, and others. However, it still struggles to have a similar impact in fields of medicine, such as orthopaedics. Three of the challenges that have limited the use of computational modeling in the clinical practice and in product development are model validation, personalization, and realism. Validation is a challenge because several internal parameters of the human body, such as muscle forces, are not safely measurable in vivo and, consequently, a thorough comparison between model outputs and experimental measurements ...


Anatomy, Implant Selection And Placement Influence Spine Mechanics Associated With Total Disc Replacement, Justin F.M. Hollenbeck Jan 2016

Anatomy, Implant Selection And Placement Influence Spine Mechanics Associated With Total Disc Replacement, Justin F.M. Hollenbeck

Electronic Theses and Dissertations

Through aging and injury, the intervertebral disc of the lumbar spine can undergo degeneration, leading to collapse of the vertebrae and low back pain, a symptom that affects half the adult population in any given year. In an effort to reduce low back pain, total disc replacement treatment removes the degenerated disc, restores natural height and lordosis of the segment, and preserves motion at the joint. Patient anatomy, implant selection, and implant placement play significant roles in a patient's outcomes after total disc replacement surgery. Thus, the objective of the work presented in this thesis was to develop a ...


Finite Element And Probabilistic Analysis Of Soft Tissue Structures Of The Human Lumbar Spine, Dana Joseph Coombs Jan 2016

Finite Element And Probabilistic Analysis Of Soft Tissue Structures Of The Human Lumbar Spine, Dana Joseph Coombs

Electronic Theses and Dissertations

Human lumbar spine mechanics are influenced by soft tissue structures. Understanding and properly modeling these structures can help determine pathology, treatment, and implant design and performance. Finite element models of the L4-L5 level of the lumbar spine are often used, which include a representation of the intervertebral disc and spinal ligaments. Validation of these models are typically based on torque rotation data from a single subject or the models use average properties reported in literature. However, experimental testing reports variation up to 40% in ligament stiffness and even greater variability for annulus fibrosis properties. Probabilistic approaches enable consideration of the ...


Ex-Vivo Slaughterhouse Porcine Crystalloid-Perfused Beating Heart Via Langendorff Method, Rahiemin Talukder Jan 2016

Ex-Vivo Slaughterhouse Porcine Crystalloid-Perfused Beating Heart Via Langendorff Method, Rahiemin Talukder

Electronic Theses and Dissertations

The objective of this study was to resuscitate isolated beating porcine hearts obtained from slaughterhouse swine for a minimum of 1 hour with a crystalloid buffer reperfusion instead of blood via an extracorporeal Langendorff apparatus. The isolated beating heart functions outside of the body under simulated physiologic conditions. Live functional anatomy was controlled under benchtop experimental settings. Porcine hearts (26 total) were topically cooled with saline. 300mL of 25°C cardioplegia with 20KU Streptokinase was preflushed via aortic root. WIT was less than 5 minutes. 1L 4°C cardioplegia was flushed antegrade with aortic cannula (Group 1) or coronary catheterization ...


Assessment Of Normal Knee Kinematics Using High-Speed Stereo-Radiography System, Vasiliki Kefala Mar 2015

Assessment Of Normal Knee Kinematics Using High-Speed Stereo-Radiography System, Vasiliki Kefala

Electronic Theses and Dissertations

The measurement of dynamic joint kinematics in vivo is important in order to understand the effects of joint injuries and diseases as well as for evaluating the treatment effectiveness. Quantification of knee motion is essential for assessment of joint function for diagnosis of pathology, such as tracking and progression of osteoarthritis and evaluation of outcome following conservative or surgical treatment. Total knee arthroplasty (TKA) is an invasive treatment for arthritic pain and functional disability and it is used for deformed joint replacement with implants in order to restore joint alignment. It is important to describe knee kinematics in healthy individuals ...


Real-Time Bio Sensing Using Micro-Channel Encapsulated Mems Resonators, Ayesha Iqbal Aug 2014

Real-Time Bio Sensing Using Micro-Channel Encapsulated Mems Resonators, Ayesha Iqbal

Electronic Theses and Dissertations

This work presents a label-free bio-molecular detection technique based on realtime monitoring of the resonant frequency of micromechanical thermal-piezoresistive rotational mode disk resonators encapsulated in microfluidic channels. Mass loading via adsorption of molecular layers on the surface of such devices results in a frequency shift. In order to provide a reliable platform for sample-resonator interactions and to protect the resonators from contaminants, the resonators were encapsulated in PDMS-based microfluidic channels. Micro-channel encapsulation also allows insulation of electrical signals from the analyte solution. To characterize the performance of such devices as real-time label-free bio-molecular detectors, the strong non-covalent binding of Avidin ...


Design Of The High-Speed Stereo Radiography System, John C. Ivester Iv Aug 2014

Design Of The High-Speed Stereo Radiography System, John C. Ivester Iv

Electronic Theses and Dissertations

Orthopaedic pathologies often involve disruption of the mechanical environment of a joint at/below the mm scale. The ability to measure biomechanical kinematics at the sub-mm scale is essential for obtaining valuable insight into pathologies, but small motions of the joints are difficult to quantify. Estimates of skeletal kinematics are commonly made from optical motion capture systems and markers placed on the skin. The error caused by external marker movement is largely avoided with x-ray motion capture. Dynamic radiography uses a series of x-ray images recorded at high-speed and captures in-vivo joint motion. Uncovering the mechanical foundation of orthopaedic pathologies ...


Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali Nov 2013

Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali

Electronic Theses and Dissertations

Hip fracture remains a major public health concern due to the significant number of occurrences and mortality rates. Intertrochanteric fractures are the most common type of fracture and are typically caused by a fall. Intramedullary osteosynthesis is a common surgical practice to repair intertrochanteric fractures, but revisions are often required. The work presented in this thesis aims to improve the realism and fidelity of computational models of hip fracture, which can be an effective alternative to costly and labor-intensive clinical in-vivo and experimental in-vitro testing. Intersubject variability is inherently present in anatomy and material relations. Statistical shape and intensity models ...


Computational Biomechanical Modeling Of The Human Knee During Kneeling, Tariq R. Abo-Alhol Aug 2013

Computational Biomechanical Modeling Of The Human Knee During Kneeling, Tariq R. Abo-Alhol

Electronic Theses and Dissertations

Total knee replacement benefits patients who suffer from severe knee pain or joint stiffness and other joint related illnesses that limit everyday activities. There has been an increase in the number of procedures performed each year and a need to evaluate the performance of these implants during specialized activities such as kneeling. Most computational studies lack insight into inter-patient variability and the results do not apply to large population. This study developed: (1) three-dimensional explicit finite element (FE) models to investigate natural and implanted knee joint kinematics and bone strain and (2) a platform to enable population-based evaluation by combining ...


Modeling Hrtf For Sound Localization In Normal Listeners And Bilateral Cochlear Implant Users, Douglas A. Miller Jan 2013

Modeling Hrtf For Sound Localization In Normal Listeners And Bilateral Cochlear Implant Users, Douglas A. Miller

Electronic Theses and Dissertations

Mathematical models can be very useful for understanding complicated systems and for testing algorithms through simulation that would be difficult or expensive to implement. This dissertation presents a model that attempts to simulate the sound localization performance of persons using bilateral cochlear implants. The expectation is that this model could prove to be a useful tool in developing new signal processing algorithms for neural encoding strategies.

The head related transfer function (HRTF) is a critical component of this model, and in the ideal case, provides the base characteristics of head shadow, torso and pinna effects. This defines the temporal, intensity ...


Representing Intersubject Variability With A Statistical Shape And Alignment Model Of The Knee, Chandreshwar Rao Jan 2013

Representing Intersubject Variability With A Statistical Shape And Alignment Model Of The Knee, Chandreshwar Rao

Electronic Theses and Dissertations

Prior statistical shape models have not considered multiple structures in the knee joint to characterize anatomic variation which are required to investigate joint mechanics further for the successful knee replacement. Accordingly, the study's objective was to develop statistical shape and alignment model (SSAM) to capture intersubject variability and demonstrate the ability to generate realistic instances for use in finite element analysis (FEA). SSAM described the variability in the training set of 20 subjects with a series of modes of variation obtained by performing principal component analysis (PCA). PCA produced modes of variation with the first 3 modes representing 70 ...


Explicit Finite Element Modeling Of The Human Lumbar Spine, Milind Rao Jan 2012

Explicit Finite Element Modeling Of The Human Lumbar Spine, Milind Rao

Electronic Theses and Dissertations

Validated finite element (FE) models of the functional spinal unit (FSU) and lumbar spine are essential in design-phase device development and in assessing the mechanics associated with normal spine function and degenerative disc disease (DDD), as well as the impact of fusion and total disc replacement (TDR). Although experimental data from fully intact specimens can be used for model calibration and validation, the contributions from the individual structures (disc, facets, and ligaments) may be inappropriately distributed. Hence, creation of decompression conditions or device implantations that require structure removal may not have the proper resulting mechanics. An explicit FE formulation may ...


Electrohydrodynamic Atomization For Improved Macromolecular Drug Delivery, Michelle Zeles-Hahn Jan 2010

Electrohydrodynamic Atomization For Improved Macromolecular Drug Delivery, Michelle Zeles-Hahn

Electronic Theses and Dissertations

With advances in drug research, the use of biological therapeutics is becoming a reality. Unfortunately, methods for processing and delivering these fragile macromolecules often limit their therapeutic potential. For this dissertation, we explore the aerosolization of macromolecules by way of electrohydrodynamic atomization (EHDA) and how this method can be used to process and deliver therapeutics. EHDA employs a high voltage to break a column of liquid into drops. It was unknown if or how the residual charge left of the resulting droplets would affect lung cells. An in vitro experiment was conducted to spray aerosolized DNA, by way of EHDA ...


Parametric Model Of Head Related Transfer Functions Based On Systematic Movements Of Poles And Zeros With Sound Location For Pole/Zero Models, Bahaa W. Al-Sheikh Hussein Aug 2009

Parametric Model Of Head Related Transfer Functions Based On Systematic Movements Of Poles And Zeros With Sound Location For Pole/Zero Models, Bahaa W. Al-Sheikh Hussein

Electronic Theses and Dissertations

Directional transfer functions (DTFs), the directional components of the Head Related Transfer Functions (HRTFs), are generally measured at finite locations in azimuth and elevation. Thus models are needed to synthesize DTFs at finer spatial resolution than the measured data to create complete virtual auditory displays. In this research, minimum-phase all-pole and all-zero models were used for modeling both human and cat DTFs. Real cepstrum analysis has been used to represent minimum phase HRTFs in the time domain. For the human DTFs, model orders were chosen to achieve specific objective error criteria published in previous studies that were based on subjective ...