Biomedical Engineering and Bioengineering Commons^™

Muscle Synergies Improve Estimation Of Knee Contact Forces During Walking, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

This study investigates whether use of subject-specific muscle synergies can improve optimization predictions of muscle excitation patterns and knee contact forces during walking. Muscle synergies describe how a small number of neural commands generated by the nervous system can be linearly combined to produce the broad range of muscle electromyographic (EMG) signals measured experimentally. By quantifying the interdependence of individual EMG signals, muscle synergies provide dimensionality reduction for the neural control redundancy problem. Our hypothesis was that use of subjectspecific muscle synergies to limit muscle excitation patterns would improve prediction of muscle EMG patterns at the hip, knee, and ankle …

Muscle Synergy Constraints Improve Prediction Of Knee Contact Force During Gait, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

Knowledge of patient-specific muscle and joint contact forces during activities of daily living could improve the treatment of movement-related disorders (e.g., osteoarthritis, stroke, cerebral palsy, Parkinson’s disease). Unfortunately, it is currently impossible to measure these quantities directly under common clinical conditions, and calculation of these quantities using computer models is limited by the redundant nature of human neural control (i.e., more muscles than theoretically necessary to actuate the available degrees of freedom in the skeleton). Walking is a particularly important task to understand, since loss of mobility is associated with increased morbidity and decreased quality of life. Though numerous musculoskeletal …

Evaluation Of Different Optimal Control Problem Formulations For Solving The Muscle Redundancy Problem, Friedl De Groote, Allison Kinney, Anil Rao, Benjamin Fregly

Allison Kinney

This study evaluates several possible optimal control problem formulations for solving the muscle redundancy problem with the goal of identifying the most efficient and robust formulation. One novel formulation involves the introduction of additional controls that equal the time derivative of the states, resulting in very simple dynamic equations. The nonlinear equations describing muscle dynamics are then imposed as algebraic constraints in their implicit form, simplifying their evaluation. By comparing different problem formulations for computing muscle controls that can reproduce inverse dynamic joint torques during gait, we demonstrate the efficiency and robustness of the proposed novel formulation.

Material Properties And Microstructural Characterization Of Specimens, T.J. Silverman, Allison Kinney, B. South, W. Yong, J.H. Koo

Allison Kinney

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new software. This paper quantifies differences in mechanical and morphological properties of specimens built first using a Vanguard HS (high-speed) system and again using the same system with the HiQ upgrade applied. Standard specimens are built from DuraForm PA material and tested for tensile modulus, tensile strength, elongation at break, flexural modulus and Izod impact strength. The design of the specimen battery, the conduction of the tests and the significance of the results are discussed. The upgrade is found to …

Synergies Controls Improve Prediction Of Knee Contact Forces And Muscle Excitations During Gait, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

This study investigates whether use of muscle excitation controls constructed from subjectspecific muscle synergy information can improve optimization prediction of knee contact forces and muscle excitations during walking. Muscle synergies quantify how a large number of experimental muscle electromyographic (EMG) signals can be reconstructed by linearly mixing a much smaller number of neural commands generated by the nervous system. Our hypothesis was that controlling all muscle excitations with a small set of experimentally calculated neural commands would improve prediction of knee contact forces and leg muscle excitations compared to using independently controlled muscle excitations.

Comparison Of Material Properties And Microstructure Of Specimens Built Using The 3d Systems Vanguard Hs And Vanguard Hiq+Hs Sls Systems, T.J. Silverman, Allison Kinney, W. Yong, J.H. Koo

Allison Kinney

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new control software. The paper compares the tensile modulus, tensile strength, elongation at break, flexural modulus, Izod impact resistance and microstructure of two batteries of standard specimens built from recycled Duraform PA (Nylon 12). The first set is built on a Vanguard HS system and the second on the same system with the HiQ upgrade installed. The upgrade reduces user intervention, decreases total build time and improves surface finish. However, using the default processing parameters, tensile, flexure and impact properties …

Investigation Of The Inherent Chemical, Structural, And Mechanical Attributes Of Bio-Engineered Composites Found In Nature: Alligator Gar’S Exoskeleton Fish Scales, Wayne Derald Hodo

Graduate Theses and Dissertations

The U.S. Army has determined a huge cost savings of up to 51% can be accomplished by reducing the gross vehicle weight, for their personnel carrier, by 33%. To cut cost, composite materials are needed. Man-made composites can have superior material properties (high-strength, high-fracture toughness, and lightweight), but they are prone to delamination at the glued-layered interface. In contrast, fish scale is a natural composite that has the same material properties and, additionally, tend not to delaminate.

The focus of this study was to learn how nature integrates hard and soft materials at each length scale to form a layered …

Prediction Of Rupture In Abdominal Aortic Aneurysm, Qusay Alfaori

Graduate Theses and Dissertations

Studying the development of abdominal aortic aneurysm (AAA) through quantification of its growth kinetics and rupture criteria is important to decrease the risk of this life-threatening event. Uniaxial and biaxial testing of healthy and time-dependent Type-I collagen degraded aortic specimens from pigs was performed. Stress-strain suitable mathematical models describing the behavior of abdominal aortic tissue were utilized to derive specific tissue properties and parameters. Reduction in Type-I collagen fraction was observed using picrosirius red staining method, bright field microscopy, and MATLAB. Finite Element Modeling (FEM) of healthy and time-dependent Type-I collagen degraded abdominal aortas were performed using ABAQUS finite element …

Rupture In Abdominal Aortic Aneurysm, Qusay Alfaori

Graduate Theses and Dissertations

Quantification of abdominal aortic aneurysm development, its growth kinetics, and rupture criteria are important to decrease the risk of this life-threatening event. Uniaxial testing of healthy and collagen degraded aortic specimens from pigs was performed. A mathematical model, from the literature, for the stress-strain relationship that is suitable for describing the behavior of abdominal aortic tissue was used to derive specific tissue properties/parameters as a function of strain rate and as a function of specimen orientation. Analyses consisting of Finite Element Modeling of healthy and collagen degraded abdominal aortas were performed using ABAQUS finite element code and the measured properties. …

Effects Of Varus Knee Alignment And Using Toe-Cages On Frontal Plane Knee Biomechanics In Stationary Cycling, Guangping Shen

Masters Theses

Effects of varus knee alignment on the internal knee abduction moment (KAM) in walking has been widely studied. KAM has been shown to be closely associated with the development of medial knee osteoarthritis (OA). Despite the importance of the knee alignment, no studies have explored its effects on knee frontal plane biomechanics during stationary cycling. The purpose of this study was to examine the effects of varus knee alignment and using a toe-cage on the knee frontal plane biomechanics during stationary cycling. Eleven participants in each of the varus and neutral groups participated in the study. The participants performed in …

Effectiveness Of Group Kickboxing As A Means To Improve Gait And Balance In Individuals With Ms, Kurt Jackson, Kimberly Edginton Bigelow, Christina Cooper, Harold L. Merriman

Harold L. Merriman

In recent years, there has been a particular emphasis on identifying and delivering appropriate therapeutic interventions that address the significant balance and gait impairments that affect individuals with multiple sclerosis (MS). Group interventions implemented in community settings have been especially of interest, including tai chi classes. Recently, the authors conducted a preliminary study to examine whether group kick-boxing, which requires more vigorous movements, might be a feasible intervention. Initial findings showed promise and led the authors to pursue a more rigorous follow-up study, with the objective of determining whether a 5-week group kickboxing class improved clinical measures of balance and …

Modeling Viscoelastic Behavior In Compact Bone Through A Distribution Of Collagen D-Spacing: A Finite Element Analysis, Christopher Ha

Master's Theses

Osteoporosis affects nearly 54 million people in the United States. The cost associated with treatment is estimated to be $19 billion per year and is expected to grow yearly. D-spacing is the staggering of collagen molecules found at the nanoscopic level. Previously thought to have a constant value, recent studies have found that D-spacing has a distribution of values throughout the tissue. As part of an ongoing effort in understanding the mechanisms that are affected by osteoporosis, a finite element model was developed to explore the effects of D-spacing distribution on the viscoelastic material properties of bone tissue. The goal …

الگو و دستورالعمل تهيه و تدوين پايان نامه کارشناسي ارشد, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Effect Of Hemiarthroplasty Implant Contact Geometry And Material On Early Cartilage Wear, Alana Khayat

Electronic Thesis and Dissertation Repository

Hemiarthroplasty is a minimally invasive, cost-effective alternative to total arthroplasty in joints of the upper limb. Though these procedures reduce patient morbidity while restoring joint kinematics, their longevity is limited by wear of the adjacent cartilage. This work investigates the roles of contact geometry and implant stiffness on cartilage wear with the aim of elucidating the mechanics that contribute to cartilage damage. An in vitro study examined the influence of implant geometry on cartilage wear using a pin-on-plate wear simulator. A significant decrease in volumetric wear was observed as contact area increased, which suggests that maximizing contact area should be …

Investigation Of Bovine Serum Albumin (Bsa) Attachment Onto Self-Assembled Monolayers (Sams) Using Combinatorial Quartz Crystal Microbalance With Dissipation (Qcm-D) And Spectroscopic Ellipsometry (Se), Hanh T.M. Phan, Shannon L. Bartelt-Hunt, Keith B. Rodenhausen, Mathias Schubert, Jason C. Bartz

Department of Civil and Environmental Engineering: Faculty Publications

Understanding protein adsorption kinetics to surfaces is of importance for various environmental and biomedical applications. Adsorption of bovine serum albumin to various selfassembled monolayer surfaces including neutral and charged hydrophilic and hydrophobic surfaces was investigated using in-situ combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry. Adsorption of bovine serum albumin varied as a function of surface properties, bovine serum albumin concentration and pH value. Charged surfaces exhibited a greater quantity of bovine serum albumin adsorption, a larger bovine serum albumin layer thickness, and increased density of bovine serum albumin protein compared to neutral surfaces at neutral pH value. The …

Characterization Of Electrophorectic Separations On A Cellulose Paper-Microfluidic Chip, Kyle Robert Fast

Master's Theses

The purpose of this thesis project is to demonstrate the ability to utilize electrophoresis in a cellulose paper microfluidic chip to manipulate charged particles. Materials were selected and a manufacturing protocol was created to successfully apply the electric field onto the paper chip. Experiments were performed to characterize the separation rates for charged, colorimetric dye, Orange G in the membrane as a function of an applied electric field, dye concentration, and distance traveled. The experiments confirmed that the electric field can be applied to the chip and particle separation rates were characterized. Next, the determined rates results were used to …

Blood Supply To The Brain Via The Carotid Arteries: Examining Obstructive And Sclerotic Disorders Using Theoretical And Experimental Models, Onaizah Onaizah

Electronic Thesis and Dissertation Repository

Stroke remains one of the leading causes of death in North America. Approximately half of all ischemic episodes are a direct result of carotid artery disease, which can be categorized into either obstructive or sclerotic disease. Obstructive disease is a result of plaque development that imposes a direct limitation on the physical space available for blood flow. Sclerotic disease involves the hardening of the arteries as is often a result of aging and disease. While the impact of vessel stiffening is not as obvious, it does interfere with wave propagation. Effects of obstructive and sclerotic disease were studied using a …

Three-Dimensional Confocal Microscopy Indentation Method For Hydrogel Elasticity Measurement, Donghee Lee, Md Mahmudur Rahman, You Zhou, Sangjin Ryu

Md Mahmudur Rahman

No abstract provided.

Changes In Vessel Properties During Early Progression Of Murine Abdominal Aortic Aneurysms From In Vivo Ultrasound, Luis R. Avila Murati, Evan H. Phillips, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAA) are a common and frequently fatal disease characterized by the weakening and dilation of the aorta. The larger the aneurysm, the higher the chances are of rupturing and life-threatening hemorrhage. The aim of this study is to apply the angiotensin II (AngII) model of AAAs in male apolipoprotein-E-deficient mice (apoE^-/- C57Bl/6J), in order to analyze, quantify, and understand the pathologies and characteristics associated with early AAA development. To date, many studies focusing on the evaluation of AAA characteristics have been performed ex vivo. Therefore, we focused on in vivo assessment, through the use of …

In Vivo Mechanics Of Cam-Post Engagement In Fixed And Mobile Bearing Tka And Vibroarthrography Of The Knee Joint, Sumesh M. Zingde

Doctoral Dissertations

The objective of this dissertation was to determine the mechanics of the cam-post mechanism for subjects implanted with a Rotating Platform (RP) PS TKA, Fixed Bearing (FB) PS TKA or FB Bi-Cruciate Stabilized (BCS) TKA. Additionally, a secondary goal of this dissertation was to investigate the feasibility of vibroarthrography in correlating in-vivo vibrations with features exhibited in native, arthritic and implanted knees. In-vivo, 3D kinematics were determined for subjects implanted with nine knees with a RP-PS TKA, five knees with a FB-PS TKA, and 10 knees with a FB-BCS TKA, while performing a deep knee bend. Distance between the cam-post …

A Continous Rotary Actuation Mechanism For A Powered Hip Exoskeleton, Matthew C. Ryder

Masters Theses

This thesis presents a new mechanical design for an exoskeleton actuator to power the sagittal plane motion in the human hip. The device uses a DC motor to drive a Scotch yoke mechanism and series elasticity to take advantage of the cyclic nature of human gait and to reduce the maximum power and control requirements of the exoskeleton. The Scotch yoke actuator creates a position-dependent transmission that varies between 4:1 and infinity, with the peak transmission ratio aligned to the peak torque periods of the human gait cycle. Simulation results show that both the peak and average motor torque can …

A Finite Element Analysis On The Viscoelasticity Of Postmenopausal Compact Bone Utilizing A Complex Collagen D-Spacing Model, Austin C. Cummings

Master's Theses

The nanoscale dimension known as D-spacing describes the staggering of collagen molecules, which are fundamental to the biphasic makeup of bone tissue. This dimension was long assumed to be constant, but recent studies have shown that the periodicity of collagen is variable. Given that the arrangement of collagen molecules is closely related to the degree of bone mineralization, recent studies have begun to look at D-spacing as a potential factor in the ongoing effort to battle postmenopausal osteoporosis. The theoretical models presented by previous studies have only opted to model a single collagen-hydroxyapatite period, so the creation of an intricate …

Development And Validation Of A Tibiofemoral Joint Finite Element Model And Subsequent Gait Analysis Of Intact Acl And Acl Deficient Individuals, Nicholas Czapla

Master's Theses

Osteoarthritis (OA) is a degenerative condition of articular cartilage that affects more than 25 million people in the US. Joint injuries, like anterior cruciate ligament (ACL) tears, can lead to OA due to a change in articular cartilage loading. Gait analysis combined with knee joint finite element modeling (FEM) has been used to predict the articular cartilage loading. To predict the change of articular cartilage loading during gait due to various ACL injuries, a tibiofemoral FEM was developed from magnetic resonance images (MRIs) of a 33 year male, with no prior history of knee injuries. The FEM was validated for …

Modeling The Contributions Of Hand Loads To Cervical Spine Compressive Forces, Mohamed R.S. Amar

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The purpose for this study is threefold. All involve single handed lifting tasks where the height of the lifted object, the distance of the lifted object from the body, and the angle of the lift relative to the body were varied. First, examine the activity of each of the shared musculature of selected shared muscles between the shoulder and cervical spine. Second, attempt to empirically model the activations of the shared muscles. Third, to understand the relationship between the active and antagonistic contraction. Finally, to establish a biomechanical model to estimate the compressive forces on the cervical spine.

Ten subjects …

Support For New Course Development For Introduction To Biomechanics, Allison Kinney

Allison Kinney

Funded research sponsored by the University of Dayton KEEN Fellows Cohort. Awarded $13,000.

Osteoarthritis Induced Glenoid Morphology And Bone Quality: An Evaluation Of Augmented Glenoid Components, Nikolas K. Knowles

Electronic Thesis and Dissertation Repository

Osteoarthritis of the glenoid results in regional bone density variations and bone loss that may compromise early component fixation and support. The two common morphologies, symmetric and asymmetric erosion, were characterized by bone density and morphology, and assessed on the basis of bone removal and bone quality in the context of augmented glenoid components. The bone strain field was also compared when different augmented glenoid components underwent simulated joint loading using finite element analysis.

Asymmetrically eroded glenoids were found to have denser bone (p

A Three Constituent Mixture Theory Model Of Cutaneous And Subcutaneous Tissue In The Context Of Neonatal Pressure Ulcer Etiology And Prevention, Anne Dye Zakrajsek

Open Access Dissertations

Localized ischemia, impaired interstitial fluid flow, and sustained mechanical loading of cells have all been hypothesized as mechanisms of pressure ulcer (PrU) etiology. Time-varying loading has experimentally been shown to increase fluid flow in human skin in vivo. Towards the design of prophylactic protocols and treatment modalities for PrU management there is a need for an analytical model to investigate the local fluid flow characteristics of skin tissue under time-varying loading. In this study, a triphasic mixture theory model with constituents of extracellular matrix, interstitial fluid, and blood was calibrated and validated and used to investigate stress and fluid velocity …

Characterization And Evaluation Of Head Impact Sensors And Varsity Football Helmets, Brian R. Cummiskey

Open Access Theses

An increased understanding of the effects of brain injury in recent years has led to greater attention being given to the topic. A desire to investigate the causal agents of these injuries in athletes has led to the development and use of several devices that track head impacts as well as improving helmet technology to protect players from said impacts. In order to determine which devices are able to best measure head impacts, a Hybrid III headform was used to quantify the accuracy for translational and angular accelerations. Testing was performed by means of administering impacts to a helmet on …

Measurement, Characterization, And Effects Of Head Impacts In Women's Soccer, Emily C. Mccuen

Open Access Theses

The potential for long term neurological deficits resulting from repetitive head trauma is a major concern for collision sport athletes. Research conducted on football played has found neurophysiologic changes in the absence of concussion in athletes as early as high school age. Given that female soccer players show the highest rate of concussion for female athletes and a higher rate of concussion than their male counterparts, it is important to characterize the types of impacts female soccer athletes receive and assess female soccer athletes for neurophysiologic changes due to these impacts. This work paired head impact sensors with functional MRI …

Magnetic Manipulation And Multimodal Imaging For Single Cell Direct Mechanosensing, Robert L. Wilson

Open Access Theses

The study of internal mechanics of single cells is paramount to understand mechanisms of mechanoregulation. External loading and cell-mediated force generation result in changes in cell shape, rheology, and the deformation of subcellular structures such as the nucleus. Moreover, alterations in the processes that regulate these responses have been further correlated to specific pathologies. Cellular deformation is often studied through application of forces in the environment of the cell, relying on strain and stress transfer through focal adhesions and the cytoskeletal system. However, the transfer of these external forces to internal mechanics can introduce uncertainties in the interpretation of subcellular …