Master of Science, University of Toledo, 2020, Mechanical Engineering

Osteoarthritis is one of the oldest recorded diseases that can impair movement and cause pain—affecting over half of the elderly community, osteoarthritis of the acromioclavicular joint is one of the most common sources of shoulder pain due to its ability to break down tissues within a joint due to repeated mechanical loadings. These loading repetitions eventually begin to form osteophytes at the articulating surfaces of the joint effectively increasing the stress at the joint and decreasing the spacing. Due to this decrease of space, the clinical physical examinations done involve moving the arm into positions that decrease the space further causing acute pain at the joint. One of the current standard clinical physical examination tests is the Cross Body Adduction test which has been shown to close the joint spacing a significant enough amount to cause irritation and signal the presence of osteoarthritis. However, a new test involving placing the hand behind the back, called the Reverse Shoulder Internal Rotation Test—also referred to as the Hand Behind the Back test—has been proposed after it was observed clinically to provide a more accurate osteoarthritis diagnosis than the Cross Body Adduction test for some patients. Through this work, both the Cross Body Adduction and Hand Behind the Back tests were modeled in order to determine if there is merit for the Hand Behind the Back test to be used as a diagnostic tool for clinicians. Both tests were modeled using the Zygote Solid 3D 50th Percentile Male Human Anatomy model (ZYGOTE, American Fork, UT) for the bone 3D models and MSC.ADAMS (MSC Software, Newport Beach, CA) to compile and run the simulations. Within MSC.ADAMS the bones were given compact bone material properties and were outfitted with joints, single-component forces for muscles, springs for ligaments, and normal to the rib's tangent springs to simulate the scapulothoracic articulation. Once the models were completed, the simulations were ran and it w (open full item for complete abstract)

Committee: Mohamed Samir Hefzy (Committee Chair); Brian Trease (Committee Member); Abdulazim Mustapha (Committee Member); Adam Schroeder (Committee Member) Subjects: Biomechanics; Engineering; Mechanical Engineering

Master of Science, The Ohio State University, 2017, Mechanical Engineering

The use of a manual wheelchair (MWC) for everyday mobility is associated with some degree of biomechanical risk, particularly to the user's trunk and upper extremities (UE), due to the loads placed on the body during propulsion and transfers. An improperly fitting wheelchair can require users to exert higher force or result in awkward positions that can place unnecessary strain on the UE. The combination of repetitive motion, higher peak forces and large joint deflections may result in musculoskeletal problems or injuries. Clinical fitting methodologies are primarily categorical and qualitative and as such are based on the clinician's perception and previous experience. Therefore, they do not provide a good basis for quantitative prediction of the impact of the wheelchair system on the user's biomechanics and the associated risk for developing additional musculoskeletal problems. Recent studies have focused on the identification of MWC user UE injuries and clinical prescription adjustments to prevent those injuries. While many adjustments have been supported using experimental data, computational modeling allows for a wider range of test case scenarios and the inclusion of additional factors that cannot be easily estimated in vivo, including the impact of deviations and changes to a wheelchair prescription on the user's force generation capabilities and more accurate risk identification. A few biomechanical models exist in current literature, but they are not adaptable for widespread use, utilize private software, are subject-specific or are insufficient in analyzing the user and wheelchair system. The MWC Propulsion Model 2017, created in OpenSim software by adapting a previously validated walking biomechanical model for application to a MWC and user, seeks to overcome the limitations of existing models, including accounting for a larger number of degrees of freedom and asymmetry. At this stage, the MWC Propulsion Model 2017 serves as a clinical teaching tool, (open full item for complete abstract)

Committee: Sandra Metzler (Advisor); Robert Siston (Committee Member); Carmen DiGiovine (Committee Member) Subjects: Biomechanics; Engineering; Health Sciences; Rehabilitation

Master of Science, The Ohio State University, 2023, Industrial and Systems Engineering

Introduction: Musculoskeletal disorders in the workforce are highly prevalent, especially in material handling operations. In addition to completing physically demanding work that is required in this domain, workers must also manage concurrent mental demands present in their tasks. Few studies have examined the effect of concurrent mental demands in occupationally-relevant tasks. This study attempted to fill this void by quantifying the effects of varying degrees of cognitive loads and task precision demands on a material handling task by examining these effects on the kinematics and muscle activity of the trunk and shoulders. Methods: Twelve subjects lifted and placed a 5 kg box on a rack at one of three destination heights (low, middle, high) while under a simultaneous cognitive load (no load, simple load, complex load) and/or precision constraint (low precision, high precision). Cognitive load consisted of time-based arithmetic questions where participants were tasked with determining the amount of time remaining from a given time to a target time (e.g., Get to 4:00 PM from 3:15 for simple load or get to 4:10 PM from 3:27 PM for complex load). The primary dependent measures were the angular velocities of the trunk and shoulders as well as muscle activity in the erector spinae, rectus abdominus, external oblique, latissimus dorsi, and anterior deltoid muscles. Results: Significant decreases in angular velocities for both higher cognitive load complexities and higher precision conditions were observed. Additionally, lower 90th percentile normalized muscle activity values were observed as complexity and precision increased. Cumulative muscle activity, however, increased with these increases in complexity and precision. Conclusions: This study examined the impact of varying levels of cognitive and precision conditions on muscle activity and kinematics of the trunk and shoulders. Results indicated that increased complexity and precision led to longer lift t (open full item for complete abstract)

Committee: Carolyn Sommerich (Committee Member); Steven Lavender (Advisor) Subjects: Behavioral Sciences; Biomechanics; Engineering; Health Sciences; Industrial Engineering; Kinesiology; Occupational Safety

Doctor of Philosophy, Case Western Reserve University, 2022, Biomedical Engineering

Functional electrical stimulation (FES) can restore motor function to people with paralysis caused by spinal cord injuries (SCIs). Recently, deep neural networks (DNNs) trained with reinforcement learning (RL) have been explored as a promising methodology to control upper-limb FES systems. By emulating natural learning, RL may eliminate labor-intensive manual adjustments of controller parameters. However, previous studies did not consider musculoskeletal systems with highly fatigable and atrophied muscles, such as those observed in people with chronic paralysis. Here, we implemented a fatigable Hill-type musculoskeletal model to investigate the RL control of chronically paralyzed muscles. We discovered that RL controllers using Twin Delayed Deep Deterministic Policy Gradients (TD3) and Hindsight Experience Replay (HER) could effectively control a fatigable horizontal planar model of the human arm, as long as the arm was given sufficient rest between motor tasks. Also, muscle weakness and increased muscle stiffness caused by chronic paralysis considerably decreased the workspace of the arm. Finally, by incorporating negatively biased layer normalization, it was possible to decrease the muscle activations commanded by RL controllers while maintaining high performance. The results in the present study support the feasibility of using RL control to restore upper-limb motor function to people with SCIs, and we hope that they will inform the design of effective FES controllers that can be more easily translated into clinical practice.

Committee: Robert Kirsch (Advisor) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research; Rehabilitation

Master of Science in Exercise Science, University of Toledo, 2022, Exercise Science

Context: Many factors have been previously examined in relation to anterior cruciate ligament (ACL) injury, including neurocognition and corticomotor function. Those with lower neurocognition and corticomotor function display landing biomechanics and muscle function that may increase risk of injury. However, it is not known if poor landing mechanics resulting from the addition of a dual task may be exacerbated by diminished corticospinal excitably or neurocognitive function. Objective: Investigate the relationships between neurocognitive performance and corticomotor function and biomechanical dual-task cost during a landing assessment. Design: Descriptive laboratory study. Setting: Laboratory. Patients or Other Participants: 18 physically active (Tegner Activity Level ≥ 5), healthy females between the ages18 and 30 years old. Participants with a history of lower extremity surgery, history of lower extremity injury in the past 6 months, documented exclusion criteria for transcranial magnetic stimulation(TMS) were excluded. Intervention(s): Participants will complete single leg squats, a computer-based neurocognitive assessment, jump landing task, memory exercises, and mental arithmetic. Main Outcome Measures: Corticospinal excitability was assessed through active motor threshold measured by TMS during a single leg squat. Kinematic and kinetic data of the knee, hip, ankle, and trunk were assessed with 12 camera 3D analysis. Neurocognitive function was assessed through composite scores of the ImPACT. Results: For the number dual task cost, there was a moderate negative correlation between visual motor composite score and knee flexion angle. For the visual dual task cost, there was a moderate negative correlation between active motor threshold and hip adduction angle. Conclusions: Worse neurocognition and corticospinal excitability are associated with changes in landing patterns consistent with greater knee flexion angles and more neutral hip positions d (open full item for complete abstract)

Committee: Grant Norte (Committee Chair); Amanda Murray (Committee Member); David Bazett-Jones (Committee Member) Subjects: Biomechanics; Kinesiology; Sports Medicine

Master of Science in Biological Sciences, Youngstown State University, 2021, Department of Biological Sciences and Chemistry

The calcaneal (Achilles) tendon is capable of handling tremendous tensile loads during locomotion. However, cases of Achilles tendon ruptures have increased in recent years, requiring long healing times. Repaired tendons are more prone to re-rupture after healing, which may negatively impact patient quality of life. Thus, there exists a need for new methods of treatment aimed to improve and accelerate tendon healing. We studied the effect a combination of collagen, platelet-rich plasma (PRP), and mesenchymal stromal cells (MSC) on healing a complete Achilles tendon rupture in a Lewis rat model. The PRP was produced from rat blood collected during exsanguination procedures. MSCs from rat bone marrow met the criteria to be considered stem cells in a rat model, as they were seen to be plastic adherent and capable of tri-lineage differentiation. Rupture was surgically simulated by a full-thickness transection of the tendon, followed by surgical repair. All treatments included a strip of CollaTapeTM wrapped around the repair, acting as a vehicle for the biologics prior to closure of the wound. A single, 100µL subcutaneous injection of MSCs, PRP, or both were administered adjacent to the incision and assigned 1- or 2-week recovery periods before harvesting the operated and unoperated tendons. We observed promising trends which show an increase in gene expression activity in the treated tendons and differences in the expression of Col1a1 and Col3a1 which align with our predicted response to the treatments. However, due to contamination of the GAPDH RT-PCR results, the collagen analysis results remain inconclusive. The biomechanical properties of the tendons were determined using force-extension analysis. When normalized as a percent of the unoperated tendon, a significant improvement was seen in the strain at failure and in ultimate tensile strength after only one week of recovery in the rats who received any biological treatments used in this study, when compared to a sur (open full item for complete abstract)

Committee: Diana Fagan PhD (Advisor); Gary Walker PhD (Committee Member); Carmen Panaitof PhD (Committee Member) Subjects: Biology; Biomechanics; Biomedical Research; Physiology; Surgery

Doctor of Philosophy, The Ohio State University, 2022, Industrial and Systems Engineering

Low back pain (LBP) and neck pain (NP) arise from complex interactions among physical, psychological, and social stressors. One psychological stressor that may play a role in the etiology of low back and neck pain but has not yet been studied relative to spinal injury is cognitive dissonance. Originally introduced by Leon Festinger in 1957, Cognitive Dissonance Theory (CDT) posits that humans strive for psychological consistency and experience both psychological discomfort and physiological arousal when their beliefs, values, or behaviors are placed at odds with the world around them. These psychological and physiological effects, known as the cognitive dissonance state (CDS), may also yield biomechanical changes that increase the risk of experiencing spinal injury. Thus, the objective of the study was to explore the potential association between cognitive dissonance and low back/neck pain injury risk. A laboratory study was conducted to examine the effects of the CDS on psychological, physiological, and biomechanical factors associated with LBP and NP injury risk. Seventeen healthy subjects (ages 19-44) participated in the experiment, which involved a precision lowering task. To elicit the CDS, subjects were provided negative feedback on their task performance that ran counter to a pre-established expectation that their performance on the task was excellent. Dependent measures included changes to positively and negatively oriented psychological affect, changes to blood pressure, changes to heart rate variability (HRV), and changes to spinal loads in the cervical and lumbar spines (calculated via two electromyography-assisted biomechanical models). Providing subjects with negative feedback inconsistent with their expectations yielded changes to positively and negatively oriented affect and blood pressure consistent with the CDS, but main effects of the CDS condition on HRV were opposite of expected. However, there was substantial variability in the psychologic (open full item for complete abstract)

Committee: William S. Marras (Advisor); Afton L. Hassett (Committee Member); Tristan E. Weaver (Committee Member); Carolyn M. Sommerich (Committee Member) Subjects: Biomechanics; Industrial Engineering; Social Psychology

Doctor of Philosophy, The Ohio State University, 2020, Industrial and Systems Engineering

Office computer users experience work-related musculoskeletal disorders including pain in the neck, shoulders, and lower back. Previous researchers revealed that there were associations between the cognitive workload imposed by computer tasks and the increased biomechanical load which could eventually lead to adverse symptoms. However, there are limited data that describe how the different components of cognitive workload are associated with changes in computer users' biomechanical response to the work process. At the same time, although furnishings with lumbar support and relevant sitting guidelines have been provided in many office settings, there is limited evidence showing more supportive furniture is effective in reducing the risk of musculoskeletal disorders (MSDs) among office computer users. This study investigated: 1) whether computer users are sitting in the suggested neutral position and using the backrest when working on different types of computer tasks; 2) how the causal (task complexity and time pressure) and assessment factors (mental demand, mental effort, and task performance) of cognitive workload are related with the variations in computer users' biomechanical responses; and 3) whether using a footrest can be used to promote the use of backrest in computer tasks. The first stage of this dissertation was an observational study in which computer users' sitting postures were observed and recorded discretely as the observed individuals worked on different types of computer tasks. The findings revealed that chairs' back supports were not being used effectively that the users did not rest their whole back against the backrest. Following the observational study, a laboratory experiment was conducted to investigate how the computer tasks that varied in their level of cognitive workload, which was assessed in terms of mental demand, mental effort, and task performance, are associated with the variations in the computer users' biomechanical responses (open full item for complete abstract)

Committee: Steven Lavender (Advisor); Carolyn Sommerich (Committee Member); Michael Rayo (Committee Member) Subjects: Biomechanics; Design; Industrial Engineering; Occupational Health

Master of Science in Engineering, Youngstown State University, 2019, Department of Mechanical, Industrial and Manufacturing Engineering

It is estimated that about 18 out of 100,000 people rupture their Achilles tendon every year. A review of 4000 Achilles tendon ruptures found that 75% were related to sports activities. Currently, the methods for fixing Achilles tendon ruptures are in need of improvement. Due to the prevalence of Achilles tendon injuries in sports and the fact that tendons have poor wound healing, there has been an abundance of studies on treatments for Achilles tendon injuries. Many different techniques and therapies using biologics have been researched. One area, however, that has not been well researched is the addition of a combination of mesenchymal stromal cells and platelet-rich plasma as a treatment method for wound healing enhancement. There is also a lack of studies comparing different treatment methods as they progress through time. This study chose the following treatment methods: collagen (CoTa); collagen and platelet-rich plasma (PRP); collagen and mesenchymal stromal cells (MSC); and collagen, platelet-rich plasma, and mesenchymal stromal cells (CPM) to follow through two recovery times: 1 week and 2 weeks. Lewis rats were chosen and a full transection of the right Achilles tendon was performed 6 mm proximal to the calcaneal bone. At 1 or 2 weeks both Achilles tendons of the rats were extracted and tensile tests were performed. Maximum force, engineering stress, strain, modulus of elasticity, total strain energy, and elastic strain energy were determined. Differences in the treatment groups at 1 week recovery were notable, no differences were found between the treatment groups at 2 week recovery, however differences could be seen when compared to the left virgin tissue controls. Computational modeling led to preliminary finite element models for each treatment group. Validation for each model was achieved by comparison with experimental data. Further development of the finite element analysis would allow for a more accurate model and allow for better comparisons betwe (open full item for complete abstract)

Committee: Hazel Marie PhD (Advisor); Diana Fagan PhD (Committee Member); Virgil Solomon PhD (Committee Member); Jason Walker PhD (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research

Doctor of Philosophy, The Ohio State University, 2017, Mechanical Engineering

All biological motion is ultimately driven by molecular scale interactions and forces. Only in recent years have technologies and techniques been developed capable of probing interactions at forces of nanoNewtons to picoNewtons, and at length scales of Microns to Angstroms. However, these techniques (such as Optical Traps, Magnetic Tweezers, and Atomic Force Microscopy) are limited in their potential applications by their physical size and low experimental throughput. This dissertation presents the development of a DNA Origami based nanosensor, specifically designed to perform high-throughput, single-molecule force spectroscopy measurements. DNA Origami is a nanofabrication process driven by the specificity of Watson-Crick nucleobase pairing. By engineering the sequence of a series of oligonucleotides, Megadalton scale assemblies can be assembled through a molecular self-assembly process at the nanoscale. Here, we exploit this technique to utilize the entropic elasticity of the DNA molecule, generating a force on a bimolecular interaction the nanostructure facilitates. This interaction is monitored via an optical technique, Forster Resonance Energy Transfer, enabling high throughput and multiplexed measurements of biomolecular binding kinetics. Additionally, specific control over spatial arrangement and stiffness of these DNA Origami nanostructures makes them useful as nanoscale measurement tools. We have designed a second nanostructure to explore the role of local ligand flexibility on the strength of cellular signaling. A DNA Origami nanostructure was developed – A nanoscale platform incorporating biomolecular linker DNA strands of varying length and stiffness. Antibodies specific to a transmembrane receptor expressed on B cells were affixed to these nanostructures, and the complexes used to probe the parameters governing cellular signaling. However, traditionally DNA Origami is limited by small physical production scales, high costs, and sophisticated fabri (open full item for complete abstract)

Committee: Carlos Castro (Advisor) Subjects: Mechanical Engineering

Master of Science (MS), Ohio University, 2017, Biomedical Engineering (Engineering and Technology)

The role mechanical properties play in the interconnected network of cellular control mechanisms is becoming better understood. Specifically, mechanical stiffness has been shown to be a marker capable of distinguishing between malignant and benign cancer phenotypes. Traditional techniques to measure cell stiffness share the commonality of low throughput. Microfluidic technology has been used to attain stiffness related data at a high throughput, however data collection and analysis is almost exclusively reliant on video spectroscopy. Through the use of a serial multi-constriction microfluidic device, cell ease of transit, i.e., agility, can be measured by the transit through the serial network developed herein. This measure of agility has the capability to differentiate cells based on phenotype, specifically phenotypes characteristic of the epithelial-to-mesenchymal transition, EMT, which occurs in cancer cells upon initiation of metastasis. By developing a compatible microfluidic sensor, the post processing of cell agility data has the potential to be automated and moved toward a non-video spectroscopy dependent system. These improvements push the technology of cellular mechanical property data analysis toward a faster, more convenient platform, thus allowing a better understanding of how mechanical properties correspond with biological behavior of mammalian cells.

Committee: Monica Burdick Dr. (Advisor); Robert Williams Dr. (Committee Member); Douglas Goetz Dr. (Committee Member); Allan Showalter Dr. (Committee Member) Subjects: Biomechanics; Biomedical Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2016, Mechanical Engineering

Posturography is the study of an individual's regulation of balance and much posturography research is dedicated to studying the effect of aging on postural control. The study of the postural stability of this population is motivated by a need to understand physiological changes caused by the aging process in older adults. While posturography is commonly used in research with older adults, there is need to improve and enhance current data collection procedures and data analysis approaches. This work identified and addressed four research gaps in current posturography knowledge with an emphasis on older adult populations. A single session of data collection was conducted to obtain the necessary data for each aim which were then each addressed independently. Ninety older adults participated in this research. The objective of the first aim was to evaluate use of Time to Stabilization method to gauge the stabilization time for older adults stepping onto a firm and a compliant surface, with an emphasis on first identifying methods to assess the appropriateness of the data trend and to determine the success of the curve fit. The results of this study suggest the majority of older adult data is appropriate for this analysis. The authors suggest using a signal-to-noise cutoff of 2.5 when evaluating data trends and a R2 cutoff of .25 when evaluating curve fit. The objective of the second aim was to determine if incorporating a foam surface, nonlinear analysis, and age stratification would improve the insightfulness of the Limits of Stability (LOS) assessment. The findings of this work indicated differences in LOS performance between age groups and that the assessment benefits from nonlinear analysis. The objective of the third aim was to determine whether LOS assessment inertial measurement unit (IMU)-based outcome measures demonstrated greater differences between fallers and non-fallers than the traditional center of pressure (COP)-based outcome measures. The results showe (open full item for complete abstract)

Committee: Kimberly Bigelow Ph.D. (Advisor) Subjects: Biomechanics; Mechanical Engineering

MS, University of Cincinnati, 2015, Engineering and Applied Science: Biomedical Engineering

Cartilage rings in the trachea are primarily responsible for structural stability of the trachea and to prevent its collapse over the range of intrathoracic pressures encountered in-vivo. The underlying biomechanical properties of the cartilage rings critical to this function are unknown. This study was designed to determine the zero stress state, structural properties – initial and tangent stiffness, and load relaxation (% of initial load) of the tracheal rings and material properties of the tracheal cartilage. These properties would eventually be used to create the biomechanical design requirements for a tracheal exostent which would then be used in pediatric patients suffering from long segment congenital tracheal stenosis. Primary goal of this study was to determine the inter-animal variations of these properties for 3-6 month old lamb and to determine if these properties vary within animals with the anatomical location of the ring on the trachea. Cartilage rings were isolated from the cranial, mid and caudal sections of tracheas from eight lambs (3-6 month old). The rings were cut posteriorly to allow them to reach zero stress state and corresponding opening angles were measured. The rings at zero stress state were further tested either in radial tension or radial compression at a constant rate of deformation. The rings tested in radial tension were held at a constant radial displacement at the end of the test and load relaxation was recorded over 15 minutes. The data from these tests was used to calculate the initial and tangent stiffness and load relaxation of the rings. Modulus was calculated from analytical models for the ring test configurations based on curved beam theory. The results obtained showed large inter-animal variations in the tracheal ring major and minor diameters, width and thickness of rings (geometry at no-load), opening angle (zero stress state geometry), initial and tangent stiffness, load relaxation and modulus. Moreover, the minor d (open full item for complete abstract)

Committee: Balakrishna Haridas PH.D. (Committee Chair); Farhan Zafar M.D. (Committee Member); Vasille Nistor Ph.D. (Committee Member); Marepalli Rao Ph.D. (Committee Member) Subjects: Engineering

Master of Science, University of Akron, 2013, Biomedical Engineering

Adolescent idiopathic scoliosis is a three-dimensional spinal curve deformity that often requires surgery and instrumentation to correct. The Ponte osteotomy is a surgical resection technique used to realign the spine from a posterior-only approach, in an aim to better correct the spinal deformity. Less aggressive resection techniques such as facetectomy are currently being used in conjunction with posterior instrumentation systems. The goal of surgery is to achieve a stable, well-balanced spine by reducing the magnitude of the deformity and then fusing the spine in order to prevent curve progression. The biomechanical effects that are produced by these two techniques have not been evaluated previously. The current study implemented in vitro biomechanical flexibility tests in repeated measures fashion to determine differences in three-dimensional rotations achievable between (1) facetectomy and (2) Ponte osteotomy. Eight 56 to 87-years-old (mean = 72) cadaveric thoracolumbar multi-segment (T4-T10) specimens (six female, one male, one unrecorded) were used. A custom-built flexibility testing machine was used to apply 5 continuous cycles of pure bending moment to ± 4 Nm at a rate of 1°/s while allowing the motion of each specimen to remain unconstrained. Three separate pure bending moments were applied for each specimen, for 5 cycles, in the following directions: axial rotation (AR); lateral bending (LB); and flexion/extension (FE). An optoelectronic camera system (NDI Optotrak Certus) was used to capture the 3D kinematics of T9, T8, T7, T6, T5, and T4. The load-displacement data collected during the last loading cycle were analyzed to determine the range of motion (ROM) achieved by the intact spinal column. The tests were repeated and analyzed after facetectomy and again after Ponte osteotomy. Significant differences were found in the overall multi-segment ROM after Ponte osteotomy, compared to the ROM increase after facetectomy alone. Single factor ANOVA test (open full item for complete abstract)

Committee: Marnie M. Saunders Dr. (Advisor); Mary C. Verstraete Dr. (Committee Member); Narender P. Reddy Dr. (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research; Design; Engineering; Experiments; Health Care Management; Mechanics; Statistics; Surgery

Master of Science in Engineering (MSEgr), Wright State University, 2010, Biomedical Engineering

Locking compression plates are proven to be safe for use in open reduction and internal fixation (ORIF) especially in osteoporotic bones. Because of various combinations of holes, the system provides more options for clinicians to use either locking screws or non-locking screws. This clinical research introduces screw like plugs which can be used along with the screws in case of locking compression plates. Experimental work was performed to determine the effectiveness of the plugs. The results showed that there is not a significant difference between the groups which used plugs and did not use the plugs, both in case of axial and torsion test conditions. This study demonstrates the initial work performed on the plugs and further studies are required to examine the effectiveness of constructs. If proven, this technique will contribute towards the treatment of the fracture using Locking Compression Plates and also it will be helpful in designing better locking compression plates with lower stiffness and increased load bearing capability.

Committee: Tarun Goswami DSc (Advisor); Pratik Parikh PhD (Committee Member); David Reynolds PhD (Committee Member) Subjects: Biomedical Research; Engineering

MS, University of Cincinnati, 2011, Engineering and Applied Science: Mechanical Engineering

Scoliosis is a musculoskeletal abnormality causing complex three dimensional curvatures in the spine. Current surgical treatments for this adolescent spinal deformity are successful but invasive. Potential new treatments that are less invasive are being developed based on altering growth by mechanically redistributing stresses across the vertebral growth plates. In the literature, in vivo and in vitro tests have shown biomechanical changes in the disc and growth plates due to insertion of staple like implants used in these new methods. In order to understand the biomechanics behind these potential new methods, a nonlinear finite element analysis (FEA) is performed and various biomechanical properties of the spinal segment with and without the implant are determined A three-dimensional FE model of T7-T8 motion segment was developed from a CT scan of a porcine spine and imported to ABAQUS (an FEA software). Various material properties and contact interactions were used from the literature in determining the model that best predicted the available experimental load-displacement curve and the compressive properties of the disc. Bending loads were applied to this FE model to determine the reduction in the motion of the spinal segment. Sensitivity of the implant features were examined against the compressive properties of the disc. Mechanobiological growth models have been partially developed to study various biomechanical factors causing deformities in spine. This available model was utilized in understanding how growth in a normal spine could be influenced due to the presence of these implants.

Committee: Yijun Liu PhD (Committee Chair); Donita Bylski-Austrow PhD (Committee Member); Kumar Vemaganti PhD (Committee Member) Subjects: Mechanical Engineering

MS, University of Cincinnati, 2007, Engineering : Industrial Engineering

Background Lower back pain continues to be a major occupational health problem. Therefore, continual refinement of workplace exposure assessment tools is fundamental to LBP prevention at the pre-injury stage and return-to-work at the post-injury stage. Objective The primary objectives are: (a) to conduct a systematic review and critical appraisal of the published literature on 3-D dynamic biomechanical models with reference to workplace applications; and (b) to present the theoretical development of a general-purpose 3-dynamic biomechanical for lifting and lowering activities Methods The study objectives were achieved in few work tasks that are electronic search of peer-reviewed articles on the subject, development of a biomechanical quality appraisal instrument, critical appraisal of the identified articles, and a complete documentation of the model development methods. Results In the first part, eight three-dimensional dynamic models were identified from the scientific literature. The quality appraisal showed that researchers paid more attention to model structure than model validation. In the second part, the paper describes at length the elements of a 3-D biomechanical model. Concluding Remarks Given the increasing importance of biomechanical exposure assessment in public health, it is highly recommended that a rigorous approach should be pursued in the quality of reporting and study execution of biomechanical models. The 3-D biomechanical model was outlined and will be validated in future research. Significance Increased attention to the quality of reporting and study execution of dynamic biomechanical models will allow the generation of best practices designed to achieve and sustain improved healthy settings at work and during leisure activities.

Committee: Dr. Ashraf Genaidy (Advisor) Subjects: Engineering, Industrial

MS, University of Cincinnati, 2005, Engineering : Mechanical Engineering

Objective: The objective of this research work is to develop a biomechanical model of the upper extremities and perform its kinematic analysis, concentrating mainly on the geometry and motion at the shoulder joint. Rationale for the Research: The prediction of the location of shoulder joint center plays a key role in the analysis of upper extremity movement especially with respect to the shoulder joint. Methods: Various methods for determining the shoulder joint center have been examined along with different methods to procure the joint angles. Based on this research, the prediction of the shoulder joint center has been done using two landmarks on the scapula and the Joint Coordinate System (JCS) method has been used define the angles especially at the shoulder. Procuring angles through methods utilizing direction cosines and Euler parameters have also been considered. In addition to this, defining the coordinate system for Thorax in five different ways and its effect on the joint angles has been examined. The coordinate system where one of the axes passes through the Sternum was finally adopted. These parameters were tested in a pilot study based on plyometrics, conducted at the Human Performance Laboratory at Cincinnati Children's Sports Medicine Biodynamics Center. Results: The results of the current pilot study indicate that the shoulder angles procured through the predicted shoulder center represented the motion that took place to a good extent. Differences exist for the angles obtained through the JCS method and other methods. Usage of a particular coordinate system for thorax also played a role in the angles outputted. Conclusion: The major emphasis of the current study is to have an upper extremity model, tested and tried, with different means of defining the shoulder center, coordinate system for thorax and procuring of joint angles. Validation of this model is essential to make further improvements and tender its usage for clinical purposes.

Committee: Dr. Ronald Huston (Advisor) Subjects: Engineering, Mechanical

MS, University of Cincinnati, 2004, Engineering : Industrial Engineering

Hypotheses: 1)Increased weight without posture adaptation will increase strength requirements measured by percent capable values in joint moment strengths. 2)The Recommended Weight Limit predicted by the NIOSH lifting equation does not guarantee that the L5/S1 compression force stays below the 3400 N recommended maximum for obese individuals in certain lifting postures. Methods: Data was input for a series of lifting postures. The percent capable at the ankle, knee, hip, torso, shoulder, and elbow as well as the compression force at the L5/S1 vertebrae were recorded for a variety of body weights and hand loads. Results: The results of the current pilot study indicate a relationship between increased body mass and a decrease in percent capable values. The study also demonstrates that for certain obese individuals, the NIOSH Revised Lifting Equation does not limit L5-S1 compression forces to below the 3400 N recommended threshold.

Committee: Dr. Woojin Park (Advisor) Subjects: Engineering, Industrial

Master of Science, The Ohio State University, 2012, Mechanical Engineering

Cartilage injuries are increasingly common among Americans, with an estimated 900,000 articular cartilage injuries diagnosed each year. While the natural history of focal cartilage defects is not fully understood, focal cartilage defects may develop due to large forces transmitted through the junction of uncalcified and calcified layers of cartilage. It is believed that cartilage degeneration and defect progression is multifactorial. While there are many important factors in sustaining cartilage health, we aim to examine the effects of the meniscus, loading, articular surface continuity, and local bone geometry. We first sought to identify how the meniscus influences contact force and area at 10 MPa in the medial and lateral condyles. We created defects in the femoral condyle of 20 porcine knees, and statically loaded that condyle in full extension to 10 MPa. We measured the force required to reach 10 MPa and resultant contact area at 10 MPa. We then performed a two-way analysis of variance and found that the presence of the meniscus and remaining condyle ( p < 0.001 for each) had significant effects on the force required to reach 10 MPa, as well as a significant interaction between the two factors (p = 0.007). These findings suggest that the meniscus should be included in biomechanical testing. To determine the effects of applied pressure, condyle, and defect on chondrocyte viability, we obtained 96 porcine knees and mounted them in an Instron in full extension. 48 knees were tested on the medial condyle only, and the other 48 were loaded on the lateral condyle. In half of each group of 48, a defect was created. Each of these groups were divided equally into four groups and loaded to either 10, 12, 14, or 16 MPa. The distribution of cell death was measured via live/dead cell assay. The applied pressure had a significant (p < 0.001) effect on the depth of cell death in samples with no defect. Both pressure level (p < 0.001) and condyle (p = 0.016) had significant ef (open full item for complete abstract)

Committee: Robert Siston PhD (Advisor); David Flanigan MD (Committee Member); Rebecca Dupaix PhD (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research; Mechanical Engineering