With balance assessment being essential to the prediction of fall risk and detection and assessment of motor disorders, increasing clinical accessibility to objective balance metrics is essential. Work has been done validating center of mass (COM) acceleration metrics against well regarded force plate center of pressure (COP) position standards for mobile device data acquisition systems, but most research is restricted to devices being close to the COM or strapped in a harness configuration. Through the use of rigid body kinematics and the inverted pendulum model, this study develops novel methodology for calculating COM acceleration using mobile devices in arbitrary positions, as well as a novel approach to validation through direct comparison of COP position predictions to force plate measurements. Validation of this methodology included comparison of smartphone and force plate results for COM accelerations and COP positions. Results showed good analysis performance for both approaches during subject intentional swaying, but results were limited in cases of little motion where good balance was observed.

<p dir="ltr">The focus is on the complex nature of primary blast injury (PBI) and employs advanced simulation techniques to model the physiological impacts using a TBI-on-a-chip system. This study involves a two-way Fluid-Structure Interaction (FSI) model in ANSYS, coupling Transient Structural and Fluent modules to simulate the effects of a blast wave on brain tissue. The research explores the creation and validation of boundary conditions, such as fixed support and varying strain rates, to ensure the reliability of the experimental setup. Key findings include the non-uniform distribution of strain, which has significant implications for understanding injury mechanisms and inflammatory marker analysis. The project also provides a detailed workflow for FSI simulations, highlighting the advantages of uniform mechanical loading and its impact on experimental accuracy.</p>

<p dir="ltr">Murine, or small rodent, models can provide valuable and translatable insights into human pathophysiology. Specifically, we are looking to combine murine models and high-frequency ultrasound to non-invasively investigate microrobot drug delivery systems, cardiac effects of lactation on the mother during postpartum, and cardiac remodeling due to the combination of pregnancy and hypertension.</p><p dir="ltr">Currently, we are looking at the applications of microrobots within the colon to provide targeted treatment for patients suffering from inflammatory bowel disease (IBD). IBD is an overarching term encompassing chronic inflammation of the digestive tract tissue. The standard treatment of IBD includes oral and injectable treatments depending on disease severity. The drawbacks of these therapeutics are the associated systemic toxicity, non-specific treatment allocation, and degradation of the treatment in proximal portions of the gastrointestinal (GI) system. The goal of this research is to use an external magnetic torque to cause the microrobots to tumble to targeted areas of inflammation and release a drug payload. Retroactive locomotion of these microrobots can avoid degradation in the proximal GI tract. Therefore, these microrobots need a smaller drug payload to provide the same efficacy as traditional treatments.</p><p dir="ltr">The cardiovascular system adapts to meet the growing physiological demands of pregnancy. Although this change has been greatly studied, it is unclear if this change in shape and function returns to prepregnant values during postpartum. Previous research has also shown that lactation affects the mother’s hemodynamics during postpartum, but its impact on cardiac morphology is still not completely understood. To study this further, we longitudinally tracked cardiovascular changes using ultrasound and blood pressure measurements in C57BL6/J mice during pregnancy and postpartum that were either lactating or not.</p><p dir="ltr">Chronic hypertension affects approximately 1 in 20 pregnancies and its prevalence in pregnancies continues to increase. The maternal cardiovascular system goes through dynamic changes during pregnancy to meet the demands of perfusing the gestation, especially during the exponential growth seen later in pregnancy. Studies with female C57BL6/J mice demonstrate comparable cardiovascular changes during pregnancy to those observed in humans. Additionally, a study using rats showed the cardioprotective properties of pregnancy against angiotensin II-induced fibrosis. The objective of this study is to characterize non-invasive cardiac remodeling in a small animal model of hypertensive disorders in pregnancy. We used a combination of ultrasound imaging and noninvasive blood pressure measurements to longitudinally monitor the physiological adaptations that occur during pregnancy with superimposed hypertension.</p>

<p dir="ltr">Diabetes has become an international health crisis with type 2 diabetes composing the majority of cases. Along with a variety of other systemic effects, type 2 diabetes increases fracture risk. This aspect of type 2 diabetes has become a topic of interest in preclinical research and has been investigated using rodent models of type 2 diabetes. Of these models, the Yellow Kuo Kondo (KK-A^y) mouse model has shown promise as an obese model of type 2 diabetes. In the KK-A^y model, mice heterozygous for a mutation in the agouti gene (A^y) are treated as an obese model of type 2 diabetes. Those that are homozygous (no mutation) are treated as non-diabetic, obese controls. While this model has been indicated to be non-diet dependent, recent data has revealed the efficacy of this model may be reliant on diet. Following approval from the Indiana University-Purdue University at Indianapolis School of Science Institutional Animal Care and Use Committee, mice of each sex and genotype were placed on separate diets. Half on a standard chow diet and the other half on a diet recommended by Jackson Laboratory for this strain. Animals were aged to 16 weeks of age with blood glucose and body weight monitored every other week. Animals were then sacrificed to collect whole blood, blood serum, the pancreas, bilateral tibiae, and bilateral femora. End-point metabolic impacts were assessed through hemoglobin A1c and serum insulin measures while skeletal measures were quantified using microcomputed tomography scanning and analysis. Through this research, it was determined diet did have a significant impact on the skeletal and metabolic phenotype associated with type 2 diabetes in the KK-A^ymodel. </p>

No / The ability of prisms to effectively dissipate contact stress at the surface will influence wear rates in teeth. The aim of this investigation was to begin to quantify the effect of prism orientation on surface stresses. Seven finite element models of enamel microstructure were created, each model differing in the angulation of prism orientation with regard to the wear surface. For validation purposes, the mechanical behavior of the model was compared with published experimental data. In order to test the enamel under lateral loads, a compressed food particle was dragged across the surface from the dentino-enamel junction (DEJ) towards the outer enamel surface (OES). Under these conditions, tensile stresses in the enamel model increased with increases in the coefficient of friction. More importantly, stresses were found to be lowest in models in which the prisms approach the surface at lower angles (i.e., more obliquely cut prisms), and highest when the prisms approached the surface at 60° (i.e., less obliquely cut). Finally, the direction of travel of the simulated food particle was reversed, allowing comparison of the difference in behavior between trailing and leading edge enamels (i.e., when the food particle was dragged either towards or away from the DEJ). Stresses at the trailing edge were usually lower than stresses at the leading edge. Taken together with what is known about prism orientation in primate teeth, such findings imply greater wear resistance at the intercuspal region and less wear resistance at the lateral enamel at midcrown. Such findings appear to be supported by archeological evidence.

Yes / There is a clinical need for novel graft materials for the repair of peripheral nerve defects. A decellularisation process has been developed for porcine peripheral nerves, yielding a material with potentially significant advantages over other devices currently being used clinically (such as autografts and nerve guidance conduits). Grafts derived from xenogeneic tissues should undergo sterilisation prior to clinical use. It has been reported that sterilisation methods may adversely affect the properties of decellularised tissues, and therefore potentially negatively impact on the ability to promote tissue regeneration. In this study, decellularised nerves were produced and sterilised by treatment with 0.1% (v/v) PAA, gamma radiation (25-28 kGy) or E Beam (33-37 kGy). The effect of sterilisation on the decellularised nerves was determined by cytotoxicity testing, histological staining, hydroxyproline assays, uniaxial tensile testing, antibody labelling for collagen type IV, laminin and fibronectin in the basal lamina, and differential scanning calorimetry. This study concluded that decellularised nerves retained biocompatibility following sterilisation. However, sterilisation affected the mechanical properties (PAA, gamma radiation), endoneurial structure and basement membrane composition (PAA) of decellularised nerves. No such alterations were observed following E Beam treatment, suggesting that this method may be preferable for the sterilisation of decellularised porcine peripheral nerves.

Šiame magistro darbe eksperimentiškai nustatomas biomechaniškai patikimesnis ir stipresnis raktikaulio ir mentės fiksavimas. Yra taikomi 3 skirtingi raktikaulio ir snapinės ataugos sujungimo būdai. Teorinėje dalyje išanalizuota petinio raktikaulio sąnario anatomija, traumos mechanizmas, traumų paplitimas. Apžvelgti raktikaulio ir mentės fiksavimo būdai, išanalizuoti labiausiai cituojami literatūroje biomechaniniai tyrimai, kuriuose tarpusavyje lyginami skirtingi gydymo būdai statinės ir dinaminės apkrovos aspektais. Eksperimentinėje dalyje suprojektuotas ir pagamintas stendas, kad būtų galima nustatyti biomechaniškai stipresnį ir patikimesnį raktikaulio ir snapinės ataugos sujungimą. Atlikti eksperimentiniai matavimai taikant 3 skirtingas fiksavimo metodikas. Atlikta rezultatų analizė ir apdorojimas, taikant statistikos metodus. Atlikus sistemos eksperimentinį tyrimą, pateiktos baigiamojo darbo išvados ir pasiūlymai. Darbo apimtis – 74 p. teksto be priedų, 46 pav., 4 lent., 69 bibliografiniai šaltiniai. / This Master degree thesis experimentally determined biomechanical more reliable and stronger clavicle and scapula fixation. There are 3 applicable different clavicle and coracoid process fixation techniques. Theoretical part is an analysis of acromioclavicular joint anatomy, injury mechanism, injury incidence. The clavicle and scapula fixation methods are reviewed, the analysis of the most cited literature in biomechanical studies is completed, in which different treatment methods are compared on the aspects of the static and dynamic load. On the experimental part the stand is designed and produced for the purpose of the establishment of a stronger and more reliable biomechanical clavicle and coracoid process fixation. Experimental measurements are performed using three different fixation techniques. The results are analyzed and treatment, using statistical methods. The conclusions and recommendations are given at the end of this work. The thesis consists of 74 p. text without appendixes, 46 pictures, 4 tables, 69 bibliographical entries.

Several surgically corrective procedures are considered to treat Adult Acquired Flatfoot Deformity (AAFD) patients, relieve pain, and restore function. Procedure selection is based on best practices and surgeon preference. Recent research created patient specific models of Adult Acquired Flatfoot Deformity (AAFD) to explore their predictive capabilities and examine effectiveness of the surgical procedure used to treat the deformity. The models’ behavior was governed solely by patient bodyweight, soft tissue constraints, and joint contact without the assumption of idealized joints. The current work expanded those models to determine if an alternate procedure would be more effective for the individual. These procedures included one hindfoot procedure, the Medializing Calcaneal Osteotomy (MCO), and one of three lateral column procedures: Evans osteotomy, Calcaneocuboid Distraction Arthrodesis (CCDA), Z osteotomy and the combination procedures MCO & Evans osteotomy, MCO & CCDA, and MCO & Z osteotomy all used in combination with a tendon transfer. The combination MCO & Evans and MCO & Z procedures were shown to provide the greatest amount of correction for both forefoot abduction and hindfoot valgus. However, these two procedures significantly increased the joint contact force, specifically at the calcaneocuboid joint, and ground reaction force along the lateral column. With exception to the lateral bands of the plantar fascia and middle spring ligament, the strain present in the plantar fascia, spring, and deltoid ligaments decreased after all procedures. The use of patient specific computational models provided the ability to investigate effects of alternate surgical corrections on restoring biomechanical function in flatfoot patients.

Heart failure is expected to ail over 8 million people in America by 2030 leaving many in need of cardiac replacement. To accommodate this large volume of people, ventricular assist devices (VADs) are necessary to provide mechanical circulatory support. Current VADs exhibit issues such as thrombosis and hemolysis caused by large local pressure drops and turbulent flow within the pump. Multiple disk centrifugal pumps (MDCPs) use shearing and centrifugal forces to produce laminar flow patterns and eliminate large pressure drops within the pump which greatly reduce risks that are in current VADs. The MDCP has a shaft drive system (SDS) that causes leakage between the motor and housing that when implanted can cause blood loss, infection, thrombosis and hemolysis. To eliminate these adverse effects, a magnetic external motor-driven system (MEMDS) was implemented. An efficiency study was performed to examine the efficacy of the MEMDS by comparing the hydraulic work of the MDCP to the power required to run the pump. This was done by measuring inlet and outlet pressures, outlet flow rate and input current at various input voltages and resistances. The results showed the MDCP could produce physiologic flow characteristics with a flow rate of 4.90 L/min and outlet pressure of 61.33 mmHg at an impeller speed of 989.79 rpm. Other VADs generate flow rates around 5 L/min at rotational speeds of 2400 rpm for centrifugal pumps and 12000 rpm for axial pumps. When compared to the SDS, the MEMDS exhibited similar efficiencies of 3.89% and 3.50% respectively. This study shows promise in the advancement of MDCP.

This research utilizes CFD to analyze blood flow through pathways representative of central shunts, commonly used as part of the Fontan procedure to treat cyanotic heart disease. In the first part of this research, a parametric study of steady, Newtonian blood flow through parabolic pathways was performed to demonstrate the effect that flow pathway curvature has on wall shear stress distribution and flow energy losses. In the second part, blood flow through two shunts obtained via biplane angiograms is simulated. Pressure boundary conditions were obtained via catheterization. Results showed that wall shear stresses were of sufficient magnitude to initiate platelet activation, a precursor for thrombus formation. Steady results utilizing time-averaged boundary conditions showed excellent agreement with the time-averaged results obtained from pulsatile simulations. For the points of interest in this research, namely wall shear stress distribution and flow energy loss, the Newtonian viscosity model was found to yield acceptable results.