Biomedical Engineering and Bioengineering Commons^™

Comparison Of Brain Activity In The Prefrontal Cortex During Digit Span Task Between Student Veterans With Post Traumatic Stress Disorder And Controls Using Functional Near Infrared Spectroscopy, Bejoy Mathai

Bioengineering Theses - Archive

Near Infrared Spectroscopy (NIRS) is an optical non-invasive imaging technique which makes use of infrared light at particular wavelengths to measure the changes in concentrations of oxygenated blood haemoglobin (HbO) as well as the deoxygenated blood haemoglobin (HbR). Making use of this technique to acquire measurements during different functional activities subcategorises it into the novel and fast developing field of Functional Near Infrared Spectroscopy (fNIRS). In my study I have made use of this novel imaging technique to study the pre-frontal cortex while the subject performs the functional task of digit span task consisting of the forward digit span and …

Nanosecond Pulsed Electric Field Induced Cytoskeleton, Nuclear Membrane And Telomere Damage Adversely Impact Cell Survival, Michael W. Stacey, P. Fox, S. Buescher, Juergen F. Kolb

Bioelectrics Publications

We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and …

Modeling And Quantitative Analysis Of White Matter Fiber Tracts In Diffusion Tensor Imaging, Xuwei Liang

University of Kentucky Doctoral Dissertations

Diffusion tensor imaging (DTI) is a structural magnetic resonance imaging (MRI) technique to record incoherent motion of water molecules and has been used to detect micro structural white matter alterations in clinical studies to explore certain brain disorders. A variety of DTI based techniques for detecting brain disorders and facilitating clinical group analysis have been developed in the past few years. However, there are two crucial issues that have great impacts on the performance of those algorithms. One is that brain neural pathways appear in complicated 3D structures which are inappropriate and inaccurate to be approximated by simple 2D structures, …

Neurorehabilitation Of The Hand Using The Cybergrasp[Tm] And Mirror Image, Amy Frances Boos

Theses

In recent years, researchers have explored the use of a mirror image as a means of rehabilitation for individuals suffering from hemiparesis. Through neuroimaging and functional testing, neurological improvement has been demonstrated in those that engage in mirror therapy. Bilateral training, or simultaneous movement of both sides of the body, has also been studied as a treatment method to improve function after cerebral vascular accident. The development of robotic systems to assist movement of the human body has played a major role in the fabrication of bilateral training devices.

In this experiment, the CyberGrasp™ robotic exoskeleton was used to assist …

Role Of Hydrodynamic Behavior Of Dna Molecules In Dielectrophoretic Polarization Under The Action Of An Electric Field, Hui Zhao

Mechanical Engineering Faculty Research

A continuum model is developed to predict the dielectrophoretic polarizability of coiled DNA molecules under the action of an alternating current electric field. The model approximates the coiled DNA molecule as a charged porous spherical particle. The model explains the discrepancies among scaling laws of polarizability of different-sized DNA molecules with contour length and such discrepancies are attributed to different hydrodynamic behavior. With zero or one fitting parameter, theoretical predictions are in good agreement with various experimental data, even though in experiments there are some uncertainties in regard to certain parameters.

Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Pain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio-fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six-degree-of-freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high-resolution digital camera system. After establishing a neutral position, …

A Multi-Species Analysis Of Biomechanical Responses Of The Head To A Shock Wave, Richard Bolander

Wayne State University Dissertations

Shock wave induced brain injury remains a field of research that has great consequences for the rehabilitation of soldiers and civilians that are exposed to an explosion. As such, for the research to be successful in developing strategies to mitigate the effects of these injuries, appropriate research methods need to be developed. Animal models are currently employed to understand the brain's response to a shock wave exposure. Unfortunately no criteria have been established that indicates in what way the mechanical inputs that the cells in an animal's brain are subjected to are similar to a human. The purpose of this …

Supercritical Carbon Dioxide-Processed Resorbable Polymer Nanocomposites For Bone Graft Substitute Applications, Kevin Baker

Wayne State University Dissertations

Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the …

Computational Simulation Of Skull Fracture Patterns In Pediatric Subjects Using A Porcine Model, Christina Devito Wagner

Wayne State University Dissertations

In cases of suspected child abuse with skeletal trauma, it is often the role of the injury biomechanist, forensic pathologist, clinical radiologist, and forensic anthropologist to determine the mechanism of injury when the child victims cannot speak for themselves. This is a challenging task, especially for the head, as comprehensive biomechanical data on skull fracture in infants and children do not currently exist, and frequently the determination regarding cause of injury is based on anecdotal evidence from the medical literature and unsubstantiated eyewitness accounts. The current process may result in unreliable autopsy interpretation and miscarriages of justice due to a …

Perforation Of Arterial Tissue Using Kilohertz Frequency Ultrasound Delivered Via Wire Waveguides, Mark Wylie, Garrett Mcguinness, Graham Gavin

Conference Papers

An emerging technology proposes the use of low frequency-high power ultrasound transmitted via wire waveguides for the disruption and ablation of atherosclerotic lesions, more specifically advanced fibrous or calcified plaques such as chronic total occlusions (CTO). This energy delivery selectively ablates rigid diseased tissue by means of direct mechanical contact, cavitation and other forces generated by the intense dynamic pressure fields generated.

The first clinical device using this energy delivery was granted FDA approval in 2007 [1] for the ablation of CTOs and most research to date has focused on ablation and disruption of hard, fibrous or calcified tissues [2]. …

Locating And Extracting Acoustic And Neural Signals, Na Zhu

Wayne State University Dissertations

This dissertation presents innovate methodologies for locating, extracting, and separating multiple incoherent sound sources in three-dimensional (3D) space; and applications of the time reversal (TR) algorithm to pinpoint the hyper active neural activities inside the brain auditory structure that are correlated to the tinnitus pathology. Specifically, an acoustic modeling based method is developed for locating arbitrary and incoherent sound sources in 3D space in real time by using a minimal number of microphones, and the Point Source Separation (PSS) method is developed for extracting target signals from directly measured mixed signals. Combining these two approaches leads to a novel technology …

Issues On Clean Diesel Combustion Technology Using Supercritical Fluids: Thermophysical Properties And Thermal Stability Of Diesel Fuel, Ronghong Lin

Biomedical and Chemical Engineering - Dissertations

The clean diesel combustion technology using supercritical fluids is aimed to both improve fuel economy and reduce harmful emissions. This novel process involves preparation, injection and combustion of supercritical fuel/diluents mixtures. Design and development of this new process require a deep understanding of fuel properties. The current study has attempted to address three fuel property related issues: fuel surrogates, diffusivity and thermal stability.

Fuel surrogates are often used in engine research to mimic real fuel properties. In this work, ten diesel fuel surrogates were investigated, and the ability of these surrogates to predict diesel fuel properties was evaluated. It was …

Exploring The Potential Of Inkjet Printing For The Fabrication Of Tissue Test Systems, Vidya Seshadri

All Theses

Animal models and two-dimensional assays involved in drug testing, vaccine development and basic scientific discovery are not an accurate representation of the human body; hence there is a need to develop new bench top methodologies which are better suited to yield information about in vivo behavior. There is a paucity of reliable in vitro-derived information regarding the reasons for the cause and progression of diseases. These concerns have lead to the development of three-dimensional systems which can facilitate improved understanding of disease etiology and also can bridge the path to the clinic.
The long term goal, beyond the scope of …

Energy Deposition In The Breast During Ct Scanning: Quantification And Implications For Dose Reduction, Franco Rupcich, Iacovos Kyprianou, Andreu Badal, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Studies suggest that dose to the breast leads to a higher lifetime attributable cancer incidence risk from a chest CT scan for women compared to men. Numerous methods have been proposed for reducing dose to the breast during CT scanning, including bismuth shielding, tube current modulation, partial-angular scanning, and reduced kVp. These methods differ in how they alter the spectrum and fluence across projection angle. This study used Monte Carlo CT simulations of a voxelized female phantom to investigate the energy (dose) deposition in the breast as a function of both photon energy and projection angle. The resulting dose deposition …

Effects Of Acute Rho Kinase Inhibition On Chronic Hypoxia-Induced Changes In Proximal And Distal Pulmonary Arterial Structure And Function, Rebecca R. Vanderpool, Ah Ram Kim, Robert C. Molthen, Naomi Chesler

Biomedical Engineering Faculty Research and Publications

Hypoxic pulmonary hypertension (HPH) is initially a disease of the small pulmonary arteries. Its severity is usually quantified by pulmonary vascular resistance (PVR). Acute Rho kinase inhibition has been found to reduce PVR toward control values in animal models, suggesting that persistent pulmonary vasoconstriction is the dominant mechanism for increased PVR. However, HPH may also cause proximal arterial changes, which are relevant to right ventricular (RV) afterload. RV afterload can be quantified by pulmonary vascular impedance, which is obtained via spectral analysis of pulsatile pressure-flow relationships. To determine the effects of HPH independent of persistent pulmonary vasoconstriction in proximal and …

Multimodality Imaging Of Abnormal Vascular Perfusion And Morphology In Preclinical 9l Gliosarcoma Model, Moses M. Darpolor, Robert C. Molthen, Kathleen M. Schmainda

Biomedical Engineering Faculty Research and Publications

This study demonstrates that a dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI) perfusion parameter may indicate vascular abnormality in a brain tumor model and reflects an effect of dexamethasone treatment. In addition, X-ray computed tomography (CT) measurements of vascular tortuosity and tissue markers of vascular morphology were performed to investigate the underpinnings of tumor response to dexamethasone.

Reorganization Of Finger Coordination Patterns During Adaptation To Rotation And Scaling Of A Newly Learned Sensorimotor Transformation, Xiaolin Liu, Kristine M. Mosier, Ferdinando A. Mussa-Ivaldi, Maura Casadio, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined how people organize redundant kinematic control variables (finger joint configurations) while learning to make goal-directed movements of a virtual object (a cursor) within a low-dimensional task space (a computer screen). Subjects participated in three experiments performed on separate days. Learning progressed rapidly on day 1, resulting in reduced target capture error and increased cursor trajectory linearity. On days 2 and 3, one group of subjects adapted to a rotation of the nominal map, imposed either stepwise or randomly over trials. Another group experienced a scaling distortion. We report two findings. First, adaptation rates and memory-dependent motor command updating …

Visual And Proprioceptive Contributions To Compensatory And Pursuit Tracking Movements In Humans, Megan L. Heenan, Robert A. Scheidt, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

An ongoing debate in the field of motor control considers how the brain uses sensory information to guide the formation of motor commands to regulate movement accuracy. Recent research has shown that the brain may use visual and proprioceptive information differently for stabilization of limb posture (compensatory movements) and for controlling goal-directed limb trajectory (pursuit movements). Using a series of five experiments and linear systems identification techniques, we modeled and estimated the sensorimotor control parameters that characterize the human motor response to kinematic performance errors during continuous compensatory and pursuit tracking tasks. Our findings further support the idea that pursuit …

Quantifying Mitochondrial And Plasma Membrane Potentials In Intact Pulmonary Arterial Endothelial Cells Based On Extracellular Disposition Of Rhodamine Dyes, Zhuohui Gan, Said H. Audi, Robert D. Bongard, Kathryn M. Gauthier, Marilyn P. Merker

Biomedical Engineering Faculty Research and Publications

Our goal was to quantify mitochondrial and plasma potential (Δψ_m and Δψ_p) based on the disposition of rhodamine 123 (R123) or tetramethylrhodamine ethyl ester (TMRE) in the medium surrounding pulmonary endothelial cells. Dyes were added to the medium, and their concentrations in extracellular medium ([R_e]) were measured over time. R123 [R_e] fell from 10 nM to 6.6 ± 0.1 (SE) nM over 120 min. TMRE [R_e] fell from 20 nM to a steady state of 4.9 ± 0.4 nM after ∼30 min. Protonophore or high K⁺ concentration ([K⁺]), …

Instrument Independent Diffuse Reflectance Spectroscopy, Bing Yu, Henry L. Fu, Nirmala Ramanujam

Biomedical Engineering Faculty Research and Publications

Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm …