Biomedical Engineering and Bioengineering Commons^™

A Left Ventricular Motion Phantom For Cardiac Magnetic Resonance Imaging, Mehmet Ersoy

ETD Archive

The mammalian left ventricle (LV) has two distinct motion patterns: wall thickening and rotation. The purpose of this study was to design and build a low-cost, non-ferromagnetic LV motion phantom, for use with cardiac magnetic resonance imaging (MRI), that is able to produce physiologically realistic LV wall thickening and rotation. Cardiac MRI is continuously expanding its range of techniques with new pulse sequences, including new tissue tagging techniques which allow intra-myocardial deformation to be visualized. An essential step in the development of new cardiac MRI techniques is validating their performance in the presence of motion. MRI-compatible dynamic motion phantoms are …

Assessment Of Circumferential Myocardial Function Using Radial Tagged Mri, Yujaung Kim

ETD Archive

The extent of myocardial abnormalities is related to cardiac disease. The assessment of myocardial function of the left ventricular (LV) described by the LV myocardial deformation plays an important role to understand the effects of cardiovascular disease and therapeutic interventions on LV motion. Cardiac magnetic resonance imaging (CMR) is widely agreed as the most accurate noninvasive imaging modality for the assessment of left ventricular (LV) function. In addition, myocardial-tagging technique can track the myocardial deformation by labeling specific regions. Although the grid tagging is popular in cardiac research use, it has not been adopted into routine clinical examination with unreliable …

A Concept For Direct Control Of Rotary Blood Pump Speed By Inlet Pressure, Ibrahim Seven

ETD Archive

Heart failure remains a major health problem for the world. Heart transplantation is the most effective treatment for end stage heart failure. A major problem with heart transplantation is finding adequate numbers of appropriate donors. The lack of donor numbers in the world creates a significant clinical need for blood pumping devices. The ability of ventricular assist devices to relieve the consequences of less than terminal heart failure further creates a need for assist therapy. Current new ventricular assist devices are built around continuous flow technology. These nonpulsatile assist devices have had major clinical success in relieving symptoms and increasing …

Effect Of Step Change In Growth Speed During Directional Solidification On Array Morphology Of Al-7 Wt Si Alloy, Swapna Pakiru

ETD Archive

No abstract provided.

Measurement Of White Matter Structure Changes In Amyotrophic Lateral Sclerosis Using Fractal Analysis, Zao Liu

ETD Archive

Amyotrophic lateral sclerosis (ALS) is recognized as a motor neuron disorder affecting the structure and function of the brain and neuromuscular system. Very little is known, however, that the nervous system degeneration is dependent on disease phenotypes of ALS. The purpose of this study was to determine the degree of brain white matter (WM) structure degeneration in four ALS patient groups characterized by their clinical signs and neuroimaging measurements. Fractal dimension (FD) of three-dimensional (3D) brain WM images was quantitatively analyzed to evaluate the WM structural complexity, including complexity levels of the WM skeleton, surface and general structures in ALS …

An Assessment Of The Accuracy Of Magnetic Resonance Phase Velocity Mapping In Turbulent Flow Through Orifices, Sahitya Pidaparthi

ETD Archive

Magnetic resonance phase velocity mapping (MRPVM) is an established clinical technique to measure blood flow. The acquired information can be used to diagnose a variety of cardiovascular disease. One of the main limitations of MRPVM is that it cannot quantify the flow under turbulent flow conditions. Such conditions develop in certain cases such as in heart valve stenosis and arterial stenosis. Specifically, heart valve stenosis is a serious disease in which the valve does not open as much as necessary for blood to pass through. As a result, the heart has to overwork to overcome the increased resistance. If untreated, …

Reinforced Chitosan-Based Heart Valve Scaffold And Utility Of Bone Marrow-Derived Mesenchymal Stem Cells For Cardiovascular Tissue Engineering, Mohammad Z. Albanna

Wayne State University Dissertations

Recent research has demonstrated a strong correlation between the differentiation profile of mesenchymal stem cells (MSCs) and scaffold stiffness. Chitosan is being widely studied for tissue engineering applications due to its biocompatibility and biodegradability. However, its use in load-bearing applications is limited due to moderate to low mechanical properties. In this study, we investigated the effectiveness of a fiber reinforcement method for enhancing the mechanical properties of chitosan scaffolds. Chitosan fibers were fabricated using a solution extrusion and neutralization method and incorporated into porous chitosan scaffolds. The effects of different fiber/scaffold mass ratios, fiber mechanical properties and fiber lengths on …

An Investigation Of The Biomechanical Response From Shock Wave Loading To The Head, Alessandra Dal Cengio Leonardi

Wayne State University Dissertations

There is a pressing need for a comprehensive explanation of the mechanism of brain injury after exposure to blast and several hypotheses have been suggested. The focus of this research was to investigate one of the hypotheses for primary brain injury due to blast: multimodal skull flexure. The significance of this research is twofold. First, resolution of the mode of energy transfer and of the induced stresses within the skull-brain system will allow for creations of mitigation/protective techniques/equipment, as well as design of experiments investigating live-cell response using more reliable physical models. Second, the data obtained experimentally will be available …

Finite Element Reconstruction Of Real World Aortic Injury In Near-Side Lateral Automotive Crashes With Conceptual Countermeasures, Aditya Neelakanta Belwadi

Wayne State University Dissertations

Traumatic rupture of the aorta (TRA) remains the second most common cause of death associated with motor vehicle crashes after brain injury. On an average, nearly 8,000 people die annually in the United States due to blunt injury to the aorta. It is observed that more than 80% of occupants who suffer an aortic injury die at the scene due to exsanguination into the chest. With the advent of more accurate and established human body finite element (FE) models, FE crash reconstruction methods may become a valuable tool when assessing crash scenarios and occupant injury mechanisms.

The current study is …

Differences Between Adult And Pediatric Neck Muscle Stress Due Muscle Recruitment Patterns, Renee Dawson

Wayne State University Dissertations

In 2000 and 2001 an estimated 150,000 children between the ages of 0 and 8 years old were injured or killed in a motor vehicle accident. Despite advances in child safety restraints and vehicle restraints, automobile accidents remain the primary cause of death for children in the 0-8 year old age group. In 1982, in an attempt to reduce the number of deaths and injuries of children, the first child crash test dummy was developed. The responses of this dummy were scaled from the adult response data based on the assumption that children were similar to adults both anatomically and …

Micromotion And Scarring Do Not Contribute To Failure Of Regenerative Peripheral Neural Interfacing, Nivedita Khobragade

Bioengineering Theses - Archive

Neuroprosthetics facilitate amputees with motor function restoration by interfacing nervous system with artificial limb and enabling control of the prosthetic device by volitional thought. Though such neurointerfacing provides dexterity nearly mimicking natural limb agility, the clinical viability of such prosthetics is limited by the lack of long-term reliability. In central nervous system, these implants fail due to foreign body reaction and glial scar formation around the implant. The cause of decrease in active sites of interfacing in peripheral nervous system, which is less invasive than central nervous system implantation, has not been established. Recently an open architecture, regenerative peripheral neural …

Methodology Of Citrate-Based Biomaterial Development And Application, M. Richard Tran

Bioengineering Dissertations - Archive

Biomaterials play central roles in modern strategies of regenerative medicine and tissue engineering. Attempts to find tissue-engineered solutions to cure various injuries or diseases have led to an enormous increase in the number of polymeric biomaterials over the past decade. The breadth of new materials arises from the multiplicity of anatomical locations, cell types, and mode of application, which all place application-specific requirements on the biomaterial. Unfortunately, many of the currently available biodegradable polymers are limited in their versatility to meet the wide range of requirements for tissue engineering. Therefore, a methodology of biomaterial development, which is able to address …

Investigation Of Neural Correlates Between Perception Of Pain And Hemodynamic Response Measured In The Pre-Frontal Cortex Using Functional Near Infra-Red Spectroscopy, Venkatagiri Krishnamurthy

Bioengineering Dissertations - Archive

Perception of pain is multi-dimensional, comprising three major psychological dimensions: sensory-discriminative, motivational-affective and cognitive-evaluative. This dissertation study investigates the cognitive evaluation of pain, by acquiring functional Near Infra-Red Spectroscopic (fNIRS) measurements from the prefrontal cortex (PFC) areas, during mechanical and thermal pain stimulation induced on the subject's volar forearm. Clustered-wise analysis on the oxy-hemoglobin (HbO) response from specific PFC areas was followed by categorizing the resulting HbO response into early (0.1-12sec) and late (12.1-25sec) phases. For each respective phase, regression analysis was carried between the HbO-derived parameters and behaviorally measured pain rating. The major findings of this study include: (1) …

Novel Applications Of Compressed Sensing To Magnetic Resonance Imaging And Spectroscopy, Sairam Geethanath

Bioengineering Dissertations - Archive

In this work, three novel applications of compressed sensing to MRI have been developed and implemented which accomplish reduction in acquisition time, thereby also enabling increased spatial and/or temporal resolution. The first application is for reducing the acquisition time of conventional 1H magnetic resonance spectroscopic imaging (MRSI), which requires alongeracquisition time than conventional MRI. The implementation involved exploiting the inherent sparsity of the MRSI data in the wavelet domain by the use of Daubechies wavelet. This was demonstrated on an in vitro phantom, 6 healthy human brain MRSI data sets, 2 brain and prostate cancer data sets. The reconstructions were …

Novel ¹H Mr Probes To Interrogate The Tumor Microenvironment, Praveen Kumar Gulaka

Bioengineering Dissertations - Archive

The term "tumor microenvironment" usually refers to the description of the physiological and metabolic conditions within solid tumors (primary or metastatic), and is significantly different from that of normal tissues. Assessment of factors like pH, tissue oxygen tension (pO2) and gene expression in the tumor microenvironment and the ability to image them in vivo can provide useful prognostic information. For example, hypoxia (low pO2), typically distributed heterogeneously in solid tumors, is known to affect both radiation sensitivity and the development of metastases thereby influencing the response to treatment. This dissertation research focuses on the evaluation of novel probes to interrogate …

Wireless Closed-Loop Feedback Systems For Automatic Detection And Suppression Of Nociceptive Signals, Aydin Farajidavar

Bioengineering Dissertations - Archive

Chronic pain is an important public health issue. Several approaches have been implemented for management of chronic pain, including surgical implantation of neurostimulators. Neurostimulators have been used in clinics for spinal cord implantation and they have been suitable for relieving certain types of pains, such as neuropathic pain in leg or arm, complex regional pain, and refractory angina. The stimulation at spinal cord has little relieving effects on syndromes such as facial pain, cluster headache, phantom limb pain, and post stroke pain. For treating such syndromes, electrical stimulation of deep brain structures such as thalamic nuclei (e.g. ventroposterolateral (VPL) or …

Cell Specific Guidance Of Nerve And Vascular Regeneration Through Sustained Growth Factor Release, Parisa Lotfi

Bioengineering Dissertations - Archive

Regenerative peripheral nerve interfaces have been proposed as viable alternatives for the natural control of robotic prosthetic devices. However, sensory and motor axons at the neural interface are of mixed submodality types, which difficult the specific recording from motor axons and the eliciting of precise sensory modalities through selective stimulation. Here we evaluated the possibility of using type-specific neurotrophins to preferentially entice the regeneration of defined axonal populations from injured peripheral nerves. Segregation of mixed sensory fibers from dorsal root ganglion neurons was evaluated in vivo by compartmentalized diffusion delivery of nerve growth factor (NGF) and neurotrophin-3 (NT-3), to preferentially …

Photosynthetically Active Protoplasts For Power Scavenging, Absorbance And Optical Density Analysis, Ahmed Shahid

Bioengineering Theses - Archive

Plants and photosynthetic bacteria hold protein molecular complexes that can efficiently harvest photons. This paper presents fundamental studies to harness photochemical activities by converting photonic energy into electrical energy. The electrical behavior of protoplast extracted from Arabidopsis plants was characterized in the presence and absence of light. The photo-induced reactions of photosynthesis were measured using a patch clamp measurement system at a constant voltage. This research also reports the absorbance and optical density measurements showing very large bandwidth for extracted protoplasts. The optical measurements were performed on the protoplast Arabidopsis and showed absorption bands at a number of wavelengths. The …

An Investigation Of Support Vector Machine Classifier In Detecting Nocturnal Airway Obstruction From Spontaneous Heart Rate Combined With Ecg Morphology Changes, Harshan Ravi

Bioengineering Theses - Archive

Sleep apnea is a sleep disordered breathing resulting from limitation or cessation to breathing for 10 or more seconds. The prevalence of sleep apnea has increased exponentially in the past decade. The increase in epidemic in sleep apnea is associated with increase in the cases of obesity. It is estimated that 12-18 million of American adults suffer from sleep apnea, which is a sizable sector of the adult population. Sleep apnea is risk factor for hypertension, type II diabetes, and congestive heart failure. Sleep apnea may go undiagnosed for a long period of time after its onset due to complexity …

Design, Fabrication, And Testing Of An Electrospinning Apparatus For The Deposition Of Pmma Polymer For Biomedical Applications, Harsha Malshe

Inquiry: The University of Arkansas Undergraduate Research Journal

This paper describes the successful design and fabrication of a deposition system for synthesis and assembly of nanoscale and submicron sized fibers of poly(methylmethacrylate)(PMMA) polymer. To optimize the electrospinning deposition process, the distance between the needle and the electrically grounded substrate, the applied voltage, and the concentration of PMMA polymer in the solution were varied. PMMA fibers as small as 500 nanometers were observed using scanning electron microscopy (SEM). The chemical signature of PMMA was confirmed for best quality and retention of chemistry using Fourier Transformed Infrared spectroscopy (FT-IR). PMMA is a biocompatible polymer, and nanofibers of PMMA are key …