Biomedical Engineering and Bioengineering Commons^™

The Advancement Of Bacterial Cellulose As A Bone And Vascular Scaffolds, Ryan Lee Hammonds

Doctoral Dissertations

Bacterial cellulose (BC) is a natural hydrogel made of nanofibers. This material has been used in commercial products, including wound dressings. BC can be modified and optimized for improved performance in multiple applications. This work will focus on producing and characterizing resorbable cellulose, a composite for bone applications, and a composite for a synthetic venous valve leaflet.

BC can be produced and modified to perform as a degradable tissue scaffold. This is achieved by an oxidation procedure after the initial production and purification of native BC. A material characterization of oxidized BC was performed to identify the changes in properties …

Analysis, Segmentation And Prediction Of Knee Cartilage Using Statistical Shape Models, Joseph Michael Johnson

Doctoral Dissertations

Osteoarthritis (OA) of the knee is one of the leading causes of chronic disability (along with the hip). Due to rising healthcare costs associated with OA, it is important to fully understand the disease and how it progresses in the knee. One symptom of knee OA is the degeneration of cartilage in the articulating knee. The cartilage pad plays a major role in painting the biomechanical picture of the knee. This work attempts to quantify the cartilage thickness of healthy male and female knees using statistical shape models (SSMs) for a deep knee bend activity. Additionally, novel cartilage segmentation from …

Reconstruction Of Patient-Specific Bone Models From X-Ray Radiography, Hatem Amin Abdel Fattah El Dakhakhni

Doctoral Dissertations

The availability of a patient‐specific bone model has become an increasingly invaluable addition to orthopedic case evaluation and planning [1]. Utilized within a wide range of specialized visualization and analysis tools, such models provide unprecedented wealth of bone shape information previously unattainable using traditional radiographic imaging [2]. In this work, a novel bone reconstruction method from two or more x‐ray images is described. This method is superior to previous attempts in terms of accuracy and repeatability. The new technique accurately models the radiological scene in a way that eliminates the need for expensive multi‐planar radiographic imaging systems. It is also …

Modeling And Control Of Nanoparticle Bloodstream Concentration For Cancer Therapies, Scarlett S. Bracey

Doctoral Dissertations

Currently, the most commonly used treatments for cancerous tumors (chemotherapy, radiation, etc.) have almost no method of monitoring the administration of the treatment for adverse effects in real time. Without any real time feedback or control, treatment becomes a "guess and check" method with no way of predicting the effects of the drugs based on the actual bioavailability to the patient's body. One particular drug may be effective for one patient, yet provide no benefit to another. Doctors and scientists do not routinely attempt to quantifiably explain this discrepancy. In this work, mathematical modeling and analysis techniques are joined together …

Halloysite Nanotube Composites For Sustained Release Of Antimocrobial Agents (Antiseptics And Antibiotics), Wenbo Wei

Doctoral Dissertations

Encapsulation of antimicrobial agents (simple antiseptics and more specific antibiotics) within micro-scale and nano-scale containers may provide prolonged and more evenly distributed drug release. One of such containers proposed at Louisiana Tech is natural halloysite clay nanotubes. Halloysite is an aluminosilicate tube with a length of approximately 1 µm, outer diameter of approximately 50 nm, and internal lumen of 15 nm. The chemical composition of halloysite is similar to more common clay–kaolinite, and it can be described as rolled sheets of kaolinite. Halloysite, loaded with drugs inside its lumen, has shown aqueous release of the loaded chemicals over 10-20 hours …

Discrete Geometric Based Stress Analysis Of The Lumbar Soft Tissues From In Vivo Kinematics, Joseph W. Mitchell

Doctoral Dissertations

Back pain in the region of the lumbar spine has become an increasingly significant problem among individuals in the United States and is a leading cause of disability and missed work days. At present, efforts focused on treating both the symptoms and causes of low back pain have proven to be difficult, and researchers and clinicians still do not fully understand the most effective means for treating the symptoms. Utilizing a biomechanics approach, it is assumed that lower back pain is, at least in part, associated with an increased localized stress.

Current models used to determine stresses are typically based …

Human Motion Analysis With Wearable Inertial Sensors, Xi Chen

Doctoral Dissertations

High-resolution, quantitative data obtained by a human motion capture system can be used to better understand the cause of many diseases for effective treatments. Talking about the daily care of the aging population, two issues are critical. One is to continuously track motions and position of aging people when they are at home, inside a building or in the unknown environment; the other is to monitor their health status in real time when they are in the free-living environment. Continuous monitoring of human movement in their natural living environment potentially provide more valuable feedback than these in laboratory settings. However, …

Green Manufacturing Of Nanoparticles For Biomedical Applications, Sijia Yi

Doctoral Dissertations

The vast majority of nanomaterials are chemically synthesized, a costly process, that is environmentally risky, and the produced nanoparticles are potentially toxic to patients. Nature-based nanomaterials, however, are proving to be much more biocompatible with lower environmental toxicity. Even though a variety of natural nanomaterials have been designed, fabrication technologies for the desired natural nanoparticles with reproducible quality, high productivity and low cost remain a challenge. My objective has been to establish strategies for the isolation, purification and characterization of nanoparticles using a production system based on green tea and fungus (Arthrobotrys oligospora) and also to develop new …

Development Of A Computational Methodology For Evaluating In Vivo Vertebral Mechanics In Subjects Having Various Conditions Of The Lumbar Spine, Christopher Brian Carr

Doctoral Dissertations

Treating and evaluating the causes of low back pain (LBP) is difficult and not fully understood. However, assessing the in vivo motions and loading characteristics in the lumbar spine may provide important data for progressing the diagnosis and treatment of pathologies linked with LBP.

This dissertation describes the development of a comprehensive approach for collecting both the kinematics and kinetics of the lumbar vertebrae under in vivo conditions. Forty-four subjects representing healthy, symptomatic, pathological, and surgically implanted (pre- and post-operative) conditions of the lumbar spine were evaluated using dynamic fluoroscopy and 3D-to-2D image registration to assess the motions of the …

An Investigation Of Markov Random Fields For Bayesian Reconstruction Of Single Photon Emission Computed Tomography, Lloyd Fredrick Arrowood

Doctoral Dissertations

This research investigates the use of Markov random fields for Bayesian reconstruction algorithms to be used with high-resolution and high-sensitivity SPECT systems for small animal imaging. It extends previous research on mechanical models for Bayesian image reconstruction by using a three-dimensional nonconforming finite element model and linear elasticity concepts to derive minimum potential energy functionals which regularize the reconstruction process. It combines dual collimator SPECT projection data by using high-resolution data to penalize lower-resolution data. It compares the new three-dimensional penalized reconstruction technique with existing penalized techniques through the use of modulation transfer and contrast discrimination functions.

Multiscale Modeling Of Toxoplasma Gondii, Adam Michael Sullivan

Doctoral Dissertations

Toxoplasma gondii is a potentially deadly parasite that uses a very unique way of manipulating the cell and immune systems. To investigate the mechanics of how the parasite spreads within hosts, several interwoven topics related to the study of within-host dynamics of Toxoplasma gondii are presented here. Understanding the complicated methods of how the parasite grows, dies, invades, replicates, and evades the host immune response is the critical aim of this independent research. Understanding the processes of acute and chronic infection are studied independently, followed by modeling the two processes in the same model. Finally, the dynamic models are simulated …

A Computational Model Of Nanoparticle Transport And Delivery In Tumor Tissue, Vishwa Priya Podduturi

Doctoral Dissertations

Determining the factors that influence the delivery of nanoparticles to tumors and understanding the relative importance of each of these factors is fundamental to optimize the drug delivery process. In this research, a model that combines random walk with the pressure driven flow of nanoparticles in a tumor vasculature is modeled. Nanoparticle movement in a cylindrical tube with dimensions similar to the tumor's blood capillary with a single pore is simulated. Nanoparticle velocities are calculated as a pressure driven flow over imposed to Brownian motion. During the study, the effect of red blood cells (RBC) is also studied by comparing …

Femtosecond Laser Patterned Templates And Imprinted Polymer Structures, Deepak Rajput

Doctoral Dissertations

Femtosecond laser machining is a direct-write lithography technique by which user-defined patterns are efficiently and rapidly generated at the surface or within the bulk of transparent materials. When femtosecond laser machining is performed with tightly focused amplified pulses in single-pulse mode, transparent substrates like fused silica can be surface patterned with high aspect ratio (>10:1) and deep (>10 μm) nanoholes. The main objective behind this dissertation is to develop single-pulse amplified femtosecond laser machining into a novel technique for the production of fused silica templates with user-defined patterns made of high aspect ratio nanoholes. The size of the …

Dynamic Mutual Capacitive Sensor For Human Interactions., Jonathan William Huber

Doctoral Dissertations

This dissertation introduces the novel concept of removing the ground conductive plate by utilizing body capacitance as the ground in the capacitive sensor, whereby circuit pressure sensing can occur with only one plate and one dielectric. Additionally, body capacitance sensing was limited to a binary touch-no-touch output, whereas the method presented here can sense various applied pressures. The resulting circuit acts as an antenna that receives local capacitance signals from a human interaction.

The advantage of this design is that it allows for both proximity sensing and pressure sensing (once the body part is touching the dielectric material). This setup …

Low Soluble Drug Encapsulation Based On Architecture Of Layer-By-Layer Assembly For Longer Circulation Time And Targeted Therapy, Pravin Pattekari

Doctoral Dissertations

A combined effect of sonication and layer-by-layer assembly (LbL) enhances the solubility of many poorly soluble inorganic and organic materials by forming stable particles with ca. 200 nm size and up to 90 wt% of loading. The entire method is reproducible, easy-to-handle, and flexible for varying surface properties according to the application of the materials. The method develops good colloidal stability of materials in buffers and maintains architecture for future improvement. A top-down approach, with a combined effect of sonication and LbL assembly, ruptures the material and allows adsorption of oppositely charged polyelectrolytes simultaneously. Thus, the approach is applicable for …

The Effect Of Network Transitions On Spontaneous Activity And Sycnhrony In Devloping Neural Networks, Jude P. J. Savarraj

Doctoral Dissertations

Connectivity patterns of developing neural circuits and the effects of its dynamics on network behavior, particularly the emergence of spontaneous activity and synchrony, are not clear. We attempt to quantify anatomical connectivity patterns of rat cortical cultures during different stages of development. By culturing the networks on dishes embedded with micro electrode arrays, we simultaneously record electrical activity from multiple regions of the developing network and monitor its electrical behavior, particularly its tendency to fire spontaneously and to synchronize under certain conditions. We investigate possible correlations between changes in the network connectivity patterns and spontaneous electrical activity and synchrony. Cocultures …

Intrinsic Mode Function Synchronization Measures For The Anticipation Of Seizures In Epilpsy, Daniel William Moller

Doctoral Dissertations

Epileptic seizures affect as many as 50 million people and often occur without warning or apparent provocation. We explore the applicability of noise-assisted Ensemble Empirical Mode Decomposition (EEMD) for patient-specific seizure anticipation synchronization measures as applied to the EEMD intrinsic mode function (IMF) output. Intracranial EEG data were obtained from pre-surgical monitoring at the Epilepsy Center of the University Hospital of Freiburg. Data from twenty patients were analyzed. For each recorded channel, non-overlapping time windows were submitted to the EEMD algorithm, producing twelve levels of IMFs. IMF synchronization measures (mean and maximum coherence, mean and maximum cross-correlation, correlation coefficient and …

Ultrasonication Assisted Layer-By-Layer Technology For The Preparation Of Multi-Functional Anticancer Drugs Paclitaxel And Lapatinib, Xingcai Zhang

Doctoral Dissertations

In this dissertation, ultrasonication assisted Layer-by-Layer (LbL) technology for the preparation of multifunctional poorly water-soluble anticancer drug nanoparticles, paclitaxel and lapatinib, has been developed. Many FDA approved drugs are very low soluble in water; therefore, it is very difficult to load and control their release and targeting efficiently, which greatly confines their application. The development of this method will pave the way for the development and application of those low soluble anticancer drugs.

In the first part of this dissertation, the first approach for powerful ultrasonication, the top-down approach (sonicating bulk drug crystals in polyelectrolyte solution), was successfully applied for …

New Microarray Image Segmentation Using Segmentation Based Contours Method, Yuan Cheng

Doctoral Dissertations

The goal of the research developed in this dissertation is to develop a more accurate segmentation method for Affymetrix microarray images. The Affymetrix microarray biotechnologies have become increasingly important in the biomedical research field. Affymetrix microarray images are widely used in disease diagnostics and disease control. They are capable of monitoring the expression levels of thousands of genes simultaneously. Hence, scientists can get a deep understanding on genomic regulation, interaction and expression by using such tools.

We also introduce a novel Affymetrix microarray image simulation model and how the Affymetrix microarray image is simulated by using this model. This simulation …

Engineering Microenvironments To Modulate Calcium Information Processing In Neuronal Cells, Kinsey Cotton Kelly

Doctoral Dissertations

Tissue engineered microenvironments were constructed to test the effects glial cells have on calcium information processing, and to mimic conditions in vivo for tumor invasion and residual cancer after resection of tumor. Submaximal, nM, glutamate (GLU) stimuli were applied to the engineered environments, and the resulting calcium dynamic behavior of neuronal cells was measured to help predict and interpret chaotic systems in the experimental realm. Calcium is a key signaling ion which signals through the N-methyl-D-aspartate (NMDA) glutamate receptor on the neuronal membrane. GLU binding to the NMDA receptor (NMDAR) causes a large and dynamic increase in neuronal intracellular calcium. …

Nonlinear Granger Causality And Its Application In Decoding Of Human Reaching Intentions, Mengting Liu

Doctoral Dissertations

Multi-electrode recording is a key technology that allows the brain mechanisms of decision making, cognition, and their breakdown in diseases to be studied from a network perspective. As the hypotheses concerning the role of neural interactions in cognitive paradigms become increasingly more elaborate, the ability to evaluate the direction of neural interactions in neural networks holds the key to distinguishing their functional significance.

Granger Causality (GC) is used to detect the directional influence of signals between multiple locations. To extract the nonlinear directional flow, GC was completed through a nonlinear predictive approach using radial basis functions (RBF). Furthermore, to obtain …

Microfluidic Devices Applied On Enriching Post –Translational Modified Proteins For Proteomics, Hui Xia

Doctoral Dissertations

In this work, microfluidic devices were developed for enriching post-translational modified proteins. Post-translational modifications (PTM) of proteins play essential roles in cellular physiology and disease. The identification of protein substrates and detection of modification site helps understand PTM-mediated regulation in essential biological pathways and functions in various diseases. However, PTM proteins are typically present only at trace levels, making them difficult to identify in mass spectrometry based proteomics. This work study is about the design, fabrication and testing of the microfluidic device for the enrichment of abundant amount of PTMs. Carbonylated protein is used as a representative PTM to illustrate …