Biomedical Engineering and Bioengineering Commons^™

Composition-Structure-Property Relationships For Experimental Composite Nerve Guidance Conduits, Xiaofang Zhang

Theses

Many Nerve Guidance Conduits (NGCs) have been approved by the Food and Drug Administration (FDA) as an alternative to nerve autografting for guiding peripheral nerve regeneration. However these materials offer little therapeutic potential for favourable axon growth environment, and difficulty in balancing the mechanical properties and the degradation rate of the implanted material is also a contemporary challenge. This project involved the design of experimental composite NGCs comprising glass particles and Pluronic FI27 in the copolymer (poly(lactic-co-glycolic acid)) and examined the composition-structure-property relationships for such materials. Three glasses (0.5Si-(x) Na-0.2Ca-0.13Zn-(0.17-x) Ce) (0.0.04 > x > 0.14) were produced. Glasses were characterised using …

The Bioactivity And Ion Release Of Titanium-Containing Glass Polyalkenoate Cements For Medical Applications, A. W. Wren, N. M. Cummins, F. R. Laffir, S. P. Hudson, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ion release profiles and bioactivity of a series of Ti containing glass polyalkenoate cements. Characterization revealed each material to be amorphous with a T_g in the region of 650-660°C. The network connectivity decreased (1.83-1.35) with the addition of TiO₂ which was also evident with analysis by X-ray photoelectron spectroscopy. Ion release from cements were determined using atomic absorption spectroscopy for zinc (Zn^₂₊), calcium (Ca^₂₊), strontium (Sr^₂₊), Silica (Si^₄₊) and titanium (Ti4+). Ions such as Zn^₂₊ (0.1-2.0 mg/l), Ca²⁺ (2.0-8.3 mg/l,) Sr²⁺ (0.1-3.9 mg/l), and S^{i4+ …}

Nanosecond Pulse Electrical Fields Used In Conjunction With Multi-Wall Carbon Nanotubes As A Potential Tumor Treatment, Michael W. Stacey, Christopher Osgood, Bhargava Subhash Kalluri, Wei Cao, Hani Elsayed-Ali, Tarek Abdel-Fattah

Bioelectrics Publications

The objectives of this communication were to fabricate pure samples of multi-walled carbon nanotubes (MWCNTs) and to determine their toxicity in tumor cell lines. MWCNTs were dispersed in a concentration of the surfactant T80 that was minimally toxic. Cell-type variation in toxicity to MWCNTs was observed but was not significantly different to unexposed controls. Additionally, we investigated the increased cell killing of the pancreatic cancer cell line PANC1 when exposed to ultrashort (nanosecond) pulsed electrical fields (nsPEF) in the presence of MWCNTs as a potential form of cancer therapy. We hypothesized that the unique electronic properties of MWCNTs disrupt cell …

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 …

Electro-Gene Transfer To Skin Using A Noninvasive Multielectrode Array, Siqi Guo, Amy Donate, Gaurav Basu, Cathryn Lundberg, Loree Heller, Richard Heller

Bioelectrics Publications

Because of its large surface area and easy access for both delivery and monitoring, the skin is an attractive target for gene therapy for cutaneous diseases, vaccinations and several metabolic disorders. The critical factors for DNA delivery to the skin by electroporation (EP) are effective expression levels and minimal or no tissue damage. Here, we evaluated the non-invasive multielectrode array (MEA) for gene electrotransfer. For these studies we utilized a guinea pig model, which has been shown to have a similar thickness and structure to human skin. Our results demonstrate significantly increased gene expression 2 to 3 logs above injection …

A Database For Estimating Scanner-Specific Ct Dose, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: To develop a database for estimating scanner-specific organ dose in a voxelized patient model for any spectral shape and angular tube current modulation setting. The database enables the estimation of organ dose for both existing and novel acquisition techniques without requiring Monte Carlo simulations.

Methods: The transport of monoenergetic photons through three phantoms was simulated with the PENELOPE Monte Carlo radiation transport routines at 5 – 150 keV in 1 keV increments at 1000 projections in 0.36 degree increments. The source-to-detector distance for each simulation was 100 cm, with a source-to-isocenter distance of 50 cm. The lateral and axial …

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]. …

On Improving Electrooculogram-Based Computer Mouse Systems: The Accelerometer Trigger, Johnalan Keegan, Edward Burke, James Condron, Eugene Coyle

Conference Papers

Eye tracking is a well-established method of computer control for profoundly paralysed people (Anson et al., 2002). Cameras are commonly used to track eye movements (Morimoto et al., 2005) but one alternative is the bioelectrical signal known as the electrooculogram (EOG). There are some EOG mouse control systems that facilitate the use of GUI applications, but certain actions, which are straightforward using a conventional mouse, remain impossible. Unless the eyes are tracking a target, they move in saccades (jumps), making it impossible to voluntarily trace out smooth trajectories with one's gaze, as would be required to draw a smooth curve. …

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 …

Evaluation Of A Stream‐Aquifer Analysis Test For Deriving Reach‐Scale Streambed Conductance, Garey A. Fox, Derek M. Heeren, Michael A. Kizer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Extracting groundwater from pumping wells located adjacent to streams can reduce streamflow, a result that is known as alluvial well depletion. Numerous analytical solutions have been developed for alluvial well depletion that vary in their mathematical complexity. Predicted drawdown by the analytical solutions can be matched to observed drawdown from a stream–aquifer analysis (SAA) test (i.e., a pumping test adjacent to a stream) to simultaneously estimate aquifer and streambed hydrologic parameters. However, only a few SAA tests have been documented in the literature and compared to field–measured streambed parameters. Therefore, the objective of this research was to perform an SAA …

Correlation Between Alternans Of Early And Late Phases Of Ventricular Action Potential, Sonam Chourasia

Theses and Dissertations--Biomedical Engineering

Several studies suggest that action potential duration (APD) alternans play an important role in initiation of arrhythmias, while less is known about the alternans of early phases of action potential (AP) and phase relation between the two. Transmembrane potentials recorded from swine and canine ventricles were analyzed to determine the correlation and phase relation between alternans of early and late phases of an AP. In both species, for activation intervals ≤ 400 ms, action potential amplitude (APA) alternans occurred≥ 50% of times when APD alternans occurred and vice versa, both were mostly in phase. Also, alternans of APA and APD …

Creep Behaviour Of Hand Laminated Glass Reinforced Polymer Composites., Brian Quinn

Theses

The creep behaviour of hand laminated, glass fiber reinforced polyester composites were studied at coupon level, due to the use of similar materials in long term load bearing civil and structural engineering applications. Creep predictions were made by fitting the parameters of several viscoelastic models to experimental creep data as well as two accelerated test methods, time temperature superposition (TTS) and frequency time transformations (FTT). TTS experiments were carried out in a dynamic mechanical analyzer (DMA) in three point bending mode for three types of material systems. Creep compliance master curves representing the linear viscoelastic creep response at reference temperatures …

Engineered Basal Lamina Equivalent - Fabrication And Biomedical Applications, Deepika Tamuly

Bioengineering Theses - Archive

A novel technique based on the principle of solvent casting is developed to create uniform, ultrathin and stackable films of Collagen I/IV and ECMgel for use as Engineered Basal Lamina Equivalent. The mixture of these two proteins provides key molecular elements (laminin, collagen type IV, entactin and perlecan) in a basal lamina with strong mechanical properties (collagen type I). Rat tail derived collagen solution is mixed with ECMgel, and the solution is cast onto PDMS molds and air dried in a custom built air tunnel. The dried membranes are briefly UV cross-linked, peeled off from the PDMS mold to be …

Implementation Of A Pain Generator Controlled By Pressure And Feasability In Its Applications For Functional Near-Infrared Spectroscopy, Pamela Agwa Tebebi

Bioengineering Theses - Archive

Pain is a sensory and emotional experience as a result of possible or definite tissue damage. The level of pain is subjective to the individual's consciousness of sensory stimuli. Pain stimuli can be noxious (i.e., potentially damaging) or innocuous (i.e., normally not painful). Therefore, pain perception can be based on the degree of the stimuli. Studies have been done using brain imaging modalities to assess pain. Functional Near-infrared spectroscopy (fNIRS) is a noninvasive imaging tool and has been used to study the hemodynamic variations in the brain induced by a variety of activations. This research was a feasibility study to …

Investigation Of Brain Activity In Prefrontal Cortex Under Noxious Pain Stimuli And During Psychological Test Using Functional Near Infrared Spectroscopy, Sabin Khadka

Bioengineering Theses - Archive

Functional Near Infrared Spectroscopy (fNIRS) is a non-invasive functional neuroimaging technique, which measures changes in oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) concentrations based on the principle of near infrared spectroscopy. For my thesis, I have utilized fNIRS in the prefrontal regions to study cognitive functions under noxious pain and during a psychological test. The fNIRS signals were acquired from the prefrontal cortex (PFC) in order to investigate the hemodynamic response under noxious pain stimuli. The measurement consisted of two different visits separated by seven to ten days with two different levels of pain intensity. From the observations, PFC shows significant deactivation …