Biomedical Engineering and Bioengineering Commons^™

A Backing Device Based On An Embedded Stiffener And Retractable Insertion Tool For Thin-Film Cochlear Arrays, Radheshyam Tewari

Dissertations, Master's Theses and Master's Reports - Open

Intracochlear trauma from surgical insertion of bulky electrode arrays and inadequate pitch perception are areas of concern with current hand-assembled commercial cochlear implants. Parylene thin-film arrays with higher electrode densities and lower profiles are a potential solution, but lack rigidity and hence depend on manually fabricated permanently attached polyethylene terephthalate (PET) tubing based bulky backing devices. As a solution, we investigated a new backing device with two sub-systems. The first sub-system is a thin poly(lactic acid) (PLA) stiffener that will be embedded in the parylene array. The second sub-system is an attaching and detaching mechanism, utilizing a poly(N-vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PDLLA) copolymer-based …

Design And Application Of Wireless Passive Magnetoelastic Resonance And Magnetoharmonic Force Sensors, Brandon D. Pereles

Dissertations, Master's Theses and Master's Reports - Open

The objective of the work described in this dissertation is the development of new wireless passive force monitoring platforms for applications in the medical field, specifically monitoring lower limb prosthetics. The developed sensors consist of stress sensitive, magnetically soft amorphous metallic glass materials. The first technology is based on magnetoelastic resonance. Specifically, when exposed to an AC excitation field along with a constant DC bias field, the magnetoelastic material mechanically vibrates, and may reaches resonance if the field frequency matches the mechanical resonant frequency of the material. The presented work illustrates that an applied loading pins portions of the strip, …

Fabrication Of Drug Eluting Ti Implants For Dental/Orthopedic Applications, Azhang Hamlekhan

Dissertations, Master's Theses and Master's Reports - Open

Titanium and its alloys are typically used for fabrication of dental and orthopedic implants as they possess various desirable properties including biocompatibility and corrosion resistance. In spite of such benefits, titanium implants show lack of osseointegration after surgery in minor cases. The objective of this research has been to modify the surface of titanium alloy for medical applications through increasing surface hydrophilicity and drug loading. Primarily, anodization method is employed for fabrication of nanotubes on titanium surface to act as anchoring cite for cells.

Considering the key role of surface hydrophilicity on cellular attachment to the surface and subsequent biological …

Apelin Regulation Of K-Cl Cotransport In Vascular Smooth Muscle Cells., Neelima Sharma

Browse all Theses and Dissertations

Atherosclerosis and high circulating levels of oxidized low density lipoproteins (oxLDL) are considered among the most important risk factors for the occurrence and development of cardiovascular disease (CVD). During the atherosclerotic lesion repair, phenotypic transition of vascular smooth muscle cells (VSMCs) from contractile to synthetic states plays a central role. In this process, enhanced proliferation/migration of VSMCs, from the tunica media to the intima, is required to sustain blood vessel endothelium integrity, and for inducing vessel wall remodeling in response to injury. At the molecular level, the activity of electroneutral potassium-chloride cotransporters or KCCs, is necessary to: a) allow changes …

A Compact Theory Of Magnetic Nerve Stimulation: Predicting How To Aim, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: A compact theory that predicts quantitatively when and where magnetic neurostimulation will occur is needed as a guide to therapy, ideally providing a single equation that defines the target volume of tissue excited by single or dual coils. Methods: A first-principles analysis of magnetic stimulation incorporating a simplified description of electromagnetic fields and a simplified cable theory of the axon yields a mathematical synthesis predicting how to aim. Results: Nerve stimulation produced by a single circular coil having one or more closely packed turns occurs in donut shaped volume of tissue beneath the coil. Axons spanning several millimeters are …

Noninvasive Measurement Of Cardiac Stroke Volume Using Pulse Wave Velocity And Aortic Dimensions: A Simulation Study, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: Concerns about the cost-effectiveness of invasive hemodynamic monitoring in critically ill patients using pulmonary artery catheters motivate a renewed search for effective noninvasive methods to measure stroke volume. This paper explores a new approach based on noninvasively measured pulse wave velocity, pulse contour, and ultrasonically determined aortic cross sectional area. Methods: The Bramwell-Hill equation relating pulse wave velocity to aortic compliance is applied. At the time point on the noninvasively measured pulse contour, denoted th, when pulse amplitude has fallen midway between systolic and diastolic values, the portion of stroke volume remaining in the aorta, and in turn the …

Choosing Inclusion Criteria That Minimize The Time And Cost Of Clinical Trials, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

AIM: To present statistical tools to model and optimize the cost of a randomized clinical trial as a function of the stringency of patient inclusion criteria. METHODS: We consider a two treatment, dichotomous outcome trial that includes a proportion of patients who are strong responders to the tested intervention. Patients are screened for inclusion using an arbitrary number of test results that are combined into an aggregate suitability score. The screening score is regarded as a diagnostic test for the responsive phenotype, having a specific cutoff value for inclusion and a particular sensitivity and specificity. The cutoff is a measure …

The Application Of Graphene Films In Biosensing And Electrowetting, Xuebin Tan

Wayne State University Dissertations

In recent years, graphene has been found to possess extraordinary electronic, optical, mechanical and electrochemical properties. Graphene is optically transparent and mechanically flexible, and has high electron mobility and conductivity. In this thesis, we propose to investigate graphene's properties in the detection of biomolecules as well as the manipulation of biological samples. Graphene without defects has high charge carrier mobility and surface areas, which is ideal for biosensors. However, literature shows a lot of variations in the measurements using graphene biosensors. In addition, the surface functionalization of graphene in order to enhance the specificity has not been fully investigated yet. …

High-Performance Accelerometer Based On Asymmetric Gapped Cantilevers For Physiological Acoustic Sensing, Yating Hu

Wayne State University Dissertations

Continuous or mobile monitoring of physiological sounds is expected to play important role in the emerging mobile healthcare field. Because of the miniature size, low cost, and easy installation, accelerometer is an excellent choice for continuous physiological acoustic signal monitoring. However, in order to capture the detailed information in the physiological signals for clinical diagnostic purpose, there are more demanding requirements on the sensitivity/noise performance of accelerometers. In this thesis, a unique piezoelectric accelerometer based on the asymmetric gapped cantilever which exhibits significantly improved sensitivity is extensively studied. A meso-scale prototype is developed for capturing the high quality cardio and …

Degradable Borate Glass Polyalkenoate Cements, L. Shen, A. Coughlan, Mark R. Towler, M. Hall

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag₂O-Na₂O-CaO-SrO-ZnO- TiO₂-B₂O₃ were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO₂ (7.5 mol %) …

Tissue Engineering Scaffold Fabrication And Processing Techniques To Improve Cellular Infiltration, Casey Grey

Theses and Dissertations

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold …

Evaluation Of Functional Near Infrared Spectroscopy (Fnirs) For Assessment Of The Visual And Motor Cortices In Adults, Brenna Giacherio

Browse all Theses and Dissertations

Introduction: Functional near-infrared spectroscopy (fNIRS) is a relatively young technique in the field of medical imaging. As such, it has yet to be widely implemented for clinical use, despite its promising advantages. However, unlike fMRI-its much bulkier and costly counterpart-fNIRS has yet to be proven as a standalone imaging tool within a clinical setting, particularly that of ophthalmology or physical therapy.

Methods: Ten healthy young adults (23.8 ± 4.8 years) participated in the study. Activation of the visual cortex was achieved utilizing various reversing checkerboard stimuli across three data collection sessions for each participant. Further, activation of the motor cortex …

Rab3a As A Modulator Of Homeostatic Synaptic Plasticity, Andrew G. Koesters

Browse all Theses and Dissertations

The nervous system is faced with perturbations in activity levels throughout development and in disease or injury states. Neurons need to adapt to these changes in activity, but also need to maintain circuit firing within a normal range to stabilize the network from becoming too excited or too depressed. Homeostatic synaptic plasticity, the compensatory increase or decrease in synaptic strength as a result of excessive circuit inhibition or excitation, is a mechanism that the nervous system utilizes to keep network activity at normal levels. Despite intense effort, little is known about the mechanisms underlying homeostatic synaptic plasticity. Numerous studies have …

Segmentation And Analysis Of Mris Of Infants With Dysphagia, Irfaan A. Dar

Browse all Theses and Dissertations

Neonates are at a rapid stage of development from birth throughout childhood. Impairments to certain cortical areas can result in long lasting neuro-cognitive dysfunctions. Disorders to the swallowing neural pathways can have detrimental effects throughout life course since methods to provide nutrition can be comprised. Dysphagia, or the inability to swallow, can be caused by a multitude of reasons, chiefly neurological, but the underlying disruptions to the neural pathways are not defined. In this study we investigated the growth of multiple cortical areas involved in the swallowing pathway and categorized feeding outcomes with neural growth. Results showed that infants that …

Finite Element Simulation Of Skull Fracture Evoked By Fall Injuries, Anthony Vicini

Browse all Theses and Dissertations

This study presents novel predictive equations for von Mises stresses and deflection of bones in the frontal and lateral regions of the skull. The equations were developed based on results of a finite element model developed here. The model was validated for frontal and lateral loading conditions with input values mimetic to fall scenarios. Using neural network processing of the information derived from the model achieved R2 values of 0.9990 for both the stress and deflection. Based on the outcome of the fall victims, a threshold von Mises stress of 40.9 to 46.6 MPa was found to indicate skull fracture …

The Role Of Subunit Iii In The Functional And Structural Regulation Of Cytochrome C Oxidase In Rhodobacter Spheroids, Khadijeh Salim Alnajjar

Browse all Theses and Dissertations

Cytochrome c oxidase (COX) catalyzes the oxidation of ferrocytochrome c and the reduction of oxygen to water while concomitantly translocating protons across the inner mitochondrial membrane. The catalytic core of COX consists of three subunits that are conserved from the bacterial to the mitochondrial forms of the enzyme. Subunits I and II (SUI and SUII) contain the metal centers where electrons are transferred and oxygen binds for reduction. Subunit III (SUIII) does not contain any metals and has an unknown function. It contains three conserved histidine residues (3, 7 and 10) that are surface exposed and are in close proximity …

A Method For Non-Invasive, Automated Behavior Classification In Mice, Using Piezoelectric Pressure Sensors, Steven R. Gooch

Theses and Dissertations--Electrical and Computer Engineering

While all mammals sleep, the functions and implications of sleep are not well understood, and are a strong area of investigation in the research community. Mice are utilized in many sleep studies, with electroencephalography (EEG) signals widely used for data acquisition and analysis. However, since EEG electrodes must be surgically implanted in the mice, the method is high cost and time intensive. This work presents an extension of a previously researched high throughput, low cost, non-invasive method for mouse behavior detection and classification. A novel hierarchical classifier is presented that classifies behavior states including NREM and REM sleep, as well …

Peroxisome Proliferator-Activated Receptor Alpha: Insight Into The Structure, Function And Energy Homeostasis, Dhawal P. Oswal

Browse all Theses and Dissertations

Peroxisome proliferator-activated receptor alpha (PPAR alpha) belongs to the family of ligand-activated nuclear transcription factors and serves as a lipid sensor to regulate nutrient metabolism and energy homeostasis. The transcriptional activity of PPAR alpha is thought to be regulated by the binding of exogenous ligands (example, fenofibrate, TriCor), as well as endogenous ligands including fatty acids and their derivatives. Although long-chain fatty acids (LCFA) and their thioesters (long-chain fatty acyl-CoA; LCFA-CoA) have been shown to activate PPAR alpha of several species, the true identity of high-affinity endogenous ligands for human PPAR alpha (hPPAR alpha) has been more elusive. This two …

The Pseudomonas Syringae Type Iii Effector Hopd1 Suppresses Effector-Triggered Immunity, Localizes To The Endoplasmic Reticulum, And Targets The Arabidopsis Transcription Factor Ntl9, Anna Block, Tania Y. Toruno, Christian G. Elowsky, Chi Zhang, Jens Steinbrenner, Jim Beynon, James R. Alfano

Nebraska Center for Biotechnology: Faculty and Staff Publications

Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and …

Android-Based Smartphone Application Simulation And Systematic Design To Reduce Medication Administration Error In Prehospital Emergency Care., Natalie Vazquez

Theses and Dissertations

Since 1999 when the report To Err is Human: Building a Safer Health System was released, medical errors have come into focus (Kohn, 2000). In an effort to reduce medication administration errors in prehospital emergency care, an android-based smartphone application simulation was created. The app has components including QR barcode scanning, text to speech for medication cross-checking, weight-based medication dose calculations, and time stamped medication data wirelessly transferring to a database in real-time. Color standard identification was implemented, aiding to a designed systematic process for patient treatment to reduce medication errors. Direct observation was performed of emergency patient calls with …