Biomedical Engineering and Bioengineering Commons^™

Ablation Of Myocardial Tissue With Nanosecond Pulsed Electric Fields, Fei Xie, Frency Varghese, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Jonathan Philpott, Christian Zemlin

Bioelectrics Publications

Background

Ablation of cardiac tissue is an essential tool for the treatment of arrhythmias, particularly of atrial fibrillation, atrial flutter, and ventricular tachycardia. Current ablation technologies suffer from substantial recurrence rates, thermal side effects, and long procedure times. We demonstrate that ablation with nanosecond pulsed electric fields (nsPEFs) can potentially overcome these limitations.

Methods

We used optical mapping to monitor electrical activity in Langendorff-perfused New Zealand rabbit hearts (n = 12). We repeatedly inserted two shock electrodes, spaced 2–4 mm apart, into the ventricles (through the entire wall) and applied nanosecond pulsed electric fields (nsPEF) (5–20 kV/cm, 350 ns duration, …

Effects Of Nanosecond Pulse Electric Fields On Cellular Elasticity, Diganta Dutta, Anthony Asmar, Michael W. Stacey

Bioelectrics Publications

We investigated the effects of a single 60 nanosecond pulsed electric field (nsPEF) of low (15 kV/cm) and high (60 kV/cm) field strengths on cellular morphology and membrane elasticity in Jurkat cells using fluorescent microscopy and atomic force microscopy (AFM). We performed force displacement measurements on cells using AFM and calculated the Young's modulus for membrane elasticity. Differential effects were observed depending upon pulsing conditions. We found that a single nsPEF of low field strength did not induce any apparent cytoskeletal breakdown and had minor morphological changes. Interestingly, force measurements and calculation of Young's modulus showed a significant decrease in …

Possible Effects Of Nanosecond Pulsed Electric Fields On Proteins, Stephen J. Beebe

Bioelectrics Publications

No abstract provided.

Microbubble Generation By Piezotransducer For Biological Studies, W. Zhu, M. Alkhazal, M. Cho, S. Xiao

Bioelectrics Publications

Bubbles induced by blast waves or shocks are speculated to be the major cause of damages in biological cells in mild traumatic brain injuries. Microbubble collapse was found to induce noticeable cell detachment from the cell substrate, changes in focal adhesion and biomechanics. To better understand the bubble mechanism, we would like to construct a system, which allows us to clearly differentiate the impact of bubbles from that of shocks. Such a generator needs to be low profile in order to place under a microscope. A piezoelectric transducer system was designed to meet the need. The system uses either a …

Blast-Induced Mild Traumatic Brain Injury Through Ear Canal: A Finite Element Study, Praveen Akula, Yi Hua, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose The role of ear canal in transmitting blast waves to the brain is not clear. The goal of this work is to characterize the influence of ear canal on blast-induced mild traumatic brain injury through a computational approach.

Methods A three-dimensional human head model with single-side ear canal details was reconstructed from computed tomography images. The ear canal was positioned either facing the incident blast wave or facing away from the blast wave.

Results The blast wave-head interaction has demonstrated that the overpressure within the ear canal was substantially amplified when the ear directly faced the blast wave. When …

Iterative Ct Reconstruction From Few Projections For The Nondestructive Post Irradiation Examination Of Nuclear Fuel Assemblies, Muhammad Imran Khan Abir

Doctoral Dissertations

The core components (e.g. fuel assemblies, spacer grids, control rods) of the nuclear reactors encounter harsh environment due to high temperature, physical stress, and a tremendous level of radiation. The integrity of these elements is crucial for safe operation of the nuclear power plants. The Post Irradiation Examination (PIE) can reveal information about the integrity of the elements during normal operations and off‐normal events. Computed tomography (CT) is a tool for evaluating the structural integrity of elements non-destructively. CT requires many projections to be acquired from different view angles after which a mathematical algorithm is adopted for reconstruction. Obtaining many …

Measuring The Acute Physiological Effects Of Leptin In The Carotid Body, Richard Laurence Pye

Browse all Theses and Dissertations

Obesity is the healthcare crisis of our generation. Circulating levels of the adipokine leptin are proportional to adiposity and in addition to its role as a satiety factor leptin has been shown to have a host of pleiotropic effects. Among these effects is its role as a respiratory stimulant where it has been shown to have both whole body and central stimulatory effects on breathing. Porzionato et al. (2011) showed that leptin and leptin receptors are selectively expressed in the chemosensing type I cells of the carotid body. Carotid bodies are small chemosensitive organs that act as the primary peripheral …

The Guinea Pig Model For Organophosphate Toxicology And Therapeutic Development, Christopher Daniel Ruark

Browse all Theses and Dissertations

Organophosphates (OPs) are highly toxic insecticides and nerve agents that have been designed to inhibit the hydrolysis of acetylcholine by binding to the serine active site of acetylcholinesterase (AChE). They are one of the most common causes of human poisoning worldwide and are frequently intentionally used in suicides in agricultural areas. For this reason, there is a need for therapeutics to rescue those from intoxication. Obvious ethical concerns prevent humans from being subjected to OP exposure for therapeutic efficacy and safety testing. Therefore, animal surrogates for humans must be appropriately selected. A new paradigm, described herein, incorporating both in silico …

A Multi-Directional Treadmill Training Program For Improving Gait, Balance, And Mobility In Individuals With Parkinson’S Disease: A Case Series, Kimberly Smith, Kurt Jackson, Kimberly Edginton Bigelow, Lloyd L. Laubach

Mechanical and Aerospace Engineering Faculty Publications

Treadmill training is a commonly used intervention for improving gait in people with Parkinson’s disease (PD). However, little is known about how treadmill training may also influence balance and other aspects of mobility.

The purpose of this case series was to explore the feasibility and possible benefits of multi-directional treadmill training for individuals with PD. Four participants (62.3 ± 6.5 yrs, Hoehn & Yahr 2-4) performed 8 weeks of treadmill training 3 times per week. Weeks 1-4 included forward walking only, while weeks 5-8 included forward and multi-directional walking. Participants were tested every 4 weeks on 4 separate occasions. Outcome …

Novel Pulsatile Cardiac Assist Pump, Lakshmi Mohanadas

Wayne State University Theses

The project involve the research and development of a pulsatile, complex or continuous flow in biological and non-biological systems implantable heart assist pump. Specifically as a 20% cardiac assist for persons from congestive heart failure and other cardiac abnormalities. The pulsatile cardiac assist pump would provide upto 20% of the blood pumping process from the venous supply to the arterial supply. Current pumps are largely complete bypass pumps or large volume pumps that produce significant long term blood cell damage resulting in thrombosis. Most are not pulsatile which offers a significant physiological advantage. The pump under development is designed to …

Fabrication And Characterization Of A Robust, Field- Deployable, Optical Sensor Designed To Detect Particles In Oils., Navya Pandreka

Wayne State University Theses

Some types of bacteria and fungus can use iron or non-ferrous metals for their metabolic process. Sulfate-reducing bacteria can corrode pipes in the oil industry and high-end machinery. Both aerobic and anaerobic bacteria often degrade fuel quality and cause fuel system corrosion or alter the chemical properties of the fluid. This causes significant economic damage and safety concerns. Therefore, there is a need for a system to continuously monitor fuel or lubricant oil for the presence of bacteria and fungus.

The main goal of this project was to develop a sensor that can detect bacteria and other ferrous and non-ferrous …

Instrumentation And Development Of A Mass Spectrometry System For The Study Of Gas-Phase Biomolecular Ion Reactions, Ziqing Lin

Open Access Dissertations

Gas-phase reactions of biomolecular ions are highly relevant to the understanding of structures and functions of the biomolecules. Mass spectrometry is a powerful tool in investigating gas-phase ion chemistry. Various mass spectrometers have been developed to explore ion/molecule reactions, ion/ion reactions, ion/photon reactions, ion/radical reactions etc., both at atmospheric pressure and in vacuum. In-vacuum reactions have an advantage of involving pre-selecting the ions for the reactions using a mass analyzer. Over the decades, a variety of mass analyzers have been employed in the research of ion chemistry. Hybrid configurations, such as quadrupole ion trap with a time-of-flight and or a …

Quantitative Brain Electrical Activity In The Initial Screening Of Mild Traumatic Brain Injuries After Blast, Chengpeng Zhou

Wayne State University Theses

ABSTRACT

QUANTITATIVE BRAIN ELECTRICAL ACTIVITY IN THE INITIAL SCREENING OF MILD TRAUMATIC BRAIN INJURIES AFTER BLAST

by

CHENGPENG ZHOU

August 2015

Advisor: Dr. John Michael Cavanaugh, Dr. Chaoyang Chen

Major: Biomedical Engineering

Degree: Master of Science

Objective: Quantitative electroencephalography (QEEG) has been reported to be sensitive in the diagnosis and measurement of mild traumatic brain injury (mTBI) in civilian setting and thus may be a promising tool in individuals who have been exposed to blast forces. Using a swine model, this study investigated EEG changes early after blast exposure. The purpose was to determine if QEEG can detect brain activity …

Evaluation Of Mems Fabricated Fractal Based Free Standing Scaffolds For The Purposes Of Developing A Brain Bioreactor, Brandy Broadbent

Wayne State University Theses

The brain is the most complex organ in the body due to the multiple cell types,

billions of tightly packed synapses, extracellular matrix, and intricate topography. Microelectrical-mechanical

fabrication techniques exhibit promise in the field of neuronal

tissue engineering because the shape is highly controllable and a variety of materials can

be used in creation of bioreactors. This work evaluates the ability of a free standing TiO2

coated fractal scaffold to support healthy neuronal growth. Also evaluated is the

propensity for the neurons to take advantage of the 3D growing surface without the use of

complex extracellular matrix factors over the …

Creation Of A 3d Construct To Aid Cell Migration And Promote Cell Capture, Joseph Michael Sanders

Legacy Theses & Dissertations (2009 - 2024)

Most cancer-related deaths are attributed to metastasis. The tumor microenvironment is a complex environment which is not fully understood. The Nano Intravital Device (NANIVID) is a versatile, biocompatible device that allows for the manipulation of the tumor microenvironment in vitro and in vivo, providing a platform to study various aspects of tumor progression. The purpose of this study is to modify the NANIVID to resemble the tumor microenvironment in order to allow for a seamless transition from the in vivo environment into the engineered environment within the NANIVID. This engineered microenvironment will promote cell migration and cell capture. It has …

Brown Adipogenesis Of Mouse Embryonic Stem Cells In Alginate Microstrands, Andrea Mannarino Unser

Legacy Theses & Dissertations (2009 - 2024)

The ability of brown adipocytes (fat cells) to dissipate energy as heat shows great promise for the treatment of obesity and other metabolic disorders. Employing pluripotent stem cells, with an emphasis on directed differentiation, may overcome many issues currently associated with primary fat cell cultures. However, brown adipocytes are difficult to transplant in vivo due to the instability of fat, in terms of necrosis and neovascularization, once injected. Thus, 3D cell culture systems that have the potential to mimic adipogenic microenvironments are needed, not only to advance brown fat implantation, but also to better understand the role of brown adipocytes …

Comparison Of Glucose, Fructose And Sucrose Amperometric And Thermal Sensors For Detection Of Carbohydrates In Living Plant Tissue, Scott Mcadoo

Legacy Theses & Dissertations (2009 - 2024)

Ecologists currently cannot test concentrations of carbohydrates in sap in vivo. Testing carbohydrates with current technology would require destructive tissue sampling. The tissue sampling involves large amounts of time and money to collect and test. Aphids are an insect that can bypass a tree’s passive immune system and feed off a phloem region for weeks. A series of enzymatic biosensors could be used to detect the concentration changes of specific carbohydrates. A calcium chelant can be added to defeat a tree’s immune system like an aphid. The detection of three carbohydrates, fructose, glucose and sucrose are involved in this study. …

3d-Bioengineering Of The Conventional Outflow Tract For High Throughput Drug Or Gene Transfer Screening For Glaucoma Treatment, Cula Nolise Dautriche

Legacy Theses & Dissertations (2009 - 2024)

Among ocular pathologies, glaucoma remains the second leading cause of blindness. The molecular mechanisms that lead to glaucoma have been attributed to damage of the conventional outflow tract. Conventional outflow tissues, a composite of the trabecular meshwork and the Schlemm's canal, regulate and maintain homeostatic responses of aqueous humor outflow. In glaucoma, drainage of aqueous humor into the Schlemm's canal is hindered, leading to an increase in intraocular pressure (IOP). That increase in IOP is directly correlated with retinal ganglion cell death, eliminating the relay of visual information to the thalamus and visual cortex, leading to blindness. Although disturbance in …

Bioengineering In Vitro Human Trabecular Meshwork Models For Glaucoma Therapeutic Screening, Karen Yud Torrejon

Legacy Theses & Dissertations (2009 - 2024)

Glaucoma refers to a group of slowly progressing eye disorders that lead to damage to the optic nerve, resulting in irreversible vision loss. Recent statistics by the World Health Organization places glaucoma as a leading cause of blindness worldwide, affecting nearly 80 million people. Lowering intraocular pressure (IOP) is currently the only effective target for therapeutic intervention in glaucoma. IOP is mostly controlled by the outflow of the aqueous humor (AH) through the trabecular meshwork (TM). The TM and adjacent endothelium of Schlemm’s canal, known as the conventional outflow-tract, control AH outflow and thus determine IOP.

Design And Development Of A Ventilation Chamber For Testing Efficacy Of Tracheal Stents, Caroline N. Horton

Theses and Dissertations

Tracheobronchial malacia results in a weakening of the tracheal walls, leading to increased difficulty breathing. Stents are used to reopen the lumen of the trachea, however, current models are not personalized to each patient, leading to migration, inflammation, and breakage of the stents. In order to successfully test novel stent designs, a ventilation chamber is needed to recreate the breathing conditions of the body.

The following describes the iterative development of a ventilation chamber, which allows inflation and deflation of lungs via negative pressure ventilation, as representative of an actual body undergoing respiration. Previous work shows that lungs are not …