Biomedical Engineering and Bioengineering Commons^™

Finite Element Modeling Of Temperature Elevation Due To Nir Exposure In Neural Tissue, Atabek Can Yucel

Theses

Near infrared (NIR) lasers have been used in various types of medical applications. Heating is one of the most important concerns in the neural tissue when illuminated with NIR light. Rodent models are frequently used to study laser-tissue interactions. As a part of ongoing research project in the neural interface laboratory, direct measurements of temperature in the rat brain cortex as a response to a pulsed sequence of NIR laser beam are available. In this thesis, finite element modeling approach is used to model and simulate the temperature elevation in neural tissue under the effect of NIR laser pulsing. Steady …

Effect Of Scan Time On Resting State Parameters, Dhruti Patel

Theses

In the past decade the interest in studying the spontaneous low-frequency fluctuations (LFF) in a resting-state brain has steadily grown. By measuring LFF (< 0.08 Hz) in blood-oxygen-level-dependent (BOLD) signals, resting-state functional magnetic resonance imaging (rs-fMRI) has proven to be a powerful tool in exploring brain network connectivity and functionality. Rs-fMRI data can be used to organize the brain into resting state networks (RSNs). In this thesis, rs-fMRI data are used to determine the minimum data acquisition time necessary to detect local intrinsic brain activity as a function of both the amplitude of low frequency fluctuations (ALFF) and the fractional amplitude of low frequency fluctuations (fALFF) in BOLD signals in healthy subjects. The data are obtained from 22 healthy subjects to use as a baseline for future rs-fMRI analysis. Voxel-wise analysis is performed on the whole brain, gray matter volume, and two previously established RSNs: the default mode network (DMN) and the visual system network, for all the subjects in this study.

Pearson’s correlation coefficients (r-values) are calculated from each subject. The entire time series for one subject is divided into 31 subsections and the r-values are calculated between each consecutive subsection in a subject. In total, there are 30 r- values. To better understand what the results mean across subjects and within subjects Fisher transformations are applied to the 30 calculated r-values for each subject to get a normal z-distribution. The mean across 22 subjects’ z-values is …

Nir Light Transmission Through Skin And Muscle, Deniz Ozgulbas

Theses

Light has been used extensively in the medical field for both therapeutic and diagnostic applications. Tissue optical window or therapeutic window defines the range of wavelengths where the light has the maximum transmittance through tissue. In this range, absorption and scattering effects are relatively lower when compared to the visible or middle infrared wavelengths. Knowledge of the transmittance through tissue can help determine the effective light intensities in medical applications.

The objective of this thesis is to determine the NIR light transmission through different thicknesses of animal tissue and its spatial spread due to the scattering effect. Primarily pork skin …

Admittance Control Of The Intelligent Assist Robot Manipulator For People With Duchenne Muscular Dystrophy, Madeline Corrigan

Theses

Duchenne muscular dystrophy (DMD), a neuromuscular disease with a prevalence of 1 in 3500 male births, results in characteristic muscle weakness which is progressive with age and leads to loss of independence. And, in this population, maintaining optimal quality of life depends on the preservation of self-sufficiency. Despite the loss of function, non-ambulant people with DMD retain some muscle strength, just not sufficient strength to overcome the force of gravity. There are a number of upper-limb passive and active orthotic devices that attempt to augment the loss of upper limb function in people with DMD by taking advantage of this …

Brain Computer Interface Based Neurorehabilitation Technique Using A Commercially Available Eeg Headset, Abhineet Mishra

Theses

Neurorehabilitation has recently been augmented with the use of virtual reality and rehabilitation robotics. In many systems, some known volitional control must exist in order to synchronize the user intended movement with the therapeutic virtual or robotic movement. Brain Computer Interface (BCI) aims to open up a new rehabilitation option for clinical population having no residual movement due to disease or injury to the central or peripheral nervous system. Brain activity contains a wide variety of electrical signals which can be acquired using many invasive and non-invasive acquisition techniques and holds the potential to be used as an input to …

Fabrication And Evaluation Of A Collagen-Based Fiber-Gel Three-Dimensional Construct For Peripheral Nerve Repair, Mevan Lakmal Siriwardane

Dissertations

Nerve regeneration following a peripheral nerve injury often relies on growth cone- mediated guidance and the presence of Schwann cells to support the regenerating axons and remyelinate portions of denervated nerve pathways. The emphasis of this work is to develop a synthetic nervous tissue construct that contains similar basal lamina or extracellular matrix to peripheral nerve in order to achieve a level of effectiveness in nerve repair and future peripheral nerve regeneration applications. To this end, three- dimensional nervous tissue constructs consisting of type I collagen are fabricated into a composite biomaterial scaffold to promote contact-guided growth of neuronal and …

Quantification Of Neural Substrates Of Vergence System Via Fmri, Yelda Alkan

Dissertations

Vergence eye movement is one of the oculomotor systems which allow depth perception via disconjugate movement of the eyes. Neuroimaging methods such as functional magnetic resonance imaging (fMRI) measure neural activity changes activity in the brain while subjects perform experimental tasks. A rich body of primate investigations on vergence is already established in the neurophysiology literature; on the other hand, there are a limited number of fMRI studies on neural mechanisms behind the vergence system.

The results demonstrated that vergence system shares neural sources and also shows differentiation within the boundaries of frontal eye fields (FEF) and midbrain of the …

Quantification Of Human Motion On Roller Coaster Rides, Chirag Burman

Theses

Case reports have been published of people experiencing symptoms of traumatic brain injury (TBI) and/or ailments of the vascular tissue around the head. These reports pointed towards G-forces, a scalar measure without a specified direction, which represent the measure of the acceleration of an object divided by acceleration caused by gravity (9.81 m/s²), as a cause of said injuries. Research has been conducted on quantifying the G-forces experienced while on roller coasters, as well as the change in heart rate. However these studies have not been able to show a link between roller-coasters and symptoms.

This thesis aims …

Fuzzy Logic For Task Space Telemanipulation Of A Five Fingered Robotic Hand, Raaghavann Srinivasan

Theses

This work presents a fuzzy logic based HandyMan (Hand gesture commands for grasping and manipulation) system to recognize the operator's hand gestures during task space telemanipulation. A combination of joint positions may be shared between at least two manipulation gestures. To avoid misinterpretation of gestures by the gesture recognition system, six new manipulation gestures were introduced. The gestures are produced by the user wearing a CyberGlove™.

This system replaces the previous HandyMan gesture recognition method. The output of the fuzzy system drives the state machines to implement the gestures with the robot hand.

The experimental results show that the proposed …

Diffuse Axonal Injury Effect On Myelinating Cells And Axons, Jennifer Alison Zalk

Theses

There is no supporting evidence whether myelin degeneration in diffuse axonal injury (DAI) of the white matter is due to death of myelinating oligodendrocytes or secondary axotomy. Cortical neurons are not able to remain healthy in culture to have their axons myelinated. Dorsal root ganglion (DRG) neurons have been shown to be myelinated by cortical oligodendrocytes in culture. An in vitro stretch injury model was used to analyze the DRG axon pathology during and after injury. DRG myelinating Schwann cells are analyzed to demonstrate what is expected from injury to oligodendrocytes. DRG axons demonstrated a high tolerance to stretch …