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Statistical Medial Model Dor Cardiac Segmentation And Morphometry, Hui Sun 2010 University of Pennsylvania

Statistical Medial Model Dor Cardiac Segmentation And Morphometry, Hui Sun

Publicly Accessible Penn Dissertations

In biomedical image analysis, shape information can be utilized for many purposes. For example, irregular shape features can help identify diseases; shape features can help match different instances of anatomical structures for statistical comparison; and prior knowledge of the mean and possible variation of an anatomical structure's shape can help segment a new example of this structure in noisy, low-contrast images. A good shape representation helps to improve the performance of the above techniques. The overall goal of the proposed research is to develop and evaluate methods for representing shapes of anatomical structures. The medial model is a shape ...


Evaluating The Use Of Engineered Nervous Tissue Constructs In The Repair Of Peripheral Nerve Lesions And Amputations, Niranjan Kameswaran 2010 University of Pennsylvania

Evaluating The Use Of Engineered Nervous Tissue Constructs In The Repair Of Peripheral Nerve Lesions And Amputations, Niranjan Kameswaran

Publicly Accessible Penn Dissertations

Severe trauma to the limbs can often result in the lesioning, or even amputation, of the underlying peripheral nerves. In these cases, endogenous neural repair mechanisms are compromised and a path to the end target may be lost, resulting in the need for surgical intervention. Current repair strategies are incapable of maintaining this regenerative pathway, or providing a bridge to a surrogate end target, often resulting in incomplete repair.

This thesis describes the development and evaluation of a novel method of addressing peripheral nerve lesions and amputations that utilizes living tissue-engineered neural grafts. These grafts are created by the controlled ...


Regulation Of Angiogenesis By Adhesive And Mechanical Cues From The Extracellular Matrix, Colette Shen 2010 University of Pennsylvania

Regulation Of Angiogenesis By Adhesive And Mechanical Cues From The Extracellular Matrix, Colette Shen

Publicly Accessible Penn Dissertations

Angiogenesis, the sprouting of new capillaries from existing blood vessels, is essential for the survival of tissues and normally occurs during development and wound healing. Successful vascularization of engineered tissues is currently a major challenge, as it is critical for the survival and incorporation of implanted tissue replacements. While the role of soluble factors in regulating angiogenesis is well established, there is significant interest in uncovering the contributions of cellular interactions with the extracellular matrix (ECM). We chose to study the role of cell-ECM adhesion in regulating angiogenesis, with the hypothesis that quantitative changes in the degree of cell-ECM adhesion ...


Shape Representation In Primate Visual Area 4 And Inferotemporal Cortex, Thomas M. Murphy 2010 University of Pennsylvania

Shape Representation In Primate Visual Area 4 And Inferotemporal Cortex, Thomas M. Murphy

Publicly Accessible Penn Dissertations

The representation of contour shape is an essential component of object recognition, but the cortical mechanisms underlying it are incompletely understood, leaving it a fundamental open question in neuroscience. Such an understanding would be useful theoretically as well as in developing computer vision and Brain-Computer Interface applications. We ask two fundamental questions: “How is contour shape represented in cortex and how can neural models and computer vision algorithms more closely approximate this?” We begin by analyzing the statistics of contour curvature variation and develop a measure of salience based upon the arc length over which it remains within a constrained ...


Unsupervised Classification Of High-Frequency Oscillations In Neocortical Epilepsy And Control Patients, Justin A. Blanco 2010 University of Pennsylvania

Unsupervised Classification Of High-Frequency Oscillations In Neocortical Epilepsy And Control Patients, Justin A. Blanco

Publicly Accessible Penn Dissertations

Quality of life for the more than 15 million people with drug-resistant epilepsy is tied to how precisely the brain areas responsible for generating their seizures can be localized. High-frequency (100-500 Hz) field-potential oscillations (HFOs) are emerging as a candidate biomarker for epileptogenic networks, but quantitative HFO studies are hampered by selection bias arising out of the need to reduce large volumes of data in the absence of capable automated processing methods. In this thesis, I introduce and evaluate an algorithm for the automatic detection and classification of HFOs that can be deployed without human intervention across long, continuous data ...


A Microfabrication Approach To Multicellular Mechanics, Zhijun Liu 2010 University of Pennsylvania

A Microfabrication Approach To Multicellular Mechanics, Zhijun Liu

Publicly Accessible Penn Dissertations

To address the question of how cell-generated forces regulate the organization and function of endothelial cells, I investigated the mechanical forces in a simple model of cell-cell contact: paired cells contacting each other via a single cell-cell junction. To study the responsiveness of AJs to force, I adapted a system of microfabricated force sensors to quantitatively report both the cell-cell tugging force and the size of adherens junctions (AJ). I observed that AJ size was modulated by tugging force: AJs and tugging force grew or decayed with myosin activation or inhibition, respectively. This myosin-dependent regulation operated in concert with a ...


Mechanisms Of Astrocytic Calcium Wave Propagation And In Vitro Hippocampal Cell Death Are Determined By The Magnitude Of Mechanical Injury, William Miller 2010 University of Pennsylvania

Mechanisms Of Astrocytic Calcium Wave Propagation And In Vitro Hippocampal Cell Death Are Determined By The Magnitude Of Mechanical Injury, William Miller

Publicly Accessible Penn Dissertations

It has been estimated that traumatic brain injury (TBI) costs the U.S. economy over $60 billion a year, with over 5.3 million people suffering some level of long term effects. Despite these figures, no effective pharmacological treatment has been successfully developed to help patients recover from TBI. A more complete understanding of both the immediate cellular reactions to injury and the longer-term responses may present new strategies for reducing damage and promoting repair. In this dissertation we first examine the ability for astrocytes to modulate the mechanisms of calcium wave propagation in response to increasing degrees of injury ...


The Design And Validation Of A Novel Computational Simulation Of The Leg For The Investigation Of Injury, Disease, And Surgical Treatment, Joseph Iaquinto 2010 Virginia Commonwealth University

The Design And Validation Of A Novel Computational Simulation Of The Leg For The Investigation Of Injury, Disease, And Surgical Treatment, Joseph Iaquinto

Theses and Dissertations

Computational modeling of joints and their function, a developing field, is becoming a significant health and wellness tool of our modern age. Due to familiarity of prior research focused on the lower extremity, a foot and ankle 3D computational model was created to explore the potential for these computational methods. The method of isolating CT scanned tissue and rendering a patient specific anatomy in the digital domain was accomplished by the use of MIMICS™ , SolidWorks™, and COSMOSMotion™ – all available in the commercial domain. The kinematics of the joints are driven solely by anatomically modeled soft tissue applied to articulating joint ...


Liquid Crystalline Elastomers: Effects Of Substrate Anisotropy On Cell Behavior, Christine DePompeo 2010 Syracuse University

Liquid Crystalline Elastomers: Effects Of Substrate Anisotropy On Cell Behavior, Christine Depompeo

Syracuse University Honors Program Capstone Projects

One of the major challenges in tissue engineering today is inducing organization at the cellular level in vitro. Most biological tissues exhibit anisotropic behavior. They perform differently and have different mechanical properties in different directions. This environment is difficult to mimic with traditional cell culturing methods. The development of anisotropic cell substrates may have the potential to encourage the organization required at the cellular level to induce in vitro tissue formation, an exciting prospect for the advancement of the field of tissue engineering.

It is well known that liquid crystalline elastomers (LCEs) are highly organized polymers with temperature-dependent properties. Previous ...


Waste To Work Using Eccrine Sweat Battery Modules To Enhance Pedestrian Safety, Lauren J. Vesty 2010 Syracuse University

Waste To Work Using Eccrine Sweat Battery Modules To Enhance Pedestrian Safety, Lauren J. Vesty

Syracuse University Honors Program Capstone Projects

There is a need for increased pedestrian visibility. Improved athletic clothing with built in visibility features would enhance a roadside athlete’s safety. This experiment aims to create such an athletic shirt, while incorporating wearable biotechnology. A sweat battery that produced a voltage of 0.49 V and a current of 5.16 mA was created to power the visibility aspects of the shirt. The battery uses an aluminum anode, a carbon cathode, a sponge block as the container and semi-permeable membrane, and the body’s eccrine sweat as the electrolyte solution. The battery cells were arranged into blocks to ...


Electrospun Scaffolds For Directed Pancreatic Differentiation Of Human Ips Cells, Karl Sonntag 2010 University of Arkansas, Fayetteville

Electrospun Scaffolds For Directed Pancreatic Differentiation Of Human Ips Cells, Karl Sonntag

Biological and Agricultural Engineering Undergraduate Honors Theses

In this work, an electrospinning device for fabricating three-dimensional scaffolds was constructed. The device can be used to produce tissue engineered scaffolds electrospun for directing the differentiation of human induced pluripotent stem (iPS) cells into glucose-responsive, insulin-secreting cells for diabetes treatment. Electrospinning utilizes high electrical charge to generate nanofibers from polymers dissolved in solution. A standard setup for such a device includes a high-voltage power source, a syringe pump, and a grounded collector. The process works by dissolving the polymer in a volatile solvent, and filling a syringe with the polymer/solvent mixture. Next, the syringe is locked into place ...


Polymeric Microsensors For Intraoperative Contact Pressure Measurement, Emily R. Pritchard 2010 University of Tennessee, Knoxville

Polymeric Microsensors For Intraoperative Contact Pressure Measurement, Emily R. Pritchard

Doctoral Dissertations

Biocompatible sensors have been demonstrated using traditional microfabrication techniques modified for polymer substrates and utilize only materials suitable for implantation or bodily contact. Sensor arrays for the measurement of the load condition of polyethylene spacers in the total knee arthroplasty (TKA) prosthesis have been developed. Arrays of capacitive sensors are used to determine the three-dimensional strain within the polyethylene prosthesis component. Data from these sensors can be used to give researchers a better understanding of component motion, loading, and wear phenomena for a large range of activities. This dissertation demonstrates both analytically and experimentally the fabrication of these sensor arrays ...


Comparative Studies On Oxygen Mass Transfer For The Design And Development Of A Single-Use Fermentor, Kristan L. Sorenson 2010 Utah State University

Comparative Studies On Oxygen Mass Transfer For The Design And Development Of A Single-Use Fermentor, Kristan L. Sorenson

All Graduate Theses and Dissertations

Accurate experimental oxygen mass transfer coefficient, a measure of how quickly oxygen travels from a gas bubble to the bulk liquid, is important for comparing performance and for evaluating the oxygen transfer capability of a fermentor. Delays in probe response and changing gas volumes upon start-up of gassing affect the accuracy of oxygen transfer measurements. To mitigate these inaccuracies, a standard correction procedure for oxygen mass transfer data was established for highly oxygenated, well-mixed fermentation systems. Probe response time correction was generated by applying a second-order response model to dissolved oxygen probes and shown to be effective within 4%. By ...


Characterization And Physicochemical Modifications Of Polymer Hollow Fiber Membranes For Biomedical And Bioprocessing Applications, Benjamin R. Madsen 2010 Utah State University

Characterization And Physicochemical Modifications Of Polymer Hollow Fiber Membranes For Biomedical And Bioprocessing Applications, Benjamin R. Madsen

All Graduate Theses and Dissertations

Hollow fiber membranes (HFMs) formed through phase inversion methods exhibit specific physicochemical characteristics and generally favorable surface and mechanical properties, supporting their use in diverse applications including ultrafiltration, dialysis, cell culture, bioreactors, and tissue engineering. Characterization of, and modifications to, such membranes are important steps in achieving desired characteristics for specific applications. HFMs subject to gas, irradiation, and chemical sterilization techniques were characterized based on several analytical techniques. It was revealed that these common sterilization techniques can cause inadvertent changes to HFM properties. While these changes may cause detrimental effects to HFMs used in filtration, the methods of sterilization are ...


Using The Continuous Wavelet Transform To Characterize Differences Between Impact Signals From Non-Cleated And Cleated Turf Shoes, Wayne Robert Fischer 2010 Boise State University

Using The Continuous Wavelet Transform To Characterize Differences Between Impact Signals From Non-Cleated And Cleated Turf Shoes, Wayne Robert Fischer

Boise State University Theses and Dissertations

The continuous wavelet transform was used to characterize the time-frequency differences between impact forces from non-cleated and cleated turf shoes among male football athletes who perform cut and run activities. This research is significant because it elucidates how athletes experience different impact force and torque frequency content based on the type of shoe they are wearing. The complex Morlet mother wavelet was used to analyze all ground reaction force and vertical ground reaction moment signals to create time-frequency power spectrum plots. For each signal, a statistical confidence interval was calculated and displayed along with the cone of influence caused by ...


Anaerobic Fermentation Of Hemicellulose Present In Green Liquor And Hot Water Extracts To Carboxylic Acids, Rakhi Reddy Baddam 2010 The University of Maine

Anaerobic Fermentation Of Hemicellulose Present In Green Liquor And Hot Water Extracts To Carboxylic Acids, Rakhi Reddy Baddam

Electronic Theses and Dissertations

Wood is composed of cellulose, hemicellulose and lignin. In the paper industry the cellulose fraction is the major resource used in paper production, whereas the hemicellulose and the lignin are usually burned for heat recovery. Recently, wood-derived hemicellulose extracts have received much attention for the production of valuable bioproduct fuels and chemicals. Mixed-culture microbial ecosystems are capable of converting biomass materials, such as wood extracts, into mixtures of carboxylic acids (C1-C7), which can in turn be purified and sold as products, or converted into other organic chemicals through chemical means. The relative concentrations of the acids produced in the fermentations ...


Quantification Of Regional Pulmonary Blood Flow Parameters Via Multidetector-Row Ct: Evaluation Of Vascular-Based Phenotypes Of Copd, Sara Alford 2010 University of Iowa

Quantification Of Regional Pulmonary Blood Flow Parameters Via Multidetector-Row Ct: Evaluation Of Vascular-Based Phenotypes Of Copd, Sara Alford

Theses and Dissertations

Emphysema, a subset of COPD, occurs due to an abnormal inflammatory response to noxious gases or particles leading an influx of immunologic cells. Recent studies have demonstrated endothelial dysfunction in COPD subjects and are suggestive of a vascular phenotype present in COPD that is not fully characterized. We hypothesize that processes affecting the pulmonary vasculature lead to early changes important in the pathogenesis of COPD. This work focuses on the use of multidetector-row computed tomography (MDCT)-based measures of pulmonary blood flow (PBF), mean transit time (MTT) and pulmonary vascular volume (TPVV) to gain new insights into vasculature-related changes present ...


Quantitative Analysis Of Retinal Function In Early Stages Of Retinal Degeneration In The Rd1 Mouse, Erik Lee Nylen 2010 University of Iowa

Quantitative Analysis Of Retinal Function In Early Stages Of Retinal Degeneration In The Rd1 Mouse, Erik Lee Nylen

Theses and Dissertations

In this thesis, I use a range of techniques in computational neuroscience, communication theory, and electrophysiology to characterize functional changes that occur in early stages of retinal degeneration in the mouse. At post natal day 14, retinal ganglion cells in the rd1 mouse exhibit peculiar differences from age matched controls: an increased latency of responses to the onset of a light stimulus, decreased spike count in response to stimulus onset, increased spontaneous firing activity, and a decrease in information transmission. I propose this is due to an up-regulation of OFF bipolar cell excitation, a critical factor in functional changes seen ...


A Synthetic Biological Engineering Approach To Secretion- Based Recovery Of Polyhydroxyalkanoates And Other Cellular Products, Elisabeth Linton 2010 Utah State University

A Synthetic Biological Engineering Approach To Secretion- Based Recovery Of Polyhydroxyalkanoates And Other Cellular Products, Elisabeth Linton

All Graduate Theses and Dissertations

The costs associated with cellular product recovery commonly account for as much as 80% of the total production expense. As a specific example, significant recovery costs limit commercial use of polyhydroxyalkanoates (PHA), which comprise a class of microbially-accumulated polyesters. PHAs are biodegradable compounds that are of interest as a sustainable alternative to petrochemically-derived plastics. Secretion-based recovery of PHAs was studied to decrease PHA production costs. Type I and II secretory pathways are commonly used for the translocation of recombinant proteins out of the cytoplasm of E. coli. Proteins were targeted for translocation using four signal peptides (HlyA, TorA, GeneIII, and ...


Investigation Of Local Deformation Of The Median Nerve In Magnetic Resonance Images Of The Carpal Tunnel, Nicole Marie Kunze 2010 University of Iowa

Investigation Of Local Deformation Of The Median Nerve In Magnetic Resonance Images Of The Carpal Tunnel, Nicole Marie Kunze

Theses and Dissertations

As the incidence of diagnosed carpal tunnel syndrome continues to increase, an understanding of the mechanism(s) of insult to the median nerve which leads to its development becomes ever more imperative. Knowledge of the exact cause of CTS could lead to improved diagnostic and treatment methods, or more importantly, to better preventative measures. The goal of this study was to investigate movements and interactions of structures within the carpal tunnel during wrist flexion and hand loading in order to obtain information about a specific mechanism of insult to the median nerve. Symptomatic and normal subjects were compared to observe ...


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