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Theses/Dissertations

2010

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Full-Text Articles in Biomedical Engineering and Bioengineering

Modeling Of Equilibrium Point Trajectory Control In Human Arm Movements, Kai Chen Dec 2010

Modeling Of Equilibrium Point Trajectory Control In Human Arm Movements, Kai Chen

Dissertations

The underlying concept of the Equilibrium Point Hypothesis (EPH) is that the CNS provides a virtual trajectory of joint motion, representing spacing and timing, with actual movement dynamics being produced by interactions of limb inertia, muscle viscosity and speed/position feedback from muscle spindles. To counter criticisms of the EPH, investigators have proposed the use of complex virtual trajectories, non-linear damping, stiffness and time varying stiffness to the EPH model. While these features allow the EPH to adequately produce human joint velocities, they conflict with the EPH’s premise of simple pre-planned monotonic control of movement trajectory. As a result ...


Development Of A Centrifugal Microfluidic Device For Separation And Sorting In Biological Fluids, Gaurav Sunil Bagwe Dec 2010

Development Of A Centrifugal Microfluidic Device For Separation And Sorting In Biological Fluids, Gaurav Sunil Bagwe

Theses

A wide interest in employing micron-scale, integrated biochemical analysis systems for economical and rapid diagnosis has been the principal motivation behind this project. Low operating costs, portability and fast diagnosis times make centrifugal microfluidic devices an attractive option in patient-side diagnostics. Some essential tasks to be performed in microfluidic devices are sample-reagent transport, mixing, separation and detection. All these tasks require precise control of the RPM and spinning time. Centrifugal micro-fluidic platforms have been successfully implemented for detection of hepatitis A, tetanus, as well as for measurement of haemoglobin and hematocrit, for DNA analysis, and for assessment of cardiac disease ...


Non-Invasive Interventions Top Reduce Low Back Dysfunction, Nadi Atalla Dec 2010

Non-Invasive Interventions Top Reduce Low Back Dysfunction, Nadi Atalla

Theses

This study aims to quantitatively evaluate the low back condition so that low back dysfunction can be identified and classified when measurements show a variance from the normal. The evaluation is done by using the hysteresis concept. In this study, subjects received two different types of treatment: massaging using a mechanical massager for ten minutes and manual massaging by a professional physician. Using the Automated Anatomic Torsion Monitor (A-ATM), the low back of the subject was evaluated before and after treatment. The change in Hysteresis Loop Area (HLA) was -12.5% for mechanical massaging and -15.7% for manual massaging ...


Effects Of Hypertension And Aging On Vascular Smooth Muscle Cell Contribution To Reconstituted Aortic Tissue Stiffness, Nancy Lisa Sehgel Dec 2010

Effects Of Hypertension And Aging On Vascular Smooth Muscle Cell Contribution To Reconstituted Aortic Tissue Stiffness, Nancy Lisa Sehgel

Theses

Aortic stiffness increases with hypertension and aging, and much of this increase has been thought to occur due to changes in the extracellular matrix. However, an increase in cell stiffness could also be important. To study the cellular contribution to aortic stiffness, a reconstituted aortic tissue model (composed of vascular smooth muscle cells (VSMCs) in a collagen matrix) was developed. VSMCs isolated from thoracic aortic samples of 5-week and 18-week old male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were passaged four times and then separately incubated in collagen for two days on a cylindrical mandrel. The resulting ...


Motor Planning For Reach Memorization Task In 3d Space, Atul Narkhede Dec 2010

Motor Planning For Reach Memorization Task In 3d Space, Atul Narkhede

Theses

Arm reaching towards remembered targets in three-dimensional space was analyzed. The aim of the project was to test whether various amounts of visual feedback, in combination with constant forces applied to the arm during reaching would affect the magnitude and direction of the reaching errors. The robotic arm (Haptic Master, Moog Inc) recorded the spatial position of the pointer attached to its end effector, thus tracking the movement of the subject's arm. Three haptically rendered targets at different points in space were presented to the subjects using stereo virtual environment. The simulation was programmed using Visual C++ and OpenGL ...


Emg-Based Determination Of Upper Extremity Virtual Trajectory, Akshata Anand Korgaonkar Dec 2010

Emg-Based Determination Of Upper Extremity Virtual Trajectory, Akshata Anand Korgaonkar

Theses

Movement and position of the limbs of the human body are controlled by the interaction between the muscle and the peripheral and central nervous system. This interaction is nothing but the neural signals. Neural signals are electrical in nature and referred as action potentials. An EMG is a summation of action potentials from the muscle fibers under the electrode placed on the skin. Thus it is easy to estimate the nature and timing of the movement from the firing of an EMG signal. Kai Chen in his dissertation has built the model to represent the arm movement with stiffness, damping ...


Tilt Simulation : Virtual Reality Based Upper Extremity Stroke Rehabilitation, Harish Damodaran Dec 2010

Tilt Simulation : Virtual Reality Based Upper Extremity Stroke Rehabilitation, Harish Damodaran

Theses

The primary objective of this research is to design a recreational rehabilitation videogame that interactively encourages purposeful upper extremity gross motor movements. The simulation is also capable of continuous game modification to fit changing therapy goals, to match the needs of the players, and to provide continued motivation while capturing the interactive repetition. This thesis explains the design and features of this latest simulation - Tilt. Tilt uses physics to develop an engaging training experience and provides a realistic approach to virtual reality simulation including friction, elasticity and collisions between objects. It is designed to train upper extremity function as a ...


Mapping Trabecular Bone Fabric Tensor By In Vivo Magnetic Resonance Imaging, Michael J. Wald Dec 2010

Mapping Trabecular Bone Fabric Tensor By In Vivo Magnetic Resonance Imaging, Michael J. Wald

Publicly Accessible Penn Dissertations

The mechanical competence of bone depends upon its quantity, structural arrangement, and chemical composition. Assessment of these factors is important for the evaluation of bone integrity, particularly as the skeleton remodels according to external (e.g. mechanical loading) and internal (e.g. hormonal changes) stimuli. Micro magnetic resonance imaging (µMRI) has emerged as a non-invasive and non-ionizing method well-suited for the repeated measurements necessary for monitoring changes in bone integrity. However, in vivo image-based directional dependence of trabecular bone (TB) has not been linked to mechanical competence or fracture risk despite the existence of convincing ex vivo evidence. The objective ...


Computational Modeling Of Protein Kinases: Molecular Basis For Inhibition And Catalysis, Yingting Liu Dec 2010

Computational Modeling Of Protein Kinases: Molecular Basis For Inhibition And Catalysis, Yingting Liu

Publicly Accessible Penn Dissertations

Protein kinases catalyze protein phosphorylation reactions, i.e. the transfer of the γ-phosphoryl group of ATP to tyrosine, serine and threonine residues of protein substrates. This phosphorylation plays an important role in regulating various cellular processes. Deregulation of many kinases is directly linked to cancer development and the protein kinase family is one of the most important targets in current cancer therapy regimens. This relevance to disease has stimulated intensive efforts in the biomedical research community to understand their catalytic mechanisms, discern their cellular functions, and discover inhibitors. With the advantage of being able to simultaneously define structural as well ...


The Development, Characterization And Implementation Of A Reactive Oxygen Species-Responsive Ratiometric Bioluminescent Reporter And Its Use As A Sensor For Programmed Cell Death, Julie Czupryna Dec 2010

The Development, Characterization And Implementation Of A Reactive Oxygen Species-Responsive Ratiometric Bioluminescent Reporter And Its Use As A Sensor For Programmed Cell Death, Julie Czupryna

Publicly Accessible Penn Dissertations

The process of programmed cell death (PCD) is a prevalent area of scientific research and is characterized by a highly complex proteolytic cascade. PCD is involved in development, homeostasis and the immune response. Further, unregulated PCD has been implicated in various, often, devastating pathologies including cancer, autoimmune diseases and neurodegenerative disorders. The importance of PCD in human health and disease has led to the widespread utilization of genetically encoded reporters for the non-invasive imaging of PCD in vitro and in vivo; however, it is currently not well understood whether the reporters themselves are susceptible to inactivation and/or degradation during ...


Rac1-Mediated Actin Cytoskeleton Remodeling And Monolayer Barrier Properties Of Stretched Alveolar Epithelial Cells, Brian Christopher Dipaolo Dec 2010

Rac1-Mediated Actin Cytoskeleton Remodeling And Monolayer Barrier Properties Of Stretched Alveolar Epithelial Cells, Brian Christopher Dipaolo

Publicly Accessible Penn Dissertations

Mechanical ventilation is vital for supporting patients with pulmonary insufficiency. However, experimental data suggests that pulmonary injury can occur during mechanical ventilation as a result of elevated regional lung volumes resulting in excessive alveolar epithelial cell (AEC) stretch due to basement membrane deformation and reduced barrier function.

AECs maintain integrity of the blood-gas barrier with gasket like intercellular tight junctions (TJ) which are anchored internally to the actin cytoskeleton. Our goal was to evaluate the effect of physiologically relevant, high magnitude biaxial stretch on the actin cytoskeleton, a principal regulator of monolayer barrier properties, as a foundation to develop strategies ...


Integrating Electrophysiological, Mechanical, And Optical Methods To Define The Mechanisms Of Painful Facet Joint Injury, Kyle P. Quinn Dec 2010

Integrating Electrophysiological, Mechanical, And Optical Methods To Define The Mechanisms Of Painful Facet Joint Injury, Kyle P. Quinn

Publicly Accessible Penn Dissertations

Persistent pain is a common occurrence following whiplash injuries produced during motor vehicle crashes. The cervical facet joint and its capsule have often been identified as the source of chronic pain in patients with whiplash-associated disorders. However, for the majority of patients, no radiographic evidence of cervical spine injury is present. A capsular ligament stretch-based mechanism for initiating facet-mediated pain has been proposed based on human cadaveric studies of the facet joint kinematics during whiplash stimulations. However, without direct evidence of capsule damage during whiplash, the biomechanical and physiological mechanisms by which altered vertebral kinematics produce a facet capsule injury ...


Development As A New Paradigm For Improved Tendon Healing: A Characterization Of Neonatal Tendon Development, Healing During Development And An Investigation Into Differential Parameters During Accelerated Healing, Heather L. Ansorge Dec 2010

Development As A New Paradigm For Improved Tendon Healing: A Characterization Of Neonatal Tendon Development, Healing During Development And An Investigation Into Differential Parameters During Accelerated Healing, Heather L. Ansorge

Publicly Accessible Penn Dissertations

During neonatal development, tendons undergo a well orchestrated process whereby extensive structural and compositional changes occur in synchrony to produce a normal tissue. Conversely, during the repair response to injury, structural and compositional changes occur, but in this case, a mechanically inferior tendon is produced. An injured tendon that is mechanically inferior has compromised function and reruptures after treatment are commonly observed clinically. As a result, the process of development has been postulated as a potential paradigm through which improved adult tissue healing may occur. First, the role of CD44 in healing was examined through a patellar tendon injury in ...


Mammary Epithelial Metastatic Phenotype Forced Through The Extracellular Matrix, Olga Shebanova Dec 2010

Mammary Epithelial Metastatic Phenotype Forced Through The Extracellular Matrix, Olga Shebanova

Publicly Accessible Penn Dissertations

Biochemical and mechanical cues of the extracellular matrix have been shown to play important roles in cell-matrix and cell-cell interactions. We have experimentally tested the combined influence of these cues on cell motility, cell-cell interaction and assembly and traction force profile in an in vitro breast cancer model. The behavior of non-tumorigenic mammary epithelial cells was observed on surfaces with varying ligand concentration and polyacrylamide gel rigidity. Our data shows that cell velocity is biphasic in both matrix rigidity and adhesiveness, which are inversely related. Traction force microscopy revealed that maximum migration velocity is reached at intermediate force of single ...


Dendritic Cell Migration And Traction Force Generation In Engineered Microenvironments, Brendon Guenther Ricart Dec 2010

Dendritic Cell Migration And Traction Force Generation In Engineered Microenvironments, Brendon Guenther Ricart

Publicly Accessible Penn Dissertations

Dendritic cells (DCs) are potent initiators of the adaptive immune response. Their trafficking from sites of inflammation to lymphoid tissue is essential to their function. Exactly how dendritic cells integrate multiple chemotactic cues to organize an accurate migratory path is not fully understood. We first characterize DC random motility (chemokinesis) on extracellular matrix proteins in the presence of chemokines. Then, using a microfluidic device, we present both single and competing chemokine gradients to murine bone-marrow derived DCs in a controlled, time-invariant microenvironment. We show that in counter gradients, CCL19 is 10 to 100 fold more potent than other chemokines CCL21 ...


Development Of A Rigid Body Computational Model For Investigation Of Wrist Biomechanics, Benjamin Majors Dec 2010

Development Of A Rigid Body Computational Model For Investigation Of Wrist Biomechanics, Benjamin Majors

Theses and Dissertations

The wrist is one of the most complex joints in the human body. As such, the wrist joint is difficult to model due to the number of bones involved and its intricate soft tissue interactions. Many studies have attempted modeling the wrist previously; however, the majority of these studies simplify the joint into two-dimensions or idealized mechanical joints to reduce the complexity of the simulation. While these approaches still yield valuable information, the omission of a third-dimension or geometry defined movements limits the models’ usefulness in predicting joint function under non-idealized conditions. Therefore, the goal of this study was to ...


Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade Dec 2010

Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade

Electronic Thesis and Dissertation Repository

In the ongoing quest to extract more information from MRI images, there has arisen a need to rapidly map the flip angle. This has been primarily driven by the shift to stronger main field strengths, which bring with them improved SNR, but also new difficulties. In particular, the radio frequency field used to excite the magnetization can no longer be assumed uniform at field strengths of 3 Tesla and above. New rapid quantitative imaging techniques, such as DESPOT1 and DESPOT2, rely on accurate knowledge of the flip angle, and while this could safely be assumed to be the prescribed value ...


Modeling Of Aortic Valve Anatomic Geometry From Clinical Multi Detector-Row Computed Tomography Images, Gregory A. Book Dec 2010

Modeling Of Aortic Valve Anatomic Geometry From Clinical Multi Detector-Row Computed Tomography Images, Gregory A. Book

Master's Theses

Transcatheter aortic valve implantation (TAVI) is an emerging and viable alternative to surgical valve replacement. A TAVI procedure involves insertion of a catheter into the heart through an artery or transapically, and expanding valve stent in place. This procedure dramatically reduces the recovery time by eliminating the need for open heart surgery. Understanding the biomechanics of the stent-valve interaction is crucial for proper device deployment and function. In this study, we examine the extraction of valve geometries and creation of valve models from multi-detector row computed tomography (MDCT) images that may eventually be used to model stent expansion on a ...


4-D Modeling Of Displacement Vector Fields For Improved Radiation Therapy, Elizabeth Zachariah Dec 2010

4-D Modeling Of Displacement Vector Fields For Improved Radiation Therapy, Elizabeth Zachariah

Theses and Dissertations

In radiation therapy, it is imperative to deliver high doses of radiation to the tumor while reducing radiation to the healthy tissue. Respiratory motion is the most significant source of errors during treatment. Therefore, it is essential to accurately model respiratory motion for precise and effective radiation delivery. Many approaches exist to account for respiratory motion, such as controlled breath hold and respiratory gating, and they have been relatively successful. They still present many drawbacks. Thus, research has been expanded to tumor tracking. This paper presents a spatio-temporal model for four dimensional CT reconstruction. The method begins with a set ...


Synthesis And Characterization Of Electrospun Gelatin/Dendrimer Scaffold Encapsulated With A Silver As A Potential Antimicrobial Wound Dressing, Alpana Dongargaonkar Dec 2010

Synthesis And Characterization Of Electrospun Gelatin/Dendrimer Scaffold Encapsulated With A Silver As A Potential Antimicrobial Wound Dressing, Alpana Dongargaonkar

Theses and Dissertations

A novel nanofiber scaffold was fabricated and characterized as a potential antimicrobial wound dressing. Half generation polyamidoamine (PAMAM) dendrimer G3.5 was covalently conjugated to gelatin. Gelatin alone or with gelatin-dendrimer conjugates was electrospun into nanofiber scaffolds. Gelatin is a derivative of natural collagen, and it is biocompatible, non-toxic and inexpensive, making it a desirable component in a wound dressing. Dendrimers are synthetic polymers comprising of a central core, internal branches and reactive surface groups. They provide a structurally controlled architecture for drug release. Silver was incorporated into the scaffold in situ due to its broad spectrum of antimicrobial properties ...


Development Of Electroencephalography Based Brain Controlled Switch And Nerve Conduction Study Simulator Software, Kai Qian Dec 2010

Development Of Electroencephalography Based Brain Controlled Switch And Nerve Conduction Study Simulator Software, Kai Qian

Theses and Dissertations

This thesis investigated the development of an EEG-based brain controlled switch and the design of a software for nerve conduction study. For EEG-based brain controlled switch, we proposed a novel paradigm for an online brain-controlled switch based on Event-Related Synchronizations (ERDs) following external sync signals. Furthermore, the ERD feature was enhanced by 3 event-related moving averages and the performance was tested online. Subjects were instructed to perform an intended motor task following an external sync signal in order to turn on a virtual switch. Meanwhile, the beta-band (16-20Hz) relative ERD power (ERD in reverse value order) of a single EEG ...


New Tools For Monitoring Gamma Camera Uniformity, Brad K. Lofton Dec 2010

New Tools For Monitoring Gamma Camera Uniformity, Brad K. Lofton

UT GSBS Dissertations and Theses (Open Access)

Detector uniformity is a fundamental performance characteristic of all modern gamma camera systems, and ensuring a stable, uniform detector response is critical for maintaining clinical images that are free of artifact. For these reasons, the assessment of detector uniformity is one of the most common activities associated with a successful clinical quality assurance program in gamma camera imaging. The evaluation of this parameter, however, is often unclear because it is highly dependent upon acquisition conditions, reviewer expertise, and the application of somewhat arbitrary limits that do not characterize the spatial location of the non-uniformities. Furthermore, as the goal of any ...


An Animal Model For Discogenic Low Back Pain, Candis Schrelle Dubose Dec 2010

An Animal Model For Discogenic Low Back Pain, Candis Schrelle Dubose

Theses and Dissertations

Low back pain is a debilitating condition that afflicts millions of people each year. It is characterized by complex biochemical, morphological, and biomechanical changes. However, most believe low back pain arises due to abnormal mechanical loading, inflammation, and disc degeneration. Several studies have investigated radial back pain, but to date, there is only one in vivo animal model for low back pain. Despite advances in science, the causes of low back pain remain unclear and treatments fail to relieve the pain. To better understand the causative factors of low back pain, a reliable animal model is needed. This study was ...


Model Predictive Control For Adaptive Digital Human Modeling, Katha Janak Sheth Dec 2010

Model Predictive Control For Adaptive Digital Human Modeling, Katha Janak Sheth

Theses and Dissertations

We consider a new approach to digital human simulation, using Model Predictive Control (MPC). This approach permits a virtual human to react online to unanticipated disturbances that occur in the course of performing a task. In particular, we predict the motion of a virtual human in response to two different types of real world disturbances: impulsive and sustained. This stands in contrast to prior approaches where all such disturbances need to be known a priori and the optimal reactions must be computed off line. We validate this approach using a planar 3 degrees of freedom serial chain mechanism to imitate ...


Cfd Study On Effect Of Branch Sizes In Human Coronary Artery, Liza Shrestha Dec 2010

Cfd Study On Effect Of Branch Sizes In Human Coronary Artery, Liza Shrestha

Theses and Dissertations

Atherosclerosis is a term coined to describe a state in which arterial wall thickens due to the accumulation of fatty materials like cholesterol. Though not completely understood, it is believed to occur due to the accumulation of macrophage white blood cells and promoted by low density lipoprotein. Increase in accumulation of plaque leads to enlargement of arteries as arterial wall tries to remodel itself. But eventually the plaque ruptures, letting out its inner content to blood stream. The ruptured plaque clots and heals and shrinks down as well but leaves behind stenosis - narrowing of cross section. Depending on the degree ...


Airway Segmentation Of The Ex-Vivo Mouse Lung Volume Using Voxel Based Classification, Tarunashree Yavarna Dec 2010

Airway Segmentation Of The Ex-Vivo Mouse Lung Volume Using Voxel Based Classification, Tarunashree Yavarna

Theses and Dissertations

The spread of the pulmonary disease among humans is a very rapid process and it stands as the third highest killer in the United States of America. Computed Tomography (CT) scanning allows us to obtain detailed images of the pulmonary anatomy including the airways. The complexity of the tree makes the process of manual segmentation tedious, time-consuming, and variant across individuals. The resultant airway segmentation, whether arrived at manually or through the aid of computers, can then be used to measure airway geometry, study airway reactivity, and guide surgical interventions.

The thesis addresses these problems and suggests a fully automated ...


Segmentation Of Lung Tissue In Ct Images With Disease And Pathology, Panfang Hua Dec 2010

Segmentation Of Lung Tissue In Ct Images With Disease And Pathology, Panfang Hua

Theses and Dissertations

Lung segmentation is an important first step for quantitative lung CT image analysis and computer aided diagnosis. However, accurate and automated lung CT image segmentation may be made difficult by the presence of the abnormalities. Since many lung diseases change tissue density, resulting in intensity changes in CT image data, intensity-only segmentation algorithms will not work for most pathological lung cases. This thesis presents two automatic algorithms for pathological lung segmentation. One is based on the geodesic active contour, another method uses graph search driven by a cost function combining the intensity, gradient, boundary smoothness, and the rib information. The ...


Virtual Pre-Operative Reconstruction Planning For Comminuted Articular Fractures, Thaddeus Paul Thomas Dec 2010

Virtual Pre-Operative Reconstruction Planning For Comminuted Articular Fractures, Thaddeus Paul Thomas

Theses and Dissertations

Highly comminuted intra-articular fractures are complex and difficult injuries to treat. Once emergent care is rendered, the definitive treatment objective is to restore the original anatomy while minimizing surgically induced trauma. Operations that use limited or percutaneous approaches help preserve tissue vitality, but reduced visibility makes reconstruction more difficult. A pre-operative plan of how comminuted fragments would best be re-positioned to restore anatomy helps in executing a successful reduction. The objective of this work was to create new virtual fracture reconstruction technologies that would deliver that information for a clinical series of severe intra-articular fractures. As a step toward clinical ...


An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong Dec 2010

An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong

Biomedical Engineering

No abstract provided.


Characterization And Analysis Techniques Of A Dynamic In Vitro Blood-Brain Barrier Model, Ryan Everett Woodhouse Dec 2010

Characterization And Analysis Techniques Of A Dynamic In Vitro Blood-Brain Barrier Model, Ryan Everett Woodhouse

Biomedical Engineering

The blood-brain barrier (BBB) is responsible for maintaining the sensitive environment required by the brain. Although the BBB is necessary for proper functioning of the brain, it acts as an obstacle for doctors attempting to treat neurological disease. For a drug to act upon the brain, it must first pass through the discriminating BBB. For this reason, much research has been performed in recent years in order to create an in vitro model of the BBB on which drugs targeted for the central nervous system may be tested. The main goal of this project is to create an in vitro ...