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Theses/Dissertations

2004

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Articles 1 - 30 of 37

Full-Text Articles in Biomedical Engineering and Bioengineering

Labview Controlled Study Of The Propagation Properties Of Ultrasound In Synthetic Fog Environment, Aparna Venkataraman Dec 2004

Labview Controlled Study Of The Propagation Properties Of Ultrasound In Synthetic Fog Environment, Aparna Venkataraman

Theses

Diagnostic ultrasound employs pulsed, high frequency sound waves that are reflected back from body tissues and processed by ultrasound receivers to create characteristic images in varied applications such as cardiology, obstetrics and gynecology neurology and urology. Ultrasound intensity is primarily affected by the changes in acoustic impedance of the medium. Literature on ultrasound indicates that the propagation of ultrasound increases gradually as the density increases from air to water. Such studies have been confined to only the three states of matter and have never discussed a fog medium.

The primary objective of this thesis study was to design a system ...


Parameter Based Synthesis Of Sign Language, Amanda Irving Dec 2004

Parameter Based Synthesis Of Sign Language, Amanda Irving

Theses

The primary objective of this project is to demonstrate synthesis of signs in American Sign Language with a finite number of parameters. The parameters in this method include 22 key locations, six location modifiers, six orientation indicators, 46 hand shapes, six predefined movements and seven possible end effectors. These parameters can be used in conjunction with a computer script and they maximize precision and versatility while minimizing development time and resources. The parameters for each sign are stored in an individual text file averaging approximately half a kilobyte.

The success of this project is demonstrated using UGS's Jack Software ...


Electrospinning Of Biphasic Biopolymer And Polymer : A Feasibility And Characterization Study, Sherry Hsiu-Ying Wang Dec 2004

Electrospinning Of Biphasic Biopolymer And Polymer : A Feasibility And Characterization Study, Sherry Hsiu-Ying Wang

Theses

Electrospinning of polymeric materials have been experimented to achieve nanoscaled diameters. The approaches to the current study are to combine a natural material such as collagen with synthetic materials and determine if the interactions between the materials can be used in the electrospinning process. Collagen is a material of choice due to its biocompatibility. When collagen is combined with polymer, Polyethylene Oxide (PEG), the fiber diameters ranged from 150nm to one micron. The fibers produced have shown drastic phase separation. The next study involved using a duel solvent system to electrospin fibers. The polymer of choice is Poly (1-lactic acid ...


Obtaining Optimal Data Length For Fmri Images, Vikram M. Natarajan Dec 2004

Obtaining Optimal Data Length For Fmri Images, Vikram M. Natarajan

Theses

Interest in brain hemodynamics has led to a substantial increase in state of the art research within the field of functional Magnetic Resonance Imaging (fMRI). FMRI enables research to be conducted on brain mapping in healthy individuals, as well as in patient populations. The need for accurate functional images is required. The primary objective was the development of a method to determine the optimal number of time points required to obtain reliable activation maps. The second phase involved the development of a program, which enabled the conversion of functional magnetic resonance images to a format that the neurosurgeon's scanner ...


Ambulatory Measurement Of Body Position, Swetha Vennamaneni Dec 2004

Ambulatory Measurement Of Body Position, Swetha Vennamaneni

Theses

Ambulatory monitoring is playing an important role in the clinical and research field. In the modem era, physicians are showing much interest in measuring heart rate, blood pressure and many other physical and cardiac conditions and recording electrocardiogram (ECG, a popular technique for diagnosing heart related disease), while the patient is ambulatory. Heart rate, blood pressure and ECG waveform can change because of body position. In the case of the ECG, the changes caused by body position are can change the ST-T segment and also the QRS amplitude. The heart rate and blood pressure changes when there is a change ...


Biomimetic Synthesis Within Polyelectrolyte Microcapsules: Characterization Of Enzyme Catalyzed Polyphenols And Polypeptides, Rohit C. Ghan Oct 2004

Biomimetic Synthesis Within Polyelectrolyte Microcapsules: Characterization Of Enzyme Catalyzed Polyphenols And Polypeptides, Rohit C. Ghan

Doctoral Dissertations

An enzyme-catalyzed synthesis of novel polymers within layer-by-layer (LbL) constructed polyelectrolyte microcapsules has been developed. This approach is based on the selective permeability of polyelectrolyte-capsule walls to monomer molecules. Conversely biocatalysts and forming polymeric chains cannot exit the micro-capsule interior because of their characteristic high molecular weight. Horseradish Peroxidase (HRP) was encapsulated into four bilayer PSS (poly-styrenesulfonate)/PAH (poly-allylamine hydrochloride) capsules with an average diameter of 5 μm using pH-driven pore opening. The polymerization of 4-(2-Aminoethyl) phenol hydrochloride (tyramine) catalyzed by HRP produces easily detectable fluorescent polymeric products after the addition of hydrogen peroxide to the system. It is ...


Characterization Of Mechanical Behavior Of Electrospun Non-Woven Mats, Ajitha Patlolla Aug 2004

Characterization Of Mechanical Behavior Of Electrospun Non-Woven Mats, Ajitha Patlolla

Theses

Electrospinning is a simple and efficient method for the production of nanometer to micrometer fibers. While the process of electrospinning has been known for over half a century, current understanding of the process and those parameters that affect the properties of the fibers is very limited. Not much work has been done in the field electrospinning process to study the mechanical properties of nonwoven mats produced and to study parameters affecting their properties.

In the first part of this thesis electrospun nonwoven mats made of poly(lactides) solutions were characterized based on their mechanical behavior in biorelevant conditions. In the ...


Thermal Analysis Of Poly(Desamino Arylates), Ali Cem Recber Aug 2004

Thermal Analysis Of Poly(Desamino Arylates), Ali Cem Recber

Theses

The goal of this study is to better understand the thermal characteristics and molecular behavior of two poly(desaminotyrosyl arylates). These two polymers were chosen from a combinatorial library of polymers developed by changing the type and size of the two substitutable chain locations. TGA, DSC and TSC studies were conducted on Poly(12,10) and Poly(2,2) after the samples were exposed to various conditions. The TGA of Poly(12,10) shows low water uptake at 25° C, higher water uptake at 80°C. Water uptake for Poly(2,2) at 25°C is similar to Poly(12 ...


A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu Jul 2004

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single ...


Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue Jul 2004

Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue

Mechanical & Aerospace Engineering Theses & Dissertations

Naturally nanofluidics has applications demanding the samples to be handled in exceedingly small quantities due to the small size of the fluidic channels in nanofluidic devices, such as characterization of single biomolecules. Fluids confined in channels of nanometer characteristic dimensions exhibit physical behaviors not observed in large conduits. Charge properties of the nanochannel wall in contact with an aqueous solution play essential roles in the involved electrokinetic transport phenomena occurring in nanofluidic devices. In addition to tuning the charge properties of the nanofluidic channel wall by adjusting the solution properties such as pH and background salt concentration, field effect transistor ...


Parametric Synthesis Of Sign Language, Jerome Allen May 2004

Parametric Synthesis Of Sign Language, Jerome Allen

Theses

The isolation of the deaf community from mainstream society is in part due to the lack of knowledge most hearing people have of sign language. To most, there seems to be little need to learn a language that is spoken by such a small minority unless perhaps a relative is unable to hear. Even with a desire to learn, the task may seem insurmountable due to the unique formational and grammatical rules of the language.

This linguistic rift has led to the call for an automatic translation system with the ability to take voice or written text as input and ...


Spinning Of Collagen Fibers And Characterizing Thermal, Mechanical, Tensile And Structural Properties, Grace Evangelin Tatagiri May 2004

Spinning Of Collagen Fibers And Characterizing Thermal, Mechanical, Tensile And Structural Properties, Grace Evangelin Tatagiri

Theses

Collagen is the most important building block in the entire animal world. It plays an important role in regeneration of broken bones and wound healing, also helps grow blood vessels to feed the healing areas. The use of synthetic materials has been extensive, but these materials have there own limits and drawbacks. Poor biocompatibility of these materials is the main issue and often result in inflammations. Hence collagen is being heralded as one of the most appropriate replacement as an implantable material. The reasons being that it is a naturally occurring material, exhibits high biocompatibility low antigenicity and host response ...


Measurement Of The Effectiveness Of Enhanced External Counterpulsation On Heart Rate Variability For Patients With Myocardial Ischemia, Kripa Jayaraman May 2004

Measurement Of The Effectiveness Of Enhanced External Counterpulsation On Heart Rate Variability For Patients With Myocardial Ischemia, Kripa Jayaraman

Theses

This thesis is a study to measure the changes in heart rate variability due to the activity of the autonomic nervous system caused by the Enhanced External Counterpulsation treatment. The treatment is a non surgical, mechanical procedure that can reduce the symptoms of angina or Congestive Heart Failure, presumably by stimulating the opening, or formation of, small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries. It has been proved that rhythms can be markers of normal functional states. Even in the absence of external perturbations, the normal heartbeat is not characterized by clockwise ...


Biomimetic Sensor For In-Vivo Applications, Daya I. Sooryadas May 2004

Biomimetic Sensor For In-Vivo Applications, Daya I. Sooryadas

Theses

The development of sensitive specific devices (e.g., molecular sensors) for the detection, diagnosis and monitoring of diseases, drug discovery, environmental detection of pollutants and/or biological agents has been an active area of research. A molecular sensor is a biomolecule or biomimetic molecule that performs two distinct functions in detecting target molecules. The sensor molecule recognizes a target molecule and specifically binds to it. This specific binding generates a signal in response to the event of target binding that can be then detected. The long term vision of this thesis research work is to develop a specific recognition ligand ...


Design And Implementation Of Heart Rate Variability Measures In The Time Domain, Binoy John Mathews May 2004

Design And Implementation Of Heart Rate Variability Measures In The Time Domain, Binoy John Mathews

Theses

The following study was conducted to design and implement computer programs to derive five time domain and two frequency domain Heart Rate Variability (HRV) measures from 24 hour Holter monitor recordings and to generate activity plots that display the variation of three of the five time domain measures and two frequency domain measures over a period of 24 hours.

Working with known pre and post experimental ECG data taken from a cyclical exercise program, standard parameters in both the time and frequency domains were derived using programs designed in Labview 7.0 engineering software package. Five parameters in the time ...


An Investigation Of Position And Force During Gait-Mimicking Finger Motions, Matthew Stephen Noesner May 2004

An Investigation Of Position And Force During Gait-Mimicking Finger Motions, Matthew Stephen Noesner

Theses

Spinal cord injuries are extremely debilitating, often leaving the injured person without the ability to use their legs (paraplegia) and sometimes, without the ability to use their arms and legs (tetraplegia or quadriplegia). Currently, primitive forms of feed-forward functional electrical stimulation (FES) and special orthotics are available for persons with paraplegia. However, these forms of FES do not allow the individual to actually control their movements on a real-time basis, nor do they offer the ability for the injured person to sense the ground on which they stand.

It is the goal of the researchers at the Neuromuscular Engineering Laboratory ...


Extending The Boundary Method For Solving Human Motion Problems Using A 3 Dimensional Coupled Pendulum Model, Avani Janardan Patel May 2004

Extending The Boundary Method For Solving Human Motion Problems Using A 3 Dimensional Coupled Pendulum Model, Avani Janardan Patel

Theses

Mathematical modeling, an evolving area in movement analysis research, couples quantitative measures of human motion with theoretical concepts in physiology and mechanics. Literature reveals two methods to solve for human motion problems, Forward and Inverse Mechanics. In this investigation, a new approach called the Boundaty Method is adopted to solve for human motion. This approach has the advantage of being able to solve for both new motions and the net muscular joint forces required to produce those motions but only at those discrete times and body configurations that are believed to be most crucial for accomplishing the task.

The method ...


Extrusion And Evaluation Of Degradation Rate And Porosity Of Small Diameter Collagen Tubes, Bipinkumar G. Patel May 2004

Extrusion And Evaluation Of Degradation Rate And Porosity Of Small Diameter Collagen Tubes, Bipinkumar G. Patel

Theses

The limited availability of autografts and failure of small diameter synthetic vascular grafts has stimulated continuing efforts to develop small diameter vascular grafts based on natural materials. The small diameter collagen tubes were extruded using bovine collagen type I. The biodegradation rate was determined and compared for small diameter collagen tubes crosslinked with glutaraldehyde and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and Nhydroxysuccinimide (NHS) to evaluate physio-chemical properties. The samples were also evaluated for their surface area and porosity using mercury porosimeter. The noncrosslinked tubes almost completely degraded after 2 hours. The tubes crosslinked with EDC/NHS degraded slower than ...


Evaluation Of Effect Of Extrusion Process Variables On Mechanical Properties Of Extruded Collagen Tubes And Effect Of Post Extrusion Treatments, Mayank K. Patel May 2004

Evaluation Of Effect Of Extrusion Process Variables On Mechanical Properties Of Extruded Collagen Tubes And Effect Of Post Extrusion Treatments, Mayank K. Patel

Theses

This study evaluated the effect of extrusion process variable on mechanical properties of extruded collagen tubes made using a specialized extruder, made by ZOKO Corporation of Czechoslovakia. Three extrusion variables were considered; extrusion speed, linear draw rate and rotation speed. Using Taguchi L4 matrix, a design of experiment (DOE) was run. Two mechanical properties, wall thickness and estimated elastic modulus, were considered as response of this DOE. Data was analyzed statically to evaluate the effect of extrusion variables on both these properties. Result of this study showed that linear draw rate of the extrusion process has the highest influence ...


A Kinematic Analysis Of Hand Configurations In Static And Dynamic Fingerspelling, Gillian B. Sherry May 2004

A Kinematic Analysis Of Hand Configurations In Static And Dynamic Fingerspelling, Gillian B. Sherry

Theses

The focus of this study was the investigation of target handshapes in American Sign Language fingerspelling in order to determine whether there was a difference between static canonical structures and structures produced in the context of a movement sequence. This was achieved by measuring the joint angles of a signing hand with an 18-sensor CyberGlove® by Virtual Technologies, Inc.

A discriminant analysis was used to identify targets that occurred at points of minimum angular joint velocity. A multivariate analysis of variance with planned compansons was then applied to these dynamic data along with the static data to test the hypothesis ...


Particle Size Dependence On Immobilized Molecular Sensors : Assay Of Nucleic Acid Probes Attached To Paramagnetic Particles, Celin Sunny May 2004

Particle Size Dependence On Immobilized Molecular Sensors : Assay Of Nucleic Acid Probes Attached To Paramagnetic Particles, Celin Sunny

Theses

Nanotechnology is concerned with materials and systems whose structure and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena and processes due to their nano scale size.

The transition from micro scale to nano scale leads to a number of changes in physical properties, possibly including new physical principles, some of which may be yet to be discovered. One of the major factors in this is the increase in ratio of surface area to volume.

This thesis research uses the increase in ratio of surface area to volume property of going from macro to micro to nano ...


Mathematical Modeling And Simulation Of Human Motion Using 3-Dimensional, Multi-Segment Coupled Pendulum System : Derivation Of A Generalized Formula For Equations Of Motion, Loay Ahmed-Wasfe Al-Zube May 2004

Mathematical Modeling And Simulation Of Human Motion Using 3-Dimensional, Multi-Segment Coupled Pendulum System : Derivation Of A Generalized Formula For Equations Of Motion, Loay Ahmed-Wasfe Al-Zube

Theses

The use of mathematical models to investigate the dynamics of human movement relies on two approaches: forward dynamics and inverse dynamics. In this investigation a new modeling approach called the Boundary Method is outlined. This method addresses some of the disadvantages of both the forward and the inverse approach. The method yields as output both a set of potential movement solutions to a given motor task and the net muscular impulses required to produce those movements. The input to the boundary method is a finite and adjustable number of critical target body configurations. In each phase of the motion that ...


Application Of Bootstrap Resampling In Fmri, Arthika Bappal May 2004

Application Of Bootstrap Resampling In Fmri, Arthika Bappal

Theses

This thesis demonstrates the use of the bootstrap resampling technique considering temporal dependency in the fMRI data to determine the reliability and confidence interval of fMRI parameters. Traditionally, the test-retest method has been used to reliably detect active voxels in the fMRI image of the brain, which is based on repetitive experimentation. The main concern with the test-retest method is the reproducibility of data over these multiple repetitions. Fatigue, habituation, motion artifacts, and repositioning errors are few of the factors, which can affect the reproducibility of data.

The conventional bootstrap resampling technique is based on the assumption that the dataset ...


Effects Of Sleep Deprivation On Autonomic Nervous System, Jaeyeaon Cho May 2004

Effects Of Sleep Deprivation On Autonomic Nervous System, Jaeyeaon Cho

Theses

Sleep deprivation (SD) has been thought a potential factor to trigger cardiovascular events by increasing the sympathetic nervous system activity. The aim of the present study was to evaluate the relationship between sleep deprivation and the autonomic nervous system activity by means of heart rate variability (HRV) and blood pressure variability (BPV). All data were acquired in the sleep lab of Columbia University.

Data were acquired from the two groups, SD and control. Subjects in the SD group did not sleep for thirty-six hours but subjects in the control group slept at night as usual. There were five different data ...


An In Vitro Evaluation Of Tyrosine Derived Polyarylates And Polycarbonate As Polymeric Scaffold For Human Mesenchymal Stem Cells Osteogenic Differentiation, Manish Suresh Godbole May 2004

An In Vitro Evaluation Of Tyrosine Derived Polyarylates And Polycarbonate As Polymeric Scaffold For Human Mesenchymal Stem Cells Osteogenic Differentiation, Manish Suresh Godbole

Theses

Human mesenchymal stem cells (hMSCs) obtained from the adult bone marrow are multipotential cells that are capable of differentiating along several lineages. They are readily available and abundant source of cells in the field of tissue engineering. For their use in treating certain connective tissue defect or disorders, their success depends at minimum on the use of scaffolds that support differentiation. Therefore , this thesis details a study that systematically evaluated hMSC differentiation on materials that exhibit gradual range in surface properties as a first study for selecting materials as potential scaffolds. Polycarbonates and polyarylates have combinatorial libraries that exhibit a ...


Characterization Of Electrospun Dlplga Nanofibers For A Drug Delivery System For Intracranial Tumors And Avms, Kimberly A. Griswold May 2004

Characterization Of Electrospun Dlplga Nanofibers For A Drug Delivery System For Intracranial Tumors And Avms, Kimberly A. Griswold

Theses

Electrospinning processes apply electric fields to a polymer solution in order to produce strands of polymer in the nanoscale range. These polymer fibers are manipulated for their porosity, high surface area, fineness and uniformity. In order to create the ideal drug delivery system for intracranial arteriovenous malformations (AVMs) and tumors, D, L poly-(lactice-poly-glycolide) (DLPLGA) nanofibers were electrospun in a tetrahydrofuran (THF) solvent. Three different concentration ratios of DLPLGA, 85/15, 80/20, and 75/25 were analyzed to obtain the prime base for drug annexation. 1 ,3-bis (2-chloroethyl)- 1 -nitrosourea (BCNU) was then codissolved with the DLPLGA nanofibers to ...


Voice Onset Time Variation In Stop Consonant To Vowel Transitions, Abhishek Gunvant Parikh May 2004

Voice Onset Time Variation In Stop Consonant To Vowel Transitions, Abhishek Gunvant Parikh

Theses

Reduced duration, increased consistency, and improved intelligibility are goals of reducing the motor complexity of speech for individuals with cerebral palsy having dysarthria. In this study, measurement and analysis were made to compare an individual with spastic Cerebral Palsy (CP) having dysarthria to an individual with athetoid CP having dysarthria as well as to a non-dysarthric individual. Each participant's normal speech, whispering, and speech using an artificial larynx was evaluated, utilizing the source-filter theory methodology. The plausibility of dysarthric speech duration reduction by minimizing vocalization is tested by stop consonant "P,, to vowel transitions. The data suggest that speech ...


Fabrication Of Nanofiber Scaffolds By Electrospinning And It's Potential For Tissue Engineering, Shobana Shanmugasundaram May 2004

Fabrication Of Nanofiber Scaffolds By Electrospinning And It's Potential For Tissue Engineering, Shobana Shanmugasundaram

Theses

Electrospinning is a fabrication process that uses an electric field to control the deposition of polymer fibers on to a target substrate. This electrospinning strategy can be used to fabricate fibrous polymer mats composed of fiber diameters ranging from several microns down to tens of nanometers. This study assesses the potential of electrospinning, as an alternative scaffold fabrication technique for tissue engineering applications. In this study, electrospinning is adapted to produce tissue-engineering scaffolds of two different size ranges composed of non-woven poly-L-lactide (PLLA) nanofibers and as a first study, the potential use of these scaffolds as tissue engineering scaffolds was ...


Vegetative Recovery Of Military Vehicle Impacts At Fort Lewis, Wa, Katie Jean Simmons May 2004

Vegetative Recovery Of Military Vehicle Impacts At Fort Lewis, Wa, Katie Jean Simmons

Masters Theses

Vehicles driven off-road damage the soil and vegetation on the terrain, which can cause soil erosion and degradation of the landscape. This type of damage occurs on military installations due to training. Military training lands must be managed in an attempt to minimize the overall impacts of training on the terrain. The Army Training and Testing Area Carrying Capacity (ATTACC) is a model used by the U.S. Army to manage their training lands. Methods of determining the impacts produced by a vehicle and subsequent vegetative recovery have been used at Fort Lewis, WA for the Light Armored Vehicle (LAV ...


Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang Apr 2004

Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang

Doctoral Dissertations

The objective of this work is to design and fabricate an advanced silicon dioxide microcantilever sensor and to investigate chemical and biological sensing by microtechnology.

Microcantilever sensor technology has many advantages including fast response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. For all of these advantages, microcantilever chemical and biological sensors have drawn more and more attention.

So far, all other microcantilevers were designed and fabricated for AFM applications. We developed a novel SiO2 microcantilever especially for chemical and biological sensor applications ...