Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Retrospective Theses and Dissertations

Discipline
Keyword
Publication Year

Articles 1 - 30 of 98

Full-Text Articles in Biomedical Engineering and Bioengineering

Force Interaction Characterization Between Thrombin And Dna Aptamers, Janice Dionne Marquardt Jan 2008

Force Interaction Characterization Between Thrombin And Dna Aptamers, Janice Dionne Marquardt

Retrospective Theses and Dissertations

The first purpose of this study is to examine using AFM height measurements to detect changes in nucleic acid and protein interactions. This study used a thiolated adenine oligonucleotide (Poly A) and thymine DNA strand (Poly T) or 2 kDa poly(ethylene) glycol (PEG) as control, and the thrombin aptamer and thrombin for detection pair. The poly A and aptamer were printed using microcontact printing, then exposed to complementary species. There was a height change after binding to the target species, so it is feasible for height data to detect binding. The second purpose of this study is to use ...


Osteoarthritis: Clinical Evaluation And Cartilage Tissue Engineering, Wanda June Gordon-Evans Jan 2007

Osteoarthritis: Clinical Evaluation And Cartilage Tissue Engineering, Wanda June Gordon-Evans

Retrospective Theses and Dissertations

Osteoarthritis (OA) is the 2nd leading cause of long term disability in North America affecting 40 million Americans. The work presented in this manuscript addresses clinical outcome measures used to determine treatment effect and 2 in vitro studies using tissue engineering techniques to grow cartilage suitable for in vivo use. In the first study, radiographs of the stifle joint in dogs were scored for the severity of OA, and limb function was measured by force platform gait analysis. The 2 outcome measures were analyzed using regression methods. There was no correlation of the severity of radiographic OA and limb function ...


A Three-Dimensional Quantitative Biomechanical Analysis Of Left Handed Scanning, William Ray Brown Jan 2007

A Three-Dimensional Quantitative Biomechanical Analysis Of Left Handed Scanning, William Ray Brown

Retrospective Theses and Dissertations

No abstract provided.


The Surgical Implementation Of Osteoceramic Cement In Total Hip Arthroplasty: An In Vivo Study In Canines, Noah Wiese Jan 2007

The Surgical Implementation Of Osteoceramic Cement In Total Hip Arthroplasty: An In Vivo Study In Canines, Noah Wiese

Retrospective Theses and Dissertations

Osteoceramic cement (OC-cement) is a novel, ceramic-ceramic composite bone cement that has many properties that are superior to traditional polymethyl methacrylate (PMMA) cement. Prior to this research, the mechanical, chemical, biological, and setting properties of the cement had been studied, but in vivo testing was the necessary next step in developing it for use in joint replacement. In order to be able to perform surgery using OC-cement, an extensive amount of testing was done on properties that pertain to the handling and behavior of the cement in a surgical setting. This testing included investigations into cement rheology, working time variation ...


Engineering Polyanhydride Microspheres For The Stabilization And Controlled Release Of Proteins , Amy Sywassink Determan Jan 2006

Engineering Polyanhydride Microspheres For The Stabilization And Controlled Release Of Proteins , Amy Sywassink Determan

Retrospective Theses and Dissertations

This work investigates the use of polyanhydride microspheres as drug delivery carriers for therapeutic proteins. The polymers investigated are poly(sebacic anhydride) and opolymers of poly[1,6-bis(p-carboxyphenoxy)hexane] (poly(CPH)) and poly(SA), 20:80 (CPH:SA), 50:50 (CPH:SA), and 80:20 (CPH:SA). The model protein bovine serum albumin (BSA) was encapsulated in poly(SA), 20:80 (CPH:SA), 50:50 (CPH:SA), and 80:20 (CPH:SA) microspheres to determine the feasibility of using polyanhydrides as protein carriers. Poly(SA) and 20:80 (CPH:SA) were found to stabilize the encapsulated BSA and were ...


Resorption Rate Tunable Bioceramic: Si,Zn-Modified Tricalcium Phosphate , Xiang Wei Jan 2006

Resorption Rate Tunable Bioceramic: Si,Zn-Modified Tricalcium Phosphate , Xiang Wei

Retrospective Theses and Dissertations

An ideal bone implant material would support the activity of osteoblasts in the development of new bone, while simultaneously being resorbed by osteoblasts as part of the lifelong orderly process of bone remodeling. Silicon and Zinc modified tricalcium phosphate (Si,Zn-TCP), a biphasic material, was synthesized as a candidate for resorbable temporal bone implant having a controlled solubility and pharmaceutical effect to promote bone formation. From XRD and ICP analyses, it was shown that up to 10% Si and Zn were incorporated in tricalcium phosphate (TCP) without formation of a secondary phase. Changes in lattice parameters and unit volume of ...


Analysis And Control Theory Of Some Cochlear Models , Isaac Chepkwony Jan 2006

Analysis And Control Theory Of Some Cochlear Models , Isaac Chepkwony

Retrospective Theses and Dissertations

The standard 2-dimensional cochlear model consists of a 1-dimensional elastic structure, modeling the basilar membrane, surrounded by an incompressible 2-dimensional fluid within a 2-dimensional cochlear cavity. The dynamics are typically driven by a pressure differential across the basilar membrane transmitted through the round and oval windows (a portion of the boundary of the cochlear). First we describe a model in which the basilar membrane is modeled as an infinite array of oscillators and the fluid is described by Laplace's equation. In this setting, we show that the coupled system is approximately controllable with control acting on an arbitrary open ...


Recovery And Purification Of Recombinant Protein From Transgenic Corn By Aqueous Two-Phase Partitioning , Zhengrong Gu Jan 2006

Recovery And Purification Of Recombinant Protein From Transgenic Corn By Aqueous Two-Phase Partitioning , Zhengrong Gu

Retrospective Theses and Dissertations

Aqueous two-phase (ATP) partitioning was paired in a variety of ways to use of transgenic corn for protein expression. Systems were developed to selectively partition corn proteins from classes of potential recombinant proteins as well as the specific case of dog gastric lipase. More fundamentally, ATP partitioning was used to expand 2D gel electrophoretic characterization of protein size and pI to the third dimension of hydrophobicity with the usefulness of the method illustrated for corn extracts;ATP partitioning in polyethylene glycol (PEG)-salt systems separates proteins primarily according to their surface hydrophobicity differences. The average hydrophobicity of pH 7 extracts ...


Directed Growth And Selective Differentiation Of Neural Progenitor Cells Using A Synergistic Combination Of Topographical And Soluble Cues , Jennifer Behr Recknor Jan 2006

Directed Growth And Selective Differentiation Of Neural Progenitor Cells Using A Synergistic Combination Of Topographical And Soluble Cues , Jennifer Behr Recknor

Retrospective Theses and Dissertations

The purpose of this study is to develop strategies to facilitate nerve regeneration using a synergistic combination of guidance cues. We are investigating the cellular mechanisms of development using adult rat hippocampal progenitor cells (AHPCs) and have demonstrated that manipulating a combination of physical, chemical and biological cues can lead to oriented astrocyte and neural progenitor cell outgrowth and can influence progenitor cell differentiation. To provide physical guidance, micropatterned polystyrene (PS) substrates were fabricated and chemically modified with laminin. Astrocytes or AHPCs cultured on these substrates align along the grooves of the patterned surface extending highly elongated processes. To further ...


Investigation Of The Performance Of Articular Cartilage And Synthetic Biomaterials In Multi-Directional Sliding Motion As In Orthopedic Implants , Christian John Schwartz Jan 2006

Investigation Of The Performance Of Articular Cartilage And Synthetic Biomaterials In Multi-Directional Sliding Motion As In Orthopedic Implants , Christian John Schwartz

Retrospective Theses and Dissertations

The performance of several synthetic biomaterials and bovine articular cartilage were investigated in terms of their suitability for use as articulating surfaces in artificial joints. The Dual-Axis Wear Simulator (DAWS), a wear testing machine that simulates conditions in a synovial joint, was designed and fabricated to enable investigators to measure the wear of such materials in multi-directional sliding while immersed in a bovine serum lubricant solution. This machine was used initially to determine the wear mechanisms and wear amounts of ultra-high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), and the compliant elastomer Pellethane(TM) 2363-80A. It was found that ...


Integral Transport Based Deterministic Brachytherapy Dose Calculations , Chuanyu Zhou Jan 2004

Integral Transport Based Deterministic Brachytherapy Dose Calculations , Chuanyu Zhou

Retrospective Theses and Dissertations

Brachytherapy usually refers to a category of procedures where radiation sources are implanted into the tumor or into its close vicinity to deliver high radiation doses into the tumor for a therapy. A feedback about the dose rate distribution during the surgery is desired to guarantee the dose coverage and the success of a treatment. Calculation speed is crucial in this attempt and traditional Monte Carlo methods are not suitable for this purpose.;We developed a deterministic algorithm for computing three dimensional brachytherapy dose distributions. The deterministic algorithm has been based on the integral transport equation. The integral transport equation ...


Engineering Bioerodible Polymers With Tailored Micro/Nanostructure For Vaccine Delivery , Matthew J. Kipper Jan 2004

Engineering Bioerodible Polymers With Tailored Micro/Nanostructure For Vaccine Delivery , Matthew J. Kipper

Retrospective Theses and Dissertations

This work describes the investigation of bioerodible polyanhydrides as controlled drug delivery vehicles. The polymers studied are based on the 1,6-bis(p-carboxyphenoxy)hexane (CPH) and sebacic acid (SA) monomers. These two materials erode at vastly different rates and can be combined in random copolymers or blends to achieve tailored erosion kinetics. The hydrophobic nature of these materials offers the potential to stabilize proteins, and their mutual incompatibility and semicrystallinity provide an interesting phase behavior, which can be exploited to aid in tailoring the release kinetics. Theoretical and experimental description of the microstructure of polyanhydride copolymers reveals the details of ...


Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson Jan 2002

Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson

Retrospective Theses and Dissertations

The aim of this work was to obtain a fundamental understanding of drug release mechanisms from polymers that undergo thermoreversible gelation and to synthesize new polymers based on these that exhibit both pH and temperature sensitivity. Novel block and random copolymers with cationic character have been developed for drug delivery and gene therapy applications. The development of these materials began with a study of the mechanism of drug release from poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) block copolymers. This study revealed the release rates of drugs from water-soluble hydrogels composed of the PEO-PPO-PEO block copolymer PluronicRTM F127 ...


Calcium Phosphate Compatible Bone Cement: Characterization, Bonding Properties And Tissue Response , Maria Lynn Roemhildt Jan 2002

Calcium Phosphate Compatible Bone Cement: Characterization, Bonding Properties And Tissue Response , Maria Lynn Roemhildt

Retrospective Theses and Dissertations

A novel, inorganic, bone cement, containing calcium phosphate, developed for implant fixation was evaluated. Setting properties were determined over a range of temperatures. The flow of the cement was greatly increased by application of vibration. Changes in the cement during hydration and aging were evaluated. Compressive strength of the cement over time was studied under simulated physiological conditions from 1 hour to 1 year after setting. After 1 day, this cement had equivalent compressive strength to commercially used PMMA cement. The strength was found to increase over 1 month and high strength was maintained up to 1 year.;The shear ...


Total Elbow Replacement In The Dog: Development And Evaluation , Michael Gerard Conzemius Jan 2000

Total Elbow Replacement In The Dog: Development And Evaluation , Michael Gerard Conzemius

Retrospective Theses and Dissertations

Elbow osteoarthritis (OA) is the most common cause of forelimb lameness in the dog. The goal of nonsurgical and/or surgical management of the diseases that cause elbow OA is to slow the progression OA in the joint and reduce lameness in the patient. Nonsurgical and surgical management of these conditions frequently leads to unsatisfactory results. Current treatment alternatives for dogs with moderate to severe elbow OA include nonsurgical management, removing loose bodies and osteophytes from the joint, and arthrodesis. Similarly, these treatments frequently lead to a poor outcome. Improvements in implant design and surgical techniques have made total elbow ...


Micro And Nanopatterned Biodegradable Polymer Films For Peripheral Nerve Regeneration , Cheryl Ann Miller Jan 2000

Micro And Nanopatterned Biodegradable Polymer Films For Peripheral Nerve Regeneration , Cheryl Ann Miller

Retrospective Theses and Dissertations

Annually over 200,000 surgeries are attempted to repair peripheral nerve damage.1 Without these surgeries, peripheral nerve transections have little hope of reinnervating the effector organ and becoming fully functional if the nerve endings are separated by a centimeter or more. Currently, transections are repaired with nerve autografts removed from one part of the body to repair the injured site. Autografting causes deinnervation of the donor site and tissue availability is limited.;An alternative nerve repair method to grafting is an entubulization method where a conduit is used to connect the nerve endings. The conduit allows for chemical communications ...


Utility Of Spectrum And Wavelet Analysis Of Heart Rate Variability As A Tool To Assess Orthostatic Intolerance , Kichang Lee Jan 2000

Utility Of Spectrum And Wavelet Analysis Of Heart Rate Variability As A Tool To Assess Orthostatic Intolerance , Kichang Lee

Retrospective Theses and Dissertations

Three studies were performed to test the hypotheses: (1) lower body negative pressure (LBNP) tolerance, autonomic, and cardiovascular responses to the LBNP are reproducible, (2) women have a lower LBNP tolerance and less ability to maintain homeostasis in cardiovascular system against orthostatic stress, and (3) wavelet analysis technique is a unique tool to study the autonomic nervous activities during LBNP test. College-age men and women underwent graded LBNP to either presyncope or -100 mmHg in increments of 10 mmHg negative pressure every 6 minutes;The LBNP tolerance were highly reproducible (cumulative stress index: 1698 +/- 171 vs 1938 +/- 139, trial 1 ...


Algorithms For Enhancing Pattern Separability, Feature Selection And Incremental Learning With Applications To Gas Sensing Electronic Nose Systems , Robi Polikar Jan 2000

Algorithms For Enhancing Pattern Separability, Feature Selection And Incremental Learning With Applications To Gas Sensing Electronic Nose Systems , Robi Polikar

Retrospective Theses and Dissertations

Three major issues in pattern recognition and data analysis have been addressed in this study and applied to the problem of identification of volatile organic compounds (VOC) for gas sensing applications. Various approaches have been proposed and discussed. These approaches are not only applicable to the VOC identification, but also to a variety of pattern recognition and data analysis problems. In particular, (1) enhancing pattern separability for challenging classification problems, (2) optimum feature selection problem, and (3) incremental learning for neural networks have been investigated;Three different approaches are proposed for enhancing pattern separability for classification of closely spaced, or ...


Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski Jan 1999

Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski

Retrospective Theses and Dissertations

Nerve injuries complicate successful rehabilitation more than any other form of trauma because of loss of protective sensibility and tactile discrimination, denervation atrophy of muscles, and pain syndromes. While achieving full function and organ reinnervation after peripheral nerve injury is a challenge, a promising method of improving the rate and success of regeneration is the bioartificial nerve graft (BNG). The BNG developed in the laboratory consists of a porous bioresorbable tube containing cultured Schwann cells that help to direct and support nerve regeneration when used to bridge the gap between the ends of the severed nerve;To aid in the ...


A Three-Dimensional, Dynamic Model Of The Human Body For Lifting Motions , Jason Clay Gillette Jan 1999

A Three-Dimensional, Dynamic Model Of The Human Body For Lifting Motions , Jason Clay Gillette

Retrospective Theses and Dissertations

Lower back pain is prevalent in society and manual lifting has been linked as one potential cause of these types of injuries. Therefore, the 3dLift biomechanical model was developed in this research with the goal of quantitatively analyzing lifting motions. The model divided the body into fifteen segments that were connected by fourteen anatomical joints. During experimental trials, a volunteer subject lifted an object using four different lifting combinations: symmetric leglifts, asymmetric leglifts, symmetric backlifts, and asymmetric backlifts. In order to individualize the 3dLift model, anthropometric parameters were estimated using measurements taken on the subject. During the lifting trials, the ...


Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey Jan 1998

Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey

Retrospective Theses and Dissertations

A model of the human body which integrates the variables involved in temperature regulation and blood gas transport within the cardiovascular and respiratory systems is presented in this dissertation. It expands upon previous work developed by the author to model the competition between skin and muscles when both require increased blood flows during exercise and/or heat stress. First, a detailed study of the control relations used to predict skin blood flow was undertaken. Four other control relations employed in the model were also examined and modified as indicated by empirical results found in literature;Several important cases were then ...


Development Of A Multiple-Lumen Nerve Cuff Utilizing Growth Stimulant Patterns For Controlled Regeneration , Yueh-Sheng Chen Jan 1998

Development Of A Multiple-Lumen Nerve Cuff Utilizing Growth Stimulant Patterns For Controlled Regeneration , Yueh-Sheng Chen

Retrospective Theses and Dissertations

Silicone rubber multiple-lumen nerve cuffs were used to compare the effectiveness of two varieties of nerve growth stimulants (collagen and a mixture of collagen, fibronectin, and laminin) at the same time for regenerating cables across the same gap. The right sciatic nerve was transected in adult Sprague-Dawley rats. The proximal and distal stumps were inserted each into an end of the single lumen portion of a multiple-lumen cuff in which different chemical fillings were used in 6 tubes of the multiple lumen portion of the cuff. The filling pattern alternated with collagen gel or with a gel mixture of collagen ...


The Effects Of Physiological Levels Of Intermittent Pressure On The Development Of Articular Cartilage In Vitro , Scott Edward Carver Jan 1998

The Effects Of Physiological Levels Of Intermittent Pressure On The Development Of Articular Cartilage In Vitro , Scott Edward Carver

Retrospective Theses and Dissertations

A semi-continuous perfusion system has been designed and constructed to deliver physiological levels of hydrostatic pressure to regenerating cell/polymer constructs of articular cartilage over the long term (weeks to months). Prior to being transferred to the pressurized system, equine articular chondrocytes were dynamically seeded onto nonwoven meshes of polyglycolic acid which provide the cells with a three-dimensional growth environment similar to that found in vivo. When applied in an intermittent manner, physiological pressurization at 500 psi was found to stimulate articular chondrocytes to produce regenerated constructs with greater concentrations of sulfated glycosaminoglycan compared to control (unpressurized) constructs, while the ...


A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee Jan 1997

A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee

Retrospective Theses and Dissertations

The object of this dissertation is to quantitatively describe the regulation of some of the exchange processes within the human body. Conceptually this dissertation is divided into two sections. In the first section a macroscopic view was adopted to describe the overall regulation of the cardiovascular and respiratory systems. These overall system models were used as heuristic tools to gain an understanding of physiological behavior in micro-gravity. In the second section, a microscopic view was used to estimate the role played by the surfactant system of the lung in regulating the transfer of fluid across the pulmonary-capillary wall;The basis ...


Interaction Of Acoustic Beam With Elastic Structures , Han Zhang Jan 1997

Interaction Of Acoustic Beam With Elastic Structures , Han Zhang

Retrospective Theses and Dissertations

This thesis describes experiments and calculations performed on the interaction of acoustic beams in water and air with planar and cylindrical elastic structures. Ultrasonic reflection measurements have been used to elucidate the phenomena of guided wave generation and reradiation by selecting beam incidence at, or near, phase-matching conditions. Under these circumstances reasonant mode conversion of accoustic wave to guided wave mode energy can occur. This interaction has been studied in rubber-coated steel, aluminum, plexiglas, and graphite-epoxy composite. The acoustic coupling media used in these experiments has been either water or air;Some theoretical modeling has also been undertaken to explain ...


Calcium Phosphate Ceramic Composites Used For Orthopedic Implant Applications , Curtis Eugene Olson Jan 1996

Calcium Phosphate Ceramic Composites Used For Orthopedic Implant Applications , Curtis Eugene Olson

Retrospective Theses and Dissertations

The objective of the first of two research projects was to make a new composite material that would have both bone bonding capabilities and appropriate mechanical properties for use in orthopedic applications. Implant-bone responses were compared using transcortical implants designed from osteoceramic fired in air, osteoceramic fired in hydrogen, 316L stainless steel mixed with aggregates of osteoceramic, 316L stainless steel, and ultra high molecular weight polyethylene mixed with aggregates of osteoceramic. The osteoceramic material, developed at Iowa State University, was a biologically active composite consisting of tricalcium phosphate and magnesium aluminate spinel;Ten of each of these implants were placed ...


Computer Simulation Of Coronary Blood Flow , Brian Christopher Frake Jan 1995

Computer Simulation Of Coronary Blood Flow , Brian Christopher Frake

Retrospective Theses and Dissertations

A computer model to simulate coronary fluid dynamics has been developed which can give some insight into the role of hemodynamics in health and disease. Although this study focuses mainly on coronary blood flow, the complete model consists of all major branches of the systemic circulation as well as the left epicardial coronary circulation;The flow equations are obtained by integrating the one-dimensional continuity and momentum equations over the cross-section of the artery to give a relationship between the primary variables of interest, the pressure and flowrate. An arctangent model was used as a constitutive equation to describe the pressure-area ...


The Production Of Textile Fibers From Soy Proteins , Hsin-Chi Huang Jan 1994

The Production Of Textile Fibers From Soy Proteins , Hsin-Chi Huang

Retrospective Theses and Dissertations

The use of soy protein presently is limited mostly to animal feeds, but the markets for soy protein could be expanded by industrial applications. In these studies, soy fibers were produced from soy protein isolate using both wet spinning and extrusion methods. The wet spinning process consisted of forcing an aged alkaline protein solution through a spinnerette having 368-[mu] openings into an acid coagulating bath. The extrusion process employed a twin screw extruder to force a protein-water mixture with "dough-like" consistency through a die also with 368-[mu] openings. The physical properties of the fibers were measured at 11 ...


Modeling Joint Kinetics In The Tkatchev Release Move , Martha Nichols-Ketchum Jan 1994

Modeling Joint Kinetics In The Tkatchev Release Move , Martha Nichols-Ketchum

Retrospective Theses and Dissertations

This study developed a three-dimensional computer simulation model of the Tkatchev release move on the men's horizontal bar. The model used the Hanavan human body model and the inverse dynamics approach to predict resultant forces and torques at the joints during performance. The model was used to determine aspects of the performance that contribute to the risk of injury and to determine strength and flexibility requirements for the skill;This study was done in two parts. In Part 1, kinetic parameters were calculated from actual performances of Tkatchevs. Two college-level male gymnasts each performed 9-10 Tkatchevs during a single ...


Water And Electrolyte Regulation During Space Flight And Exercise , Susan Elizabeth Doty Jan 1994

Water And Electrolyte Regulation During Space Flight And Exercise , Susan Elizabeth Doty

Retrospective Theses and Dissertations

When one is exposed to microgravity, fluid which is normally pooled in the lower extremities is redistributed headward and weight bearing bones begin to demineralize due to reduced mechanical stresses. The kidney, which is the primary regulator of body fluid volume and composition, responds to the fluid shift and bone demineralization by increasing the urinary output of water, sodium, and calcium. This research involves developing a mathematical description of how water and electrolytes are internally redistributed and exchanged with the environment during space flight. Various levels of activity are also considered, since it is believed that exercise can prevent some ...