Engineering Commons^™

Role Of Mitochondrial Electron Transport Complex I In Coenzyme Q1 Reduction By Intact Pulmonary Arterial Endothelial Cells And The Effect Of Hyperoxia, Marilyn P. Merker, Said H. Audi, Brian J. Lindemer, Gary S. Krenz, Robert D. Bongard

Biomedical Engineering Faculty Research and Publications

The objective was to determine the impact of intact normoxic and hyperoxia-exposed (95% O(2) for 48 h) bovine pulmonary arterial endothelial cells in culture on the redox status of the coenzyme Q(10) homolog coenzyme Q(1) (CoQ(1)). When CoQ(1) (50 microM) was incubated with the cells for 30 min, its concentration in the medium decreased over time, reaching a lower level for normoxic than hyperoxia-exposed cells. The decreases in CoQ(1) concentration were associated with generation of CoQ(1) hydroquinone (CoQ(1)H(2)), wherein 3.4 times more CoQ(1)H(2) was produced in the normoxic than hyperoxia-exposed cell medium (8.2 +/- 0.3 and 2.4 +/- 0.4 microM, …

Novel Model Of Cerebrospinal Fluid Dynamics Based On Hemodynamically Driven Cyclic Brain Compliance Variation, Bruno A. Mantilla

Dissertations

This study provides a novel explanation for the CerebrQ-Spinal Fluid (CSF) flow pattern observed in phase contrast cine-MRJ studies. CSF dynamics has been traditionally explained as a bulk flow from the site of production to the site of absorption. Studies done with phase contrast cine-MRI show a more complex CSF movement, that is not explainable by the bulk flow paradigm. This study describes a mechanism explaining how the energy delivered by the heart in each cycle is responsible not only for the blood flow, but also for the CSF circulation. This mechanism is based on a cyclic variation of brain …

Theoretical Framework For Predicting Joint Reaction And Ground Reaction Forces In A Dynamic Pendulum Tree Model Of Human Motion, Peyman Rajai

Theses

Lagrangian dynamics and the method of superfluous coordinates are applied to find ground and joint reaction forces on the human body modeled as a general branched 2-D pendulum tree system with arbitrary segments and arbitrarily distributed point masses. A theoretical framework is established for predicting these constraint forces during human motion and consequently their effects on dynamics, dynamic stability, energy efficiency and the potential of these forces to produce joint injury and/or pain. Applications to human walking are initiated. During idealized phases where there is only single point contact of the stance leg with the ground such as just after …

An In Vitro Evaluation Of Dbm As A Tissue Engineered Scaffold, Stephanie Arnold

All Theses

Over 500,000 bone graft procedures are performed each year in the United States. Bone grafting involves a surgical procedure to replace missing bone. Problems can arise with donor and defect sites during and after surgery, sometimes resulting in poor clinical results. The development and optimization of bone graft substitutes via a tissue engineering approach could markedly improve bone graft surgical outcome. Demineralized bone matrix (DBM), a bone graft material, is currently used in a clinical setting but has variable success rates.
The primary objective of the research presented in this thesis was to assess the cellular activity of D1 mouse …

Glycosaminoglycan Stabilization Reduces Tissue Buckling In Bioprosthetic Heart Valves, Sagar Shah

All Theses

Currently, bioprosthetic heart valves are crosslinked with glutaraldehyde to prevent tissue degradation and to reduce tissue antigenicity. Glutaraldehyde forms stable crosslinks with collagen via a Schiff base reaction of the aldehyde with an amine group of the hydroxylysine/lysine in collagen. However, within a decade of implantation, 20-30% of these bioprostheses will become dysfunctional and over 50% will fail due to degeneration within 12-15 years post-operatively.
Gylcosaminoglycans, a major constituent of valvular tissue, play an important role in maintaining a hydrated environment necessary for absorbing compressive loads, modulating shear stresses, and resisting tissue buckling. One of the disadvantages of glutaraldehyde crosslinking …

In Situ Photopolymerized Hydrogels For Enhancing Protein Delivery, Chien-Chi Lin

All Dissertations

In recent years, there has been immense interest in the utilization of photopolymerized hydrogels as carriers for controlled protein delivery and cell scaffolds for tissue engineering applications. Although poly(ethylene glycol) (PEG)-based hydrogels formed from mild photopolymerization methods have been suggested as biocompatible matrices that allow for safely encapsulating biomolecules including proteins, peptides, DNA, and cells, the adverse effects of photopolymerization reactions on the encapsulated proteins have largely been overlooked. In addition, conventional hydrophilic hydrogels fail to effectively control protein delivery rates due to their high permeability. These two problems are critical since the delivery of protein therapeutics from hydrogel matrices …

Differentiation Modulation Of Adult Stem Cells In An Adipose System, Aditya Chaubey

All Dissertations

The need for soft tissue reconstruction or augmentation has increased continuously over the years. This need is compounded by patients suffering from post-traumatic repair and congenital soft-tissue deformities. All the current options available to treat the soft tissue deformities have inherent difficulties associated with them. Hence, more research is needed to come up with a better solution to this problem which is only going to increase in magnitude. Tissue engineering is a relatively new technique which has the potential to deliver a cell-based device which can overcome the problems associated with traditional therapies. However, before it becomes clinically viable we …

Non-Boltzamann Sampling For The Accurate Calculation Of Peptide-Surface Adsorption Free Energy, Feng Wang

All Dissertations

%Abstract
The objectives of this project are 1) the setup and refinement of peptide-SAM surface model systems with explicit water using CHARMM and 2) the development of up-to-date simulation protocols for the accurate calculation of adsorption free energy by incorporating the recent development of non-Boltzmann sampling methods in molecular dynamics and applying it for the calculation of adsorption free energy of short peptides onto well-characterized self-assembled monolayers, which is important for understanding protein/surface interactions.
A software package called the Simulation Template Engine for Peptides at Surfaces (STEPS) was developed for the fulfillment of the first objective. It facilitates the automatic …

Activation Of Systemic Adhesion Molecules And C Reactive Protein In Response To Biomaterial Particle Induced Cytokine Production, Robin Graham

All Dissertations

Chronic inflammation has been identified as a major contributor to many diseases including, atherosclerosis, osteoporosis, dementia, Alzheimer's disease and type 2 diabetes, to name a few. Many of the same markers of inflammation found in the diseases listed above, including IL-1, IL-6, TNF-α, NF-B and adhesion molecules, have also been found in wear debris induced osteolysis. While the local response to biomaterial wear debris has been characterized quite extensively, very little is known about the systemic effect of biomaterial wear debris on the inflammatory system. The objectives of this study were to evaluate the in vitro and in vivo inflammatory …

Detection Of Aortic Calcification During Vertebral Fracture Assessment (Vfa) Compared To Digital Radiography, John T. Schousboe, Kevin E. Wilson, Thomas N. Hangartner

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Background: Cardiovascular disease is the most common cause of mortality among post-menopausal women. Our objective was to determine whether or not lateral spine images obtained on a bone densitometer to detect prevalent vertebral fracture can also accurately detect radiographic abdominal aortic calcification (AAC), an important risk factor for cardiovascular disease independent of clinical risk factors.

Methodology/Principal Findings: One hundred seventy four postmenopausal women had bone densitometry, lateral spine densitometry imaging (called vertebral fracture assessment, or VFA), and lateral spine digital radiographs. Radiographs and VFA images were scored for AAC using a previously validated 24 point scale and a simplified, …

Large Array Emg Monitoring Of Lumbar Region Muscle Action In Discogenic Low Back Pain, Jazzmyne Ann Richardson Buckels

Bioengineering Theses - Archive

This project explored the use of large array surface electromyography (LASE) as a technique for assessing the patterns of muscular activity under standardized loading conditions in patients with lumbar disc related pain and healthy subjects. Specifically, the project evaluated quantitative parameters of visually observed patterns of muscle action proposed to clinically discriminate between groups. If such correlates exist, then, this work may lead to technology assessment for sensitivity and specificity as a diagnostic procedure. Solutions to the issues for determining the effects of low back pain (LBP) on force and moment generation in the spine as well as its effect …

A Functional Analysis Of The Mechanically And Metabolically Sensitive Components Of The Skeletal Muscle Exercise Pressor Reflex In Hypertension, Anna Katherine Leal

Bioengineering Theses - Archive

Background - In hypertension, physical activity creates a risk for adverse cardiac events by causing exaggerated increases in mean arterial pressure (MAP) and heart rate (HR). One physiological mechanism responsible for this cardiovascular hyperactivity is the exercise pressor reflex (EPR). The EPR is a neural pathway originating in skeletal muscle that contributes to cardiovascular regulation during exercise. The EPR is composed of two afferent arms: one is comprised of mostly mechanically sensitive, group III afferent fibers that respond to muscle stretch and pressure, and the other is predominantly metabolically sensitive, group IV afferent fibers that respond to the chemical milieu …

Development Of A Broadband Multi-Channel Nirs System For Quantifying Absolute Concentrations Of Hemoglobin Derivatives And Reduced Scattering Coefficients, Dheerendra Kashyap

Bioengineering Dissertations - Archive

Near infrared spectroscopy (NIRS) has been widely applied to investigate hemoglobin oxygenations of muscles, brain and breast tumors. Steady state reflectance techniques developed previously have been restricted to determination of relative concentrations. To overcome these limitations, this dissertation describes the development, validation and applications of broadband, steady-state, optical spectroscopic systems and algorithms to quantify absolute concentrations of hemoglobin derivatives and reduced light scattering coefficients using (1) thin optical probes with small (100 μm - 1 mm) source-detector separations and (2) a large separation (< 4 cm) probe.. A recently developed mathematical model by Zonios and Dimou for reflectance at small source-detector separations was used to develop techniques to quantify chromophore concentrations and light scattering coefficients (Chap. 2). Blood-intralipid phantom models were used to determine empirical coefficients to model reflectance spectra. This technique was further applied to quantify hemodynamic changes during formalin- induced pain behaviors in rats (Chap. 3). To overcome limitations in penetration depth and investigated tissue volume, another approach to quantify concentrations of chromophores in tissues at large source-detector separations was also developed. This novel approach uses the process of second differential spectroscopy to quantify concentrations of deoxygenated hemoglobin with respect to the tissue water content. Based on such quantification, an adaptation of the ant colony optimization algorithm was utilized to quantify absolute concentrations of other constituent tissue chromophores. The developed techniques were validated with the reflectance measurements from blood-intralipid phantoms and further applied to monitoring of ex vivo human prostate lesions and of rat brain tumor growth in vivo (Chap. 4). In the second stage of my doctoral development, a multi-channel, broadband, steady-state, NIRS imaging system was developed to determine spatial distributions of hemoglobin concentrations and reduced light scattering coefficients. The imager was calibrated with laboratory phantoms to eliminate deterministic instrumentation bias of CCD-spectrometers, optical fibers, and multiplexer channels. Calibration procedures also include determinations of the source strength and boundary coefficients in order to obtain accurate image reconstructions. A multi-wavelength, spectrally constrained reconstruction algorithm was developed to obtain tomographic maps of hemoglobin derivative concentrations and reduced scattering coefficients, using laboratory tissue phantoms. The developed imaging system and reconstruction algorithms were validated with both static and dynamic multi-tube phantoms.

Resolution And Localization In Single Molecule Microscopy, Sripad Ram

Bioengineering Dissertations - Archive

Rayleigh's criterion is extensively used in optical microscopy to determine the resolution of microscopes. Despite its widespread use, it is well known that this criterion is based on heuristic notions and can be surpassed in a regular optical microscope. The inadequacy of Rayleigh's criterion has necessitated a reassessment of the resolution limits of optical microscopes. The thesis proposes a new resolution criterion that overcomes the limitations of Rayleigh's criterion. The new result predicts that there is no resolution limit, but that the resolvability depends on the number of detected photons. Analytical tools are introduced to estimate the distance from microscopy …

Spatial Resolution And Biliary Tissue Classification Properties Of A Near Infrared Light Imaging Probe, Praveen Kumar Gulaka

Bioengineering Theses - Archive

Approximately 500,000 Gallbladder Surgeries or Laparoscopic Cholecystectomies are performed annually to remove the Gallbladder. This surgery becomes necessary due to formation of gall stones. As biliary tract tissues are embedded in fat, differentiating them from neighboring tissues and blood vessels is critical in helping surgeons during laparoscopic cholecystectomy to avoid post-surgical complications. Optical spectroscopy (in both visible and near infrared regions) is investigated as a possible technique to identify biliary tract tissues and blood vessels. Such reflectance measurements provide information of effective attenuation, which is an index of optical properties of the tissue.Specifically, optical reflectance measurements were made on biliary …

Characterization Of A Hyperspectral Imager: A Diagnostic Tool For Monitoring Retinal Diseases, Nirad Zinzuwadia

Bioengineering Theses - Archive

We developed a novel hyperspectral slit lamp ophthalmoscope for visualizing vascular changes for clinical monitoring of retinal diseases, for example, diabetic retinopathy. The device consists of a visible charge couple device, CCD, and liquid crystal tunable filter, LCTF, coupled to the standard clinical slit lamp ophthalmoscope. The LCTF is used as a spectral light source illuminating the retina with different wavelengths of light that are recorded by the CCD and stored as a series of wavelength dependent images of the retina. Chemometric analysis produces a gray scale encoded image for the percentage of oxyhemoglobin at each pixel within the field …

Detection Of Positive Cancer Margins Intra-Operatively During Nephrectomy And Prostatectomy Using Optical Reflectance Spectroscopy, Disha Laxman Peswani

Bioengineering Theses - Archive

In recent years optical spectroscopies have become the basis for popular research activity directed towards the development of novel, noninvasive technologies for tissue diagnostics. The motivation for my research was to eliminate the need for surgical removal of tissue samples for biopsy and histology. With the help of an optical probe placed on or near the surface of the tissue, Near Infrared (NIR) spectroscopy can provide diagnostic signatures, non-invasively and in real time. While the ultimate goal vi is the elimination of the need to remove tissue samples, this technology can also be used to provide additional guidance during laparoscopic …

Foreign Body Reactions To Neural Implants In The Brain, Parisa Lotfi

Bioengineering Theses - Archive

Neural implants have been used and studied for many decades. They are applied to record neural signals or to locally deliver drugs. Unfortunately, foreign body reaction and accompanied glial scar formation often lead to implant failure. The lack of knowledge about the molecular mechanism governing foreign body reactions in the brain significantly hinders the development of brain implantable devices with improved safety and biocompatibility. To study the immune responses to brain implants, a novel animal model has been developed and used for the following investigation. Our studies have established cell recruitment time courses of astrocytes, microglial cells, lymphocytes, monocytes and …

Functionalized Nanoparticles For The Selective Killing Of Cancer Cells, Paul Todd Thevenot

Bioengineering Theses - Archive

The use of nanoparticles for cancer imaging and drug delivery has produced some success in improving the efficacy and safety of cancer chemotherapy. It is generally believed that the efficiency of nanoparticle-based cancer therapy would be greatly improved if such particles could be designed to directly interact with and eradicate tumor. Many recent studies have revealed that surface functionality plays an important role in particle:cell interactions. Using titanium dioxide (TiO2) nanoparticles (21 nm diameter) as test subjects, nanoparticles with different functional groups, hydroxyl (-OH), amine (-NH2), and carboxyl (-COOH) were produced and used in this investigation. An in vitro cell …

Cytotoxic Evaluation And Factorial Analysis Of 3d Photopolymerizable Thermoresponsive Composite Nanoparticle Hydrogels For Controlled Drug Delivery In Restenosis And Wound Healing, Abhimanyu Rajaram Sabnis

Bioengineering Theses - Archive

To develop a smart drug delivery system for restenosis and wound healing applications, we investigated photopolymerizable composite nanoparticle hydrogels which can release the drug in a temperature-responsive manner. Our novel system consisting of thermoresponsive poly(N-isopropylacrylamide-co-acrylamide) (PNIPA-AAm) nanoparticles and poly(ethylene glycol) diacrylate (PEGDA) as photo cross-linker can be formed in situ in presence of ultraviolet (UV) light and Irgacure 2959 photoinitiator (PI). The main aims of this project were to investigate the system cytotoxicity and optimize drug release characteristics by performing biocompatibility and factorial analysis studies, respectively. We evaluated the cell survival of human vascular smooth muscle cells and NIH/3T3 fibroblasts …

Investigation Of Brain Activities Using Two State-Of-The-Art Diffuse Optical Imagers, Suresh Prajapati

Bioengineering Theses - Archive

Near-Infrared Spectroscopy (NIRS) and diffuse optical imaging (DOI) are increasingly used to detect hemodynamic changes in the cerebral cortex induced by brain activity. The new commercially available DOI systems CW5 and DYNOT have large number of sources and detectors; by arranging them in specific patterns, one can cover most of the adult head. This study is a preliminary step in understanding CW5 and DYNOT and exploring their capabilities for various purposes. My work is divided in to three major parts. The first goal of this study was to study changes in hemodynamic response of brain during Breath holding, using both …

Gas Permeation Through Nanoporous Polycarbonate Track- Etched Membranes: Pulsed Plasma Polymerization Of Thin Coatings To Modulate Gas Permeability, Christopher Lewis Chapman

Bioengineering Theses - Archive

Polycarbonate track-etched membranes (PCTE) of 50nm and 100nm pore size, precoated with Poly Vinyl Pyrrolidone (PVP), were surface treated with either Vinyl Acetic acid (VAA) or Perfluorohexane (C6F14) using a low duty cycle pulsed plasma polymerization technique. The effects of this surface treatment on gas permeation properties of the PCTE were addressed. Plasma coating thickness was controllably varied and resulted in gradual reduction of O2 and CO2 permeability as thickness increased from 10nm to 100nm. Plasma coating material, permeant gas, membrane pore size, and crosslink density were also varied in order to gain insight into the permeation properties of the …

High-Resolution/High-Contrast Mri Of Human Articular Cartilage Lesions., Shadi F. Othman, Jun Li, Osama Abdullah, Jessy J. Moinnes, Richard L. Magin, Carol Muehleman

All Faculty Articles - School of Engineering and Computer Science

BACKGROUND: Magnetic resonance microscopy (MRM) is an important experimental tool in the identification of early cartilage lesions.

METHODS: Normal and degenerated cartilage samples were imaged at 11.74 T using a standard spin echo sequence. Quantitative MR measurements for T1, T2, and ADC were obtained and mapping for T2 and ADC was performed. The bi-exponential model for T2 relaxation was also explored. Histology was carried out for comparison with MR images.

RESULTS: MR images of cartilage samples displaying early stages of degeneration were positively correlated to their histological appearance in 23-microm high-resolution images and also with much shorter imaging times at …

Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Its Handling, Thermal, Physical, And Mechanical Properties, G. Lewis, J. Xu, S. Madigan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study is a contribution to the growing body of work on the influence of changes in the composition of an acrylic bone cement on various properties of the curing and cured material. The focus is on one commercially-available acrylic bone cement brand, Surgical Simplex®P, and three variants of it and a series of properties, namely, setting time, maximum exotherm temperature, activation energy and frequency factor for the polymerization reaction, diffusion coefficient for the uptake of phosphate buffered saline, at 37°C, ultimate compressive strength (UCS), plane-strain fracture toughness, fatigue life (under fully-reversed tension-compression stress), hardness (H) and elastic modulus (both …

Anwendung Von Interferenz- Und Ir-Mikroskopie Zur Charakterisierung Und Untersuchung Des Stofftransportes In Nanoporösen Materialien, Lars Heinke, Christian Chmelik, Pavel Kortunov, Sergey Vasenkov, Douglas M. Ruthven, Dhananjai B. Shah, Jörg Kärger

Chemical & Biomedical Engineering Faculty Publications

Die Anwendung der Interferenz-Mikroskopie bedeutet einen entscheidenden Durchbruch in der Untersuchung des Stofftransports von Gastmolekülen in nanoporösen Wirtsmaterialien. Diese Technik ermöglicht die Beobachtung der zeitaufgelösten intrakristallinen Konzentrationsprofile, die durch eine Änderung des umgebenden Gasdruckes entstehen. Dieser Ansatz wurde zur Untersuchung von Adsorptions- und Desorptionsprozessen in verschiedenen Zeolithsystemen verwendet. Die Vorteile dieser Technik, vor allem wenn sie mit Infrarotabsorptionsmessungen kombiniert wird, werden an Hand der experimentellen Resultate des Methanol-in-Ferrierit-Systems illustriert.

Influence Of Acid Washing On The Surface Morphology Of Ionomer Glasses And Handling Properties Of Glass Ionomer Cements, C. M. Crowley, J. Doyle, Mark R. Towler, N. Rushe, S. Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

Acid washing is known to influence the handling properties of ionomer glasses used in glass ionomer cements due to the production of an ion depleted zone on the surface of the glass particles. The influence of acid washing on the particle size distribution and surface area of four glasses was examined by scanning electron microscopy (SEM), particle size analysis (PSA) and accelerated surface area porosimetry (ASAP) and the working and setting times of cements, produced from the glasses, correlated to changes in surface morphology. A linear relationship was found between the specific surface area of acid-washed SiO₂-Al_{2 …}

Pulmonary Microvascular Injury Resulting From A Single Exposure To Low-Dose Thoracic Radiation, Q. Wu, G. Schmirler, John E. Moulder, Elizabeth R. Jacobs, Meetha Medhora, Robert C. Molthen

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Nitrogen And Phosphorus Concentrations Of Runoff As Affected By Moldboard Plowing, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The excessive application of manure on cropland areas can cause nutrients to accumulate near the soil surface. This study was conducted to measure the effects of moldboard plowing on the redistribution of nutrients within the soil profile and nutrient transport by overland flow. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha^-1 to a silty clay loam soil and then incorporated by disking. Selected plots were moldboard plowed 244 days later to a depth of approximately 23 cm. Soil samples for analysis of water‐soluble phosphorus, Bray and Kurtz No. 1 …

Nutrient Concentrations Of Runoff During The Year Following Manure Application, John E. Gilley, Bahman Eghball, D. B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Little information is currently available concerning temporal changes in nutrient transport following the addition of manure to cropland areas. This study was conducted to measure nutrient transport in runoff as affected by tillage and time following the application of beef cattle or swine manure to a site on which corn (Zea mays L.) was grown. Rainfall simulation tests were initiated 4, 32, 62, 123, and 354 days following land application. Three 30 min simulated rainfall events, separated by 24 h intervals, were conducted at an intensity of approximately 70 mm h-1. Dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus …

D-4f Does Not Mitigate Key Parameters In Rat Model Of Severe Pulmonary Hypertension, Robert C. Molthen, Shelley Baumgardt, K. A. Pritchard Jr

Biomedical Engineering Faculty Research and Publications

No abstract provided.