Biomedical Engineering and Bioengineering Commons^™

The Development Of A Mesenchymal Stem Cell Based Biphasic Osteochondral Tissue Engineered Construct, Scott Maxson

All Dissertations

The ability of human articular cartilage to respond to injury is poor. Once cartilage damage has occurred, an irreversible degenerative process can occur and will often lead to osteoarthritis (OA). An estimated 26.9 million of U.S. adults are affected by OA. Osteochondral grafting is currently used to treat OA and osteochondral defects; however, complications can develop at the donor site and defect area. Osteochondral tissue engineering provides a potential treatment option and alternative to osteochondral grafting. The long term goal of this work is to develop a tissue engineered mesenchymal stem cell (MSC) based osteochondral construct to repair cartilage damage. …

Incorporation Of Vascular Endothelial Growth Factor And Pleiotrophin Into A Multiluminal Biosynthetic Nerve Implant For The Repair Of Peripheral Nerve Long Gap Defects, An Hai Nguyen

Bioengineering Theses - Archive

To repair a fully transected nerve without putting undue tension on the nerve stumps, and too circumvent many of the obvious problems of using harvested nerve grafts synthetic nerve guides have been used in the clinical setting. Thus far this strategy has met with minimal success for the repair of short defects (i.e. 1 - 2.5 cm) while any defect larger than 3 cm have failed. We hypothesize that neurotorphic support, early vascularization, and contact guidance are needed to successfully regenerate a nerve across a long-gap defect. To this end we proposed a biosynthetic nerve implant (BNI) with a multiluminal …

Distraction Osteogenesis In An Organ Culture Model, Bradley R. Heil

University of Kentucky Master's Theses

Distraction osteogenesis (DO) is a surgical procedure in which applied strain stimulates new bone growth; however, the underlying mechanisms by which bone cells respond to load are still uncertain. An organ culture model of DO was developed and validated by using linear distraction on the femoral shafts of 5 day old Wistar rats. Two loading regimes were utilized: distracting the bones for 2 hrs on day 1 (GRP I); distracting the bones for 2 hrs on days 1, 3, and 5 (GRP II). After 1 week in culture, the bones were compared to unloaded contralateral controls and assessed for changes. …

Testing Fuel Efficiency Of Tractors With Both Continuously Variable And Standard Geared Transmissions, Christopher N. Howard

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

A John Deere 8295R IVT tractor with a continuously variable transmission (CVT) and a John Deere 8295R PowerShift (PST) tractor (Waterloo, Iowa) with a standard geared transmission (GT) were tested for fuel consumption at three different travel speeds with six different load levels applied per speed. The JD 8295R PST tractor was tested both at full throttle (FT) and shifted up two gears and throttled back (SUTB) to achieve the same travel speed as at full throttle conditions. The three speeds tested corresponded to the maximum speeds achieved in 6th, 8th and 10th gear for the JD 8295R PST tractor …

Impaired Vascular Reactivity Following Chronic Ischemia In The Arteries Of The Mouse Hindlimb, Thomas (Tom) Kesler

Biomedical Engineering

Collateral dependent hyperemia is reduced following chronic ischemia, but the contribution of individual vessel reactivity is unknown. Further, it is not known what aspect of the complex ischemic injury response impacts vascular reactivity. To determine the impact of ischemia on vascular reactivity, we measured functional vasodilation in the muscular branch artery following resection of the femoral artery proximal to the muscular branch. On day-14 after surgery the diameter of the muscular branch was measured using side-stream dark field (SDF) imaging intravital microscopy. At moderate intensity skeletal muscle contraction (1mA, 200µs, 8Hz, 90sec), functional vasodilation is reduced compared to the contralateral …

Morphological Assessment Of Basic Multicellular Unit Resorption Parameters In Dogs Shows Additional Mechanisms Of Bisphosphonate Effects On Bone, Matthew R. Allen, Antonia M. Erickson, Xiang Wang, David B. Burr, R. Bruce Martin, Scott J. Hazelwood

Biomedical Engineering

Bisphosphonates (BPs) slow bone loss by reducing initiation of new basic multicellular units (BMUs). Whether or not BPs simply prevent osteoclasts from initiating new BMUs that resorb bone or also reduce the amount of bone they resorb at the BMU level is not clear. The goal of this study was to determine the effects of BPs on three morphological parameters of individual BMUs, resorption depth (Rs.De), area (Rs.Ar), and width (Rs.Wi). After 1 year of treatment with vehicle (VEH), alendronate (ALN; 0.10, 0.20, or 1.00 mg/kg/day), or risedronate (RIS; 0.05, 0.10, or 0.50 mg/kg/day), resorption cavity morphology was assessed in …

Impaired Vascular Reactivity Following Chronic Ischemia In The Arteries Of The Mouse Hindlimb, Trevor Cardinal, Thomas J. Kesler, Matthew D. Yocum, Tyler S. Smith, Nolan M. Mott

Biomedical Engineering

No abstract provided.

Sodium Hydroxide Pretreatment And Enzymatic Hydrolysis Of Coastal Bermuda Grass, Ziyu Wang, Deepak R. Keshwani, Arthur P. Redding, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Coastal Bermuda grass was pretreated with NaOH at concentrations from 0.5% to 3% (w/v) for a residence time from 15 to 90 minutes at 121 °C. The pretreatments were evaluated based on total lignin removal and production of total reducing sugars, glucose and xylose from enzymatic hydrolysis of the pretreated biomass. Up to 86% lignin removal was observed. The optimal NaOH pretreatment conditions at 121 °C for total reducing sugars production as well as glucose and xylose yields are 15 minutes and 0.75% NaOH. Under these optimal pretreatment conditions, total reducing sugars yield was about 71% of the theoretical maximum, …

Frustrated Drift Of An Anchored Scroll-Wave Filament And The Geodesic Principle, Marcel Wellner, Christian W. Zemlin, Arkady M. Pertsov

Bioelectrics Publications

We investigate anchored scroll-wave filaments in an excitable medium whose diffusivity matrix, including its determinant, is spatially nonuniform. The study is motivated by cardiological applications where scroll-wave behavior in the presence of diffusivity gradients is believed to play an important role in the development of severe arrhythmias. A diffusivity gradient is expected to make the filament drift, unless drift is prevented ("frustrated") by anchoring to localized defects in the propagation medium. The resulting stationary filament is a geodesic curve, as demonstrated here in the case of a nonzero but constant gradient. That is, the diffusivity matrix has a determinant that …

The Influence Of Hydrogen Peroxide On The Static And Fatigue Properties Of Palacos-R Bone Cement, John M. Guerin

Theses

Aseptic loosening is a very costly complication of joint arthroplasty, both in terms of patient quality of life and financially. One potential contributing factor in its development - namely the use of hydrogen peroxide as an effervescent haemostatic agent - was investigated in this study. Clean bone cement samples and samples contaminated with 6% hydrogen peroxide were manufactured and stored either in room air or normal saline prior to testing. Thus four sample types were tested (clean stored wet or dry and contaminated stored wet or dry). Static (tension to failure) and fatigue testing was performed. Analysis was carried out …

Composition-Structure-Property Relationships In Multicomponent Bioactive Glasses, Sharon Murphy

Theses

Silicate glasses function effectively as bone grafts by stimulating bone regeneration through gene activation. However these materials offer little therapeutic potential for the regeneration of healthy bone in those suffering from metabolic bone diseases such as osteoporosis. Examining the composition-structure-property relationships arising from the incorporation of therapeutic ions such as strontium (Sr) and zinc (Zn) into such glasses in order to allow for healthy bone regeneration and antibacterial efficacy, as well as sodium (Na) to allow for controlled ion release was the objective of this work. Eight calcium-strontium-sodium-zinc-silicate glass compositions were produced, based on incremental additions of Sr and Na. …

Prostate Cancer Region Prediction Using Maldi Mass Spectra, Ayyappa Vadlamudi, Shao-Hui Chuang, Xiaoyan Sun, Lisa Cazares, Julius Nyalwidhe, Dean Troyer, O. John Semmes, Jiang Li, Frederic D. Mckenzie

Electrical & Computer Engineering Faculty Publications

For the early detection of prostate cancer, the analysis of the Prostate-specific antigen (PSA) in serum is currently the most popular approach. However, previous studies show that 15% of men have prostate cancer even their PSA concentrations are low. MALDI Mass Spectrometry (MS) proves to be a better technology to discover molecular tools for early cancer detection. The molecular tools or peptides are termed as biomarkers. Using MALDI MS data from prostate tissue samples, prostate cancer biomarkers can be identified by searching for molecular or molecular combination that can differentiate cancer tissue regions from normal ones. Cancer tissue regions are …

Destruction Of Α -Synuclein Based Amyloid Fibrils By A Low Temperature Plasma Jet, Erdinc Karakas, Agatha Munyanyi, Lesley Greene, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the plasma pencil, a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

Testing Of Rtk-Level Satellite-Based Tractor Auto-Guidance Using A Visual Sensor System, Dwight Easterly, Viacheslav I. Adamchuk, Roger M. Hoy, Michael F. Kocher

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The use of satellite-based positioning has advanced considerably in the world of agriculture, providing a range of technical solutions that include the automated steering of tractors and self-propelled machinery. With the development of auto-guidance systems comes the need to evaluate their performance. Given that current precision and accuracy claims are relatively small in magnitude, it is imperative there be a testing system capable of detecting errors with ten times greater accuracy-- possibly as little as a few millimeters. A visual sensor was adopted to achieve this level of measurement resolution. The sensor was used to determine the cross-track error estimates …

Theory Of ‘Selectivity’ Of Label-Free Nanobiosensors – A Geometro-Physical Perspective, Pradeep R. Nair, Muhammad A. Alam

Birck and NCN Publications

Modern label-free biosensors are generally far more sensitive and require orders of magnitude less incubation time compared to their classical counterparts. However, a more important characteristic regarding the viability of this technology for applications in Genomics/Proteomics is defined by the ‘Selectivity’, i.e., the ability to concurrently and uniquely detect multiple target biomolecules in the presence of interfering species. Currently, there is no theory of Selectivity that allows optimization of competing factors and there are few experiments to probe this problem systematically. In this article, we use the elementary considerations of surface exclusion, diffusion limited transport, and void distribution function to …

Anterior-Posterior Impedance Cardiography: A New Approach To Accurate, Non-Invasive Monitoring Of Cardiac Function, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The conventional impedance cardiogram is a record of pulsatile changes in the electrical impedance of the chest with each heartbeat. The signal seems intuitively related to cardiac stroke volume. However doubts persist about the validity of stroke volume measurements based on electrical impedance. This paper presents a new electrical axis for impedance cardiography that is perpendicular to the conventional head-to-foot axis in an anterior-posterior direction. Dual chest and back electrodes are concentric, permitting tetrapolar technique. A relatively simple analytical model is developed, and this model is validated in a three-dimensional finite element model of current flow through the human chest. …

Imaging The Vasculature With Susceptibility Weighted Imaging: Applications And Analysis, Samuel Barnes

Wayne State University Dissertations

Modern magnetic resonance imaging sequences allow detailed non-invasive imaging of both the arteries and veins. This work is divided into four sections that examine different applications and analysis of these sequences.

Susceptibility weighted imaging (SWI) typically generates excellent negative venous contrast. Techniques to generate positive arterial contrast in SWI images without degrading the venous contrast with a single echo are examined. By using high isotropic resolution and high readout bandwidth flow losses can be minimized (generating good arterial contrast) even at the long echo times required for good venous contrast. A downsampling filter is then used to restore lost venous …

Implementation Of Risk Management In The Medical Device Industry, Rachelo Dumbrique

Master's Theses

This study looks at the implementation and effectiveness of risk management (RM) activities in the medical device industry. An online survey was distributed to medical device professionals who were asked to identify RM-related activities performed during the device life cycle. RM activities and techniques included Establishing Risk Acceptance Criteria, Hazard Identification, Human Factors/Usability, Fault Tree Analysis (FTA), Design Failure Mode and Effects Analysis (DFMEA), Process Failure Mode and Effects Analysis (PFMEA), Hazard and Operability Study (HAZOP), Hazard Analysis and Critical Control Point (HACCP), Risk Benefit Analysis, and Risk Assessment of Customer Complaint. Devices were identified by type (therapeutic, surgical/clinical tools, …

Extent And Effects Of Selection To Reduce Synthetic Cost Of Highly Expressed Proteins, Esley Marvin Heizer Jr

Browse all Theses and Dissertations

Organisms that preferentially utilize less biosynthetically expensive amino acids in highly expressed genes exhibit metabolic efficiency. Exploration of this phenomenon has been limited to six prokaryotes.

I present a large scale analysis of metabolic efficiency in prokaryotic organisms and analysis of two eukaryotes (Saccharomyces cerevisiae and humans). Examination of 73 bacteria reveals the presence of metabolic efficiency in 66 organisms. The average correlation between amino acid biosynthetic cost and CAI scores in these organisms is -0.21. The seven organisms that did not exhibit metabolic efficiency are all Lactobacilli and highly auxotrophic. Saccharomyces cerevisiae exhibits significant trends between average amino acid …

Population Fit Threshold: Fully Automated Signal Map Generation For Baseline Correction In Nmr-Based Metabolomics, Daniel C. Homer

Browse all Theses and Dissertations

Baseline correction of NMR-based metabolomic spectra is a key step in data processing to elucidate biomarkers of diseased and toxic states. Automated baseline correction methods often use human-selected parameters. Presented is a method for automated baseline correction using parameters selected from and without manipulation of the spectrum. The focus is on generating an accurate signal map based on the differentiating characteristics of baseline noise and signal. The presented method of signal map generation and baseline correction was developed and tested on 13C and 1H NMR spectra. The spectra were as simple as chemical standards containing less than 25 signal peaks …