Biomedical Engineering and Bioengineering Commons^™

The Development Of An In Vivo Spinal Fusion Monitor Using Microelectromechanical (Mems) Technology To Create Implantable Microsensors, Lisa Anne Ferrara

ETD Archive

Surgical fusion of the spine is a conventional approach, and often last alternative, to the correction of a degenerative painful spinal segment. The procedure involves the surgical removal of the intervertebral disc at the problematic site, and the placement of a bone graft that is commonly harvested from the patients iliac crest and placed within the discectomized space. The surrounding bone is expected to incorporate and remodel into the bone graft to eventually provide an immobilized site. Spinal instrumentation often accompanies the bone graft to provide further immobility to the targeted site, thus augmenting the fusion process. However, the status …

Relationship Between Arch Height And Midfoot Joint Pressures During Gait, Dong Gil Lee

ETD Archive

A foot arch is a multi-segmented curved structure which acts as a spring during locomotion. It is well known that ligaments are important components contributing to this spring-like property of the arch. In addition, intrinsic and extrinsic foot muscles contribute to arch support. According to the windlass foot model, arch height and midfoot joint orientation change during gait. However, it is not known whether altered joint configurations result in increased joint stress during gait. If so, it is possible for there to be a "vicious cycle" in which joint stress increases as the arch height diminishes, which may then lead …

Generation Of Recombinant Mouse Embryonic Stem Cell Lines And Theirapplication For In Vivo Bioluminiscence Imaging In The Heart, Ramana Kammili

Electronic Theses and Dissertations

Cardiovascular disease is the major cause of death in the United States, with 80 million people suffering from some form of heart disease each year. One major limitation is the inability of the heart to repair the damaged tissue. Stem cell therapy holds enormous promise to repair and regenerate the damaged myocardium, but there are many technical difficulties that must first be overcome. One such difficulty is the present lack of ability to track and assess transplanted stem cells over time in vivo. The central hypothesis of this thesis is that in vivo bioluminescence imaging is a safe and useful …

Mems Transducer For Hearing Aid Device, Houwen Tang

Electronic Theses and Dissertations

A study of implantable middle ear MEMS piezoelectric transducer for hearing aids was developed. The physical vibration deflection at the tip of the transducer is simulated using finite element method. Further, a study of thermoelastic damping effect of four designed MEMS mirrors used as resonators is presented. An optical measurement system based on Mach-Zehnder interferometer is

Microfluidic Devices For Terahertz Spectroscopy Of Biomolecules, P. A. George, W. Hui, F. Rana, Benjamin G. Hawkins, A. E. Smith, B. J. Kirby

Faculty Publications

We demonstrate microfluidic devices for terahertz spectroscopy of biomolecules in aqueous solutions. The devices are fabricated out of a plastic material that is both mechanically rigid and optically transparent with near-zero dispersion in the terahertz frequency range. Using a low-power terahertz time-domain spectrometer, we experimentally measure the absorption spectra of the vibrational modes of bovine serum albumin from 0.5–2.5 THz and find good agreement with previously reported data obtained using large-volume solutions and a high-power free-electron laser. Our results demonstrate the feasibility of performing high sensitivity terahertz spectroscopy of biomolecules in aqueous solutions with detectable molecular quantities as small as …

Experimental And Numerical Investigation Of Wire Waveguides For Therapeutic Ultrasound Angioplasty, Declan Noone (Thesis)

Other resources

Therapeutic ultrasound angioplasty is an emerging minimally invasive cardiovascular procedure for disrupting atherosclerotic lesions using small diameter wire waveguides. The lesions are damaged through a combination of direct ablation, pressure waves, cavitation and acoustic streaming caused by distal-tip displacements at ultrasonic frequencies. Numerical and experimental methods are used to investigate the outputs of the wire waveguides during ultrasonic activation. A commercially available generator and acoustic horn are used in combination with Nickel-Titanium (NiTi) wire waveguides in this study. A laser sensor is used to measure the frequency and amplitude output of the distal tip of the wire waveguide, and this …

Characterization Of Changes In Hyaluronan Following Epidermal Barrier Injury In An Organotypic Model, Gati Ajani

ETD Archive

The stratum corneum, the outermost layer of the epidermis of skin, provides a functional permeability barrier that is essential for our survival and must be rapidly repaired after injury. Of interest to us, a ubiquitous matrix molecule called hyaluronan (HA) has come to the forefront in wound healing research because it is induced after epidermal injury and may be crucial for barrier repair. This thesis examines the role of HA during recovery from the most fundamental form of skin injury, i.e. selective damage to the stratum corneum. The overall question is whether this form of stratum corneum injury can lead …

Novel Antifreeze Protein Constructs For Improved Activity, Ozge Can

ETD Archive

Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low …

Fabrication Of Nanostructured Metals And Their Hydrogen Storage Properties, Asli Ertan

ETD Archive

Searching for new energy sources is highly desirable for the next generations when rapidly changing factors are considered such as population, increasing pollution and exhaustion of fossil fuels. Hence, there is a need for clean, safe and efficient energy carriers or forms of energy that can be transported to the end user. One of these energy carriers is electricity which has been used widely and can be produced from various sources. However, its production from fossil fuels contributes to pollution. On the other hand hydrogen, due to its abundance, light weight, low mass density, high energy density and non-polluting nature …

Mems (Micro-Electro-Mechanical-Systems) Based Microfluidic Platforms For Magnetic Cell Separation, Pulak Nath

ETD Archive

Microfluidic platforms for magnetic cell separation were developed and investigated for isolation of magnetic particles and magnetically tagged cells from a fluidic sample. Two types of magnetic separation platforms were considered: an Isodynamic Open Gradient Magnetic Sorter (OGMS) and a multistage bio-ferrograph. Miniaturized magnets were designed using magnetostatic simulation software, microfluidic channels were fabricated using microfabrication technology and magnetic separation was investigated using video microscopy and digital image processing. The isodynamic OGMS consisted of an external magnetic circuit and a microfabricated channel (biochip) with embedded magnetic elements. The biochip is placed inside the magnetic field of the external circuit to …

Bio-Signal Analysis In Fatigue And Cancer Related Fatigue;Weakening Of Corticomuscular Functional Coupling, Qi Yang

ETD Archive

Fatigue is a common experience that reduces productivity and increases chance of injury, and has been reported as one of most common symptoms with greatest impact on quality-of-life parameters in cancer patients. Neural mechanisms behind fatigue and cancer related fatigue (CRF) are not well known. Recent research has shown dissociation between changes in brain and muscle signals during voluntary muscle fatigue, which may suggest weakening of functional corticomuscular coupling (fCMC). However, this weakening of brain-muscle coupling has never been directly evaluated. More important information could be gained if fCMC is directly detected during fatigue because a voluntary muscle contraction depends …

A Novel Cardiac Pacing Paradigm For Atrial Fibrillation And Heart Failure Patients, George Emanuel Yanulis

ETD Archive

It has been estimated that 4.6 million persons have heart failure, and 400,000 to 700,000 new cases develop each year and the U.S. Hospital discharges for HF rose from 399,000 in 1979 to 1,099,000 in 2004 according to the National Hospital Discharge Survey. Atrial fibrillation is the most common sustained cardiac arrhythmia in the United States. Recent studies have demonstrated that ventricular rate control is a viable treatment strategy for patients in atrial fibrillation. In a number of cases, despite the electrical resynchronization of the ventricles using biventricular pacing (cardiac resynchronization therapy), heart failure patients in sinus rhythm do not …

Biocompatibility Of Osteoblast Cells On Titanium Implants, Dilip Ayyala Somayajula

ETD Archive

Adhesion and proliferation of UMR 106-01 osteoblast cells were studied on various surface modified titanium materials such as polished, sandblasted, anodized and alkaline treated. Anodization of polished surface in Hydrofluoric acid developed nano-tubes, while NaOH treatment produced spongy microporous morphology. Test samples were coated with non-adhesive protein bovine serum albumin and compared with fibronectin coated specimens. The adhesion study lasted for 4 hrs, where osteoblast cells were cultured in serum free medium. Polished titanium, anodized titanium and NaOH titanium have shown similar percentages of cell adherence. The proliferation study lasted for 48 hrs, where cells were initially allowed to adhere …

Slurry Based Coatings On Silicon Based Ceramics, Sameer K. Khaja-Abdul

ETD Archive

The use of advanced structural ceramics, such as Si3N4 (SN282), SiC, and SiC/SiC composites, is a promising technology to accomplish the high performance goals for advanced turbine applications. These materials exhibit excellent corrosion resistance by forming a dense silica scale. However, severe degradation of the silica scale has been observed due to the presence of certain environmental species, like alkali salts and water vapors, limiting the long-term reliability of structural ceramics. Presence of water vapor in the turbine environment leads to the formation of a gaseous silicon hydroxide species (Si(OH)4) via a reaction with silica layer, SiO2(s) + 2H2O(g) = …

Nonlinear State Estimation In Polymer Electrolyte Membrane Fuel Cells, Uma Tumuluri

ETD Archive

Research on alternative and renewable energy sources which are amicable to the environment has gained momentum because of the growing concern about the tremendous increase in the concentration of toxic and green house gases and scarcity of the fossil fuels. Among the available renewable sources, fuel cell technology has received a high research attention due to their high efficiency and superior reliability. Among the various fuel cells available, Polymer electrolyte membrane fuel cell is promising source for both stationary and mobile applications because of its high efficiency and low operating temperatures. The performance of the fuel cell depends on the …

Computational Modeling Of Oxidative Stress: An Analysis Of Nad(P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel

Inquiry: The University of Arkansas Undergraduate Research Journal

Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (02-). This reaction forms peroxynitrite (ONOO). Superoxide is produced in the cardiac system by several mechanisms, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension.

Self-Assembly Of A Micrometers-Long One-Dimensional Network Of Cemented Au Nanoparticles, Vivek C. Maheshwari, Jennifer Kane, Ravi F. Saraf

Ravi Saraf Publications

One-dimensional Au nanoparticles connected by ionic linkers self-assemble into a micrometer-scale network. Reactions between linker ions reinforce the assembly and lead to the formation of a continuous network. This continuous network demonstrates room temperature Coulomb-blockade characteristics that are indicative of electron transport along the 1D pathways.

Optimization Of Reconstruction Parameters In Brain Activation Studies, Aswini Kanneganti

Bioengineering Theses - Archive

Diffuse Optical Imaging (DOI) is being extensively used in brain activation studies for the quantification of hemodynamic changes in the cerebral cortex. Many investigators have utilized the commercially available CW5 DOI device to attain cortical activation maps. However, the localization and spatial resolution in the resulting activation images remains poor. These limitations arise due to the large source detector separations required for light to reach the brain's surface and the limited number of detector channels in the CW5 system, which result in sparse spatial sampling of the cortical activation regions. In this thesis we assess the feasibility of using denser …

Feasibility Study Of An Ultra Fast Gated Camera To Image Biliary Tree Embedded In Adipose Tissue Using Laboratory Phantoms And Monte Carlo Simulations, Nimit Lalitkumar Patel

Bioengineering Theses - Archive

Every year, approximately 500,000 cholecystectomies are performed in US. As biliary tree structures are embedded in adipose tissue, they cannot be visualized directly by the surgeon, which causes inadvertent injuries to the common bile duct, vein and artery during a laparoscopic cholecystectomy. Thus there is an urge for an imaging modality which could see biliary tree structure through fatty tissue. Successful clinical implementation of an imaging system which could attain this goal would reduce surgical time, improve patient safety and minimize the risk of complications and expenses attributable to the current standard practice of intraoperative cholecystectomy. It is hoped that …

Automated Quantification Of White Matter Hyperintensity Burden Using Mprage And Flair Images From A Large Population, Keith Mcleod Hulsey

Bioengineering Theses - Archive

White Matter Hyperintensity(WMH) burden, as observed in T2 and proton weighted MR images, is associated with several health factors such as decreased cognitive ability, hypertension, diabetes and cerebrovascular disease. An algorithm was developed to automatically estimate WMH burden from pairs of MPRAGE and FLAIR images which is robust and requires essentially no operator involvement. The WMH burden estimation generated by this fully automated algorithm has been shown to correlate well with known risk factors for WMH burden.

Synthesis And Characterisation Of Raman Nanotags For Molecular Detection, James Otieno Nyagilo

Bioengineering Theses - Archive

The realization that most diseases are preceded or accompanied by changes in the genetic and cellular level of an organism has increased with the need for imaging modalities, with the sensitivity and specificity, to quantitatively detect biomolecules at those levels. Specifically there has been a need for the development of a modality that has the ability to detect multiple biomolecules from a single sample in order to increase accuracy of molecular diagnosis and allow for early detection of terminal diseases. Surface enhanced Raman spectroscopy provides potential for such a modality. The distinct spectrum of each Raman active molecule serves as …

Visible To Near Infra Red Hyperspectral Imaging: Visualizing The Neurological And Biological Nature Of Ischemic Tissue, Swetha Suresh

Bioengineering Theses - Archive

Diabetic Neuropathy is a neuropathic disorder which is associated with Diabetes Mellitus. It is known to result in lower limb ulcers which can lead to amputation. Nerve damage, microvascular dysfunctions and use of ill fitting shoes are significant causes for it. These abnormal dysfunctions can lead to Ischemia. We have used the Multimodal Hyperspectral Imaging System image areas of high pressure on the skin that correspond to pain and also to visualize vascular changes that are associated with this pain. The instrument majorly consists of near-infrared and visible charge coupled devices (CCDs), lenses, liquid crystal tunable filters (LCTFs) for both …

Pyrene Fate Affected By Humic Acid Amendment In Soil Slurry Systems, Y. Liang, D. Sorensen, Ronald C. Sims, Joan Mclean

Biological Engineering Faculty Publications

Background

Humic acid (HA) has been found to affect the solubility, mineralization, and bound residue formation of polycyclic aromatic hydrocarbons (PAHs). However, most of the studies on the interaction between HA and PAH concentrated on one or two of the three phases. Few studies have provided a simple protocol to demonstrate the overall effects of HA on PAH distribution in soil systems for all three phases.

Methods

In this study, three doses of standard Elliott soil HA (ESHA), 15, 187.5, and 1,875 μg ESHA/g soil slurry, were amended to soil slurry systems. ¹⁴C-pyrene was added to the systems along …

High Temperature Dilute Acid Pretreatment Of Coastal Bermudagrass, Arthur Redding, Deepak R. Keshwani, Ziyu Wang, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

The conversion of lignocellulosic biomass into ethanol is an encouraging technology in the face of concerns over global warming and finite energy resources. In the southeastern United States, coastal bermudagrass shows potential for use as an energy crop for ethanol production. A review of the literature has shown that research has been done on the dilute sulfuric acid pretreatment of costal bermudagrass at 121ºC prior to enzymatic hydrolysis. This study examined dilute acid concentrations of 0.3%(w/w) to 1.2%(w/w) at temperatures from 120ºC to 180ºC over residence times of 5 to 60 minutes in an effort to optimize the pretreatment process …

Preparation And Characterization Of Tapioca Starch-Poly(Lactic Acid)-Cloisite Na+ Nanocomposite Foams, Siew-Yoong Lee, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tapioca starch, poly(lactic acid), and Cloisite NA⁺ nanocomposite foams, with four clay contents (1, 3, 5, 7, wt %), were prepared by melt-intercalation method. Selected structural, thermal, physical, and mechanical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy, differential scanning calorimetry, and an Instron universal testing machine, respectively. XRD results indicated that the 1 wt % nanocomposite foam did not show the characteristic basal reflection of the nanoclay. The 3, 5, and 7 wt % nanocomposite foams produced a mixture of intercalated and tactoid structures. The d₀₀₁-spacing of 3, 5, 7 wt % nanocomposite foams …

Comparison Of Lipid Extraction Methods Of Food-Grade Sorghum (Sorghum Bicolor) Using Hexane, K. L. Christiansen, Curtis L. Weller, V. L. Schlegel, I. M. Dweikat

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Much has been reported concerning sorghum phytochemicals, such as policosanols, but little literature exists on how various extraction methods might be used to optimize the recovery of such phytochemicals. The purpose of this study was to compare three extraction methods for recovery of different sorghum lipids. Lipids were extracted from whole kernel and ground Macia, a food-grade sorghum hybrid, with hexane by a Soxtec method, a refluxing method (RB), and a bench-scale recirculated solvent (RC) method. Comparisons of total lipid yield and lipid class yields extracted from the grain by each method were made. Total lipid yield for the three …

Field Slope Effects On Uniformity Of Corn Seed Spacing For Three Precision Planter Metering Systems, Corey L. Searle, Michael F. Kocher, John A. Smith, Erin E. Blankenship

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of field slope on planter seed spacing uniformity were evaluated for three different seed metering units (cell plate, finger pick‐up, and flat plate) operating with medium round corn seed in a laboratory using the University of Nebraska planter test stand with an opto‐electronic seed spacing sensor system. The metering units included a John Deere MaxEmerge™ Plus VacuMeter row unit with the standard cell corn plate, a John Deere MaxEmerge™ Plus VacuMeter row unit with the flat plate, and a John Deere MaxEmerge™ Plus row unit with the finger pick‐up metering system. Planter seed spacing uniformity was measured using …

Surface Polyethylene Glycol Enhances Substrate-Mediated Gene Delivery By Nonspecifically Immobilized Complexes, Angela K. Pannier, Julie A. Wieland, Lonnie D Shea

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Substrate-mediated gene delivery describes the immobilization of gene therapy vectors to a biomaterial, which enhances gene transfer by exposing adhered cells to elevated DNA concentrations within the local microenvironment. Surface chemistry has been shown to affect transfection by nonspecifically immobilized complexes using self-assembled monolayers (SAMs) of alkanethiols on gold. In this report, SAMs were again used to provide a controlled surface to investigate whether the presence of oligo(ethylene glycol) (EG) groups in a SAM could affect complex morphology and enhance transfection. EG groups were included at percentages that did not affect cell adhesion. Nonspecific complex immobilization to SAMs containing combinations …

Visible/Near-Infrared Hyperspectral Imaging For Beef Tenderness Prediction, Govindarajan Konda Naganathan, Lauren M. Grimes, Jeyamkondan Subbiah, Chris R. Calkins, Ashok Samal, George E. Meyer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Beef tenderness is an important quality attribute for consumer satisfaction. The current beef quality grading system does not incorporate a direct measure of tenderness because there is currently no accurate, rapid, nondestructive method for predicting tenderness available to the beef industry. The objective of this study was to develop and test a visible/nearinfrared hyperspectral imaging system to predict tenderness of 14-day aged, cooked beef from hyperspectral images of fresh ribeye steaks acquired at 14-day post-mortem. A push-broom hyperspectral imaging system (wavelength range: 400-1000 nm) with a diffuse-flood lighting system was developed and calibrated. Hyperspectral images of beef-steak (n = 111) …

Characterization Of Radio Frequency Heating Of Fresh Fruits Influenced By Dielectric Properties, Sohan Birla, S. Wang, Juming Tang, G. Tiwari

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Because of its fast and volumetric nature, radio frequency (RF) heating has been looked upon as a way to overcome the problems associated with conventional heating methods used for disinfestation of fruits. But non-uniform heating within fruits is a major obstacle in adaptation of this technology. In this study, RF heating patterns influenced by dielectric properties (DPs) of fruits were investigated both experimentally and mathematically. A computer simulation model was developed using FEMLAB 3.4, a commercial software for solving Maxwell’s electromagnetic and Fourier’s heat transfer equations. Orange, apple, grapefruit, peach, and avocado fruits, selected for these studies were subjected to …