Engineering Commons^™

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 …

Il-21 Limits Peripheral Lymphocyte Numbers Through T Cell Homeostatic Mechanisms., Shrimati Datta, Nora E. Sarvetnick

Journal Articles: Regenerative Medicine

BACKGROUND: IL-21, a member of the common gamma-chain utilizing family of cytokines, participates in immune and inflammatory processes. In addition, the cytokine has been linked to autoimmunity in humans and rodents.

METHODOLOGY/PRINCIPAL FINDINGS: To investigate the mechanism whereby IL-21 affects the immune system, we investigated its role in T cell homeostasis and autoimmunity in both non-autoimmune C57BL/6 and autoimmune NOD mice. Our data indicate that IL-21R knockout C57BL/6 and NOD mice show increased size of their lymphocyte population and decreased homeostatic proliferation. In addition, our experimental results demonstrate that IL-21 inhibits T cell survival. These data suggest that IL-21 acts …

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 …

The Highly Similar Arabidopsis Homologs Of Trithorax Atx1 And Atx2 Encode Proteins With Divergent Biochemical Functions, Abdelaty Saleh, Raul Alvarez-Venegas, Mehtap Yilmaz, Oahn-Le, Guichuan Hou, Monther Sadder, Ayed Al-Abdallat, Yuannan Xia, Guoqinq Lu, Istvan Ladunga, Zoya Avramova

Nebraska Center for Biotechnology: Faculty and Staff Publications

Gene duplication followed by functional specialization is a potent force in the evolution of biological diversity. A comparative study of two highly conserved duplicated genes, ARABIDOPSIS TRITHORAX-LIKE PROTEIN1 (ATX1) and ATX2, revealed features of both partial redundancy and of functional divergence. Although structurally similar, their regulatory sequences have diverged, resulting in distinct temporal and spatial patterns of expression of the ATX1 and ATX2 genes. We found that ATX2 methylates only a limited fraction of nucleosomes and that ATX1 and ATX2 influence the expression of largely nonoverlapping gene sets. Even when coregulating shared targets, ATX1 and ATX2 may employ different …

Orthogonal Cutting Of Bone, Donal Mccrohan

Theses

The cutting of bone has been undertaken for many centuries. Research in this area is contnually progressing to achieve an efficient cutting action while reducing recovery time and rauma to the patient.

Orthogonal cutting is defined where the cutting edge of the tool is set in a position that is perpendicular to the direction of relative work or tool motion. The failure mechanisms involved in the cutting of bone, their direct relationships to cutting tool geometry and cutting direction for orthogonal cutting are not accurately defined or quantified. A study of the orthogonal cutting behaviour of bone initiated in the …

Electric-Powered Wheelchairs As An Assistive Technology, Aidan O'Dwyer, Malabika Basu, Eugene Coyle

Conference papers

This paper briefly outlines recent work done, particularly in control systems, for electric powered wheelchairs. These mobility aids, first developed in the 1950’s [1], were improved with the incorporation of microprocessors. The requirement for mobility aids in general is rising; for example, it is reckoned that 1.5% of the U.K. population require such aids. As an assistive technology, electric powered wheelchairs have many benefits. Nevertheless, a reliable and robust such wheelchair has still to evolve.

Augmented Control Of Hands Free Voice Prostheses, Brian Madden, James Condron, Ted Burke, Eugene Coyle

Conference Papers

Laryngectomy patients often use an electrolarynx to facilitate speech following a tracheotomy. Devices of this type provide the most intelligible means of communication for tracheotomy patients. However, the electro-larynx has inherent drawbacks such as the buzzing monotonic sound emitted, the need for a free hand to operate the device, and the difficulty experienced by many tracheotomy patients in adapting to use it. The most effective means of addressing the shortcomings of existing electro-larynges is to provide the user with a hands-free facility. This allows the user to perform other manual tasks whilst speaking, or simply to communicate more effectively through …

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 …

Balance Performance Measurment In A Phase Shifted Feedback Environment, Craig Alan Hoovler

Theses and Dissertations

Commercial technologies for the objective assessment of balance exist in clinical settings. Training requires integration of sensory information to produce a coordinated motor response related to balance. These systems have had measurable phase delays of up to 250ms in the visual feedback provided to the patient. This provokes an unnatural response, requiring prediction from the subject. The proposed research investigates the impact of visual feedback phase delays on the performance of weight shift tracking tasks in a population of individuals with no known balance deficits.Visual feedback delays were investigated by simulating popular balance training software which utilizes force plates to …

Detailed Characterization Of The Mouse Embryonic Stem Cell Transcriptome Reveals Novel Genes And Intergenic Splicing Associated With Pluripotency, Galih Kunarso, Kee-Yew Wong, Lawrence W. Stanton, Leonard Lipovich

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Transcriptional control of embryonic stem (ES) cell pluripotency has been a subject of intense study. Transcriptional regulators including Oct4 (Oct3/4 index), Sox2 and Nanog are fundamental for maintaining the undifferentiated state. However, the ES cell transcriptome is not limited to their targets, and exhibits considerable complexity when assayed with microarray, MPSS, cDNA/EST sequencing, and SAGE technologies. To identify novel genes associated with pluripotency, we globally searched for ES transcripts not corresponding to known genes, validated their sequences, determined their expression profiles, and employed RNAi to test their function.

Results

Gene Identification Signature (GIS) analysis, a SAGE derivative distinguished …

Mechanism Of Nanoparticle And Nanotube-Induced Cell Death, Syed Khaja Sohaebuddin

Bioengineering Theses - Archive

Recent advances in nanotechnology have lead to synthesis of high-quality nanoparticles which exhibit unique physical and chemical properties. The novel properties of these nanoparticles are widely being applied for diagnostic and therapeutic purposes and enable new means of biosensing and targeted drug delivery. However, increasing evidence has suggested that some nanoparticles may cause detrimental effects on cells and tissues. Using titanium oxide (TiO2) nanoparticles (5-10 nm diameter), silicon oxide (SiO2) nanoparticles (30 nm diameter), and multi-walled carbon nanotubes (MWCNTs) of different diameters (<8 nm, 20-30 nm, >50 nm), 0.5-2 µm in length as test subjects, we evaluated the in vitro interaction of these …

Integration Of Hyperspectral Imaging System For Optimized Data Acquisition And Control To Revolutionized Pathology Applications, Dipen Rana

Bioengineering Theses - Archive

Detecting and measuring the interactions and expression levels of tumor markers in a cancerous cell are quintessential in prognosis and management of cancer. These have propagated the need to develop better microscopic imaging techniques to understand the cellular structure and its functional behavior. Pathologist use techniques such immunohistochemistry and in situ hybridization to measure and detect these tumor marker expression levels. Fluorophores are used in these techniques as fluorescent tags to identify the tumor markers. These fluorophores have unique absorption and emission spectrum, making them useful to not only identify but also quantify the concentration levels of these markers. This …

Synthesis And Characterization Of Crosslinked Urethane Doped Polyesters For Vascular Tissue Engineering, Jagannath Dey

Bioengineering Theses - Archive

Traditional crosslinked polyester elastomers are inherently weak, and the strategy of increasing crosslink density to improve their mechanical properties makes them brittle materials. Biodegradable polyurethanes, although strong and elastic, do not fare well in dynamic environments due to the onset of permanent deformation. The design and development of a soft, strong and completely elastic (100% recovery from deformation) material for tissue engineering still remains a challenge. Herein, we report the synthesis and evaluation of a new class of biodegradable elastomers, crosslinked polyurethane-doped polyesters (CUPEs), which is able to satisfy the need for soft, strong, and elastic biomaterials. Tensile strength of …

Development Of Novel Multilayered Particles For Drug Delivery And Cell Isolation Applications, Bhanuprasanth Koppolu

Bioengineering Theses - Archive

The objective of this work is to develop multilayered nanoparticles for drug delivery and cell isolation applications. These particles principally consist of three layers; biodegradable polymer, thermo sensitive polymer and magnetic materials. For drug delivery, multilayered nanoparticles (MLNP) consisting of a magnetic core and two encompassing shells made up of temperature sensitive polymer, poly (N-isopropylacrylamide) (PNIPAAm), and biodegradable polymer, poly(D, L lactide-co-glycolide) (PLGA), were developed for targeted and controlled drug delivery. The PNIPAAm layer was immobilized onto magnetic nanoparticles (MNPs) via a silane coupling agent, Vinyltrimethoxysilane (VTMS), and free radical polymerization. These particles were then encapsulated with PLGA using a …

The Effects Of Chronic Hypoxia And Substance P On The Chemosensitive Response Of Individual Nucleus Tractus Solitarius (Nts) Neurons From Adult Rats, Nicole L. Nichols

Browse all Theses and Dissertations

The chemosensitive responses of individual nucleus tractus solitarius (NTS) neurons from neonatal rats have been extensively studied, but few studies have examined the chemosensitive responses of NTS neurons from adult rats. In addition, environmental conditions have been used to mimic respiratory diseases/disorders in rats to study how the cellular responses of individual neurons change to regulate breathing during pathological conditions. Lastly, it has been shown that substance P release increases in response to hypoxia from peripheral afferents that primarily terminate in the caudal NTS. We studied the effect of chronic hypoxia (CHx) and substance P on the response to hypercapnia …

Novel Redox And Dna-Dependent Conformational Changes In Human Ku, A Dna-Double Strand Break Repair Protein, Jason Alexander Lehman

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Ionizing radiation (IR) and radiomimetic drugs used in cancer chemotherapy cause DNA double-strand breaks which are repaired by the nonhomologous end joining (NHEJ) pathway. Ku is a heterodimeric protein comprised of 70 and 80 kDa subunits and recognizes free DNA ends. Once Ku is bound to DNA, it binds to the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and forms a heterotrimeric DNA-PK complex for repair and damage signaling.

We have analyzed the Ku protein using multiple biochemical techniques and uncovered a novel reversible redox change (Andrews, Lehman and Turchi, (2006) JBC 281(19):13596-603). From this data, we hypothesized that a redox-dependent …

Performance Analysis Of Quantitative Bone Measurement With Spiral, Multi-Detector Ct Scanners, Shruti Gupta

Browse all Theses and Dissertations

The measure of bone strength and fracture risk assessment is based primarily on bone mineral density (BMD). Computed tomography (CT), a frequently used radiographic technique that provides cross-sectional images, can be used for BMD quantification. Called quantitative computed tomography (QCT), it determines true volumetric density and also differentiates between trabecular and cortical bone. As a result, QCT improves the ability to detect early changes in trabecular BMD accurately and precisely.

The introduction of helical CT for quantitative analysis introduces new complexities. Even though using multi-detector helical CT for BMD assessment is being suggested, a detailed analysis of its validity is …