Engineering Commons^™

Position Concordant - Haptic Mouse, Ravi Rastogi

Theses and Dissertations

Haptic mice, computer mice modified to have a tactile display, have been developed to enable access to computer graphics by individuals who are blind or visually impaired. Although these haptic mice are potentially very helpful and have been frequently used by the research community, there are some fundamental problems with the mouse, limiting its acceptance. In this paper we have identified the problems and have suggested solutions using one haptic mouse, the VT Player. We found that our modified VT Player showed significant improvement both in terms of the odds of obtaining a correct responses and the time to perform …

Imaging Radiation Pneumonitis In A Rat Model Of A Radiological Terrorism Incident, Robert C. Molthen, Qingping Wu, Gary S. Krenz, Meetha Medhora, Elizabeth R. Jacobs, John E. Moulder

Biomedical Engineering Faculty Research and Publications

We have developed a rat model of single, sub-lethal thoracic irradiation. Our irradiation protocol is considered representative of exposures near the detonation site of a dirty bomb or small nuclear device. The model is being used to investigate techniques for identifying, triaging and treating possible victims. In addition to physiological markers of right ventricular hypertrophy, pulmonary vascular resistance, and arterial distensibility, we present two methods for quantifying microvascular density. We used methods including microfocal X-ray imaging to investigate changes in lung structure/function resulting from radiation exposure. Radiation pneumonitis is a complication in subjects receiving thoracic irradiation. A radiographic hallmark of …

Aptamer-Based Nano-Scale Dielectric Sensor For Protein Detection, Teena James

Theses

The specific detection and precise quantification of protein molecules play an essential role in basic discovery research as well as in clinical practice. In this research work, a novel protein detection mechanism based on nanoscale dielectric sensor functionalized with aptamer probes is developed. This work has been done in collaboration with Rational Affinity Devices LLC. The use of aptamer based detection offers several advantages over the traditional labor intensive antibody based immunosensing. In the initial phase of the work, the binding affinities of rationally designed oligomers towards a specific protein molecule (IgG) was studied and optimized under varying conditions of …

Deciphering The Biology Of Axon Stretch-Growth, Joseph R. Loverde

Theses

Traditional nerve regeneration strategies focus on growth cone-mediated growth, a form of nerve growth that occurs primarily during embryogenesis. Early axons continue to grow from the end distal to the soma, seeking targets on which to synapse. It is believed that once the axons synapse, stretch-growth takes over and is responsible for the great lengths achieved by nerves of the central and peripheral nervous systems. Recent work has demonstrated stretch-growth in vitro resulting in dramatically increased growth rates compared to the growth cone. Here, the aim was to decipher the underlying biology associated with axon stretch-growth using two approaches. First, …

Finger Walking Control Of A Two-Dimensional Walking Model Through Inverse Kinematics, Jordan Ratcliff

Theses

Those people who have spinal cord injuries (SCI) must remain in wheelchairs due to disruption of the neural signaling to their muscles. Functional electrical stimulation (FES) has proved itself to be an option for restoring some motion and some walking for the patient. Electrodes can either be placed on the skin or muscle to provide an electrical impulse that stimulates the muscles into contraction. Current systems provide buttons that use set functions for left and right steps with constant direction and size. It is desired however that the user be allowed a more natural and variable control method of controlling …

Dual Parametric Sensors For Highly Sensitive Nucleic Acid Detection, Manu Sebastian Mannoor

Theses

The primary focus of this research work was on the design and development of a molecular scale (nano-scale) capacitive sensing mechanism for the highly sensitive and label-free detection of Nucleic Acid hybridization. These novel capacitive sensors with nano-scale electrode spacing offer solutions to many problems suffered by the conventional signal transduction mechanisms, thereby immensely improving the sensitivity of the biomolecular detection processes. Reducing the separation between the capacitive electrodes to the same scale as the Debye length of the sample solution, results in the overlapping of the electrical double layers of the two electrodes, thereby confining them to occupy a …

Evaluation Of Medical Alarm Sounds, Elizbha Philip

Theses

Auditory alarms in medical equipments perform considerably below their optimal level. Concern has been expressed about the quality of medical alarms by a large number of researchers in recent years. A detailed literature survey on the medical alarm related problems has been carried out. Hospital visits were made to obtain real life information and data of alarm sounds in various type of monitors used in OR and ICU. A laboratory experiment has been conducted on selected melodic alarm sounds. These melodic alarm sounds are being implemented in medical equipments and the idea of design is proposed in ISO / IEC …

Study And Development Of Ultrasound Monitoring Of Skeletal Defects, Kavil Patel

Theses

Fatigue fractures are fine disruptions of normal bone architecture whose identification is often unreliable or difficult using x-rays (Robinson, Wilson et al.; Kundel 2004; Swischuk and Hernandez 2004). A fatigue fracture results from the application of abnormal loads to a bone with normal elastic resistance and is associated with new or different activity, and strenuous or repeated activity. The feasibility of using ultrasound to detect and monitor fatigue fractures and other structural damage in bone was established in this study.

The use of Low Transient Pulse (LTP) technology to drive the ultrasound transducers proved to enhance detection resolution and quality …

Assessing Trainer Hand Forces For Manual Body Weight Supported Walking, Manish Raval

Theses

Spinal cord injuries occur in approximately 12,000 to 15,000 people per year in the U.S. About 10,000 of these people are permanently paralyzed. Most spinal cord traumas occur in young, healthy individuals. Males between 15 and 35 years old are most commonly affected.

Recently new approaches to facilitate walking recovery for individuals after a spinal cord injury, have been directed towards a therapy known as Locomotor Training (LT) that implements repetitive stepping on a treadmill using body weight support. A major intent of LT research is to investigate the effect of an extended period of LT on bilateral muscle activation …

Comparing Stent Design Using Computational Fluid Dynamics To Predict Wall Shear Stress Based Parameters, Jonathan Murphy, Fergal Boyle

Conference Papers

No abstract provided.

Rapid-Response Urban Cfd Simulations Using A Gpu Computing Paradigm On Desktop Supercomputers, Inanc Senocak, Julien C. Thibault, Matthew Caylor

Mechanical and Biomedical Engineering Faculty Publications and Presentations

In the event of chemical or biological (CB) agent attacks or accidents, first-responders need hazard prediction data to launch effective emergency response action. Accurate and timely knowledge of the wind fields in urban areas is critically important to identify and project the extent of CB agent dispersion to determine the hazard-zone. In their 2008 report (GAO-08-180), U.S. Government Accountability Office has reported that first responders are limited in their ability to detect and model hazardous releases in urban environments. The current set of modeling tools for contaminant dispersion in urban environments rely on empirical assumptions with diagnostic equations (Wang et …

Can We Engineer Our Way To Good Health?, Russell T. Carr

The University Dialogue

No abstract provided.

Preparation And Characterization Of Protein-Nanotube Conjugates, Jonathan S. Dordick, Dhiral A. Shah, Ravindra C. Pangule, Shyam Sundhar Bale, Prashanth Asuri, Amit Joshi, Akhilesh Banerjee, David Vance, Ravi S. Kane

Bioengineering

This chapter describes methods of immobilizing proteins on carbon nanotubes, using two different routes—physical adsorption and covalent attachment. We also provide an overview on how such conjugates can be characterized with the help of various techniques, such as Raman, Fourier transform infrared (FT-IR), circular dichroism (CD), and fluorescence spectroscopies, in addition to the standard enzyme kinetic analyses of activity and stability. Both the attachment routes—covalent and noncovalent—could be used to prepare protein conjugates that retained a significant fraction of their native structure and function; furthermore, the protein conjugates were operationally stable, reusable, and functional even under harsh denaturing conditions. These …

Subject Specific Computational Models Of The Knee To Predict Anterior Cruciate Ligament Injury, Bhushan S. Borotikar

ETD Archive

Knee joint is a complex joint involving multiple interactions between cartilage, bone, muscles, ligaments, tendons and neural control. Anterior Cruciate Ligament (ACL) is one ligament in the knee joint that frequently gets injured during various sports or recreational activities. ACL injuries are common in college level and professional athletes especially in females and the injury rate is growing in epidemic proportions despite significant increase in the research focusing on neuromuscular and proprioceptive training programs. Most ACL injuries lead to surgical reconstruction followed by a lengthy rehabilitation program impacting the health and performance of the athlete. Furthermore, the athlete is still …

A Binary Method For Simple And Accurate Two-Dimensional Cursor Control From Eeg With Minimal Subject Training, Turan A. Kayagil, Ou Bai, Craig S. Henriquez, Peter Lin, Stephen J. Furlani, Sherry Vorbach, Mark Hallett

Biomedical Engineering Publications

Background

Brain-computer interfaces (BCI) use electroencephalography (EEG) to interpret user intention and control an output device accordingly. We describe a novel BCI method to use a signal from five EEG channels (comprising one primary channel with four additional channels used to calculate its Laplacian derivation) to provide two-dimensional (2-D) control of a cursor on a computer screen, with simple threshold-based binary classification of band power readings taken over pre-defined time windows during subject hand movement.

Methods

We tested the paradigm with four healthy subjects, none of whom had prior BCI experience. Each subject played a game wherein he or she …

Ultrasonic Angioplasty: Assessing The Risk Of Arterial Perforation, Mark Wylie, Garrett Mcguinness, Graham Gavin

Conference Papers

Atherosclerosis is a cardiovascular disease that effects large and medium muscular arteries (such as coronary and iliac) and also large elastic arteries (such as aorta) [1]. It causes thickening of the arterial wall and over time can result in a completely blocked artery or chronic total occlusion (CTO). While the majority of atherosclerotic lesions can be attempted by typical Percutaneous Transluminal Coronary Angioplasty (PTCA) such as balloon and stent implantation, calcified CTOs are often problematic as they do not lend themselves to be accessed by the guidewire which is required to implant the balloon and stent. Excessive guidewire pushing force …

A Computer Science Approach To Identify And Classify Hyperactivated Spermatozoa, Norbert Kaula

Electronic Theses and Dissertations

Effective Assisted Reproductive Technology (ART) relies in part upon accurate but easily conducted measurements of sperm motion parameters. Several established methods are widely used to assess possible reasons for male infertility, in human and veterinary Andrology clinics. Computer-assisted sperm analysis (CASA) devices quantitatively assess sperm motion parameters, which have been defined by the World Health Organization, and include the percentage of motile cells in a sample and the motion characteristics of individual cells, such as curvilinear velocity (VCL), average path velocity (VAP) and straight line velocity (VSL). However, CASA analyses fail to define hyperactive sperm motility or determine the prevalence …

A Model For Electrical Communication Between Cochlear Implants And The Brain, Douglas A. Miller

Electronic Theses and Dissertations

In the last thirty years, cochlear implants have become an invaluable instrument in the treatment of severe-to-profound hearing impairment. An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms intended to improve perception of speech and other auditory signals. In trying to determine how closely cochlear implant recipients process sound relative to the processing done by a normal auditory system, various assessment techniques have been applied. The most common technique has been measurement of auditory evoked potentials (AEPs), which involves the recording of neural responses to auditory stimulation. Depending …

A Computational Model Of Breast Ducts, Jordan Greenlee

Inquiry: The University of Arkansas Undergraduate Research Journal

Ductal Carcinoma represents almost 75% of breast cancer. In this specific type of cancer. malignant cells in the breast ducts invade the surrounding healthy tissue. Almost all researchers who are investigating microwave modality in the area of breast cancer detection employ oversimplified models of the internal structure of the breast. Use of engineered or biologically inaccurate models can render inaccurate results. Therefore. a mathematical biological model was implemented in this work aiming to bridge the gap between physiologists and engineers. The result show that the proposed breast duct model has the capability of modeling the breast ducts of different kinds …

Cuda Implementation Of A Navier-Stokes Solver On Multi-Gpu Desktop Platforms For Incompressible Flows, Julien C. Thibault, Inanc Senocak

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Graphics processor units (GPU) that are traditionally designed for graphics rendering have emerged as massively-parallel "co-processors" to the central processing unit (CPU). Small-footprint desktop supercomputers with hundreds of cores that can deliver teraflops peak performance at the price of conventional workstations have been realized. A computational fluid dynamics (CFD) simulation capability with rapid computational turnaround time has the potential to transform engineering analysis and design optimization procedures. We describe the implementation of a Navier-Stokes solver for incompressible fluid flow using desktop platforms equipped with multi-GPUs. Specifically, NVIDIA’s Compute Unified Device Architecture (CUDA) programming model is used to implement the discretized …

Application Of Dual-Energy Computed Tomography To The Evalution Of Coronary Atherosclerotic Plaque, Mitya M. Barreto

ETD Archive

Atherosclerotic coronary artery disease is responsible for around 50 of cardiovascular deaths in USA. Early detection and characterization of coronary artery atherosclerotic plaque could help prevent cardiac events. Computed tomography (CT) is an excellent modality for imaging calcifications and has higher spatial resolution than other common non-invasive modalities (e.g MRI), making it more suitable for coronary plaque detection. However, attenuation-based classification of non-calcified plaques as fibrous or lipid is difficult with conventional CT, which relies on a single x-ray energy. Dual-energy CT (DECT) may provide additional attenuation data for the identification and discrimination of plaque components. The purpose of this …

Development Of A Focused Broadband Ultrasonic Transducer For High Resolution Fundamental And Harmonic Intravascular Imaging, Chaitanya K. Chandrana

ETD Archive

Intravascular ultrasound (IVUS) is increasingly employed for detection and evaluation of coronary artery diseases. Tissue Harmonic Imaging provides different tissue information that could additionally be used to improve diagnostic accuracy. However, current IVUS systems, with their unfocussed transducers, may not be capable of operating in harmonic imaging mode. Thus, there is a need to develop suitable transducers and appropriate techniques to allow imaging in multi modes for complementary diagnostic information. Focused PVDF TrFE transducers were developed using MEMS (Micro-Electro-Mechanical-Systems) compatible protocols. The transducers were characterized using pulse-echo techniques and exhibited broad bandwidth (110 at -6dB) with axial resolutions of Such …

Altered Cortico-Cortical Brain Connectivity During Muscle Fatigue, Zhiguo Jiang

ETD Archive

Traditional brain activation studies using neuroimaging such as functional magnetic imaging (fMRI) have shown that muscle fatigue at submaximal intensity level is associated with increased brain activity in various cortical regions from low- to high-order motor centers. However, how these areas might interact remain unclear since previous activation studies related to motor control could not reveal information of between-area interaction. This issue can be addressed by evaluating brain activation data using the framework of connectivity analysis. Three types of brain connectivity, functional connectivity (FC), effective connectivity (EC) and structural connectivity (SC) have been examined to investigate the effect of voluntary …

Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens

ETD Archive

Novel tyramine-based hyaluronan (HA) and collagen hydrogels have been developed in which cross-linking is accomplished via peroxidase-mediated dityramine linkages allowing direct cross-linking in vivo. These TB hydrogels possess advantageous physical properties, which include excellent biocompatibility and the ability to mimic the biological, structural and mechanical properties of normal, healthy tissues, including cartilage, and thus provide for synthetic, implantable biomaterials suitable for a wide range of tissue types. The efficacy of these TB-hydrogels has been previously tested in a number of clinically relevant animal models, which have evaluated their applicability for the repair/replacement of various tissues, including cartilage. Nevertheless, there exists …

Semi-Automatic Segmentation Of Normal Female Pelvic Floor Structures From Magnetic Resonance Images, Xiaolong Li

ETD Archive

Stress urinary incontinence (SUI) and pelvic organ prolapse (POP) are important health issues affecting millions of American women. Investigation of the cause of SUI and POP requires a better understand of the anatomy of female pelvic floor. In addition, pre-surgical planning and individualized treatment plans require development of patient-specific three-dimensional or virtual reality models. The biggest challenge in building those models is to segment pelvic floor structures from magnetic resonance images because of their complex shapes, which make manual segmentation labor-intensive and inaccurate. In this dissertation, a quick and reliable semi-automatic segmentation method based on a shape model is proposed. …

Two Approaches For Cell Retention In Perfusion Culture Systems, Zhaowei Wang

ETD Archive

A lack of efficient, economical, and reliable cell retention devices has limited the application of perfusion culture systems in the biopharmaceutical industry. Two types of cell retention devices were developed in this work for long-term perfusion culture systems: a modification of an inclined gravity settler and a variation of an ultrasonic filter. Both bench-top and large-scale tests showed that the gravity settler can effectively retain viable cells and preferentially remove nonviable cells in perfusion culture systems. The viable cell retention rate can be maintained well above 90 during long-term perfusion culture period while the nonviable cell retention rate is 20-30 …

Cortical Bone Tissue Engineering;Scaffold Design And Cell Selection, Demin Wen

ETD Archive

Cortical bone tissue engineering provides a promising approach to generate graft materials needed to treat the large sized bone defects. The underling premise of tissue engineering is to mimic the in vivo microenvironment as best as possible in vitro culture system. To select an appropriate scaffold material used in this model system, mechanical and hydraulic permeability properties of 316L porous stainless steel and polymethylmethacrylate (PMMA) were studied, as well as their biocompatibility in short and long term cell culture. Results showed that scaffolds made of both stainless steel and PMMA: (1) could be manufactured to have similar permeability as that …

The Synthesis And Characterization Of Novel Elastin-Like Polypeptides Containing An Oligomerization Domain, James T. Cole

ETD Archive

Elastin like polypeptides (ELPs) are an emerging class of biomaterials due to their unique group of chemical, physical and biological properties. We have constructed a library of ELPs based on the pentapeptide amino acid repeat sequence (GVGVP). ELPs exhibit lower critical solution temperature (LCST) transition behavior from a soluble phase below the transition temperature (Tt) to an insoluble two phase system above the transition temperature. This process is completely reversible so that ELPs can become soluble again upon lowering the temperature. This temperature can be tuned in many different ways at the molecular level by changing the composition of the …

Slurry Based Coatings On Silicon Based Ceramics, Muralidhar Challarapu

ETD Archive

Silicon carbide/silicon carbide (SiC/SiC) composites are the leading candidates for advanced high temperature structural components in gas turbine engine application. When SiC surface reacts with O2, protective SiO2 scales are formed, which are the basis for the corrosion resistance of SiC. Their main draw back in terms of usage in a gas-turbine engine is the volatilization of the protective silica scale because of the water vapor which is a byproduct of fuel combustion. The purpose of this project was to develop environmental barrier coatings (EBCs) based on ceramic powders to provide resistance to such moisture damage. In this thesis slurry-coating …

Flow Measurements In Turbulent Flow Fields With Magnetic Resonance Phase Velocity Mapping, Navneeth Sagar Reddy Lakkadi

ETD Archive

Arterial stenosis (narrowing) is due to vascular disease that, if untreated, leads to death. The stenosis causes the development of complex flow which results in high energy losses and great forces between blood and tissue. Traditionally, turbulent flows lead to signal loss in magnetic resonance (MR) image acquisitions, resulting in loss of diagnostic information. With the advancement in MR hardware and software, some of the limitations of MR in turbulent flow fields may have been reduced or eliminated. This study evaluated the potential of MR phase velocity mapping (MRPVM), a clinical velocimetry technique, under turbulent flow conditions such as those …