Biomedical Engineering and Bioengineering Commons^™

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 …

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 …

Simulation Of Corn Stover And Distillers Grains Gasification With Aspen Plus, Ajay Kumar, Hossein Noureddini, Yaşar Demirel, David Jones, Milford Hanna

Yaşar Demirel Publications

A model was developed to simulate the performance of a lab‐scale gasifier and predict the flowrate and composition of product from given biomass composition and gasifier operating conditions using Aspen Plus software. Mass balance, energy balance, and minimization of Gibbs free energy during the gasification were applied to determine the product gas composition. Carbon conversion efficiency and tar content were provided to the model as inputs as these could not be predicted by the model based on minimization of Gibbs free energy. Experiments for validation of the model were performed on a lab‐scale fluidized bed gasifier using corn stover and …

Infrared Light Activated Floating Micro Stimulators For Neuro-Prosthetic Applications, Kimberlyn M. Gray

Doctoral Dissertations

The most common failures in neural stimulation implants are due to interconnect complications such as tissue response, lead migration, and lead breakages. The challenge in eliminating interconnects lies in minimizing device size to maintain spatial selectivity required in the CNS. One approach to this problem is a current generating device that can be stimulated by an external signal, such as light or sound. Here, we report the design, construction and testing of rnicrophotodiode devices that can be stimulated remotely with near-infrared (NIR) light to generate current that can be injected locally into the peripheral nervous system. The use of near-infrared …

Advances In Helical Stent Design And Fabrication: Studies Of Stent Thermal Treatment, Stent Mechanical Properties, And Stent Interactions With A Simulated Plaque-Laden Artery, Tre Raymond Welch

Bioengineering Dissertations - Archive

Advancements in processing biomaterials have lead to the development of bioresorbable PLLA drug-loaded stents with different geometric configurations. To further advance the technology, systematic studies have been carried out. This dissertation consists of six specific aims: 1) To characterize the effects of thermal annealing on the mechanical characteristics of PLLA helical stent, 2) To characterize the mechanical characteristics of a PLLA double helix stent, 3) To characterize the physical and chemical properties of PLLA films impregnated with niacin and curcumin, 4) To characterize the mechanical interaction of expanded stent and vascular wall with both model simulation and experimental studies using …

Functional Near Infrared Spectroscopy For The Assessment Of Motor Cortex Plasticity In Pediatric Subjects Affected By Cerebral Palsy, Bilal Khan

Bioengineering Theses - Archive

Functional near infrared spectroscopy (fNIRS) is widely used to monitor hemodynamic changes occurring in the cerebral cortex as a result of neuronal activation. One of the current challenges in this field is that activation-related hemodynamic signals are often eclipsed by global hemodynamic fluctuations due to cardiac pulsation, respiration and Mayer waves. In this study, we demonstrate by using a combination of principal component analysis (PCA) and adaptive filtering that the global hemodynamic modulation signals can be effectively removed from the fNIRS measuring cortical hemodynamic response. While pediatric subjects were performing a finger tapping task, we concurrently recorded cardiac pulsation and …

Spatiotemporal Measurement Of Freezing-Induced Deformation Of Engineered Tissues, Ka Yaw Teo

Bioengineering Theses - Archive

In order to cryopreserve functional engineered tissues (ETs), the microstructure of extracellular matrix (ECM) as well as the cellular viability should be maintained given that the functionality of ETs is closely related to the ECM microstructure. Since the post-thaw ECM microstructure is determined by the deformation of ETs during cryopreservation, the freezing-induced deformation of ETs was measured in the present study with a newly developed quantum dot (QD)-mediated cell image deformetry technique using dermal equivalents as a model system. The dermal equivalents were constructed by seeding QD-labeled fibroblasts in type I collagen matrices. After 24 hour incubation, the ETs were …

Development Of Microscope Stage Incubator For Long-Term Monitoring Of Neuronal Cell Culture During Axotomy, Kailash Karthikeyan

Bioengineering Theses - Archive

It is imperative to understand the patterns in regeneration of the central and peripheral nervous system after injury. This understanding would provide a fundamental cue towards molecules and other factors involved in regeneration, and how they affect the regeneration pattern after injury. In most culturing techniques currently used for neuronal culturing and observing the neuronal regeneration, it is difficult to determine the regeneration pattern (individual axonal level) though the overall regeneration is observed due to the complexity of neuronal network. Thus a model that provides isolation of individual axons and allowing us to monitor continuously upon injury has been developed. …

Controlled Vascular Cellular Growth By Microstructured Patterned Surfaces On Implantable Biodegradable Polymer Scaffold., Nitin Garg

Bioengineering Theses - Archive

The technological advances in the field of MEMS and biodegradable polymers with elastomeric properties have opened new areas of application for engineering of soft tissues such as blood vessel, heart valves, cartilage, tendon, and bladder, which exhibit elastic properties. In this thesis work, Microfabrication technology has successfully been applied to biodegradable polymer films to encourage cell growth in designated area. This work is presented with the final goal of fabricating implantable polymer scaffolds to produce small diameter blood vessels in a controlled manner spatially by using the concept of wettability and contact guidance.There are several methods to control cell growth …

Molecular Modelling Of Dna Translocation In Bio-Functionalized Nanopores With Applications In Gene Sequencing, Abhijit Ramachandran

Bioengineering Theses - Archive

The human genome project which was completed in 2003 took more than 12 years to complete at a cost of $2.7 billion. The advancement in technologies in the next five years led to the same feat being achieved in 5 months with a total cost of $1.5 million. Micro-fabrication technology has now made it possible miniaturize to micro- and nanofluidic devices for biochemical analysis. Solid-state nanopore based molecular analysis provides the potential to characterize and sequence DNA, based on the signature of the ionic current measured. A major challenge in using solid-state nanopores for DNA detection and sequencing is the …

Effects Of Cyclic Strain And Growth Factors On Vascular Smooth Muscle Cell Responses, Kytai Truong Nguyen, Hao Xu

Bioengineering Faculty Publications - Archive

Under physiological and pathological conditions, vascular smooth muscle cells (SMC) are exposed to different biochemical factors and biomechanical forces. Previous studies pertaining to SMC responses have not investigated the effects of both factors on SMCs. Thus, in our research we investigated the combined effects of growth factors like bFGF (basic fibroblast growth factor), TGF-�� (transforming growth factor ��) and PDGF (platelet-derived growth factor) along with physiological cyclic strain on SMC responses. Physiological cyclic strain (10% strain) significantly reduced SMC proliferation compared to static controls while addition of growth factors bFGF, TGF-�� or PDGF-AB had a positive influence on SMC growth …

Dlp Hyperspectral Imaging For Surgical And Clinical Utility, Robert Paul Francis

Bioengineering Theses - Archive

Surgeons want technology to help them see differences in tissue chemistry. If they know how oxygenated tissues and organs are during medical procedures, they are more able to eliminate dangerous tissues and maintain viable organs. Hyperspectral imaging non-invasively measures the optical absorbance spectrum of each pixel in a spatial field of view and, with chemometric image processing, can visualize the spatial distribution of tissue oxygenation. Current hyperspectral imaging systems are too slow to monitor real-time physiological changes in live tissue. Therefore, a novel DLP Hyperspectral Imaging (DLP HSI) system is developed for real-time, non-invasive, in-vivo imaging of tissue chemistry in …

A Novel Device For The Establishment Of An Animal Model Mimicking Spinal Deformity Surgery For Neurological Deficit Risk Mitigation, Bradley Elmer

Bioengineering Theses - Archive

Correction forces during spine deformity surgery impart significant multidirectional stress forces to the spinal cord, which in some cases result in severe damage to the spinal cord and permanent paralysis, the most feared complication. Animal models are critical for the development of neuroprotective strategies. However, those currently available are limited to contusion, transection, or unidirectional distraction injuries, which fail to replicate the multidirectional forces that occur during spine corrective surgery. In order to develop an improved model of distraction spinal cord injury we designed a device based on intervertebral grip fixation and linear actuators, capable of inducing controllable bidirectional distraction …

In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery, Dipendra Raj Gyawali

Bioengineering Theses - Archive

In situ crosslinkable elastic materials are increasingly being explored for various biomedical applications such as drug delivery and tissue engineering due to their site specific nature. The creation of an in situ crosslinkable elastomer rich in pendant chemistry has been a challenge in the field of biomaterials. Herein, we have developed two new in situ biodegradable materials: poly(octamethylene maleate citrates) (POMC) and poly(poly(ethylene glycol) maleate citrate) (PPEGMC). These materials are all low molecular weight in their pre-polymeric form, which shows their potential to be used as an injectable biomaterial. The preservation of pendant carboxylic and hydroxyl groups in these polymeric …

Development Of An Optical Spectroscopic Method To Detect Neurohemodynamic Changes Induced By Pain In Rats, Sweta Narvenkar

Bioengineering Theses - Archive

In my optical spectroscopy study, multi-channel, thin optical probes with short source-detector separation have been implemented, calibrated, and used along with a multi-channel spectrometer as a quantitative technique to observe changes in vascular hemoglobin concentration and hemoglobin oxygen saturation as well as light scattering of tissues. Each of the four needle probes used in my study consists of two bifurcated fibers; one fiber is connected to a halogen light source and the other fiber to a CCD-array spectrometer having a spectral window from 450 nm to 900 nm. Each fiber is 100 micron in diameter. As we utilized the four …

Magnitude And Variability In Emissions Savings In The Corn-Ethanol Life Cycle From Feeding Co-Products To Livestock, Virgil R. Bremer, Adam Liska, Terry J. Klopfenstein, Galen E. Erickson, Haishun Yang, Daniel T. Walters, Kenneth G. Cassman

Adam Liska Papers

Conclusions

• Co-product GHG emissions credit varied by >2-fold, from 11.5 to 28.3 gCO₂e per MJ of ethanol produced

• Co-product GHG emissions credit depend on
-types of co-products produced
-proportion fed to beef cattle vs. diary or swine
-location of corn production; the CP credit is highest in regions where GHG kg^-1grain are highest

• Depending on CP production types and feeding livestock classes, corn-ethanol net life cycle GHG intensity is 44-56 gCO₂e per MJ

• Midwest corn-ethanol reduces GHG emissions compared to gasoline by 47% on average, with co-products offsetting 23% of …