Biomedical Engineering and Bioengineering Commons^™

Connectivity Analysis Of Electroencephalograms In Epilepsy, Panuwat Janwattanapong

FIU Electronic Theses and Dissertations

This dissertation introduces a novel approach at gauging patterns of informa- tion flow using brain connectivity analysis and partial directed coherence (PDC) in epilepsy. The main objective of this dissertation is to assess the key characteristics that delineate neural activities obtained from patients with epilepsy, considering both focal and generalized seizures. The use of PDC analysis is noteworthy as it es- timates the intensity and direction of propagation from neural activities generated in the cerebral cortex, and it ascertains the coefficients as weighted measures in formulating the multivariate autoregressive model (MVAR). The PDC is used here as a feature extraction …

Multivariate Analysis For The Quantification Of Transdermal Volatile Organic Compounds In Humans By Proton Exchange Membrane Fuel Cell System, Ahmed Hasnain Jalal

FIU Electronic Theses and Dissertations

In this research, a proton exchange membrane fuel cell (PEMFC) sensor was investigated for specific detection of volatile organic compounds (VOCs) for point-of-care (POC) diagnosis of the physiological conditions of humans. A PEMFC is an electrochemical transducer that converts chemical energy into electrical energy. A Redox reaction takes place at its electrodes whereas the volatile biomolecules (e.g. ethanol) are oxidized at the anode and ambient oxygen is reduced at the cathode. The compounds which were the focus of this investigation were ethanol (C₂H₅OH) and isoflurane (C₃H₂ClF₅O), but theoretically, the sensor …

Brain Connectivity Networks For The Study Of Nonlinear Dynamics And Phase Synchrony In Epilepsy, Hoda Rajaei

FIU Electronic Theses and Dissertations

Assessing complex brain activity as a function of the type of epilepsy and in the context of the 3D source of seizure onset remains a critical and challenging endeavor. In this dissertation, we tried to extract the attributes of the epileptic brain by looking at the modular interactions from scalp electroencephalography (EEG). A classification algorithm is proposed for the connectivity-based separation of interictal epileptic EEG from normal. Connectivity patterns of interictal epileptic discharges were investigated in different types of epilepsy, and the relation between patterns and the epileptogenic zone are also explored in focal epilepsy.

A nonlinear recurrence-based method is …

The Oscillatory Shear Index: Quantifications For Valve Tissue Engineering And A Novel Interpretation For Calcification, Alex Williams

FIU Electronic Theses and Dissertations

Heart valve tissue engineering (HVTE) stands as a potential intervention that could reduce the prevalence of congenital heart valve disease in juvenile patients. Prior studies in our laboratory have utilized mechanobiological testing to quantify the forces involved in the development of heart valve tissue, utilizing a Flow-Stretch-Flexure (FSF) bioreactor to condition bone marrow stem cells (BMSCs)-derived valve tissue. Simulations have demonstrated that certain sets of flow conditions can introduce specific levels of oscillatory shear stress (OSS)-induced stimuli, augmenting the growth of engineered valves as well as influencing collagen formation, extracellular matrix (ECM) composition and gene expression. The computational findings discussed …

Quantitative Yttrium-90 Bremsstrahlung Spect/Ct And Pet/Ct Study For 3d Dosimetry In Radiomicrosphere Therapy, Senait Aknaw Debebe

FIU Electronic Theses and Dissertations

Liver cancer ranks the third most common cause of cancer related mortality worldwide. Radiomicrosphere therapy (RMT), a form of radiation therapy, involves administration of Yttrium-90 (90Y) microspheres to the liver via the hepatic artery. 90Y microspheres bremsstrahlung SPECT/CT or PET/CT imaging could potentially identify an extrahepatic uptake. An early detection of such an uptake, thus, could initiate preventative measures early on. However, the quantitative accuracy of bremsstrahlung SPECT/CT images is limited by the wide and continuous energy spectrum of 90Y bremsstrahlung photons. 90Y PET/CT imaging is also possible but limited by the extremely small internal pair production decay. These limitation …

Hydrodynamic Assessment Of A Porcine Small Intestinal Sub-Mucosa Bioscaffold Valve For Pediatric Mitral Valve Replacement, Omkar V. Mankame

FIU Electronic Theses and Dissertations

Valve replacement for critical heart valve diseases is in many cases not an option. Our clinical experience in pediatric compassionate care has shown robust function of porcine small intestinal submucosa (PSIS) valves. We assessed functional effectiveness of 4ply (~320µm) and 2ply (~166µm) PSIS mitral valves under pediatric-relevant hemodynamic pulsatile conditions. Key conclusions: (i)PSIS valves demonstrated statistically similar acute functionality in comparison to a commercially available valve. (ii)Energy losses were similar (p>0.05) under pediatric conditions which was not the case under adult aortic conditions. (iii)2ply valves were observed to be superior to 4ply, based on the robust hydrodynamic data, the …

Thermally-Assisted Acoustofluidic Separation For Bioanalytical Applications, Ata Dolatmoradi

FIU Electronic Theses and Dissertations

Changes in the biomechanical properties of cells accompanying the development of various pathological conditions have been increasingly reported as biomarkers for various diseases and as a predictor of disease progression stages. For instance, cancer cells have been found to be less stiff compared to their healthy counterparts due to the proteomic and lipidomic dysregulations conferred by the underlying pathology. The separation and selective recovery of cells or extracellular vesicles secreted from such cells that have undergone these changes have been suggested to be of diagnostic and prognostic value.

This dissertation first describes the implementation of a stiffness-based separation of phosphatidylcholine-based …

The Effect Of Hyperthermia On Doxorubicin Therapy And Nanoparticle Penetration In Multicellular Ovarian Cancer Spheroids, Abhignyan Nagesetti

FIU Electronic Theses and Dissertations

The efficient treatment of cancer with chemotherapy is challenged by the limited penetration of drugs into the tumor. Nanoparticles (10 – 100 nanometers) have emerged as a logical choice to specifically deliver chemotherapeutics to tumors, however, their transport into the tumor is also impeded owing to their bigger size compared to free drug moieties. Currently, monolayer cell cultures, as models for drug testing, cannot recapitulate the structural and functional complexity of in-vivo tumors. Furthermore, strategies to improve drug distribution in tumor tissues are also required. In this study, we hypothesized that hyperthermia (43°C) will improve the distribution of silica nanoparticles …

Optical Coherence Photoacoustic Microscopy (Oc-Pam) For Multimodal Imaging, Xiaojing Liu

FIU Electronic Theses and Dissertations

Optical coherence tomography (OCT) and Photoacoustic microscopy (PAM) are two noninvasive, high-resolution, three-dimensional, biomedical imaging modalities based on different contrast mechanisms. OCT detects the light backscattered from a biological sample either in the time or spectral domain using an interferometer to form an image. PAM is sensitive to optical absorption by detecting the light-induced acoustic waves to form an image. Due to their complementary contrast mechanisms, OCT and PAM are suitable for being combined to achieve multimodal imaging.

In this dissertation, an optical coherence photoacoustic microscopy (OC-PAM) system was developed for in vivo multimodal retinal imaging with a pulsed broadband …

Eeg Spectral Changes Before And After An Eight-Week Intervention Period Of Preksha Meditation, Chintan Joshi

FIU Electronic Theses and Dissertations

Various types of meditation techniques, primarily categorized into concentrative and mindfulness meditation, have evolved over the years to enhance the physiological and psychological well-being of people in all walks of life. However, the scientific knowledge of the impact of meditation on physiological and psychological well-being is very limited. Electroencephalography (EEG) was used to study the effect of a sequence of different forms of Preksha meditation on brain activity. EEG data from 13 novice participants (10 females, 3 males; Age: 19-49 yrs) were collected while meditating for the first time (pre) and at the end of an eight week (post) intervention …

A Biologically Plausible Supervised Learning Method For Spiking Neurons With Real-World Applications, Lilin Guo

FIU Electronic Theses and Dissertations

Learning is central to infusing intelligence to any biologically inspired system. This study introduces a novel Cross-Correlated Delay Shift (CCDS) learning method for spiking neurons with the ability to learn and reproduce arbitrary spike patterns in a supervised fashion with applicability tospatiotemporalinformation encoded at the precise timing of spikes. By integrating the cross-correlated term,axonaland synapse delays, the CCDS rule is proven to be both biologically plausible and computationally efficient. The proposed learning algorithm is evaluated in terms of reliability, adaptive learning performance, generality to different neuron models, learning in the presence of noise, effects of its learning parameters and classification …

Nanofabrication And Spectroscopy Of Magnetic Nanostructures Using A Focused Ion Beam, Ali Hadjikhani

FIU Electronic Theses and Dissertations

This research used a focused ion beam in order to fabricate record small nano-magnetic structures, investigate the properties of magnetic materials in the rarely studied range of nanometer size, and exploit their extraordinary characteristics in medicine and nano-electronics. This study consists of two parts: (i) Fabrication and study of record small magnetic tunnel junctions (ii) Introduction of a novel method for detection of magnetoelectric nanoparticles (MENs) in the tissue.

A key challenge in further scaling of CMOS devices is being able to perform non-volatile logic with near zero power consumption. Sub-10-nm nanomagnetic spin transfer torque (STT) magnetic tunneling junctions (MTJs) …

The Development Of A Novel Polymer Based System For Gene Delivery, Anh Van Le

FIU Electronic Theses and Dissertations

Gene therapy involves the use of nucleic acids, either DNA or RNA for the treatment, cure, or prevention of human diseases. Synthetic cationic polymers are promising as a tool for gene delivery because of their high level of design flexibility for biomaterial construction and are capable of binding and condensing DNA through electrostatic interactions.

Our lab has developed a novel polymer (poly (polyethylene glycol-dodecanoate) (PEGD), a polyester of polyethylene glycol (PEG) and dodecanedioic acid (DDA). PEGD is a linear viscous polymer that self-assembles into a vesicle upon immersion in an aqueous solution. A copolymer of dodecanedioc acid and polyethylene glycol …

Cobalt Ferrite Nanoparticles Fabricated Via Co-Precipitation In Air: Overview Of Size Control And Magnetic Properties, Dennis Toledo

FIU Electronic Theses and Dissertations

Cobalt Ferrite has important, size-dependent magnetic properties. Consequently, an overview of particle size is important. Co-precipitation in air was the fabrication method used because it is comparatively simple and safe. The effects of three different reaction times including 1, 2, 3 hour(s) on particle size were compared. Also, the effectiveness of three different capping agents (Oleic Acid, Polyvinylpyrollidone (PVP), and Trisodium Citrate) in reducing aggregation and correspondingly particle size were examined. Using Welch’s analysis of variance (ANOVA) and the relevant post hoc tests, there was no significant difference (p=0.05) between reaction times of 1 hour and 2 hours, but there …

Enhanced Flexible Materials For Valve Prosthesis Applications, Makensley Lordeus

FIU Electronic Theses and Dissertations

While mechanical, homograft and bio-prosthetic valves have been used in patients for many decades and have made significant improvements in patient morbidity, there is still a distinct need to overcome their limitations. Recently, emerging elastomer heart valves have been shown to be able to better re-create the flow physics of native heart valves, resulting in preferable hemodynamic responses. Unfortunately, elastomers such as silicone are prone to structural failure, which drastically limits their applicability towards the development of valve prosthesis. In order to produce a mechanically more robust silicone substrate, we reinforced it with graphene nanoplatelets (GNPs). Cytotoxicity and hemocompatibility tests …

Histological Characterization Of Inter Ictal Epileptiform Discharges Generating Brain Regions Using A Preclinical Model Of Focal Cortical Dysplasia, Abhay S. Deshmukh

FIU Electronic Theses and Dissertations

Current clinical practice of resective surgery in focal epilepsy involves electroencephalogram (EEG) brain source imaging to localize irritative brain areas from where Inter-ictal epileptiform discharges (IEDs) emerge, useful to localize the seizures-onset zones. Unfortunately, there are no previous systematic studies to characterize the pathophysiological mechanisms and abnormal cellular substrates in these irritative areas since histological data are available only from the final resective zones. To address this issue we applied a combination of EEG brain imaging described by Bae et al. (2015) using cutting-edge technology for high-density scalp EEG in rodents and histological analysis on a chronic rat model of …

Cellular Events Under Flow States Pertinent To Heart Valve Function, Glenda L. Castellanos

FIU Electronic Theses and Dissertations

Heart valve disease (HVD) or a damaged valve can severely compromise the heart's ability to pump efficiently. Balloon valvuloplasty is preferred on neonates with aortic valve stenosis. Even though this procedure decreases the gradient pressure across the aortic valve, restenosis is observed soon after balloon intervention. Tissue engineering heart valves (TEHV), using bone marrow stem cells (BMSCs) and biodegradable scaffolds, have been investigated as an alternative to current non-viable prosthesis. By observing the changes in hemodynamics following balloon aortic valvuloplasty, we could uncover a potential cause for rapid restenosis after balloon intervention. Subsequently, a tissue engineering treatment strategy based on …

Label-Free Surface-Enhanced Raman Spectroscopy-Linked Immunosensor Assay (Slisa) For Environmental Surveillance, Vinay Bhardwaj

FIU Electronic Theses and Dissertations

The contamination of the environment, accidental or intentional, in particular with chemical toxins such as industrial chemicals and chemical warfare agents has increased public fear. There is a critical requirement for the continuous detection of toxins present at very low levels in the environment. Indeed, some ultra-sensitive analytical techniques already exist, for example chromatography and mass spectroscopy, which are approved by the US Environmental Protection Agency for the detection of toxins. However, these techniques are limited to the detection of known toxins. Cellular expression of genomic and proteomic biomarkers in response to toxins allows monitoring of known as well as …

Multifunctional Nanoparticles For Theranostic Applications, Supriya Srinivasan

FIU Electronic Theses and Dissertations

Multifunctional agents for the management of highly heterogeneous diseases, like cancer, are gaining increased interest with the intent of improving the diagnostics and therapy of cancer patients. These agents are also important because more than one treatment modality is typically used for cancer therapy in the clinic. Further, nanotechnology offers a platform where more than one agent can be combined to help provide improved cancer diagnosis and therapy. Near-infrared light-activatable phototherapeutic agents have great potential in vivo. Body tissues have minimum absorption in the near- infrared range. They also have been shown to enhance the cytotoxic effect of chemotherapeutic …

Intraoperative Guidance For Pediatric Brain Surgery Based On Optical Techniques, Yinchen Song

FIU Electronic Theses and Dissertations

For most of the patients with brain tumors and/or epilepsy, surgical resection of brain lesions, when applicable, remains one of the optimal treatment options. The success of the surgery hinges on accurate demarcation of neoplastic and epileptogenic brain tissue. The primary goal of this PhD dissertation is to demonstrate the feasibility of using various optical techniques in conjunction with sophisticated signal processing algorithms to differentiate brain tumor and epileptogenic cortex from normal brain tissue intraoperatively.

In this dissertation, a new tissue differentiation algorithm was developed to detect brain tumors in vivo using a probe-based diffuse reflectance spectroscopy system. The system …

The Microstructure And The Electrochemical Behavior Of Cobalt Chromium Molybdenum Alloys From Retrieved Hip Implants, Christopher P. Emerson

FIU Electronic Theses and Dissertations

Because of their excellent mechanical, tribological, and electrochemical properties, Cobalt Chromium Molybdenum alloys have been used as the material for both the stem and head of modular hip implants. Corrosion is one mechanism by which metal debris, from these implants, is generated, which can lead to adverse events that requires revision surgery. Manufacturing process such as wrought, as-cast, and powder metallurgy influences the microstructure, material properties, and performance of these implants

The current research focuses on analyzing the microstructure of CoCrMo alloys from retrieved hip implants with optical and scanning electron microscopy. Additionally, energy disperse spectroscopy was utilized to determine …

Development Of Point-Of-Care Testing Sensors For Biomarker Detection, Xuena Zhu

FIU Electronic Theses and Dissertations

Point-of-care testing (POCT) is defined as medical testing at or near the site of patient care and has become a critical component of the diagnostic industry. POCT has many advantages over tests in centralized laboratories including small reagent volumes, small size, rapid turnaround time, cost-effectiveness, low power consumption and functional integration of multiple devices. Paper-based POCT sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for clinical diagnosis.

The focus of this dissertation was to develop simple, rapid and low cost paper-based POCT sensors with high sensitivity and portability for disease biomarker detection. Lateral …

In-Vivo Corrosion And Fretting Of Modular Ti-6al-4v/Co-Cr-Mo Hip Prostheses: The Influence Of Microstructure And Design Parameters, Jose Luis Gonzalez Jr

FIU Electronic Theses and Dissertations

The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown …

Fiber Scaffolds Of Poly (Glycerol-Dodecanedioate) And Its Derivative Via Electrospinning For Neural Tissue Engineering, Xizi Dai

FIU Electronic Theses and Dissertations

Peripheral nerves have demonstrated the ability to bridge gaps of up to 6 mm. Peripheral Nerve System injury sites beyond this range need autograft or allograft surgery. Central Nerve System cells do not allow spontaneous regeneration due to the intrinsic environmental inhibition. Although stem cell therapy seems to be a promising approach towards nerve repair, it is essential to use the distinct three-dimensional architecture of a cell scaffold with proper biomolecule embedding in order to ensure that the local environment can be controlled well enough for growth and survival. Many approaches have been developed for the fabrication of 3D scaffolds, …

Regulation Of Bone Marrow Stem Cells Through Oscillatory Shear Stresses - A Heart Valve Tissue Engineering Perspective, Sasmita Rath

FIU Electronic Theses and Dissertations

Heart valve disease occurs in adults as well as in pediatric population due to age-related changes, rheumatic fever, infection or congenital condition. Current treatment options are limited to mechanical heart valve (MHV) or bio-prosthetic heart valve (BHV) replacements. Lifelong anti-coagulant medication in case of MHV and calcification, durability in case of BHV are major setbacks for both treatments. Lack of somatic growth of these implants require multiple surgical interventions in case of pediatric patients. Advent of stem cell research and regenerative therapy propose an alternative and potential tissue engineered heart valves (TEHV) treatment approach to treat this life threatening condition. …

Theoretical Investigation Of Intra- And Inter-Cellular Spatiotemporal Calcium Patterns In Microcirculation, Jaimit B. Parikh

FIU Electronic Theses and Dissertations

Microcirculatory vessels are lined by endothelial cells (ECs) which are surrounded by a single or multiple layer of smooth muscle cells (SMCs). Spontaneous and agonist induced spatiotemporal calcium (Ca²⁺) events are generated in ECs and SMCs, and regulated by complex bi-directional signaling between the two layers which ultimately determines the vessel tone. The contractile state of microcirculatory vessels is an important factor in the determination of vascular resistance, blood flow and blood pressure. This dissertation presents theoretical insights into some of the important and currently unresolved phenomena in microvascular tone regulation. Compartmental and continuum models of isolated EC …

Development Of A Lab-On-A-Chip Device For Rapid Nanotoxicity Assessment In Vitro, Pratikkumar Shah

FIU Electronic Theses and Dissertations

Increasing useof nanomaterials in consumer products and biomedical applications creates the possibilities of intentional/unintentional exposure to humans and the environment. Beyond the physiological limit, the nanomaterialexposure to humans can induce toxicity. It is difficult to define toxicity of nanoparticles on humans as it varies by nanomaterialcomposition, size, surface properties and the target organ/cell line. Traditional tests for nanomaterialtoxicity assessment are mostly based on bulk-colorimetric assays. In many studies, nanomaterials have found to interfere with assay-dye to produce false results and usually require several hours or days to collect results. Therefore, there is a clear need for alternative tools that can …

Movement Effects On The Flow Physics And Nutrient Delivery In Engineered Valvular Tissues, Manuel Salinas

FIU Electronic Theses and Dissertations

Mechanical conditioning has been shown to promote tissue formation in a wide variety of tissue engineering efforts. However the underlying mechanisms by which external mechanical stimuli regulate cells and tissues are not known. This is particularly relevant in the area of heart valve tissue engineering (HVTE) owing to the intense hemodynamic environments that surround native valves. Some studies suggest that oscillatory shear stress (OSS) caused by steady flow and scaffold flexure play a critical role in engineered tissue formation derived from bone marrow derived stem cells (BMSCs). In addition, scaffold flexure may enhance nutrient (e.g. oxygen, glucose) transport. In this …

Neuromuscular Changes In Older Adults During The Lateral Step Task, Tatiana Bejarano

FIU Electronic Theses and Dissertations

Older adults may have trouble when performing activities of daily living due to decrease in physical strength and degradation of neuromotor and musculoskeletal function. Motor activation patterns during Lateral Step Down and Step Up from 4-inch and 8-inch step heights was assessed in younger (n=8, 24.4 years) and older adults (n=8, 58.9 years) using joint angle kinematics and electromyography of lower extremity muscles. Ground reaction forces were used to ascertain the loading, stabilization and unloading phases of the tasks. Older adults had an altered muscle activation sequence and significantly longer muscle bursts during loading for the tibialis anterior, gastrocnemius, vastus …

Optimization Of Cooling Protocols For Hearts Destined For Transplantation, Abas Abdoli

FIU Electronic Theses and Dissertations

Design and analysis of conceptually different cooling systems for the human heart preservation are numerically investigated. A heart cooling container with required connections was designed for a normal size human heart. A three-dimensional, high resolution human heart geometric model obtained from CT-angio data was used for simulations. Nine different cooling designs are introduced in this research. The first cooling design (Case 1) used a cooling gelatin only outside of the heart. In the second cooling design (Case 2), the internal parts of the heart were cooled via pumping a cooling liquid inside both the heart’s pulmonary and systemic circulation systems. …