Electronic Theses and Dissertations (2010 - Present)
Permanent URI for this communityhttps://hdl.handle.net/10657/1
The University of Houston Libraries collect and make publicly available all electronic theses and dissertations (ETDs) produced in UH graduate and PhD programs through the UH institutional repository. ETDs become available after the student submits them to the UH Graduate School, the document is approved by all appropriate parties, and any embargo on the document expires.
Collection Scope
UH Libraries began publishing ETDs from several UH Colleges in 2010. As of Summer 2014, all UH Colleges that require a thesis or dissertation for graduation began submitting these documents in electronic format. Below is a list of UH Colleges that currently participate in the ETD program and their coverage dates in this repository.
UH College | Coverage Dates |
---|---|
C.T. Bauer College of Business | 2010-Present |
Cullen College of Engineering | 2012-Present |
Conrad N. Hilton College of Hotel and Restaurant Management | 2015-Present |
College of Education | 2010-Present |
College of Liberal Arts and Social Sciences | 2012-Present |
College of Natural Sciences and Mathematics | 2012-Present |
College of Optometry | 2010-Present |
College of Pharmacy | 2010-Present |
College of Technology | 2012-Present |
K. G. McGovern College of the Arts | 2016-Present |
G. D. Hines College of Architecture & Design | 2016-Present |
Graduate College of Social Work | 2012-Present |
Additional Information
- Online access for content outside these coverage dates may be available electronically through ProQuest.
Note: As of Fall 2017, all theses and dissertations produced at UH will be submitted to ProQuest. Additionally, some UH Colleges have contributed content to ProQuest at different periods of time in the past. - For print theses and dissertations found outside these coverage dates, please consult UH Libraries’ catalog.
- Additional information on submitting ETDs can be found at the UH Graduate School.
Questions?
Feel free to contact us should you have any questions or comments.
Browse
Browsing Electronic Theses and Dissertations (2010 - Present) by Department "Biomedical Engineering, Department of"
- Results Per Page
- Sort Options
Item 3D Printing of Composite Organic Semiconductor Microdevices for Biosensors and Organic Bioelectronics(2022-05-12) Dadras, Omid; Abidian, Mohammad Reza; Mohan, Chandra; Majd, Sheereen; Raghunathan, Vijaykrishna; Chen, Tai-YenBioelectronic devices aim to alleviate symptoms or return function to patients suffering from neural disorders / injuries. Choice of functional material and employment of advanced fabrication techniques constitute key elements in ultimate success of these devices. As an alternative to traditional metallic platforms, organic electroactive materials have garnered tremendous attention in neural devices. Consequently, the emerging field of organic bioelectronics has sought to interface the organic-based devices with the soft and ion-dominated neural tissue. Organic semiconductor materials (OSs), i.e. conjugated polymers, have emerged as one of the ideal candidates for neural interfaces, owing to their biocompatibility, soft mechanical properties, and mixed electronic / ionic conductivity. This thesis is primarily focused on development of soft and conductive micron-scale platforms for applications in organic bioelectronics and biosensors. In the course of the projects, much attention has been devoted towards design of microelectronic devices, employing advanced fabrication techniques, and formulation of composite biomaterials based on two common OSs; poly(3,4-ethylenedioxythiophene) and polypyrrole. The theme of research projects falls into two main categories: 1. Soft and bioactive platforms for neural regeneration, and 2. 3D-printed conductive microelectronic devices for organic bioelectronics and biosensors. In the first category, we have developed a micro-patterning technique and have created various profiles of laminin gradients on surface of OS thin films, which can be potentially employed for neural regeneration. The second category deals with design, fabrication and characterization of 3D-printed microelectronic devices. First, we have explored 3D printing of soft, conductive, and bioactive microstructures via direct laser writing, also known as multi-photon polymerization lithography (MPL). We have formulated conductive photosensitive inks, and fabrication and characterization of microelectronic devices such as hybrid neural microelectrodes, bioactive microstructures and high-performance glucose biosensors have been successfully demonstrated. We also report on development of an in-house 3D printing technique for fabrication of OS microdevices based on in-situ electrochemical polymerization. Microelectronic devices, bioactive structures and glucose biosensors have been fabricated using this technique. Overall, we envision that these microelectronic devices and platforms pave the way towards development of next-generation neural interfaces for organic bioelectronics and biosensing applications.Item A Heart Artificial: Building the Foundation for the Development and Maintenance of In Vitro Tissue Mimetic Cardiovascular Models(2015-05) Hogan, Matthew Kevin; Birla, Ravi K.; Zhang, Yingchun; Wu, Tianfu; Mohan, Chandra; Souza, Glauco R.Given the prevalence of cardiovascular disorders and the distinct lack of significant repair mechanisms within cardiovascular systems, effective therapy for long-term treatment of cardiovascular degeneration remains a significant challenge. Further, the fundamental importance of such systems to all mammalian life begs the development of realistic component structures for in vitro assessment. Significant effort was expended to create in vitro models which mimicked a subset of structure and function of coordinate native components within cardiovascular systems. Towards this end, we developed a 3D-Artificial Heart Muscle (AHM) model utilizing fibrin gel and neonatal cardiac myocytes. We extracted functional metrics in order to probe the optimal protocol for generation of the tissue model. Building on the outcome of this experiment, we applied the optimal 3D-AHM model to a decellularized adult rat heart in order to re-append function to a complex acellular scaffold. The resultant bioartifical heart (BAH) model was assessed to identify the efficacy of 3D-AHM as a functional delivery mechanism and to lay a framework for heart model development. An alternative strategy for the generation of 3D heart muscle was explored through magnetic levitation of cardiovascular cells. Magnetic sensitivity was appended to cells through incubation with ferromagnetic nanoparticles. The cells were then levitated and cultured within a magnetic field to form 3D multicellular aggregates. (MCAs) We utilized a magnetized fibrin gel scaffold in order to apply non-contact, magnetic stretch conditioning to our AHM model through a novel bioreactor system. We were able to develop a highly functional 3D-AHM and extracted 4M cells as the optimal concentration for the generation of our artificial heart muscle. Application of a layer of 3D-AHM to an acellular rat heart proved the 3D-AHM an effective mechanism for delivery of a subset of function to a structure. Magnetic levitation generated hundreds of cell-dense, functional and phenotypically relevant heart muscle analogs. We have developed a completely novel system for the application of mechanical stretch conditioning to artificial heart muscle models and are working to implement more complex conditioning systems. The work presented herein surveys the generation of 3 unique cardiovascular model systems and a novel method for model conditioning.Item A Low Cost Wireless Sensor Interface for the Quantification of Tremor in Parkinson’s Disease(2016-08) Siddiqui, Hasan; Ince, Nuri F.; Omurtag, Ahmet; Zhang, Yingchun; Jimenez-Shahed, JoohiDeep brain stimulation surgery involves placing an electrode in the deep brain to suppress the motor symptoms of patients with Parkinson’s disease (PD). Currently physicians use the standard Unified Parkinson’s Disease Rating Scale to describe the tremor. This scale involves subjective anchor-based observations by the clinical expert. A wireless accelerometer system is presented that was built from off the shelf components to objectively quantify tremor scores. The system consists of a Teensy microcontroller and two accelerometers. It wirelessly transmits the readings through a Bluetooth module. The data is received by a custom C/C++ that parses and transmits the data to the Simulink environment for realtime visualization and analysis. The system is used to record data from patients with PD during and after DBS surgery. In this thesis, we describe the wireless accelerometer system in detail and study the correlation of sensor readings with UPDRS scores in the different DBS states. In particular, we provide data showing that such a system can be used for the objective quantification of tremor symptoms in PD patients.Item Ablation of Retbindin, the Riboflavin Binding Protein, Exacerbates Retinal Degenerative Phenotypes in Mouse Models of Human Retinal Diseases(2020-05) Genc, Ayse Mine; Naash, Muna I.; Al-Ubaidi, Muayyad R.; Conley, Shannon M.; Frishman, Laura J.; Roh, JinsookRetbindin (Rtbdn) is a retina-specific, riboflavin binding protein, expressed only by the rod photoreceptor cells. Riboflavin is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) which are essential co-factors for enzymes involved in wide-range of metabolic processes. Since flavins are directly linked to the metabolism and metabolic dysregulation is a hallmark of degeneration, we hypothesized that Rtbdn, as a riboflavin binding protein, plays a role in modulating the degenerative process. In support of our hypothesis, we found that Rtbdn is significantly upregulated in the retinas of mouse models of late-onset cone rod dystrophy (Prph2R172W), retinitis pigmentosa (RhoP23H/+) and pattern dystrophy (Prph2Y141C/+). We investigated the effect of Rtbdn ablation in these retinal degenerative models in order to elucidate the function of this novel protein in retinal health and disease. Although, the ablation of Rtbdn alone (Rtbdn-/-) had no deleterious effects on retinal function up to postnatal day (P) 120, eliminating Rtbdn in the models led to significant reductions in both scotopic and photopic electroretinographic amplitudes, compared to the single mutants. Histologic assessments revealed severe thinning of diseased retinas upon elimination of Rtbdn. While the outer nuclear layer (ONL) cell counts in wild type (WT) and Rtbdn-/- were not significantly different from each other, we observed significant loss of ONL cells in the Prph2R172W/Rtbdn-/-, RhoP23H/+/Rtbdn-/-, and Prph2Y141C/+/Rtbdn-/- in comparison to the single mutants. Ultrastructural analyses revealed shorter, malformed and disorganized photoreceptor outer segments, swollen inner segments and dilated Bruch’s membrane in the retinas of degenerative models in absence of Rtbdn. In addition, elimination of Rtbdn in the diseased retina led to vascular pathologies and appearance of neovascular tufts secondary to cell loss. We observed model-dependent alterations in the riboflavin, FAD, and FMN levels. Our data demonstrate the potential protective role of Rtbdn, making it a strong candidate as a therapeutic target in retinal degenerative diseases. Our future work will focus on investigating that potential by studying the effects of overexpression of Rtbdn in slowing the retinal degenerative process in models of human retinal degeneration.Item Acoustic Detection of Coronary Artery Occlusions Before and After Stent Placement Using an Electronic Stethoscope(2014-08) Post, Allison; Akay, Metin; Akay, Yasemin M.; Dragomir, Andrei; Bozkurt, BiykemMore than 380,000 Americans die every year from coronary artery disease (CAD). Early detection and treatment are crucial to reducing this number. Current diagnostic methods are invasive, costly, and time-consuming. Using an electronic stethoscope and spectral analysis of the recorded heart sound, we investigated the acoustic signature of CAD in subjects with only a single coronary occlusion before and after stent placement as well as subjects with clinically normal coronary arteries. The power ratio of the total power above 150Hz over the total power below 150Hz of the FFT of the acoustic signal was used to evaluate the effectiveness of stent placement. The groups were identified with this method with an 82% sensitivity and specificity. Power ratios after stent placement are not statistically different than those estimated from subjects with no coronary occlusions. Our approach demonstrates that the effectiveness of stent placement can be monitored using an electronic stethoscope.Item Adaptive Detection of Beta Bursts of Local Field Potentials Recorded from Subthalamic Nucleus in Patients with Parkinson’s Disease(2020-08) Velasco, Stephanie; Ince, Nuri F.; Zhang, Yingchun; Viswanathan, AshwinParkinson's Disease (PD) affects 1% of the world population, with this number expected to increase within the following years. Local field potentials (LFPs) recorded from deep brain stimulation (DBS) leads placed into the motor territory of the subthalamic nucleus (STN) can be used to investigate the mechanism of PD and allows for further development of new therapeutic strategies. Beta band activity, which typically presents itself as bursts, has been continuously found in the LFP recordings of PD patients. These oscillations of neural activity have been shown to correlate with motor impairment and can be suppressed by dopaminergic medication and stimulation of the brain. A novel adaptive technique we developed uses local cosine packets to detect beta bursts in LFPs and segments the data appropriately using nondyadic segmentation. We show that the spectral entropy of these adaptively captured bursts previse patient symptoms accurately and may outperform the basic beta suppression approach, such as thresholding. In this work, 120s of LFP data recorded in the resting state from chronic DBS leads of nine PD patients were segmented adaptively by entropy minimization. Using the recently developed algorithm, we performed the following: (i) adaptively segment STN LFP recordings into segments of 125ms or multiples of it, (ii) determine the entropy distribution of different time windows, (iii) correlate the change in entropy between unmedicated (OFF) and medicated (ON) states in different time windows with Unified Parkison's Disease Rating Scale (UPDRS) and computer-based measurements of bradykinesia. We found that as segment size increased, the difference in entropy between OFF and ON states enlarged. Based on entropy distribution, it was possible to determine whether a patient improved after the administration of medication. Similarly, the change of entropy in segments ≥375ms was highly correlated with the UPDRS and keyboard scores. These findings suggest that beta bursts can be adaptively segmented without the use of a predetermined threshold, therefore allowing for robust quantification of disease severity. This could enable future closed-loop DBS algorithms to become more efficient and effective when stimulating based on beta bursts detection.Item Altered Muscle Networks in Post-Stroke Survivors(2020-12) Houston, Michael James; Zhang, Yingchun; Roh, Jinsook; Li, XiaoyanFunctional interactions among muscles, indicated by muscle networks, reflect the effort of the central nervous system in reducing the redundancy of the musculoskeletal system in motor control. Efforts have been devoted to characterizing muscle network patterns in healthy subjects, however, alterations of muscle networks associated with stroke remain unexplored. Muscle networks were assessed for eight key upper extremity muscles in mild, moderate, and severe stroke survivors and compared to healthy controls to identify stroke linked alterations in the neural oscillatory drive to muscles. Intermuscular coherence was computed for all possible muscle connections and were further decomposed via non-negative matrix factorization (NNMF) to identify the common spectral patterns of coherence underlying the muscle networks. Results demonstrated that the number of identified muscle networks during force generation is reduced in stroke survivors compared to healthy controls, and the number decreases as the severity of stroke increases. Stroke patients also showed reduced coherence of higher frequencies, particularly in the in the alpha, beta, and gamma bands. The findings in this study could provide a new prospective for understanding the motor control recovery during post-stroke rehabilitation and inform future motor rehabilitation for post-stroke survivors.Item An in Vitro Investigation on Polymeric-Core Lipid Nano-carriers’ Transport across Biological Barriers and Use for Delivery of Cancer Therapeutics(2022-12-13) Kuo, Chung-Fan; Majd, Sheereen; Mohan, Chandra; Abidian, Mohammad Reza; Raghunathan, Vijaykrishna; Sirianni, Rachael W.Delivery of therapeutic and diagnostic compounds to specific sites in the body often faces several challenges. Among these challenges are crossing the obstacles created by biological barriers, such as the blood-brain barrier (BBB) and lymphatic endothelial layer, cell selectivity and efficient uptake, and retaining activity. In recent decades, nanoparticles (NPs) particularly those composed of biocompatible materials such as lipids and polymers have shown the ability to overcome these hurdles to some extent and have thus, become attractive candidates for delivery purposes in various medical applications. To date, several intrinsic physicochemical properties of NPs, such as size and surface charge, have proven to be critical in modulating NPs’ bio-distribution including their transport across biological barriers. Recent studies have suggested that NP bio-distribution is also affected by NP mechanical properties including rigidity. Such effect may in part be due to the impact of NP’s rigidity on crossing the above-mentioned barriers in the body. Centered around this hypothesis, the first part of this thesis investigates the influence of NPs’ rigidity on their ability to cross BBB and lymphatic endothelium in vitro. This part further examines the impact of NP rigidity on their interactions with brain tumor cells, for the first time. To this end, we first optimized an in vitro BBB trans-well model by evaluating several culture conditions individually and in combination, characterized by trans-endothelial electric resistance (TEER), tight junction protein expression, and barrier permeability. NPs with different elastic moduli were then prepared and evaluated for their transport across the optimized BBB model, using a new approach that relied on nanoparticle tracking analysis (NTA). We also assessed the uptake of these NPs by human glioblastoma U87 cells, as a model target. Next, we investigated the impact of rigidity on NPs traveling through the initial lymphatics under physiological conditions in vitro. These transport studies were conducted using an in vitro lymphatic endothelium trans-well model that we developed under either static or dynamic conditions. The influence of the particle elasticity along with the particle size was investigated. The second part of this thesis focuses on development and assessment of a nano-carrier for delivery of a potent cancer therapeutic, di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), to enable its safe and targeted delivery to cancerous cells. To this end, we applied NPs of poly(lactic-co-glycolic acid) (PLGA) modified with either lipids or PVA (polyvinyl alcohol) to encapsulate DpC and characterized the resultant NP for size, charge, stability, encapsulation efficiency and release of DpC. Finally, the cytotoxicity of these DpC-loaded NPs were studied in three different cancer cell lines of human glioblastoma (U87), breast cancer (MCF7), and colorectal cancer cells (HT29).Item Assessing Teratogen-Induced Changes in Murine Fetal Brain Vasculature Using In Utero Optical Coherence Tomography(2020-05) Raghunathan, Raksha; Larin, Kirill V.; Miranda, Rajesh C.; Gifford, Howard C.; Zhang, Yingchun; Mayerich, DavidThis dissertation reports the use of in utero optical coherence tomography to evaluate changes in vasculature in a developing murine fetal brain caused due to prenatal exposure to teratogens. Embryogenesis is a highly complex process that is extremely vulnerable to external factors. Proper visualization of embryonic development is crucial to understand the basic physiological processes and identify defects if any. This dissertation is divided into two major sections: 1) assessing teratogen induced changes in the murine fetal brain vasculature during the second trimester equivalent period (chapters 2-4) and 2) combining optical coherence tomography with Brillouin microscopy to image and evaluate changes in biomechanical properties during neural tube closure in order to study first trimester exposure to teratogens (appendix A3). The first section is further divided into the following sub-sections: 1) assessing alcohol induced changes in murine fetal brain vasculature, 2) assessing nicotine induced changes in murine fetal brain vasculature, and 3) assessing synthetic cannabinoid (SCB) induced changes in murine fetal brain vasculature. The advancement of algorithms to image and detect minute changes in vasculature are also detailed. The contributions of this work are significant to understand the effects of teratogens on development, as blood flow plays a major role in embryogenesis. Understanding the acute changes in vasculature caused within minutes of maternal exposure to a teratogen can open several new avenues to explore as blood flow drives organ development. Results from this dissertation have been published in 7 first author peer-reviewed publications.Item Assessing the Biomechanical Properties of Cornea using Optical Coherence Elastography(2016-05) Li, Jiasong; Larin, Kirill V.; Akay, Metin; Twa, Michael D.; Gifford, Howard C.; Wood, Lowell T.This dissertation reports on the development of measurement methods to assess the biomechanical properties of cornea based on low-coherence optical imaging, focusing on optical coherence elastographic techniques, to meet the growing demand for noninvasive high-resolution tissue characterization with improved diagnosis and treatment of ocular diseases. The research work was based on optical coherence tomography (OCT), a rapid, high-resolution, three-dimensional imaging modality that enables noninvasive depth-resolved imaging. The dissertation work is summarized in seven sections: 1) characterization the biomechanical properties of tissue mimicking phantoms, an ocular phantom, and mouse cornea in vivo using optical coherence elastography (OCE); 2) assessment the biomechanical properties of mouse corneas of different ages in vivo using air-pulse OCE; 3) the development of a method to spatially map the localized elasticity of the rabbit cornea in situ after partial riboflavin/UV-A corneal collagen cross-linking using OCE; 4) rapid characterization of the biomechanical properties of porcine corneas before and after UV-induced collagen cross-liking at different intraocular pressures by OCE; 5) the development of method to differentiate untreated and cross-linked porcine corneas of the same measured stiffness with OCE; 6) evaluation of the effects of Riboflavin/UV-A corneal collagen crosslinking on porcine corneal mechanical anisotropy with noncontact OCE; 7) a comparison of two non-contact methods to assess mechanical properties of tissue mimicking phantoms: optical coherence elastography and Michelson interferometric vibrometry. These techniques, methods and applications are demonstrated with the experiments performed on tissue mimicking phantoms (gelatin, agar, and silicone) and corneas (mouse, rabbit, porcine, both ex vivo, in situ, and in vivo) under different conditions (normal vs. cross-linking, various intraocular pressures, etc.). This dissertation represents the frontier and emerging research area of optical coherence elastography and is expected to contribute to the field of biomechanical assessment with research and clinical based applications.Item Assessing Tissue Biomechanical Properties with Noncontact Dynamic Optical Coherence Elastography(2018-05) Singh, Manmohan; Larin, Kirill V.; Akay, Metin; Twa, Michael D.; Gifford, Howard C.; Mayerich, DavidThis dissertation reports the development of noncontact techniques to quantify the biomechanical properties of various tissues utilizing optical coherence elastography. These techniques are critical for screening, detection, and monitoring of disease onset and progression as well as evaluating the effectiveness of various therapeutic procedures. The dissertation is divided into two major sections: 1) analyzing the localized dynamic deformation and 2) analyzing elastic wave propagation to quantify tissue biomechanical properties. Each of these sections is further divided. The localized dynamic tissue deformation analysis section has two sub-sections: a) real-time visual feedback and biomechanical assessment of dermal filler injections and b) evaluating the changes in local cardiac biomechanical properties after myocardial infarction. The elastic wave propagation analysis section has seven sub-sections: a) evaluating the changes in corneal biomechanical properties due to riboflavin/UV-A corneal collagen cross-linking, b) comparing the changes in corneal biomechanical properties induced by riboflavin/UV-A and rose-bengal/green light collagen cross-linking, c) quantifying the effects of tissue hydration on the stiffness of the cornea, d) assessing the elastic anisotropy of the cornea as a function of intraocular pressure, e) evaluating the changes in cardiac elastic anisotropy after myocardial infarction, f) development of an ultra-fast, single-shot, elastography technique, and g) development of a noncontact technique ca pable of assessing corneal geometry, eye-globe intraocular pressure, and corneal stiffness with a single instrument. Finally, the spatio-temporal properties of air-pulse induced displacement were characterized, and the repeatability and sensitivity of the OCE techniques described in this dissertation were compared to the “gold standard” of mechanical testing. The contributions of this work are crucial steps for the further development and clinical application of rapid, accurate, robust, and safe techniques capable of evaluating tissue biomechanical properties for early detection and monitoring of diseases.Item Assessment of Mental Workload by EEG+fNIRS(2017-05) Aghajani, Haleh; Omurtag, Ahmet; Francis, Joseph T.; Akay, Yasemin M.; Ince, Nuri F.; Madala, SridharDue to the high cognitive demands of modern technology on operators, recent studies have focused on quantitative assessment of mental workload (MWL) in order to enhance the performance, safety, and productivity in working environments. MWL monitoring systems have been used broadly in industry, military, and academia. Moreover, they can be very useful in healthcare as well. For instance, by the measurement of the cognitive load of the anesthetist or surgeons during laparoscopic and robot-assisted surgeries, the patient’s safety and the operation efficiency can be effectively improved. Brain activity measurements are highly capable of differentiation of mental states in comparison to other physiological measurements. We studied the capability of a Hybrid functional neuroimaging technique to quantify human MWL. We have used electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) as the imaging modalities with seventeen healthy subjects performing the letter n-back task, a standard experimental paradigm related to working memory. For simultaneous EEG+fNIRS data acquisition, we introduced a state of the art whole-head EEG+fNIRS set up in a single headpiece with 19 EEG and 19 fNIRS channels. We quantified the detection ability of MWL by a fully automated algorithm and compared the characteristics of each uni-modal system vs. Hybrid system. In addition, we obtained a systematic perspective about the effectiveness of features’ sub-types in the quantification of MWL. We also analyzed the spatiotemporal behavior of the brain during changes in the level of MWL. We found a specific temporal pattern for HbO concentration on the forehead. Moreover, we localized the spatial significance of the well-known EEG rhythms on the whole-head by means of multivariate statistical analysis. The Hybrid system had an accuracy that was significantly higher than that of either EEG or fNIRS. Our results suggest that EEG+fNIRS features combined with a classifier are capable of robustly discriminating among various levels of MWL. In addition, Hybrid system outperforms the unimodal systems for each subject, every classification problem, every number of features, and every window size. Based on our findings, EEG+fNIRS should be preferred to only EEG or fNIRS in developing passive BCIs and other applications, which need to monitor users’ MWL.Item Assessment of Tissue Biomechanical Properties Using Ultrasound Elastography and Optical Coherence Elastography(2022-05-10) Rippy, Justin Randall; Larin, Kirill V.; Aglyamov, Salavat R.; Liu, Jingfei; Wu, Tianfu; Schultz, Jerome S.; Mayerich, DavidThis dissertation reports several significant contributions that further the field of elastography as a whole. Each chapter also represents a key step toward the realization of quantitative compression elastography (QCE). First, motion estimation algorithms were analyzed in chapter 2 to determine which algorithm allowed for the most accurate measurement of motion and subsequent elastic wave speed. This is significant for the entire field of elastography, as motion estimation algorithms are used regardless of choice of imaging modality or method. Following this, ultrasound shear wave elastography and transient optical coherence elastography were compared under similar conditions in chapter 3 to determine if they gave comparable results. This analysis proves that the results obtained from both modalities are comparable and that they can be used interchangeably. While this is important for the field of elastography, i.e., measurements taken with one can and should be compared to the other, it is absolutely crucial for the development of QCE. If the two methods cannot give comparable results, it follows that techniques used to obtain quantitative information from one cannot be used in the other. Chapter 4 contains the most significant contribution, which is the development of QCE. QCE is a simple, multi-modal, quantitative elastography technique that borrows the idea of a compliant stress sensor from optical coherence elastography and improves upon it by removing the need for calibration. Because strain imaging and wave excitation can be performed without moving the transducer, ultrasound has the unique ability to essentially calibrate the sensor in place during the act of compression. Furthermore, this allows for a more accurate measurement than is typically possible when using a compliant sensor because the exact sensor conditions can be known at the time of measurement instead of assumed from uniaxial compression testing. Overall, the contributions of this work serve to increase accuracy in elastographic measurements, further multimodal elastography, and serve as the genesis of quantitative compression elastography methods in ultrasound.Item Bedside Washing of Stored Red Blood Cells: A Simple Apparatus Based on Microscale Sedimentation in Normal Gravity(2015-05) Huynh, Rose Ann A.; Shevkoplyas, Sergey S.; Mohan, Chandra; George, Alex; Wu, TianfuThe aim of this study was to develop and evaluate a simple, inexpensive bedside RBC washer with the capability to process multiple pRBC units within a short period without any alteration to current blood collection and storage practices. Washing pRBC units prior to transfusion is recommended for hypersensitive patients who have a higher susceptibility towards Allergic Transfusion Reactions (ATR) due to residual plasma proteins. Unfortunately, conventional washing is bulky, expensive and laborious, due to concentrating washed units through centrifugation. In response, we developed a bedside RBC washer that utilizes gravitational sedimentation of RBCs within a saline suspension. We evaluated its ability to concentrate washed pRBC units to a therapeutic hematocrit of 65%, but it optimally concentrated to a physiological hematocrit of 41%. Concentration was found to be dependent on initial morphology of the unit. In terms of improved quality, the gravity-driven washing system performed comparably with conventional washing.Item Bioengineering A Three-Dimensional Cardiac Left Ventricle(2015-05) Patel, Nikita M.; Birla, Ravi K.; May, Elebeoba E.; Liu, Yu; McConnell, Bradley K.; Omurtag, AhmetHypoplastic left heart syndrome (HLHS) is a congenital condition characterized by an underdeveloped left ventricle (LV). The current treatment options are surgery and/or heart transplant. Current tissue engineering strategies focus on graft models. The development of an engineered 3D cardiac LV would provide a therapeutic option to overcome current treatment limitations. A series of five models, to understand the ideal LV platform, fabricate and optimize a bioengineered open ventricle chamber and complete the chamber with a trileaflet valve, were produced in this research. Models were designed to emulate the human neonate LV geometry; molds were used to produce chitosan scaffolds. Functional models were fabricated by culturing rat neonatal primary cardiac cells on the chitosan scaffold. Chitosan was shown to be biocompatible with suitable material properties. An open chamber model was designed and optimized with respect to cellularization efficiency and function, using a novel seeding strategy and bioreactor, respectively; cellularized constructs demonstrated cardiac myocyte biopotential activity with contractions and pressure generation. Trileaflet valves were engineered and fitted into the open chamber to complete the bioengineered ventricle. The outcome of this research is the production of a complete bioengineered 3D cardiac LV.Item Bioinformatic Analysis and Validation of Novel Urinary Biomarkers for Bladder Cancer and Prostate Cancer(2022-08-09) Castillo, Jessica Ashley; Mohan, Chandra; Wu, Tianfu; Zhang, YingchunUrological cancers, including bladder cancer and prostate cancer are highly prominent cancers diagnosed both globally and in the United States alone. Bladder and prostate cancer rank among the top 10 most common cancers worldwide. Both cancers currently have assays approved by the United States Food and Drug Administration. However, they cannot be used as the sole measure of diagnosis and surveillance due to low specificity values and false positives. As a result, there is a need for better biomarkers for both bladder and prostate cancer. In this study, an aptamer-based SOMAscan screening was conducted of 1,317 unique proteins using urine samples from a bladder cancer, prostate cancer, and a urological control cohort. Analysis of the data identified both significant and significantly upregulated proteins. Multiple machine learning techniques identified highly discriminatory proteins. Functional pathway enrichment identified significant processes, functions, and pathways associated with each cancer. Regulatory molecules of each cancer were also identified. Following analysis, bladder cancer urine proteins of interest were validated by an enzyme-linked immunosorbent assay (ELISA) in two independent cohorts of differing ethnicity. In total, 21 urine proteins significantly discriminated bladder cancer from urology controls. Nine urine proteins distinguished bladder cancer stage T1-T4 from stage Ta-Tis. Novel proteins of prostate cancer were also identified for further validation through the use of data analysis and machine learning techniques. The study aims to successfully identify novel urinary biomarkers of both bladder and prostate cancer through the use of an aptamer-based SOMAscan, data analysis measures, including machine learning techniques, and ELISAs. Further validation may aid in early diagnosis, surveillance, and long-term survival of those with bladder and prostate cancer. The work done can potentially pave the way to engineering point-of-care tests for both bladder and prostate cancer.Item Biomarker Panel Array Systems for Disease Detection(2023-05-11) Tang, Chenling; Wu, Tianfu; Mohan, Chandra; Ning, Jing; Shevkoplyas, Sergey S.; Li, ZhengweiLupus nephritis (LN) is a devastating chronic kidney disease (CKD) caused by Systemic lupus erythematosus (SLE), an autoimmune disease that involves a loss of immune tolerance to endogenous materials and causes inflammatory responses and multiple organ damage. Currently, invasive renal biopsy as the gold standard diagnosis for LN may cause kidney injury, especially for multiple biopsy tests. Moreover, the histopathological morphology classification system doesn’t stratify the heterogenous nature of lupus patients. Fortunately, serum and urine biomarkers could potentially serve as a surrogate of disease activity, and a biomarker panel composed of multiple biomarkers could largely improve the diagnostic or prognostic sensitivity and specificity. By applying a LN biomarker panel on a multiplexable protein microarray platform, we aim to build a robust, highly sensitive, multiplexed, and high-throughput point-of-care system for lupus nephritis. This research covers four sections: (1) Discovery of novel circulating immune complexes (ICx) in the serum of lupus nephritis as potential biomarkers. Immunoproteomics-based discovery studies combined with Bioinformatics-assisted selection have enabled us to identify circulating immune complexes as potential biomarkers of LN. (2) Discovery of novel serum biomarkers that have diagnostic or predictive value in lupus nephritis. A novel serum biomarker VSIG4 has been discovered using proteomics and further validated as a promising novel serum biomarker of lupus nephritis and renal pathology activity. (3) Development of a Point-of-Care serum Biomarker-Panel Mini-Array (BPMA) system for the diagnosis, disease monitoring, and flare prediction of lupus nephritis; BPMA-S6 has been developed as a novel promising POC device for LN diagnosis, disease monitoring and flare prediction of LN (4) Discovery of novel urine biomarkers and biomarker-panel that have diagnostic or predictive values or disease monitoring capability for lupus nephritis. Collectively, this study has led to the discovery of novel biomarkers, the identification of a novel 6-plex biomarker panel, and the development of a novel biomarker panel detection system for autoimmune kidney disease. These findings hold great promise for the next generation of home care and community medicine.Item Biomechanical Characterization of Crystalline Lens by Optical Coherence Elastography(2021-12) Zhang, Hongqiu; Larin, Kirill V.; Aglyamov, Salavat R.; Schultz, Jerome S.; Zhang, Yingchun; Manns, FabriceThis dissertation reports on the application of optical coherence tomography (OCT) based elastography technique to assess the biomechanical properties of crystalline lens tissue noninvasively quantitatively. This work is summarized in four sections: 1) Assessing the Effects of Storage Medium on the Biomechanical Properties of Porcine Lens with Optical Coherence Elastography; 2) Optical Coherence Elastography of Cold Cataract in Porcine Lens; 3) The Mechanical Properties of Oxidative Cataract and the Potential Medical Treatment Measured by Optical Coherence Elastography; 4) Age-Related Changes in Rabbit Lens Viscoelasticity by Surface Wave Dispersion Analysis. These methods and applications are demonstrated with experiments on both tissue-mimicking phantoms (gelatin and agar) and lens (porcine and rabbit) ex vivo and in situ under different conditions (medium preservation, cold cataract, oxidative cataract, aging). This dissertation represents the frontier and emerging research area of noninvasive optical coherence elastography. It is expected to contribute to the field of quantitative biomechanical assessment with research and clinical-based applications.Item Biomechanics and Electromyography Inassessing Female Stress Urinary Incontinence(2016-12) Peng, Yun; Zhang, Yingchun; Boone, Timothy B.; Larin, Kirill V.; Ince, Nuri F.; Omurtag, AhmetIntroduction: Stress urinary incontinence (SUI), the involuntary urinary leakage associated with increases in intra-abdominal pressure, has a prevalence of 25–50% in U.S. women and the number of those who will undergo surgery will increase by half in the next forty years. SUI negatively affects the patient’s quality of life and places a great burden to the society. The functional anatomy of the continence mechanism remains vaguely understood. Hence my dissertation aims at offering a complete description of the pelvic floor muscles (PFM), the key contributor to the continence, thorough biomechanical and neurophysiological approaches. Methods: The biomechanical approach involves the development of a subject-specific finite element (FE) model of the female pelvic floor region. Subsequent computer simulations are targeted at finding the most contributive muscle to the urethral support function and evaluating current treatment strategies using a mini-sling. The neurophysiological approach involves the implementation of a novel surface electromyography (EMG) probe to acquire bioelectrical information of PFMs and the assessment of their innervations in healthy subjects and patients. Results: An FE pelvic floor model was developed which incorporates 40+ anatomical structural in the pelvis, representing the most complete model in the field. Simulation results showed that the vaginal walls, puborectalis, and pubococcygeus are the most important structures and that mid-distal post-urethral implantation represents the optimal location. Innervation zones of PFMs have been successfully identified and described for multiple PFMs. An high-density surface EMG-based motor unit number estimation approach was developed, providing a novel tool to evaluate the condition of neurologically impaired PFM. Conclusions: The combined information greatly advances our understanding of the physiology of PFM and would lay a firm foundation to novel, non-invasive, patient-specific interventional strategies in the future.Item CARBON MONOXIDE ADSORPTION ON Pt MONOLAYER ON Pd(hkl) SURFACE STUDIED BY SUBTRACTIVELY NORMALIZED INTERFACIAL FOURIER TRANSFORM INFRA-RED SPECTROSCOPY(2012-08) Slavkovic, Milan 1981-; Brankovic, Stanko R.; Akay, Metin; Chen, Ting Y.The progress of our civilization is critically dependent on the discovery of new materials and structures with better properties, novel functionality and applications. The ultra thin metal overlayers represent one class of such structures with increasing application in fuel cells. In our work, the two-dimensional Pt monolayers on Pd(hkl) were used as model system to study CO adsorption. The PtML/Pd(hkl) were obtained using surface limited red-ox replacement reaction of underpotentially deposited Cu monolayers on Pd(hkl) with, and without presence of citrate in the reaction solution. The strength of the CO adsorption on Pt monolayer was studied by subtractevily normalized interfacial fourier transform infra-red spectroscopy (SNIFTIRS). The SNIFTIRS results indicate synergistic effect of both; Pt monolayer and Pd(hkl), yielding a qualitatively new phenomenon where the bond of adsorbed CO on PtML/Pd(hkl) is weaker than the corresponding CO bond on each of the bulk metal surfaces. This result has fundamental importance when catalysts for oxygen reduction and hydrogen oxidation reactions are considered where the surface poisoning by intermediates or impurities is responsible for reduced catalyst activity.