Digital Commons Network^™

Cellular Attachment On Poly(Lactic Acid) For Use In Tissue Engineering, Stephen R. Hunter

Masters Theses

Tissue engineering is a promising new method for organ regeneration. This method can be used to repair damaged tissue, or possibly replace a fully functional organ. In summary, a biopsy is taken from a donor, isolated, then grown onto a framework resembling an organ. Once grown; it is then transplanted into the patient. Over time, the body will degrade the scaffold, leaving the organ or tissue in its place. As this scaffold is present in the body for an extended time; factors like biocompatibility, toxicity, immunogenicity, and structural stability must be researched.

Several polymers have already been researched for use …

Ac Electrokinetic Effect Of V-Electrode Pattern On Microfluids, Mohammad Salman Parvez

Theses and Dissertations

Electrokinetics has been used for guiding, pumping, and manipulating microfluidic particles for many years in the field of Biomedical, Microbiology, Chemistry, Medicine, and other fields of research, which makes it a ubiquitous tool for the multidisciplinary research on microfluidics. Between these two Alternating Current (AC) Electrokinetics have been proven to be more feasible for the researcher than the other one. In this research, we have investigated AC Electrokinetics and s effect on a new electrode configuration called V-electrode pattern. The V-electrode has been inspired and modified from the previous research work on the Orthogonal Electrode Pattern. In this research, this …

3d Printed Microporous Collagen Constructs Using The Freeze-Fresh Methodology, Thais Sousa Senzano

Theses and Dissertations

Scaffold microporosity is known to play a critical role in governing cellular response including cell migration, proliferation, and tissue-specific differentiation. While fabrication approaches such as solvent leaching and freeze-casting are commonly used for the generation of microporous biomaterial scaffolds, these methods provide little control over scaffold geometry and creation of complex tissue structures. Extrusion-based 3D printing, an additive manufacturing method, is a highly versatile layer-by-layer printing approach that allows for the fabrication of easily customizable 3D scaffolds with complex architecture using a vast selection of polymeric bioinks. These 3D printed constructs are porous at the macroscale, but achieving microporosity (i.e., < 100 μm) in printed constructs is challenging due to the sub-optimal resolution of the extrusion-based printing method. A recent study using alginate inks introduced a new fabrication technique termed Freeze-FRESH(FF)that combines extrusion printing and freeze-casting approaches to generate 3D constructs with hierarchical microporosity. However, the porosity of the resultant alginate constructs was comparable despite changing the freezing temperature. In the current study, the FF method was modified to print collagen constructs with greater control of microporous architecture. Highly concentrated collagen type I ink was used to 3D print collagen constructs using the freeform reversible embedding of suspended hydrogels (FRESH)approach. Modification of the FF technique entailed melting of the FRESH bath post printing via incubation at 37 °C followed by freezing and lyophilization to allow for collagen gelation and better heat transport during the freezing process. The effect of freezing temperature on micropore size, swelling degree, degradation, and mechanical properties of printed constructs was assessed. Finite element (FE) models were generated to predict the mechanical properties of microporous scaffolds. In addition, the effect of microporosity on Saos-2 cell morphology, proliferation, infiltration, and ALP activity was evaluated. Results from the study showed that freezing temperature effectively modulated micropore size and that constructs with larger micropore size were more stable. Microporosity had no effect on swelling ratio yet caused a decrease in mechanical properties of collagen constructs; FE models confirmed experimental results. Cell metabolic activity and infiltration was enhanced in microporous constructs with larger pore size, yet there was no effect on cell morphology, and ALP activity. In conclusion, the modified FF technique can be effectively used to fabricate hierarchically porous 3D collagen constructs.

Recombinant Piriform Spider Silk Production, Cole R. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider silks are remarkable biomaterials, possessing a variety of desirable mechanical and material properties. Humans have long-sought to utilize these materials. Spiders produce a range of different types of silks for different purposes, such as web-building, egg casing, and prey swathing. Because spiders are difficult to farm, a synthetic biological approach must be used to produce silk-like proteins. This research is intended to improve the production of piriform, a specific type of spider silk. This was done with targeted-improvements to microbial metabolism and recovery methodologies. The methods developed in this research are useful for other types of silk production and …

Laboratory Scale Anaerobic Reactors For Bioenergy From Wastes: Materials, Mathematical Models, And Stoichiometry, Yehor Pererva

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Anaerobic processes are being explored for the production of bioenergy in the form of biomethane and biohydrogen in a "waste-to-value" approach that considers wastes as a resource. Laboratory scale Biomethane potential (BMP) tests and Up-Flow Anaerobic Sludge Blanket (UASB) reactors can be used to indicate the potential recovery of bioenergy from industry wastes. The goals of this research were to: (1) conduct a critical review of models for determining biomethane potential, (2) develop a theoretical relationship for stoichiometry for biomethane and biohydrogen from wastes, and (3) develop key design aspects for geometry and infrastructure, including gas-liquid-solid separation in laboratory UASB …

Fate Of Pharmaceuticals And Personal Care Products In Duckweed And Waste Activated Sludge Under Aerobic And Anaerobic Solids Stabilization Conditions, Kwame Tweneboah Duodu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twelve commonly used pharmaceuticals and personal care products (PPCPs)(acetaminophen, β-Estradiol, caffeine, carbamazepine, DEET, estrone, gemfibrozil, triclosan, TCEP, sulfamethoxazole, progesterone, fluoxetine) were investigated to determine their fate in biosolids. These compounds were selected due to their wide usage, and varying properties, that makes them representative of many other PPCPs.

Commonly used PPCPs (caffeine commonly found in tea, coffee, chocolate and soda, the pain reliever acetaminophen, and the pesticide DEET) were detected in high amounts in the influent of the Hyrum WWTP and Wellsville sewage lagoons. Although conventional WWTPs are not designed to remove PPCPs from wastewater, some PPCPs, such as acetaminophen, …

Molecular Mechanisms And Design Of Hydrogen-Bonded Materials For Thermal Applications, Jinlong He

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heat transfer at the nanoscale plays an important role in determining the reliability and performance of many innovative advanced materials technologies such as nanoelectronics, semiconductor, biomedical devices, polymers, and composites. Extensive efforts have been made to design materials with extraordinary thermal properties. However, fundamental understanding of heat transfer in many of these materials is still not lacking, because the thermal transport processes are governed by several factors including molecular morphology and chemical bonding. Among these factors, the atomic bonding between two dissimilar materials or within single materials is of particular interest due to its ubiquity and importance in physical processes. …

Development Of Molecular Sensor And Imaging Analysis Techniques For Improving Life Quality, Wei Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As life science advances, we are getting closer and closer to understanding the truth about life. Some specific cell types or molecules play a vital role in regulating routine functions of life. The imperceptible changes of these critical components can lead to serious diseases. Traditionally, histopathological techniques are widely employed to study and diagnose human diseases. However, these methods are time consuming and invasive. Herein, we introduce multiple types of biosensors that are sensitive, easy to use and most importantly non-invasive. First, I developed a smartphone based colorimetric sensor for detection of water hardness in a convenient way by introducing …

Fast Neutron Assay Of Elemental Content Of Bulk Samples, Calder Emerson Lane

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to analyze the capabilities of fast neutrons in the detection and analysis of various isotopes in bulk samples. The deuterium-tritium (DT) fusion reaction generates highly penetrating, high-energy (14.1-MeV) neutrons which induce nuclear reactions in irradiated targets. Neutrons and gamma rays are generated in these reactions. Emitted gamma rays are characteristic of the emitter; the gamma spectrum enables stoichiometric identification of the assayed samples. Neutron backscattering can also be used for identification of the elemental composition of the sample.

This work had three objectives. The first objective was to develop a computational technique to model …

Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez

Theses and Dissertations

The goal of this thesis is to determine the efficacy of employing Machine Learning (ML) to solve Joint Urgent Operational Need (JUON) CC-0575, which aims to develop a Common Operating Picture (COP) of the Global Positioning System (GPS) Electromagnetic Interference (EMI) environment. With the growing popularity of Artificial Neural Networks (ANNs), ML solutions are quickly gaining traction in businesses, academia and government. This in turn allows for problem solutions that were previously inconceivable using the classical programming paradigm. This thesis proposes a method to develop a COP of the battlefield via ANN ingestion of multiple-source signals and sensors. We conduct …

Electro-Optic Satellite Constellation Design Using Multi-Objective Genetic Algorithm, Yasin Tamer

Theses and Dissertations

Satellite constellation design is a complex, highly constrained, and multidisciplinary problem. Unless optimization tools are used, tradeoffs must be conducted at the subsystem level resulting in feasible, but not necessarily optimal, system designs. As satellite technology advances, new methods to optimize the system objectives are developed. This study is based on the development of a representative regional remote sensing constellation design. This thesis analyses the design process of an electrooptic satellite constellation with regional coverage considerations using system-level optimization tools. A multi objective genetic algorithm method is used to optimize the constellation design by utilizing MATLAB and STK integration. Cost, …

Concentration And Treatment Of Odors Generated By Landfills, Gabriel Cohen

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Landfills produce hydrogen sulfide (H₂S), an odorous compound that can be a nuisance and danger to public. Biological treatment, in particular bio-trickling filters, is a method for controlling H₂S emissions but startup costs can be costly. The goal of this study is to provide a low-cost method for improving environmental air quality in Nebraska through an odor control device. This study determined that the Loup Central Landfill located near Elba, NE would be an adequate site for the testing and implementation of the odor control device. The off-gas of the Loup Central Landfill was tested for …

Medical Knowledge-Enriched Textual Entailment Framework, Shweta Yadav, Vishal Pallagani, Amit P. Sheth

Publications

One of the cardinal tasks in achieving robust medical question answering systems is textual entailment. The existing approaches make use of an ensemble of pre-trained language models or data augmentation, often to clock higher numbers on the validation metrics. However, two major shortcomings impede higher success in identifying entailment: (1) understanding the focus/intent of the question and (2) ability to utilize the real-world background knowledge to capture the context beyond the sentence. In this paper, we present a novel Medical Knowledge-Enriched Textual Entailment framework that allows the model to acquire a semantic and global representation of the input medical text …

Identifying Depressive Symptoms From Tweets: Figurative Language Enabled Multitask Learning Framework, Shweta Yadav, Jainish Chauhan, Joy Prakash Sain, Krishnaprasad Thirunarayan, Amit P. Sheth, Jeremiah Schumm

Publications

Existing studies on using social media for deriving mental health status of users focus on the depression detection task. However, for case management and referral to psychiatrists, healthcare workers require practical and scalable depressive disorder screening and triage system. This study aims to design and evaluate a decision support system (DSS) to reliably determine the depressive triage level by capturing fine-grained depressive symptoms expressed in user tweets through the emulation of Patient Health Questionnaire-9 (PHQ-9) that is routinely used in clinical practice. The reliable detection of depressive symptoms from tweets is challenging because the 280-character limit on tweets incentivizes the …

Experimental Analysis Of Heat Generation In Carbon, Mounisha Ganesan

Doctoral Dissertations and Master's Theses

The purpose of this research is to study a novel non-covalent functionalization technique of single-walled carbon nanotubes (SWCNTs) and to examine the feasibility of using carbon nanotube films as thin film heaters. We developed a unique methodology to synthesize a well dispersed, environmentally friendly solution of CNTs that could be easily spin coated as well as spray coated on different substrates based on the application. Using the produced solutions, thin films of SWCNTs were fabricated on a glass substrate. Two sets of experiments were conducted to study the influence of polyaromatic moiety and the pH on the electro thermal characteristics …

Parametric Analysis Of Particle Spreading With Discrete Element Method, Yuxuan Wu

Doctoral Dissertations and Master's Theses

The spreading of metallic powder on the printing platform is vital in most additive manufacturing methods, including direct laser sintering. Several processing parameters such as particle size, inter-particle friction, blade speed, and blade gap size affect the spreading process and, therefore, the final product quality. The objective of this study is to parametrically analyze the particle flow behavior and the effect of the aforementioned parameters on the spreading process using the discrete element method (DEM). To effectively address the vast parameter space within computational constraints, novel parameter sweep algorithms based on low discrepancy sequence (LDS) are utilized in conjunction with …

Numerical Analysis Of Multi-Functional Surface Acoustic Wave Sensor, Xin Xu

Doctoral Dissertations and Master's Theses

A surface acoustic wave (SAW) sensor can have broad industrial applications due to its compact size, low cost-effectiveness, and versatility of sensible measurands, as well as the wireless capabilities. In this study, a theoretical modeling approach accompanied by a MATLAB-based algorithm of the SAW device is first presented. With the designed dimensional parameters and selected material properties, numerical analyses are performed using COMSOL Multiphysics to validate the theoretical results. Various postprocessing responses of the propagated SAWs in both time and frequency domains, such as time delay, insertion loss, and frequency shift, are examined to evaluate the device performances. Also, the …

Investigation Of Electrospun Nanofibers For Separation Applications, Shu-Ting Chen

Graduate Theses and Dissertations

Electrospun membranes are an attractive alternative to flat sheet membranes as absorbent with numerous advantages like high porosity, large specific surface area and ease of functionalization. This doctoral dissertation focuses on fabricating novel polymeric membrane adsorbents for protein separations and ammonium ion removal. Three distinctly different preparation methods including UV-initiated polymerization, atom transfer radical polymerization, and mixed-matrix formation, have been employed to fabricate the electrospun membranes. Overall, this study aimed to develop electrospun membranes with excellent separation efficiency for application in protein purification and ammonium ion removal.

Chapter 2 details the stepwise development of weak anion exchange membranes and subsequent …

An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero

Graduate Theses and Dissertations

Salmonella Typhimurium is a foodborne pathogen associated with raw and undercooked eggs, poultry, beef, fruits, and vegetables. In the United States, Salmonella is responsible for approximately 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths annually. For many years, conventional detection methods such as culture-dependent and PCR-based methods have been the “golden standards” for the detection of this pathogen due to their high sensitivity and reliability. However, they still have some disadvantages such as long enrichment steps and high costs that need to be overcome. The development of a rapid and reliable method for the detection of S. Typhimurium is needed …

Multiphoton Microscopy And Deep Learning Neural Networks For The Automated Quantification Of In Vivo, Label-Free Optical Biomarkers Of Skin Wound Healing, Jake D. Jones

Graduate Theses and Dissertations

Non-healing ulcerative wounds that occur frequently in diseases such as diabetes are challenging to diagnose and treat due to numerous possible etiologies and the variable efficacy of wound care products. With advanced age, skin wound healing is often delayed, leaving elderly patients at high risk for developing these chronic injuries. As it is challenging to discriminate age-related delays from disease-related chronicity, there is a critical need to develop new quantitative biomarkers that are sensitive to wound status. Multiphoton microscopy (MPM) techniques are well-suited for 3D imaging of epithelia and are capable of non-invasively detecting metabolic cofactors (NADH and FAD) without …

Improving Long-Term Vascular Graft Viability Using Peritoneal Pre-Implantation And Epsin-Mimetic Peptides, Mahyar Sameti

Theses and Dissertations

The primary goal of this project was to produce and develop a tissue-engineered small-diameter vascular graft which can replace the arteries and function well for long-term grafting. Implanting an electrospun tubular conduit into the peritoneal cavity to recruit autologous cells prior to grafting the conduit into the artery is a method to achieve this goal. Incorporating an epsin-mimetic peptide on the conduit prior to grafting is another proposed method to reach the goal. This will be accomplished through four complementary studies: (1) determining the effect of a pouch in peritoneal pre-implantation and reducing the potential peritoneal adhesion formation;(2) determining the …

Development Of A Deformation-Based Structural Health System With Contactless Sensors And Machine Learning For Health Characterization And Failure Prediction, Juan Camilo Avendano Arbelaez

Theses and Dissertations

This dissertation presents the design and development of a structural health monitoring (SHM) system specifically tailored for transportation infrastructure components, such as bridges. The proposed system collects data by using contactless sensors and performs health characterization and failure prediction. It is capable of simulating multiple load conditions on structures, identifying possible failure points, and detecting and predicting failure scenarios. Both hardware and software implementations of a model of a bridge were performed as a pilot project in order to validate the proposed system. Computer simulation in ANSYS and the application of gradient boosting neural networks were performed to produce a …

A Finite State Automata-Based Description Of Device States For Function Modeling Of Multi-State Technical Devices, Ahmed Mohammed Sobhan Chowdhury

Theses and Dissertations

Many modern and innovative design problems require multi-modal, reconfigurable solutions. Function modeling (FM) is a common tool used to explore solutions in early stages of mechanical engineering design. Currently, function structure representations do not abet the modeling of formally-defined reconfigurable function models as graph-based function models used in early-stage systems design usually represent only one operational mode of the system. Currently there is a need, but no rigorous formalism to model multiple possible modes in the model and logically predict the behavior of the system as it transitions between the modes. Additionally, function modeling representations will benefit from dynamically capturing …

Application Of Compressive Sensing To Microwave Tomography, Rafael Gerardo Lopez

Open Access Theses & Dissertations

Microwave tomography(MT) allows the safe, non-intrusive examination of the internal structureof an object by irradiating it with microwave signals and measuring how they get attenuated and diffracted as they propagate through the object. Measurement of these signals is difficult and slow, it depends on the objectâ??s physical properties and the test setup used for this. MT is based on a scanning process that yields measurement data with unique characteristics that make it difficult to process using standard computational methods. As the number of measurements needed for an image with acceptable resolution increases, the complexity of processing all the data becomes …

Homotopy Simulation Of Dissipative Micropolar Flow And Heat Transfer From A Two-Dimensional Body With Heat Sink Effect: Applications In Polymer Coating, O. A. Bég, B. Vasu, A. K. Ray, T. A. Beg, A. Kadir, H. J. Leonard, Rama S. R. Gorla

Faculty Publications

Non-Newtonian flow from a wedge constitutes a fundamental problem in chemical engineering systems and is relevant to processing of polymers, coating systems, etc. Motivated by such applications, the homotopy analysis method (HAM) was employed to obtain semi-analytical solutions for thermal convection boundary layer flow of incompressible micropolar fluid from a two-dimensional body (wedge). Viscous dissipation and heat sink effects were included. The non-dimensional boundary value problem emerges as a system of nonlinear coupled ordinary differential equations, by virtue of suitable coordinate transformations. The so-called Falkner-Skan flow cases are elaborated. Validation of the HAM solutions was achieved with earlier simpler models, …

Performance And Efficiency Evaluation Of Stormwater Management Lids Using Pcswmm: Numerical Modeling And Sensitivity Analysis, Abdullah Al Fatta

Theses and Dissertations

Implementation of Low Impact Development systems (LIDs) can reduce the detrimental effects of urbanization. In this study, performance of both conventional drainage system and bioretention swales LID green infrastructure was assessed. Personal Computer Storm Water Management Model (PCSWMM) was used to investigate the performance by producing runoff hydrographs. Calibration and validation were conducted with independent storm events to minimize the gap between the simulated and observed outflow. Among different sensitive parameters, saturated hydraulic conductivity, suction head, percent initially saturated, Manning’s N for impervious area, were used in calibration. Each storm event resulted coefficient of determination (R2) values of 0.656 or …

A Python-Based Brain-Computer Interface Package For Neural Data Analysis, Md Hasan Anowar

Theses and Dissertations

Anowar, Md Hasan, A Python-based Brain-Computer Interface Package for Neural Data Analysis. Master of Science (MS), December, 2020, 70 pp., 4 tables, 23 figures, 74 references.

Although a growing amount of research has been dedicated to neural engineering, only a handful of software packages are available for brain signal processing. Popular brain-computer interface packages depend on commercial software products such as MATLAB. Moreover, almost every brain-computer interface software is designed for a specific neuro-biological signal; there is no single Python-based package that supports motor imagery, sleep, and stimulated brain signal analysis. The necessity to introduce a brain-computer interface package that …

Electromagnetic Interference Shielding Effectiveness Of Interlayered Systems Containing Metal-Oxide, Conducting Polymer And Carbon Nanotube Reinforced Polymeric Composites, Shaik Merkatur Hakim Marjuban

Theses and Dissertations

The Electromagnetic Interference (EMI) Shielding Effectiveness (SE) has become one of the important requirements for the devices associated with telecommunication systems consisting of large frequency bands. The degradation of the quality of transmitting signal influenced by frequencies emitting from external sources can be reduced by covering the circuits of the devices by EMI Shielding materials like polymer composites, metal-based nanofiber mats, the metal of oxide films, etc. The investigation strives for the attenuation of EMI by introducing two composite mats from conducting polymer-based, multiwalled carbon nanotubes (MWCNTs) coated Nylon 6 nanofiber composites. Two other composite mats are also developed by …

Stem Education In College: An Analysis Of Stakeholders’ Recent Challenges And Potential Solutions, Santanu De, Georgina Arguello

FDLA Journal

A vast majority of academic disciplines and curricula in the college center around Science, Technology, Engineering, and Mathematics (STEM), which are critical to developing the skills necessary for a global workforce. Rapid changes in pedagogical setups, educational modes, and advances in instructional technology entail diverse challenges for key stakeholders (i.e. students, faculty, and the organizations). This paper highlights the most relevant challenges and potential solutions in STEM higher education at the college level, reported in the last decade. The holistic analysis combining the three stakeholders’ perspectives would help elucidate significant contemporary aspects impacting the fields. The goal is to further …

Comparison Between Nano-Hydroxyapatite And Cpp-Acpf In Remineralizing Early Carious Lesions (In Vitro Study), Raneem Saudi, Mohamed A. Ibrahim

BAU Journal - Creative Sustainable Development

Poor oral hygiene, bacteria and orthodontic appliances mainly lead to early demineralized lesions where early detection and diagnosis of the lesion is a must so that it can be assessed and cured with the least invasive treatment. The objective was to evaluate the effect of nano-hydroxyapatite (nano-HA) and casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) on early demineralized enamel using DIAGNOdent pen and energy dispersive X-ray analysis (EDX). Materials and methods: A total of 60 enamel specimens were divided into four groups (n=15), where Group A: experimental; treated with nano-HA tooth paste, Group B: self-control for group A, Group C: experimental; …