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Articles 31 - 60 of 511

Full-Text Articles in Biomedical Engineering and Bioengineering

Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum Aug 2018

Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum

Chemical and Biomolecular Engineering -- All Faculty Papers

When carbohydrates are fermented by the hyperthermophilic anaerobe Thermotoga maritima, molecular hydrogen (H2) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H2 through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded by ldh) with a truncated ldh ...


Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie Jun 2018

Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie

Chemical and Biological Engineering Publications

Gellan gum is a naturally occurring polymer that can cross-link in the presence of divalent cations to form biocompatible hydrogels. However, physically cross-linked gellan gum hydrogels lose their stability under physiological conditions, thus restricting the applications of these hydrogels in vivo. To improve the mechanical strength of the gels, we incorporated methacrylate into the gellan gum and chemically cross-linked the hydrogel through three polymerization methods: step growth through thiol–ene photoclick chemistry, chain-growth via photopolymerization, and mixed model in which both mechanisms were employed. Methacrylation was confirmed and quantified by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared ...


Process Analytics From Passive Acoustic Emissions Monitoring During Fluidized Bed Pellet Coating In Pharmaceutical Manufacturing, Allan Carter Jun 2018

Process Analytics From Passive Acoustic Emissions Monitoring During Fluidized Bed Pellet Coating In Pharmaceutical Manufacturing, Allan Carter

Electronic Thesis and Dissertation Repository

Piezoelectric microphones were attached to a top spray fluidized bed to provide valuable process signatures. Relationships were developed between sound waves and conditions within the fluidized bed to relay critical quality and performance information. Deep learning analytics were used to extract valuable information from experimental data. Advancements in passive acoustic emissions monitoring will play a key role in optimizing pharmaceutical manufacturing pathways to ensure drug quality and performance.


Preparation Of Supramolecular Amphiphilic Cyclodextrin Bilayer Vesicles For Pharmaceutical Applications, Kate E. Frischkorn Jun 2018

Preparation Of Supramolecular Amphiphilic Cyclodextrin Bilayer Vesicles For Pharmaceutical Applications, Kate E. Frischkorn

Master's Theses and Project Reports

Recent pharmaceutical developments have investigated using supramolecular nanoparticles in order to increase the bioavailability and solubility of drugs delivered in various methods. Modification of the carbohydrate cyclodextrin increases the ability to encapsulate hydrophobic pharmaceutical molecules by forming a carrier with a hydrophobic core and hydrophilic exterior. Guest molecules are commonly added to these inclusion complexes in order to add stability and further increase targeting abilities of the carriers. One such guest molecule is adamantine combined with a poly(ethylene glycol) chain. Vesicles are formed by hydrating a thin film of amphiphilic cyclodextrin and guest molecules in buffer solution that mimics ...


Chemotherapeutic Drug Cytotoxicity Measurement With A 3d Biomimetic Microfluidic Device And Computational Fluid Dynamics Model, Maryam Moarefian, Caroline Jones, Luke Achenie, Danesh Tafti May 2018

Chemotherapeutic Drug Cytotoxicity Measurement With A 3d Biomimetic Microfluidic Device And Computational Fluid Dynamics Model, Maryam Moarefian, Caroline Jones, Luke Achenie, Danesh Tafti

Biology and Medicine Through Mathematics Conference

No abstract provided.


Modeling Pharmaceutical Inhibition Of Glucose-Stimulated Renin-Angiotensin System In Kidneys, Ashlee N. Ford Versypt, Minu R. Pilvankar, Hui Ling Yong May 2018

Modeling Pharmaceutical Inhibition Of Glucose-Stimulated Renin-Angiotensin System In Kidneys, Ashlee N. Ford Versypt, Minu R. Pilvankar, Hui Ling Yong

Biology and Medicine Through Mathematics Conference

No abstract provided.


Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender May 2018

Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender

Student Theses 2015-Present

This paper aims to shed light on the dissonance caused by the superimposition of Dominant Human Systems on Natural Systems. I highlight the synthetic nature of Dominant Human Systems as egoic and linguistic phenomenon manufactured by a mere portion of the human population, which renders them inherently oppressive unto peoples and landscapes whose wisdom were barred from the design process. In pursuing a radical pragmatic approach to mending the simultaneous oppression and destruction of the human being and the earth, I highlight the necessity of minimizing entropic chaos caused by excess energy expenditure, an essential feature of systems that aim ...


Antibacterial Properties Of A Cationic Imidazolium-Containing Poly(Ionic Liquid), Kaitlyn P. Brickey May 2018

Antibacterial Properties Of A Cationic Imidazolium-Containing Poly(Ionic Liquid), Kaitlyn P. Brickey

Biomedical Engineering Undergraduate Honors Theses

Poly(ionic liquids), or PILs, have been shown to have a number of biological applications as ligands, drug delivery vehicles, and nonviral DNA delivery mechanisms. Additionally, PILs have been proven to be efficient antibacterials. Imidazolium-containing PILs have promising results in antibacterial studies, but relating to their chain and charge density, only the effects of mono- & bis-imidazolium PILs have been sufficiently described in literature. The work detailed in this thesis aimed to further existing research on the effect of chain density by controlling the UV-initiator immobilization time. The effects of chain density were investigated by grafting poly(vinylimidazolium chloride) onto SiO ...


Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee Mar 2018

Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee

Bruce Lee

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface ...


Covalently Crosslinked Organic/Inorganic Hybrid Biomaterials For Bone Tissue Engineering Applications, Dibakar Mondal Feb 2018

Covalently Crosslinked Organic/Inorganic Hybrid Biomaterials For Bone Tissue Engineering Applications, Dibakar Mondal

Electronic Thesis and Dissertation Repository

Scaffolds are key components for bone tissue engineering and regeneration. They guide new bone formation by mimicking bone extracellular matrix for cell recruitment and proliferation. Ideally, scaffolds for bone tissue engineering need to be osteoconductive, osteoinductive, porous, degradable and mechanically competent. As a single material can not provide all these requirements, composites of several biomaterials are viable solutions to combine various properties. However, conventional composites fail to fulfil these requirements due to their distinct phases at the microscopic level. Organic/inorganic (O/I) class II hybrid biomaterials, where the organic and inorganic phases are chemically crosslinked on a molecular scale ...


Thermal Fusion For Sutureless Closure: Devices, Composition, Methods, Eric Anthony Kramer Jan 2018

Thermal Fusion For Sutureless Closure: Devices, Composition, Methods, Eric Anthony Kramer

Mechanical Engineering Graduate Theses & Dissertations

As minimally invasive surgical techniques progress, the demand for reliable ligation is pronounced. The surgical advantages of energy-based vessel sealing exceed those of traditional, compression-based ligatures in procedures sensitive to duration, foreign bodies, and recovery time alike. While the use of energy-based devices to seal or transect vasculature and connective tissue bundles is widespread, the breadth of heating strategies and energy dosimetry used between devices underscores an uncertainty as to the molecular nature of the sealing mechanism and induced tissue bond. Further, energy-based techniques (e.g., tissue “fusion” or tissue “welding”) exhibit promise for the closure, repair and functional recovery ...


Comparison Of Eosin And Fluorescein Conjugates For The Photoinitiation Of Cell-Compatible Polymer Coatings, Jacob L. Lilly, Anuhya Gottipati, Calvin F. Cahall, Mohamed Agoub, Brad J. Berron Jan 2018

Comparison Of Eosin And Fluorescein Conjugates For The Photoinitiation Of Cell-Compatible Polymer Coatings, Jacob L. Lilly, Anuhya Gottipati, Calvin F. Cahall, Mohamed Agoub, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more ...


Modeling Liver Diseases Using Hepatic Cell Microarrays, Alexander David Roth Jan 2018

Modeling Liver Diseases Using Hepatic Cell Microarrays, Alexander David Roth

ETD Archive

Hepatocellular carcinoma (HCC) is an invasive and aggressive cancer of the liver that arises due to chronic cirrhosis. Research into understanding HCC has focused on two-dimensional (2D) and three-dimensional (3D) technologies to simulate the liver microenvironment and use animal models to model how HCC affects the rest of the body. 3D hydrogel models are desired because they can mimic the transport behavior observed in vivo by structurally mimicking the extracellular matrix (ECM) without the ethical concerns of animal models. However, hydrogels can be toxic to cells and require optimal procedures for appropriate handling. In this study, we created 3D models ...


The Role Of Protein-Protein Interactions In Inducing Interfacial Aggregation, Lea Line Gisele Sorret Jan 2018

The Role Of Protein-Protein Interactions In Inducing Interfacial Aggregation, Lea Line Gisele Sorret

Chemical & Biological Engineering Graduate Theses & Dissertations

The synergic exposure to silicone oil-water interfaces and to agitation has been shown to promote the aggregation of therapeutic proteins. Silicone oil is typically used as a lubricant for manufacturing surfaces and pharmaceutical containers such as glass prefilled syringes. This is a problem as protein aggregates formed at the silicone oil-water interface may shed into bulk solutions, leading to product recalls or adverse immunogenicity upon injections into patients.

Protein aggregation in solution occurs as a result of attractive protein-protein interactions (PPI). PPI can be characterized using techniques such as dynamic light scattering which measures the dependence of molecular diffusivity on ...


Modifying Supported Palladium Catalysts Using Self-Assembled Monolayers For Liquid-Phase Reactions, Pengxiao Hao Jan 2018

Modifying Supported Palladium Catalysts Using Self-Assembled Monolayers For Liquid-Phase Reactions, Pengxiao Hao

Chemical & Biological Engineering Graduate Theses & Dissertations

In this thesis, we investigate the modification of Pd/Al2O3 catalyst using thiolate and phosphonate self-assembled monolayers (SAMs) for two types of reactions in liquid-phase environments: selective oxidation of α, β-unsaturated alcohols and vanillin hydrodeoxygenation. Through the study, we aim to gain a better understanding of the liquid-solid interface that governs the catalytic activity.

The selective oxidation of a linear unsaturated alcohol trans-2-hexen-1-ol (HOL) was studied on Pd/Al2O3 catalysts in heptane. Alkanethiolate self-assembled monolayers (SAMs) were applied to modify Pd/Al2O3 catalysts; the sulfur content on the Pd surface was ...


Application Of Advances In Synthetic Biology To Modular Megasynthase Design And Scalable Combinatorial Biosynthesis, William Clifford Grau Jan 2018

Application Of Advances In Synthetic Biology To Modular Megasynthase Design And Scalable Combinatorial Biosynthesis, William Clifford Grau

Chemistry & Biochemistry Graduate Theses & Dissertations (1986-2018)

The diversity in structure and biological activity of natural products has long captured the imagination of chemists and molecular biologists alike. Natural products are synthesized by elaborate secondary metabolic pathways or enzymes. For example, modular megasynthases such as Type I Polyketide Synthases (PKSs), Non-ribosomal Peptide Synthetases (NRPSs), and PKS-NRPS hybrids, produce an array of quintessential natural products. The apparent modularity, defined architecture, and predictable chemistry of modular megasynthases make them especially attractive for combinatorial biosynthesis, which has long been a focus of biotechnology. Combinatorial biosynthetic libraries are of particular interest due to the high value of many natural products and ...


Connecting Protein Structure And Dynamics On Biomaterials With The Foreign Body Response, David Faulon Marruecos Jan 2018

Connecting Protein Structure And Dynamics On Biomaterials With The Foreign Body Response, David Faulon Marruecos

Chemical & Biological Engineering Graduate Theses & Dissertations

The harsh environment of the foreign body response (FBR) has the potential to negatively impact the implantations of biomaterials in the body. The FBR is initiated by inflammatory cells that recognize the material as foreign through surface-adsorbed proteins. When proteins interact with surfaces, they can unfold and expose epitopes that may be recognized by immune cells and trigger a series of reactions. Importantly, the presentation of unfolded proteins is directly influenced by the highly dynamic and heterogeneous behavior of proteins in near-surface environments, as well as by the physicochemical features of the underlying surface. Such behavior is the result of ...


Multicatalytic, Light-Driven Reactions For Improved Biofuels And Wastewater Remediation, Glenn Richard Hafenstine Jan 2018

Multicatalytic, Light-Driven Reactions For Improved Biofuels And Wastewater Remediation, Glenn Richard Hafenstine

Chemical & Biological Engineering Graduate Theses & Dissertations

Utilizing solar driven photocatalysis to facilitate coupling reaction systems is a promising route for low-energy and selective production of valuable chemicals. My doctoral research has focused on using photocatalytic cadmium sulfide nanorods to run novel reaction systems under mild, ambient conditions with sunlight as the only energy source. In this dissertation, I will first describe a cascade reaction system for catalytic upgrading of the fermentation products butanol and ethanol into an easily separated product in 2-ethylhexenal with a higher energy density. Specifically, I will report the use of the enzyme alcohol dehydrogenase, regeneration of the enzymatic cofactor by the photocatalyst ...


Engineering The Phospholipid Monolayer On Fluorocarbon, Hydrocarbon, And Liquid Crystal Nanodroplets For Applications In Biosensing, Rajarshi Chattaraj Jan 2018

Engineering The Phospholipid Monolayer On Fluorocarbon, Hydrocarbon, And Liquid Crystal Nanodroplets For Applications In Biosensing, Rajarshi Chattaraj

Mechanical Engineering Graduate Theses & Dissertations

Nanodroplets (NDs) are liquid-in-liquid dispersions of ~100-800 nm size range that are often stabilized by a shell of lipids, polymer, proteins, or surfactants. NDs have been explored for a variety of biomedical applications, mostly involving drug formulation and delivery. However, the unique properties of encapsulated liquids, and the effects of interfacial chemistry on these properties, makes NDs potentially powerful candidates for new biosensing technologies. This dissertation explores different oil-in-water or fluorocarbon-in-water ND systems for in-solution sensing of biomarkers as both a platform for diagnostic assays and as a precursor to in vivo biosensing. Nanodroplets, because of their size, provide a ...


Development Of Entubulation Strategies For Treating Central Nervous System Injuries, Ivy Brosch Jan 2018

Development Of Entubulation Strategies For Treating Central Nervous System Injuries, Ivy Brosch

Williams Honors College, Honors Research Projects

According to the McKnight Brain Institute, at least 10,000 people annually in the USA suffer from a central nervous system (CNS) injury. These injuries can cause serve disabilities including paralysis. Due to the complexity of the spinal cord, it is common that potential CNS treatments are first applied to an optic nerve crush (ONC) model in rats. Two proposed treatments were employed; one where nerve growth factor (NGF) was immobilized to a chitosan substrate to stimulate axonal regeneration, and the other using pentadecafluorooctanoyl chloride modified methacrylamide chitosan (MAC(Ali15)F) hydrogel to enhance local oxygenation. The two different treatments ...


Molded Features In Pdms For Fabricating Bacterial Cellulose For Various Geometries, Mitchell Habegger Jan 2018

Molded Features In Pdms For Fabricating Bacterial Cellulose For Various Geometries, Mitchell Habegger

Williams Honors College, Honors Research Projects

The purpose of producing features on bacterial cellulose (BC) is to facilitate the elongation and alignment for cells, in this case Normal Human Dermal Fibroblast (NHDF) cells. The elongated cells have applications in wound healing, tissue engineering, disease diagnostics, and many other fields. Experiments were run to test the effectiveness of transferring features to BC sheets from features induced by fracturing on polydimethylsiloxane (PDMS) and those duplicated from molds with existing features. The features were duplicated to BC sheets by either air drying or Guided Assembly-Based Biolithography (GAB). The research results showed that fracture inducing on PDMS produced very small ...


Surface Functionalization Via Photoinitiated Radical Polymerization For Rare Cell Isolation And Mechanical Protection, Calvin Frank Cahall Jan 2018

Surface Functionalization Via Photoinitiated Radical Polymerization For Rare Cell Isolation And Mechanical Protection, Calvin Frank Cahall

Theses and Dissertations--Chemical and Materials Engineering

Surface functionalization of living cells for cell therapeutics has gained substantial momentum in the last two decades. From encapsulating islets of Langerhans, to cell laden gels for tissue scaffolds, to individual cell encapsulation in thin hydrogels, to surface adhesives and inert surface camouflage, modification of living cell surfaces has a wide array of important applications. Here we use hydrogel encapsulation of individual cells as a mode of protection from mechanical forces for high throughput cell printing, and chemical stimuli for the isolation of rare cells in blood.

In the first study, we review methods of surface functionalization and establish a ...


High-Throughput Metabolism-Induced Toxicity Assays On A 384-Pillar Plate, Sooyeion Kang Jan 2018

High-Throughput Metabolism-Induced Toxicity Assays On A 384-Pillar Plate, Sooyeion Kang

ETD Archive

The U.S Environmental Protection Agency (EPA) launched the Transform Tox Testing Challenge in 2016 with the goal of developing practical methods that can be integrated into conventional high-throughput screening (HTS) assays to better predict the toxicity of parent compounds and their metabolites in vivo. In response to this need and to retrofit existing HTS assays for assessing metabolism-induced toxicity of compounds, we have developed a 384-pillar plate that is complementary to traditional 384-well plates and ideally suited for culturing human cells in three dimensions (3D) at a microscale. Briefly, human embryonic kidney (HEK) 293 cells in a mixture of ...


Collagen Organization Deposited By Fibroblasts Encapsulated In Ph Responsive Methacrylated Alginate Hydrogels, Anuraag Boddupalli, Kaitlin M. Bratlie Jan 2018

Collagen Organization Deposited By Fibroblasts Encapsulated In Ph Responsive Methacrylated Alginate Hydrogels, Anuraag Boddupalli, Kaitlin M. Bratlie

Materials Science and Engineering Publications

The pH of dermal wounds shifts from neutral during the inflammatory phase to slightly basic in the tissue remodeling phase. Stage specific wound treatment can be developed using environmentally responsive alginate hydrogels. The chemistry of these networks dictates swelling behavior. Here, we fabricated alginate hydrogels using chain growth, step growth, and combined mixed mode gelation methods to crosslink methacrylated alginate (ALGMA) and gain control over swelling responses. Methacrylation of the alginate network was confirmed through NMR spectroscopy. Strontium cations were introduced to fabricate stiffer, dually crosslinked hydrogels. Dual crosslinking significantly decreased the swelling response over the pH range of 3 ...


Biophysical Features Of The Extracellular Matrix Direct Breast Cancer Metastasis, Alyssa Schwartz Jan 2018

Biophysical Features Of The Extracellular Matrix Direct Breast Cancer Metastasis, Alyssa Schwartz

Doctoral Dissertations

Breast cancer is plagued by two key clinical challenges; drug resistance and metastasis. Most work to date probes these events on an extremely rigid plastic surface, which recapitulates few aspects of these processes in humans. A malignant cell first resides in breast tissue, then likely travels to the bone, brain, liver, or lung, each of which has a distinct mechanical and biochemical profile. Cells transmit mechanical forces into intracellular tension and biochemical signaling events, and here we hypothesize that this mechanotransduction influences drug response, growth, and migration.

To probe the impact of extracellular matrix on drug resistance, we defined a ...


Structure-Property Relationships Of Polymer Films And Hydrogels To Control Bacterial Adhesion, Kristopher W. Kolewe Jan 2018

Structure-Property Relationships Of Polymer Films And Hydrogels To Control Bacterial Adhesion, Kristopher W. Kolewe

Doctoral Dissertations

The emergence and spread of antibiotic resistance across microbial species necessitates the need for alternative approaches to mitigate the risk of infection without relying on commercial antibiotics. Biofilm-related infections are a class of notoriously difficult to treat healthcare-associated infections that frequently develop on the surface of implanted medical devices. As biofilm formation is a surface-associated phenomenon, understanding how the intrinsic properties of materials affect bacterial adhesion enables the development of structure-property relationships that can guide the future design of infection-resistant materials. Despite lacking visual, auditory, and olfactory perception, bacteria still manage to sense and attach to surfaces. Previously, it has ...


Characterization Of Bacteriorhodopsin And Halorhodopsin Reconstituted In Lipid Bilayer Membranes, Joel Domkam Kamwa Jan 2018

Characterization Of Bacteriorhodopsin And Halorhodopsin Reconstituted In Lipid Bilayer Membranes, Joel Domkam Kamwa

Theses and Dissertations

Motivated to produce electricity with photon activated ion pumps, the main purpose of this work was to characterize the photosynthetic membrane proteins bacteriorhodopsin (proton pump) and halorhodopsin (chloride pump). The proteins were re-suspended in lipid bilayers. For this work, an experimental set-up was built which included: chambers for lipid bilayer formation and characterization, lasers for ion pump activation, and an AxoPatch electrophysiology system for small photocurrent measurement. Lipid bilayer membranes were formed using mostly folding method: folding two monolayers together. The membranes were characterized by their resistance, capacitance, and generated photocurrent. Photocurrent was generated upon illumination of lipid-protein membranes with ...


Modeling Of Reaction-Diffusion Transport Into A Core-Shell Geometry, Clarence C. King, Amelia Ann Brown, Irmak Sargin, Kaitlin M. Bratlie, S. P. Beckman Jan 2018

Modeling Of Reaction-Diffusion Transport Into A Core-Shell Geometry, Clarence C. King, Amelia Ann Brown, Irmak Sargin, Kaitlin M. Bratlie, S. P. Beckman

Materials Science and Engineering Publications

Fickian diffusion into a core-shell geometry is modeled. The interior core mimics pancreatic Langerhan islets and the exterior shell acts as inert protection. The consumption of oxygen diffusing into the cells is approximated using Michaelis-Menten kinetics. The problem is transformed to dimensionless units and solved numerically. Two regimes are identified, one that is diffusion limited and the other consumption limited. A regression is fit that describes the concentration at the center of the cells as a function of the relevant physical parameters. It is determined that, in a cell culture environment, the cells will remain viable as long as the ...


An Application Of M-Matrices To Preserve Bounded Positive Solutions To The Evolution Equations Of Biofilm Models, Richard S. Landry Jr. Dec 2017

An Application Of M-Matrices To Preserve Bounded Positive Solutions To The Evolution Equations Of Biofilm Models, Richard S. Landry Jr.

University of New Orleans Theses and Dissertations

In this work, we design a linear, two step implicit finite difference method to approximate the solutions of a biological system that describes the interaction between a microbial colony and a surrounding substrate. Three separate models are analyzed, all of which can be described as systems of partial differential equations (PDE)s with nonlinear diffusion and reaction, where the biological colony grows and decays based on the substrate bioavailability. The systems under investigation are all complex models describing the dynamics of biological films. In view of the difficulties to calculate analytical solutions of the models, we design here a numerical ...


Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed Dec 2017

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of ...