Chemistry Commons^™

Mechanisms And Impact Of Hypoxia Regulated Inhibins In Cancer, Ben Allen Horst

Theses and Dissertations

Inhibins are heterodimeric ligands within the TGFβ superfamily, comprised of an α-subunit (INHA) and a β-subunit (either INHBA or INHBB) with emergent roles in cancer. Inhibins are biomarkers of disease burden and prognosis in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Previously, we found inhibin promotes angiogenesis in ovarian cancer however no mechanism of regulation for inhibin expression in cancer has been established. Hypoxia, a driver of tumor growth and metastasis, regulates angiogenic pathways that are targets for vessel normalization and ovarian cancer management. …

Materials Discovery By Flux Crystal Growth: Synthesis, Structure Determination, Magnetic, And Optical Properties Of Complex Oxides, Oxychlorides, And Oxyfluorides, Darren Andrew Carone

Theses and Dissertations

Exploratory crystal growth has proven to be a successful technique in the synthesis of new compounds with desired properties. This method is very versatile and has various iterations, but results described herein were obtained through flux growth at high temperatures utilizing mixed alkali halide salts. The tunability of these reactions with respect to reactant ratios, reaction temperature, heating/cooling rates, metal precursors, and choice of flux allow for the exploration of phase spaces between a combination of elements and observation of significantly different products and/or structure types from minor tweaks.

Most of the research presented in this dissertation describes results that …

Crystal Growth Of Inorganic Halides And Oxide-Halides For Scintillation Applications And Radiation Detection, Gyanendra B. Ayer

Theses and Dissertations

Scintillators, materials which emit light when struck by high energy X-rays and y- rays, are extensively used in various fields including medical imaging, computed tomography, high-energy physics, and more recently in homeland security for the prevention of nuclear and radiological terrorism. While comparing with the traditional scintillators, which have long-term instability, high synthetic cost, toxicity, and hygroscopicity issues, metal halides have been reported to exhibit effective excitonic radioluminescence and greatly contribute in the field of scintillating applications and radiation detection. Currently, the mixed-anion oxide-fluorides have emerged as a prospective new class of scintillators, in which the mixed oxide-fluoride environment …

Novel Synthetic Strategies Toward Polyolefin-Grafted Nanoparticles, Richard Tran Ly

Theses and Dissertations

Surface functionalization of nanoparticles has proven to be a powerful and versatile strategy in the development of various materials with advanced properties. Polymer brush composition can range from complex copolymers to more simplistic polyolefin, and by functionalizing nanoparticle surfaces, mobility of distinct particles can then be tuned and, therefore, control over dispersion in a polymer matrix can be achieved. Presented in this dissertation are new synthetic strategies for the preparation of polymer nanocomposites.

The first chapter covers a novel synthetic strategy for ethylene/propylene-like copolymers grafted to silica nanoparticles. This approach utilizes Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization to promote living …

Enhancing Vanadium Redox Battery Performance Using Tungsten-Bismuth-Based Oxide Nanostructures As Electrode Modifiers, Taher Al Najjar

Theses and Dissertations

Renewable energy power plants require high efficiency conversion and storage systems that can store high amounts of energy and can be integrated with the electrical grid. Vanadium redox flow batteries are very promising for this application. However, one major drawback of VRFBs is their low power density which means that right now they cannot replace non-renewable energy sources. Different carbon materials are used as electrodes in VRFBs and each carbon material affects the battery’s performance in a different way. Modification of these electrodes can increase the power density of the battery. Some metal oxides like tungsten oxide can enhance vanadium …

Synthesis Of Conjugated Polymers From Xanthene And Alkenyl Flanked Diketopyrrolopyrrole Monomers For High-Performance Electronic Applications., Ranganath Wijesinghe Wahalathantrige Don

Theses and Dissertations

In traditional electronics, inorganic materials such as silicon and germanium are used as semiconductors due to their outstanding semiconducting properties. Unfortunately, inorganic materials are rigid due to their high crystalline nature, and processing these materials is complex and expensive. Furthermore, traditional semiconducting materials do not have favorable mechanical properties in applications such as wearable devices and large-area applications with complicated shapes. Conjugated conducting polymers (CCPs) are being explored as alternative materials to conventional semiconductors due to their mechanical properties and high conductivity. CCPs offer properties such as solution and low-temperature processability, flexibility, thermal and optical properties that traditional semiconductors could …

Phosphorus Enriched Modified-Douglas Fir Biochar As A Soil Amendment, Beatrice Arwenyo

Theses and Dissertations

Biochar application as a soil additive is gaining global acceptance. In this era of climate change, biochar use for improved soil productivity is not just a sustainable eco-friendly substitute to synthetic fertilizer, but a noble contributor to the fight against climate change. Although biochar has been accredited with some environmental and agricultural benefits, most studies concentrated on agricultural and biowaste products as feedstocks. This research was designed to explore P-enriched modified-Douglas fir biochar potential as a soil additive. Using corn as a test crop, greenhouse studies were performed on acidic sandy soil, comparing phosphorus enriched modified-Douglas fir biochar efficacy to …

Functionalized Biochar Electrodes For Asymmetric Capacitive Deionization, Hellen Stephanie

Theses and Dissertations

Electrosorption-based capacitive deionization (CDI) has become a viable process for brackish water desalination and defluoridation. In this study, activated Douglas fir biochar is used as a low-cost electrode material with adsorption capacity comparable to activated carbon obtained from biomass precursors. Adding functional groups to the activated biochar enhanced salt removal capacity, providing cation and anion selectivity. The functionalized electrodes were prepared by Nafion, titanium isopropoxide, and p-phenylenediamine treatment, respectively, which introduced sulfonate, titanium dioxide and amine functional groups to the electrode surface. These modification methods are versatile and can be easily performed without sophisticated laboratory environment. Modified biochar electrodes …

A Modular Synthesis Of Processable And Thermally Stable Semi-Fluorinated Aryl Ether Polymers Via Step-Growth Polymerization Of Fluoroalkenes, Ketki Eknath Shelar

Theses and Dissertations

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The …

Insights Into Molecular Recognition And Reactivity From Molecular Simulations Of Protein-Ligand Interactions Using Md And Qm/Mm, Jerrano L. Bowleg

Theses and Dissertations

In this thesis, we have employed two computational methods, molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) MD simulations with umbrella sampling (US), to gain insights into the molecular mechanism governing the molecular recognition and reactivity in several protein-ligand complexes. Three systems involving protein-ligand interactions are examined in this dissertation utilizing well-established computational methodologies and mathematical modeling. The three proteins studied here are acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1). These enzymes are known to interact with a variety of ligands. AChE dysfunction caused by organophosphorus (OP) chemicals is a severe hazard since AChE is …

Step-Growth Polymerization Of Perfluoro-Vinyl Ether, -Cycloalkenes, And -Acyclic Alkenes With Bisphenols Containing Variable Polycyclic Aromatic Cores, Karl Mpumbwa Mukeba

Theses and Dissertations

This dissertation reports the synthesis and characterization of semi-fluorinated polymers derived from the polymerization of bisphenols with fluoroalkenes. A series of diverse bisphenols were chosen from popular commercial bisphenols and new polycyclic aromatic hydrocarbon (PAH) derived bisphenols requiring synthesis. Step-growth condensation polymerization of bisphenols with three different fluoroalkene types was performed while probing polymerization conditions and the structure/properties relationship of the resulting fluoropolymers. The fluoroalkene monomers were chosen from bis(trifluorovinyloxy)biphenyl (TFVE), perfluorocyclohexene (PFCH), and perfluoro acyclic monomers, namely, perfluoro(4-methyl-2-pentene) and 1-perfluoroheptene to undergo this chemistry.

This work is divided into four parts based on the polymerization methodology.

The first …

Synthesis And Characterization Of Sustainable And Biobased Copolymers From Lignocellulosic, Guery Saenz

Theses and Dissertations

Natural compounds have been the primary resource used to produce polymeric materials by humankind since the mid-1900s. Yet, progress in bio-based polymers from renewable feedstock has encountered some obstacles, mainly due to the low prices of petroleum-based monomers, compared to natural and sustainable materials. However, most commodity plastics are non-degradable materials, and solid plastic waste accumulation adversely affects the environment. As the world population is growing and demanding chemicals, energy, and plastics materials, polymer research is focusing on synthesizing bio-based and degradable polymers. Thus, biomass, a sustainable and inexpensive feedstock, is highly appropriate for designing alternative thermoplastics that are degradable …

Synthesis Of Gpr119 Interacting Drugs For Treatment Of Type Ii Diabetes, Tien M. Tran

Theses and Dissertations

Type II Diabetes is one of the leading causes of death in the United States and is categorized by high blood glucose levels, insulin deficiencies, and inhibition. Located in the pancreas and intestine, the G-Protein Receptor 119 (GPR119) was noted to have an important effect on insulin secretion. Previous studies found that when the receptor is activated, insulin secretion was upregulated which is vital for type II diabetes treatment. Compounds AR437735 and AR437948 are the proposed agonist and inverse agonist pair that will be synthesized and tested for bioactivity to the receptor. It is theorized that the different double-bonded atoms …

Development Of Diagnostic Tools And Analysis Of The Density Functional Theory Zoo, Pierpaolo Morgante

Theses and Dissertations

The main goal of this dissertation is to give an overview of existing and new databases for density functional theory (DFT). It describes the procedures used to introduce A Collection of Chemistry DataBases (ACCDB) and its reduction to a smaller and statistically significant database called A Small(er) Collection of DataBase (ASCDB). Also, it presents an application of such databases in chemical education through the introduction of a notebook of twelve exercises that can easily complement a computational chemistry class. In addition, a new database of molecules having carbon-carbon long bonds (CLB18) is presented. Last, the databases are used in the …

Total Synthesis Of Mansouramycin A, Abigail M. Zepeda

Theses and Dissertations

In 2009 bioactive compounds from marine Streptomyces species was isolated which resulted in deriving four isoquinoline-quinone alkaloids known as Mansouramycins A-D. There have been reports that there are 36 non-small cancer cells against cytotoxicity in Mansouramycins A-C in lung cancer, breast cancer, melanoma, and prostate cancer cells. Reports that have conducted total syntheses were all specific to a single compound only Mansouramycin A and D. However, in precedent methods, to obtain the derivatives with different substituents are limited when the substituents are on the fused-pyridine ring. Thus, a develop a systematic synthetic methods of isoquinoline-quinones, which are to be able …

Structural Analysis Of [Ni(Dippe)] Fragment Using Computational Methods, Jennifer L. Sanchez

Theses and Dissertations

The structural analysis of the Nickel (Bisdiisopropylphospino)ethane, also known as [Ni(dippe)H]2, has been heavily studied in our group in collaboration with William D. Jones's group. A computational analysis of the [Ni(dippe)] fragment was performed to determine the structural relationship between the nickel center and its phosphine ligand, due to phosphines having both electronic and steric properties. The reactivity of the Nickel will be most dependent on the dippe ligand. A conformational search generated 244 conformers after a thorough minimization using Molecular Mechanic (MM) calculations where a thorough minimization was performed and then re-minimized using a SEED command until unique conformers …

Control Of Irradiation Wavelength And Quantum Yield Of Photocleavable Cages, Jingxuan Ma

Theses and Dissertations

An important component of biological research is the precise regulation of biomolecules in their physiological environment. Recent advances in neuroscience, have made it possible to regulate the activity of neurotransmitters using photocleavable protecting groups (PPGs), which are also known as cages. This enables the use of light as a trigger to activate selected neurons via photo release of agonists with precise control of timing as well as synaptic site, popularly referred to as spatiotemporal control. In recent years, a variety of PPGs have been developed and applied to biomolecular cages. PPGs can be classified according to their absorption wavelengths (from …

Synthesis, Characterization And Activity Of Palladium Catalysts On The Dual Support Of Cerium And Aluminum Oxides, Jihyeon Park

Theses and Dissertations

The effects of sequence of impregnation (Pd on cerium oxides -alumina and cerium oxides on Pd-alumina) and calcination temperature (500 ℃ and 850 ℃) on the catalytic oxidation of methane under lean conditions were investigated. The catalysts were prepared by a combination of impregnation, slurry and vortexing methods. The catalysts had 4.7 wt.% Pd and 10.7 wt.% Ce based on inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The catalysts were characterized by pulse chemisorption, temperature programmed reduction (TPD), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). The activity of the catalysts for methane combustion was measured in …

Sustainable Polymers: Upcycling Poly(Vinyl Chloride) And Mimicking Low Density Polyethylene, Ian Baxter

Theses and Dissertations

In this research, increasing the sustainability of polymers was investigated through two main methods. The upcycling of poly(vinyl chloride) and the creation of polymer mimics to create degradable low-density polyethylene. In the first chapter, an overview of the sustainability issues of polymers is presented and approaches are described on how their sustainability may be increased through the upcycling of polymers or the synthesis of degradable polymers that mimic the properties of petrol-based polymers.

Chapter 2 contains the progress on the upcycling of PVC using high oleic soybean oil. Soybean oil can soften PVC making it less brittle than pure PVC. …

Photophysics And Electronic Properties Of Photochromic Metal-Organic Frameworks, Corey R. Martin

Theses and Dissertations

Modulation of materials properties through light-based illumination has the capability to expand the technology sector due to stimuli-responsive dynamic behavior that cannot be achieved in traditional materials. For example, reversibly tuning photophysical profiles of such materials allows for switching between discrete states that is a key aspect for the developing logic gates, spatially- and temporally-resolved sensors, and on-demand drug delivery systems. My efforts have focused on employment of metal-organic frameworks (MOFs) as a versatile platform for the material development which contain photochromic moieties allowing for tailoring their electronic properties. Our group has expanded this direction to include heterometallic and actinide-containing …

Well–Defined Donor–Acceptor Materials, Gabrielle A. Leith

Theses and Dissertations

The modularity of multivariant scaffolds such as covalent–organic frameworks (COFs) provides an unprecedented level of control in the alignment of donor (D) and acceptor (A) units, a demand that is driven by the production of optoelectronic, photonic, and spintronic devices. The foray into novel motifs bearing D-A ensembles in frameworks has been applied towards material property modulation for device performance enhancement. This dissertation presents an emerging trend in the development of D-A interfaces by highlighting recent advances probing D-A interactions in porous crystalline matrices and co-crystals, with a focus on energy transfer (ET) and charge transfer (CT) processes in pre-designed …

Metal Free Bond Activation By Carboranyl Phosphines, Gayathri B. Gange

Theses and Dissertations

In the past few decades, main group-based catalysts have attracted increasing attention as an alternative approach to overcome the most prevailing issues of transition metal catalysts such as high cost, toxicity, and low abundance. Among these main groupbased catalysts, Phosphine based compounds have shown a variety of bond activations due to the strong nucleophilicity from their congener species. To the contrary, unique electron deficient boron-based clusters have the tendency to accept two electrons reversibly due to their electron deficiency. In this study, we have synchronized the electron donor ability of the phosphine with the electron acceptor ability of the ortho …

Synthesis Of Carborane Pincer Complexes And Exploration Of The Reactivity Of Metal-Boron Bonds, Hindurangalage Don Asela Chathumal Jayaweera

Theses and Dissertations

Exploration of transition metal complexes with metal-boron bonds for the cooperative bond activation of small molecules in catalysis is one of the recent developments in novel synthetic strategies. The use of boron clusters as a modular platform for the formation of metal-boron bond has been successfully utilized by our and other groups. Carboranes are icosahedral boron-carbon molecular clusters that have gained attraction as multifunctional ligands due to their unique geometry, electronic properties, and versatility of functionalization methods. Their 3-D structure exerts a steric bulk around the exohedral substituent, either metal or non-metal center. Furthermore, due to the cluster geometry, five …

Tailored Nanomaterials For Advancing Fast-Charge Research, Wessel Van Den Bergh

Theses and Dissertations

The demand for fast, energy-dense storage has driven research into nanoscale intercalation materials. Nanoscale materials not only accelerate kinetics but also can modify reaction path thermodynamics, intercalant solubility, and diffusivity. Pioneering works have revealed such nanoscale changes, often without the need to separately probe each fundamental transport process. While electrodes can be designed to have one transport processes dominant, there remain opportunities to better understand energy-dense designs with multiple concomitant transport constraints. The contents herein highlight emerging an method using tailored, energy-dense nanomaterials and the process of elimination to clearly correlate architectural features to performance. For example, this method revealed …

Adsorption Of Microcystins To Sediment Affects Their Bioavailability And Remediation, Ashley Womer

Theses and Dissertations

The freshwater harmful algae Microcystis spp produces a family of toxins called microcystins1. These species of algae are known to release microcystins from their cells directly into the surrounding water2. This creates an array of human health risks depending on the fate and transport of the toxins in the water column3,4. Risk modelling and previous literature has shown that sediment is a sink for free microcystin, microcystin can be stably adsorbed to sediment for hundreds of years, and its adsorption to sediment is determined by the sediment adsorption partitioning coefficient (Kd)5,6,7. In this work it is hypothesized that the sediment …

Mechanistic Understanding Of Catalytic Processes For Sustainable Chemical Transformations, Pooja J. Ayare

Theses and Dissertations

The current field of catalysis is notably advanced in terms of both conceptual and technical innovation. There is a constant need to design new catalysts and develop catalytic processes to improve the scope, efficiency, and selectivity of various chemical transformations. It is also imperative to design catalytic systems which are effective, truly-recyclable and energy efficient for a sustainable future. This can be done through comprehensive knowledge and understanding of catalyst behavior, reaction kinetics and process designing.

For most industrial processes, the preferred catalysts are heterogeneous because these solid catalysts can be easily separated from the final product. However, they often …

Modification Of Active Sites In Catalytic Materials For Gas-Phase Heterogeneous Catalysis, Deependra Man Shakya

Theses and Dissertations

Heterogeneous catalysis remains at the core of chemical manufacturing industries with 80-90 % of chemical processes relying on the use of catalysts. Unlike homogeneous catalyst that has extremely well-defined active sites, active sites in heterogeneous catalysis are complex and show dynamic behavior under reaction conditions, and change their structures, composition, particle size. The complexity associated with these systems has made the rational design of the catalyst a difficult problem. Highly crystalline metalorganic frameworks (MOFs) as heterogeneous catalysts present the unique opportunity to systematically modify the geometries, ensemble sizes, and compositions of highly dispersed active sites due to their tailorable, and …

Atomistic Simulation Of Na+ And Cl- Ions Binding Mechanisms To Tobermorite 14Å As A Model For Alkali Activated Cements, Ahmed Abdelkawy

Theses and Dissertations

The production of ordinary Portland cement (OPC) is responsible for ~8% of all man-made CO2 emissions. Unfortunately, due to the continuous increase in the number of construction projects, and since virtually all projects depend on hardened cement from the hydration of OPC as the main binding material, the production of OPC is not expected to decrease. Alkali-activated cement produced from the alkaline activation of byproducts of industries, such as iron and coal industries, or processed clays represents a potential substitute for OPC. However, the interaction of the reaction products of AAC with corrosive ions from the environment, such as Cl-, …

Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem

Theses and Dissertations

Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …

Transition Metal Phosphides For High Performance Electrochemical Energy Storage Devices, Amina Saleh

Theses and Dissertations

Electrochemical energy storage technologies are nowadays playing a leading role in the global effort to address the energy challenges. A lot of attention has been devoted to designing hybrid devices known as supercapatteries which combine the merits of supercapacitors (high power density) and rechargeable batteries (high energy density). Transition metal phosphides (TMP) are a rising star for supercapattery anode materials thanks to their high conductivity, metalloid characteristics, and kinetic favorability for fast electron transport. Herein, new TMP-based materials were synthesized for use as supercapattery positive electrodes, via a multifaceted approach to yield devices enjoying concurrently high power and energy densities. …