Digital Commons Network^™

From Waste To Energy: The Electrochemical Reduction Of Co2 Using Recycled Nanostructured Catalysts, Ibrahim Badawy

Theses and Dissertations

The reduction of carbon dioxide (CO₂RR) using electrochemistry is a promising solution for the burgeoning global energy crisis. The overall vision of its implementation relies on renewable energy sources to power the reaction creating carbon neutral products and effectively closing the carbon cycle. Research in this field has come a long way since its inception in the mid-1900s. However, there remain significant hurdles and important considerations to overcome in order to reach full commercialization. Most electrocatalysts tested for CO₂RR have been designed solely for maximum performance while ignoring the environmental consequences if such a material were …

The Search For The Four-Electron Reduced Intermediate In The Cytochrome C Nitrite Reductase (Ccnir) - Catalyzed Reduction Of Nitrite, Victoria Lynn Mandella

Theses and Dissertations

Although there are many nitrogen species in the nitrogen cycle, nitrite occupies a centralrole. Nitrite can either reduce to ammonium or dinitrogen or oxidize to nitrate. Ammonium and nitrate can be found in the environment; however, problems arise when the accumulation of these nitrogen species leads to eutrophication in aquatic environments. High ammonium or nitrate levels in lakes or other bodies of water can lead to the overgrowth of algae, which causes the blockage of sunlight to different species below the water surface. Imbalance in the ecosystem is a serious environmental issue that can be addressed by further studying and …

Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen

Theses and Dissertations

The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …

Development And Characterization Of A Peanut-Shell Based Activated Carbon And The Outcomes Of A Hands-On Approach To Chemical Education, Danielle Pitre

Theses and Dissertations

Heavy metals are a recognized toxic environmental contaminant, even at very low concentrations. There have been well-known events in the last decade within the US of high amounts of lead in the drinking water supplies of cities, leading to detrimental effects within its population. Ways have been found to remove this metal, and others, from water with expensive adsorbents. The aim of the first part of this research was to create an inexpensive adsorbent from a waste material and modify it in such a way that it would be adept at removing heavy metals from water.

In Chapter I, we …

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 …

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 …

Behavioral Screening And Chiral Bioanalysis Of Emerging Stimulant-Type Drugs In Rats, Tyson R. Baird

Theses and Dissertations

The epidemic of drug use in the United States and elsewhere in the world has resulted in tragic loss of life and substantial economic costs. Novel psychoactive substances (NPS) are one of the contributors to this problem, and the lack of information about many of these drugs compounds their risk. This dissertation proposes a strategy to use intracranial self-stimulation (ICSS) as a behavioral screening tool to assess emerging drugs of abuse for their abuse potential in order to generate a proactive threat assessment. A series of stimulant-type drugs including methcathinone, α-pyrrolidinohexanophenone (α-PHP), cocaine, and the phenyltropane analogs of cocaine WIN35428 …

Analysis Of Microdroplets And Microorganisms By Single Entity Electrochemistry, Junaid U. Ahmed

Theses and Dissertations

Single Entity Electrochemistry (SEE) is an emerging electrochemical technique that has been used to characterize discrete entities by measuring the change in current or potential during individual stochastic events (collision or adsorption) of an entity with an ultramicroelectrode (UME) of similar dimensions. The shape and magnitude of the SEE signal depend on the underlying mechanism of interaction with the UME surface. There is a critical need for quantitative models that correlate the SEE signal with properties of the entity-UME system, including effects of acquisition instrumentation, to prevent misinterpretation of data.

This research focused on integrated experiments and simulations to quantify …

Characterization Of Small Molecules And Ions By Atmospheric Pressure Ionization-Mass Spectrometry, Maleesha De Silva

Theses and Dissertations

Mass spectrometry (MS) has become a widely used technique for the characterization of a wide range of substances in diverse fields. The selection of appropriate ionization techniques, source parameters, charge carriers based on the analyte’s polarity is essential in MS as only the ions are detected. When using a soft ionization technique, single stage-MS at best provides only chemical composition; thus, tandem MS is needed to determine structural information and dissociation pathways. This dissertation focuses on the characterization of various small molecules and ions using different ionization techniques, charge carriers, and collision-induced dissociation (CID).

In Chapter II, commercially available ionic …

Disease Biomarker Discovery And Fungal Metabolites Extraction Protocol Optimization Using Gcms Based Metabolomics, Chathuri Udeshika Gamlath Mohottige

Theses and Dissertations

Metabolomics is a powerful science that can be applied for the discovery of disease biomarkers, and investigation of altered metabolomes due to abiotic and biotic perturbations. This dissertation is focused on untargeted metabolomic applications to investigate fungal metabolite alterations associated with pathogenicity, fungal disease propagations, and symbiosis. This dissertation employs qualitative analysis of metabolite mixtures using HS-SPME coupled GC-MS and TMS derivatization followed by GC-MS analytical platforms. In the first study, we discovered a biomarker combination to diagnose fungal soft tissue disease in sweet potato at an early stage of disease propagation. We used an HS-SPME GC-MS untargeted metabolomics workflow …

Mass Spectrometry Directed Pre-Clinical Studies Of Asthma Candidate Midd0301 And Its Analogs, Md Shadiqur Rashid Roni

Theses and Dissertations

ABSTRACTMASS SPECTROMETRY DIRECTED PRE-CLINICAL STUDIES OF ASTHMA CANDIDATE MIDD0301 AND ITS ANALOGS by Md Shadiqur Rashid Roni The University of Wisconsin-Milwaukee, 2021 Under the Supervision of Professor Alexander (Leggy) Arnold

Asthma is one of the most prevalent global health problems. More than 25 million Americans are suffering from asthma and their symptoms especially in children are not well controlled with current medications. The current therapeutic options to control symptoms are limited and are commonly based on inhaled corticosteroids. There are several reasons for uncontrolled asthma symptoms that includes steroid resistance, improper use of inhalers and very few orally available medications. …

Solid Sorbents For Improved Chemical Separations: Applications In Nuclear Medicine And Environmental Remediation, Kevin Wolters

Theses and Dissertations

Solid sorbents have been applied to the separation of radionuclides since the advent of nuclear technology itself. First used for the cleanup and storage of radionuclides remaining from nuclear testing and nuclear power plants, these materials (e.g., inorganic and organic ion-exchange resins) were used to create solid nuclear waste forms as a way of reducing the potential for environmental contamination arising from storage of liquid wastes. The invention of nuclear medicine, which coincided with the introduction of nuclear technology, led to the need for high purity radionuclides for human use. One of the most widely used radionuclides in nuclear medicine …

Approach Toward The Total Synthesis Of Some Sarpagine Related Indole Alkaloids: Histrixnine, Gelsempervine A, Gelsempervine B, O-Methylmacusine B & 19,20-Dihydro-O-Methylmacusine B,Design, Synthesis & Biological Study Of Some Novel Gamma-Aminobutyric Acid Type (Gabaa) Receptor Ligands, Md Zubair Ahmed Khan

Theses and Dissertations

Indole alkaloids are chemically, biologically and commercially significant, as well as diversely distributed important group of natural products. These are of prominence because of their resemblance with various biologically essential molecules including tryptophan, tryptamine, and serotonin. The Sarpagine type indole alkaloids comprise one of the most diverse series of indole alkaloid natural products. These indole alkaloids are primarily isolated from three plant families: Apocynaceae, Rubiaceae, and Loganiaceae which have been used in traditional and folk medicines in many countries around the world. Biological screening of these alkaloids is not always possible, presumably, due to the paucity of the isolated natural …

Single Molecule Investigations Of Holliday Junction Binding Protein Ruva, Dalton Reed Gibbs

Theses and Dissertations

DNA breaks are inevitable as they mainly occur due to cells’ own reactive oxygen species (ROS). While DNA breaks can be single-stranded or double-stranded, the double-stranded DNA (dsDNA) breaks are more dangerous. If such damage is not repaired, it can lead to genetic instability and serious health issues including cancers. One way dsDNA breaks can be repaired is via a process called homologous recombination (HR), which involves several DNA-binding proteins. Therefore, to have a better insight into the repair mechanism and origin of repair defects, we need a better understanding of how these proteins interact with DNA itself and DNA …

Development Of A Novel Sequential Injection-Proton Nmr Method For Determining Cathinones In Forensic Samples, Malati Thapa

Theses and Dissertations

A novel method was developed for the determination of low levels of Cathinones in authentic samples by interfacing Sequential Injection Analysis (SIA) to Proton Nuclear Magnetic Resonance Spectroscopy (NMR). In the first part of this study, solid phase extraction (SPE) was studied by SIA to preconcentrate the sample and remove matrix interferences. Phenylpropanolamine (PPA), Phenylephrine (PEP), and Methylephedrine (MEP) were studied as simulants for the Cathinones, representing primary, secondary, and tertiary amines, respectively. A variety of stationary, mobile, and eluent phases for several column geometries were examined, and a wide cylindrical column (20 mm6.6 mm) with a bed volume of …

Adsorption Behavior Of Chemically / Charged Modified Antibodies On Gold Nanoparticles, Samuel Okyem

Theses and Dissertations

Gold nanoparticles (AuNPs) have been exploited in the various domains of science such as drug delivery, bio-sensing, immunoassays and environmental sensors, due to their optical properties and intriguing surface chemistry. Different scientific procedures have been used to effectively immobilize antibodies onto AuNPs. Although acceptable outcomes have been achieved in the immobilization of antibodies onto AuNPs, the sensitivity of these immobilized antibodies to target antigen or binding sites is limited due to improper orientation of the antibodies. Also, the possibility of nanoparticle aggregation when exposed to proteins limits its biomedical applicability.

There is some evidence that the surface charge of antibodies …

Characterization Of Dna Interstrand Cross-Linking Agents By Liquid Chromatograhy-Mass Spectrometry, Anahit Marina Campbell

Theses and Dissertations

This study is to characterize novel reactive oxygen species (ROS)-activated nitrogen mustard analogues and UV-activated alkylating agents by Liquid Chromatography-Mass Spectrometry (LC-MS). First, we optimized the instrument conditions to successfully ionize a few novel binapthalene analogues and methoxybenzene analogues by MS. The highest signal intensity for compounds 3-10 was observed when atmospheric pressure chemical ionization (APCI) with an optimized corona needle position of 5mm or 10 mm was used, which led to successful analysis of compounds 3-10 by MS. Second, we determined pharmacokinetic properties of a drug compound (FAN-NM-CH3), including animal study, assay development, optimization of MS/MS instrumental parameter and …

Zinc Proteomics: Interactions Of Zn2+, Cd2+, And Metal-Binding Ligands With Zn-Binding Sites In The Proteome, Eric Daniel Lund

Theses and Dissertations

Cadmium ion causes toxicity in humans, most prominently in the kidney. This thesis focuses on mechanisms by which Cd2+ harms kidney proximal tubule cells. Previous experiments have shown the time-dependent distribution of Cd2+ and Zn2+ within supernatant of pig kidney, LLC-PK1 cells after exposure to Cd2+ plus the ionophore pyrithione1. The first part of this research describes the trafficking of cadmium within LLC-PK1 proximal tubule cells, including the time dependent distribution, speciation, and quantification of Cd2+ and Zn2+ in cells exposed to Cd2+ and Cd2+ plus pyrithione. The latter treatment introduces Cd2+ into cells at time zero and permits the …

Potential For On-Site, Prosecutorial Evidence From Drug Residues Collected On Plasmonic Paper: A Pilot Study For Sers-Psi-Ms, Daniel S. Burr

Theses and Dissertations

Given the potential impact of improvements to on-site drug testing, as well as recent, successful displays of paper spray ionization mass spectrometry (PSI-MS) in this regard, this thesis pilots the implementation of Raman spectroscopy as a compliment to MS for field-based confirmatory drug testing. Surface enhanced Raman scattering (SERS) is utilized for applications to trace detection. Two-tiered analysis of individual drug samples is enabled using triangularly-cut plasmonic papers, from which both SERS and PS-MS analysis may be performed. Several drug compounds, representative of traditional and emerging drug types, are examined by these techniques, both separately and as a fully integrated, …

2nd Tier Assay For The Detection Of Congenital Adrenal Hyperplasia By Virginia’S Newborn Screening Laboratory: Steroid Profile By Hplc-Ms/Ms, Christopher E. Nixon

Theses and Dissertations

Congenital Adrenal Hyperplasia (CAH) encompasses several disorders related to disruptions in the adrenal steroid production pathway. These disruptions may cause virilization of the external female sex organs, incorrect gender assignment, precocious puberty, and in the most severe form, may cause life-threatening salt wasting and adrenal crisis if not detected and treated early in the newborn period.

17α-Hydroxyprogesterone (17-OHP) is the primary target for immunofluorescence detection of CAH from dried blood spots in newborn screening (NBS). Unfortunately, current immunoassay techniques for the detection of CAH suffer from high false positive rates. The primary factors contributing to false positive determinations can include …

Development And Characterization Of Stationary Phase Gradients For High Performance Liquid Chromatography, Anna Forzano

Theses and Dissertations

Choosing a stationary phase is the first step in developing a liquid chromatography (LC) separation method, where the selectivity is governed by the differential interactions of the analytes with the stationary and mobile phases. Introducing a gradient in stationary phase functionality allows for tuning of analyte retention, translating to a possible improvement in selectivity and an increase in resolution versus that offered by uniform stationary phases.

In this work, C₁₈-silica, phenylbutyl-silica, and phenylbutyl-ammonium opposed continuous stationary phase gradients were fabricated using controlled rate infusion (CRI) on particle packed LC columns. Characterization of the stationary phase was carried out …

Studies In Molecular Recognition: Non-Proteogenic Amino Acids For Antibiotic Studies And Chemosensors For Recognition And Reporting Of Metal-Ions, Sarah Anne Oehm

Theses and Dissertations

The field of molecular recognition focuses on the selective and reversible binding of small guest molecules to larger host molecules. This dissertation describes synthesis of small molecules as binding guests for enzymatic substrates as well as molecules as host chemosensors to detect and identify metal ions. Two approaches to new antibiotic drugs have been explored, and an array of sensors for the quantitation of aqueous metals is being commercialized.

As strains of deadly bacteria emerge with evolved resistance to known antibiotics, new drugs are needed with novel mechanisms of action. Natural product antibiotics containing enduracididine, a non-canonical amino acid derived …

Biosensing And Catalysis Applications Of Nanoporous Gold (Npg) And Platinum-Speckled Nanoporous Gold (Npg-Pt) Electrodes, Christopher J. Freeman

Theses and Dissertations

The importance of porous materials has risen substantially in the last few decades due to their ability to reduce the size and cost of bioanalytical devices and fuel cells. First, this work aims to describe the fabrication of nanoporous gold (NPG) electrodes that are resistant to electrode passivation due to fibrinogen biofouling in redox solutions. The effect on potentiometric and voltammetric experiments was seen as a deviation from ideal behavior on planar gold electrodes, whereas NPG electrodes were consistently behaving in a Nernstian fashion at low concentrations of ferri-ferrocyanide (£100 mM). An improvement in electrode behavior on NPG electrodes versus …

Heteroatom Doped Porous Carbon For Alternative Energy Conversion And Storage Systems, Fatema A. Choudhury

Theses and Dissertations

Abstract

The electrocatalysis of oxygen plays a significant role in several electrochemical energy storage and conversion systems including metal−air batteries, fuel cells, electrocatalytic and photocatalytic water splitting. The sluggish kinetics and complex reaction mechanism of this cathodic oxygen reduction reaction (ORR) affect the performance and practical application of such renewable energy technologies. To address this limiting factor, a suitable electrocatalyst is required for ORR. In general, platinum or highly dispersed Pt-based nanoparticles on carbon black are considered as the best ORR catalyst. But platinum being very scarce and expensive tends to increase the cost. Moreover, platinum-based catalysts are prone to …

Mechanistic Studies Of Proton-Coupled Electron Transfer Reactions Involving Antioxidants, Kejie Meng

Theses and Dissertations

The objective of the research was to investigate proton-coupled electron transfer (PCET) reactions involving antioxidants to gain insight into the detailed mechanisms of glutathione (GSH), Trolox, and α-tocopherol (α-TOH). PCET reactions are complex redox reactions that transfer electrons and protons sequentially or in concert. These reactions are ubiquitous in natural or artificial processes that produce electrochemical energy that is extractable as electricity or as chemical fuels of high energy content. Examples of processes based on PCET are photosynthesis, respiration, nitrogen fixation, carbon dioxide reduction, redox fuel cells, and artificial photosynthesis. Antioxidants were selected as a PCET model to understand the …

Development Of Pre-Clinical Assays Based On Tandem Mass Spectrometry To Investigate Gabaa Receptor Modulators, Margaret Laurel Guthrie

Theses and Dissertations

ABSTRACT

DEVELOPMENT OF PRE-CLINICAL ASSAYS BASED ON TANDEM MASS SPECTROMETRY TO INVESTIGATE GABAA RECEPTOR MODULATORS

by

Margaret L. Guthrie

The University of Wisconsin – Milwaukee, 2017

Under the Supervision of Professor Alexander (Leggy) Arnold

Drugs are compounds that interact with a biological system to produce a specific biological response. The goal of drug discovery is to design and synthesize a pharmaceutical agent that will produce a desired biological effect. However, the in-vivo effects of a drug molecule cannot be predicted without a variety of test results prior to human clinical trials. In order to designate any drug compound as a …

Part – I: Development Of A Two-Step Regiospecific Synthetic Route For Multigram Scale Synthesis Of Β-Carboline Analogs For Studies In Primates As Anti-Alcohol Agents,Part – Ii: Design And Synthesis Of Novel Antimicrobials For The Treatment Of Drug Resistant Bacterial Infections Part – Iii: A Novel Synthetic Method For The Synthesis Of The Key Quinine Metabolite (3s)-3-Hydroxyquinine, Veera Venkata Naga Phani Babu Tiruveedhula

Theses and Dissertations

PART – I

Development of a Two-Step Regiospecifc Synthetic Route for Multigram-Scale Synthesis of β-Carboline Analogs for Studies in Primates as Anti-Alcohol Agents

β-Carboline and their derivatives are important structural motifs in synthetic organic and medicinal chemistry because of their novel biological activity, especially in regard to the reduction of alcohol self-administration [binge drinking (BD)], a major problem increasing day by day in modern society. This anti-alcohol effect is proposed to be due to the activity of ligands at the benzodiazepine site of the GABAA receptor in the central nervous system acting as antagonists at the α1 subunit. The past …

Fundamental Studies Of Metal Ion Extraction Into Ionic Liquids By Macrocyclic Polyethers, James Lee Wankowski

Theses and Dissertations

The liquid-liquid extraction (LLX) of metal ions from aqueous media into ionic liquids (ILs) by macrocyclic polyethers has proven to be an efficient and selective, but complex approach to their separation. Partitioning in these systems has previously been described using a so-called ‘three-path’ model comprising three distinct extraction pathways: neutral complex / ion pair extraction, exchange of the IL cation for a metal-extractant complex, and exchange of the metal ion for a hydronium ion bound to the extractant. The balance of these three paths has been reported to be affected by several characteristics of the LLX system, including the structure …

Development Of General Purpose Liquid Chromatography Simulator For The Exploration Of Novel Liquid Chromatographic Strategies, Lena N. Jeong

Theses and Dissertations

The method development process in liquid chromatography (LC) involves optimization of a variety of method parameters including stationary phase chemistry, column temperature, initial and final mobile phase compositions, and gradient time when gradient mobile phases are used. Here, a general simulation program to predict the results (i.e., retention time, peak width and peak shape) of LC separations, with the ability to study various complex chromatographic conditions is described. The simulation program is based on the Craig distribution model where the column is divided into discrete distance (Δz) and time (Δt) segments in a grid and is …

Separation Of Transition And Heavy Metals Using Stationary Phase Gradients And Chelation Thin Layer Chromatography / Evaluation Of The Effectiveness Of Pogil-Pcl Workshops, Stacy L. Stegall

Theses and Dissertations

Gradient surfaces exhibit a variation in functionality along the length of the surface. One method for preparing gradients is controlled-rate infusion (CRI). In Part 1 of this work, CRI was used to prepare gradients for the purpose of separating transition and heavy metals. Initial work on this project was focused on controlling the retention of the metal ions by varying the number of amine groups, aminoalkoxysilane concentration, and the infusion time. The retention factors of four metal ions varied predictably with increasing number of amine groups, increasing aminoalkoxysilane concentration, and increasing infusion time, producing small but useful changes in the …