Physical Sciences and Mathematics Commons^™

Cognitive Engagement During Group Learning Activities In Chemistry Courses: An Analysis Of Student Discourse, Safaa Youssef El-Mansy

Dissertations and Theses

As educators, our goal is to help our students be successful, but in order to accomplish this, we need to understand what factors contribute to student success. One factor, small-group active learning, has been correlated to improved academic outcomes; however, the magnitude of this improvement can vary across different courses, different types of group work, and even across courses that use the same group work structure. Therefore, it is important to understand what aspects of group work contribute to its effectiveness. The work presented in this dissertation investigated one specific aspect: students’ cognitive engagement. This was done by analyzing the …

Electrochemical Hydrogen Gas Production And Carbon Dioxide Sequestration Via In Situ Formation Of Nickel (Ii) Tris-(Pyridinethiolate) Derivatives, Dayalis S.V. Brown

Dissertations and Theses

In the research presented, we use electrochemical techniques, such as cyclic voltammetry and controlled potential electrolysis, to study in situ formation of hydrogen evolution catalysts which also reduce carbon dioxide. Using pyridinethiol-based ligands and a nickel (II) precursor, both homo- and heteroleptic complexes were investigated as catalysts to produce alternative fuels while mitigating greenhouse gas emissions. Existing synthetic procedures to obtain these Ni(II) catalysts lead to low yields of the complexes and difficulties in crystallizing samples for further analysis, limiting sample size and restricting the number of studies. While current research is heavily focused on photochemically-driven experiments, given that solar …

Studies On Bonding, Syntheses, And Applications Of Diarylhalonium Compounds, Shubhendu Karandikar

Dissertations and Theses

Organic compounds containing functionalized benzenoid rings have found tremendous applications in pharmaceuticals, agrochemicals, commodity chemicals, and beyond. As a result, development of methods for the synthesis of functionalized benzenoid rings has gained much attention from the synthetic community. Although many transition-metal mediated methods to functionalize benzenoid rings are known, there has been an upsurge of activity in developing protocols for decoration of benzenoid cores promoted by p-block elements. This excitement stems from the sustainability of earth-abundant elements and unique reactivity patterns observed within the p-block. Among these, transformations promoted by hypervalent halogen compounds, and especially, the diarylhalonium salts are very …

Nmr Analyses Of Flavored E-Cigarette Liquids Before And After Aerosolization, Paul Joseph Kerber

Dissertations and Theses

Electronic cigarettes (e-cigarettes) are the most commonly used tobacco products among adolescents with ~11 and ~3% of high school and middle school students reporting past 30 day use in 2021 according to the Centers for Disease Control and Prevention (CDC), respectively. Furthermore, greater than ~80% of high school and middle school e-cigarette consumers use flavored e-liquids. Consumers can be exposed to variable toxicant levels upon e-liquid aerosolization, depending on the composition of the e-liquid, type of e-cigarette, e-cigarette settings, and other customizations.

E-liquids are typically composed of a carrier solvent (propylene glycol (PG) and glycerol (GL)), flavorants, and nicotine. PG …

Exploring Structure-Function Relationship In Small-Molecular Catalysts Using Computational And Experimental Methodologies, Avik Bhattacharjee

Dissertations and Theses

Molecular modeling is a useful tool in the field of catalyst design for various processes. The use of Density Functional Theory (DFT) is routine in almost every discipline of chemistry. This allows for a deeper understanding of a molecular system even in situations where implementation of an experimental technique is unfeasible. However, without the right choice of theory and insufficient description, the model becomes susceptible to produce ambiguous results. This often leads to poor correlation with experimental findings hence an incomplete understanding of the system under study. Hence, to acquire a thorough knowledge of the intricacies involved in a system, …

Detection And Quantification Of Arsenic Pollution With A Moss Bio-Indicator And Icp-Ms, Erin R. Bowey

University Honors Theses

Heavy metal pollution is a recognized concern with an established source of anthropogenic activity, which is ever-increasing. While work has been done to make the monitoring of some metals more accessible, resourceful, and efficient with the use of epiphytic moss as a bio-indicator, this method has not been optimized for the detection of arsenic. Previously used analytical instrumentation has not proven sensitive enough to reliably detect arsenic, creating a gap in the monitoring process. However, inductively coupled plasma mass spectrometry (ICP-MS) is proposed as the solution to fill this gap. Its potential for low limits of detection and quantification express …

Synthesis Of Diaryl And Alkyl-Aryl Ethers Via Diaryl Iodonium Reagents, Rory Tennessee Gallagher

Dissertations and Theses

Substituted benzenoid rings are a prevalent motif in many industries including high tech, agrochemicals, and pharmaceuticals. As a result, the arylation of chemical compounds is a highly sought-after chemical transformation. There are many literature methods to achieve this chemical transformation, nucleophilic aromatic substitution and transition metal catalysis are both widely used and studied. Diaryliodonium salt mediated chemistry is an attractive alternative to these methods as it does not require the expensive toxic metals and designer ligands of transition metal catalysis and is not restricted to electron deficient aryl rings with specific substitution patterns like nucleophilic aromatic substitution.

Many diaryliodonium salt …

Efficient Capture Of Co2 And Its Selective Reduction To Formic Acid Using Tin-Based Nanomaterials, Emmanuel Oluwaseun Abdul

Dissertations and Theses

CO₂ emissions from the combustion of fossil fuels and other anthropogenic sources have become the main contributing factors to global warming. Chemical methods of absorbing/capturing CO₂ from combustion flue gases have made it a sought-after approach in engineering emission solutions because of its simplistic and convenient operation and high absorption efficiency. The conversion of CO₂ into renewable fuels and high energy density chemicals by clean and economic processes has drawn scientists' attention over the decades. The electrocatalytic conversion of CO₂ using Sn-based materials has been demonstrated to be a promising method for producing formate, an important …

Speciation Of Diaryliodonium Salts In Solution And Their Reactivity Towards N-Nucleophiles (Phthalimide And Amines) And O-Nucleophiles (Phenols And Phenoxide), Souradeep Basu

Dissertations and Theses

Benzenoid rings are prevalent in pharmaceutical drug molecules, agrochemical molecules and even in some polymers used in electronic device. Aryl rings are often installed using metal catalysis, however, metal free arylations are known but limited. Diaryliodonium salts are novel electrophilic arylating agents. Herein, metal free N-arylation of phthalimide and diarylether formation using aryl(TMP)iodonium salts is described.

The structure of diaryliodonium salts has been primarily studied in either the solid state or in-silico. The structure and speciation of diaryliodonium salts in solution is not well explored. In this work evidence of dimer formation of aryl(Mes)iodonium salts in chloroform using …

A Biomimetic Model For Oxidative Metabolism Of Thiopurine Drugs, Oluyemi Oludare Alo

Dissertations and Theses

Type B hepatotoxicity has been reported for thiopurines, and this has limited their clinical uses. Although a lot of research has been done on thiopurines, the precise mechanism of their hepatotoxicity is still unclear. The results of the in vitro and in vivo experiments aimed at assessing the products of their CYP450-mediated bioactivation have been contradictory. Although it has been theorized that the hepatic toxicity of this class of drug is caused by their bioactivation to electrophilic reactive metabolite (RM) and concomitant protein binding to form immunogenic adducts, resulting in direct cellular dysfunction or an immune response via the formation …

Materials And Methodologies For Spectroscopic And Optical Analytical Applications In Cultural Heritage Conservation Science, Lyndsay Nichole Kissell

Dissertations and Theses

The field of conservation science falls in the intersection of science and art. The work of conservation scientists may include any single subdiscipline of chemistry, though it is most commonly a highly interdisciplinary field taking skills from analytical, organic, and inorganic chemistry, as well as surface and materials science. The aims of conservation scientists are to answer questions about the production and aging of material cultural heritage. Knowing the materials used by an artist can lead to insight about the intentions of the object and knowing how those materials degrade will enable the use of preventative measures to ensure the …

Rapid Method For Consistency And Concentration Reporting Of Cannabidiol Using 1H-Nmr And Computer-Assisted Chemical Software, Michael A. Fernando

University Honors Theses

An integrated computational method was demonstrated with hemp-derived Cannabidiol for an assessment of its purity and concentration. The sample was structurally verified, high purity, and 2.98 mmol/L in dissolved DMSO. The method presented is a general approach to assessing purity and concentration for any small organic molecule in CMC-Assist.

Exploring The Potential Use Of Porous Silica Nanoparticles In Cest-Mri, Lydia Makotamo

Dissertations and Theses

Magnetic resonance imaging (MRI) is a widely used modality in diagnostics, treatment, and monitoring various conditions due to its ability to generate high-resolution images using non-ionizing radiation. The advent of contrast agents, which generally work by increasing the spin relaxation rate constants of water protons, has led to image enhancement. Despite the usefulness of this class of agents in diagnostic medicine, their inability to provide in-depth functional and anatomical information, coupled with their high detection limits, has led to new agents being explored.

Chemical exchange saturation transfer (CEST) presents an alternative route to generate signals via repetitive saturations transfers between …

Designing Environmentally Responsible And Highly Effective Bioorthogonally Functionalized Chiral Mri Contrast Agents, Karley Breann Maier

Dissertations and Theses

Magnetic resonance imaging (MRI) revolutionized diagnostic imaging and modernized the characterization of numerous diseases. The clinical success of MRI is in large part due to the employment of gadolinium-based contrast agents (GBCAs). Due to sensitivity limitations, GBCAs are indicated at markedly high dosages (~1 g Gd³⁺ per exam). The routine use of such large quantities of gadolinium poses significant health and environmental risks. There are growing concerns over the effects of dechelation of the metal in vivo and the possible effect of resulting gadolinium deposition. Concurrently, there is a rising awareness of gadolinium anomalies borne by GBCAs which undergo …

Selenium Probes For The Detection Of Thioredoxin Reductase Activity, Tendai Joseph Mafireyi

Dissertations and Theses

The identification and quantification of proteins and enzymatic activity in living tissues frequently requires the use of invasive procedures such as biopsy. These techniques can inhibit measurements of protein levels in real-time, and the disruption of tissue can lead to the loss of important information concerning the spatial distribution and differential activities in various cell types. The use of small organic fluorescent probes that rely on activation or accumulation within a tissue embody robust methods of detection that address these issues. This dissertation describes the design, synthesis and evaluation of fluorescent probes that can detect the enzyme thioredoxin reductase (TrxR). …

Mechanistic Investigation Of Neuropeptide S-Nitrosylation By Nitric Oxide Moieties: A Kinetic And Thermodynamic Approach, Vusumuzi Leroy Sibanda

Dissertations and Theses

This dissertation focuses on providing quantitative insights regarding kinetic, thermodynamic and mechanistic parameters of neuropeptide S-nitrosylation by nitrous acid (HNO₂), peroxynitrite (ONOO^-) and S-nitroso-N-acetyl-D,L-penicillamine (SNAP) to produce S-nitrosothiols (SNOs). Peptide thiol stability and the formation of SNOs from neuropeptides; arginine vasopressin (AVP), somatostatin-14 (SST-14) and urotensin II (U-II) was studied. Investigations into the effects of temperature, copper chelators and pH on peptide thiol autoxidation show that AVP, SST-14 and U-II thiols have half-lives of 30, 44 and 28.2 mins respectively at physiologically relevant temperature and pH in the absence of metal chelators. Target peptide thiols were …

The Development And Application Of Instrumental Methods For The Identification Of Materials And Processes Used In The Manufacture Of Orotone, Hand-Colored Orotone, And Silvertone Photographs, Ivanny Jeannette Jácome-Valladares

Dissertations and Theses

Orotone photographs are positive photographic images on glass with a gold-colored metallic coating or backing. Although the materials and process used in the production of orotones have been previously documented, there is limited published scientific research on the subject. This study focused on expanding those published works by analyzing a greater number of photographs, including eleven orotones, four hand-colored orotones, two silvertones, and one uncoated orotone. The photographs, dating from the early to mid-20^th century, were from the University of Washington (UW) Libraries' collection, except for one orotone that was from the Portland Art Museum.

X-ray Fluorescence (XRF) spectroscopy, …

Soft Lithographic Replication Of High Length-Scale Micropillars From Laser-Ablated Fused-Silica Templates, Jason Pitts

University Honors Theses

Soft lithography is a well-established route to wafer-scale reproduction of micro- and nanoscale features in a wide variety of materials. Nevertheless, micron length scales have yet to be explored, despite the potential utility of such structures. Here, polymer micropillars of 6-12 μm length, approximately 0.5-1.5 μm wide at 10 μm spacing are reproduced from a polydimethylsiloxane (PDMS) mold made from patterned cellulose acetate (CA). The patterned CA was cast from a rigid fused silica template machined by a pulsed femtosecond laser. Pore topographic features were successfully reproduced in Norland Optical Adhesive (NOA), polycaprolactone (PCL), Nafion, acrylonitrile butadiene styrene (ABS), and …

Tellurorhodamine Photocatalysts In Aerobic Oxidation Reactions: Development Of Synthetic Methods And Reaction Mechanisms, Irving D. Rettig

Dissertations and Theses

Aerobic oxidation photocatalysis involves the use of oxygen as an oxidant species, coupled to a light driven catalyst to achieve useful chemical transformations. Catalytic aerobic oxidation reactions can be defined as either oxidase-like, in which O₂ acts as an electron donor/acceptor but is not incorporated into the reaction products, or oxygenase-like where O₂ acts as an electron donor/acceptor and is incorporated into the reaction products. A multitude of inorganic catalysts have been developed that can achieve a wide scope of oxidase-like or oxygenase-like reactivity, however, it is rare for a catalyst to be capable of both. We report …

Investigations Into Size And Surface Control Of Silicon Nanocrystals For Improved Optical Properties, James Donald Barnes

Dissertations and Theses

The discovery of visible photoluminescence (PL) from nanocrystalline porous silicon in 1990 led to extensive research into the mechanisms of the emergent properties, and optimization of these properties, for use in applications. The widespread use of silicon nanoparticles (Si NPs) in commercial applications is currently limited by three main factors: 1) poor radiative recombination efficiency of the interband transition, 2) instability of the interband photoluminescence, and 3) a lack of scalable methods for producing Si NPs that are both highly crystalline and size monodisperse.

To address these limitations, this dissertation correlates changes in the photoluminescence properties of hydrogen passivated silicon …

Steady-State Transmembrane Water Exchange In Proliferating Cultures Of Saccharomyces Cerevisiae, Joseph O'Malley Armstrong

Dissertations and Theses

Cellular water exchange is often considered in terms of a change in volume, where a net flux of water moves across the cell membrane due to a change in osmotic pressure. Osmotic pressure can cause a cell to shrink or swell, however, rapid water exchange persists across the membrane even when the volume of the cell is constant. Steady-state transmembrane water exchange describes the exchange of water across the cell membranes which results in no net change in cell volume. This exchange is astonishingly rapid; the entire pool of intracellular water of a Saccharomyces cerevisiae cell may exchange 2-5 times …

Chemical Characterization Of Toxicologically Relevant Molecules In Cannabis Concentrates And Vaporizer Aerosols, Jiries Meehan-Atrash

Dissertations and Theses

Consumption of cannabis concentrates using the relatively novel non-combustion methods dabbing and vaping has steadily grown in popularity as cannabis legalization in North America has allowed increased access to sophisticated cannabis products and technology. In order to assess the safety of these products, it is necessary to gain a chemical understanding of the decomposition reactions that occur when the active ingredients are heated in the conditions seen when dabbing or vaping. This dissertation contains a manuscript that details efforts to structurally characterize a toxic cannabis concentrate adulterant, and three manuscripts that studied the chemical decomposition of the two primary cannabis …

Thermodynamics Of Ligand Binding And Global Structural Stability Of Human Serum Albumin, Matthew Walter Eskew

Dissertations and Theses

Protein structure is integral to its function. For the past 70 years differential scanning calorimetry has been used to measure protein structural stability. More recently it has been used to study macromolecular interactions. Interactions between proteins and ligands can manifest on differential scanning calorimetry melting curves or thermograms. Utilizing differential scanning calorimetry thermograms to detect or diagnose diseases has been a major goal in disease diagnostics. However, correlating specific ligand-protein interactions, as manifested in a thermogram, with a disease-specific plasma thermogram, has proven elusive.

Modified human serum albumin was utilized to develop a process to capture and retrieve ligands from …

Complex Fluid Dynamics: Chemo-Hydrodynamics Driven By Autocatalytic Reaction Fronts, Matthew Walter Eskew

Dissertations and Theses

Chemo-hydrodynamics generated from reaction-diffusion-convection processes of autocatalytic chemical systems are extensively studied for their applications in modeling complex systems. Compared to the more extensively studied autocatalytic systems, chlorite-tetrathionate and chlorite-trithionate, the chlorite-thiourea systems is relatively unexplored. Compared to the two previous systems, chlorite-thiourea has more straightforward chemical kinetics. To narrow the gap between chlorite-thiourea and the other systems a combination of experimental study and numerical simulation were employed to quantify this system.

Compared to established literature, experiments were performed at five orders of magnitude lower concentration of indicator, minimizing confounding effects of indicator on hydrodynamic motion. To accurately image the …

Identification Of Degradation Products Formed From Glycerol And Terpenes In Aromatherapy Vaporizers, Alisha Ortiz

University Honors Theses

Degradation chemistry has been widely studied to assess the safety of aerosols in many fields. The study herein investigates the degradation products formed from MONQ personal aromatherapy devices- a new non-nicotine aromatherapy vape pen device on the market. These pens are marketed to alleviate symptoms of an unrecognized medical syndrome called “terpene deficiency”. These pens contain a glycerin (GL), or glycerol (VG), base and a blend of terpene-rich essential oils. Previous studies have investigated the degradation of both VG and terpenes and have shown that concerning compounds are released in the gas phase, including benzene, benzaldehyde, methacrolein and methyl vinyl …

Aryne-Guided C-H Functionalization Of Benzenoid Rings Using Diaryliodonium Salts, Aleksandra Nilova

Dissertations and Theses

The benzenoid core is a frequent and irreplaceable component of biologically active molecules. Structure function relationship of these compounds has been broadly analyzed and presented in numerous literature reports. Herein, we augmented existing knowledge by a broad analysis of the benzenoid substitution patterns in small molecule active pharmaceutical ingredients approved by the FDA. Our findings reveal a strong correlation that the most represented substitution patterns are those achieved via S_EAr. Despite the rapid development of methods to functionalize benzenoid rings, the lack of synthetic methodologies to access sterically and electronically unfavorable positions is highlighted. We sought to establish …

Designing A More Effective Mri Contrast Agent: Investigation Into Various Functionalization Strategies For Targeted Imaging, Lauren Nicole Rust

Dissertations and Theses

Magnetic resonance imaging (MRI) is a medical imaging technique that provides high-resolution images used for diagnostic medicine while maintaining a superior safety profile compared to other radiative techniques. The administration of gadolinium-based contrast agents (GBCAs) improves the diagnostic power of MRI and have been used clinically for over three decades. Although GBCAs are effective at improving the contrast in the image, their detection limits are high and require a large dose to generate an observable effect. This high dose is the consequence of the current available designs of clinical GBCAs; their structures are not tuned to generate optimal efficacy. Efficacy …

Synthesis And Assessment Of Radiotherapy-Enhancing Nanoparticles, Hayden Winter

Dissertations and Theses

Radiation Therapy (RT) is a common treatment for cancerous lesions that acts by ionizing matter in the affected tissue, causing cell death. The disadvantage of RT is that it is most often delivered via an external beam of radiation which must pass through healthy tissues to reach the target site, ionizing matter within healthy tissues as well. To address this drawback, techniques are being developed for increasing RT-induced cell death in a target tissue while minimizing cell death in surrounding tissues. This effect is known as radiation dose enhancement or RT enhancement.

The approach to RT enhancement studied in this …

A Review Of Methodologies Applied For Determining Particulate Matter Characterization In Urban Regions, Garrett F. Diehl

University Honors Theses

This is a literature review on previous research conducted on particulate matter deposited on urban vegetation. This was accomplished by searching six databases, that uncovered 37 peer-reviewed journal articles. The main objective of this review is to present the methodology and findings of the articles analyzed to demonstrate how research in this area of study is being conducted. The findings show that there are variations in the literature and that many variables are not being incorporated into the methods and analyses of particulate matter found on urban vegetation. Understanding how different studies have analyzed particulate matter found on urban vegetation …

Optimized Xanthene-Based Probes For Pancreatic Cancer Imaging, Ian Ruramai Munhenzva

Dissertations and Theses

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the deadliest human malignancies with an extremely poor 5-year survival rate of below 5%. Surgical resection is the most effective treatment of choice because chemotherapy and radiation therapy do not improve life expectancy. Residual tumor after PDAC surgery is common due to a lack of PDAC targeted intraoperative contrast agents to confirm clear margins.

Fluorescence imaging has the potential to improve surgery outcome and PDAC patients' survival rate via the use of highly PDAC-specific molecular probes to facilitate tumor identification. This thesis describes the application of a focused library of benzoxanthene fluorophores for …