Chemistry Commons^™

Agnotology Of The E-Cigarette Industry: How The E-Cigarette Industry Continues The Tobacco Industry's Legacy Of Creating Controversy And Confusion Within The Scientific Community And The General Population, Calvin Lewis

University Honors Theses

The purpose of this paper is to determine the extent to which the e-cigarette industry follows in the footsteps of the tobacco industry's attempts to disrupt science and cause controversy. Four tactics are described that the tobacco industry uses to disrupt science: funding research that is designed to show results that support their position, criticizing and suppressing research that goes against their position, changing risk assessment and scientific research standards to fit their aims, and spreading data created by their interest groups to politicians and the nonacademic press. Evidence is found to show that both the tobacco industry and e-cigarette …

Toxicity Of Waterpipe Tobacco Smoking: The Role Of Flavors, Sweeteners, Humectants, And Charcoal, Nada O F Kassem, Robert M. Strongin, Andrea M. Stroup, Marielle C. Brinkman, Ahmad El-Hellani, Hanno C. Erythropel, Arash Etemadi, Maciej L. Goniewicz, Eleanore G. Hansen, Noura O. Kassem, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

Waterpipe tobacco (WPT) smoking is a public health concern, particularly among youth and young adults. The global spread of WPT use has surged since the introduction of pre-packaged flavored and sweetened WPT, which is widely marketed as a safer tobacco alternative. Besides flavorants and sugars, WPT additives include humectants, which enhance the moisture and sweetness of WPT, act as solvents for flavors, and impart smoothness to the smoke, thus increasing appeal to users. In the United States (U.S.), unlike cigarette tobacco flavoring (with the exception of menthol), there is no FDA product standard or policy in place prohibiting sales of …

Synthesis And Computational Studies Of Α- And Δ-Substituted Macrocyclic Europium And Ytterbium Complexes, Delainey Amara Winder

Dissertations and Theses

The uses of macrocyclic lanthanide complexes are vast, with many targeted MRI contrast agents at the forefront of the field. Many of these are ParaCEST agents, which require exchangeable protons accessible on the macrocycle and the slow exchange of coordinated water molecules. The substitution at both the α- and δ-carbon on the amide pendant arm of these macrocyclic lanthanide complexes can lock bulky groups on the δ-carbon to a pseudo-axial position. When the α- and δ-carbons have the same chirality, the bulky group will be pseudo-equatorial, and when the chirality is opposed, the bulky group will be pseudo-axial. By performing …

A Comparison Of Structure, Bonding And Non-Covalent Interactions Of Aryl Halide And Diarylhalonium Halogen-Bond Donors, Nicole Javaly, Theresa M. Mccormick, David R. Stuart

Chemistry Faculty Publications and Presentations

Halogen bonding permeates many areas of chemistry. A wide range of halogen-bond donors including neutral, cationic, monovalent, and hypervalent have been developed and studied. In this work we used density functional theory (DFT), natural bond orbital (NBO) theory, and quantum theory of atoms in molecules (QTAIM) to analyze aryl halogen-bond donors that are neutral, cationic, monovalent and hypervalent and in each series we include the halogens Cl, Br, I, and At. Within this diverse set of halogen-bond donors, we have found trends that relate halogen bond length with the van der Waals radii of the halogen and the non-covalent or …

Mechanistic Rationale For Ketene Formation During Dabbing And Vaping, Kaelas R. Munger, Killian M. Anreise, Robert P. Jensen, David H. Peyton, Robert M. Strongin

Chemistry Faculty Publications and Presentations

Ketene is one of the most toxic vaping emissions identified to date. However, its high reactivity renders it relatively challenging to identify. In addition, certain theoretical studies have shown that realistic vaping temperature settings may betoo low to produce ketene. Each of these issues is addressed herein. First, an isotopically labeled acetate precursor is used for the identification of ketene with enhanced rigor in vaped aerosols. Second, discrepancies between theoretical and experimental findings are explained by accounting for the effects of aerobic (experimental) versus anaerobic (simulated and theoretical) pyrolysis conditions. This finding is also relevant to explaining the relatively low-temperature …

Complete Genome Sequence Of Strain Jm503a, A Genetically Tractable Dental Abscess Clinical Isolate, Dustin L. Higashi, Anh Nguyen, Hua Qin, Christina Borland, Elizabeth A. Palmer, Nicolas Biais, Jens Kreth, Justin Merritt

Chemistry Faculty Publications and Presentations

Parvimonas micra is a pathobiont of humans that is often found in abundance at sites of mucosal inflammation as well as within malignant tumors. Here, we report the complete genome sequence of P. micra strain JM503A, which is a genetically tractable clinical isolate derived from a human odontogenic abscess specimen.

Dft Based Modeling Of The Heavy Atom Effect In Triplet Photosensitizers: From Fundamental Mechanics To Rational Design, Bret Andrew Steinkamp

Dissertations and Theses

Photochemistry is the study of how light interacts with molecules and includes both the absorption and release of light. This document focuses on triplet photosensitizers -- molecules that utilize the excited triplet state -- for a variety of applications including photodynamic therapy and photocatalysis. There are many factors that influence the design of triplet photosensitizers; in this work, we have developed and used a methodology for the rational design of triplet photosensitizers based on an approximation of the heavy atom effect (HAE) from density functional theory calculations and the experimentally measured singlet oxygen quantum yield (Ф_Δ).

As excited …

Moss Biomonitoring Of Lead Emissions From Hillsboro Airport, Daria Kolpakov

University Honors Theses

The objective of this experiment was to use biomonitoring as a method to determine lead concentration levels around Hillsboro Airport in Hillsboro, Oregon. Twenty-two samples were collected within a 2 km radius around Hillsboro Airport using a randomized sampling strategy. The concentrations of lead within the samples were determined using ICP-MS. The average lead concentration was (2.8 ± 5.0) mg/kg with a peak value of 21.6 mg/kg 0.57 km from Hillsboro Airport. As the average lead concentration was substantially skewed, Hillsboro Airport is likely to be the source of the lead increase.

Efficient And Chemoselective Access To Highly Functionalized Arenes By C-H Deprotonative Generation Of Aryne Intermediates, Bryan Edward Metze

Dissertations and Theses

Arenes are a ubiquitous structural motif occurring in numerous organic pharmaceuticals, agrochemicals, secondary metabolites, and functional materials. As such, studies on the characterization, functionalization, and properties of arenes have been a central pillar of organic chemistry since its inception. Early methods to synthesize complex benzenoid rings focused on ring functionalization rather than ring construction due to the high accessibility of very simple arenes and the wide range of aromatic substitution reactions discovered in the late 19th century. As the importance of arenes was recognized more methods of building complex arenes emerged. Both classical and modern approaches are still somewhat limited, …

A Review Of The Toxicity Of Ingredients In E-Cigarettes, Including Those Ingredients Having The Fda's "Generally Recognized As Safe (Gras)" Regulatory Status For Use In Food., Nada O F Kassem, Robert M. Strongin, Andrea M. Stroup, Marielle C. Brinkman, Ahmad El-Hellani, Hanno C. Erythropel, Arash Etemadi, Vernat Exil, David H. Peyton, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

Some firms and marketers of electronic cigarettes (e-cigarettes; a type of electronic nicotine delivery system (ENDS)) and refill liquids (e-liquids) have made claims about the safety of ingredients used in their products based on the term "GRAS or Generally Recognized As Safe" (GRAS). However, GRAS is a provision within the definition of a food additive under section 201(s) (21 U.S.C. 321(s)) of the U.S. Federal Food Drug and Cosmetic Act (FD&C Act). Food additives and GRAS substances are by the FD&C Act definition intended for use in food, thus safety is based on oral consumption; the term GRAS cannot serve …

The Lewis Acidity Of Imidazole-Derived Diaryliodonium Zwitterions, Cyrus Rose

University Honors Theses

Diaryliodonium salts can be used as effective aryl-transfer agents in reactions to form novel molecules with diverse applications including pharmaceuticals and agrochemicals without using harsh reaction conditions and transition metal reagents. In recent years, interest in the applications of the Lewis acidity of iodonium ion catalysts has increased. Despite this, the quantification of the Lewis acidities of diaryliodonium salts are scarce. Even rarer, there has not been much study into the Lewis acidities of zwitterionic diaryliodonium salts. For zwitterions, there is no counter anion that would come into consideration in regard to its Lewis acidity. To expand the understanding of …

The Effect Of Metabolic Modulators On The Rate Of Steady State Water Exchange In S. Cerevisiae Grown In Chemostat Bioreactors, Samantha Mumford, Mark Woods, Johnathan Dutra

Student Research Symposium

Water transport across the lipid bilayer due to osmotic stress causes a change in intracellular volume over time. At isotonic equilibrium there is no change in cell volume and yet water exchange does not stop. Water molecules continue to exchange rapidly with those of the extracellular space. The rate constant for steady state water efflux (k_io) can be measured using contrast enhanced magnetic resonance (MR) and the two-site exchange (2SX) model. k_io is known to correlate with the cellular energy molecule ATP making it a probable biomarker for metabolic diseases such as cancer. Measurements of k …

Method Validation Of Metals In Environmental Soil Samples, Sofia Deangelis, Nana Nguyen

Student Research Symposium

Vehicles are a major source of metal accumulation in terrestrial environments. Green infrastructure, such as bioswales, has been implemented as a way to mitigate this damage. However, there is a limited understanding of the processes that occur in these bioswales as few go back after implementation to identify areas in the bioswale with accumulation of pollutants. Inductively coupled mass spectrometry (ICP-MS) has the potential to be used in this type of study due to the machine’s high sensitivity and selectivity. However complications can arise while using the ICP-MS to characterize complex environmental samples. This study seeks to optimize microwave assisted …

Competing Supramolecular Forces: Boron Coordination Vs Π-Π Stacking, Sidhaesh A. Agarwal, Gonzalo Campillo-Alvarado, Nicholas Lutz, Jesus Daniel Loya, Eric W. Reinheimer

Student Research Symposium

This study explores the impact of fluorination levels in azopyridine Lewis bases on their ability to direct the formation of B←N coordination adducts or cocrystals with phenylboronic ester. We hypothesize that the degree of fluorination can be used as a tool to control the outcome of supramolecular bonding competition, thus influencing complex self-assembly.

A series of azopyridines with varying degrees of fluorination were synthesized and reacted with phenylboronic ester. Their structures were analyzed using Hartree-Fock calculations, Hirshfeld surface analyses, and single crystal X-ray diffraction to assess the impact of fluorination on supramolecular interactions.

The study reveals that azopyridines with up …

Multiscale Variability Of Heavy Metals In A Western U.S. Snowpack, Kelsey Hefner

Student Research Symposium

Natural and anthropogenically sourced particulates are deposited from the atmosphere to landscapes via dry and wet deposition, making frozen winter snowpack a natural archive of atmospheric elemental composition. Wildfires in the Western United States are increasing in extent, duration, and severity, especially in alpine regions. Severe fires remove forest canopy and can impact how atmospheric elements are dispersed and stored across snow-dominated watersheds. We evaluated Al, V, Cr, Mn, Ni, Cu, As, Zn, Se, Mo, Cd, and Pb concentrations in 394 winter snow core samples. We collected samples in 2019 and 2020 from a chronosequence of eight forests that burned …

Computationally Assisted Mechanistic Analysis Of The Protonolysis Of A Pt–Me Bond, Clement Dasilva

Student Research Symposium

Mechanistic study of the protonolysis of (cod)PtMe2 could give insight into the activation of C-H bonds by platinum because it is the microscopic reverse reaction. Two possible mechanisms for the protonolysis of dimethyl platinum complexes have been proposed, with experimental and computational data supporting the single step, SE2, over the multistep, SE(ox) mechanism. New experimental work from our group supports a multi-step mechanism with multiple acid molecules. In this work, the SE2 mechanism as well as a proposed SE(ox) mechanism were computationally modeled with a single equivalent of acid, TFAH, and two equivalents using density functional theory. The modeled pathways …

Photocathodes From Aerobic Oxidation Of Tellurorhodamines, Amelia Jellison

Student Research Symposium

Contemporary dye-sensitized solar cells are far less efficient than silicon solar panels, therefore this project seeks to develop an improved dye sensitized photocathode. Tellurorhodamine dyes, including mesityl derivatives and tellurium black, have been chosen to increase efficiency through increased light harvesting. The photophysical and electrochemical properties of tellurorhodamines with varying structures are analyzed to quantify its efficiency to serve as a dye sensitized photo cathode. Dyes undergo aerobic oxidation facilitated by light, the absorption profile is obtained before and after. Mesityl derivatives are known to experience significant red-shifting following aerobic oxidation. At its base oxidation state, tellurium black experiences an …

Exploring The Potential Of Α-Aryl Substitution Of Gddota To Address Challenges Associated With Mri Contrast Agents., Charlene I. Kupara

Student Research Symposium

Gadolinium chelates have found widespread application as contrast agents in Magnetic Resonance Imaging (MRI) a cornerstone in modern medical diagnostics. In recent years two significant challenges have emerged to the use of Gd³⁺ chelates in MRI:

• The safety of these Gd³⁺-based agents, specifically related to the possible in vivo release of Gd³⁺.
• The environmental impact of anthropogenic Gd³⁺ pollution of surface waters arising from using contrast agents.

The escalating reports of Gd³⁺ presence in environmental matrices, and its adverse effects on marine life and human health, necessitate urgent intervention to mitigate consequential environmental …

Chemical And Physiological Interactions Between E-Liquid Constituents: Cause For Concern?, Robert M. Strongin, Eva Sharma, Hanno C. Erythropel, Nada O F Kassem, Alexandra Noël, D H. Peyton, Irfan Rahman

Chemistry Faculty Publications and Presentations

Studies of Electronic Nicotine Delivery Systems (ENDS) toxicity have largely focused on individual components such as flavour additives, base e-liquid ingredients (propylene glycol, glycerol), device characteristics (eg, model, components, wattage), use behaviour, etc. However, vaping involves inhalation of chemical mixtures and interactions between compounds can occur that can lead to different toxicities than toxicity of the individual components. Methods based on the additive toxicity of individual chemical components to estimate the health risks of complex mixtures can result in the overestimation or underestimation of exposure risks, since interactions between components are under-investigated. In the case of ENDS, the potential of …

Comparison Of Emissions Across Tobacco Products: A Slippery Slope In Tobacco Control, Ahmad El-Hellani, Ayomipo Adeniji, Hanno C. Erythropel, Thomas Lamb, Qixin Wang, Vladimir Mikheev, Robert Strongin, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

In this narrative review, we highlight the challenges of comparing emissions from different tobacco products under controlled laboratory settings (using smoking/ vaping machines). We focus on tobacco products that generate inhalable smoke or aerosol, such as cigarettes, cigars, hookah, electronic cigarettes, and heated tobacco products. We discuss challenges associated with sample generation including variability of smoking/vaping machines, lack of standardized adaptors that connect smoking/vaping machines to different tobacco products, puffing protocols that are not representative of actual use, and sample generation session length (minutes or number of puffs) that depends on product characteristics. We also discuss the challenges of physically …

Dynamic Fibrillar Assembly Of Αb-Crystallin Induced By Perturbation Of The Conserved Nt-Ixi Motif Resolved By Cryo-Em, Russell Mcfarland, Steve Reichow

Chemistry Faculty Publications and Presentations

αB-crystallin is an archetypical member of the small heat-shock proteins (sHSPs) vital for cellular proteostasis and mitigating protein misfolding diseases. Gaining insights into the principles defining their molecular organization and chaperone function have been hindered by intrinsic dynamic properties and limited high-resolution structural analysis. To disentangle the mechanistic underpinnings of these dynamical properties, we mutated a conserved IXI-motif located within the N-terminal (NT) domain of human αB-crystallin. This resulted in a profound structural transformation, from highly polydispersed caged-like native assemblies into a comparatively well-ordered helical fibril state amenable to high-resolution cryo-EM analysis. The reversible nature of the induced fibrils facilitated …

Preliminary Reactions For Do3mbn Ester Design Of Experiments With A Separation Procedure For Do2mbn Ester And Do3mbn Ester Ligand, Cerys A. Easton

University Honors Theses

The ratio of products resulting from a reaction of cyclen (1,4,7,10-tetraazacyclododecane) and benzyl (S)-2-bromopropanoate substituent arm is analyzed in three polar aprotic solvents at varying concentrations of cyclen and temperatures. This is for a future design of experiments procedure to determine the optimal experimental conditions for selective DO3MBn ester production without the use of a protecting group. It was found that the reaction completion time is less than 24 hours at reaction temperatures at or above 50 °C and less than 3 days for reaction temperatures at 30 °C regardless of the cyclen concentrations or equivalents of substituent …

Using Flipped Classroom Modules To Facilitate Higher Order Learning In Undergraduate Organic Chemistry, Lauren R. Holloway, Tabitha Miller, Bryce Da Camara, Paul M. Bogie, Briana L. Hickey, Jack Barbera, Angie L. Lopez, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

In an ongoing effort to incorporate active learning and promote higher order learning outcomes in undergraduate organic chemistry, a hybrid (“flipped”) classroom structure has been used to facilitate a series of collaborative activities in the first two courses of the lower division organic chemistry sequence. An observational study of seven classes over a five-year period reveals there is a strong correlation between performance on the in-class activities and performance on the final exam across all classes; however, a significant number of students in these courses continue to struggle on both the in-class activities and final exam. The Activity Engagement Survey …

Dna-Based Assay For Calorimetric Determination Of Protein Concentrations In Pure Or Mixed Solutions, Matthew W. Eskew, Patrick Reardon, Albert S. Benight

Chemistry Faculty Publications and Presentations

It was recently reported that values of the transition heat capacities, as measured by differential scanning calorimetry, for two globular proteins and a short DNA hairpin in NaCl buffer are essentially equivalent, at equal concentrations (mg/mL). To validate the broad applicability of this phenomenon, additional evidence for this equivalence is presented that reveals it does not depend on DNA sequence, buffer salt, or transition temperature (Tm). Based on the equivalence of transition heat capacities, a calorimetric method was devised to determine protein concentrations in pure and complex solutions. The scheme uses direct comparisons between the thermodynamic stability of a short …

Limonene Enantiomeric Ratios From Anthropogenic And Biogenic Emission Sources, Shan Gu, Wentai Luo, Avisa Charmchi, Kevin J. Mcwhirter, Todd Rosenstiel, James F. Pankow

Chemistry Faculty Publications and Presentations

Emissions from volatile chemical products (VCPs) have been identified as contributors to air quality degradation in urban areas. Limonene can be a tracer compound for VCPs containing fragrances in densely populated regions, but limonene is also emitted from conifers that are planted in urban areas. This creates challenges for using limonene to estimate VCP emissions. In this study, the −/+ enantiomeric ratios of limonene from VCP and conifer emission sources were quantified to evaluate if this measurement could be used to aid in source apportionment and emission inventory development. Samples were analyzed using a gas chromatograph equipped with a chiral …

The Α-Crystallin Chaperones Undergo A Quasi-Ordered Co-Aggregation Process In Response To Saturating Client Interaction, Kirsten Lampi, Adam P. Miller, Susan E. O'Neill, Steve L. Reichow

Chemistry Faculty Publications and Presentations

Small heat shock proteins (sHSPs) are ATP-independent chaperones vital to cellular proteostasis, preventing protein aggregation events linked to various human diseases including cataract. The α-crystallins, αA-crystallin (αAc) and αB-crystallin (αBc), represent archetypal sHSPs that exhibit complex polydispersed oligomeric assemblies and rapid subunit exchange dynamics. Yet, our understanding of how this plasticity contributes to chaperone function remains poorly understood. This study investigates structural changes in αAc and αBc during client sequestration under varying degree of chaperone saturation. Using biochemical and biophysical analyses combined with single-particle electron microscopy (EM), we examined αAc and αBc in their apo-states and at various stages of …

An Efficient And Chemoselective Method To Generate Arynes, Bryan Metze, Riley A. Roberts, Aleksandra Nilova, David R. Stuart

Chemistry Faculty Publications and Presentations

Arynes hold immense potential as reactive intermediates in organic synthesis as they engage in a diverse range of mechanistically distinct chemical reactions. However, the poor functional group compatibility of generating arynes or their precursors has stymied their widespread use. Here, we show that generating arynes by deprotonation of an arene and elimination of an “onium” leaving group is mild, efficient and broad in scope. This is achieved by using aryl(TMP)iodonium salts (TMP = 2,4,6-trimethoxyphenyl) as the aryne precursor and potassium phosphate as the base, and a range of arynophiles are compatible. Additionally, we have performed the first quantitative analysis of …

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 …

Cfa-Treated Mice Induce Hyperalgesia In Healthy Mice Via An Olfactory Mechanism, Yangmiao Zhang, Wentai Luo, Maryt M. Heinricher, Andrey E. Ryabinin

Chemistry Faculty Publications and Presentations

Background

Social interactions with subjects experiencing pain can increase nociceptive sensitivity in observers, even without direct physical contact. In previous experiments, extended indirect exposure to soiled bedding from mice with alcohol withdrawal-related hyperalgesia enhanced nociception in their conspecifics. This finding suggested that olfactory cues could be sufficient for nociceptive hypersensitivity in otherwise untreated animals (also known as “bystanders”).

Aim

The current study addressed this possibility using an inflammation-based hyperalgesia model and long- and short-term exposure paradigms in C57BL/6J mice.

Materials & Method

Adult male and female mice received intraplantar injection of complete Freund's adjuvant (CFA) and were used as stimulus …

Calorimetric Analysis Using Dna Thermal Stability To Determine Protein Concentration, Matthew W. Eskew, Patrick Reardon, Albert S. Benight

Chemistry Faculty Publications and Presentations

It was recently reported for two globular proteins and a short DNA hairpin in NaCl buffer that values of the transition heat capacities, Cp,DNA and Cp,PRO for equal concentrations (mg/mL) of DNA and proteins, are essentially equivalent (differ by less than 1%). Additional evidence for this equivalence is presented that reveals this phenomenon does not depend on DNA sequence, buffer salt, or Tm. Sequences of two DNA hairpins were designed to confer a near 20°C difference in their Tm’s. For the molecules, in NaCl and CsCl buffer the evaluated Cp,PRO and C …