Other Chemistry Commons^™

Student Familiarity With The Periodic Table Of The Elements: Results From Cued-Recall And Eye-Tracking Assessments On Memory, Victor A. Okuo

Theses and Dissertations--Chemistry

Learning element symbol–name associations and the spatial organization of elements on the periodic table is a foundational step in learning chemistry, supporting later understanding of chemical formulas, equations, bonding, and stoichiometry. Although students often rely on memorization strategies to learn periodic table content, this task is challenging due to the large number of elements and the apparent ambiguity in matching some element symbols to their names.

This study explores students’ recall of element names when given element symbols as cues and their knowledge of element locations on the periodic table when given element names as cues. The study also examines …

Microfiltration Membrane Pore Functionalization With Primary And Quaternary Amines For Pfas Remediation: Capture, Regeneration, And Reuse, Sam Thompson, Angela Gutierrez, Jennifer Bukowski, Dibakar Bhattacharyya

UK CARES Faculty Publications

The widespread production and use of multi-fluorinated carbon-based substances for a variety of purposes has contributed to the contamination of the global water supply in recent decades. Conventional wastewater treatment can reduce contaminants to acceptable levels, but the concen- trated retentate stream is still a burden to the environment. A selective anion-exchange membrane capable of capture and controlled release could further concentrate necessary contaminants, mak- ing their eventual degradation or long-term storage easier. To this end, commercial microfiltration membranes were modified using pore functionalization to incorporate an anion-exchange moiety within the membrane matrix. This functionalization was performed with primary and …

Response To Replication Stress And Maintenance Of Genome Stability By Wrn, The Werner Syndrome Protein, David K. Orren, Amrita Machwe

Markey Cancer Center Faculty Publications

Werner syndrome (WS) is an autosomal recessive disease caused by loss of function of WRN. WS is a segmental progeroid disease and shows early onset or increased frequency of many characteristics of normal aging. WRN possesses helicase, annealing, strand exchange, and exonuclease activities and acts on a variety of DNA substrates, even complex replication and re- combination intermediates. Here, we review the genetics, biochemistry, and probably physiological functions of the WRN protein. Although its precise role is unclear, evidence suggests WRN plays a role in pathways that respond to replication stress and maintain genome stability particularly in telomeric regions.

A Single Hydrogen Bond That Tunes Flavin Redox Reactivity And Activates It For Modification, Debarati Das, Anne-Frances Miller

Markey Cancer Center Faculty Publications

Electron bifurcation produces high-energy products based on less energetic reagents. This feat enables biological systems to exploit abundant mediocre fuel to drive vital but demanding reactions, including nitrogen fixation and CO₂ capture. Thus, there is great interest in understanding principles that can be portable to man-made devices. Bifurcating electron transfer flavoproteins (Bf ETFs) employ two flavins with contrasting reactivities to acquire pairs of electrons from a modest reductant, NADH. The bifurcating flavin then dispatches the electrons individually to a high and a low reduction midpoint potential (E°) acceptor, the latter of which captures most of the energy. Maximum efficiency …

Myeloid-Derived Suppressor Cell Mitochondrial Fitness Governs Chemotherapeutic Efficacy In Hematologic Malignancies, Saeed Daneshmandi, Jee Eun Choi, Qi Yan, Cameron R. Macdonald, Manu Pandey, Mounika Goruganthu, Nathan Roberts, Prashant K. Singh, Richard M. Higashi, Andrew N. Lane, Teresa W-M Fan, Jianmin Wang, Philip L. Mccarthy, Elizabeth A. Repasky, Hemn Mohammadpour

Markey Cancer Center Faculty Publications

Myeloid derived suppressor cells (MDSCs) are key regulators of immune responses and correlate with poor outcomes in hematologic malignancies. Here, we identify that MDSC mitochondrial fitness controls the efficacy of doxorubicin chemotherapy in a preclinical lymphoma model. Mechanistically, we show that triggering STAT3 signaling via β2-adrenergic receptor (β2-AR) activation leads to improved MDSC function through metabolic reprogram- ing, marked by sustained mitochondrial respiration and higher ATP generation which reduces AMPK signaling, altering energy metabolism. Furthermore, induced STAT3 signaling in MDSCs enhances glutamine consumption via the TCA cycle. Metabolized glutamine generates itaconate which downregulates mitochondrial reactive oxygen species via regulation of …

Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko

UK CARES Faculty Publications

The scalable commercialization of organic electronics wherein p-conjugated polymers serve as the semiconductors hinges on precise control of the material electronic, redox, optical, and mechanical properties, which are each highly influenced by local and long-range morphology. Here, we undertake atomistic molecular dynamics (MD) simulations at three temperatures (150 K, 300 K, and 400 K) to assess the morphological and mechanical response of bulk poly(3-hexylthiophene) (P3HT), a representative homopolymer of interest as an organic semiconductor (OS). As P3HT is a semicrystalline polymer, we characterize mechanical properties for both amorphous and crystalline P3HT models to derive insights into structure–property relationships, including Young’s …

Extended Conformations Of Bifurcating Electron Transfer Flavoprotein Constitute Up To Half The Population, Possibly Mediating Conformational Change, Sharique A. Khan, Alan Hicks, Wellington C. Leite, James Byrnes, Biswajit Gorai, Maria-Andrea Mroginski, Hugh O'Neill, Anne-Francis Miller

Markey Cancer Center Faculty Publications

Electron transfer bifurcation enables biological systems to drive unfavourable (endergonic) electron transfer by coupling it to favourable (exergonic) transfer of a second electron. In electron transfer flavoproteins (ETFs), a domain-scale conformational change is believed to sever the favourable pathway after a single electron has used it, thereby preventing the energy dissipation that would accompany exergonic transfer of the second electron. To understand the conformation change that participates in turnover, we have deployed small-angle neutron scattering (SANS) and computational techniques to characterize the bifurcating ETF from Acidaminococcus fermentans (AfeETF). SANS data reveal an overall radius of gyration (Rg) of 30.1 ± …

Perfluorooctanesulfonic Acid Exposure Leads To Downregulation Of 3-Hydroxy-3-Methylglutaryl-Coa Synthase 2 Expression And Upregulation Of Markers Associated With Intestinal Carcinogenesis In Mouse Intestinal Tissues, Josiane Weber Tessmann, Pan Deng, Jerika Durham, Chang Li, Moumita Banerjee, Qingding Wang, Ryan A. Goettl, Daheng He, Chi Wang, Eun Y. Lee, B. Mark Evers, Bernhard Hennig, Yekaterina Y. Zaytseva

Markey Cancer Center Faculty Publications

Perfluorooctanesulfonic acid (PFOS) is a widely recognized environment pollutant known for its high bio- accumulation potential and a long elimination half-life. Several studies have shown that PFOS can alter multiple biological pathways and negatively affect human health. Considering the direct exposure to the gastrointestinal (GI) tract to environmental pollutants, PFOS can potentially disrupt intestinal homeostasis. However, there is limited knowledge about the effect of PFOS exposure on normal intestinal tissues, and its contribution to GI- associated diseases remains to be determined. In this study, we examined the effect of PFOS exposure on the gene expression profile of intestinal tissues of …

Fundamental Studies Of Optical Properties And Electrocatalytic Properties Of Low Dimensional Nanomaterials Carbon Nano Dots And 2d Transition Metal Dichalcogenides, Nadeesha Kothalawala

Theses and Dissertations--Chemistry

Low dimensional nanomaterials are widely used in a variety of applications such as opto-electronics, energy production and storage, and bio-medical applications due to their unique optical, catalytic, electronic, and mechanical properties. Most of the nanomaterials offer a plethora of modifications in their structure, composition, morphology, and dimensionality that can lead to the manipulation of their physiochemical properties. This dissertation presents insight into two types of compelling nanomaterials: carbon nanodots (CND) and transition metal dichalcogenides (TMD), investigating their optical and electrocatalytic properties respectively.

Carbon nanodots (CND) are a promising class of photoluminescent nanomaterials that hold a significant potential in many optoelectronic …

Oxidative Damage To Brain Cells Underlies: (I) Resistance To Radiation And Increased Tumor Cell Growth In Glioblastoma; (Ii) Apoe Allele Status And Pentose Phosphate Pathway Proteins In Alzheimer Disease Mouse Models, Nicole Rummel

Theses and Dissertations--Chemistry

Oxidative phosphorylation occurs within the inner mitochondrial membrane producing ATP for the cell’s energy needs. The Electron Transport Chain carries out the transfer of electrons from electron carriers through a series of proteins to form a proton gradient across the inner mitochondrial membrane. This gradient acts as the energy source needed to put a phosphate onto ADP and form ATP. With the large amounts of free electrons and oxygen within the mitochondria, an inevitable by-product of free radicals in the form of superoxide are produced. Superoxide (O^-̇₂) is a reactive radical that can react further to …

The Development Of Colorimetric Assays To Determine The Identity And Frequency Of Specific Nucleobases In Dna Oligomers, Elizabeth Marie Thomas

Theses and Dissertations--Chemistry

Colorimetric methods combined with color-changing chemical probes are widely used as simple yet effective tools for identifying and quantifying a wide variety of molecules in solution. For nucleic acids (DNA and RNA), perhaps the most commonly used colorimetric probe is potassium permanganate, which can be used to identify single-stranded pyrimidines (thymine and cytosine) in polymers. Unfortunately, permanganate is not an effective probe for identifying purines (adenine and guanine), especially in the presence of the more reactive pyrimidines. Therefore, robust methods for discriminating between the purines remain elusive, thereby creating a barrier toward developing more complex colorimetric applications. In this dissertation, …

Investigation Into The Competitive Partitioning Of Dissociated H2 And D2 On Activated Fischer-Tropsch Catalysts, Wilson D. Shafer

Theses and Dissertations--Chemistry

The Fischer-Tropsch process, discovered in the early to mid-1920s, still has researchers disputing the C₁ monomer, and the rate-determining step. A tremendous amount of work, over the years, has focused on how hydrogen plays a role in the pseudo-polymerization of chain initiation and propagation, in an attempt to reveal the mechanism. These investigations attempted to elucidate the debated issues through studying the kinetic isotopic effect (KIE) for CO hydrogenation by switching the syngas from CO/H₂ to CO/D₂ during a steady-state period. Applying this switching step could result in a deviation in the rate of CO hydrogenation, indicating …

Electron And Ion Spectroscopy Of Metal Hydrocarbon Complexes, Sudesh Kumari

Theses and Dissertations--Chemistry

Metal-hydrocarbon complexes were prepared in a laser-vaporization molecular beam source and studied by single-photon zero electron kinetic energy (ZEKE) and mass-analyzed threshold ionization (MATI) spectroscopy. The ionization energies and vibrational frequencies of the metal complexes were measured from the ZEKE and MATI spectra. Metal-ligand bonding and low-lying electronic states of the neutral and ionized complexes were analyzed by combining the spectroscopic measurements with quantum chemical calculations and spectral simulations.

In this dissertation, the metal complexes of mesitylene, aniline, cyclooctatetraene, benzene, ethene, and propene were studied. For each complex, different effects from metal coordination have been identified. Although metal-bis(mesitylene) sandwich complexes …

Organic Thin-Film Transistors And Tips-Pentacene, Zachary Stewart

Lewis Honors College Capstone Collection

TIPS-Pentacene, an organic semiconductor characterized by its good electronic properties, solubility, and stability, is used primarily in organic thin-film transistors (OTFT). This research seeks to create an OTFT by crafting a stencil, depositing the source and drain onto a substrate’s surface, and processing TIPS-Pentacene onto the channel between them. In addition, if time permits, the electronic properties of several OTFTs will be compared to determine how to optimize their production.

Oxidative Damage To Dna In Alzheimer's Disease, Sony Soman

Theses and Dissertations--Chemistry

Previous studies from our laboratory and others show a significant increase in levels of both nuclear and mitochondrial DNA and RNA oxidation in vulnerable brain regions in the progression of Alzheimer’s disease (AD). Although total DNA oxidation is increased in AD it remains unclear whether oxidative damage is widespread throughout the genome or is concentrated to specific genes. To test the hypothesis that specific genes are more highly oxidized in the progression of AD, we propose to quantify the percent oxidative damage in genes coding for proteins shown to be altered in the progression of AD using quantitative/real-time polymerase chain …

Application Of Pyrolysis-Gc/Ms To The Study Of Biomass And Biomass Constituents, Anne E. Ware

Theses and Dissertations--Chemistry

Fast pyrolysis, the rapid thermal decomposition of organic material in the absence of oxygen, is a process that can be used to convert biomass into liquid fuels and chemicals. When performed at the micro-scale, pyrolysis is useful for characterizing biomass structure, as well as determining the pyrolysis products that can be generated from specific biomass feedstocks. Indeed, microscale pyrolysis coupled with on-line analysis of the pyrolysis vapors by GC/MS, so-called pyrolysis-GC/MS (Py-GC/MS), is a technique that can be used to characterize the structure and composition of the various components of lignocellulosic and microalgal biomass based on their pyrolysate distributions. Pyrolysates …