Physical Sciences and Mathematics Commons^™

Swelling Studies Of Poly(Ionic Liquids) In Different Solvents And Salt Solutions, Pierson Perdue, Ali Alshaikh, Creighton Baltier, Jason E. Bara, Sourav Chatterjee

Scholars Week

Poly(ionic liquid)s (PILs) represented a special class of polymers, which comprised of a polymeric backbone and ionic liquids (ILs) species in each monomeric repeating units. PILs has properties that combined the properties of ionic liquids (ILs) (i.e., high conductivity, better thermal and chemical stability, and tailor-made functionality) with the intrinsic properties of polymer (i.e., mechanical stability). This synergistic property makes PILs a good candidate for various applications such as stable-ion conductors, membranes for gas separations and sorbents. In the past, it was shown that PILs are capable of swelling when dissolved in different ILs but there are few literature reported …

Synthesis And Characterization Of Semi-Interpenetrating And Double Networks Of Sulfonimide- And Imidazolium-Containing Poly(Ionic Liquids), Jeremiah Coughlon, Seth Taylor, Jason Bara, Kevin Miller, Sourav Chatterjee

Scholars Week

In recent years, there has been increased research interest in creating electrically conductive polymer membranes with materials that are widely available and environmentally safe. Herein, we report how polymeric membranes comprised of unique combinations of ionenes and poly(ionic liquids), including a recently developed sulfonimide- and imidazolium-containing methacryloxy-based monomer, were produced via UV photopolymerization. These membranes were specifically tailored to exhibit both ionic conductivity and an affinity for carbon dioxide, which are both crucial characteristics in such applications as electron transport in lithium-ion batteries and gas sorbency in separation techniques. Monomers, such as the aforementioned methacryloxy-based ionic liquid (IL) and C4VIm, …

Synthesis And Properties Of Bio-Based 3d Printable Resins, Cameron Woods, Seth Taylor, Jeremiah Coughlon, Turner Perdue, Sourav Chatterjee, Jason E. Bara

Scholars Week

A photopolymer resin is a monomer that, when introduced to light of a certain wavelength, starts to polymerize into a solid. This has become a growing part of the 3D printing industry. There have been many advancements in the field of 3D printing, however, a lot of these resins are not environmentally friendly and even harmful if not handled in the correct manner. Plant based resins are becoming more and more popular because of their biodegradability and for the possibility of using renewable resources. Glycerol is a plant-based compound that is produced in excess in industry. Glycerol obtained from bioethanol …

Physiochemical Properties Of Urethane-Containing Ionic Liquids And Ionenes From A Non-Isocyanate Synthetic Approach, George Timmermann

Scholars Week

Ionic polymers that are designed to contain ionic liquids (ILs) in their backbones have been shown to exhibit a high degree of variability through changing the type of ionic character and the location of the ionic region within the molecule. This large amount of variability in both the structure and characteristics of ILs allows researchers to design task-specific ionic polymers and ILs for a variety of applications including gas separation membranes and solid polymer electrolytes. The synthesis of a specific class of ILs and ionenes through the incorporation of urethane groups with imidazolium rings by reacting carbonyl diimidazole with various …

Temporal Changes And Possible Sources Of Dissolved Calcium Levels In Stream, River, And Lake Waters In Western Kentucky, Kelsie Meystedt

Scholars Week

ABSTRACT

Zebra Mussels (Dreissena polymorpha) are an exotic and invasive mollusk that spread extensively over various rivers and lakes in the United States. These mussels are known for being notorious in their “biofouling” capabilities, costing the U.S. government billions of dollars in removal operations. Recently, zebra mussel colonies were found in Kentucky Lake possibly due to human activities increasing the salinity of today’s freshwater resources. The increase in salinity from human activities may have adversely affected the ecosystems and water supplies. The Specific aim of this study was to determine the temporal trend of dissolved calcium in Kentucky Lake …

Exploring The Geometric And Electronic Properties Of Palladium Doped Silicon Clusters, Madison Winkeler, Ciara N. Richardson

Scholars Week

Transition metal-doped silicon clusters have unique properties and have been studied as building blocks for nanomaterials and microelectronics. Here, the structure and properties of candidate palladium doped silicon clusters (SinPd2: n=1-17) were determined using global optimization techniques on a high performance computing cluster at the San Diego Supercomputing Center. Then geometric structures were further optimized utilizing the B3LYP method with 6-311+G(d) basis sets for silicon and lanl2dz pseudopotential for palladium, followed by the larger DSDPBEP86 method with 6-311+G(2d) basis sets for silicon and SDD pseudopotential for palladium, as implemented in the Gaussian 16 program package. The energetics for each cluster …

Investigating Transfer Of Energy Concepts Learned In Physics To Biology Contexts, Brittany Mureno, Eric Mckenzie

Scholars Week

Problem solving interviews were used to investigate student understanding of energy concepts in a biology course for preservice K-8 teachers. Interview subjects constructed an energy-based explanation for a biology scenario. Subjects had previously taken a physics course in which an energy-based model for interactions had been developed. Interviews were transcribed and analyzed to identify common themes in student reasoning. These themes describe discipline-specific understanding, but also cut across disciplines, providing insight into how learners make sense of energy as a unifying concept.

Submonolayer Nucleation In Ultrathin Liquid Films: Scaling Properties And The Effects Of The Critical Nucleus Size, Haley Doran

Scholars Week

Scaling phenomena during submonolayer thin-film formation and growth has been a subject of interest for several decades, motivated in part by its relevance to understanding deposition and growth of technologically-important electrode and semiconductor materials. There are several models that effectively describe various scaling behaviors in regimes where the critical island size i* is very small (typically i* < 4 monomers). These models capture many essential properties of of submonolayer nucleation and growth in vacuum-deposited films quite well, however systems with large i* values such as those that occur during solution-phase nucleation remain unexplored due to the high computational cost of traditional approaches. Such systems are of particular interest for the fundamental understanding of the physics behind the growth of large, low-defect organic crystals via organic-vapor-liquid-solid deposition, which have novel semiconductor applications. Here we discuss a multiscale model that combines traditional mean field and classical nucleation theory approaches with a self-consistent treatment of i*, stochastic treatment of nucleation, and analytically calculated monomer diffusion via the 2D diffusion equation. This approach allows us to model large i* systems and compare scaling patterns to those of small i* systems.

Uniform Dispersion Of Nanoparticles In Pmma Waveguides For Luminescent Solar Concentrators, Daniel Korus

Scholars Week

With the rise of emissions-related climate change, novel renewable energy sources must be realized. At the same time, evolution of the electric distribution grid away from traditionally large, centralized producers toward smaller, decentralized sources drives the need for next generation technologies that can be more readily integrated into the built environment. Nanocrystal (NC)-doped luminescent solar concentrators (LSCs) are waveguides that absorb diffuse and direct broadband sunlight across their surface and direct narrow-bandwidth, high-brightness light to their edges, for conversion into electricity by coupled, bandgap-matched, photovoltaic (PV) cells. LSCs are insensitive to incident light orientation, partial shading, and can be integrated …

Near Real-Time Determination Of The Prevalence Of Cannabinoids, Cathinones, And Synthetic Opioids, Catherine O'Rourke, Bikram Subedi

Scholars Week

Unregulated new psychoactive substances (NPS) in “pure” or “preparation” forms are designed to mimic the effects of controlled substances, and are introduced and reintroduced in the market as a cheap substitute of established regulated drugs in quick succession to loophole the law enforcement efforts on combating drugs. For example, carfentanil, a synthetic opioid activates the opioid receptors similar to morphine but it is astoundingly potent compared to a typical drug of abuse (100 times more potent than fentanyl and 10,000 times more powerful than morphine). Based on the cost- and time-intensive forensic analysis, National Drug Early Warning System reported the …

Polycarbodiimides And Polyguanidines : Their Reactivity And Applications In Covalent Adaptable Networks, Alberto Melchor Bañales

Scholars Week

We have recently discovered a new chemical transformation in which N,N’,N’’ tri-substituted guanidines undergo a thermal exchange reaction. Kinetic investigations indicate that the transformation is first order with respect to the guanidine, indicating a dissociative mechanism in which a carbodiimide and amine are formed as intermediates. This new reaction has been applied to polymer systems. Polycarbodiimides were shown to undergo postpolymerization modification with amines to form polyguanidines at room temperature under an hour. Polyguanidines undergo the newly found chemical transformation to form different substituted polyguanidines. This exchange reaction will be applied to the preparation of a covalent adaptable network by …

Engineering Sortase; Activity And Selectivity Of New Hybrid And Ancestral Variants Of Sortase A, Sarah Struyvenberg

Scholars Week

Bacterial sortase enzymes are a beneficial tool in innovative mechanisms of protein engineering. However, important limitations to utilization of sortases for engineered purposes exist; namely, that sortase A (SrtA) is a relatively poor enzyme and very specific for the substrate containing LPATXG motif. Exciting previous work from our collaborators reveals that sortases from different species recognize different sequences and that activity can vary. Therefore, we wanted to create and investigate hybrid sortase enzymes between SrtA from S. aureus and Streptococcus pneumoniae, wherein we swapped a substrate-interacting loop between the beta-E and beta-F strands. Our hypothesis is that these residues are …

Bottom-Up Shape Engineering Of Organic Molecular Single-Crystals, Griffin Reed

Scholars Week

The ability to fabricate complex submicron-scale components from inorganic crystalline semiconductor materials such as c-Si enables countless modern technologies, from microelectromechanical systems to integrated circuits. For single-crystal molecular materials on the other hand, comparable approaches to defining micron- and submicron-scale structure are much less well developed, in part because weak intermolecular binding forces make molecular crystals vulnerable to damage by conventional techniques such as reactive ion etching, wet etching, and energetic beam milling. Here we show how the same weak forces that are problematic for top-down patterning of molecular crystals can be exploited to enable controlled bottom-up growth, by leveraging …

Hour-Level Resolution On Consumption Pattern Of Substance Abuse, Jarrett Mauk, Rhiannon Huffines, Brittney Nelson, Tara Croft, Bikram Subedi

Scholars Week

Conventional survey-based approaches of determining the consumption statistics of drugs in communities are suffered from non-response biases, and typically underestimate the actual consumption. Time and cost-intensive conventional approaches, therefore, can’t be utilized to determine high-resolution temporal variability in drug consumption. In this study, the temporal trend of consumption of 10 illicit and 26 prescribed neuropsychiatric drugs was determined at hour-level resolution utilizing wastewater-based epidemiology. The hourly composite raw wastewater (every 10 minutes) samples were collected for three consecutive days in a typical week (total of 72 samples), analyzed for target drug residues using UPLC-MS/MS, and back-calculated the consumption rate of …

Uncertainties Treatment For Wastewater-Based Epidemiological Estimation Of The Consumption Of Illicit And Prescribed Neuropsychiatric Drugs In Two Urban Communities In Kentucky Using Ammonium Normalized Population And Monte Carlo Simulation, Rhinannon Huffines, Tara Croft, Manoj Pathak, Bikram Subedi

Scholars Week

The conventional estimation of the prevalence of substance use in a community based on self-reported surveys typically underestimates the actual consumption. Drug’s residues in raw wastewater collected from the centralized wastewater treatment plants were utilized – Wastewater-Based Epidemiology (WBE) – to determine the consumption rate of illicit and prescribed neuropsychiatric residues in two urban communities in eastern Kentucky and two rural communities in western Kentucky. The ammonical nitrogen content in raw wastewater samples was used to minimize the uncertainty associated with the population dynamicity. Uncertainties associated with the several WBE parameters to back-calculate the consumption rate of drugs such as …

Temporal Changes In Dissolved Calcium In Stream And River Waters In Western Kentucky Watershed, Adam Martin

Scholars Week

Temporal Changes in Dissolved Calcium in Stream and River Waters in Western Kentucky Watershed

Structural Studies To Understand The Effects Of N108k T-State Stabilizing Mutation In Circularly Permuted Hemoglobin, Leah Huey

Scholars Week

The primary goal of our project is to develop a functional hemoglobin based oxygen carrier (HBOC) for clinical care. In order to accomplish this, we are working on designing a single chain hemoglobin (scHb) that can serve as the building block of a monodisperse polymeric HBOC. The scHb is formed from novel covalent fusions between the two α chains and two circularly permuted β chains. The initial constructs of non-covalently linked α and cp-β showed decreased stability and low T-state affinity (Asmundson, et. al., 2009). To counter these effects, two point mutations have been included to increase T-state affinity (Tsai …

Broadening The Scope Of Sortase-Mediated Ligations Using Natural Sortase Homologs, Nicholas Horvath

Scholars Week

Sortase-mediated ligations have become an attractive option for protein modification chemistry, enabling the synthesis of a wide range of non-natural polypeptide derivatives. In an effort to expand the scope of this methodology, we have been characterizing the in vitro reactivity of a panel of natural sortase homologs. Here we present our studies on the substrate and nucleophile tolerance of sortases from a range of bacterial species. Notable findings include that sortase A from Streptococcus pneumoniae (SrtApneu) shows a high degree of substrate promiscuity, allowing this enzyme to process a range of substrate variations that deviate from the LPXTG substrate motif …

Effects Of Arabidopsis Thaliana Villin-4 Mutations On Root Hair Physiology, Morphology And Function, Maya Klem, Emily Bossard

Scholars Week

The protein Villin is found in both plants and animals across many taxa. In plants, one of the roles of Villin is to aid in root hair formation and function. They do this by assisting in the formation of actin bundles in root hairs in addition to other processes. It has been found that Arabidopsis thaliana with mutated Villin-4 have compromised actin bundles and in certain cases shorter or dysfunctional root hairs. This study examines the effects that the mutation in Villin-4 proteins has on various parts of plant root physiology. By examining the changes in responses of Arabidopsis thaliana …

Lipid Binding Studies Of Blood Coagulation Factor Viii C1 And C2 Domains, Rachel Blazevic

Scholars Week

Blood coagulation factor VIII is an essential cofactor in the mammalian blood-clotting cascade. FVIII must bind the phospholipid membrane of activated platelets to function as a cofactor for FIXa. The blood coagulation cascade culminates in the formation of a stable blood clot. In humans, the C1 and C2 domains are implicated in binding phospholipid membranes, however the relative contribution of different residues in the lipid-binding mechanism is unclear. Using site-directed mutagenesis, expression of the isolated C1 and C2 domains in Escherichia coli cells, protein purification with metal affinity chromatography, electrospray ionization mass spectrometry, enzyme-linked immunosorbent assays, liposome sedimentation assays, pull …

Intramolecular Reductive Heck Approach To Guaipyridine Alkaloids, Samantha Grosslight, Hope Spargo

Scholars Week

The guaipyridine alkaloids are a family of compounds that all share an unusual carbon structure, whose source plants have been used as a traditional medicine in Southeast Asia. Members of the guaipyridine family include cananodine and the rupestines. Cananodine has been isolated from the fruits of the Canaga odorata in Indonesia, Malaysia and the Philippines. Cananodine has been used of decades as a traditional medicine for the treatment of malaria, infections and fever. Studies of cananodine’s biological activity have reveled activity against Hep G2 and Hep 2,2,15 human hepatocarcinoma cell lines, the most common types of liver cancer. Due to …

Evaluating Nucleophile And Substrate Specificities Of Sortase A Homologs For Orthogonal Reactivity, Nicholas Horvath, Jesse Prelesnik

Scholars Week

Enzymes have become an attractive option for protein modification chemistry due to the remarkable site-specificity they afford. Of particular interest is sortase A from taphylococcus aureus (SrtAaur), which has garnered attention for its ability to install a variety of non-natural modifications to a conserved oligopeptide substrate. In addition to SrtAaur it has become apparent that sortase A homologs exist in other bacterial strains, each of which is potentially a novel catalyst for protein engineering. Previous work has demonstrated that eight representative sortase A homologs exhibit unique specificities for synthetic peptide substrates, capable of identifying characteristic combinations of amino acids in …

Gold Catalyzed Lactonization Of Epoxide Esters, Carlos Enciso Lopez

Scholars Week

Lactones are cyclic esters of varying ring size that occur naturally in organic compounds. Organic structures such as these have various useful biological activities applicable to antibacterial drugs, potential anticancer drugs, and participants of metabolic processes. Gold catalysts Au(I) and Au(III) are shown in our experiments to be effective in inducing intramolecular lactonization of epoxide esters to form desired lactone products. In our experiments gold catalysts coordinated with epoxides to develop a positive charge on the carbon nearest to the carbonyl. The result is an intramolecular lactonization of the ester via nucleophilic attack of the carbonyl oxygen onto the positive …

Solving The Molecular Structure Of Hybrid Human-Porcine Factor Viii Through X-Ray Crystallization, Mikko Sayre, Amanda Weis, Brenna Park-Egan

Scholars Week

Factor VIII (fVIII) is a protein that is involved in the coagulation cascade, a collection of reactions that is activated by injury and leads to the formation of blood clots. Deficiencies in fVIII lead to the bleeding disorder hemophilia A, a condition that occurs in 1 in 5000 births. The current treatment for hemophilia A is inefficient and costly; however, there is potential through the use of recombinant hybrid human-porcine fVIII. Hybrid fVIII shows up to 12-fold higher coagulant activity than human fVIII, and can retain its activity even in the presence of inhibitory antibodies. The primary objective of our …

Surface-Enhanced Raman Scattering Optical Fibers As Chemical Sensors, Deanna Myers, Luke Degraaff

Scholars Week

There is a great need to be able to measure chemical environments at both the cellular and sub- cellular levels in real time because chemical irregularities in these environments are indicative of many disease states. In this project, a surface-enhanced Raman scattering (SERS) based optical fiber sensor is designed to monitor pH in real time. SERS spectra of reporter molecules adsorbed on the fiber are used to deliver information on the chemical composition of the environment.

Structural Studies Of A Circularly Permuted Human Hemoglobin Containing Low O₂-Affinity Mutations, Rachel Hubbard

Scholars Week

Our research is focused on the production of a hemoglobin-based oxygen carrier (HBOC) which can be used as a therapeutic in the event of acute blood loss. The administration of cell-free hemoglobin is associated with severe adverse effects due to dissociation of the tetrameric α₂β₂ complex into αβ heterodimers. Our approach to designing an effective HBOC is based on a recombinant circularly permuted human hemoglobin in which all of the subunits are linked in a single-chain fashion. This design would prevent the dissociation of the tetramer and allow for the biosynthesis of polymeric hemoglobins of defined mass. Preliminary ligand binding …