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Full-Text Articles in Physical Sciences and Mathematics

The Regulation Of Atg9a-Mediated Aggrephagy By An Ulk1-Independent Atg13-Atg101 Complex, Joshua Youngs Jun 2022

The Regulation Of Atg9a-Mediated Aggrephagy By An Ulk1-Independent Atg13-Atg101 Complex, Joshua Youngs

Undergraduate Honors Theses

Aggrephagy, a type of autophagy, is an essential cellular process by which protein aggregates are collected and broken down in the lysosome. Protein aggregates are implicated in several diseases including Alzheimer’s disease, diabetes, and cancer. Here, we investigate the ATG13-ATG101 protein complex, a sub-complex of the canonical ULK1 complex whose regulatory role in aggrephagy is not completely understood. We also develop a protein fragment complementation (PFC) assay using the biotin ligase TurboID to study the functions of the ATG13-ATG101 complex with increased specificity. We demonstrate that ATG13 is required for optimal degradation of p62-ubiquitin condensates. We also show that a …


Characterization Of Bimetallic Silver-Copper Nanoinks With Hydroxyethyl-Cellulose Additives, Daniel Brunick May 2022

Characterization Of Bimetallic Silver-Copper Nanoinks With Hydroxyethyl-Cellulose Additives, Daniel Brunick

Undergraduate Honors Theses

Coinage metal nanoparticles remain an intriguing subject for research due to their industrial versatility. Primary applications of coinage metal nanoparticles include printed electronics, solar panels, and sensors. Inks formulated with the nanoparticles are conductive and thus useful for fabricating sensors. Silver-copper nanoalloy inks are viable for the fabrication of flexible sensing devices for the detection of volatile organic compounds. One of the challenges is the ability to synthesize composition-controllable alloy nanoparticles at room temperature through wet chemical methods and achieve controllable sintering at room temperature. This work addresses the challenges by investigating the room-temperature synthesis of silver-copper alloy nanoparticles and …


Synthesis And Characterization Of Hydrazine Derivatives Of Coumarin For Bioorthogonal Chemistry Inside Cells, Akiva J. Grimaldi May 2022

Synthesis And Characterization Of Hydrazine Derivatives Of Coumarin For Bioorthogonal Chemistry Inside Cells, Akiva J. Grimaldi

Undergraduate Honors Theses

Protein carbonylation is one manifestation of oxidative stress, which is characteristic of many diseases. Our lab has developed several coumarin-hydrazine based fluorescent probes capable of detecting carbonylation in live cells via the formation of hydrazone conjugates. As an effort to expand and improve on these achievements, this work presents new data regarding the synthesis and characterization of three such probes. Two of the probes—julolidine coumarin hydrazide (JCH) and trifluoromethyl coumarin hydrazine (TFCH)—were previously synthesized by our lab. Here, JCH is studied in terms of its reaction speed and fluorescence enhancement in acylhydrazone formation with aldehydes under various conditions and catalytic …


Optimization Of Paper-Based Substrates For Surface Enhanced Raman Spectroscopic Biosensor Development, Kaylee M. Cappuccio May 2022

Optimization Of Paper-Based Substrates For Surface Enhanced Raman Spectroscopic Biosensor Development, Kaylee M. Cappuccio

Undergraduate Honors Theses

Advancements in the field of analytical chemistry have greatly expanded the development of biosensors for the detection of a wide array of diseases. This study aims to optimize an affordable paper-based nanocomposite biosensor that utilizes surface-enhanced Raman spectroscopy (SERS). Specifically, it investigates the preparation parameters for a paper-based SERS substrate, including nanoparticle administration and drying procedures. A particular focus of this work is to assess how the wax-defined paper channels can effectively enhance SERS intensity. The results revealed that while the wax-printed wells can define the nanoparticle administration for SERS detection, wax backing may reduce the sensitivity of SERS by …


Computational Analysis Of A Mn-Based Electrocatalyst With Primary Amine Substituents In The Secondary Coordination Sphere For Co2 Reduction, Erin Urban May 2022

Computational Analysis Of A Mn-Based Electrocatalyst With Primary Amine Substituents In The Secondary Coordination Sphere For Co2 Reduction, Erin Urban

Undergraduate Honors Theses

The purpose of this research was to report the mechanism for the two-electron, two-proton conversion of CO 2 to CO and H 2 O using a manganese(I) electrocatalyst, Mn(L)(CO) 3 Br (where L = bipyridyl ligand with aryl-amine moieties installed at the 6 position of 2,2’-bipyridine), synthesized by the Jurss group, including any other competing reactions, such as the hydrogen evolution reaction (HER). The “protonation- first” and “reduction-first” pathways were considered for CO 2 RR. Density functional theory (DFT) calculations were performed to determine the redox potentials and Gibb’s free energies for each step in the mechanism for CO 2 …


Synthesis And Characterization Of Ternary Pt Nanoally Catalysts For Fuel Cells, Ylith Peck May 2022

Synthesis And Characterization Of Ternary Pt Nanoally Catalysts For Fuel Cells, Ylith Peck

Undergraduate Honors Theses

A hydrogen fuel cell is an electrochemical device that converts oxygen and hydrogen into electrical energy while producing water as the only by-product, which has attracted growing interest, especially in the automotive industry. This technology is efficient and has zero pollution to the environment, in contrast to the direct use of fossil fuels in combustion engines which produce pollution and greenhouse gas emissions. One of the key components for hydrogen fuel cells is the catalyst that operates at the cathode, which currently use platinum. Due to the scarce amount of platinum in the world, the manufacturing cost for fuel cells …


Friedel-Crafts Alkylation Of Benzene With A Superacid Catalyst, Josh T. Cutright May 2022

Friedel-Crafts Alkylation Of Benzene With A Superacid Catalyst, Josh T. Cutright

Undergraduate Honors Theses

Long-chain alkylbenzenes are industrially synthesized precursors to commercial surfactants such as laundry detergent. The currently used catalysts in the processes of their synthesis are corrosive and harmful to the environment. These problems can be avoided utilizing heterogeneous highly acidic catalysts. Solid catalysts do not corrode equipment and are relatively simple to remove from the post-reaction mixture. Phosphotungstic acid (PTA) supported on silica gel could be a possible catalyst due to its high acidity with an estimated pKa ≈ -13. The catalyst PTA-SiO2 was prepared via the sol-gel method to covalently embed it in a silica support. The catalyst was …


Nitrogen Doping Of Electrochemically Activate Carbon Screen-Printed Electrodes, Ethan Galloway May 2022

Nitrogen Doping Of Electrochemically Activate Carbon Screen-Printed Electrodes, Ethan Galloway

Undergraduate Honors Theses

Screen printed electrodes (SPEs), which are prepared by patterning conductive inks or pastes onto an insulating support (e.g., plastic film), are widely employed as sensing and biosensing platforms due to their ease of fabrication and relatively low cost. This is especially applicable to electrodes of this nature prepared with carbon-based inks (SPCEs). To date, the most successful and significant commercial application of SPEs has been as test strips for glucose meters. Despite the maturity of this technology, SPE research remains very active as improvements in sensitivity and selectivity, which often involve modifying the electrode surface, hold the key to advancing …


Extraction And Partial Purification Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Strain Kchxc3, Elizabeth Bond May 2022

Extraction And Partial Purification Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Strain Kchxc3, Elizabeth Bond

Undergraduate Honors Theses

Rhodococcus bacteria have many secondary metabolic pathways that may produce novel natural products. The bacterium Rhodococcus strain KCHXC3 was isolated from a soil sample collected near Kingsport, Tennessee and was found to produce an inhibitory compound active against a broad array of bacterial species, including the Gram negative pathogen Shigella sonnei. The aim of this research is to extract and purify the compound for future structure elucidation. A mixture of compounds from 3 month old agar plates inoculated with strain KCHXC3 was extracted using ethyl acetate. The crude extract was then partially purified utilizing a Sephadex LH-20 column, followed …


Differential Protein Expression In Bacteriophages Crimd And Larva, Daria Moody May 2022

Differential Protein Expression In Bacteriophages Crimd And Larva, Daria Moody

Undergraduate Honors Theses

Proteomics studies allow us to answer questions about differential protein expression across different systems. Mass spectrometry is a powerful tool in these studies due to the distinct masses of the amino acids that compose proteins. In our experiment, we used a bottom-up approach and focused on two bacteriophages found on the William & Mary campus, CrimD and Larva. The infection of Mycobacterium smegmatis, a nonpathogenic model for tuberculosis, by these two bacteriophages was frozen at five different timepoints, and our goal was to compare the differential protein expression across the samples in order to gain a greater understanding of …


Gas-Phase Proton Affinities For Twenty Of The Proline-Containing Dipeptides, Henry Cardwell May 2022

Gas-Phase Proton Affinities For Twenty Of The Proline-Containing Dipeptides, Henry Cardwell

Undergraduate Honors Theses

Peptide fragmentation plays a crucial role in the analysis of proteins through mass spectrometry-based proteomics. Most proteomics experiments take place in the low-energy regime and are governed by the mobile proton model which predicts random cleavages along the peptide backbone; however, there sometimes arise circumstances where the mobile proton model fails causing sequencing algorithms to misidentify peptides. One such example is noted in the “proline effect” wherein proline-containing peptides preferentially fragment N-terminal. While it has been established that the “proline effect” is due to the rigidity and basicity of the proline N-terminus, a further understanding of the factors influencing the …


Chemical Analysis Of Organic Compounds In Dew Water, Monica Dibley May 2022

Chemical Analysis Of Organic Compounds In Dew Water, Monica Dibley

Undergraduate Honors Theses

Water films on outdoor surfaces, such as dew, can act as a reservoir for organic molecules deposited from the atmosphere and they present a potential reactive medium for chemical transformations. To better understand the flux of volatile organic compounds from evaporating films, the composition and reactivity of the complex mixture of dissolved organic material (DOM) found in these films need to be characterized. Previous studies have measured the salts and the small organic molecules in dew collected on clean Teflon surfaces or condensers. Here, we expand on this by probing the organic chemicals found on natural outdoor surfaces covered in …


Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran Apr 2022

Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran

Undergraduate Honors Theses

Anthropogenic activities generate metal, acid, and particulate air pollutants which negatively impact human and ecological health. In the United States, power plant, industrial, and vehicle emissions are leading causes of air pollution, however, the measurement of air pollution at high-resolution spatial regimes remains a challenge. Honey has emerged as a powerful biomonitoring tool to effectively quantify contaminants without the need for a large array of monitoring instruments. I hypothesized that honey could be used to effectively measure and map modern air pollutant spatiotemporal relationships over the Eastern U.S. Using ion chromatography with sulfate as an indicator for air pollution and …


Geologic Controls On 137cs Cycling By Terrestrial Vegetation In The Eastern U.S., Kathleen Chellman Apr 2022

Geologic Controls On 137cs Cycling By Terrestrial Vegetation In The Eastern U.S., Kathleen Chellman

Undergraduate Honors Theses

137Cs is a radioactive trace metal (T1/2 = 30 y) that was dispersed globally by nuclear weapons testing in the 1950s-1960s. Prevailing winds and precipitation systems caused some areas far from the test sites to receive significant fallout, which is still easily measured in soils, sediments and even some vegetation in the Eastern United States. Recent work near Chernobyl and Fukushima indicates that trace levels of 137Cs can harm insects, pollination services, and other ecological functions. In areas with low soil potassium, 137Cs is cycled in vegetation; however, soil potassium alone doesn't consistently predict the 137 …


Dirhenium Compounds Containing The Diphosphine Ligands Ph2pch2pph2, Ph2pch(Cn)Pph2, Or Ph2pch(Ch3)Pph2: A Comparative Study, Hannah C. Arthur Jan 2022

Dirhenium Compounds Containing The Diphosphine Ligands Ph2pch2pph2, Ph2pch(Cn)Pph2, Or Ph2pch(Ch3)Pph2: A Comparative Study, Hannah C. Arthur

Undergraduate Honors Theses

When M2L10 complexes containing two rhenium(III) atoms in a quadruple bond react with an excess of the diphosphine ligand Ph2PCH2PPh2, the bond order decreases, and the rhenium is reduced to rhenium(II). When two diphosphine ligands are bonded to the dirhenium center, they can adopt a trans-trans, trans-cis, or cis-cis configuration. NMR spectra of compounds that adopt the cis-cis arrangement show unusually large downfield shifts for one of the bridgehead methylene hydrogens (P-CH2-P). To understand the unusual chemical shift, the hydrogens first have to be assigned. The strategy for …