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Full-Text Articles in Physical Sciences and Mathematics

Advancements In Forensic Analysis: Development Of Mass Spectrometric And Chemometric Approaches For The Identification Of Synthetic New Psychoactive Substances And Plant Materials, Mónica Ventura Jan 2024

Advancements In Forensic Analysis: Development Of Mass Spectrometric And Chemometric Approaches For The Identification Of Synthetic New Psychoactive Substances And Plant Materials, Mónica Ventura

Electronic Theses & Dissertations (2024 - present)

While forensic science is a well-established discipline, a number of federal agencies have highlighted challenges that continue to plague the field and the extent to which these challenges remain unaddressed. Examples are the illegal trade of wildlife timber and the drug epidemic. Characterization of these materials requires nuanced method development for compound determination, matrix material-specific protocols, and heavy use of expensive consumables. The application of a technique such as direct analysis in real time – high-resolution mass spectrometry (DART-HRMS) provides the opportunity to circumvent many of the challenges presented by conventional methods. In general, little to no sample preparation is …

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Self-Quenching Of Carbon Monoxide In The Presence Of Noble Gases, Madeline V. Hinkle Jan 2024

Self-Quenching Of Carbon Monoxide In The Presence Of Noble Gases, Madeline V. Hinkle

Honors Theses

Precise rate coefficients for the vibrational relaxation pathways of CO(v)-CO in the presence of Ar and Kr have been determined through the work of this thesis. This work was motivated by the need to find a more cost-effective alternative to using xenon as a bath gas, which has increased significantly in price in the past few years. Similar experiments within this lab at Bucknell have been conducted in the past using argon, which can be used in the same manner as xenon but comes at a much lower price, but the experiments yielded inferior results compared to those using xenon. …

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Exploration Of Sulfonamides And Benzothiazoles As Peptide-Based Cleavable Linkers, Abigail Dalton Jan 2024

Exploration Of Sulfonamides And Benzothiazoles As Peptide-Based Cleavable Linkers, Abigail Dalton

Honors Theses

Cleavable linkers have demonstrated great potential in various applications of medicinal organic chemistry, such as in modern therapeutic development. Linkers are stable compounds that cleave in specific conditions to release molecular cargo. We have developed cleavable linkers based on nucleophilic aromatic substitution reactions on sulfonamide and benzothiazole substrates in small molecule and in peptide studies. Sulfonamides, commonly with an electron-withdrawing group, reacted in high conversion of starting material to the sulfide product in small molecule studies, but was unable to successfully cleave the sulfonamide linker on peptide in mild conditions. Next, a benzothiazole sulfone substrate was analyzed and optimized in …

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The Effect Of Solvent Identity And Hydride-Donor On The Reduction Of Co2 Into Useful Fuels, Abigail Mcentire Jan 2024

The Effect Of Solvent Identity And Hydride-Donor On The Reduction Of Co2 Into Useful Fuels, Abigail Mcentire

Honors Theses

One possible strategy for decreasing CO2 emissions is through electrocatalytic reduction reactions to convert the CO2 back into combustible fuels , such as methane or methanol. However, it can be challenging to control the reaction to select one of these useful fuels as opposed to carbon monoxide or formate. Our strategy is to investigate a specific hydride donor and solvent combinations for which the reaction favors conversion to methanol. It was found that in acetonitrile , several hydride donors were capable of selective reduction of CO2 to the methanol oxidation state.

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Advanced Mass Spectrometry Method Development And Applications For Assessment Of Traumatic Brain Injury And Legionella Pneumophila Dissinfection With Copper, Austin Chase Sigler Jan 2024

Advanced Mass Spectrometry Method Development And Applications For Assessment Of Traumatic Brain Injury And Legionella Pneumophila Dissinfection With Copper, Austin Chase Sigler

Doctoral Dissertations

"Pathological processes often involve complex biochemical changes which can be assessed using advanced mass spectrometry. In this present dissertation, two fields were studied: traumatic brain injury (TBI), and water contamination by L. pneumophilia. TBI is a pressing public health concern for which current clinical tools remain inadequate. We present newly developed mass spectrometric methods to access metabolites associated with blast induced TBI. We applied these methods to the biofluids of soldiers conducting explosives training. Significant changes in several metabolites were observed between pre- and post-blast specimens, including changes that increased with repeated exposure. These changes point to the possibility of …

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Analytical Methods For Monitoring Traumatic Brain Injury Biomarkers/Treatment And Pharmaceutical Residual Solvents, Olajide Philip Adetunji Jan 2024

Analytical Methods For Monitoring Traumatic Brain Injury Biomarkers/Treatment And Pharmaceutical Residual Solvents, Olajide Philip Adetunji

Doctoral Dissertations

"The development of highly sensitive and efficient analytical methods utilizing advanced instrumentation is necessary to help improve disease diagnosis and therapeutics. A major neuro-consequence of traumatic brain injury (TBI) is oxidative stress from the generation of reactive oxygen species and the depletion of antioxidant defenses. Alteration in concentrations of certain small molecules also occurs with the disease progression and can help understand TBI pathophysiology. Two analytical methods employing liquid chromatography with tandem mass spectrometry (LC-MS/MS) were developed and validated to monitor the potential small-molecule TBI biomarkers at sub-ppb levels. Subsequently, the neuroprotective effect of an antioxidant prodrug, N-acetylcysteine amide (NACA), …

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Catalytic Control Of The Nanomorphology And Mechanical Properties Of Aliphatic Shape-Memory Aerogels, A B M Shaheen Ud Doulah Jan 2024

Catalytic Control Of The Nanomorphology And Mechanical Properties Of Aliphatic Shape-Memory Aerogels, A B M Shaheen Ud Doulah

Doctoral Dissertations

"Shape-memory poly(isocyanurate-urethane) (PIR-PUR) aerogels are nanoporous solids that can return to their original shape after being compressed, through a heating actuation step. This thesis compares the effectiveness of various metal ions as catalysts in the formation of PIR-PUR aerogels, and explores the correlation between catalytic activity, nanomorphology, and mechanical properties of the resulting aerogels. The gelation rate was found to increase from Fe to Cu and then decline from Cu to Ga in the periodic table. CuCl2 was found to be the fastest catalyst, and FeCl3 the slowest. The morphology of the aerogels changed from bicontinuous to spheroidal …

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Assessing Interatomic Potentials For Molecular Dynamics Simulation Of Soybean Oil Pyrolysis, Tanner Garrett Rust Jan 2024

Assessing Interatomic Potentials For Molecular Dynamics Simulation Of Soybean Oil Pyrolysis, Tanner Garrett Rust

MSU Graduate Theses

The world today relies on hydrocarbon combustion for many reasons, including its high energy density that provides ease of transportation. However, hydrocarbons sourced from fossil fuels are not expected to last forever. Biodiesel, a renewable alternative, has many attractive benefits but comes with other downsides. Biodiesel can gel in cold environments and may leave residue in an engine. Pyrolysis of biodiesel has shown promise in addressing these common detriments. Inducing pyrolysis on biodiesel feedstock (commonly soybean oil in the USA) would be an attractive option presuming it continues to produce fossil fuel analogs similar to biodiesel pyrolysis. Herein, Langevin molecular …

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Development Of Functional Plasmonic Nanoceria For The Ultrasensitive Detection Of Ebola Glycoprotein, Carissa A. Sutton Jan 2024

Development Of Functional Plasmonic Nanoceria For The Ultrasensitive Detection Of Ebola Glycoprotein, Carissa A. Sutton

MSU Graduate Theses

Infectious diseases have been increasing in both severity and prevalence, leading to increasing economic burdens and health concerns. Ebola hemorrhagic fever is an infectious disease that is both highly communicable and highly fatal. Current detection methods for the virus have high specificity and sensitivity but have long and/or complicated procedures that do not allow for early virus detection in highly affected areas. Compared to the lengthy procedure of reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR is more time-efficient; however, specificity and sensitivity are reduced. Since early detection of the virus is the only way to increase survival rates, sensitive detection …

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Inorganic Chemical Reasoning Skills: An Exploratory Study Into Understanding Students’ Choices And Thought Processes, Hannah P. Thompson Jan 2024

Inorganic Chemical Reasoning Skills: An Exploratory Study Into Understanding Students’ Choices And Thought Processes, Hannah P. Thompson

MSU Graduate Theses

Predicting the products of reactions is a fundamental skill for practicing inorganic chemists. However, the current knowledge of the strategies that students use to solve them is limited. Presumably, instructors of inorganic chemistry courses give complete-the-reaction assessment items hoping that students will use their knowledge of inorganic concepts to solve them; but it is conceivable that a successful student could use heuristics or domain general problem-solving methods. I proposed this study to determine which strategies were used by students when solving complete-the-reaction tasks in inorganic chemistry, and also to make qualitative connections between strategy and accuracy. This was done in …

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Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam Jan 2024

Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam

Publications and Research

In breast x-ray imaging scattered radiation adds 50% of harmful radiation dose from anisotropic Compton scattering mechanism. We have been working with double layered inorganic salt materials that can induce Compton scattering to the incident mammographic x ray beams (in 20-30 kVp range) with adequate isotropy (angular control). Typically metal nitrates and alkali halide salt layers are shown here to cause low energy radiation interference zones with high and low photon intensities and local flux heterogeneity in terms of flux covariance. Spatial variation of low energy photon flux creates concentrated and sparse radiation zones that may be used to induce …

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Enhancing Uptake Capability Of Green Carbon Black Recycled From Scrap Tires For Water Purification, Jiho Choi, Jihyun Kang, Huiseong Yang, Sangin Yoon, Jun-Hyun Kim, Hyun-Ho Park Jan 2024

Enhancing Uptake Capability Of Green Carbon Black Recycled From Scrap Tires For Water Purification, Jiho Choi, Jihyun Kang, Huiseong Yang, Sangin Yoon, Jun-Hyun Kim, Hyun-Ho Park

Faculty Publications – Chemistry

This study reports on the highly simple fabrication of green carbon black (GCB) generated from scrap tires with acetic acid to improve the adsorption efficiency for water purification, which is thoroughly compared with conventional carbon black (CB) obtained from petrochemicals. Unlike traditional modification processes with strong acids or bases, the introduction of a relatively mild acid readily allowed for the effective modification of GCB to increase the uptake capability of metal ions and toxic organic dyes to serve as effective adsorbents. The morphological features and thermal decomposition patterns were examined by electron microscopy and thermogravimetric analysis (TGA). The surface functional …

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Activation Of Hydrogen By Sterically Modulated Coinage Metal Catalysts Via Mutual Quenching Of Hard/Soft Acid/Base Mismatches, Zach Leibowitz Jan 2024

Activation Of Hydrogen By Sterically Modulated Coinage Metal Catalysts Via Mutual Quenching Of Hard/Soft Acid/Base Mismatches, Zach Leibowitz

Honors Projects

To mitigate the devastating environmental impacts of climate change in the coming decades, it is imperative that we replace the use of fossil fuels with renewable energy sources such as wind, solar, and hydroelectric. As these renewable energy sources are inherently intermittent, there exists a need for sustainable mechanisms to store renewable energy for later use. While the direct use of dihydrogen (H2) as a combustible fuel would allow for energy storage without the harmful release of carbon dioxide (CO2) upon combustion, the practicality of H2 as a synthetic fuel is limited by its low …

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Extraction Of Capsaicin Using The Polyol Induced Extraction (Pie) Method, Orlando Herrera Jan 2024

Extraction Of Capsaicin Using The Polyol Induced Extraction (Pie) Method, Orlando Herrera

All Student Theses and Dissertations

Polyol-induced extraction (PIE) is an extraction technique for separating organic solvents from water, using glycerol and polyol as separating agents. Glycerol binds water releasing the organic solvent as a separate liquid phase. this thesis, investigates how the PIE process may be used to separate caffeine and capsaicin. When acetonitrile and water are used as a 1:1 solvent mixture, two immiscible phases are created upon addition of the polyol, glycerol. Initially, for purposes of training on the PIE method, the studies primarly began with the extraction of pure caffeine. Using a 1:1 mixture of acetonitrile and water, 20 m/v % glycerol, …

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Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan Jan 2024

Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan

OES Faculty Publications

In this Research Topic, we bring together ten articles from the diverse research communities interested in the marine iodine cycle, including paleoceanographers, atmospheric chemists, and biogeochemists. The physical chemistry underpinning iodine’s chemical speciation and transformations in the ocean is reviewed by Luther; this paper provides a theoretical basis for the field observations presented in this Research Topic.

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Intercalibration: A Cornerstone Of The Success Of The Geotraces Program, Ana Aguilar-Islas, Hélène Planquette, Maeve C. Lohan, Walter Geibert, Gregory Cutter Jan 2024

Intercalibration: A Cornerstone Of The Success Of The Geotraces Program, Ana Aguilar-Islas, Hélène Planquette, Maeve C. Lohan, Walter Geibert, Gregory Cutter

OES Faculty Publications

The international GEOTRACES program was developed to enhance knowledge about the distribution of trace elements and their isotopes (TEIs) in the ocean and to reduce the uncertainty about their sources, sinks, and internal cycling. Recognizing the importance of intercalibration from the outset, GEOTRACES implemented intercalibration efforts early in the program, and consensus materials were generated that included the full range of TEIs dissolved in seawater, in suspended particles, and from aerosols. The GEOTRACES section cruises include “crossover station(s)” that are occupied by two or more sections and whereby all aspects of sample collection, preservation, and processing can be compared and …

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Assessing The Spatiotemporal Variability Of Dissolved Organic Matter Fluorescence Composition In The Lake George, Ny Watershed, Aleksandar I. Goranov, Mark W. Swinton, David A. Winkler, Jeremy L. Farrell, Sandra A. Nierzwicki-Bauer, Sasha Wagner Jan 2024

Assessing The Spatiotemporal Variability Of Dissolved Organic Matter Fluorescence Composition In The Lake George, Ny Watershed, Aleksandar I. Goranov, Mark W. Swinton, David A. Winkler, Jeremy L. Farrell, Sandra A. Nierzwicki-Bauer, Sasha Wagner

Chemistry & Biochemistry Faculty Publications

Lake George (LG) is a temperate, oligotrophic, medium-sized lake (114 km2) located in northeastern New York State (U.S.). Lakes are highly understudied environments where extensive dissolved organic matter (DOM) processing occurs. With this study we establish the foundation for researching the organic biogeochemistry of the LG watershed, in particular, the numerous tributaries flowing into the lake. Collected were 213 samples from 64 tributaries and 12 lake locations. Some of the tributaries had unique wastewater, agricultural, or wetland influences. We employed fluorescence spectroscopy, a common biogeochemical technique, to characterize the fluorescent DOM (FDOM) component. We developed a parallel factor …

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Green Oxidation Of Aromatic Hydrazide Derivatives Using An Oxoammonium Salt, Nidheesh Phadnis, Jessica A. Molen, Shannon M. Stephens, Shayne M. Weierbach, Kyle M. Lambert, John A. Milligan Jan 2024

Green Oxidation Of Aromatic Hydrazide Derivatives Using An Oxoammonium Salt, Nidheesh Phadnis, Jessica A. Molen, Shannon M. Stephens, Shayne M. Weierbach, Kyle M. Lambert, John A. Milligan

Chemistry & Biochemistry Faculty Publications

Aromatic diazenes are often prepared by oxidation of the corresponding hydrazides using stoichiometric quantities of nonrecyclable oxidants. We developed a convenient alternative protocol for the oxidation of aromatic hydrazides using Bobbitt's salt (1), a metal-free, recyclable, and commercially available oxoammonium reagent. A variety of aryl hydrazides were oxidized within 75 min at room temperature using the developed protocol. Computational insight suggests that this oxidation occurs by a polar hydride transfer mechanism.

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Problems In Chemical Graph Theory Related To The Merrifield-Simmons And Hosoya Topological Indices, William B. O'Reilly Jan 2024

Problems In Chemical Graph Theory Related To The Merrifield-Simmons And Hosoya Topological Indices, William B. O'Reilly

Electronic Theses and Dissertations

In some sense, chemical graph theory applies graph theory to various physical sciences. This interdisciplinary field has significant applications to structure property relationships, as well as mathematical modeling. In particular, we focus on two important indices widely used in chemical graph theory, the Merrifield-Simmons index and Hosoya index. The Merrifield-Simmons index and the Hosoya index are two well-known topological indices used in mathematical chemistry for characterizing specific properties of chemical compounds. Substantial research has been done on the two indices in terms of enumerative problems and extremal questions. In this thesis, we survey known extremal results and consider the generalized …

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Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi Jan 2024

Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi

Chemistry & Biochemistry Theses

Reduction of esters to aldehydes poses a challenge since the resulting aldehydes are often more reactive than the initial esters toward nucleophilic hydride-reducing agents. Although bulky, more controllable reducing agents such as lithium tri-tert-butoxyaluminum hydride or diisobutylaluminum hydride (DIBAL-H) have been developed, they are hazardous, sensitive to moisture and air, needing strict reaction conditions, and unsuitable with a wide range of functional groups. We present the design of an iridium-catalyzed chemoselective hydrosilylation method for dicarboxylic imides, followed by hydrolysis to eliminate the amide and yield aldehydes. This approach offers versatility in general reduction chemistry, holds promise for application …

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Chirality Determination Using Three-Wave Mixing Microwave Spectroscopy, Nicole Taylor Moon Jan 2024

Chirality Determination Using Three-Wave Mixing Microwave Spectroscopy, Nicole Taylor Moon

Doctoral Dissertations

"Rotational spectroscopy has established itself as a reliable gas-phase spectroscopic technique for the structural determination of molecules. This reliability has stemmed from both advancements in microwave technology and a willingness from the community to push the boundaries of the field. In this dissertation, the boundaries are tested in both how well the technique can determine the structure of molecules exhibiting large amplitude motion and through chirality determination. The first half of this dissertation explores the use of deep averaging to determine the structure of silicon containing molecules in collaboration with Dr. Guirgis from the College of Charleston. For each of …

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Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss Jan 2024

Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss

Chemistry & Biochemistry Dissertations

Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is a method used to increase solid-phase microextraction sampling of semi-volatile organic compounds. Three studies were conducted using Vac-HS-SPME via gas chromatography - mass spectrometry (GC-MS) methods for analysis of various sample types. First, a study was performed using Vac- HS-SPME combined with a high-capacity (HC) SPME Arrow to determine the operational fundamentals and workflow necessary to achieve optimal extraction of semi-volatile compounds from a model solid matrix (Ottawa sand). The fundamentals investigated included the seals necessary to create a leak-free sampling vial under vacuum conditions; the magnitude of the vacuum exerted, and the time …

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Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski Jan 2024

Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski

Chemistry & Biochemistry Theses

Dolerophanite Cu2OSO4 is a rare mineral found almost exclusively in the fumaroles of volcano systems and is sensitive to temperature and humidity conditions. It has a monoclinic C2/m crystal structure characterized by two-dimensional layers composed of sulfate anions dispersed amongst copper (II) oxide backbones. There has been recent interest in dolerophanite due to the magnetic properties of its Kagome-like lattice as well as its potential use as a photocatalyst or Li-ion battery electrode. Literature on the material however has been limited by the available synthesis strategies. As such, this thesis work presents a novel strategy …

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Synthesis Of Hydroxycinnamate Derivatives And Characterization Of Bioactivity As Radical Scavengers And Α-Glucosidase Inhibitors, Cate Simmermaker Jan 2024

Synthesis Of Hydroxycinnamate Derivatives And Characterization Of Bioactivity As Radical Scavengers And Α-Glucosidase Inhibitors, Cate Simmermaker

University of the Pacific Theses and Dissertations

Hydroxycinnamic acids (HCAs), a class of polyphenols commonly found in regularly consumed fruits and vegetables, have been investigated for efficacy as radical scavengers and glycosidase inhibitors. These compounds could mitigate the negative health effects of free radicals in oxidative stress diseases including neurodegeneration, cancer and diabetes. The HCAs investigated were caffeic acid (1), p-coumaric acid (2), ferulic acid (3), and sinapic acid (4). The compounds were derivatized with synthetically prepared amino acid esters through a four-step synthesis including protective acetylation, chlorination of the carboxylic acid, amidation, and subsequent deprotection of all applied protecting groups. The inclusion of diverse derivative groups …

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Hybridization Kinetics Of Four-Way Junctions Localized On A Dna Scaffold, Katherine N. Taylor Jan 2024

Hybridization Kinetics Of Four-Way Junctions Localized On A Dna Scaffold, Katherine N. Taylor

Honors Undergraduate Theses

DNA computing is an ever-growing field with scientists trying to design structures that optimize logic gate communication to develop fast, biologically compatible, computational structures. We hypothesize that by using the principles of DNA computing, it is possible to design a DNA tile capable of studying localized DNA hybridization that can differentiate between oligonucleotides of different structural conformations. This includes synthetically manipulating DNA into a nanostructure that can perform Boolean logic functions to calculate the different rates of hybridization. To test our hypothesis, we designed a DNA Tile that incorporated a 4WJ using YES logic. Linear and hairpin single-stranded (ss) DNA …

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Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl And Imine Electrophiles, Stephen Collins Jan 2024

Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl And Imine Electrophiles, Stephen Collins

Theses and Dissertations

The carbon scaffold of many drugs and natural products contain multiple stereogenic centers bearing heteroatoms. As a result of this, chemists have long sought methods to efficiently install these multi-heteroatom functionalities. Reductive coupling reactions have been extensively studied over the past decades, and the allylation of carbonyls via the reductive coupling approach has been a key method for generating chiral allylic alcohols. This work utilizes inexpensive Cu for the asymmetric reductive coupling of allenamides with carbonyls or imines to simultaneously install two heteroatoms (either oxygen and nitrogen or nitrogen and nitrogen, respectively) onto the product. These molecules have a polarity …

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Measuring The Properties Of Rod-Shaped Bacteria By Single-Entity Electrochemistry, Ashley Tubbs Jan 2024

Measuring The Properties Of Rod-Shaped Bacteria By Single-Entity Electrochemistry, Ashley Tubbs

Theses and Dissertations

Antibiotic-resistant bacteria pose a significant and escalating threat to hospitals around the world, necessitating the development of rapid and sensitive detection methods. Single-entity electrochemistry has emerged as a promising approach for detecting and identifying such bacteria, and monitoring the efficacy of antibiotics in real-time. Herein, we employ the translational diffusion equation for circular cylinders to predict the collision frequency of rod-shaped bacteria, informing our experimental setup. Our work demonstrates that lab-fabricated Pt ultramicroelectrodes can sensitively detect bacteria at femtomolar concentrations under migration-controlled conditions. Further, we present a method implemented in MatLab to automate the analysis of step-like signals observed in …

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Photoinduced Alpha-Hydroxy C–H Alkylation Of Mono-Alcohols Via Hydrogen Atom Transfer (Hat) Of An Activated Boron-Containing Complex, Courtney Deanna Glenn Jan 2024

Photoinduced Alpha-Hydroxy C–H Alkylation Of Mono-Alcohols Via Hydrogen Atom Transfer (Hat) Of An Activated Boron-Containing Complex, Courtney Deanna Glenn

Graduate Theses, Dissertations, and Problem Reports

Hydroxy (-OH) groups are one of the most abundant functional groups found in natural products and pharmaceuticals with many of these compounds containing multiple alcohol classes. The ability to selectively functionalize a specific α-OH C–H bond in the presence of other competitive sites would provide straightforward access to new, potentially bioactive compounds. In recent literature, photoredox catalysis has been implemented to perform site and stereoselective α-OH C–H functionalization of cis-diol containing substrates. Incorporating an organoboron cocatalyst into these systems have proven to be crucial in decreasing the bond dissociation energy (BDE) and increasing hydricity of the α-OH C–H bond …

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Real-Time Spectroscopic Ellipsometry For Flux Calibrations In Multi-Source Co-Evaporation Of Thin Films: Application To Rate Variations In Cuinse₂ Deposition, Dhurba R. Sapkota, Balaji Ramanujam, Puja Pradhan, Mohammed A. Razooqi Alaani, Ambalanath Shan, Michael J. Heben, Sylvain Marsillac, Nikolas J. Podraza, Robert W. Collins Jan 2024

Real-Time Spectroscopic Ellipsometry For Flux Calibrations In Multi-Source Co-Evaporation Of Thin Films: Application To Rate Variations In Cuinse₂ Deposition, Dhurba R. Sapkota, Balaji Ramanujam, Puja Pradhan, Mohammed A. Razooqi Alaani, Ambalanath Shan, Michael J. Heben, Sylvain Marsillac, Nikolas J. Podraza, Robert W. Collins

Electrical & Computer Engineering Faculty Publications

Flux calibrations in multi-source thermal co-evaporation of thin films have been developed based on real-time spectroscopic ellipsometry (RTSE) measurements. This methodology has been applied to fabricate CuInSe2 (CIS) thin film photovoltaic (PV) absorbers, as an illustrative example, and their properties as functions of deposition rate have been studied. In this example, multiple Cu layers are deposited step-wise onto the same Si wafer substrate at different Cu evaporation source temperatures (TCu). Multiple In2Se3 layers are deposited similarly at different In source temperatures (TIn). Using RTSE, the Cu and In2Se3 deposition rates are determined as …

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Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi Jan 2024

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi

Chemistry & Biochemistry Faculty Publications

We investigate switching of photoluminescence (PL) from PbS quantum dots (QDs) crosslinked with two different types of photochromic diarylethene molecules, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (1H) and 4,4'-(1-perfluorocyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (2F). Our results show that the QDs crosslinked with the hydrogenated molecule (1H) exhibit a greater amount of switching in photoluminescence intensity compared to QDs crosslinked with the fluorinated molecule (2F). With a combination of differential pulse voltammetry and density functional theory, we attribute the different amount of PL switching to the different energy levels between 1H and 2F molecules which result in different potential barrier …

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