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Geochemical Assessment Of Sediment Flux In A Sediment Core From A Tidal Flat In A Tropical Estuary, Olumide Ajulo

Master's Theses or Doctor of Nursing Practice

Sediment flux in estuaries is influenced by both natural processes and anthropogenic activities. Understanding the historical and current trends in sediment flux inputs and geochemical composition are essential for evaluating the estuary’s response to natural and human-induced changes and for developing effective environmental management strategies. The tropical Wouri Estuary in Cameroon receives water and sediment inputs from three main rivers draining urban, industrial, and agricultural areas, as well as different rock terrains. The complex inputs into the estuary can significantly affect sediment flux, consequently impacting the ecosystem. Thereby making an understanding of the temporal variations in sediment inputs in the …

The Relationship Between Pillar[5]Arene And Pillar[6]Arene In The Synthetic Route To A Water-Soluble Pillar[6]Arene: A Case Of Kinetic And Thermodynamic Products Or Two Distinct, Competing Reactions, Helice A. Gillis

Open Access Dissertations

Pillar[n]arenes, discovered in 2008, have already made their mark as a formidable addition to the field of supramolecular chemistry, largely due to their host-guest chemistry. While the synthesis of pillar[5]arene is well established, the synthesis of pillar[6]arene, with its larger core, has not been so straightforward and mainly accomplished through the use of bulky solvents. Here we present an optimized method for a reproducible, acid-catalyzed synthesis for a brominated pillar[6]arene, starting with a brominated monomer and using chloroform as the templating solvent. Our studies have demonstrated the ratio of brominated pillar[6]arene to brominated pillar[5]arene increases with both decreasing concentration of …

Probing Biomolecular Structure And Dynamics Via Infrared Action Spectroscopy, Madeline Schultz

Open Access Dissertations

Biomolecular structure is supported by a network of inter- and intramolecular interactions, which can be inherently complex in the condensed phase. Isolating biomolecules from the condensed phase to vacuum, via electrospray ionization (ESI), can afford precise control over experimental conditions, yielding additional structural insight. However, the loss of solvation inherent to the ESI process can drive structural rearrangement, particularly at charge sites.

Microsolvation reagents can be used to partially mimic the solvation of charged moieties in solution as they are brought into the gas phase through complexation. This serves two primary functions: 1) reducing propensity for structural rearrangement of systems …

Characterization Of Methodological Variability In Compound Specific Isotope Analysis Of Amino Acids (Csia-Aa), Audreyana Brown-Nash

Open Access Dissertations

The use of isotopes in the natural sciences stems from the principle that chemical reactions predictably alter the isotopic composition of a given sample. Recent advances in compound specific isotope analysis of amino acids (CSIA-AA) have paved the way for studies of increasingly complex ecological relationships, including the identification and characterization of organismal physiology, consumer-resource linkages, biogeochemical cycling, and movement ecology. The analytical power of CSIA-AA has caused an exponential increase in the number of application-based studies since its inception in the 1990s. With the technique constantly evolving to accommodate new research goals, it is important to understand how variation …

Towards Developing Glut2 Specific Probes For Biochemical And Biomedical Applications, Abdelrahman Ismail

Dissertations, Master's Theses and Master's Reports

Facilitated Glucose transporters (GLUTs) are membrane proteins responsible for the uptake of simple sugars and other structurally similar metabolites in all mammalian cells. One of the hallmarks of cancer is dysfunctional sugar metabolism, known as the Warburg effect, and one of the manifestations of that effect is abnormal GLUT expression. There are 14 known GLUT proteins with different expression patterns in different tissues, and tumors tend to express certain GLUTs that are not present in surrounding healthy tissue. Therefore, selective targeting of GLUTs presents a potentially powerful tool for diagnostics and treatment of cancer and other diseases. This has been …

Microwave Assisted Syntheses And Characterizations Of Near-Infrared Ratiometric Probes For Mitochondrial Ph Detection And Monitoring, Ronald J. Schwandt

Dissertations, Master's Theses and Master's Reports

Within the field of biochemistry, there has been a significant development of ratiometric fluorescent probes designed for mitochondrial pH detection; however, many of these probes have emissions within the visible spectrum and require long synthesis times with low-yield reactions. However, in recent years, microwave-assisted syntheses of organic molecules have led to significant increases in reaction yields and quicker reaction times. In this work, two common reactions in probe synthesis, Heck coupling, and Knoevenagel condensations are investigated using microwave-assisted synthesis. It was found the low-concentration Heck coupling reactions using palladium (II) acetate led to extremely efficient Heck coupling. Also, a novel …

Development Of Near-Infrared Probe For The Detection Of Nadh And Nad(P)H In Live Cells And D. Melanogaster Larvae, Sophia J. Jaeger

Dissertations, Master's Theses and Master's Reports

A near-infrared fluorescent probe, A, was designed by substituting the carbonyl group of the coumarin dye’s lactone with a 4-cyano-1-methylpyridinium methylene group and then attaching an electron-withdrawing NADH-sensing methylquinolinium acceptor via a vinyl bond linkage to the coumarin dye at the 4-position. The probe exhibits primary absorption maxima at 603, 428, and 361 nm, and fluoresces weakly at 703 nm. The addition of NAD(P)H results in a significant blue shift in the fluorescence peak from 703 to 670 nm, accompanied an increase in fluorescence intensity. This spectral shift is attributed to the transformation of A−π–A−π–D configuration to D−π–A−π–D pyridinium platform …

Multiscale Computational Chemistry Studies Of The Catalytic Mechanisms Of Non-Heme Fe(Ii)/2-Oxoglutarate-Dependent Oxygenases, Simahudeen Bathir Jaber Sathik Rifayee

Dissertations, Master's Theses and Master's Reports

Enzymes catalyze complex biological transformations. Non-heme Fe(II)/2-oxoglutarate (2OG)–dependent enzymes are highly versatile catalysts capable of selective C–H oxidation, enabling transformations such as hydroxylation, halogenation, desaturation, demethylation, ring rearrangements, epoxidation, and electrophilic aromatic substitution. These enzymes are involved in various biological processes, including fatty acid metabolism, hypoxic signaling, collagen maturation, and transcriptional regulation. Computational Modeling provides detailed knowledge of the enzymes including atomistic details of the important catalytic species, conformational and electronic effects, which are crucial to enzyme engineering and drug design efforts. This dissertation implements advanced multi-scale molecular modelling techniques including Molecular dynamics and Quantum Mechanic / Molecular Mechanics calculations …

Valorizing Municipal Solid Waste For Sustainable Aviation Fuel And Polyhydroxyalkanoate Bioplastics: Pyrolysis And Microbial Pathways, Emon Das

Theses and Dissertations--Biosystems and Agricultural Engineering

The escalating global burden of municipal solid waste (MSW), projected to reach 3.88 billion tons annually by 2050, calls for innovative valorization strategies to mitigate environmental impacts and promote a circular bioeconomy. This thesis investigates the conversion of MSW into two high-value products: sustainable aviation fuel (SAF) and polyhydroxyalkanoate (PHA) bioplastics. Chapter one presents comprehensive physicochemical characterization and pyrolysis-GC/MS analysis of MSW feedstocks. The physicochemical results reveal that densification enhances handling and storage properties, while pyrolysis-GC/MS analysis indicates that plastic-rich MSW streams produce bio-oils with favorable hydrocarbon profiles suitable for SAF production, potentially contributing to decarbonization efforts in the aviation …

The Chemical Nature Of Colors, Bryant Corbin, Bryant Corbin

Longwood Senior Thesis Proposal

No abstract provided.

Advances In Bacterial Cellulose-Based Scaffolds For Tissue Engineering: Review, Rewati Raman Ujjwal, Gymama Slaughter

Center for Bioelectronics Publications

Bacterial cellulose (BC) has emerged as a highly versatile and promising biomaterial in tissue engineering, with potential applications across skin, bone, cartilage, and vascular regeneration. Its exceptional properties like high mechanical strength, superior biocompatibility, excellent moisture retention, and inherent ability to support cell adhesion and proliferation, make BC particularly effective for wound healing and skin regeneration. These attributes accelerate tissue repair and foster new tissue formation, highlighting its value in skin-related applications. Additionally, BC's capacity to support osteogenic differentiation, combined with its mechanical robustness, positions it as a strong candidate for bone tissue engineering, facilitating regeneration and repair. Recent advancements …

Generational Exposures To Cerium Oxide Nanoparticles And Perfluorooctanesulfonic Acid Affect The Performance Of Daughter Plants, Preston Clubb

Graduate Theses/Dissertations

The effects of parental stress on the performance of next generation exposed to another contaminant were investigated. Wheat was exposed to cerium oxide nanoparticles (CeO2-NPs) in first and second generations and exposed to perfluorooctanesulfonic acid (PFOS) in the third generation. Phenotypic or metabolic responses were assessed at 21-day (short-term exposure) or 90-day (long-term exposure) exposure periods. Biomass production, chlorophyll content, enzyme activity, and membrane damage were measured at short-term exposure, while elemental and PFOS concentrations, and grain metabolites were analyzed in long-term exposure. Results showed that continued exposures to CeO2-NPs and PFOS enhanced chlorophyll content but reduced concentrations of important …

Perceptions, Efficacy, And Adaptation Of Online Learning In Physics And Chemistry Education, Fun Man Fung, Jia Yi Han, Min Xin Pua

Journal of Educational Technology Development and Exchange (JETDE)

The COVID-19 pandemic forced a sudden shift to online learning in Physics and Chemistry in Singapore. As restrictions eased, researchers explored its impact through interviews with instructors and analysis of student data made available through a data lake managed by the National University of Singapore’s Institute for Applied Learning Sciences and Educational Technology. Interviews focused on instructor adaptation and beliefs about online teaching, while the data investigated student perceptions and changes in teaching efficacy pre- and post-pandemic. Analysis of the students’ course feedback indicated that Course Code C005 received more positive feedback from students, particularly towards the instructor’s effectiveness in …

Open Path Spectroscopic Detection Of The Hydroxyl Radical: A Comparison Between Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas) And Bbceas Coupled With A Fabry-Pérot Interferometer (Bbceas-Fp), Callum Flowerday, Ryan Thalman, Matthew C. Asplund, Samuel A. Badstubner, Adam K. Cook, Philip Lundrigan, Jaron C. Hansen

ScholarsArchive Data

Data collected by the BBCEAS and BBCEAS-FP instruments described in the paper "Open Path Spectroscopic Detection of the Hydroxyl Radical: A Comparison Between Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) and BBCEAS coupled with a Fabry-Pérot Interferometer (BBCEAS-FP)"

Investigation Of Colorimetric Trends In Rare-Earth Co-Doped Ypo₄, Barit K. Essman

All Master's Theses

From detectors in scientific instrumentation to medical imaging devices and nuclear monitoring systems to LEDs seen in consumer products, phosphors are utilized in a myriad of applications experienced by both the general public and scientific community alike. For many phosphor applications, emission color and intensity are notably important features to consider. When phosphors are co-doped with rare-earth activators, the ability to predict emission intensity and color output becomes challenging due to competition kinetics and energy transfer between the dopants. During this study, correlation between trends in co-doped phosphor excitation and color output were analyzed to interpret optical behaviors originating from …

Phytochemistry Of Dalea Candida Var. Oligophylla, Ryan E. Galperin

All Master's Theses

The focus of this project was the plant Dalea candida and its phytochemistry. The plant compounds were isolated and purified by an array of chromatographic techniques. The structures of the pure compounds were determined by one-dimensional and two-dimensional ¹H and ¹³C NMR spectroscopy, supported by infrared and ultraviolet spectroscopy, experimental and calculated circular dichroism spectroscopy, and mass spectrometry. Plant parts were worked on separately since they typically differ in content. Purified compounds will be tested for biological activities. Based on our results, eight new or known compound were isolated, specifically four new compounds and four known compounds. Compound …

A Colorimetric Sensor Array For Differentiating Emerging Material Contaminants Based On Surface Chemistry, Ifunanya Chiamaka Ede

All Master's Theses

Emerging materials contaminants, such as microplastics (MPs) and engineered nanoparticles (ENPs), are now recognized to contaminate oceans, seas, freshwater, and drinking water through many different exposure pathways. The extent of the materials' water contamination problem has only begun to be properly appreciated in the last decade. While comprehensive global data on the exact quantity of nano- and microcontaminants in drinking water is challenging to ascertain, studies have shown that microplastics and nanoparticles can now be found in drinking water sources worldwide.  Indeed, a well-publicized recent study has shown that 93% of bottled water around the world contains microplastic contamination.

Detecting …

One Peak, Two Peaks: On The Effects Of Enhanced Evaporation In An Ammonium Sulfate And Succinic Acid Aerosol System, Julia Reynolds

Honors Theses

Aerosols, defined as suspensions of liquid or solid particles in a gaseous medium, are ubiquitous in both indoor and outdoor environments. They have significant impacts ranging from public health concerns to climate dynamics. In laboratory settings, aerosols are most often generated through a technique known as atomization. The atomization or nebulization is from dilute, aqueous solutions of various chemical compositions. This process typically produces a unimodal, lognormal particle size distribution with exceedingly rare exceptions. Colleagues in a different laboratory (Dr. Freedman’s Group at Pennsylvania State University), however, mentioned they observed a bimodal size distribution, a distribution with more than one …

The Effect Of Polyethylene Glycol Surface Density Of Dense Brush Gold Nanoparticles On Insulin Fibrillation, Ethan Patrick Grier

Graduate Theses/Dissertations

The development of various neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease has been linked to the fibrillation of various proteins within the brain. Parkinson’s disease is specifically linked to the fibrillation of α-Synuclein. During the fibrillation process, the proteins take the form of oligomers, and exposure to these oligomers has been linked to various cytotoxic and neurotoxic effects. Once the fibrillation process is complete, the fibrils made have been shown to be much less toxic than the oligomer stage. This fibrillation process is thermodynamically favorable and is largely irreversible, so one course of action for treatment of these …

Removal Of Antibiotics Under Visible Light By Using C,N-Tio2 Incorporated Into Magnetite Mesoporous Silica Composites, Dwita Widyawati

Chulalongkorn University Theses and Dissertations (Chula ETD)

Water contamination, particularly from antibiotics such as ciprofloxacin, is a significant environmental challenge necessitating the development of new remediation solutions. A promising technique for eliminating CIP from the environment is photocatalysis. The synthesis of C,N-doped TiO2 embedded within magnetite mesoporous silica (MSI) composites is prepared to serve as a promising semiconductor catalyst for photodegradation under visible illumination. Tetrabutyl titanate (TBOT), glucose, and urea are used as precursors in the sol-gel synthesis process, which controls elemental ratios to produce a unique mesoporous composite material intended to improve antibiotic photodegradation in the presence of visible light. Comparisons showed significant differences between capped …

Gel Based Sensing Platforms For Ammonia Detection, Patita Salee

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focuses on the development of two biopolymer-based colorimetric platforms for ammonia detection in environmental water and gaseous samples. To detect ammonia in water samples, an agarose hydrogel membrane containing salicylate, hypochlorite, and sodium nitroprusside was incorporated into a flow analysis system to perform the Berthelot reaction within the gel. Ammonium in the sample was converted to monochloramine in an alkaline reagent stream, and its subsequent interaction with the sensing membrane yielded an indosalicylate blue chromophore, causing the gel to change from pale yellow to green–blue as the ammonia concentration increased. Under the optimal operating conditions, the method provided …

Alpha-Synuclein Interaction With Gedunin, Tony Matundura Nyabayo

Graduate Theses/Dissertations

Parkinson’s disease (PD) and other Proteinopathies develop when α-synuclein misfolds and aggregates into toxic amyloids. While existing treatments for PD are primarily focused on managing its symptoms, a viable solution for slowing down the progress of Parkinson’s disease involves targeting the toxic α-synuclein amyloids. Gedunin, a natural inhibitor of heat shock protein 90, has been extensively used to treat malaria. Also, recent research investigations have shed light on its potential beyond malaria therapy, indicating that Gedunin may offer a possible solution for treating a variety of neurodegenerative diseases. Using plate-based assays, we examined how Gedunin influences α-synuclein fibrillation and its …

Lc-Ms Discriminates Between Effects Of Sulfur Nanoparticles Vs Molybdenum Disulfide Nanoparticles On Lettuce (Lactuca Sativa), Mary Fakunle

Graduate Theses/Dissertations

Nanotechnology is gaining attention in agriculture, majorly due to their potential benefits in farming practices. Sulfur and molybdenum disulfide nanoparticles are reported to enhance plant growth, protection, and nutrient delivery. However, there is a need to understand how nano-fertilizers affect the metabolites and nutritional benefits of plants. Here, lettuce was cultivated under greenhouse in one of three treatments: control, 50 ppm S NPs, and 20 ppm MoS2 NPs. A method was developed on Liquid Chromatography – Mass Spectrometry (LC-MS) instrument to quantify the concentration of amino acids and antioxidants in the harvested lettuce plants. Inductively Coupled Plasma – Mass Spectrometry …

Evaluation Of Practical Methods To Determine If A Karst Creek Is Gaining Or Losing: Case Study Of Leith Creek, Elizabeth Jones

Graduate Theses/Dissertations

Karst landscapes are abundant in Missouri, with features such as caves, springs, and sinkholes that form through the dissolution of limestone. Leith Creek is a small stream in Polk County, Missouri fed by two springs and the shallow unconfined Springfield Plateau aquifer, a highly karstified aquifer which is made up of limestone and minor interbedded shale-mudstone units. To determine if Leith Creek is gaining or losing, stream flow, water chemistry and temperature sensors were monitored. Stream flow results required multiple visits to take measurements while temperature sensors required two visits, one to install the dataloggers and another to remove the …

Development Of Cyan And Blue Thermostable Fluorescent Proteins: Characterization And Structural Analysis, Acacia J. Jurkowski

Graduate Theses/Dissertations

Fluorescent proteins are commonly used as cell markers in living organisms. Modifications by mutation can be used to improve the qualities of these proteins including fluorescence, thermostability, pH stability, and chemical stability. The goal of this project is to use mutagenesis to improve the fluorescence of thermostable cyan and blue proteins derived from the thermal green protein (TGP). The first cyan protein developed by the DeVore lab (CTP 0.0) shifted the fluorescence to cyan but decreased the quantum yield (Φ_F) to 0.056. Further mutations were incorporated to increase the quantum yield through incorporating hydrogen bonding interactions to the …

Effects Of Chain Length, Saturation, And Bases On Saponification, Sarah Fenik

Williams Honors College, Honors Research Projects

This project will analyze the effects of chain length and saturation of fatty acids on saponification processes, as well as the effects of the base used in the reaction. Stearic acid, lauric acid, and oleic acid will be used for the fatty acid comparisons, and sodium hydroxide and potassium hydroxide will be used for the base comparisons. Stearic acid is considered a long chain fatty acid, while lauric acid is considered a short chain fatty acid. Oleic acid is a monounsaturated fatty acid. Five soap products are be made: sodium stearate, sodium laurate, sodium oleate, potassium stearate, and potassium oleate. …

Synthesis Of Noval Hydroxy Chalcone And Study Of Fluorescent Properties, Margaret Hilliker

Williams Honors College, Honors Research Projects

Chalcones are a class of naturally occurring compounds found in plants, which have a general structure of Ar–CO–CH=CH–Ar’. They have shown significant potential as tunable organic fluorophores due to their extended π-conjugation and structural simplicity. In this study, a 2-hydroxy-substituted chalcone featuring a terminal dimethylamino group was synthesized via a pyrrolidine-catalyzed aldol condensation and characterized for its photophysical properties. The electron-donating and -accepting ends of the molecule establish an intramolecular charge transfer (ICT) pathway, while the hydroxyl group enables excited state intramolecular proton transfer (ESIPT), leading to complex emission behavior. Room temperature fluorescence analysis revealed broad, featureless emission, while low-temperature …

Interaction Of Cardiac Leiomodin With The Native Cardiac Thin Filament, Madison Little, Cristina M. Risi, Tania M. Larrinaga, Mason D. Summers, Tyler Nguyen, Garry E. Smith Jr., Jennifer Atherton, Carol C. Gregorio, Alla S. Kostyukova, Vitold E. Galkin

Department of Biomedical and Translational Sciences Faculty Publications

Every heartbeat depends on cyclical contraction-relaxation produced by the interactions between myosin-containing thick and actin-based thin filaments (TFs) arranged into a crystalline-like lattice in the cardiac sarcomere. Therefore, the maintenance of thin filament length is crucial for myocardium function. The thin filament is comprised of an actin backbone, the regulatory troponin complex and tropomyosin that controls interactions between thick and thin filaments. Thin filament length is controlled by the tropomodulin family of proteins; tropomodulin caps pointed ends of thin filaments, and leiomodin (Lmod) promotes elongation of thin filaments by a “leaky-cap” mechanism. The broader distribution of Lmod on the thin …

Structural Optimization And Stability Enhancement Of Uba(2) And Ntl9 Using The Computational Tool: Emcast, Bahar Ghazi Esfahani

Graduate Student Theses, Dissertations, & Professional Papers

This study enhances protein stability prediction by refining EmCAST (Empirical C-Alpha Stability Tool), a computational tool used to identify stabilizing mutations in protein domains. We applied EmCAST to two model proteins: the α-helical ubiquitin-associated domain 2 (UBA(2)) and the α/β N-terminal domain of ribosomal protein L9 (NTL9). Protein stability is critical for proper function, and mutations can lead to misfolding and disease. To validate EmCAST’s predictions, guanidine hydrochloride-induced denaturation was monitored using circular dichroism (CD) spectroscopy for both wild-type and mutant variants. Results guided refinements to EmCAST’s algorithm, incorporating new experimental datasets to improve accuracy. Additionally, we examined the assumption …

Near-Infrared Fluorescent Cyanine Probes For Monitoring Nad(P)H Dynamics In Living Cells And Drosophila Larvae, May Waters

Dissertations, Master's Theses and Master's Reports

Nicotinamide adenine dinucleotide (NAD+/NADH) plays a critical role in cellular metabolism, with abnormally elevated NADH levels linked to disrupted metabolic processes and cancer. In this study, we developed near-infrared fluorescent probes to selectively measure NADH concentrations. We present five cyanine-based probes, which were optimized by modifying the connection bridges to fine tune electronics. Two NAD(P)H-biosensing probes consisting of 1,3,3-trimethyl-3H-indolium and 3-quinolinium acceptors, linked by thiophene, A, and 3,4-ethylenedioxythiophene, B, bridges are detailed. They exhibit near-infrared fluorescence at 742.1 nm and 727.2 nm for probes A and B, respectively, and generate absorbance signals at 690.6 nm and 685.9 nm. Probe A …