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Articles 301 - 330 of 15524
Full-Text Articles in Entire DC Network
Optimized Co2 Gas Sensing With Sns:Sm2o3/N-Si Nanocomposites Fabricated Via Spray Pyrolysis, Wasan A. Khalaf, Mays A. Hammadi, Mohammed J. Alsultani, Yahya R. Hathal, Mohammed O. Salman
Optimized Co2 Gas Sensing With Sns:Sm2o3/N-Si Nanocomposites Fabricated Via Spray Pyrolysis, Wasan A. Khalaf, Mays A. Hammadi, Mohammed J. Alsultani, Yahya R. Hathal, Mohammed O. Salman
Karbala International Journal of Modern Science
In this work, tin sulfide:samarium oxide (SnS:Sm2O3) composite films were deposited using a spray pyrolysis technique for room-temperature CO2 gas sensing. X-ray diffraction (XRD) confirmed a polycrystalline SnS nature of orthorhombic-phase crystallinity at 10 at.% Sm ions, while 20 at.% Sm induced Sm2O3 as a separate phase. Field emission-scanning electron microscopy (FE-SEM) induced uniform grains and increased the surface roughness, enhancing gas adsorption. UV-visible absorbance revealed band-gap narrowing. Fourier transform infrared spectroscopy (FTIR) analysis revealed vibrational band shifts, confirming the structural modifications. Gas-sensing measurements demonstrated 5.72%, 19.65%, and 9.65% for pure SnS, …
Structural Characterization Of Peptide Nanoaggregates At Varying Concentrations And Their Impact On Cellular Responses, Malika Rozmetova
Structural Characterization Of Peptide Nanoaggregates At Varying Concentrations And Their Impact On Cellular Responses, Malika Rozmetova
Theses and Dissertations
Peptide nano-assemblies can regulate cellular pathways in a structure-dependent manner. Here, we show that the enzyme-responsive peptide NapFFK(NBD)Yp forms distinct nanoscale assemblies at different concentrations, triggering differential ER stress and extracellular vesicle release in MDA-MB231 cells. These results highlight the importance of supramolecular organization in peptide–cell interactions.
Flux Crystal Growth Of Potassium Lanthanide Double Vanadates With Lanthanide-Dependent Coordination Number Variance, Hunter B. Tisdale, Hans Conrad Zur Loye
Flux Crystal Growth Of Potassium Lanthanide Double Vanadates With Lanthanide-Dependent Coordination Number Variance, Hunter B. Tisdale, Hans Conrad Zur Loye
Faculty Publications
A series of potassium rare earth double vanadates is presented. Single crystals of double vanadates with stoichiometry K3Ln(VO4)2 (Ln = La, Pr, Nd, and Sm) and crystallizing in the glaserite structure type were synthesized via a molten alkali chloride/fluoride flux reaction. Different structures were observed depending on the constituent rare earth: K3La(VO4)2 crystallizes in an as-of-yet unreported modification of the typical glaserite structure in the space group P21/c, likely due to its larger ionic size that results in an increase in the lanthanide coordination number …
Iron(Ii)/Cobalt(Ii)-Mediated Silicon And Carbon Quantum Dots For Nanozyme Activity And Fluorescence Sensing Of Hydrogen Peroxide And Glucose, Kang Qin
Dissertations and Theses
Silicon quantum dots (SiQDs) and carbon quantum dots (CQDs) have been widely studied as fluorescent nanomaterials for sensing applications. In this thesis, we developed two different nanomaterials, SiQDs and CQDs, and investigated their catalytic activities and applied them for the detection of hydrogen peroxide and glucose. In the first project, Co2+-mediated SiQDs were synthesized through a hydrothermal method. The obtained nanoparticles showed obvious peroxidase-like activity toward the oxidation of tetramethylbenzidine (TMB) in the presence of H2O2 under acidic conditions. Moreover, a weak oxidation of TMB was also observed without H2O2, suggesting the existence of oxidase-like activity. To better understand the …
Development And Validation Of An Analytical Method For Quantitative Determination Of Small Aldehydes In Plasma, Stephanie T. Clark
Development And Validation Of An Analytical Method For Quantitative Determination Of Small Aldehydes In Plasma, Stephanie T. Clark
Chemistry & Biochemistry Theses - Archive
Small aldehydes such as formaldehyde and acetaldehyde are highly reactive metabolites that play important roles in biological processes related to oxidative stress, metabolism, and DNA damage. Because of their chemical reactivity, volatility, and low endogenous concentrations, accurate measurement of these compounds in biological samples remains analytically challenging. The goal was to develop and evaluate a practical analytical method for detecting small aldehydes in biologically relevant matrices using headspace gas chromatography mass spectrometry (HS-GC-MS). The method combined chemical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and headspace sampling to stabilize aldehydes and enable selective detection by mass spectrometry. Method development focused on optimizing derivatization …
Advancing Lipidomics Through Fluoroalcohol-Induced Multiphase Fractionation And Orthogonal Lc×Lc–Ms Detection, Md Al Amin
Chemistry & Biochemistry Dissertations
Comprehensive characterization of the lipidome remains a significant analytical challenge due to the immense structural diversity, wide dynamic range, and complex physicochemical continuum of lipid species. Conventional extraction methods, such as those by Bligh–Dyer and Folch, and one-dimensional liquid chromatography (1D-LC) often fail to resolve this complexity, leading to chromatographic overlap, severe ion suppression, and limited coverage of low-abundance or highly hydrophobic species. This dissertation addresses these bottlenecks by establishing a separation-driven analytical framework that integrates novel fluoroalcohol-induced multiphase systems (FAiTPS) with orthogonal multidimensional liquid chromatography–mass spectrometry (LC×LC–MS).
The core of this research is the development and physicochemical characterization of …
Reversible Fluorescence Quenching And Recovery In Pvp-Supported Copper Nanoparticles, Sara Rayan
Reversible Fluorescence Quenching And Recovery In Pvp-Supported Copper Nanoparticles, Sara Rayan
Senior Honors Theses and Projects
Copper nanoclusters stabilized by polyvinylpyrrolidone (PVP) exhibit unique fluorescence properties that are highly sensitive to changes in their chemical environment, making them promising candidates for sensing applications. This study investigates the reversible fluorescence quenching and recovery behavior of PVP-supported copper nanoparticles in response to iron(III) ions and evaluates the selectivity of this response across different chemical conditions. Fluorescence quenching was examined using Fe³⁺ introduced as FeCl₃, followed by recovery experiments using ascorbic acid to assess reversibility through redox-driven interactions. To determine whether the observed response is specific to iron, potassium ferricyanide was used as an alternative Fe³⁺ source. Additional comparisons …
Investigating The Effects Of Atg3 On Autophagosome Size And Number, Keeran R. Senthil Kumar
Investigating The Effects Of Atg3 On Autophagosome Size And Number, Keeran R. Senthil Kumar
Senior Honors Theses and Projects
Macroautophagy, or autophagy, is a highly conserved catabolic process in all eukaryotes which allows for the degradation of large cytosolic contents. It occurs in two forms: bulk autophagy, which is induced by nutrient deprivation and targets nonspecific cargo, and selective autophagy, which is induced by cellular stress and sequesters specific substrates. The process of autophagosome formation is carried out by a group of Atg (autophagy-related) proteins, one of which is Atg3. Atg3 functions as an E2-like enzyme by conjugating Atg8 — a ubiquitin-like protein — to phosphatidylethanolamine (PE), a step required for autophagosome membrane formation. This lipidation process is catalyzed …
Efficient Organic Molecular Crystal Structure Prediction Using The Density Functional Tight-Binding Method, Maureen M. Kitheka, Yan Jing, Yan Yao, Puja Goyal
Efficient Organic Molecular Crystal Structure Prediction Using The Density Functional Tight-Binding Method, Maureen M. Kitheka, Yan Jing, Yan Yao, Puja Goyal
Faculty Publications – Chemistry
Over the years, computational crystal structure prediction (CSP) for organic molecules has thrived as an area of research, spanning various scientific disciplines and having significant applications in industries such as pharmaceuticals and agrochemicals. Within the field of batteries, redox-active organic materials (ROMs) such as quinones have received increased attention as promising electrode materials for rechargeable batteries. However, experimental determination of the crystal structure of intermediate species formed during the discharge/charge cycle can often be challenging. Incomplete X-ray diffraction patterns can also lead to difficulties in crystal structure determination for ROMs used in batteries. Use of a semiempirical electronic structure method …
Characterizing The Unique Chemical Imprint Of On-Axis, Lower-Temperature Hydrothermal Flow To The Deep Ocean (Southern East Pacific Rise, 16.5°-18.0°S), Laura E. Moore, Randelle M. Bundy, Joseph A. Resing, Scott White, Tamara Baumberger, Peter N. Sedwick, Nathaniel J. Buck, Anson M. Antriasian, Isaac Keohane, Bettina M. Sohst, Sharon L. Walker, Christopher R. German
Characterizing The Unique Chemical Imprint Of On-Axis, Lower-Temperature Hydrothermal Flow To The Deep Ocean (Southern East Pacific Rise, 16.5°-18.0°S), Laura E. Moore, Randelle M. Bundy, Joseph A. Resing, Scott White, Tamara Baumberger, Peter N. Sedwick, Nathaniel J. Buck, Anson M. Antriasian, Isaac Keohane, Bettina M. Sohst, Sharon L. Walker, Christopher R. German
OES Faculty Publications
In addition to high-temperature vents, lower-temperature flow (LTF) (< 300°C) is abundant along mid-ocean ridges and contributes globally-important fluxes of heat and water along with largely-unconstrained geochemical influences on the ocean. We examined the impact of on-axis LTF on the chemical composition of the overlying water column (< 40 m above seafloor) along the 16.5°-18.0°S sector of the ultrafast-spreading southern East Pacific Rise using autonomous underwater vehicle Sentry surveys and conductivity-temperature-depth rosette casts. LTF sites were typically spatially isolated from high-temperature systems and imparted unique chemical signatures to the overlying ocean. Water column samples impacted by LTF exhibited low particulate iron:sulfur ratios and high methane: total-dissolvable manganese ratios, whereas samples influenced by high-temperature venting exhibited opposite trends. We confirmed that LTF imparts a distinct and measurable chemical signature to the water column, independent from high-temperature vents. Isolated, on-axis LTF will be important to consider when assessing hydrothermal circulation impacts upon ocean biogeochemistry.
Scanning Electron Microscopy As A Potential Tool For Distinguishing Charcoal From Dark, Oxidized, Biomass, João Vitor Dos Santos, Aleksandar I. Goranov, Lais Gomes Fregolente, Joao Marcos De Lima-Faria, Diego Stefani Teodoro Martinez, Patrick G. Hatcher
Scanning Electron Microscopy As A Potential Tool For Distinguishing Charcoal From Dark, Oxidized, Biomass, João Vitor Dos Santos, Aleksandar I. Goranov, Lais Gomes Fregolente, Joao Marcos De Lima-Faria, Diego Stefani Teodoro Martinez, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
Condensed aromatic carbon (ConAC) is widely used as a proxy for organic materials derived from biomass burning. However, recent evidence shows that ConAC can be also formed through nonpyrogenic oxidative processes. This study presents a proof-of-concept investigation using scanning electron microscopy (SEM) to distinguish charcoal from dark, ConAC-rich materials produced by ambient oxidation of biomass. Pine wood exposed to long-term iron-mediated oxidation was compared with unaltered wood and a controlled laboratory-generated charcoal reference. Conventional geochemical analytical methods, including benzenepoly(carboxylic acid) (BPCA) analysis, Fourier transform–ion cyclotron resonance–mass spectrometry (FT-ICR-MS), solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis, confirmed substantial …
Flow Injection Determination Of Fluoride For Total Organic Fluorine Analysis, Memona Zulafiqar
Flow Injection Determination Of Fluoride For Total Organic Fluorine Analysis, Memona Zulafiqar
Chemistry & Biochemistry Theses
Poly- and perfluoroalkyl substances (PFAS) are anthropogenic chemicals that have gained increasing attention due to their association with a wide range of adverse health effects. These compounds are highly diverse, with approximately 15,000 PFAS reported. Their exceptional environmental stability and strong tendency to bioaccumulate result in environmentally relevant concentrations that typically occur at very low levels, often in the ng L⁻¹ range. This chemical diversity presents a major analytical challenge, as reference standards are available for only a limited number of PFAS. Consequently, conventional targeted analytical methods frequently quantify less than 1% of the total PFAS present, leading to a …
Asymmetric Synthesis Of The Hiv Protease Inhibitor Tmc-126, A Pmx Antimalarial Protease Inhibitor, And A Putative Covid-19 Inhibitor Using A Highly Stereoselective Glycolate Aldol Addition Reaction Pathway, Kweku Amaning Affram, Austin Carter, April Breede, Alexandra Kimsey, Godson Hemeson, Bader Semakieh, Moses Martinez, Emmanuel Ayim, Joy Odeh, Shawn R. Hitchcock
Asymmetric Synthesis Of The Hiv Protease Inhibitor Tmc-126, A Pmx Antimalarial Protease Inhibitor, And A Putative Covid-19 Inhibitor Using A Highly Stereoselective Glycolate Aldol Addition Reaction Pathway, Kweku Amaning Affram, Austin Carter, April Breede, Alexandra Kimsey, Godson Hemeson, Bader Semakieh, Moses Martinez, Emmanuel Ayim, Joy Odeh, Shawn R. Hitchcock
Faculty Publications – Chemistry
An asymmetric glycolate aldol addition pathway was developed for the synthetic preparation of a series of protease inhibitors based on the hydroxyethylamine structural motif. A single glycolate aldol adduct derived from a highly diastereoselective (≥95:5 d.r.) asymmetric aldol reaction served as the starting point for the synthesis of the inhibitors. The starting material is easily prepared and purified via recrystallization on multigram scales. This work describes the synthesis of the HIV protease inhibitor TMC-126, the Plasmepsin X (PMX) inhibitor 49c for the treatment of malaria, and a computationally derived inhibitor for the 3CLpro of the SARS-CoV-2 from a single common …
Scope Of Microbial Transglutaminase For Site-Specific And Oriented Immobilization Of Native Antibodies From Various Host Species, Emily Beitello, Kwame Osei, Faith E. Breausche, Jon A. Friesen, Jeremy D. Driskell
Scope Of Microbial Transglutaminase For Site-Specific And Oriented Immobilization Of Native Antibodies From Various Host Species, Emily Beitello, Kwame Osei, Faith E. Breausche, Jon A. Friesen, Jeremy D. Driskell
Faculty Publications – Chemistry
Modification of antibodies to chemically couple labels or immobilization reagents is essential for developing biosensors. Typically, conjugation occurs through chemical methods that leverage reactive amines and thiols on native antibodies; however, this nonspecific approach can interfere with antibody function. Microbial transglutaminase (mTG) is an enzyme that has been used for site-specific conjugation of chemical modifiers to the Fc region of native antibodies, but thus far mTG-mediated conjugation has been limited to production of antibody-drug conjugates with human IgGs. Here, we assessed the scope and versatility of mTG to target IgGs, with the goal of site-specific conjugation to facilitate oriented …
Exploring The Limitations Of Substrate Scope In Dimethylallyltryptophan Synthases, Evan T. Miller
Exploring The Limitations Of Substrate Scope In Dimethylallyltryptophan Synthases, Evan T. Miller
Theses and Dissertations--Pharmacy
Natural products (NPs), are the largest source of bioactive compounds in Nature, and are essential to the treatment of human disease. Nearly 50% of drugs approved for use from 1981 to 2019 owe some aspect of their development to NPs, either in terms of their structure, pharmacophore, or mechanism of action. However, NPs are difficult to structurally optimize. Chemoenzymatic methods for NP derivatization have been increasingly seen as practical alternatives to traditional synthetic methods. Prenyltransferases (PTs) are involved in the primary and secondary metabolism of plants, bacteria, and fungi, and they are key enzymes in the biosynthesis of many clinically …
Investigations Toward A Unified Reaction Pathway Of Thermal And Tbsotf-Mediated Oxidopyrylium-Alkene (5 + 2) Cycloadditions, Adam J. Youman, Samantha N. Rokey, Wentao Guo, Jacob P. Grabowski, Susanna N. Angles, Jacob J. Bulandr, Qing Sun, John R. Goodell, Dean J. Tantillo, T. Andrew Mitchell
Investigations Toward A Unified Reaction Pathway Of Thermal And Tbsotf-Mediated Oxidopyrylium-Alkene (5 + 2) Cycloadditions, Adam J. Youman, Samantha N. Rokey, Wentao Guo, Jacob P. Grabowski, Susanna N. Angles, Jacob J. Bulandr, Qing Sun, John R. Goodell, Dean J. Tantillo, T. Andrew Mitchell
Faculty Publications – Chemistry
Oxidopyrylium-based (5 + 2) cycloadditions are crucial reactions to construct seven-membered carbocycles containing an ether bridge (i.e. oxabicyclo[3.2.1]octanes). Intramolecular silyloxypyrone-based (5 + 2) cycloadditions were investigated and revealed several features: (1) the TBDPS thermal process proceeds via a zwitterionic oxidopyrylium intermediate similar to previously reported TBS variants; (2) the TBSOTf-mediated reaction proceeds through a cationic oxidopyrylium intermediate; (3) quantum chemical calculations predict a stepwise process for an electron-rich dipolarophile for each set of conditions. The thermal silyloxypyrone-based (5 + 2) cycloadditions were extremely dependent on the nature of the dipolarophile and the silyl transfer group. The TBDPS enhances the …
A Bioinspired Approach For Adaptive Solid-Solid Phase Change Material Coatings With Optimized Surface Features For Passive Thermal Regulation, Rajae Bousselham, Zhiying Xiao, Mingjiang Tao, Sergio Granados-Focil, Adriana Hera, Steven Van Dessel
A Bioinspired Approach For Adaptive Solid-Solid Phase Change Material Coatings With Optimized Surface Features For Passive Thermal Regulation, Rajae Bousselham, Zhiying Xiao, Mingjiang Tao, Sergio Granados-Focil, Adriana Hera, Steven Van Dessel
Chemistry
The necessity to reduce global energy consumption calls for innovative strategies in building thermal management. Passive thermal regulation, particularly through bio-inspired designs, offers a promising avenue by mimicking nature's efficient control of optical properties. This research introduces a novel, climate-responsive coating that integrates optimized bio-inspired surface features with a solid-solid phase change material (SS-PCM) to dynamically manage solar absorptivity without adding additional thickness, enabling both heating and cooling as needed. Drawing on the photonic architectures of the Saharan silver ant and Morpho Didius butterfly, we employed a modeling and multi-objective optimization framework to tailor these surface features. Simulations reveal that …
Theoretical Study Of Long-Range Molecular Interactions, Adrian Luis Batista-Planas
Theoretical Study Of Long-Range Molecular Interactions, Adrian Luis Batista-Planas
Doctoral Dissertations
Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions—with electrostatic, induction, and dispersion as main components—play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well-established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed Long-Range-Fit (LRF), an interactive and user-friendly software package designed to automate …
Biochemical Investigations Of F420-Dependent Glucose-6-Phosphate Dehydrogenase From Cryptosporangium Arvum, Sarah T. Al-Noubani
Biochemical Investigations Of F420-Dependent Glucose-6-Phosphate Dehydrogenase From Cryptosporangium Arvum, Sarah T. Al-Noubani
2026 Spring Honors Capstones Projects
F420-dependent glucose-6-phosphate dehydrogenase (FGD) catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconolactone using the deazaflavin, Cofactor F420. FGD from Mycobacterium tuberculosis has been investigated due to its health relevance to prodrug activation. More recently, FGD from Cryptosporangium arvum (Cryar- FGD) has been investigated due to its broader substrate specificity toward multiple sugar phosphates. Kinetic and NMR studies have shown that Cryar-FGD has dual catalytic activity as a dehydrogenase and isomerase. Further investigations are being conducted on Cryar-FGD to characterize key residues involved in catalysis.
To investigate the catalytically active residues of Cryar-FGD, …
Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski
Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski
Chemistry & Biochemistry Faculty Publications
The marine labile dissolved organic carbon (DOC) pool is a dynamic reservoir of thousands of molecules that cycles approximately one-quarter of Earth’s primary production within days to weeks. After excretion by phytoplankton and other microbes, metabolites are rapidly consumed, resulting in low standing concentrations (picomolar to low nanomolar). Despite the decades-long search for labile DOC sources and molecular identities, marine phytoplankton exometabolomes are not well characterized, largely due to difficulties in measuring small polar molecules in saline water. Here, we profiled the exometabolomes of six axenic phytoplankton species representing key functional groups including a diatom (Thalassiosira pseudonana CCMP1335), a …
Expanded Scorpionate And Siderophore-Inspired Ligands: From Foundational Designs To Modern Applications, Austin Winfield Medley, Trandon Allen Bender
Expanded Scorpionate And Siderophore-Inspired Ligands: From Foundational Designs To Modern Applications, Austin Winfield Medley, Trandon Allen Bender
Chemistry & Biochemistry Faculty Publications
Scorpionate ligands have been advanced significantly through systematic modifications of their apical atoms and heterocyclic arms, expanding their structural diversity and chemical reactivity. Recent biologically inspired variants now enable accurate modeling of complex bioinorganic motifs, such as the Fe₄S₄ clusters of nitrogenase, and support enzyme‐like reactivity under mild aqueous conditions. These developments have broadened the impact of scorpionate chemistry across bioinorganic modeling, homogeneous catalysis, and biorthogonal transformations. In particular, expanded tripodal scaffolds provide modular, tunable platforms for mimicking enzyme active sites and probing biological nitrogen fixation pathways. Beyond fundamental insight, these ligands present practical opportunities for sustainable catalysis by enabling …
Sulfhydryl-Functionalized Diarylethenes: Synthesis, Photoswitching, And Fluorescent Properties, Pramod Aryal, Jonathan Bietsch, Gowri Sankar Grandhi, Josh Choi, Guijun Wang
Sulfhydryl-Functionalized Diarylethenes: Synthesis, Photoswitching, And Fluorescent Properties, Pramod Aryal, Jonathan Bietsch, Gowri Sankar Grandhi, Josh Choi, Guijun Wang
Chemistry & Biochemistry Faculty Publications
Sulfhydryl group (SH) plays important roles in reactions with various functional groups, especially in biologically active systems. Photoswitchable diarylethene (DAE) derivatives have demonstrated applications in many research fields. Among the many classes of diarylethene derivatives, thiol derivatives have not been extensively explored. In this study, we systematically synthesized and characterized a series of bis-thiol functionalized dithienylethene derivatives. The thiol groups in this series are attached directly to the thiophene, or through a phenyl or methylene linker. Each series incorporated both dithienyl cyclopentene and hexafluorocyclopentene bridges and total six thiol substituted diarylethenes were synthesized. Among the six sulfhydryl DAE derivatives, four …
Nonpyrogenic "Black" Nitrogen Likely Plays A Major Yet Underrecognized Role In The Global Nitrogen Cycle, João Vitor Dos Santos, Aleksandar I. Goranov, Kyle M. Lambert, Theodoro Da Rosa Salles, Susan J. Carter, Ann Pearson, Patrick G. Hatcher
Nonpyrogenic "Black" Nitrogen Likely Plays A Major Yet Underrecognized Role In The Global Nitrogen Cycle, João Vitor Dos Santos, Aleksandar I. Goranov, Kyle M. Lambert, Theodoro Da Rosa Salles, Susan J. Carter, Ann Pearson, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
Condensed aromatic nitrogen (ConAN) is commonly found in soil and aquatic environments. ConAN is broadly viewed by the biogeochemistry community as a combustion-derived product leading to its frequent designation as pyrogenic “black” nitrogen. Here, we provide evidence that ConAN can also form through nonpyrogenic pathways. In an experiment simulating biomass oxidation, pine wood boards assembled with iron nails were exposed to 12 years of natural environmental conditions. Nitrogen concentrations increased from 0.2 to 1.2 wt % with increasing proximity to the nail. Ultrahigh resolution mass spectrometry showed enrichment of nitrogen-containing compounds within the lignin and condensed aromatic domains. X-ray spectroscopic …
Land Use Influences Dissolved Organic Matter Composition In The U.S. Coastal Critical Zone Network, Aleksandar I. Goranov, Elizabeth V. Whitney, Brian R. Moyer, Katherine L. Tully, Patrick G. Hatcher, Yu-Ping Chhin
Land Use Influences Dissolved Organic Matter Composition In The U.S. Coastal Critical Zone Network, Aleksandar I. Goranov, Elizabeth V. Whitney, Brian R. Moyer, Katherine L. Tully, Patrick G. Hatcher, Yu-Ping Chhin
Chemistry & Biochemistry Faculty Publications
Coastal watersheds are highly productive biogeochemical systems supporting robust coastal fisheries and contributing significantly to the marine gross primary production flux. These ecosystems are comprised of civil infrastructure, farms, forests, and marshes, and their diversity is reflected in the quantity and quality of dissolved organic matter (DOM). Here, we assess the role of farming in influencing DOM from surface waters of six coastal tidal creeks adjacent to forest and farm sites in the US Critical Zone Network. Molecular fingerprinting using electrospray ionization - Fourier transform - ion cyclotron resonance - mass spectrometry revealed that farm-influenced DOM was enriched in nitrogen-, …
Multidentate Surfactant-Dependent Synthesis Of Giant Iridium Superstructures, Ramjee Balasubramanian, Maeren E. Hill
Multidentate Surfactant-Dependent Synthesis Of Giant Iridium Superstructures, Ramjee Balasubramanian, Maeren E. Hill
Chemistry & Biochemistry Faculty Publications
Giant superstructures of iridium, comprised of smaller spherical and slightly larger anisotropic nanoparticles, were synthesized by reducing iridium chloride in the presence of resorcinarene, a class of tetrameric macrocyclic polyphenols, with sodium borohydride in ethanol in 30 min under mild conditions. These superstructures were characterized by a range of techniques including TEM, HRTEM, EDS and other spectroscopic methods. The impact of the macrocyclic surfactant, its features and reaction conditions in dictating the formation of giant iridium superstructures was evaluated. The packing density of nanoparticles in these giant iridium superstructures could be altered qualitatively by varying the duration of the reaction, …
Feasibility Of Upcycling Spent Lithium-Ion Battery To Carbon Dioxide Capture Adsorbent, Chimezie Frank Onwudinjo
Feasibility Of Upcycling Spent Lithium-Ion Battery To Carbon Dioxide Capture Adsorbent, Chimezie Frank Onwudinjo
Master’s Theses
This study investigates the feasibility of repurposing spent lithium-ion battery (SLIB) to lithium orthosilicate (Li4SiO4), a high temperature carbon dioxide sorbent. Two synthesis pathways including conventional acid-leaching method (Scenario 1) and a pyrolysis-based route (Scenario 2) were explored. Additionally, techno-economic analysis (TEA) and lifecycle assessment (LCA) of the two processes were also performed. Different analytical characterization techniques were performed to understand the material properties of Li4SiO4 including surface area, crystallinity, morphology and thermal stability. CO2 capture performance of the synthesized Li4SiO4 was tested in a thermogravimetric analyzer (TGA) using …
Comprehensive Analytical Investigation Of Tetrahydro-4h-Chromene And Dihydropyridine Derivatives, Ryan J. Burk
Comprehensive Analytical Investigation Of Tetrahydro-4h-Chromene And Dihydropyridine Derivatives, Ryan J. Burk
Chemistry & Biochemistry Dissertations
Novel calcium channel blockers (CCBs) with dihydropyridine (DHP) or tetrahydro-4H-chromene moieties are often chiral, so effective enantiomer separation methods are needed for continued drug development. The purpose of this dissertation is to outline a comprehensive method development model for the chiral separations of DHPs and tetrahydro-4H-chromene derivatives. The scope of this dissertation is to address analytical challenges during initial synthesis, chiral separations, and data analysis during post-processing for this class of chiral compounds. The first section focuses on the method development strategies for separations of DHPs in the sub/supercritical fluid (SFC) and normal phase modes with the 2-hydroxypropyl-β-cyclodextrin stationary phase. …
Novel Methods For Environmental Fluoride Measurement, Cable Warren
Novel Methods For Environmental Fluoride Measurement, Cable Warren
Chemistry & Biochemistry Dissertations
Fluoride analysis has been an important focus of analytical analysis for many years and will continue to be so going forward. Today, fluorinated compounds, specifically per/polyfluoroalkyl substances (PFAS), better known as “forever chemicals” have captured the moment and are the subject of vast research and regulation. Under this context, I have researched new methods of fluoride separation and concentration in complex media as well as a novel method of PFAS destruction and total organic fluorine analysis for screening of PFAS in aqueous samples. Through research and work on micro-scale detection methods, an understanding of the state of the art and …
The Forensic Implications Of Hydrochloric Acid (Hcl) Exposure On Dna Preservation In Human Teeth, Shaelyn Lee Zimmerman
The Forensic Implications Of Hydrochloric Acid (Hcl) Exposure On Dna Preservation In Human Teeth, Shaelyn Lee Zimmerman
Graduate Student Theses, Dissertations, & Professional Papers
Identity is a human right, and forensic anthropological methods are often aimed at returning identity to decedents. Three main pathways are used for the identification of human remains: fingerprints, dental records, and DNA analysis. Identification efforts may be hindered when perpetrators attempt to obscure the victim’s identity. In cases where corrosive substances, such as hydrochloric acid (HCl) are used, dental comparison and fingerprinting often fail and genetic analysis becomes the best chance of achieving personal identification.
Previous studies have shown teeth are an excellent source of DNA. Large, multi-rooted teeth, such as molars, are often preferred because they contain the …
Pullulan Production From Lignocellulosic Plant Biomass Or Starch-Containing Processing Coproduct Hydrolysates, Thomas P. West
Pullulan Production From Lignocellulosic Plant Biomass Or Starch-Containing Processing Coproduct Hydrolysates, Thomas P. West
Faculty Publications
The complex polysaccharide pullulan is characterized as a glucose-containing biopolymer that is both water-soluble and neutral in polarity. A variety of commercial applications exist for pullulan, including its utilization as a flocculant, a blood plasma substitute, a food additive, a dielectric material, an adhesive, or a packaging film. The fungus Aureobasidium pullulans has used several hydrolysates derived from plant biomass or starch-containing processing coproducts to support polysaccharide production. These include various plant biomass or processing coproduct streams such as lignocellulosic-containing peat, prairie grass, stalks, hulls, straw, shells, and pods or starch-containing coproducts from the processing of corn, rice, jackfruit seeds, …