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Full-Text Articles in Chemistry

Investigating The Impact Of Secondary Activation Time On The Adsorption Properties Of Activated Biochar For Arsenic Removal From Wastewater, Achyuth Bharadwaj Rayarao May 2024

Investigating The Impact Of Secondary Activation Time On The Adsorption Properties Of Activated Biochar For Arsenic Removal From Wastewater, Achyuth Bharadwaj Rayarao

Graduate Theses and Dissertations (2019 - present)

Biochar, a naturally occurring and renewable carbon material, becomes porous through activation. Activated biochar is an ideal candidate for use as an adsorbent. The objective of this study is to investigate whether activated biochar derived from Colorado soft pine serves as a better adsorbent and demonstrates enhanced adsorption capabilities after undergoing secondary physical activation at various activation times. The effect of secondary action time on physical adsorption properties drawn from the analysis of isotherm plots, surface areas and pore size patterns were examined by using a physisorption analyzer. Chemical structures were identified using both ultimate and proximate analyses, while porosity …


Enabling More Efficient Solar Thermal Energy Production And Storage, Allan Wilson May 2024

Enabling More Efficient Solar Thermal Energy Production And Storage, Allan Wilson

Poster Presentations

Concentrated Solar Power (CSP) stores & transfers energy using a Thermal Energy Storage Fluid (EIA AEO 2022)


Development Of An Enhanced Sampling Workflow To Accelerate Molecular Docking With Sparse Biophysical Information, Zachary Stichter May 2024

Development Of An Enhanced Sampling Workflow To Accelerate Molecular Docking With Sparse Biophysical Information, Zachary Stichter

Masters Theses & Specialist Projects

Rapid docking of flexible biological macromolecules remains a significant open challenge in protein structure determination. While rigid docking is relatively simple with toolkits such as TagDock, a key obstacle to rapid flexible docking is the complexity and roughness of the free energy surface associated with protein conformational motion (often termed the many-minima problem), meaning conventional molecular dynamics methods do not effectively sample protein conformations near the interaction complex in accessible timescales. Methods such as metadynamics and replica exchange molecular dynamics exist to ameliorate this obstacle, yet these methods use nonphysical biases or random swaps to enhance sampling. In contrast, high …


The Purification And Thermal Stability Of The Peroxidase Enzyme In Cucurbita Moschata, Garen Hamner Apr 2024

The Purification And Thermal Stability Of The Peroxidase Enzyme In Cucurbita Moschata, Garen Hamner

Senior Honors Theses

Peroxidases are enzymes that catalyze the reduction of hydrogen peroxide to water while oxidizing organic substrates and are valuable in spheres like industrial and medical applications and histochemistry. Limitations still exist in the use of the well-studied horseradish peroxidase for certain activities due to limitations like poor thermal stability, thus the search for novel peroxidases that can overcome these limitations is an active area of research. Butternut squash peroxidase (Cucurbita moschata) (BSP) shows promise due to significant activity being found in the skin and apparent enhanced thermal stability, but an efficient purification scheme for it is lacking, as well as …


A Single Hydrogen Bond That Tunes Flavin Redox Reactivity And Activates It For Modification, Debarati Das, Anne-Frances Miller Apr 2024

A Single Hydrogen Bond That Tunes Flavin Redox Reactivity And Activates It For Modification, Debarati Das, Anne-Frances Miller

Markey Cancer Center Faculty Publications

Electron bifurcation produces high-energy products based on less energetic reagents. This feat enables biological systems to exploit abundant mediocre fuel to drive vital but demanding reactions, including nitrogen fixation and CO2 capture. Thus, there is great interest in understanding principles that can be portable to man-made devices. Bifurcating electron transfer flavoproteins (Bf ETFs) employ two flavins with contrasting reactivities to acquire pairs of electrons from a modest reductant, NADH. The bifurcating flavin then dispatches the electrons individually to a high and a low reduction midpoint potential (E°) acceptor, the latter of which captures most of the energy. Maximum efficiency …


Self-Assembly Of Core-Substituted Naphthalene Diimide Based Palladium (Ii) And Platinum (Ii) Macrocycles, Samantha Aragon, Camille Kwan, Franchesca Tinacba Apr 2024

Self-Assembly Of Core-Substituted Naphthalene Diimide Based Palladium (Ii) And Platinum (Ii) Macrocycles, Samantha Aragon, Camille Kwan, Franchesca Tinacba

Posters - 2024

Coordination-driven self-assembly is an efficient way to create 2D and 3D supramolecular coordination complexes (SCC) due to its predictable features of metal coordination. SCC’s represent a growing area of research with applications in various fields such as host-guest chemistry, catalysis, chemical transfer and separation, and stabilization of its reactive intermediate. Integrating various fluorophore/chromophore into these SCC’s results in unique properties and functions. In this project, core-substituted naphthalenediimide (NDI) based macrocycles were constructed via self-assembly with 90° platinum (II) and palladium (II) phosphane triflates.1H NMR and 31P NMR studies of the self-assembled product in various nonpolar to polar solvents showed two …


Myeloid-Derived Suppressor Cell Mitochondrial Fitness Governs Chemotherapeutic Efficacy In Hematologic Malignancies, Saeed Daneshmandi, Jee Eun Choi, Qi Yan, Cameron R. Macdonald, Manu Pandey, Mounika Goruganthu, Nathan Roberts, Prashant K. Singh, Richard M. Higashi, Andrew N. Lane, Teresa W-M Fan, Jianmin Wang, Philip L. Mccarthy, Elizabeth A. Repasky, Hemn Mohammadpour Mar 2024

Myeloid-Derived Suppressor Cell Mitochondrial Fitness Governs Chemotherapeutic Efficacy In Hematologic Malignancies, Saeed Daneshmandi, Jee Eun Choi, Qi Yan, Cameron R. Macdonald, Manu Pandey, Mounika Goruganthu, Nathan Roberts, Prashant K. Singh, Richard M. Higashi, Andrew N. Lane, Teresa W-M Fan, Jianmin Wang, Philip L. Mccarthy, Elizabeth A. Repasky, Hemn Mohammadpour

Markey Cancer Center Faculty Publications

Myeloid derived suppressor cells (MDSCs) are key regulators of immune responses and correlate with poor outcomes in hematologic malignancies. Here, we identify that MDSC mitochondrial fitness controls the efficacy of doxorubicin chemotherapy in a preclinical lymphoma model. Mechanistically, we show that triggering STAT3 signaling via β2-adrenergic receptor (β2-AR) activation leads to improved MDSC function through metabolic reprogram- ing, marked by sustained mitochondrial respiration and higher ATP generation which reduces AMPK signaling, altering energy metabolism. Furthermore, induced STAT3 signaling in MDSCs enhances glutamine consumption via the TCA cycle. Metabolized glutamine generates itaconate which downregulates mitochondrial reactive oxygen species via regulation of …


Leveraging The Hmbc To Facilitate Metabolite Identification, Fatema Bhinderwala, Thao Vu, Thomas G. Smith, Julian Kosacki, Darrell D. Marshall, Yuhang Xu, Martha D. Morton, Robert Powers Mar 2024

Leveraging The Hmbc To Facilitate Metabolite Identification, Fatema Bhinderwala, Thao Vu, Thomas G. Smith, Julian Kosacki, Darrell D. Marshall, Yuhang Xu, Martha D. Morton, Robert Powers

Department of Chemistry: Faculty Publications

The accuracy and ease of metabolite assignments from a complex mixture are expected to be facilitated by employing a multi-spectral approach. The 2D 1H-13C HSQC and 2D 1H-1H-TOCSY are the experiments commonly used for metabolite assignments. The 2D 1H-13C HSQC-TOCSY and 2D 1H-13C HMBC are routinely used by natural products chemists but have seen minimal usage in metabolomics despite the unique information, the nearly complete 1H-1H and 1H-13C and spin systems provided by these experiments that may improve the accuracy and reliability …


Β-Sheets Mediate The Conformational Change And Allosteric Signal Transmission Between The Aslov2 Termini, Sian Xiao, Mayar Terek Ibrahim, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao Mar 2024

Β-Sheets Mediate The Conformational Change And Allosteric Signal Transmission Between The Aslov2 Termini, Sian Xiao, Mayar Terek Ibrahim, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

Avena sativa phototropin 1 light-oxygen-voltage 2 domain (AsLOV2) is a model protein of Per-Arnt-Sim (PAS) superfamily, characterized by conformational changes in response to external environmental stimuli. This conformational change begins with the unfolding of the N-terminal A'α helix in the dark state followed by the unfolding of the C-terminal Jα helix. The light state is characterized by the unfolded termini and the subsequent modifications in hydrogen bond patterns. In this photoreceptor, β-sheets are identified as crucial components for mediating allosteric signal transmission between the two termini. Through combined experimental and computational investigations, the Hβ …


Tunable Magnetic Coupling In Graphene Nanoribbon Quantum Dots, Peter H. Jacobse, Mamun Sarker, Anshul Saxena, Brookhaven National Laboratory, Ziyi Wang, Emma Berger, Narayana R. Aluru, Alexander Sinitskii, Michael F. Crommie Feb 2024

Tunable Magnetic Coupling In Graphene Nanoribbon Quantum Dots, Peter H. Jacobse, Mamun Sarker, Anshul Saxena, Brookhaven National Laboratory, Ziyi Wang, Emma Berger, Narayana R. Aluru, Alexander Sinitskii, Michael F. Crommie

Department of Chemistry: Faculty Publications

Carbon-based quantum dots (QDs) enable flexible manipulation of electronic behavior at the nanoscale, but controlling their magnetic properties requires atomically precise structural control. While magnetism is observed in organic molecules and graphene nanoribbons (GNRs), GNR precursors enabling bottom-up fabrication of QDs with various spin ground states have not yet been reported. Here the development of a new GNR precursor that results in magnetic QD structures embedded in semiconducting GNRs is reported. Inserting one such molecule into the GNR backbone and graphitizing it results in a QD region hosting one unpaired electron. QDs composed of two precursor molecules exhibit nonmagnetic, antiferromagnetic, …


De Novo Drug Design Using Transformer-Based Machine Translation And Reinforcement Learning Of An Adaptive Monte Carlo Tree Search, Dony Ang, Cyril Rakovski, Hagop S. Atamian Jan 2024

De Novo Drug Design Using Transformer-Based Machine Translation And Reinforcement Learning Of An Adaptive Monte Carlo Tree Search, Dony Ang, Cyril Rakovski, Hagop S. Atamian

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The discovery of novel therapeutic compounds through de novo drug design represents a critical challenge in the field of pharmaceutical research. Traditional drug discovery approaches are often resource intensive and time consuming, leading researchers to explore innovative methods that harness the power of deep learning and reinforcement learning techniques. Here, we introduce a novel drug design approach called drugAI that leverages the Encoder–Decoder Transformer architecture in tandem with Reinforcement Learning via a Monte Carlo Tree Search (RL-MCTS) to expedite the process of drug discovery while ensuring the production of valid small molecules with drug-like characteristics and strong binding affinities towards …


Synthesis And Characterization Of Bio Based Amphiphilic Molecules, Vandana Singh Jan 2024

Synthesis And Characterization Of Bio Based Amphiphilic Molecules, Vandana Singh

Theses and Dissertations

Among various molecular self-assemblies, low molecular weight gelators (LMWGs), that can form gels in organic solvents/water/oils, have gained much research attention due to their huge potential applications. Generally, gels are soft nanomaterials formed by the self-assembly of amphiphilic molecules into a three-dimensional fibrous network entrapping the solvent.

As these gels are formed by self-assembly via non-covalent interactions they are reversible and differ from macromolecular gels. To synthesize LMWGs, biomolecules such as fats, oils, fatty acids, lignocelluloses, sugars, amino acids, and peptides are commonly used as their inherent property favors self-assembly. In the current scenario, interest in synthesizing bio-based gelators has …


Group 14 Metallocene Catalysts For Carbonyl Hydroboration And Cyanosilylation, Haley J. Robertson, Mallory N. Fujiwara, Allegra L. Liberman-Martin Jan 2024

Group 14 Metallocene Catalysts For Carbonyl Hydroboration And Cyanosilylation, Haley J. Robertson, Mallory N. Fujiwara, Allegra L. Liberman-Martin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

A series of six Group 14 metallocene compounds (M = Ge, Sn, Pb) were studied as catalysts for carbonyl hydroboration and cyanosilylation reactions at room temperature. Both bis(pentamethylcyclopentadienyl) and tetramethyldisiloxa[3]metallocenophane compounds were compared. The tin and lead metallocenophanes exhibited the highest reactivity in hydroboration and cyanosilylation reactions. Hammett analysis of aldehyde hydroboration provided a ρ value of 0.73, suggesting a buildup of negative charge during the turnover-limiting step, consistent with the transition state for hydride transfer to the carbonyl center. NMR studies of Lewis acidity indicate that the Ge, Sn, and Pb tetramethyldisiloxa[3]metallocenophane compounds are weak Lewis acids.


Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko Jan 2024

Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko

UK CARES Faculty Publications

The scalable commercialization of organic electronics wherein p-conjugated polymers serve as the semiconductors hinges on precise control of the material electronic, redox, optical, and mechanical properties, which are each highly influenced by local and long-range morphology. Here, we undertake atomistic molecular dynamics (MD) simulations at three temperatures (150 K, 300 K, and 400 K) to assess the morphological and mechanical response of bulk poly(3-hexylthiophene) (P3HT), a representative homopolymer of interest as an organic semiconductor (OS). As P3HT is a semicrystalline polymer, we characterize mechanical properties for both amorphous and crystalline P3HT models to derive insights into structure–property relationships, including Young’s …


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

College of Graduate Studies: Theses & 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 …


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

Graduate Theses/Dissertations

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 …


Α-Hydroxy C–H Functionalization Of Alcohols Via Boronic Acid, Hat, Photoredox Triad Catalytic System, Seth Christopher Cowan Jan 2024

Α-Hydroxy C–H Functionalization Of Alcohols Via Boronic Acid, Hat, Photoredox Triad Catalytic System, Seth Christopher Cowan

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation explores the research that I have conducted in my time at West Virginia University. Most of my work has focused on the development of methods and studies to further understand the α-OH C–H functionalization of alcohols. This work involves a system of catalysts including photocatalysts, HAT catalysts, and boronic acid catalysts. Chapter 1 highlights a background for each of these areas. Photoredox catalysis has been an increasing area of chemistry over the past two decades as this technique can be used to design conditions to form new bonds in a selective manner through the utilization of light energy. …


Extended Conformations Of Bifurcating Electron Transfer Flavoprotein Constitute Up To Half The Population, Possibly Mediating Conformational Change, Sharique A. Khan, Alan Hicks, Wellington C. Leite, James Byrnes, Biswajit Gorai, Maria-Andrea Mroginski, Hugh O'Neill, Anne-Francis Miller Jan 2024

Extended Conformations Of Bifurcating Electron Transfer Flavoprotein Constitute Up To Half The Population, Possibly Mediating Conformational Change, Sharique A. Khan, Alan Hicks, Wellington C. Leite, James Byrnes, Biswajit Gorai, Maria-Andrea Mroginski, Hugh O'Neill, Anne-Francis Miller

Markey Cancer Center Faculty Publications

Electron transfer bifurcation enables biological systems to drive unfavourable (endergonic) electron transfer by coupling it to favourable (exergonic) transfer of a second electron. In electron transfer flavoproteins (ETFs), a domain-scale conformational change is believed to sever the favourable pathway after a single electron has used it, thereby preventing the energy dissipation that would accompany exergonic transfer of the second electron. To understand the conformation change that participates in turnover, we have deployed small-angle neutron scattering (SANS) and computational techniques to characterize the bifurcating ETF from Acidaminococcus fermentans (AfeETF). SANS data reveal an overall radius of gyration (Rg) of 30.1 ± …


Perfluorooctanesulfonic Acid Exposure Leads To Downregulation Of 3-Hydroxy-3-Methylglutaryl-Coa Synthase 2 Expression And Upregulation Of Markers Associated With Intestinal Carcinogenesis In Mouse Intestinal Tissues, Josiane Weber Tessmann, Pan Deng, Jerika Durham, Chang Li, Moumita Banerjee, Qingding Wang, Ryan A. Goettl, Daheng He, Chi Wang, Eun Y. Lee, B. Mark Evers, Bernhard Hennig, Yekaterina Y. Zaytseva Jan 2024

Perfluorooctanesulfonic Acid Exposure Leads To Downregulation Of 3-Hydroxy-3-Methylglutaryl-Coa Synthase 2 Expression And Upregulation Of Markers Associated With Intestinal Carcinogenesis In Mouse Intestinal Tissues, Josiane Weber Tessmann, Pan Deng, Jerika Durham, Chang Li, Moumita Banerjee, Qingding Wang, Ryan A. Goettl, Daheng He, Chi Wang, Eun Y. Lee, B. Mark Evers, Bernhard Hennig, Yekaterina Y. Zaytseva

Markey Cancer Center Faculty Publications

Perfluorooctanesulfonic acid (PFOS) is a widely recognized environment pollutant known for its high bio- accumulation potential and a long elimination half-life. Several studies have shown that PFOS can alter multiple biological pathways and negatively affect human health. Considering the direct exposure to the gastrointestinal (GI) tract to environmental pollutants, PFOS can potentially disrupt intestinal homeostasis. However, there is limited knowledge about the effect of PFOS exposure on normal intestinal tissues, and its contribution to GI- associated diseases remains to be determined. In this study, we examined the effect of PFOS exposure on the gene expression profile of intestinal tissues of …


The Relationship Between Metacognition, Study Strategies, And Students’ Performances In General Chemistry And Organic Chemistry Courses, Nghiem Uy Tieu Jan 2024

The Relationship Between Metacognition, Study Strategies, And Students’ Performances In General Chemistry And Organic Chemistry Courses, Nghiem Uy Tieu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Many students find General Chemistry challenging, and studies have shown a link between students’ grades in chemistry and a decrease in interest in STEM fields. Similarly, Organic Chemistry has also been typically identified as a difficult course for many undergraduate students and has a notoriously high failure rate. Numerous studies have explored various methods to enhance students’ performance and experience in both General Chemistry and Organic Chemistry, but there hasn’t been much focus on students’ study strategies. In addition, metacognition, the skill of thinking about one’s thinking, had been proven in studies as a vital role in enhancing students’ achievements. …


Synthesis Of A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Pyridinyl Groups For Volatile Guest Molecule, Boluwatife S. Ajewole Jan 2024

Synthesis Of A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Pyridinyl Groups For Volatile Guest Molecule, Boluwatife S. Ajewole

Masters Theses

Supramolecular and Molecular chemistry offer an expanding array of applications for the development of smart devices, with calixarene-based molecular baskets playing a pivotal role in host-guest chemistry. A key concept in this field is the design of "smart" molecules with gate-like features, which can selectively transport chemical or biochemical species that are volatile, reactive, or sensitive to typical solution environments. These molecular hosts are engineered with predefined groups that respond to external stimuli, such as changes in concentration, temperature, or pH.

Molecular baskets are synthetic host molecules designed to capture guest molecules selectively through adjustable gates. In our study, we …


Fundamental Studies Of Optical Properties And Electrocatalytic Properties Of Low Dimensional Nanomaterials Carbon Nano Dots And 2d Transition Metal Dichalcogenides, Nadeesha Kothalawala Jan 2024

Fundamental Studies Of Optical Properties And Electrocatalytic Properties Of Low Dimensional Nanomaterials Carbon Nano Dots And 2d Transition Metal Dichalcogenides, Nadeesha Kothalawala

Theses and Dissertations--Chemistry

Low dimensional nanomaterials are widely used in a variety of applications such as opto-electronics, energy production and storage, and bio-medical applications due to their unique optical, catalytic, electronic, and mechanical properties. Most of the nanomaterials offer a plethora of modifications in their structure, composition, morphology, and dimensionality that can lead to the manipulation of their physiochemical properties. This dissertation presents insight into two types of compelling nanomaterials: carbon nanodots (CND) and transition metal dichalcogenides (TMD), investigating their optical and electrocatalytic properties respectively.

Carbon nanodots (CND) are a promising class of photoluminescent nanomaterials that hold a significant potential in many optoelectronic …


Use Of Interlaboratory Studies For The Development Of Consensus-Based Criteria For The Elemental Analysis Of Electrical Tapes, Lacey M. Leatherland Jan 2024

Use Of Interlaboratory Studies For The Development Of Consensus-Based Criteria For The Elemental Analysis Of Electrical Tapes, Lacey M. Leatherland

Graduate Theses, Dissertations, and Problem Reports (ETD)

Tape evidence is often used in criminal cases involving violent crimes, kidnappings, improvised explosive devices (IEDs), and drug trafficking. This evidence can reveal potential links between suspects, items, or scenes. The forensic examination of electrical tape can provide investigative leads or offer support to alternative hypotheses evaluated in the courtroom. A conventional analytical scheme includes microscopic examination, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy Energy Dispersive Spectrometry (SEM-EDS), and Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS). Elemental analysis of electrical tapes is commonly achieved using SEM-EDS; however, recent scientific literature suggests that this analysis can evolve from using SEM-EDS to …


Variables Affecting The Extraction Of Antioxidants In Cold And Hot Brew Coffee: A Review, Brian Yust, Frank Wilkinson, Niny Rao Dec 2023

Variables Affecting The Extraction Of Antioxidants In Cold And Hot Brew Coffee: A Review, Brian Yust, Frank Wilkinson, Niny Rao

College of Life Sciences Faculty Papers

Coffee beans are a readily available, abundant source of antioxidants used worldwide. With the increasing interest in and consumption of coffee beverages globally, research into the production, preparation, and chemical profile of coffee has also increased in recent years. A wide range of variables such as roasting temperature, coffee grind size, brewing temperature, and brewing duration can have a significant impact on the extractable antioxidant content of coffee products. While there is no single standard method for measuring all of the antioxidants found in coffee, multiple methods which introduce the coffee product to a target molecule or reagent can be …


Exploring Soybean Oil-Based Polyol And Effect Of Non-Halogenated Flame Retardants In Rigid Polyurethane Foam, Sahithi Kondaveeti Dec 2023

Exploring Soybean Oil-Based Polyol And Effect Of Non-Halogenated Flame Retardants In Rigid Polyurethane Foam, Sahithi Kondaveeti

Electronic Theses & Dissertations

To address the increasing demand for sustainable biomaterials due to the depletion of fossil fuel resources and growing environmental concerns, a new type of biodegradable and environmentally friendly rigid polyurethane foam (RPUF) has been synthesized. These foams are derived from chemically modified soybean oil-based polyol obtained from soybean oil by epoxidation followed by a ring-opening reaction. Polyurethane foam is generally used in construction, furniture, and automobile industries but is highly flammable and releases toxic gases and smoke during combustion. In this study, a highly efficient synergistic effect halogen-free flame-retardant (FR) melamine salt, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA) was synthesized from …


Enhanced Mechanical Strength Of Soybean Oil-Based Non-Isocyanate Polyurethane Adhesive For Wood Application By Introducing Nanofillers, Vatsal Chaudhari Dec 2023

Enhanced Mechanical Strength Of Soybean Oil-Based Non-Isocyanate Polyurethane Adhesive For Wood Application By Introducing Nanofillers, Vatsal Chaudhari

Electronic Theses & Dissertations

Polyurethane (PU) is a versatile material that finds extensive use in various industries including bedding, construction, automotive, and packaging. Historically, this particular polymer relied significantly on petrochemical resources, a practice that was considered to have negative environmental impacts. The conventional method for preparing PU involves the use of isocyanate, which is a disadvantage due to its negative impact on the environment and human health. The resolution of this problem entails identifying an appropriate substitute for petroleum-derived products that minimize their impact on both the environment and human health. The researchers earlier utilized soybean oil, for the formulation of PUs in …


Castor Oil Polyol-Based Adhesives With Additional Crosslinker For Improvement In Mechanical And Thermal Properties., Yash Desai Dec 2023

Castor Oil Polyol-Based Adhesives With Additional Crosslinker For Improvement In Mechanical And Thermal Properties., Yash Desai

Electronic Theses & Dissertations

Polyurethanes (PU) have been promising polymeric materials with many applications, including adhesives. Projecting an estimated revenue from 42.8 billion $ in 2021 to 61.5 billion $ by 2026. However, a large number of PU adhesives are sourced from petroleum products. Therefore, to lower the dependence on non-renewable resources and provide sustainable and affordable alternatives. In this work will synthesize bio-based adhesives of polyurethane from modified castor oil-based polyol. Generally, polyurethane reaction depends on the properties of polyol and isocyanates. The most important aspect of these reactions is the OH number of the polyol, which is responsible for the crosslinking and …


Mutational Analysis Of The Nitrogenase Carbon Monoxide Protective Protein Cown Reveals That A Conserved C‑Terminal Glutamic Acid Residue Is Necessary For Its Activity, Dustin L. Willard, Joshuah J. Arellano, Mitch Underdahl, Terrence M. Lee, Avinash S. Ramaswamy, Gabriella Fumes, Agatha Kliman, Emily Y. Wong, Cedric P. Owens Dec 2023

Mutational Analysis Of The Nitrogenase Carbon Monoxide Protective Protein Cown Reveals That A Conserved C‑Terminal Glutamic Acid Residue Is Necessary For Its Activity, Dustin L. Willard, Joshuah J. Arellano, Mitch Underdahl, Terrence M. Lee, Avinash S. Ramaswamy, Gabriella Fumes, Agatha Kliman, Emily Y. Wong, Cedric P. Owens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Nitrogenase is the only enzyme that catalyzes the reduction of nitrogen gas into ammonia. Nitrogenase is tightly inhibited by the environmental gas carbon monoxide (CO). Many nitrogen fixing bacteria protect nitrogenase from CO inhibition using the protective protein CowN. This work demonstrates that a conserved glutamic acid residue near the C-terminus of Gluconacetobacter diazotrophicus CowN is necessary for its function. Mutation of the glutamic acid residue abolishes both CowN’s protection against CO inhibition and the ability of CowN to bind to nitrogenase. In contrast, a conserved C-terminal cysteine residue is not important for CO protection by CowN. Overall, this work …


Differentiation Of Human, Dog, And Cat Hair Fibers Using Dart Tofms And Machine Learning, Laura Ahumada, Erin R. Mcclure-Price, Chad Kwong, Edgard O. Espinoza, John Santerre Dec 2023

Differentiation Of Human, Dog, And Cat Hair Fibers Using Dart Tofms And Machine Learning, Laura Ahumada, Erin R. Mcclure-Price, Chad Kwong, Edgard O. Espinoza, John Santerre

SMU Data Science Review

Hair is found in over 90% of crime scenes and has long been analyzed as trace evidence. However, recent reviews of traditional hair fiber analysis techniques, primarily morphological examination, have cast doubt on its reliability. To address these concerns, this study employed machine learning algorithms, specifically Linear Discriminant Analysis (LDA) and Random Forest, on Direct Analysis in Real Time time-of-flight mass spectra collected from human, cat, and dog hair samples. The objective was to develop a chemistry- and statistics-based classification method for unbiased taxonomic identification of hair. The results of the study showed that LDA and Random Forest were highly …


Development Of A Methodology For The Quantification Of Reaerosolization Of A Biological Contaminate Surrogate Particle From A Military Uniform Fabric, George Cooksey, Jeremy M. Slagley, Casey W. Cooper, Douglas Lewis, Alisha Helm Dec 2023

Development Of A Methodology For The Quantification Of Reaerosolization Of A Biological Contaminate Surrogate Particle From A Military Uniform Fabric, George Cooksey, Jeremy M. Slagley, Casey W. Cooper, Douglas Lewis, Alisha Helm

Faculty Publications

In a mass casualty medical evacuation after a bioaerosol (BA) dispersal event, a decontamination (DC) method is needed that can both decontaminate and prevent biological particle (BP) re-aerosolization (RA) of contaminated clothes. However, neither the efficacy of current DC methods nor the risk of BP RA is greatly explored in the existing literature. The goals of this study were to develop a repeatable method to quantify the RA of a biological contaminant off military uniform fabric swatches and to test the efficacy of one DC protocol (high-volume, low-pressure water) using 1 µm polystyrene latex (PSL) spheres as a surrogate. A …