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Articles 1051 - 1080 of 1341
Full-Text Articles in Chemistry
Quantum Interference Enhancement Of The Spin-Dependent Thermoelectric Response, Runa X. Bennett, Joshua R. Hendrickson, Justin P. Bergfield
Quantum Interference Enhancement Of The Spin-Dependent Thermoelectric Response, Runa X. Bennett, Joshua R. Hendrickson, Justin P. Bergfield
Faculty publications – Physics
We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (Ss), figure-of-merit (ZsT), and maximum thermodynamic efficiency (ηsmax) caused by destructive QI. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a range of junction parameters with Ss, ZsT, and reaching peak values of 2𝜋/ √3(𝑘/𝑒)2𝜋/3(𝑘/𝑒), 1.51, and 28% of Carnot efficiency, respectively. We also find that the …
Sequential Infiltration Synthesis Of Silicon Dioxide In Polymers With Ester Groups─Insight From In Situ Infrared Spectroscopy, Mahua Biswas, Vepa Rozyyev, Anil U. Mane, Amelia Korveziroska, Uttam Manna, Jeffrey W. Elam
Sequential Infiltration Synthesis Of Silicon Dioxide In Polymers With Ester Groups─Insight From In Situ Infrared Spectroscopy, Mahua Biswas, Vepa Rozyyev, Anil U. Mane, Amelia Korveziroska, Uttam Manna, Jeffrey W. Elam
Faculty publications – Physics
New strategies to synthesize nanometer-scale silicon dioxide (SiO2) patterns have drawn much attention in applications such as microelectronic and optoelectronic devices, membranes, and sensors, as we are approaching device dimensions shrinking below 10 nm. In this regard, sequential infiltration synthesis (SIS), a two-step gas-phase molecular assembly process that enables localized inorganic material growth in the targeted reactive domains of polymers, is an attractive process. In this work, we performed in situ Fourier transform infrared spectroscopy (FTIR) measurements during SiO2 SIS to investigate the reaction mechanism of trimethylaluminum (TMA) and tri(tert-pentoxy) silanol (TPS) precursors with polymers having ester functional groups (poly(methyl …
Validating Machine And Human Decision-Making In Forensic Fire Debris Analysis, Frances A. Whitehead
Validating Machine And Human Decision-Making In Forensic Fire Debris Analysis, Frances A. Whitehead
Graduate Thesis and Dissertation 2023-2024
This work presents a background on the chemical complexity of fire debris analysis, including an ever-present matrix of pyrolysis products as the catalyst that led to the creation of the National Center for Forensic Science's Fire Debris Database. A selection of these 1,000+ casework-relevant ground truth samples was used to create two newly proposed analyst workflows to connect the current method of categorical reporting with evaluative reporting practices reflective of the strength of the evidence. Both workflows use linear sequential unmasking to help mitigate bias, a discrete scoring system for quantification of the analysis, and receiver operating characteristic (ROC) curves …
Thermosensitive Phosphors As Optical Temperature Sensors In Extreme Environments, Marcos Ramon Imer Rocha Pita
Thermosensitive Phosphors As Optical Temperature Sensors In Extreme Environments, Marcos Ramon Imer Rocha Pita
Wayne State University Dissertations
Luminescent temperature sensors offer unique advantages over thermocouples and pyrometers for applications in extreme environments such as operando wall temperature mapping of combustion engines. A refractory oxide host doped with an optically active ion has the potential to afford a thermosensitive phosphor with a well-defined temperature response in such extreme environments. However, the design of thermosensitive phosphors with targeted temperature sensitivity and spatial resolution in the operational temperature range of interest has been hindered by the inability to rationally select host–activator pairs. A major scientific question is what crystal-chemistry features a low thermal conductivity oxide must possess to afford a …
Density Functional Studies Of Molecular Separation And Charge Transport, Timothy Quainoo
Density Functional Studies Of Molecular Separation And Charge Transport, Timothy Quainoo
Wayne State University Dissertations
This thesis presents a series of studies which can be grouped majorly into two sections both focusing on the utilization of density functional theory techniques; Molecular electronics and Molecular separation. Molecular electronics has been anticipated to hold a great future as it seeks to apply molecular building blocks in the creation of electronic components. On the other hand, the utilization of mild conditions in chemical processes is geared toward the major goals of green chemistry as it produces less waste and is cost-effective. Thus, this dissertation tackles and answers some of the unanswered questions in literature by using theoretical methods …
Design And Synthesis Of Aminoglycoside-Based Heparan Sulfate Mimetics For Structure-Activity Relationship Studies Of Heparan-Binding Proteins, Joseph Wakpal
Wayne State University Dissertations
Cancer remains a formidable challenge in modern medicine, demanding innovative approaches and treatments. Among the emerging strategies, inhibiting heparanase and fibroblast growth factor 2 (FGF2) has garnered considerable attention in recent years. This dissertation presents a novel approach to designing and synthesizing a diverse library of heparan sulfate (HS) mimetics derived from aminoglycosides to study their binding to two heparin-binding proteins involved in cancer development and metastasis. Heparanase cleaves HS polysaccharide chains in the extracellular matrix (ECM) and is a regulator of aggressive tumor behavior. Clinical studies have illustrated that aberrant heparanase expression correlates with increased tumor size, amplified tumor …
Sustainable Additive Manufacturing Of Polysulfone Membranes For Liquid Separations, Brian Leonard, Harrison Loh, David Lu, Ebuka A. Ogbuoji, Isabel Escobar, Konstantinos Sierros, Oishi Sanyal
Sustainable Additive Manufacturing Of Polysulfone Membranes For Liquid Separations, Brian Leonard, Harrison Loh, David Lu, Ebuka A. Ogbuoji, Isabel Escobar, Konstantinos Sierros, Oishi Sanyal
UK CARES Faculty Publications
Membranes serve as important components for modern manufacturing and purification processes but are conventionally associated with excessive solvent usage. Here, for the first time, a procedure for fabricating large area polysulfone membranes is demonstrated via the combination of direct ink writing (DIW) with non-solvent induced phase inversion (NIPS). The superior control and precision of this process allows for complete utilization of the polymer dope solution during membrane fabrication, thus enabling a significant reduction in material usage. Compared to doctor blade fabrication, a 63% reduction in dope solution volume was achieved using the DIW technique for fabricating similarly sized membranes. Cross …
Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko
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 …
Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski
Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski
Chemistry & Biochemistry Theses - Archive
Dolerophanite Cu2OSO4 is a rare mineral found almost exclusively in the fumaroles of volcano systems and is sensitive to temperature and humidity conditions. It has a monoclinic C2/m crystal structure characterized by two-dimensional layers composed of sulfate anions dispersed amongst copper (II) oxide backbones. There has been recent interest in dolerophanite due to the magnetic properties of its Kagome-like lattice as well as its potential use as a photocatalyst or Li-ion battery electrode. Literature on the material however has been limited by the available synthesis strategies. As such, this thesis work presents a novel strategy …
Calcium Carbonate-Based Stimuli-Responsive Microcarriers For Targeted Drug Delivery Against Oral Bacterial Infections And Development Of Glass-Free Microfluidics As An Analytical Platform, Krishantha Wijewardhane
Calcium Carbonate-Based Stimuli-Responsive Microcarriers For Targeted Drug Delivery Against Oral Bacterial Infections And Development Of Glass-Free Microfluidics As An Analytical Platform, Krishantha Wijewardhane
Dissertations and Theses
Dental diseases present a significant global health challenge, affecting individuals across all age groups. This spectrum of oral health issues encompasses conditions like dental caries, periodontitis (gum disease), and oral infections. In the customer discovery interviews, dental patients have raised concerns about potential drug overexposure during and after procedures, driven by fears of adverse effects, allergies, and the increasing use of antibiotics and anesthesia. Dentists are increasingly focused on minimizing opioid and steroid-based medication doses due to potential side effects and addiction risks. This study explores an innovative approach to targeted drug delivery in the dental environment using eco-friendly and …
Structural Modification Of 4'-Aminochalcones As Α-Glucosidase Inhibitors, Emmanuel Sunday Idoko
Structural Modification Of 4'-Aminochalcones As Α-Glucosidase Inhibitors, Emmanuel Sunday Idoko
Chulalongkorn University Theses and Dissertations (Chula ETD)
Diabetes mellitus, one of the most predominant health problems worldwide, characterized by hyperglycemia, has attracted the attention of medicinal chemists. Although several therapeutic drugs have been developed and used clinically, diabetes continues to pose a growing threat to public health. One of the promising approaches for treating type 2 diabetes involves reducing the rate of carbohydrate hydrolysis by inhibiting the action of α-glucosidase. Over the years, chalcone analogues have been reported for their vast biological properties and as a promising antidiabetic agent. In this research, two series of 4'-aminochalcone derivatives were designed and synthesized as α-glucosidase inhibitors. Twenty-five alkylated 4'-aminochalcone …
High Purity Silver Nano- And Micro Particles With Controllable Shapes By Polymeric Stabilizers, Natsuda Muankhajorn
High Purity Silver Nano- And Micro Particles With Controllable Shapes By Polymeric Stabilizers, Natsuda Muankhajorn
Chulalongkorn University Theses and Dissertations (Chula ETD)
This work presents a rapid, sustainable, and efficient technique for both recovering silver microstructures from spent button batteries and fabricating flexible conductive materials. In the first phase, a green recovery method was developed using H2O2 as a reducing agent to convert silver sources into high-purity silver microstructures. The morphology of the recovered silver was controlled using polymeric stabilizers (PVP and PVA) whose molecular weights significantly influenced particle shape and aggregation. PVP promoted the formation of uniform silver microplates, while PVA yielded isotropic microspheres. The silver microstructures from the spent button batteries were converted into highly pure silver microstructures (>98%), …
A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam
A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam
Chemistry Faculty Publications
The cytotoxic and immunogenic-activating properties of a cobalt(III)-cyclam complex bearing the non-steroidal anti-inflammatory drug, flufenamic acid is reported within the context of anti-cancer stem cell (CSC) drug discovery. The cobalt(III)-cyclam complex 1 displays sub-micromolar potency towards breast CSCs grown in monolayers, 24-fold and 31-fold greater than salinomycin (an established anti-breast CSC agent) and cisplatin (an anticancer metallopharmaceutical), respectively. Strikingly, the cobalt(III)-cyclam complex 1 is 69-fold and 50-fold more potent than salinomycin and cisplatin towards three-dimensionally cultured breast CSC mammospheres. Mechanistic studies reveal that 1 induces DNA damage, inhibits cyclooxygenase-2 expression, and prompts caspase-dependent apoptosis. Breast CSCs treated with 1 exhibit …
Unusual Eluents, Small Systems, And Digital Signal Processing For Highly Efficient Greener Separations, Troy T. Handlovic
Unusual Eluents, Small Systems, And Digital Signal Processing For Highly Efficient Greener Separations, Troy T. Handlovic
Chemistry & Biochemistry Dissertations - Archive
Separation science is a rapidly evolving field, where routine analyses are now done at speeds and efficiencies not thought to be possible several years ago. The tangential field of green analytical chemistry is evolving at an even faster rate and can be considered to be in its infancy stage. As green analytical chemistry is better understood, the greenness of a method will be considered during standard method development just as resolution, sensitivity, and efficiency are considered now. The first portion of this dissertation focuses on the development of mathematical and pragmatic methods to minimize the analytical method greenness score, and …
Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss
Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss
Chemistry & Biochemistry Dissertations - Archive
Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is a method used to increase solid-phase microextraction sampling of semi-volatile organic compounds. Three studies were conducted using Vac-HS-SPME via gas chromatography - mass spectrometry (GC-MS) methods for analysis of various sample types. First, a study was performed using Vac- HS-SPME combined with a high-capacity (HC) SPME Arrow to determine the operational fundamentals and workflow necessary to achieve optimal extraction of semi-volatile compounds from a model solid matrix (Ottawa sand). The fundamentals investigated included the seals necessary to create a leak-free sampling vial under vacuum conditions; the magnitude of the vacuum exerted, and the time …
Advanced Detection Of Sars-Cov-2 And Omicron Variants Via Mxene-Graphene Hybrid Biosensors Utilizing Nucleic Acid Probes, Jiaoli Li, Yuwei Zhang, Congjie Wei, Yanxiao Li, Zhekun Peng, Hsin Yin Chuang, Logan Pearce, Adrianus Boon, Yue-Wern Huang, Dong Hyun Kim, Risheng Wang, Chenglin Wu
Advanced Detection Of Sars-Cov-2 And Omicron Variants Via Mxene-Graphene Hybrid Biosensors Utilizing Nucleic Acid Probes, Jiaoli Li, Yuwei Zhang, Congjie Wei, Yanxiao Li, Zhekun Peng, Hsin Yin Chuang, Logan Pearce, Adrianus Boon, Yue-Wern Huang, Dong Hyun Kim, Risheng Wang, Chenglin Wu
Biological Sciences Faculty Research & Creative Works
Low-cost biosensors that can rapidly and widely detect viruses are critical for faster diagnosis and treatment decision-making, especially for infections. The commonly used field-effect transistor is sensitive to the biomarker's detection but struggles with precise detection, particularly of nontargets such as ions and proteins. To overcome this limitation, we developed a field-effect transistor biosensor design based on MXene-graphene materials to increase the accuracy and sensitivity of virus detection. Based on the hybridization process between two complementary DNA strands, single-stranded nucleic acids were immobilized on the sensing surface via 3-aminopropyltriethoxysilane and glutaraldehyde to capture the nucleic acids of the target virus. …
Antibody-Driven Assembly Of Plasmonic Core–Satellites To Increase The Sensitivity Of A Sers Vertical Flow Immunoassay, Eunice Ebbah, Anthony Amissah, Jun-Hyun Kim, Jeremy D. Driskell
Antibody-Driven Assembly Of Plasmonic Core–Satellites To Increase The Sensitivity Of A Sers Vertical Flow Immunoassay, Eunice Ebbah, Anthony Amissah, Jun-Hyun Kim, Jeremy D. Driskell
Faculty Publications – Chemistry
Here, we describe a SERS-based vertical flow assay as a platform technology suitable for point-of-care (POC) diagnostic testing. A capture substrate is constructed from filter paper embedded with spherical gold nanoparticles (AuNPs) and functionalized with an appropriate capture antibody. The capture substrate is loaded into a filtration device and connected to a syringe to rapidly and repeatedly pass the sample through the sensor for efficient antigen binding. The antigen is then labeled with a SERS-active detection probe. We show that only a few Raman reporter molecules, exclusively located adjacent to the plasmonic capture substrate, generate detectible signals. To maximize the …
Weak Effects Of Prebiotically Plausible Peptides On Self-Triphosphorylation Ribozyme Function, Joshua T. Arriola, Shayan Poordian, Estefanía Martínez Valdivia, Tommy Le, Luke J. Leman, Joan G. Schellinger, Ulrich F. Müller
Weak Effects Of Prebiotically Plausible Peptides On Self-Triphosphorylation Ribozyme Function, Joshua T. Arriola, Shayan Poordian, Estefanía Martínez Valdivia, Tommy Le, Luke J. Leman, Joan G. Schellinger, Ulrich F. Müller
Chemistry and Biochemistry: Faculty Scholarship
Catalytic RNAs (ribozymes) were central to early stages of life on earth. The first ribozymes probably emerged in the presence of prebiotically generated peptides because amino acids can be generated under abiotic conditions, and amino acids can oligomerize into peptides under prebiotically plausible conditions. Here we tested whether the presence of prebiotically plausible peptides could have aided the emergence of ribozymes, by an in vitro selection of self-triphosphorylation ribozymes from random sequence in the presence of ten different octapeptides. These peptides were composed of ten different, prebiotically plausible amino acids, each as mixture of D- and L-stereoisomers. After five rounds …
Problems In Chemical Graph Theory Related To The Merrifield-Simmons And Hosoya Topological Indices, William B. O'Reilly
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 …
Phenanthrene Jamboree, Alexander D. Roth
Phenanthrene Jamboree, Alexander D. Roth
Honors Theses
Using cyclopropanated and cyclobutanated phenanthrene precursors, our hero embarks on a mission to find as many reactive intermediates as possible. Fraught with danger, romance, and mangosteens, Anderson calls this work 'monstrous' and 'alarming.'
Intercalibration: A Cornerstone Of The Success Of The Geotraces Program, Ana Aguilar-Islas, Hélène Planquette, Maeve C. Lohan, Walter Geibert, Gregory Cutter
Intercalibration: A Cornerstone Of The Success Of The Geotraces Program, Ana Aguilar-Islas, Hélène Planquette, Maeve C. Lohan, Walter Geibert, Gregory Cutter
OES Faculty Publications
The international GEOTRACES program was developed to enhance knowledge about the distribution of trace elements and their isotopes (TEIs) in the ocean and to reduce the uncertainty about their sources, sinks, and internal cycling. Recognizing the importance of intercalibration from the outset, GEOTRACES implemented intercalibration efforts early in the program, and consensus materials were generated that included the full range of TEIs dissolved in seawater, in suspended particles, and from aerosols. The GEOTRACES section cruises include “crossover station(s)” that are occupied by two or more sections and whereby all aspects of sample collection, preservation, and processing can be compared and …
Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan
Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan
OES Faculty Publications
In this Research Topic, we bring together ten articles from the diverse research communities interested in the marine iodine cycle, including paleoceanographers, atmospheric chemists, and biogeochemists. The physical chemistry underpinning iodine’s chemical speciation and transformations in the ocean is reviewed by Luther; this paper provides a theoretical basis for the field observations presented in this Research Topic.
Marine Emissions Of Methanethiol Increase Aerosol Cooling In The Southern Ocean, Charel Wohl, Julián Villamayor, Martí Galí, Anoop S. Mahajan, Rafael P. Fernández, Carlos A. Cuevas, Adriana Bossolasco, Qinyi Li, Anthony J. Kettle, Tara Williams, Roland Sarda-Esteve, Valérie Gros, Rafel Simó, Alfonso Saiz-Lopez
Marine Emissions Of Methanethiol Increase Aerosol Cooling In The Southern Ocean, Charel Wohl, Julián Villamayor, Martí Galí, Anoop S. Mahajan, Rafael P. Fernández, Carlos A. Cuevas, Adriana Bossolasco, Qinyi Li, Anthony J. Kettle, Tara Williams, Roland Sarda-Esteve, Valérie Gros, Rafel Simó, Alfonso Saiz-Lopez
OES Faculty Publications
Ocean-emitted dimethyl sulfide (DMS) is a major source of climate-cooling aerosols. However, most of the marine biogenic sulfur cycling is not routed to DMS but to methanethiol (MeSH), another volatile whose reactivity has hitherto hampered measurements. Therefore, the global emissions and climate impact of MeSH remain unexplored. We compiled a database of seawater MeSH concentrations, identified their statistical predictors, and produced monthly fields of global marine MeSH emissions adding to DMS emissions. Implemented into a global chemistry-climate model, MeSH emissions increase the sulfate aerosol burden by 30 to 70% over the Southern Ocean and enhance the aerosol cooling effect while …
Reiq-Mediated Alarmone Signalling Regulates Growth, Stress-Induced Biofilm Formation And Spore Accumulation In Clostridioides Difficile, Areej Malik, Adenrele Oludiran, Asia Poudel, Orlando Berumen Alvarez, Charles Woodward, Erin B. Purcell
Reiq-Mediated Alarmone Signalling Regulates Growth, Stress-Induced Biofilm Formation And Spore Accumulation In Clostridioides Difficile, Areej Malik, Adenrele Oludiran, Asia Poudel, Orlando Berumen Alvarez, Charles Woodward, Erin B. Purcell
Chemistry & Biochemistry Faculty Publications
The bacterial stringent response (SR) is a conserved transcriptional reprogramming pathway mediated by the nucleotide signalling alarmones, (pp)pGpp. The SR has been implicated in antibiotic survival in Clostridioides difficile, a biofilm- and spore-forming pathogen that causes resilient, highly recurrent C. difficile infections. The role of the SR in other processes and the effectors by which it regulates C. difficile physiology are unknown. C. difficile RelQ is a clostridial alarmone synthetase. Deletion of relQ dysregulates C. difficile growth in unstressed conditions, affects susceptibility to antibiotic and oxidative stressors and drastically reduces biofilm formation. While wild-type C. difficile displays increased biofilm …
Multiple Variables Influence The Finely Calibrated Antioxidant Defenses Of Clostridioides Difficile, Erin B. Purcell
Multiple Variables Influence The Finely Calibrated Antioxidant Defenses Of Clostridioides Difficile, Erin B. Purcell
Chemistry & Biochemistry Faculty Publications
The obligate anaerobe Clostridioides difficile encodes multiple reductases to detoxify molecular oxygen and reactive oxygen species. Caulat and colleagues have characterized the activity and regulation of four such reductases (L. C. Caulat, A. Lotoux, M. C. Martins, N. Kint, et al., mBio 15:e01591-24, 2024, https://doi.org/10.1128/mbio.01591-24). Each proved critical for clostridial survival in a different range of oxygen concentrations; together, they ameliorate a broad range of oxidative stress levels. Moreover, two previously uncharacterized regulators were found to control reductase gene expression in response to oxidative stress. The genetic repressor Rex and the reductase FdpF are both sensitive to the NAP …
The A²Π-X²Σ⁺ Band System Of Sco For M-Type Star Spectral Analysis, Léo Lavy, Adam Pastorek, Peter F. Bernath
The A²Π-X²Σ⁺ Band System Of Sco For M-Type Star Spectral Analysis, Léo Lavy, Adam Pastorek, Peter F. Bernath
Chemistry & Biochemistry Faculty Publications
M-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A²Π–X²Σ+ band system and can be used to measure the abundance of ScO. In this work, a new Doppler-limited resolution spectrum of ScO obtained in a hollow-cathode experiment is presented. The A²Π–X²Σ+ electronic transition is analyzed with special care dedicated to fitting the A′²Δ(v+2) ∼ A²Π(v) perturbation. Spectroscopic constants of the A²Π(v) states are reported for v ≤ 9, and a partial fit of …
Investigating The Ultrafast Dissociation Dynamics Of Energetic Materials Using Femtosecond Time-Resolved Mass Spectrometry, Jacob M. Shusterman
Investigating The Ultrafast Dissociation Dynamics Of Energetic Materials Using Femtosecond Time-Resolved Mass Spectrometry, Jacob M. Shusterman
Theses and Dissertations
Shock initiation of energetic materials produces cations and anions that can contribute to initial endothermic chemical reactions which lead to detonation. Hence, knowledge of the initial dissociation pathways of ionized energetic molecules is important for advancing the understanding of initiation mechanisms and meeting longstanding goals of the Department of Defense. Despite their potential importance, these transient charged species are difficult to detect in detonation experiments and are often ignored in molecular dynamics modeling of shocked energetic materials. However, the technique of pump-probe femtosecond time-resolved mass spectrometry (FTRMS) paired with complementary theoretical calculations can be used to elucidate initial unimolecular dissociation …
Elucidation Of The Optical Properties Of Si And Si-Ge Alloy Nanostructures With Visible To Near-Ir Photoluminescence, Griffin Spence
Elucidation Of The Optical Properties Of Si And Si-Ge Alloy Nanostructures With Visible To Near-Ir Photoluminescence, Griffin Spence
Theses and Dissertations
Silicon and silicon-germanium alloy nanostructures have garnered increasing attention in the past 25 years due to their favorable optical properties, visible to near-IR luminescence, and inherently low toxicity. While many synthetic routes have been discussed in the literature, the high-temperature, solid-state disproportionation of hydrogen silsesquioxane (HSQ) has become the most popular way to produce highly crystalline, size-tunable Si and Si-based nanostructures (NCs). It has been shown in this work that maximum annealing temperature from 450°-1100°C and the addition of GeI2or SnCl4 precursors can be used to achieve different morphologies, alloying efficiency, and sizes. Directly annealing HSQ from …
A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam
A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam
Chemistry Faculty Publications
The cytotoxic and immunogenic-activating properties of a cobalt(III)-cyclam complex bearing the non-steroidal anti-inflammatory drug, flufenamic acid is reported within the context of anti-cancer stem cell (CSC) drug discovery. The cobalt(III)-cyclam complex 1 displays sub-micromolar potency towards breast CSCs grown in monolayers, 24-fold and 31-fold greater than salinomycin (an established anti-breast CSC agent) and cisplatin (an anticancer metallopharmaceutical), respectively. Strikingly, the cobalt(III)-cyclam complex 1 is 69-fold and 50-fold more potent than salinomycin and cisplatin towards three-dimensionally cultured breast CSC mammospheres. Mechanistic studies reveal that 1 induces DNA damage, inhibits cyclooxygenase-2 expression, and prompts caspase-dependent apoptosis. Breast CSCs treated with 1 exhibit …
Multiple Imputation For Robust Cluster Analysis To Address Missingness In Medical Data, Arnold Harder, Gayla R. Olbricht, Godwin Ekuma, Daniel B. Hier, Tayo Obafemi-Ajayi
Multiple Imputation For Robust Cluster Analysis To Address Missingness In Medical Data, Arnold Harder, Gayla R. Olbricht, Godwin Ekuma, Daniel B. Hier, Tayo Obafemi-Ajayi
Mathematics and Statistics Faculty Research & Creative Works
Cluster Analysis Has Been Applied To A Wide Range Of Problems As An Exploratory Tool To Enhance Knowledge Discovery. Clustering Aids Disease Subtyping, I.e. Identifying Homogeneous Patient Subgroups, In Medical Data. Missing Data Is A Common Problem In Medical Research And Could Bias Clustering Results If Not Properly Handled. Yet, Multiple Imputation Has Been Under-Utilized To Address Missingness, When Clustering Medical Data. Its Limited Integration In Clustering Of Medical Data, Despite The Known Advantages And Benefits Of Multiple Imputation, Could Be Attributed To Many Factors. This Includes Methodological Complexity, Difficulties In Pooling Results To Obtain A Consensus Clustering, Uncertainty Regarding …