Physical Sciences and Mathematics Commons^™

Effects Of Surface Ligation On Charge Extraction From Wurtzite Cadmium Selenide Quantum Platelets And Quantum Belts, Hailey Meyer

Arts & Sciences Electronic Theses and Dissertations

This dissertation presents the synthesis of flat, colloidal wurtzite CdSe quantum platelets and quantum belts for ligand exchange to novel and existing organic and inorganic L-, X-, and Z- type ligands. Use of these ligands in conjunction with the semiconductor nanocrystals allows for examination of their ligand exchange abilities, photoluminescence quenching efficiencies, and charge transfer properties.

First, zinc and cadmium dithiocarbamate compounds [M(S2CNR1R2)2] are used as ligands on wurtzite CdSe quantum belts. Complete ligand exchange is achieved when the belts are initially ligated with Cd(oleate)2, a Z-type ligand, prior to the exchange, as opposed to n-octylamine or ammonia, which are …

Development Of Redox-Responsive Phenazine-Based Foldamers. Acylative Kinetic Resolution Of Hydroxamic Acids, Jingwei Yin

Arts & Sciences Electronic Theses and Dissertations

Two different research directions have been presented in this thesis. The first project is about phenazine-based foldamers as molecular actuators. Researchers have been interested in the design and synthesis of foldamers and molecular actuators for years. We began our exploration by demonstrating that phenazine-1,6-dicarboxamides can function as redox-responsive molecular switches. We then designed and synthesized two generations of phenazine-based interleafed foldamers and studied their stability and redox behaviors under chemical and electrochemical conditions. In the second project, we have developed the first acylative kinetic resolution on hydroxamic acids. Although chiral hydroxamic acids have extensive applications, synthetic methods towards them are …

Functionalized Plasmonic Nanostructures For Ultrasensitive Single Cell Analysis, Priya Rathi

Arts & Sciences Electronic Theses and Dissertations

Ultrasensitive detection and quantification of soluble, secreted and cell surface-bound proteins is critical for advancing our understanding of cellular systems, enabling effective drug development, novel therapies, and bio-diagnostics. However, exiting technologies are largely limited by their sensitivity, making the detection and quantification of low-abundant proteins extremely challenging. This forms a major barrier in various fields of biology and biomedical sciences. In this work, we introduce novel cellular analysis methodologies based on plasmon-enhanced fluorescence for analyzing cell structure and probing surface and secreted proteins from cells. In the first part, we introduce plasmon-enhanced expansion microscopy and demonstrate the effectiveness of employing …

Toward Enhancing The Synthesis Of Renewable Polymers: Feedstock Conversions And Functionalizable Copolymers, Tedd Casey Wiessner

Arts & Sciences Electronic Theses and Dissertations

This thesis describes research under the rubric of the Center for Sustainable Polymers that is aimed at two separate goals. The goal of the first project (Chapters 1 and 2) was to develop a deeper mechanistic understanding of a method for the synthesis of linear α-olefins, while the second aimed at synthesizing statistical copolymers that incorporate olefin-containing monomers through ring-opening transesterification polymerization and showing that these copolymers could be functionalized. In Chapter 1, published methods for the conversion of fatty acids to linear α-olefins are reviewed to provide context for the mechanistic work we accomplished (Chapter 2). In Chapter 2 …

Uv-Light-Tunable P-/N-Type Chemiresistive Gas Sensors Based On Quasi-1d Tis3 Nanoribbons: Detection Of Isopropanol At Ppm Concentrations, Victor V. Sysoev, Andrey V. Lashkov, Alexey Lipatov, Ilya A. Plugin, Michael Bruns, Dirk Fuchs, Alexey S. Varezhnikov, Mustahsin Adib, Martin Sommer, Alexander Sinitskii

Chemistry Department: Faculty Publications

The growing demand of society for gas sensors for energy-efficient environmental sensing stimulates studies of new electronic materials. Here, we investigated quasi-one-dimensional titanium trisulfide (TiS₃) crystals for possible applications in chemiresistors and on-chip multisensor arrays. TiS₃ nanoribbons were placed as a mat over a multielectrode chip to form an array of chemiresistive gas sensors. These sensors were exposed to isopropanol as a model analyte, which was mixed with air at low concentrations of 1–100 ppm that are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit. The tests were performed at room temperature (RT), as …

An Imaging Mass Spectrometry Investigation Into The N-Linked Glycosylation Landscape Of Pancreatic Ductal Adenocarcinoma And The Development Of Associated Tools For Enhanced Glycan Separation And Characterization, Colin Mcdowell

MUSC Theses and Dissertations

The severity of pancreatic ductal adenocarcinoma (PDAC) is largely attributed to a failure to detect the disease before metastatic spread has occurred. CA19-9, a carbohydrate biomarker, is used clinically to surveille disease progression, but due to specificity challenges is not suitable for early discovery. As CA19-9 and other prospective markers are glycan epitopes, there is great clinical interest in understanding the glycobiology of pancreatic cancer. Unfortunately, few studies have been able to link glycosylation changes directly to pancreatic tumors and instead have focused on peripheral glycan alterations in the serum of PDAC patients. To address this gap in our understanding, …

Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen

Theses and Dissertations

The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …

The Chemistry And Catalytic Activity Of Dehydrogenative Silylation And Hydroboration Of Complexes Bearing Semirigid Ligands With Group 14 Elements, Niroshani S. Abeynayake

Theses and Dissertations

Incorporation of silicon in the ligand backbone would yield electron-rich metal complexes upon coordination to transition metal complexes. The coordination chemistry of semirigid benzyl phosphines bearing a single or multiple phosphorus atoms and varying number of Si−H moieties has gained interest in recent years. This dissertation focuses on synthesizing silyl and germyl transition metal complexes of groups 9 and 10. Chapter II presents the synthesis of a family of four coordinated 14-electron rhodium complexes. The newly synthesized complexes were characterized in solution by multinuclear NMR spectroscopy and in the solid-state by single-crystal X-ray diffraction. These d⁶ complexes possess sawhorse …

Groundwater Remediation Using Modified Biochar, Kers Ung-Watson, Ismail Abdulraheem, Nikki Tibayan, Suraj Pochampally

Undergraduate Research Symposium Posters

Biochar, a lightweight black residue made of carbon, has proved to be an effective adsorbent to remove TCE from groundwater. Not only is it an economical substitute for conventional adsorbents but it can be created by using a variety of organic materials. For this project, it will rely on walnut shell feedstock to create biochar as this had the best ability to adsorb TCE.

Development Of A Novel Ionic Liquid-Coated Adsorbent For Treating Emerging Contaminants In Recycled Water On The International Space Station, Madeline Carroll, Gabson Baguma, Savanna Vacek

Undergraduate Research Symposium Posters

Synthesize at least 3 biobased ionic liquids. Optimize method for conducting liquid-liquid extractions. Analyze and quantify how much DMSO2 is removed by the ionic liquids. Coat biochar with the most effective biobased ionic liquids.

Trapping And Cooling Of Ca+ For Cold Ion-Radical Collisions, Bernardo Gutierrez

Undergraduate Research Symposium Posters

Free radicals are molecules that contain an unpaired valence electron which induces high reactivity. Ion radical reactions are typically exothermic and have low (or zero) activation energy. It is for these reasons that ion-radical reactions are believed to dominate in interstellar clouds where temperatures hover around 3-10K. State-to-state measurements require precision control of both reactants.

The Design, Synthesis, And Investigation Into Small Molecule Modulators Of The Src Homology 2 Domain-Containing Inositol 5’-Phosphatase (Ship), Shea Thomas Meyer

Dissertations - ALL

The PI3K pathway is a major cell signaling pathway that influences survival and longevity in eukaryotic cells. Abnormal signaling of this pathway has been implicated in a number of disorders, including Alzheimer's disease and cancer. The PI3K pathway utilizes the inositolphospholipid PI(3,4,5)P3 as a key secondary messenger in the transmission of signals from outside the cell to the nucleus. The SRC Homology 2 containing Inositol 5’-Phosphatase (SHIP) also plays a key role in the PI3K pathway, mediating hydrolysis of the inositol phospholipid PI(3,4,5)P3 to PI(3,4)P2. Early testing has shown modulation of SHIP activity through the use of small molecule modulators …

Enhanced Neurologic Concept Recognition Using A Named Entity Recognition Model Based On Transformers, Sima Azizi, Daniel B. Hier, Donald C. Wunsch

Chemistry Faculty Research & Creative Works

Although Deep Learning Has Been Applied to the Recognition of Diseases and Drugs in Electronic Health Records and the Biomedical Literature, Relatively Little Study Has Been Devoted to the Utility of Deep Learning for the Recognition of Signs and Symptoms. the Recognition of Signs and Symptoms is Critical to the Success of Deep Phenotyping and Precision Medicine. We Have Developed a Named Entity Recognition Model that Uses Deep Learning to Identify Text Spans Containing Neurological Signs and Symptoms and Then Maps These Text Spans to the Clinical Concepts of a Neuro-Ontology. We Compared a Model based on Convolutional Neural Networks …

Guanidinium–Amino Acid Hydrogen-Bonding Interactions In Protein Crystal Structures: Implications For Guanidinium-Induced Protein Denaturation, Indu Negi, Raman Jangra, Amit Gharu, John F. Trant, Purshotam Sharma

Chemistry and Biochemistry Publications

In the present work, 86 available high resolution X-ray structures of proteins that contain one or more guanidinium ions (Gdm+) are analyzed for the distribution and nature of noncovalent interactions between Gdm+ and amino-acid residues. A total of 1044 hydrogen-bonding interactions were identified, of which 1039 are N–H⋯O, and five are N–H⋯N. Acidic amino acids are more likely to interact with Gdm+ (46% of interactions, 26% Asp and 20% Glu), followed by Pro (19% of interactions). DFT calculations on the identified Gdm+–amino acid hydrogen-bonded pairs reveal that although Gdm+ interacts primarily with the backbone amides of nonpolar amino acids, Gdm+ …

Computer Simulation Of The Light Absorption Band Of The Jumping Spider Isorhodopsin, Noah Zoldak

Honors Projects

In order to simulate the photoisomerization of the 9-cis Jumping Spider Isorhodopsin (JSiR-1) it is necessary to first simulate its light-absorption band. Here we report on the absorption band simulated using protein models constructed using the advanced Automatic Rhodopsin Modeling (a-ARM) program. A population of S₀ models was created and the corresponding S₀ to S₁ transitions were determined for each member of the resulting population. The calculation resulted in a Gaussian plot showing that the wavelength of the absorption maximum of 560 nm (a violet color) that is consistent, but red-shifted, with respect the experimentally observed value.

Standardization Of A Latent Blood Visualizer Based Upon Dna Degradation, Kailey M. Van 'T Hoff

Honors Projects

Latent blood visualizers have been used in forensic science since 1937 beginning with Luminol. These visualizers through different types of reactions react with trace amounts of blood that cannot be seen with the naked human eye. These different reactions produce color that can then be seen by examiners. The four types of latent blood visualizers that were compared is luminol, leuco crystal violet, fluorescein, and bluestar. Luminol and bluestar use chemiluminescence, fluorescein uses florescent, and leuco crystal violet uses oxidation to react with iron in hemoglobin. At crime scenes when blood is detected which includes with the blood visualizers the …

Hydrogen Bonding In Small Model Peptides; The Dft And Mp2 Study, Gracie Smith, Martina Kaledin

Symposium of Student Scholars

Formamide is a small model compound for the study of the peptide bond. The peptide bond links amino acids together, specifies rigidity to the protein backbone, and includes the essential docking sites for hydrogen-bond-mediated protein folding and protein aggregation, namely, the C=O acceptor and the N-H donor parts. Therefore, the infrared C=O (amide-I) and N-H (amide-A) vibrations provide sensitive and widely used probes into the structure of peptides. This computational chemistry work, we study hydrogen bonds in formamide dimer isomers. We evaluate the accuracy of the density functional theory (DFT) and many-body perturbation theory to the 2^nd order (MP2) …

Investigating The Electrochemical Behavior Of Dihydropyrrolopyroles For Use As Anodically Coloring Electrochromes, Perry Skiouris, Ally Kisiel, Valentino Sorto, Julia Mauro, Graham Collier

Symposium of Student Scholars

Electrochromic materials have found widespread use in consumer electronics, energy saving windows, and military applications. They contain unique electronic properties allowing them to undergo a color change in a redox reaction. One classification of these molecules is known as anodically coloring electrochromes (ACEs). When in solution, these compounds are transmissive in the neutral (ground) state and absorb visible light upon oxidation, by the formation of a radical cation, thus making them colored. The focus of this study is the electronic transitions of this radical cation and how chemical modifications to the structures produce a variable color profile. To design prospective …

Designing And Synthesizing A Warhead-Fragment Inhibitory Ligand For Ivyp1 Through Fragment-Based Drug Discovery, Samuel Moore

Symposium of Student Scholars

Fragment-based drug discovery (FBDD) is a powerful tool for developing anticancer and antimicrobial agents. Within this, magnetic resonance spectroscopy (NMR) provides a comprehensive qualitative and quantitative approach to screening and validating weak and robust binders with targeted proteins, making NMR among the most attractive strategies in FBDD. Inhibitor of vertebrate lysozyme (Ivyp1) of P. aeruginosa serves as an excellent target because of its active cellular location and implications in clinical prognosis for cystic fibrosis and immunocompromised patients. This study uses current NMR and biophysical techniques to develop a covalent, fragment-linked warhead inhibitor for Ivyp1 through synthetic methods, warhead linking, and …

Efforts Towards The Asymmetric De Novo Synthesis Of Lanostanes And Euphanes, Htoo Tint Wai

Dartmouth College Ph.D Dissertations

Tetracyclic triterpenoids are ubiquitous in nature and biology, with members displaying a wide range of medically relevant properties and occupying rather distinct regions of chemical space. Members of this large class include well-known steroid hormones and sterols as well as structurally interesting subclasses such as lanostanes and euphanes, among others. Comprised of the tetracyclic skeleton with three stereodefined quaternary centers at ring-junction positions, lanostanes and euphanes present synthetic challenges that are different from those encountered in efforts targeting the structurally less complex steroid hormones. Lanostanes, in particular, stand as a historically important class of compounds as significant attention has been …

The Spectral Features And Detectability Of Small, Cyclic Silicon Carbide Clusters, Christopher M. Sehring, C. Zachary Palmer, Brent R. Westbrook, Ryan C. Fortenberry

Faculty and Student Publications

Rovibrational spectral data for several tetra-atomic silicon carbide clusters (TASCCs) are computed in this work using a CCSD(T)-F12b/cc-pCVTZ-F12 quartic force field. Accurate theoretical spectroscopic data may facilitate the observation of TASCCs in the interstellar medium which may lead to a more complete understanding of how the smallest silicon carbide (SiC) solids are formed. Such processes are essential for understanding SiC dust grain formation. Due to SiC dust prevalence in the interstellar medium, this may also shed light on subsequent planetary formation. Rhomboidal Si2C2 is shown here to have a notably intense (247 km mol−1) anharmonic vibrational frequency at 988.1 cm−1 …

Probing Conformational Landscapes And Mechanisms Of Allosteric Communication In The Functional States Of The Abl Kinase Domain Using Multiscale Simulations And Network-Based Mutational Profiling Of Allosteric Residue Potentials, Keerthi Krishnan, Hao Tian, Peng Tao, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

In the current study, multiscale simulation approaches and dynamic network methods are employed to examine the dynamic and energetic details of conformational landscapes and allosteric interactions in the ABL kinase domain that determine the kinase functions. Using a plethora of synergistic computational approaches, we elucidate how conformational transitions between the active and inactive ABL states can employ allosteric regulatory switches to modulate intramolecular communication networks between the ATP site, the substrate binding region, and the allosteric binding pocket. A perturbation-based network approach that implements mutational profiling of allosteric residue propensities and communications in the ABL states is proposed. Consistent with …

Synthesis And Surface Modification Of Azide Decorated Silver Nanoclusters, Alexander H. Stöckli

Electronic Thesis and Dissertation Repository

In nanocluster research, easy modification of the cluster surface while maintaining the cluster core remains a key challenge. Herein we report the synthesis, structure, and properties of four targeted Ag₂₀ nanoclusters (NCs) with surface azide moieties, two of which have 8 azide moieties, [CO₃@Ag₂₀(S^tBu)₁₀(m-N₃-C₆H₄COO)₈(DMF)₄] and [CO₃@Ag₂₀(S^tBu)₁₀(p-N₃-C₆H₄COO)₈(DMF)₄], and two of which have 6 azide moieties, [CO₃@Ag₂₀(S …

Wrack Lines Volume 22, Number 2, Fall-Winter 2022-2023, Nancy C. Balcom, Juliana Barrett, Judy Benson, Ben Crnic, Sto Len

Wrack Lines

With the theme, "Looking Ahead: People and Projects Shaping the Future," the Fall-Winter 2022-2023 leads with the first in what will be a series of articles about offshore wind development impacting Connecticut. That is followed by the inspiring story of how a dying forest was replanted for climate resilience. Next, a profile of longtime marine educator Tim Visel tells about his lasting impact on Connecticut schools and students. Lastly, the complex challenge of dealing with Contaminants of Emerging Concern is examined, with descriptions of how Sea Grant is involved and the particularly troublesome group of substances called PFAS.

A Human Oral Fluid Assay For D- And L- Isomer Detection Of Amphetamine And Methamphetamine Using Liquid-Liquid Extraction, Brian Robbins, Rob E. Carpenter, Mary Long, Jacob Perry

Human Resource Development Faculty Publications and Presentations

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step …

Controlling Polymer Molecular Structure And Morphology: From Illumination Of Conjugated Polymers To Polymer Chain Depolymerization, Josh Moncada

Doctoral Dissertations

Polymers remain a prominent component of our lives, and finding methods to control their structure or morphology are needed to tune material properties. This dissertation reports methods to alter the conformation, morphology, or structure of polymeric materials. Chapter two describes the impact of exposure to white light during annealing of conjugated polymer blends on their morphology and optoelectronic performance. The observed changes in the morphology correlate strongly to the variation in photoluminescence (PL) with illumination, including that the PL varies less with illumination at higher Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] loadings, offering foundational understanding to guide the structure and optoelectronic performance of conjugated polymer …

Light Matter Interactions: A Study Of Soft Materials Using Linear And Nonlinear Spectroscopy, Muhammad Redwan Hassan

Doctoral Dissertations

The adoption of complex fluids for various industrial applications is becoming normal. Complex fluids offer tunability, wide range solubility, and chemical and thermal stability which are the factors that conventional polar and non-polar solvents often lack. However, fundamental studies of these fluid systems are still lacking which is limiting the appropriate use of these complex fluids in many applications. The goal of this dissertation was to study and characterize complex fluids for application in electrolytes for redox flow batteries. Chapter 3 and chapter 4 feature the study of microemulsions and deep eutectic solvents (DES) by fluorescence techniques. Fluorescence studies of …

Transition Metal Computational Catalysis: Mechanistic Approaches And Development Of Novel Performance Metrics, Brett Anthony Smith

Doctoral Dissertations

Computational catalysis is an ever-growing field, thanks in part to the incredible progression of computational power and the efficiency offered by our current methodologies. Additionally, the accuracy of computation and the emergence of new methods that can decompose energetics and sterics into quantitative descriptors has allowed for researchers to begin to identify important structure-function relationships that predict the properties of unexplored subspaces within the overall chemical space. Catalytic descriptors have been used frequently in data driven high-throughput computational screenings. With the use of machine learning, a large portion of the chemical space an be predicted in matter of minutes or …

Designing Single Molecule Diode, Tinsae Alem

Longwood Senior Theses

The field of single molecule electronics is based on using single molecule devices to control current in electronic circuits. One area of interest is to reproduce the functionality of traditional components such as wires, switches, and diodes using single molecule junctions. We used computational chemistry to design diodes to investigate what molecular features affect their performance including using different donors, acceptors, and connectors. A comparison of the diode's performance was made by comparing the rectification ratio. About 50 diodes were designed and tested, with rectification ratios ranging from 1.0 to 5.8. The results indicate that multiple factors have a significant …

Achieving Safe Use Of Advanced Materials In Drinking Water Through Novel Nano Analytics And Enabling Electrification Using Green Catalyst, Kenneth Ray Flores

Open Access Theses & Dissertations

The accumulation of engineered nanomaterials (ENMs) in environmental sectors will continue to increase as more applications are discovered for their unique properties and characteristics. Additionally, the presence of nanomaterials in the environment becomes exacerbated as more consumer products containing nanoparticles are approved for use. It is debated whether the toxic effects of nanoparticles stem from the particles themselves, ionic species, or formation of secondary particles. Therefore, understanding the behavior of nanoparticles in the environment becomes key to discerning the toxicological effects of nanoparticles. Many advancements have been made with ICP-MS to understand the behavior of nanoparticles in the environmental systems, …