Comparison Of The Vibrational Modes Of Thiolated Gold Nanoparticles Undergoing Core-Conversions Via Raman Spectroscopy, 2020 University of Mississippi
Comparison Of The Vibrational Modes Of Thiolated Gold Nanoparticles Undergoing Core-Conversions Via Raman Spectroscopy, William Gregory Cannella Jr.
In this project, the vibrational characteristics/vibrational modes are explored via Raman Spectroscopy for thiolated-gold nanoparticles. This class of compounds is also known as gold nanoparticles (AuNPs). They remain of great interest in research areas such as catalysis, gold dependent nanoelectronics, drug delivery, and sensing, due to their unique size-dependent optical, chiroptical, and electronic properties. Vibrational spectroscopy of thiolated gold nanoparticles are oftentimes considered nontrivial as the compounds strongly absorb light in the visible region of the electromagnetic spectrum, are generally considered weak scatterers, and give off large amounts of fluorescence. This combined with their black appearance, susceptibility to localized ...
Study Of Pharmaceutical Tablets Using Raman Mapping, 2020 University of Mississippi
Study Of Pharmaceutical Tablets Using Raman Mapping, Kyle Joseph Pauly
Covalent bonds are the strongest type of bonds holding molecules together. Based on the pattern of bonding of the molecule, the atoms associated with the bond will vibrate at a specific frequency. Utilizing vibrational spectroscopy, such as Raman spectroscopy, these unique vibrational frequencies can be used to detect the presence of analytes over a selected area. Furthermore, the intensities of the vibrational modes can be tracked to comparatively quantify the concentration of analytes at various locations. This is a method of great importance due to its ability to compare pharmaceutical tablets synthesized with different techniques. Here, the presence and concentration ...
Characterizing The Long-Range And Short-Range Interactions Stabilizing A Model Sh3 Recognition Complex, Colin Mcclure
Chemistry Senior Theses
SH3 domains are common recognition domains found in many protein complexes of all eukaryotes. Their regulatory functions are involved in cell proliferation, differentiation, cytoskeleton modification and are vital for cellular communication. We have used Molecular Dynamics (MD) simulations to computationally model a common interaction between the AbpSH3 domain and the intrinsically disordered peptide, ArkA. This work is in collaboration with and in support of previous experimental studies of the complex aimed to characterize the binding pathway including NMR, ITC, and chemical denaturation. Specifically, my work focuses on the long-range electrostatic interactions involved in stabilizing the bound AbpSH3- ArkA complex. Previous ...
Raman Spectroscopy Study Of Delta-9-Tetrahydrocannabinol And Cannabidiol And Their Hydrogen-Bonding Activities, 2020 University of Mississippi
Raman Spectroscopy Study Of Delta-9-Tetrahydrocannabinol And Cannabidiol And Their Hydrogen-Bonding Activities, Kalee Sigworth
Cannabis and products containing its cannabinoids have grown rapidly in acceptance and use in recent years with legalization of cannabis in many countries and US states. Cannabidiol and Delta-9-Tetrahydrocannabinol are two primary cannabinoids in Cannabis that have been shown to produce analgesic effects along with many other positive side effects for the user. These two cannabinoids interact with receptors in the Central and Peripheral Nervous Systems. No spectroscopic study to our knowledge has been performed to analyze the hydrogen bonding effects of interactions between these two cannabinoids and solvents. Here, we employ theoretical Raman spectra through computational methods to study ...
Spectral Narrowing Accompanies Enhanced Spatial Resolution In Saturated Coherent Anti-Stokes Raman Scattering (Cars): Comparisons Of Experiment And Theory, Avinash Singh, Kalyan Santra, Xueyu Song, Jacob W. Petrich, Emily A. Smith
We demonstrate theoretically and confirm experimentally the mechanism by which spectral narrowing accompanies enhanced spatial resolution in a saturated coherent anti-Stokes Raman scattering (CARS) signal that is demodulated at the third harmonic (3f) of the pump modulation frequency (f). Under these modulation conditions, theory predicts a narrowing of the full width at half-maximum (FWHM) of the CARS spectrum by a factor of 2.0 with respect to that of the spectrum obtained by demodulation at the fundamental frequency. Theory also predicts an improvement of spatial resolution by a factor of 1.7. Experimentally, narrowing of the FWHM of the ...
Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, 2020 Chapman University
Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn E. Merrill, Bingjie Zhang, Jerry Larue
Student Scholar Symposium Abstracts and Posters
Catalysis provides pathways for efficient and selective chemical reactions through the lowering of energy barriers for desired products. Gold nanoparticles (AuNP) show excellent promise as plasmonic catalysts. Localized surface plasmon resonances are oscillations of the electron bath at the surface of a nanoparticle that generate energetically intense electric fields and rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize strongly bound oxygen atoms through occupation of accessible anti-bonding orbitals. Tuning the anti-bonding orbitals to make them accessible for occupancy will be achieved by coating the AuNP in a thin layer of another transition metal, such ...
Raman Spectroscopic And Quantum Chemical Investigation Of The Effects Of Tri-Methylamine N-Oxide (Tmao) On Hydrated Urea, Hydrated Guanidinium, And Hydrogen Bonded Networks, 2020 University of Mississippi
Raman Spectroscopic And Quantum Chemical Investigation Of The Effects Of Tri-Methylamine N-Oxide (Tmao) On Hydrated Urea, Hydrated Guanidinium, And Hydrogen Bonded Networks, Genevieve Verville
Trimethylamine N-Oxide (TMAO), guanidinium, and urea are three important
osmolytes with their main significance to the biophysical field being in how they
uniquely interact with proteins. TMAO is known to stabilize and counteract the
destabilizing effects of both urea and guanidinium. The exact mechanisms by which
TMAO stabilizes and both guanidinium and urea destabilize folded proteins continue
to be debated in the literature. Some studies suggest that solvent interactions do not
play a large role in TMAO’s stabilizing effects and therefore advocate direct
stabilization, whereas others suggest that TMAO counteracts denaturation primarily
through an indirect effect of strong solvent ...
Adaptation Of A Low-Cost Hyperpolarization Technique For Use With Single-Sided Nmr, 2020 William & Mary
Adaptation Of A Low-Cost Hyperpolarization Technique For Use With Single-Sided Nmr, Ruth A. Beaver
Undergraduate Honors Theses
Nuclear magnetic resonance (NMR) suffers from inherent signal problems due to low levels of nuclear polarization at room temperature. These problems are especially prevalent in single-sided NMR, which allows for a more flexible measurement geometry and simpler, cheaper instrumentation than traditional NMR. Hyperpolarization techniques can remedy this by providing artificially high levels of polarization for a single measurement. Signal Amplification By Reversible Exchange (SABRE) hyperpolarization is particularly advantageous, since it can be produced quickly using relatively cheap and simple instrumentation. While SABRE hyperpolarization has been successfully demonstrated with traditional NMR, it has not yet been adapted for single-sided NMR. Here ...
Spectroscopic And Computational Studies Of The Agricultural Active Ingredient Dicamba, 2020 University of Mississippi
Spectroscopic And Computational Studies Of The Agricultural Active Ingredient Dicamba, James Johnson
3,6-dichloro-2-methoxy benzoic acid, more commonly known as Dicamba, is the active ingredient in an array of pesticides used on farmlands across the globe. Dicamba’s mode of action works by mimicking the plant hormone auxin, which is synonymous to growth hormones in mammals. The mimicking of auxin results in excessive elongation and growing, which is eventually fatal for plants when the rate of growth can no longer be sustained. Dicamba has risen in prominence in recent years due to drift damage as a result of Dicamba’s high volatility. Having the ability to identify Dicamba is crucial for the ...
Surface Chemistry And Surface Properties Of Energetic Nitrocellulose (Nc), 2020 Seton Hall University
Surface Chemistry And Surface Properties Of Energetic Nitrocellulose (Nc), Henry Grau
Seton Hall University Dissertations and Theses (ETDs)
This research describes an investigation into the wettability of nitrocellulose (NC), most importantly to nitroglycerin (NG), which are key components of formulations used to propel military ammunition. NG demonstrates complete wetting of NC and, overtime, NG sweats on the NC surface and leaks out. The leaking out of NG from the solid formulation is a known cause of fires and explosions resulting from storage. The origin of this research is inspired by the need to engineer a solution to leakage problems of energetic plasticizer in NC based propellant. While searching for a viable material for a specific application, we journeyed ...
An Investigation Into The Molecular Dynamics Of The Laser Induced Dissociation Of 2-Bromoethanol, 2020 Liberty University
An Investigation Into The Molecular Dynamics Of The Laser Induced Dissociation Of 2-Bromoethanol, Kirk French
Senior Honors Theses
The unimolecular dissociation of 2-bromoethanol is investigated using computational chemistry methods both to test the reliability of the theories and methods of computational chemistry and to explore the internal mechanism of the dissociation. The dissociation of the bromine ion from 2-bromoethanol was experimentally observed in a previous publication by Ratliff et. al. These experimental results were compared in this thesis to computational calculations of their research. The method of TD-B3LYP proved to be inadequate in this venture except for the lowest energies of the most stable conformer of 2-bromoethanol. However, interesting mechanisms were found such as the formation of HBr ...
354— Observation Of Acid Penetration Of Nano-Gold Doped Sol-Gel System, 2020 SUNY Geneseo
354— Observation Of Acid Penetration Of Nano-Gold Doped Sol-Gel System, Mir Ali, Eric Koessler
The penetration of the acid into gold doped sol-gel material was measured. The acid penetration speed increased as the nano size increased up from 5 nm to 20 nm. Then there was almost no penetration at 60 nm. The nano dependent rate change was complex and needs to be investigated further. Also, recent new methodology to create the gel showed a significance stability and it took more than a few days to complete the penetration.
Monitoring And Identifying The Rhodamine 6g-Hydroxide Ion Reaction Using In-Situ, Surface-Enhanced Raman Spectroscopy, 2020 Western Kentucky University
Monitoring And Identifying The Rhodamine 6g-Hydroxide Ion Reaction Using In-Situ, Surface-Enhanced Raman Spectroscopy, Ryan Lamb
Masters Theses & Specialist Projects
An effective method for monitoring chemical reactions is necessary to better understand their mechanisms and kinetics. Effective reaction monitoring requires a spectroscopy technique with fast data acquisition, high sensitivity, structure-to-spectrum correlation, and low solvent interference. Surface-enhanced Raman spectroscopy (SERS) provides these features, which makes it a valuable tool for monitoring reactions. To obtain the Raman enhancement, metallic nanostructures typically made of silver or gold are aggregated using a salt. The nanoparticles aggregates must then be stabilized using a surfactant to use this method in situ due to eventual nanoparticle precipitation. In this study, gold nanoparticles stabilized with sodium dodecyl sulfate ...
Fundamentals Of Au(111) Surface Dynamics: Coarsening Of 2d Au Islands, 2020 Iowa State University
Fundamentals Of Au(111) Surface Dynamics: Coarsening Of 2d Au Islands, Peter M. Spurgeon, King C. Lai, Yong Han, James W. Evans, Patricia A. Thiel
Au(111) surfaces play a central role in many applications, yet studies of fundamental aspects of their dynamics are limited. Thus, using Scanning Tunneling Microscopy (STM) at 300 K, we analyze the coarsening of first-layer 2D Au islands directly on the Au(111) substrate, and also of second-layer 2D Au islands. Specifically, we monitor the decay of Au first-layer islands with areas of about 100-500 nm^2 in the vicinity of larger islands or extended step edges over a period of approximately 40 hours - the relevant time scale for this process. Experimentally observed behavior is captured by analytic theory for ...
Adsorption, Intercalation, Diffusion, And Adhesion Of Cu At The 2h−Mos2 (0001) Surface From First-Principles Calculations, 2020 Iowa State University and Ames Laboratory
Adsorption, Intercalation, Diffusion, And Adhesion Of Cu At The 2h−Mos2 (0001) Surface From First-Principles Calculations, Yong Han, Michael C. Tringides, James W. Evans, Patricia A. Thiel
Study of the adsorption of a transition metal on the surface of a layered material and the possible subsequent intercalation into that layered material is of fundamental interest and potential technological importance. In the present work, we choose the transition metal Cu as the adsorbate or intercalant and 2H-MoS2 as the layered material. Energetics are calculated characterizing four of the most basic surface and interfacial phenomena: adsorption, intercalation, diffusion, and adhesion. Using first-principles density functional theory (DFT), we find that intercalating a Cu atom into the van der Waals (vdW) gap below the MoS2 (0001) surface is 0.665 eV ...
Study Of Reaction Dynamics Of Protonated/Deprotonated And Radical Cations Of Guanine In Nucleobases And Nucleosides: Singlet Oxygen Oxidation, C8-Water Addition, Cross-Linking With Lysine And Base-Pair Dissociation, 2020 The Graduate Center, City University of New York
Study Of Reaction Dynamics Of Protonated/Deprotonated And Radical Cations Of Guanine In Nucleobases And Nucleosides: Singlet Oxygen Oxidation, C8-Water Addition, Cross-Linking With Lysine And Base-Pair Dissociation, Yan Sun
All Dissertations, Theses, and Capstone Projects
Among the four DNA nucleobases, guanine (G) has the lowest oxidation potential and represents a preferential target for oxidation and ionization. This leads to the formation of guanine radical cation (G•+) in various oxidative environments. Of the biologically relevant oxidants, electronically excited singlet oxygen (1O2) exclusively damages the guanine bases and gives rise to mutagenesis, DNA-protein cross-linking and cellular death. Combining our home-made electrospray ionization (ESI) guided-ion-beam tandem mass spectrometer, with reaction potential surface calculations and kinetics modeling, five projects have been accomplished as described below.
In project 1, the reactions of deuterated water (D2O) with ...
In Situ Monitoring Of Catalytic Molecular Transformations On Noble Metal Nanocatalysts Using Surface-Enhanced Raman Spectroscopy, 2020 University of South Carolina
In Situ Monitoring Of Catalytic Molecular Transformations On Noble Metal Nanocatalysts Using Surface-Enhanced Raman Spectroscopy, Hui Wang, Qingfeng Zhang, Esteban Villarreal, Hao Jing, Kexun Chen
Journal of the South Carolina Academy of Science
Noble metal nanoparticles have long been of tremendous interest in the nanophotonics and nanocatalysis communities owing to their intriguing size- and shape-dependent plasmonic and catalytic properties. The combination of tunable plasmon resonances with superior catalytic activities on the same noble metal nanoparticle, however, has long been challenging because the research on nanoplasmonics and nanocatalysis deals with nanoparticles in two drastically different size regimes. While tunable plasmon resonances are a unique feature of metallic nanoparticles in the sub-wavelength size regime, heterogeneous catalysis requires the use of substrate-supported sub-5 nm nanoparticulate catalysts. In this mini-review article, we share with the readers several ...
Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, 2020 Washington University in St. Louis
Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler
Electrical & Systems Engineering Publications and Presentations
Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of ...
Modeling The Oh-Initiated Oxidation Of Mercury In The Global Atmosphere Without Violating Physical Laws, Theodore Dibble, Hanna L. Tetu, Khoa T. Lam, Colin P. Thackray, Daniel J. Jacob
Chemistry Faculty Scholarship
In 2005, Calvert and Lindberg wrote that the use of laboratory-derived rate constants for OH + Hg(0) “…to determine the extent of Hg removal by OH in the troposphere will greatly over-estimate the importance of Hg removal by this reaction.” The HOHg• intermediate formed from OH + Hg will mostly fall apart in the atmosphere before it can react. By contrast, in laboratory experiments, Calvert and Lindberg expected HOHg• to react with radicals (whose concentrations are much higher than in the atmosphere). Yet almost all models of oxidation of Hg(0) ignore the argument of Calvert and Lindberg. We present a ...
Development Of A Novel Highly-Sensitive Brucellosis Sensor Based On Surface Plasmon Resonance Spectroscopy, 2020 The British University in Egypt
Development Of A Novel Highly-Sensitive Brucellosis Sensor Based On Surface Plasmon Resonance Spectroscopy, Amal Kasry, Ihab Adly, Asharf Sayour, Hossam Sayour
Nanotechnology Research Centre
Brucellosis is considered a significant health threat, it is an infectious disease caused by the bacteria Brucella, which can spread from animals to humans causing severe diseases. Through this project, we aim to develop a very highly sensitive biosensor to detect Brucella early before spreading. This sensor is based on surface plasmon resonance (SPR) technique, which is used to analyze kinetics of interaction between biomolecules. It can detect down to picomolar concentrations of some proteins.