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2021

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Articles 421 - 450 of 1742

Full-Text Articles in Chemistry

Determination Of The Kinetic Roles Of The Membrane In The Catalysis Of Rasgefs By Using An Engineered Model Protein, Hanh My Hoang Aug 2021

Determination Of The Kinetic Roles Of The Membrane In The Catalysis Of Rasgefs By Using An Engineered Model Protein, Hanh My Hoang

Chemistry & Biochemistry Dissertations - Archive

Ras guanine nucleotide exchange factors (RasGEFs), which include Son of Sevenless (SOS), Ras Guanine Nucleotide Releasing Protein (RasGRP), and Ras Guanine Nucleotide Releasing Factor (RasGRF), catalyze nucleotide exchange of Ras upon activating signals. Crystal structure analyses suggest that catalytic cavities of RasGEFs are not deep enough to uphold their substrates. Given that RasGEFs are all membrane binding proteins, a novel “membrane supplement hypothesis” is proposed that RasGEFs in cytoplasm are catalytically unformed; and RasGEFs on membrane are catalytically competent. The reason RasGEFs are catalytically unformed without the support of membrane is because the catalytic sites of RasGEFs are not sufficiently …

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New Flexible Moldable Ion-Exchange Polymers And Their Analytical Applications, Fereshteh Maleki Aug 2021

New Flexible Moldable Ion-Exchange Polymers And Their Analytical Applications, Fereshteh Maleki

Chemistry & Biochemistry Dissertations - Archive

This dissertation aims to improve the functionality of open tubular capillary ion chromatography (OTIC) in terms of the lower limit of detection (LOD) and higher sensitivity by fabricating a microchannel suppressor and integrating it into an OTIC system. To reach the goal, an ion-exchange membrane (IEM) was formulated and developed using aqueous solutions environmentally friendly chemicals. The PVA-SS polymer is made from poly vinyl alcohol (PVA) as the polymer matrix and styrene sulfonate sodium salt (SS) as the ionic functional group (the salt-form polymer is eventually converted to acidic form), referred to here mostly as PVA-SS polymers. The new IEM …

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Improved Fischer-Tropsch Synthesis By Thermal Management Of The Catalyst, Seyed Amir Jafari Ghoreshi Aug 2021

Improved Fischer-Tropsch Synthesis By Thermal Management Of The Catalyst, Seyed Amir Jafari Ghoreshi

Chemistry & Biochemistry Dissertations - Archive

The research in this dissertation consists of a novel catalyst design which is aimed at helping manage the temperature instabilities and heat-transfer within a catalyst particle and maintaining an isothermal temperature distribution throughout the catalyst bed, with the goal of improving control on the rate of reactions and tuning the chain propagation that leads to having high yields of desired products (liquid alkanes C5-C22) while suppressing undesirable competitive reactions (WGS, Boudouard) and consecutive byproduct formation (alpha-Olefin, Oxygenates, and tail gas C1-C4) during the Fischer-Tropsch synthesis (FTS). Comparing FTS performance of the thermally modified catalysts and core-shell (CS) composite structure catalyst …

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Continuously Renewed Copper Electrode For Amperometric Measurement Of Carbohydrates, Shane R. Wilson Aug 2021

Continuously Renewed Copper Electrode For Amperometric Measurement Of Carbohydrates, Shane R. Wilson

Chemistry & Biochemistry Theses - Archive

Currently the benchmark method for carbohydrate analysis in a variety of application areas involves anion exchange chromatography followed by electrochemical detection at a gold electrode. The gold electrode surfaces foul from deposition of oxidation products over time; pulsed waveforms with oxidative cleaning and surface reduction are used to improve electrode longevity. After fouling, the electrode needs polishing, or, if using disposable gold electrodes, replacement; both remedies require subsequent recalibration. I describe here a novel electrochemical amperometric detector using a copper electrode that is consumed during the measurement process and a new surface is continuously generated without a change in the …

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Studies On Enantioselective Desymmetrizing Alkyne Hydrosilylation, Yao Chung Chang Aug 2021

Studies On Enantioselective Desymmetrizing Alkyne Hydrosilylation, Yao Chung Chang

Chemistry & Biochemistry Theses - Archive

This research focuses on the design and synthesis of enantioselective desymmetrizing α-hydrosilylation of propargyl alcohols to provide α-hydroxy (E)-vinylsilanes. Transition metal-catalyzed, regio-and stereoselective intramolecular hydrosilylation of propargylic alcohols with an easily removable acetal directing group has been studied. This project thus far screened 35 chiral ligands with rhodium (I) to achieve enantioselective alkyne hydrosilylation. This strategy consists of sequential hydrosilylation of bis-propargyl formate with iridium catalyst and intramolecular alkyne hydrosilylation with chiral rhodium catalyst. To this end, a variety of chiral phosphine ligands has been tested, yet an enantiomeric excess of the α-hydroxy (E)-vinylsilanes has not been fruitful thus far, …

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Prospective Chemistry Teachers’ Evaluations About The Instruction Of The Graphic Organizers Course, Canan Nakiboglu Aug 2021

Prospective Chemistry Teachers’ Evaluations About The Instruction Of The Graphic Organizers Course, Canan Nakiboglu

University of South Florida (USF) M3 Publishing

Graphic organizers (GOs) are visual teaching and learning tools that provide an organized expression of knowledge by explaining concepts and events. If the teachers incorporate the GOs into their lessons as instructional material and assessment tools, they can make the teaching period more effective and also help their students' understanding of the chemistry subjects. In this study, the prospective chemistry teachers (PCTs) attended a Graphic Organizers Course, and then their opinions regarding the evaluation of the course were taken. A total of 43 PCTs, 32 female and 11 male, who took the course in four different semesters, participated in this …

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Comparison Of Supported Liquid Extraction And Solid Phase Extraction Of Methamphetamine From Urine And Method Validation By Gas Chromatography-Mass Spectrometry, Taylor Hood Aug 2021

Comparison Of Supported Liquid Extraction And Solid Phase Extraction Of Methamphetamine From Urine And Method Validation By Gas Chromatography-Mass Spectrometry, Taylor Hood

Master's Theses

Applications of SLE (supported liquid extraction) is a relatively new extraction technique that is not widely used in forensic toxicology. SLE is also easier and less time consuming than traditional LLE (liquid-liquid extraction) and SPE (Solid phase extraction). This work will compare the extraction efficiencies between SLE and SPE for methamphetamine from urine with detection and quantitation using GC-MS (gas chromatography- mass spectrometry). The SLE cartridges provide better analyte recoveries, eliminate emulsion formation, and allow for shorter processing time than other extraction techniques. The SPE cartridges used have a mixed-mode non-polar/strong cation exchange retention mechanism to extract basic analytes like …

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Tuning The Solubility, Cellular-Uptake And Activity Of Microtubule Stabilizing Ruthenium Polypyridyl Complexes, Melissa Marie Reardon Aug 2021

Tuning The Solubility, Cellular-Uptake And Activity Of Microtubule Stabilizing Ruthenium Polypyridyl Complexes, Melissa Marie Reardon

Chemistry & Biochemistry Theses - Archive

Many Ru(II) Polypyridyl Complexes (RPCs) are being investigated as they show potent cytotoxicity and acceptable toleration in animals. Some of these RPCs are thought to target DNA and/or mitochondria in cells. Recently, [Ru(dip)3]2+ (dip= 4,7-diphenylphenanthroline) with cytotoxicity ranging from 1-4 µM, has shown to target microtubules (MTs) and exhibit strong microtubule stabilizing activity (MSA). Determination of [Ru(dip)3]2+:MT stoichiometry was difficult due to poor solubility. Therefore, to study this new metallo-organic target, a less lipophilic RPC is needed to enhance solubility, while still achieving cytotoxicity. The purpose of this thesis is to test the following hypothesis. We postulate that by systematically …

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Preparation And Characterization Of Silver And Copper Vanadates, Abbas Vali Aug 2021

Preparation And Characterization Of Silver And Copper Vanadates, Abbas Vali

Chemistry & Biochemistry Dissertations - Archive

Combining two or more binary compounds to generate a multinary compound is a viable strategy to improve the performance and properties of the parent binary compounds. In this vein, multinary compound semiconductors have recently come under the spotlight for a variety of practical device applications. In particular, the low band gaps of the Ag-V-O ternary family (Ag3VO4, Ag4V2O7, AgVO3, Ag2V4O11, and AgV7O18) and Cu(II)-V-O ternary family (CuV2O6, Cu2V2O7, Cu3V2O8, Cu11V6O26, and Cu5V2O10) have recently garnered interest. These visible light active semiconductors may be used for photovoltaic solar cells, solar water splitting, CO2 photoreduction, and photocatalytic remediation applications. In particular, AgVO3 …

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Vortex-Oriented Ferroelectric Domains In Snte/Pbte Monolayer Lateral Heterostructures, Kai Chang, John W. D. Villanova, Jing-Rong Ji, Souvik Das, Felix Kuster, Salvador Barraza-Lopez, Paolo Sessi, Stuart S. P. Parkin Aug 2021

Vortex-Oriented Ferroelectric Domains In Snte/Pbte Monolayer Lateral Heterostructures, Kai Chang, John W. D. Villanova, Jing-Rong Ji, Souvik Das, Felix Kuster, Salvador Barraza-Lopez, Paolo Sessi, Stuart S. P. Parkin

Physics Faculty Publications and Presentations

Heterostructures formed from interfaces between materials with complementary properties often display unconventional physics. Of especial interest are heterostructures formed with ferroelectric materials. These are mostly formed by combining thin layers in vertical stacks. Here the first in situ molecular beam epitaxial growth and scanning tunneling microscopy characterization of atomically sharp lateral heterostructures between a ferroelectric SnTe monolayer and a paraelectric PbTe monolayer are reported. The bias voltage dependence of the apparent heights of SnTe and PbTe monolayers, which are closely related to the type-II band alignment of the heterostructure, is investigated. Remarkably, it is discovered that the ferroelectric domains in …

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Synthesis And Characterization Of Novel Organic Ligands With Their Complexes Of Platinum, Copper And Uranium, Mustafa Adnan Yasin Aldulaimi Aug 2021

Synthesis And Characterization Of Novel Organic Ligands With Their Complexes Of Platinum, Copper And Uranium, Mustafa Adnan Yasin Aldulaimi

Dissertations

Transition metal complexes of symmetrical and asymmetrical Schiff bases have played a significant role in the field of coordination, inorganic, and bioinorganic chemistry as models for biological, analytical, industrial, and pharmaceutical applications. Over recent years a great deal of interest has developed in new transition metal complexes of Schiff base ligand. The preparation of novel organic ligands is the most important step in the development of metal complexes that exhibit unique properties and novel reactivity. To highlight the presentation of this dissertation and to provide more detailed investigations, the dissertation was separated into six chapters according to the sequence of …

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Cyclic Sulfones From Double Conjugate Addition Of Rongalite, Hao Zong Aug 2021

Cyclic Sulfones From Double Conjugate Addition Of Rongalite, Hao Zong

Theses, Dissertations and Culminating Projects

We report a cyclic sulfone synthesis method from the addition of sodium hydroxymethanesulfinate to doubly electrophilic dienone substrates. The novel synthesis of the cyclic sulfone thus avoided the using the toxic and odorous sulfides, and also oxidizing reagents. We prepared both the symmetrical and unsymmetrical substrates, and then used the substrate for the synthesis of cyclic sulfone.

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Molecular Simulation Of Rna Conformational Dynamics : An Example Of Micro-Rna Targeting Messenger Rna : Mir-34a-Msirt1, Parisa Ebrahimi Aug 2021

Molecular Simulation Of Rna Conformational Dynamics : An Example Of Micro-Rna Targeting Messenger Rna : Mir-34a-Msirt1, Parisa Ebrahimi

Legacy Theses & Dissertations (2009 - 2024)

MicroRNA (miRNA), as a distinct class of biological regulators and a ”guide” member of non-coding RNA-protein complexes (RNPs), regulates more than 60% of protein-coding genes expression through base-pairing with targeted messenger RNA (mRNA) in the RNA-Induced Silencing Complex (RISC). Most of miRNAs identified in human, are conserved in other animals, which have preferentially conserved interaction sites particularly in 3’ untranslated regions (3’UTRs) of many human messenger mRNAs.The capability of a single miRNA to target more than hundreds of mRNAs, suggests that miRNAs influence essentially all developmental process and diseases, which also makes them interesting candidates as therapeutics agents. The primary …

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Two Dimensional Nanoparticles/Nanozymes For Biosensing Augmented By Machine Learning, Nidhi Chintan Nandu Aug 2021

Two Dimensional Nanoparticles/Nanozymes For Biosensing Augmented By Machine Learning, Nidhi Chintan Nandu

Legacy Theses & Dissertations (2009 - 2024)

Biosensing is an ever-evolving field with many resources devoted towards new approaches in sensing and refining the existing methods. For a long time, such approaches involved use of state-of-the-art instruments and were often proved to be time consuming and expensive. Nanoparticles with their unique properties, inexpensive synthesis and ease of manipulation have found purpose in myriad fields including biosensing. Different nanoparticles based on their composition, morphology, dimensionality, and surface modifications have already gained foot hold in the biosensor ranks. The unique opto-electric properties due to the quantum effect in the nanoparticles have also made them one of the leading alternatives …

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Molecular Simulation Of Rna Conformational Dynamics : An Example Of Micro-Rna Targeting Messenger Rna : Mir-34a-Msirt1, Parisa Ebrahimi Aug 2021

Molecular Simulation Of Rna Conformational Dynamics : An Example Of Micro-Rna Targeting Messenger Rna : Mir-34a-Msirt1, Parisa Ebrahimi

Legacy Theses & Dissertations (2009 - 2024)

MicroRNA (miRNA), as a distinct class of biological regulators and a ”guide” member of non-coding RNA-protein complexes (RNPs), regulates more than 60% of protein-coding genes expression through base-pairing with targeted messenger RNA (mRNA) in the RNA-Induced Silencing Complex (RISC). Most of miRNAs identified in human, are conserved in other animals, which have preferentially conserved interaction sites particularly in 3’ untranslated regions (3’UTRs) of many human messenger mRNAs.The capability of a single miRNA to target more than hundreds of mRNAs, suggests that miRNAs influence essentially all developmental process and diseases, which also makes them interesting candidates as therapeutics agents. The primary …

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Targeted And Untargeted Chromatography-Mass Spectrometry Methods For Alcoholic Beverage Analysis, Hailee Elizabeth Ratcliffe Aug 2021

Targeted And Untargeted Chromatography-Mass Spectrometry Methods For Alcoholic Beverage Analysis, Hailee Elizabeth Ratcliffe

Chemistry & Biochemistry Dissertations - Archive

There has been an increased interest in the “craft” alcohol industry in recent years. Contrary to larger corporations that focus on standardizing their recipes for mass production, these small, independent businesses can experiment with ingredients and procedures to create unique and flavorful products. Beer and whiskey in particular have seen a surge in popularity, indicating the public may be interested in a deeper understanding of these beverages and their flavors on the chemical level. Brewing and distilling rely heavily on chemistry to perform the proper procedures to obtain the desired product, and to understand the interactions of the various ingredients. …

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Mechanistic Studies Of F420-Dependent Enzymes By Kinetic Analysis, Lindsay A. Davis Aug 2021

Mechanistic Studies Of F420-Dependent Enzymes By Kinetic Analysis, Lindsay A. Davis

Chemistry & Biochemistry Dissertations - Archive

The focus of this research is to elucidate the catalytic mechanism of F420-dependent enzymes using F420-dependent glucose-6-phosphate dehydrogenase (FGD) from Mycobacteria tuberculosis (Mtb) and F420H2:NADP+ Oxidoreductase (Fno) from Archaeoglobus fulgidis (A. fulgidis) as models. To investigate the mechanism of these enzymes, our group primarily utilizes UV-vis spectrophotometric techniques, in order to conduct steady-state and pre steady-state kinetic experiments. We also use fluorescence binding, and kinetic isotope effects methods in order to provide an in-depth understanding of these enzymes. This conglomeration of work will help to serve as model systems to enzymes who exhibit similar behavior, especially the understudied F420-dependent enzymes. …

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Supercritial Fluid Extraction - Supercritical Fluid Chromatography - Mass Spectrometry (Sfe-Sfc-Ms) Method Development For Online Extraction Of Complex Biological And Environmental Matrices, Blair Kristen Berger Aug 2021

Supercritial Fluid Extraction - Supercritical Fluid Chromatography - Mass Spectrometry (Sfe-Sfc-Ms) Method Development For Online Extraction Of Complex Biological And Environmental Matrices, Blair Kristen Berger

Chemistry & Biochemistry Dissertations - Archive

A systematic approach to the rapid development of hyphenated online methods for supercritical fluid extraction-supercritical fluid chromatography-mass spectrometry (SFE-SFC-MS) was established for the analysis of complex biological and environmental samples with limited sample sizes. Extensive sample preparation and cleanup is incompatible with small sample sizes. Hyphenated online extractions offer major advantages desirable where sample quantity is limited. By minimizing sample preparation and handling, online extractions provide higher throughput, and minimizes the opportunity for sample contamination or loss. However, hyphenated methods have been difficult to develop since each step has its own requirements, which has slowed penetration into many areas which …

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The Technical Study And Conservation Treatment Of A Silkscreen On Paper After Roy Lichtenstein, Colleen Watkins Aug 2021

The Technical Study And Conservation Treatment Of A Silkscreen On Paper After Roy Lichtenstein, Colleen Watkins

Art Conservation Master's Projects

Non-Objective I (After Mondrian) is a silkscreen on paper printed in four colors (red, yellow, blue, and black) made after Roy Lichtenstein’s 1964 painting of the same name. The print arrived at the Garman Art Conservation Department tightly rolled, with significant discoloration and mechanical damage resulting from rolled storage in an uncontrolled environment that disfigured the flat, matte fields of printing ink. The before-treatment state of the object hindered the overall aesthetic appreciation of the artwork as well as its purpose as a reproduction of the painting. Multi-modal imaging and analysis using Fourier Transform Infrared spectroscopy (FTIR), X-Ray Fluorescence spectroscopy …

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Synthesis And Study Of F-Block Complexes Containing Metal-Arene Interactions, Jesse Murillo Aug 2021

Synthesis And Study Of F-Block Complexes Containing Metal-Arene Interactions, Jesse Murillo

Open Access Theses & Dissertations

The f-block elements are of great interest due to the under explored nature of their chemical bonding interactions and their unique magnetic and electronic properties. For the 5f-orbital elements, such as uranium, the f-orbitals are more readily available for bonding than the contracted, core like, 4f-orbitals of the lanthanides. This makes uranium complexes informative probes into the nature of f-(p/d/f) bonding interactions. Recently, it has been shown that a growing subset of complexes possessing supported uranium-arene interactions have the capability to stabilize unusually low valent U(II) molecular species and support novel catalytic activity. In our laboratory, we have begun to …

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Synthesis Of Nanoparticles In A Silicate Matrix, Tatiana Alexandra Estrada-Mendoza Aug 2021

Synthesis Of Nanoparticles In A Silicate Matrix, Tatiana Alexandra Estrada-Mendoza

All Dissertations

Nanoparticle synthesis is the driving force behind research and development in nanotechnology. The development of more tailored nanoparticles for different uses is increasing the need for more efficient and cleaner synthetic methods. The use of sodium silicate matrix for the synthesis of various nanoparticles is a novel strategy requiring minimum laboratory set up. Exploratory studies that are presented and discussed here highlight the robust nature, versatility, and multifaceted role this matrix plays in the synthesis of nanoparticles. This dissertation focuses on the synthesis and properties of plasmonic hybrid nanoparticles and metal sulfide nanoparticles. The introductory chapter highlights the importance of …

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Stimuli Responsive Dye-Containing Peg-Pla Block Copolymer Micelles And Computationally Assisted Design Of A Stapled Peptide Bundle, Tyler L. Odom Aug 2021

Stimuli Responsive Dye-Containing Peg-Pla Block Copolymer Micelles And Computationally Assisted Design Of A Stapled Peptide Bundle, Tyler L. Odom

Graduate Theses/Dissertations

In this thesis, I report the preparation and characterization of dye-containing PEG-b-PLA block copolymer micelles and the computational design of a novel coiled-coil peptide bundle. The PEG-b-PLA micelles encapsulate hydrophobic molecules into their core and have strong potential as nanocontainers or delivery vesicles. In theory, these internalized molecules can be released upon exposure to mechanical forces that disrupt the micellar structures. This force-responsive nature is one of the inherent properties of micellar systems. However, there is a stark lack of research that utilize this property in applications. Along those lines, I have studied the behavior of …

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Characterization Of Lamellar Liquid Crystal Emulsifiers In Topical Creams Containing A Novel Solvent, Melinda Joanna Sutton Aug 2021

Characterization Of Lamellar Liquid Crystal Emulsifiers In Topical Creams Containing A Novel Solvent, Melinda Joanna Sutton

Graduate Theses/Dissertations

Diethylene glycol monoethyl ether (DEGEE) is a promising solvent component in topical cream formulations due to its superior solubilizing abilities with certain active pharmaceutical ingredients. One of the goals of this study is to characterize the effects of pH on the physical and chemical stabilities of topical cream formulations containing particularly high concentrations of DEGEE by characterizing a full topical pH profile of 3.5 – 9.0. The second goal is to evaluate the presence, amount, and characteristics of lyotropic liquid crystals (LLCs), molecularly structured in a lamellar phase, in a model cream emulsion utilizing polarized light microscopy (PLM). The presence …

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Exploring Electron-Sink Behaviors Of Molecular Assemblies, Yume Mai Aug 2021

Exploring Electron-Sink Behaviors Of Molecular Assemblies, Yume Mai

Boise State University Theses and Dissertations

Metal carbonyl clusters, such as the [Ni32C6(CO)36]6- anion, have been documented to display electron-sink phenomena. However, such large clusters suffer from inefficient yields due to their demanding and unreliable synthesis routes. To approach this obstacle, we investigated the electrochemical properties of Fe2(μ-PPh2)2(CO)6, an organometallic complex known to experience a reversible two-electron transfer process. In this work, we report a modular synthetic strategy for expanding the electron-sink capacity of molecular assemblies by installing Fe2(μ-PPh2)2(CO)6 redox mediators to arylisocyanide ligands. …

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Evaluation Of Dihedral Angle Twin Boundaries In Cu10 Wt%Zn Alloy Using Atomic Force Microscopy, Nataliya Starostina, Ann Mcguire, Richard Rowan Aug 2021

Evaluation Of Dihedral Angle Twin Boundaries In Cu10 Wt%Zn Alloy Using Atomic Force Microscopy, Nataliya Starostina, Ann Mcguire, Richard Rowan

Chemistry and Biochemistry

Atomic force microscopy (AFM) measurements of dihedral angles are conducted for the first time to characterize the ratio of the twin-boundary energy (γΤ) to the surface free energy (γS). In plane, twin morphology is measured with AFM, verified by scanning electron microscopy, optical microscopy, and found to be consistent. The chemical composition and homogeneity of annealed Cu10 wt%Zn sample are confirmed by energy-dispersive spectroscopy. AFM data indicate that the average depth and height of the grooves and peaks are 118 ± 45 and 158 ± 45 nm, respectively. Surface roughness parameters, Sq and …

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Synthesis Of Flagellin 22 As A Probe For Plant Signaling And Molecular Trafficking Towards Improved Crops, Edward Offei Aug 2021

Synthesis Of Flagellin 22 As A Probe For Plant Signaling And Molecular Trafficking Towards Improved Crops, Edward Offei

Electronic Theses and Dissertations

Plant signaling involves the transport of information within and between plant cells from receptors to effectors. Plants are affected by biotic and abiotic stress conditions like insect attack and extreme temperatures, respectively, which cause disease, the induction of senescence and the reduction of crop yield. To improve plant traits for feed, fiber, and energy applications, it is critical to understand the short- and long-range signaling mechanisms plants use to control growth, biomass composition, senescence and responses to environmental stresses. It is known that many plant signaling molecules have profound effects on plants, through mechanisms that remain largely obscure. A key …

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Investigations Of Elastin Recoil On Molecular And Macroscopic Levels., Nour Mohammad Jamhawi Aug 2021

Investigations Of Elastin Recoil On Molecular And Macroscopic Levels., Nour Mohammad Jamhawi

Electronic Theses and Dissertations

Elastin is one of the most hydrophobic proteins, and it is extremely flexible when hydrated. The driving force for recoil is the decrease in entropy of the protein and/or the hydrating solvent. This dissertation is a study of both mechanisms. Following an introduction (Chapter 1), Chapters 2 and 3 investigate the recoil mechanism on the molecular level in the hydrating solvent and in the protein, respectively. Chapter 4 examines macroscopic properties of recoil by thermomechanics. Conclusions are discussed in Chapter 5. Using double quantum NMR, the deuterated water ordering at the elastin surface was studied quantitatively as a function of …

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Synthesis, Characterization, And Catalytic Activity Of Functionalized Metal Bis(Thiosemicarbazones)., Caleb Aaron Calvary Aug 2021

Synthesis, Characterization, And Catalytic Activity Of Functionalized Metal Bis(Thiosemicarbazones)., Caleb Aaron Calvary

Electronic Theses and Dissertations

Bis-(thiosemicarbazones) are a class of ligands that have found a wide range of uses from electrocatalysts to medicinal and diagnostic reagents. These ligands contain a diimine backbone, N2S2 chelating core, and pendent amines. In order to further explore this class of ligands, the previously underreported transamination reaction, which exchanges one pendent amine group for another, was utilized to create several derivatives using aliphatic and aromatic amines. The transamination reaction is appealing alternative to making the desired thiosemicarbazide. Further appeals come from the fact that it is a one-pot reaction that gives highly pure products in good yields. …

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Mass Spectrometry Based Metabolomics And Lipidomics., Fang Yuan Aug 2021

Mass Spectrometry Based Metabolomics And Lipidomics., Fang Yuan

Electronic Theses and Dissertations

Metabolomics and lipidomics studies are important to understand living organisms at the molecular level. In this dissertation, I conducted various untargeted and targeted metabolomics and lipidomics studies using mass spectrometry based analytical platforms. Firstly, I investigated the androgen depletion effects on fecal metabolites in a mouse model of systemic lupus erythematosus and metabolite biomarkers for colorectal cancer using two-dimensional gas and liquid chromatography-mass spectrometry. Secondly, I investigated the relationship between gut microbiota-mediated resistance and susceptibility to malaria and the production of short-chain fatty acids using gas chromatography-mass spectrometry. Thirdly, I developed a high-throughput liquid chromatography-mass spectrometry method to profile long-chain …

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Electrochemical Characterization Of Surface-Immobilized Metal Nanostructures: Stability, Atomic Level Doping, Catalysis, And Sensing Applications., Badri Prasad Mainali Aug 2021

Electrochemical Characterization Of Surface-Immobilized Metal Nanostructures: Stability, Atomic Level Doping, Catalysis, And Sensing Applications., Badri Prasad Mainali

Electronic Theses and Dissertations

This dissertation has two main themes. The first theme involves voltammetric analysis of the stability of Au nanoparticles (NPs) under electrochemical and thermal treatment as a function of size, ligand stabilizer, and atomic composition. The second theme involves the use of Au NPs, electrophoretic deposition (EPD), and anodic stripping voltammetry (ASV) for electrochemical detection of analytes. The electrochemical size stability of 4.1, 15.1, and 50.3 nm average diameter Au NPs upon treatment with multiple electrochemical oxidation-reduction cycling in acidic electrolyte is monitored by observing changes in the peak oxidation potential (Ep) in ASV and the electrochemically measured surface …

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