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Synthesis, Structural Characterization And Chromatographic Evaluation Of Silica Hydride-Based Perfluorinated Stationary Phase, Harshada Suyog Natekar

Master's Theses

Silica hydride based stationary phases have demonstrated unique selectivity and specificity for small sized polar molecules. The weakly hydrophobic nature of silica hydride is thought to be the key reason for its remarkable retention capabilities. Traditional stationary phases bonded with fluorine moieties have also exhibited enhanced retention of small polar molecules. In this research, a perfluorinated silica hydride stationary phase was synthesized by hydrosilation and silanization procedures. Chromatographic characterization of the newly packed column was carried out by a large number of retention studies. The separation capabilities of the column were evaluated in both the aqueous normal-phase (ANP) and reversed-phase …

Photochemistry Of A Series Of Weakly Coupled Dinuclear Ruthenium(Ii) Complexes, Latisha Michelle Puckett

Graduate Theses and Dissertations

An improved synthetic method was developed for symmetric ruthenium(II) polypyridine complexes with the form L2Ru(diphen)RuL2. The scope of the reaction was investigated in regards to the ligands, bridging ligands, and starting materials. Several ligands were successful in the synthesis, including 2,2’-bipyridine (bpy), 4,4’-dimethyl-2,2’-dipyridyl (dmb), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (dpphen), and 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen). Ligands that did not react to form symmetric dimeric complexes were 2,2’-bipyrazine, bpz, and 2,2’-bipyrimidine, bpm.

Dpp, 2,3-bis(2-pyridyl)-pyrazine, effectively replaced diphen as the bridging ligand to produce (phen)2Ru(dpp)Ru(phen)24+. However, replacing the [Ru(CO)2Cl2]n with Ru(DMSO)4Cl2 did not prove successful. The newly developed synthesis was also applied to the synthesis of …

Mining Public Databases For Discovery Of Structure And Function Within The Hotdog-Fold Thioesterase And Had Phosphatase Enzyme Families, Sarah Toews Keating

Chemistry and Chemical Biology ETDs

For my doctoral work, I have developed strategies to mine public databases for data that can be used to infer structural and functional information for the hotdog-fold and HADSF superfamilies. For the hotdog-fold superfamily, I used curated and automatically applied annotations of structure, taxonomic lineage, function, and subfamily membership from the UniProtKB, gene context and taxonomic information from the NCBI, and the results of several in-depth explorations of subfamily/function and structural class membership. Based on the distribution of the aforementioned annotations mapped onto a sequence similarity network (SSN), I applied structural assignments to sequences and/or specific function/subfamily assignments to ~143,000 …

Metal-Ligand Cooperative Catalysis And Methods For Metal Removal From Organic Transformations, John-Paul J. Bow

Electronic Thesis and Dissertation Repository

Organometallic catalysis has revolutionized the synthesis of complex organic molecules. Methods for C-C, C-X and C-H bond formation and cleavage are exploited throughout the areas of fine chemicals synthesis, with major applications for pharmaceuticals. This situation raises duel challenges: 1) high-performance catalysts for environmentally and economically sustainable synthesis and 2) efficient methods of catalyst (i.e. metal) removal must be identified. This work tackles both of these areas. The highly tunable cooperative P^R₂N^R'₂ ligands have been implemented for the first time for catalytic organic transformations. I show that [Ru(Cp)(P^tBu₂N^Bn₂)(MeCN)][PF_{6 …}

Morphology-Property Relationship For Binary Organic Thin Films, Alyssa Lynn Griffin

Master's Theses

Organic thin films can be readily mass-produced through solution-based fabrication methods including ink-printing and solution-casting because their light weight, flexibility, and inexpensive sources. Their applications range from organic field-effect transistors (OFET), organic solar cells (OSC), to organic light emitting diodes (OLEDs). Compared with pure component films, binary organic thin films (BOTF) allows for novel characteristics and specialized features to handle more demanding tasks. Due to the complex intermolecular interactions in BOTF, various microscopic phases with different morphological and electronic properties may be formed and this information is difficult to extract through conventional bulk measurements.

Organic thin films can be readily …

Synthesis Of A Ditopic Verdazyl Ligand And Investigation Of Its Coordination To Transition Metals, Erik Charles Johnson

Master's Theses

The goal of this research project was to prepare a self-assembled grid complex with a ditopic bis-verdazyl ligand and nickel(II) ions. A verdazyl is a relatively stable type of organic free radical in which the unpaired electron is delocalized over four nitrogen atoms. The ditopic verdazyl ligand was synthesized in six steps, and its coordination to metal ions, in particular Ni2+, was investigated. The hypothesized complex of the ligand with Ni2+ is potentially functional as a molecular magnet due to the free radical nature of the ligand; hence, the complex could be useful for information storage. The ligand was definitively …

Metals On Titania/Hopg As Models For Heterogeneous Catalysts, Randima Piyumalie Galhenage

Theses and Dissertations

The work done in this thesis is mainly focused on understanding the nanoscale morphology and activity of model heterogeneous catalysts. In order to do this we design and prepare model catalytic surfaces in ultrahigh vacuum (UHV) and study these surfaces using electron and ion based microscopies and spectroscopies. The nucleation, growth and chemical activity of mono and bimetallic clusters on TiO₂(110) were investigated in order to understand how activity is influenced by cluster sizes, interactions with the oxide support and surface compositions of the bimetallic clusters. For example, Au-based and Pt-based bimetallic clusters such as Co-Au, Co-Pt, and …

Impact Of Ocean Acidification On Aphotic Biogeochemical Production Of Reactive Oxygen Species, Sarah Ann Murphy

Theses and Dissertations

Reactive oxygen species (ROS) are critical to global maintenance of the global organic carbon cycle, sulfur cycle, oxygen cycle, and transition metal cycles. The primary source of ROS is commonly considered to be photolysis or photochemically driven reactions, however ROS also exist in aphotic zones. A geochemical mechanism for the same in dark environments based on the tidally driven, episodic movement of anoxic groundwaters through oxidized, Fe(III) rich sediments is shown. Predictive models were developed based on in vitro experiments and tested using sediment samples collected from a saline tidal creek in the estuary at Murrell’s Inlet, South Carolina. These …

Facile Method For Large Scale Alignment Of One Dimensional Nanoparticles And Its Biomedical Application, Sheng Feng

Theses and Dissertations

Topographical cues can profoundly affect cellular behaviors. This thesis investigate how to utilize the topographical cues generated by two techniques, flow assembly and electrospinning, to regulate cellular behaviors.

First of all, a facile and robust method to align one-dimensional (1D) nanoparticles (NPs) in large scale has been developed. Using flow assembly, representative rod-like nanoparticles, including tobacco mosaic virus (TMV), gold nanorods and bacteriophage M13, have been aligned inside capillaries by controlling flow rate and substrate surface properties. The properties of 1D NPs, such as stiffness and aspect ratio, play a critical role in the alignment. Furthermore, these hierarchically organized structures …

Designing Instruction For Recovering Alcoholics: The Role Of Executive Function And Levels Of Guidance In Learning From Visually Complex Simulations, Jeffrey Gutkin

Dissertations, Theses, and Capstone Projects

The present study examines the design of visually complex science simulations. Building upon an earlier study by Homer and Plass (2014), the current research determines under which circumstances adult learners, and alcoholics in recovery, would perform better from while learning with different levels of guidance. It was predicted that alcoholic adults in recovery would have impaired Executive Function (EF) as compared to controls selected from the general population and that EF would affect learning. An experiment investigated whether levels of EF predict learning from simulations that offered higher or lower levels of instructional guidance. Participants were 76 adults, half of …

Restoration Of Headwater And Coastal Fens In The Lake Superior Basin Of Upper Michigan, James A. Bess

Dissertations, Master's Theses and Master's Reports - Open

In 2009, research projects were initiated at Michigan Technological University to develop restoration techniques for headwater fens and coastal wetlands in the southern Lake Superior Basin in Michigan’s Upper Peninsula. The primary focus of these was to quantify the efficacy of using locally collected seeds as a technique for wetland restoration. Two primary sites were selected, the Sleeper Lake Fen complex in Luce County and the Portage Waterway-Keweenaw Bay region of Lake Superior in Baraga and Houghton Counties. At the Sleeper Lake site, a combination of heavy machinery, seeding and mulch application was used to restore a 1.6 km ditch …

Development Of An Isotopic Approach For Detailing Heparin Sequences, Qing Guo

Doctoral Dissertations

Heparin/heparin sulfates are carbohydrate polyionic polymers that participate in a host of critically important biological processes such as blood anticoagulation, pathogen infection, cell differentiation, growth, migration and inflammation, to mention a few. A century has passed since heparin’s initial discovery with a fair understanding of its overall composition. Unfortunately, there has been no structural work at the detailed chemical level that might support a synthetic effort. In this study, I utilize a chemical derivatization strategy (dual permethylation) that imparts isotopic structural specificity, which can be followed by step-wise disassembly in an ion trap mass spectrometer, (MSn). A set of analytical …

Formal Synthesis Of Cj-12,954 And Cj-13,014 Using Zinc-Mediated Tandem Chain Extension-Aldol Reaction And Synthesis And Investigation Of Diastereoselectivity Of Hydroxy-Cyclopropyl Peptide Isosteres, Yashoda Naga Deepthi Bhogadhi

Doctoral Dissertations

A formal synthesis of the natural products CJ-12,954 and CJ-13,014 was successfully accomplished using the zinc-mediated tandem chain extension-aldol reaction methodology. This chemistry was performed on a chiral β-keto imide synthesized using a DCC coupling reaction. The diastereoselectivity of the aldol reaction was controlled by an Evans chiral auxiliary. Comparison between the reported and experimental spectral data for the spiroketals confirmed the structural assignment.

The diastereoselectivity of the homologation-cyclization-rearrangement-lactonization reaction of β-keto imide derived from phenyl carbamate-protected proline was studied. Tetra-n-butylammonium fluoride-mediated rearrangement of trimethylsilyl cyclopropanol demonstrated the role of chiral auxiliary and the amino acid stereocenter in controlling the …

Single Chain Technology: Toward The Controlled Synthesis Of Polymer Nanostructures, Christopher Kenneth Lyon

Doctoral Dissertations

A technique for fabricating advanced polymer nanostructures enjoying recent popularity is the collapse or folding of single polymer chains in highly dilute solution mediated by intramolecular cross-linking. We term the resultant structures single-chain nanoparticles (SCNP). This technique has proven particularly valuable in the synthesis of nanomaterials on the order of 5 – 20 nm. Many different types of covalent and non-covalent chemistries have been used to this end.

This dissertation investigates the use of so-called single-chain technology to synthesize nanoparticles using modular techniques that allow for easy incorporation of functionality or special structural or characteristic features. Specifically, the synthesis of …

Solute Partitioning In Elastin-Like Polypeptides: A Foundation For Drug Delivery Applications, Eric Helm

ETD Archive

No abstract provided.

Characterization Of Cold Drawn Poly L Lactic Acid By Raman Spectroscopy And Raman Hyperspectral Imaging, Ramya Sudha Muttavarapu

ETD Archive

Artificial modulation of bone growth and repair processes is an important area of current research. Studies have established that the micro mechanical and bulk physical properties of a polymer implant influence its performance behavior and degradation patterns in the body. One important parameter for the class of polymers known as polylactides is the degree of crystalline character. Hence, studying the bulk and micro crystalline composition of an important polymer implant, Poly-L-Lactic acid is the objective of this study. Poly-L-Lactic acid has elastic properties that can be tailored to resemble natural bone and its reaction to mechanical stress. Varying degrees of …

Science For Visually Impaired Students And Accessible Technology, Lydia M. Moreland

Theses, Dissertations and Capstones

Blind and visually impaired students need appropriate methods and accessible technology in order to compete and advance in learning the science concepts. The study investigated the attitudes, perceptions, and knowledge of assistive technology used by science teachers of the visually impaired from a Mid-Atlantic state and how they are incorporated in the classroom. The participant response gives notice to what forms of assistive technology are used in frequency, and the training and comfort level to use the assistive technology. The open responses stated themes of teachers needing more training in visual impairment college programs to use assistive technology to increase …

Click Chemistry Protein Immobilization, James P. Kraley

Williams Honors College, Honors Research Projects

The main purpose of the first part in the lab was to try and determine a way to measure the moles of dye per mole of protein in order to detect an azide tag on a recombinantly produced azide-IFN-γ protein. This was done by using click chemistry to bind the azide tagged protein to a dye and then measured the azide tag efficiency. The main purpose of the second part of the project was to make a protein, SDF-1α, and tag it with an azide group. This was completed via processes of expression, isolation, and purification of the protein. From …

The Implementation Of Two Cooperative Learning Structures, Rally Coach And Teams-Games-Tournaments, In High School Chemistry Courses, Joanna Miketinas Stewart

LSU Master's Theses

To combat the obstacles that students experience in chemistry, two cooperative learning strategies, Rally Coach and Teams-Games-Tournaments, were implemented in five chemistry courses at East Ascension High School. Rally Coach called for two students to work as a pair and peer tutor to successfully complete practice problems for each lesson. Teams-Games-Tournaments required students to work in groups of four to complete practice problems and compete for team points as a review. Every student experienced both learning strategies. A comparison was made to see which cooperative learning strategy better helped student performance, including comparisons of effects on different student demographics and …

Experiences Teaching Stoichiometry To Students In Grades 10 And 11, Cynthia Denise Bridges

Walden Dissertations and Doctoral Studies

Many students have problems learning stoichiometry, a complex mathematical chemistry concept used to determine how much product will be produced or formed from a given quantity of reactants. The problem addressed in this study was teachers' lack of understanding of how to teach stoichiometry in a Midwestern urban school district. The conceptual framework of the study was based upon constructivist theory. A qualitative narrative approach was used to obtain the perceptions of 5 high school chemistry instructors related to their experiences, successful or unsuccessful, in teaching stoichiometry to students in Grades 10 and 11. Data were gathered through face-to-face interviews, …

Investigating The Synthesis Of Heterocycles Via Gold Catalyzed Cyclizations And Cyclo-Dehydrating Reactions, Katherine L. Childers

Undergraduate Honors Thesis Projects

The goal of this project was to study novel synthetic procedures for heterocycles. This was achieved through a two-part investigation. In the first part, a variety of conditions for the gold catalyzed cyclization of allenes were studied. This work was focused on the lesser studied intermolecular reactions of allenes. A variety of allenes were synthesized, and then reacted with 1,3-dipoles and a gold catalyst. These reactions were determined to be unsuccessful through the analysis of nuclear magnetic resonance spectroscopy data. In the second part of this study, the synthesis of 1,3,4-oxadiazoles was investigated. Several cited procedures were examined to determine …

Physicochemical And Structural Analysis Of Polymers As Putative Drugs, Meghan L. Thompson

Theses and Dissertations

Sulfated low molecular weight lignins (LMWLs) have shown good activity as anticoagulants by allosterically inhibiting thrombin, as well as promising agents for treating emphysema through inhibition of elastolysis, oxidation, and inflammation. Sulfated LMWLs are chemo-enzymatically synthesized from starting monomers caffeic, ferulic, and sinapic acid into sulfated dehydropolymers known as CDS, FDS, and SDS. To further the LMWLs’ development as drugs, their structural composition and physicochemical characteristics were defined in this work. The molecular weight distribution profile of the sulfated LMWLs from size exclusion chromatography performed on a high pressure liquid chromatography system (SEC-HPLC) changed from bimodal when no surfactant is …

The Effectiveness Of Online Homework Tutorials As Compared To Pen And Paper Tutorials, Molly Shuman

LSU Master's Theses

The purpose of this study was to determine if students learn more from completing web based homework (WBHW) compared to completing homework by traditional means with pen and paper. Determining the efficacy of WBHW is important because many schools are being pressured to implement technology in the classroom. To determine the effectiveness of WBHW, student normalized learning gains were calculated from pre and post-test scores for 62 students. Learning gains were then compared when students completed WBHW, traditional homework, or did not complete homework at all, over four units in a high school chemistry class. No difference in learning gains …

The Implementation Of Judicial Policy In Crime Laboratories : An Examination Of The Impact Of Melendez-Diaz V. Massachusetts, Catherine L. Bonventre

Legacy Theses & Dissertations (2009 - 2024)

In Melendez-Diaz v. Massachusetts (2009), the United States Supreme Court held that the Sixth Amendment right to confront adverse witnesses includes the right to confront forensic analysts who produce affidavits certifying the results of forensic examinations used against defendants at trial. The decision thus invalidated the practice of substituting forensic laboratory reports for live testimony in criminal trials. Melendez-Diaz was a divided decision in which four dissenting Justices predicted onerous practical consequences for the practice of forensic science in the United States. Through a web-based survey and semi-structured interviews, this dissertation explored the practical impact of the decision on crime …

Conditions For Deterministic Limits Of Markov Jump Processes : The Kurtz Theorem In Chemistry, Ada Anna Sedova

Legacy Theses & Dissertations (2009 - 2024)

A theorem by Kurtz on convergence of Markov jump processes is presented as it relates

Characterization Of Noncovalent Complexes Of Polyelectrolytes By Mass Spectrometry, Anthony J. Marino

Williams Honors College, Honors Research Projects

Various ions of poly-L-lysine and polystyrene sulfonic acid were successfully observed first within a matrix-assisted laser desorption/ionization mass spectrometer and subsequently in an electrospray ionization mass spectrometer. The successful ionization of these polymers allowed for studies to be performed on the noncovalent interactions between the two. Noncovalent interactions were effectively studied on both instruments, but further quantified using tandem mass spectrometry found within the MALDI system and ion-mobility mass spectrometry found within the electrospray ionization system. As a result of employing the use of ion-mobility, various different stoichiometries and charges of polyelectrolyte complexes could be distinguished.

Photogenerated O-Azaxylylenes: Mechanistic Studies And Synthetic Applications, William Cole Cronk

Electronic Theses and Dissertations

This research sets out to build upon excited state o-azaxylylene cycloaddition. The mechanism behind the excitation and cycloaddition process of photogenerated o-azaxylylenes was determined experimentally. Time-correlated single-photon counting, steady-state spectroscopy, triplet quenching experiments, and quantum yield studies provided evidence suggesting that excited state intramolecular proton transfer is followed by intersystem crossing and stepwise addition to the tethered unsaturated pendant.

In keeping with the principles of diversity oriented synthesis, a modular approach was taken to gain access to a diverse array of N,O,S-Polyheterocycles which were modified postphotochemically via Suzuki coupling to yield fused biaryls. Cycloaddition products, outfitted with halogens …

A Continuous Process Towards The Synthesis Of Quinolones, Stevara N. Clinton

Theses and Dissertations

Abstract

The development of quinolones is described from the first quinolone to the latest fluoroquinolones. Quinolones have generated considerable interest since their discovery because of their antibacterial capabilities. Analogs incorporating the 4-quinolone ring system comprise a largely expanding group of synthetic compounds. The development of antibacterial resistance has created the need for an efficient synthesis of quinolones that can be easily adapted toward the assembly of quinolone based antibacterial drugs.

There are several reported approaches to the 4-quinolone ring system. Many of these methods use expensive starting materials, require the removal of high boiling solvents, or use high temperature conditions …

Gold Nanomolecules : Developing Synthetic Protocols, Characterization And Investigation Of Ligand Effects On Structure And Properties, Praneeth Reddy Nimmala

Electronic Theses and Dissertations

The term "Nano" in chemistry refers to particles/molecules in the size range 1 to 100 nm. Gold nanoparticles were used in ancient times in making decorative glass as they produce vibrant, size dependent, colors upon interaction with light. Gold is a preferred choice of metal for the synthesis of nanoparticles mainly due to its inertness to atmospheric conditions and most chemicals. Gold thiolate nanomolecules, which is the primary focus of this dissertation research, are chemical molecules with a fixed number of gold atoms and organo-thiolate ligands. They are of the form Aux(SR)y and possess molecule-like properties as a result of …

A Gas Chromatographic/Mass Spectral Analysis Of Aromatic Medicinal Plants From Yemen, Bhuwan Khatri Chhetri

Theses

Yemen is a small country located in the southwestern part of the Arabian Peninsula. Yemen’s coastal lowlands, eastern plateau and deserts give it a diverse topography, which along with climatic factors make it opulent in flora. Despite the introduction of western medicinal system during the middle of the twentieth century, herbal medicine still plays an important role in Yemen. However, little has been done on the study of the aromatic medicinal plants that have been used through ages to cure and heal diseases. To this end, in collaboration with Deparment of Pharmacognosy, Faculty of Pharmacy, Sana’a University, Yemen the essential …