Chemistry Commons^™

The Application Of Dispersion Staining And Infrared Microspectroscopy To Analyze Physical Evidence In Developing Countries, Thiti Mahacharoen

Dissertations, Theses, and Capstone Projects

In developing countries like Thailand and in remote forensic laboratories around the world, scientific investigations of crimes are limited by the shortage of trained personnel and financial resources. The premise of this research is that polarized light microscope and dispersion staining methods will be developed which allow investigators with limited training to analyze physical evidence at a minimal cost. This research identifies specific liquids for the analysis of trace evidence using the dispersion staining technique. The development of dispersion staining technique and identification of specific liquid will extend the application of forensic science to remote laboratories and in the field …

Metal Nanoparticles Immobilized On Basic Supports As Catalysts For Hydrogenation And Dehydrogenation Reactions Of Relevance To Cleaner Fossil Fuels And Alternative Sources Of Energy, Reena Rahi

Dissertations, Theses, and Capstone Projects

We developed a series of catalysts, composed of metal nanoparticles immobilized on basic supports for the hydrogenation of heteroaromatics of relevance to cleaner fossil fuels and biodiesel, and for the dehydrogenation of heteroaromatics of relevance to hydrogen storage in organic liquids. Our catalyst design involves nanostructured catalysts composed of metal particles immobilized on basic supports capable of ionic mechanism that may avoid catalyst poisoning and enhance catalytic activity.

We prepared a new catalyst composed of Pd nanoparticles immobilized on MgO by NaBH4 reduction of Na2PdCl4 in methanol in the presence of the support. TEM measurements revealed well-dispersed 1.7 nm Pd …

Synergism Between Airborne Singlet Oxygen And A Trisubstituted Olefin Sulfonate For The Inactivation Of Bacteria, Rajib Choudhury, Alexander Greer

Publications and Research

The reactivity of a trisubstituted alkene surfactant (8-methylnon-7-ene-1 sulfonate, 1) to airborne singlet oxygen in a solution containing E. coli was examined. Surfactant 1 was prepared by a Strecker-type reaction of 9-bromo-2-methylnon-2-ene with sodium sulfite. Submicellar concentrations of 1 were used that reacted with singlet oxygen by an “ene” reaction to yield two hydroperoxides (7-hydroperoxy-8-methylnon-8-ene-1 sulfonate and (E)-8-hydroperoxy-8-methylnon-6-ene-1 sulfonate) in a 4:1 ratio. Exchanging the H₂O solution for D₂O where the lifetime of solution-phase singlet oxygen increases by 20-fold led to an ∼2-fold increase in the yield of hydroperoxides pointing to surface activity …

Capping Amyloid Β‑Sheets Of The Tau-Amyloid Structure Vqivyk With Hexapeptides Designed To Arrest Growth. An Oniom And Density Functional Theory Study, Joshua A. Plumley, Jorge Ali-Torres, Gabor Pohl, J. J. Dannenberg

Publications and Research

We present ONIOM calculations using density functional theory (DFT) as the high and AM1 as the medium level that explore the abilities of different hexapeptide sequences to terminate the growth of a model for the tau-amyloid implicated in Alzheimer’s disease. We delineate and explore several design principles (H-bonding in the side chains, using antiparallel interactions on the growing edge of a parallel sheet, using all-D residues to form rippled interactions at the edge of the sheet, and replacing the H-bond donor N−H’s that inhibit further growth) that can be used individually and in combination to design such peptides that will …

Intramolecular Nitrogen Delivery For The Synthesis Of C-Glycosphingolipids. Application To The C-Glycoside Of The Immunostimulant Krn7000, Ahmad Sabri Altiti, David R. Mootoo

Publications and Research

The key reaction in this approach to C-glycosphingolipids is the stereoselective iodocyclization of a sugar-linked homoallylic carbonimidothioate. E and Z reaction substrates were assembled in a convergent fashion via an alkene metathesis strategy and exhibited the same alkene facial selectivity in the iodocyclization irrespective of alkene geometry, although the E alkene was found to be less reactive.

A Review Of Air–Ice Chemical And Physical Interactions (Aici): Liquids, Quasi-Liquids, And Solids In Snow, T. Bartels-Rausch, H-W Jacobi, T. F. Kahan, J. L. Thomas, E. S. Thomson, J. P. D. Abbatt, M. Ammann, J. R. Blackford, H. Bluhm, Chris Boxe, F. Domine, M. M. Frey, I. Gladich, M. I. Guzmán, D. Heger, Th. Huthwelker, P. Klán, W. F. Kuhs, M. H. Kuo, S. Maus, S. G. Moussa, V. F. Mcneill, J. T. Newberg, J. B. C. Pettersson, M. Roeselová, J. R. Sodeau

Publications and Research

Snow in the environment acts as a host to rich chemistry and provides a matrix for physical exchange of contaminants within the ecosystem. The goal of this review is to summarise the current state of knowledge of physical processes and chemical reactivity in surface snow with relevance to polar regions. It focuses on a description of impurities in distinct compartments present in surface snow, such as snow crystals, grain boundaries, crystal surfaces, and liquid parts. It emphasises the microscopic description of the ice surface and its link with the environment. Distinct differences between the disordered air–ice interface, often termed quasi-liquid …

Deconstructing A Plant Macromolecular Assembly: Chemical Architecture, Molecular Flexibility, And Mechanical Performance Of Natural And Engineered Potato Suberins, Olga Serra, Subhasish Chatterjee, Merce Figueras, Marisa Molinas, Ruth E. Stark

Publications and Research

Periderms present in plant barks are essential protective barriers to water diffusion, mechanical breakdown, and pathogenic invasion. They consist of densely packed layers of dead cells with cell walls that are embedded with suberin. Understanding the interplay of molecular structure, dynamics, and biomechanics in these cell wall-associated insoluble amorphous polymeric assemblies presents substantial investigative challenges. We report solid-state NMR coordinated with FT-IR and tensile strength measurements for periderms from native and wound-healing potatoes and from potatoes with genetically modified suberins. The analyses include the intact suberin aromatic; aliphatic polymer and cell-wall polysaccharides, previously reported soluble depolymerized transmethylation products, and undegraded …

Nickel-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Nucleophiles, Amruta Ajit Joshi

Dissertations, Theses, and Capstone Projects

In the first chapter, introduction of transition metal-catalyzed cross-coupling reactions has been given. These transition metal-catalyzed C-C bond forming reactions have been used extensively in organic synthesis. Among them, C(sp2)-C(sp2) bond forming reactions have been widely studied over decades. More recently, some reports have demonstrated the use of C(sp3) nucleophiles and electrophiles in cross-coupling reactions. However, use of secondary and tertiary alkyl nucleophiles has remained a challenge due to competitive β-hydride elimination and slow transmetallation of bulky secondary and tertiary alkyl organometallic nucleophiles.

In the second chapter, the first general nickel-catalyzed Negishi reaction for the cross-coupling of unactivated, acyclic secondary …

Conformational Features Of The Human U2-U6 Snrna Complex, Ravichandra Bachu

Dissertations, Theses, and Capstone Projects

The splicing of precursor messenger (pre-m) RNA, during which noncoding intervening sequences are excised and flanking coding regions ligated, is an integral reaction of gene expression. In eukaryotes, it is carried out by a dynamic RNA-protein complex called the spliceosome, in which five small nuclear (sn) RNA components are actively involved in recognition and chemical aspects of the process. A complex formed between U2 and U6 snRNAs is implicated in the chemistry of pre-mRNA splicing. The catalytic activity of the U2-U6 snRNA complex is dependent on the presence of Mg2+ ions, and the complex has been shown to have several …

Property Enhancements Of Dielectric Nanoparticles Via Surface Functionalization, Andrew Byro

Dissertations, Theses, and Capstone Projects

This thesis describes the surface modification of barium strontium titanate nanoparticles for use in polymer/ceramic composite thin film capacitors with resultant improved dielectric and film-making properties. Phosphonic acid-type ligands proved to be most effective for surface conjugation to the surface of the barium strontium titanate nanoparticles. Amine-terminated ligands proved to be effective at removing surface adsorbed water before being almost entirely removed during the sample washing stage. Carboxylic acid terminated ligands proved to adhere less well to the nanoparticle than the phosphonic acid, but resulted in thin films with a higher dielectric constant, which was more stable in the measured …

Fabrication And Assembly Of Patchy Particles With Uniform Patches, Zhenping He

Dissertations, Theses, and Capstone Projects

Patchy colloidal particles have been widely studied as the self-assembly building blocks to illustrate their potential for forming complex structures. The parameters affecting the final assembly structures include (i) patch size, shape, and number per particle, (ii) their relative positions, and (iii) the surface properties of the patch material. Recent computational studies have highlighted the impact of patch shape on assembly structure; however, there are only a limited number of methods that can provide control over patch shape and size. In this thesis, a template is introduced to the Glancing Angle Vapor Deposition method (GLAD) to create surface anisotropy on …

An Ethnobotanical, Ecological And Lc-Ms-Based Chemometric Investigation Of Phaleria Nisidai, A Traditional Adaptogen Containing Diterpene Esters From Palau, Micronesia, Daniel Kulakowski

Dissertations, Theses, and Capstone Projects

An ethnobotanical, ecological and LC-MS-based chemometric investigation of Phaleria nisidai, a traditional adaptogen containing diterpene esters from Palau, Micronesia

Palau is a country with a rich heritage of traditional medicine still being practiced. One of the most popular and respected remedies in Palau is a tea made from fresh leaves of Phaleria nisidai Kaneh. (Thymelaeaceae). Interviews conducted to determine the use of this plant revealed that it is employed non-specifically to treat a variety of general health concerns. Its use as a prophylactic to keep away sickness, as a 'system cleaner', as well as for strength and energy indicate …

Development Of Mesoporous Silicas, Responsive Polymer Microgels, And Related Nanocomposites, Yingyu Li

Dissertations, Theses, and Capstone Projects

This dissertation covers research on polymer-templated nanoporous materials and functional soft materials, and it consists of four major parts. The first part is on introduction. The next part (Chapters 2-3) describes the research work on the synthesis of silicas with spherical mesopores. Chapter 2 is focused on the synthesis of large-pore FDU-12 silicas at room temperature by using surfactants with large hydrophilic blocks and relatively small hydrophobic blocks (such as Pluronic F108 (EO132PO50EO132)) as the template. Chapter 3 discusses an interesting mesopore structure, which is the hollow silica nanosphere (HSN). The single-micelle-templating strategy provides a general approach for the synthesis …

Organic Pi-Stacking Semiconducting Material: Design, Synthesis And The Analysis Of Structure And Properties, Bin Wang

Dissertations, Theses, and Capstone Projects

Organic semiconducting materials have been under intensive investigation in the recent decades for potential applications in various electronic or optoelectronic devices such as light emitting diodes, photovoltaic cells and field effect transistors. Compared to inorganic counterparts, organic charge transport materials are attractive for their abilities of forming thin-films, large area manufacturing, compatibility with flexible substrate, light weight and potential low fabrication cost. The charge transport property of the organic active layer is one of the key factors to the electronic or optoelectronic performance of devices. Research projects presented in this thesis focused on improving charge carrier mobility of organic charge …

Chemistry Of 6-Monobrominated Indigo, Mbi, Hiroko Ajiki

Dissertations, Theses, and Capstone Projects

6-monobrominated indigo, MBI, is a component of a historically important and the most expensive colorant, Tyrian Purple.

The colorant is remarkably stable under the sun, in the air and after extensive washing with water. The color is still vivid after thousands of years. Even though it has such a high stability, MBI and Tyrian Purple have color changes from purple to blue upon temperature changes. This color change has been known for long to certain people, but the mechanism of the color change was unknown.

Tyrian Purple also has recently attracted interests for applications towards semiconducting material due to its …

Intelligent Nano/Microgels For Cell Scaffold And Drug Delivery System, Jing Shen

Dissertations, Theses, and Capstone Projects

Stimulus-responsive polymer microgels swell and shrink reversibly upon exposure to various environmental stimuli such as change in pH, temperature, ionic strength or magnetic fields. Therefore, they become ideal candidates for biomaterial applications. For this work, we focus on the several intelligent microgels and their application on two areas: the cell scaffold and the drug delivery system.

As for the cell scaffold, it can be realized by colloidal supra-structure microgels, which constructed by the thermo-driven gelation of the colloidal dispersion of poly(N-isopropylacrylamide-co-acrylamide) poly(NIPAM-co-AAm) microgels (Chapter 3). Such microgels exhibit a reversible and continuous volume transition in water with volume phase transition …

Cyclic Phosphonium Ionic Liquids, Sharon I. Lall-Ramnarine, Joshua A. Mukhlall, James F. Wishart, Robert R. Engel, Alicia R. Romeo, Masao Gohdo, Sharon Ramati, Marc B. Berman, Sophia N. Suarez

Publications and Research

Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners.

Chemistry Students’ Attitudes About Peer-Led Team Learning Workshops: Comparison To The Six Critical Components, A.E. Dreyfuss, Janet Liou-Mark, Leo Gafney

Publications and Research

While tracking students’ performance and perseverance is important to determine the effect of the incorporation of workshops in courses, little has been published on students’ attitudes toward workshops: How do students feel about PLTL workshops? One method of examining this question is through a questionnaire developed by Gafney. This paper will present the results of a three-semester study using this questionnaire on how students view workshop in their introductory chemistry courses.

Biobased Amphiphiles As Molecular Gelators, Nneoma C. Ezeude

Dissertations and Theses

No abstract provided.

The Study Of The Degradation Rates Of The Hexabromocyclododecane Isomers With Polysulfides At 25 Oc And Ph 9 In 80% Water / 20% Methanol, John H. Wilson

Dissertations and Theses

No abstract provided.

Students’ Attitudes About Peer-Led Team Learning Workshops In General Chemistry: A Critical Incident Study, A.E. Dreyfuss, Janet Liou-Mark

Publications and Research

How would students respond to open-ended questions regarding their experiences with PLTL workshops? This paper will present the results of a two-semester qualitative study on how students view workshop in their introductory chemistry courses, using Brookfield’s (1995) Critical Incident Questionnaire (CIQ). The five questions probe what stands out in the affirmative and negative, using key words: engaged, distanced, affirmed, puzzled or confused, and surprising. Collecting key moments from students in workshop, after several weeks of meeting, allow a grounded sense of how students view the workshop experience.

Peer Leaders’ Views On A General Chemistry Workshop Program, A.E. Dreyfuss, Janet Liou-Mark

Publications and Research

How do Peer Leaders feel about their role organizationally? What motivates them to serve? Peer Leaders are the heartbeat of the PLTL instructional model. To improve any PLTL program, feedback from Peer Leaders is necessary and beneficial. Their experiences, ideas, and honest critiques will assist in shaping the program to meet its ultimate goal: To ensure all students are engaged in their learning process through an active community setting.

Chimeric Rhinoviruses Displaying Mper Epitopes Elicit Anti-Hiv Neutralizing Responses, Guohua Yi, Mauro Lapelosa, Rachel Bradley, Thomas M. Mariano, Denise Elsasser Dietz, Scott Hughes, Terri Wrin, Chris Petropoulos, Emilio Gallicchio, Ronald M. Levy, Eddy Arnold, Gail Ferstandig Arnold

Publications and Research

Background: The development of an effective AIDS vaccine has been a formidable task, but remains a critical necessity. The well conserved membrane-proximal external region (MPER) of the HIV-1 gp41 glycoprotein is one of the crucial targets for AIDS vaccine development, as it has the necessary attribute of being able to elicit antibodies capable of neutralizing diverse isolates of HIV.

Methodology/Principle Findings: Guided by X-ray crystallography, molecular modeling, combinatorial chemistry, and powerful selection techniques, we designed and produced six combinatorial libraries of chimeric human rhinoviruses (HRV) displaying the MPER epitopes corresponding to mAbs 2F5, 4E10, and/or Z13e1, connected to an immunogenic …

Winsor & Newton Original Handbooks: Asurface-Enhanced Raman Scattering (Sers) Andraman Spectral Database Of Dyes From Modernwatercolor Pigments, Federica Pozzi, John R. Lombardi, Marco Leona

Publications and Research

Background

Winsor & Newton Ltd. has been one of the main fine art products providers since its establishment in 1832, being responsible for the manufacture of a wide assortment of materials ranging from oils and pigments to brushes and papers. All the items produced over the years have been indexed in a comprehensive historical archive. Original Winsor & Newton handbooks are a powerful resource which can offer insight into the world of artists’ materials, and knowledge of artists’ choices through the identification of substances employed to obtain particular colors. Scientific analyses of various kinds have been carried out on Winsor …

Uv-Visible Microscope Spectrophotometric Polarization And Dichroism With Increased Discrimination Power In Forensic Analysis, Dale Kevin Purcell

All Open Access Legacy Dissertations and Capstone Projects

Microanalysis of transfer (Trace) evidence is the application of a microscope and microscopical techniques for the collection, observation, documentation, examination, identification, and discrimination of micrometer sized particles or domains. Microscope spectrophotometry is the union of microscopy and spectroscopy for microanalysis. Analytical microspectroscopy is the science of studying the emission, reflection, transmission, and absorption of electromagnetic radiation to determine the structure or chemical composition of microscopic-size materials. Microscope spectrophotometry instrument designs have evolved from monochromatic illumination which transmitted through the microscope and sample and then is detected by a photometer detector (photomultiplier tube) to systems in which broad-band (white light) illumination …

Reality Of Chemistry Is Far From Stereotypes, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Chemist Breaks With The Usual Stereotypes, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Energy Of The Quasi-Free Electron In Repulsive Atomic And Molecular Fluids, Yevgeniy Lushtak

Dissertations, Theses, and Capstone Projects

The ability to predict accurately the energy V₀(ρ) of the quasi-free electron along the entire density (ρ) range of a supercritical fluid has applications in determining the ideal thermodynamic conditions for chemical reactions involving charged species. The previously established field ionization method of extracting V₀(ρ) from the fluid density dependent shift Δ(ρ) in the ionization energy of a dopant molecule has led to the discovery of a novel effect on V₀(ρ) occurring near the critical isotherm of the fluid. Unfortunately this method has limitations in determining V₀(ρ) in fluids with low critical …

Supercharging: An Investigation Into The Effects Of External Amino Acid Residue Charge On The Solubility And Internal Electric Character Of Bound Ligands In A Heme-Binding De Novo-Designed Protein, Cooper French

Dissertations and Theses

De novo protein design offers many interesting prospects both as a means to better understand natural protein dynamics and as a potential resource in biomedical and industrial applications. In this work I describe the modification of a simple, well-characterized heme-binding protein by altering side chain residue identities on the hydrophilic surface of the protein to produce variants with a range of net external charges. These charge modifications had a significant impact on nearly every measurable character of the protein. This work establishes the hard limits of supercharging within our experimental protein scaffold system, demonstrating that excessive positive charge increased the …

Inhibition Of Pokeweed Antiviral Protein (Pap) By Turnip Mosaic Virus Genome-Linked Protein (Vpg), Artem V. Domashevskiy, Hiroshi Miyoshi, Dixie J. Goss

Publications and Research

Pokeweed antiviral protein (PAP) from Phytolacca americana is a ribosome-inactivating protein (RIP) and an RNA N-glycosidase that removes specific purine residues from the sarcin/ricin loop of large rRNA, arresting protein synthesis at the translocation step. PAP is also a cap-binding protein and is a potent antiviral agent against many plant, animal, and human viruses. To elucidate the mechanism of RNA depurination, and to understand how PAP recognizes and targets various RNAs, the interactions between PAP and turnip mosaic virus genomelinked protein (VPg) were investigated. VPg can function as a cap analog in cap-independent translation and potentially target PAP to uncapped …