Physical Sciences and Mathematics Commons^™

Synthesis, Characterization And Application Of Sugar-Based Low Molecular Weight Gelators, Ifeanyi Simeon Okafor

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) are an interesting class of compound that have gained considerable attention especially because of their potential applications for soft biomaterials. Carbohydrate based low molecular weight hydrogelators and organogelators are able to selfassemble and form ordered supramolecular structures, which are useful for exploring biomedical applications. The resulting gelators are responsive to external stimuli because of the weak noncovalent intermolecular forces and interaction that influences self-assembly. Stimuli-responsive supramolecular organogels with interesting properties in response to external environmental stimuli have gained considerable attention due to their applications in biomaterials, sensors and for drug delivery.

One of the major …

Lignin Contribution To The Global Carbon Pool: Investigating The Abiotic Modification Of Lignin By Reactive Oxygen Species, Derek Charles Waggoner

Chemistry & Biochemistry Theses & Dissertations

Evidence suggests that reactive oxygen species (ROS), largely generated through photochemical processes, are important in transforming the chemical composition of the large pool of terrestrially-derived dissolved organic matter (DOM) exported from land to water annually. However, due to the challenges inherent in isolating the effects of individual ROS on DOM composition, the role of ROS in the photochemical alteration of DOM remains poorly characterized. The main focus of the studies within this dissertation aim to more thoroughly characterize the alterations to lignin, used as an analog for terrestrial DOM, resulting from reactions with ROS.

To investigate the possibility that the …

Observations Of Greenhouse Gas Isotopologues With Ace-Fts And Waccm, Eric Michael Buzan

Chemistry & Biochemistry Theses & Dissertations

Increases in greenhouse gas concentrations in the atmosphere are the major driver of climate change. Quantifying the sources and sinks of these gases is a major focus of research. Measuring isotopologues, or molecules that differ in isotopic composition, is one useful way of constraining the budget of a molecule as they are highly sensitive to different sources and sinks. However, measurements above the surface have been restricted to a few locations and have only reached the lower stratosphere. Satellite-based remote sensing can achieve nearly global measurement coverage, but so far no satellites have measured isotopologues.

Presented here are measurements of …

Characterization Of 3-Ester And 3-Carbamate Derivatives Of N-Acetyl-D-Glucosamine And Their Use In Controlled Drug Delivery, Consuelo Garcia

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) are a class of compounds which reversibly form a network that traps solvents to form gels. Gelation by LMWGs is driven solely by non-covalent interactions such as hydrogen bonding, π - π stacking, and hydrophobic interactions. LMWGs can be designed such that the gel-sol and sol-gel transitions happen as a response to a specific stimulus. These stimulus responsive gels or “smart” gels can be used in a wide variety of applications including tissue regeneration, biosensing, and controlled drug delivery.

Among the different types of compounds that are LMWGs, carbohydrate based systems are especially interesting. Carbohydrates …

Alicyclic And Aromatic Carboxylic Acids In Soil Organic Matter: An Investigation Of Potential Origin And Association With Plutonium Using Advanced Analytical Techniques, Nicole Didonato

Chemistry & Biochemistry Theses & Dissertations

Carboxylic acids are a defining component of soil organic matter, responsible for many of the physical and chemical properties, including metal-organic matter interactions, which govern its role as an important constituent of soils. However, there is a shortage of detailed molecular level information regarding orientation and structural arrangement of carboxylic acids within soil organic matter. This dissertation utilizes electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) as well as solid-state and multi-dimensional nuclear magnetic resonance (NMR) to investigate the molecular formula composition within several organic matter sources and the primary structures that feature carboxylic acids. Soil organic matter …