Physical Sciences and Mathematics Commons^™

Structure And Thermodynamics Of Polyglutamine Peptides And Amyloid Fibrils Via Metadynamics And Molecular Dynamics Simulations, Riley Workman

Electronic Theses and Dissertations

Aggregation of polyglutamine (polyQ)-rich polypeptides in neurons is a marker for nine neurodegenerative diseases. The molecular process responsible for the formation of polyQ fibrils is not well understood and represents a growing area of study. To enable development of treatments that could interfere with aggregation of polyQ peptides, it is crucial to understand the molecular mechanisms by which polyQ peptides aggregate into fibrils. Many experimental techniques have been employed to probe polyQ aggregation, however, observations from these studies have not lead to a unified understanding of the properties of these systems, instead yielding competing, fragmented theories of polyQ aggregation. This …

Singlet Oxygen Oxidation Of Guanine, 9-Methylguanine And Guanine-Cytosine Base Pair: Dynamics And Kinetics Revealed By Parallel Gas- And Solution-Phase Experiments And Computations, Wenchao Lu

Dissertations, Theses, and Capstone Projects

Singlet oxygen (¹O₂) oxidatively generated damage of DNA gives rise to mutagenesis, carcinogenesis, and cellular death. Guanine is the most susceptible DNA target of ¹O₂. The related process has been studied over three decades but the mechanism has remained elusive. My thesis research has focused on reaction mechanism, dynamics and kinetics of ¹O₂ oxidation of guanine, 9-methylguanine and guanine-cytosine base pair, from the gas-phase bare ions, through hydrated clusters, to aqueous solution. Various techniques have been adapted in the work, including ¹O₂ generation and detection, guided-ion beam tandem mass …

Computational And Analytical Modelling Of Droplet-Macroion Interactions, Myong In Oh

Electronic Thesis and Dissertation Repository

Charged droplets involving macromolecules undergo distinct disintegration mechanisms and shape deformations as a consequence of droplet-macroion interactions. Three general classes of droplet-macroion interactions that have been identified in the Consta group are: contiguous extrusion of a linear macroion from a droplet, "pearl-necklace" droplet conformations, and "star"-shaped droplets. This dissertation probes in a systematic manner the onset and various outcomes of macroion-droplet interactions, using atomistic molecular dynamics and realistic examples of solvent and macromolecules.

When the charge-squared-to-volume ratio of a droplet is below but near a threshold value, certain flexible macromolecules, such as poly(ethylene glycol), extrude from a droplet, induced by …

3d Momentum Imaging Spectroscopy Probing Of Strong-Field Molecular And Surface Dynamics, Lin Fan

Wayne State University Dissertations

Electron-ion coincidence measurements in combination with 3-dimensional (3D) momentum imaging can provide comprehensive 3D-momentum information to unravel multichannel photoionization/dissociation processes, and thus is an effective tool to investigate atomic/molecular dynamics. A camera-based 3D coincidence momentum imaging system and the velocity mapping imaging (VMI) based machine were introduced in Chapter 2. Studies of strong field dissociative single and double ionization of relatively large molecules camphor and 2-phenylethyl-N, N-dimethylamine (PENNA) were carried out and illustrated in Chapter 3. We demonstrated the main products of double ionization of PENNA were singlet diradicals. In Chapter 4, a novel angle resolved-photoemission spectroscopy based on VMI …