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Full-Text Articles in Physics
Enhancement And Evaluation Of Proton Pencil Beam Spot Placement Algorithms, Mahboob Ur Rehman
Enhancement And Evaluation Of Proton Pencil Beam Spot Placement Algorithms, Mahboob Ur Rehman
Electronic Theses and Dissertations, 2020-
Intensity modulated proton therapy (IMPT) in the form of pencil beam scanning (PBS) has shown improvement in treatment plan quality as compared to conventional proton and photon-based radiotherapy techniques. However, in IMPT maintaining a sharp lateral dose falloff is crucial for sparing organs at risk (OARs), especially when they are in close proximity to the target volume. The most common approach to improve lateral dose falloff is through the use of physical beam shaping devices, such as brass apertures or collimator-based systems. This work has shown that IMPT can be further improved by implementation of advanced spot placement techniques by …
Biophysical Analysis Of The Structure And Aggregation Of Amyloid Beta Peptide, Faisal Abedin
Biophysical Analysis Of The Structure And Aggregation Of Amyloid Beta Peptide, Faisal Abedin
Electronic Theses and Dissertations, 2020-
Alzheimer's disease (AD) is the major cause of dementia and is characterized by neuronal death and brain atrophy. The amyloid ß (Aß) peptide is tightly associated with neuronal dysfunction during AD, but the molecular mechanism underlying the neurotoxic effect of Aß is poorly understood. Extracellular fibrillar deposits (plaques) of Aß were initially believed to be the cause of AD, but currently there is overwhelming evidence that the prefibrillar Aß oligomers are the major toxic entities. Structural characterization of Aß oligomers and fibrils is important for understanding the structural features determining the toxic potency of the peptide. This project has studied …
Structure Of Unmodified And Pyroglutamylated Amyloid Beta Peptide In Lipid Membranes, Rowan Hassan
Structure Of Unmodified And Pyroglutamylated Amyloid Beta Peptide In Lipid Membranes, Rowan Hassan
Honors Undergraduate Theses
Alzheimer's Disease (AD) is a devastating neurodegenerative disease that is characterized by brain atrophy, neuronal and synaptic loss, cognitive decline, trouble handling activities of daily life, and ultimately leads to death. Worldwide, at least 30 million people suffer from AD, with 5.8 million suffering in the US alone. Despite extensive basic and clinical research, the underlying molecular mechanisms behind AD remain largely unknown. There are four FDA-approved compounds are used for alleviating symptoms but have no curative potency. The first potentially disease-modifying AD drug, aducanumb, was approved by FDA in June 2021. The main histopathological traits of AD are the …
Dual Beam Frequency Comb Ftir Spectroscopy, Connor Kelly
Dual Beam Frequency Comb Ftir Spectroscopy, Connor Kelly
Electronic Theses and Dissertations, 2020-
A visible and Infrared (IR) range dual beam frequency comb Fourier transform spectrometer was developed. Using dual mode-locked Ti:Sapphire lasers a comb-interferogram was generated in the visible range. This spectrum was calculated and used to measure the transmittance of a Nd-doped crystal. The system was further developed to generate an IR interferogram by Difference Frequency Generation (DFG) using a Gallium Selenide (GaSe) crystal placed in the mode-locked pump beam. Numerical work was done to calculate the expected DFG spectrum confirming the necessary IR range can be reached. This has been conducted in support of an IR holographic spectroscopic microscopy spatial …
Structure Difference And Implication To Assembly Morphology Control Of Rous Sarcoma Virus Capsid Protein, John Hastings
Structure Difference And Implication To Assembly Morphology Control Of Rous Sarcoma Virus Capsid Protein, John Hastings
Honors Undergraduate Theses
Rous Sarcoma Virus (RSV) is an avian retrovirus with an enclosing capsid protein (CA) shell. RSV CA is studied due to its similar molecular structure to other retrovirus capsid proteins such as Human Immunodeficiency Virus (HIV). In this project, turbidity assay is used to track the assembly process of RSV CA, while solid state nuclear magnetic resonance (ssNMR) is used to probe the CA structure at a site specific level and investigate the morphology of the spherical structure of the I190V mutated strain of RSV CA. The I190V mutant is a naturally occurring mutation and is able to form into …
Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera
Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera
Honors Undergraduate Theses
In this thesis, we investigate biological molecules on a micron scale in the ultraviolet spectral region through the non-destructive confocal absorption microscopy. The setup involves a combination of confocal microscope with a UV light excitation beam to measure the optical absorption spectra with spatial resolution of 1.4 μm in the lateral and 3.6 μm in the axial direction. Confocal absorption microscopy has the benefits of requiring no labels and only low light intensity for excitation while providing a strong signal from the contrast generated by the attenuation of propagating light due to absorption. This enables spatially resolved measurements of single …