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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 …
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 …