Digital Commons Network^™

Electron Paramagnetic Resonance Imaging And Probes, Hanan B. Elajaili

Electronic Theses and Dissertations

EPR imaging at low frequency is an important method to measure in vivo physiology. Because native paramagnetic species exist at low concentrations in living systems, exogenous paramagnetic species are needed for in vivo EPR. Selection of the appropriate EPR probe allows the experimenter to obtain information about the environment of the imaged probe and its spatial distribution. Relaxation times for several nitroxide radicals were studied with the aim of understanding the relaxation mechanisms, which provides criteria for design of suitable in vivo imaging probes.

Amino-substituted trityl radicals have the potential to monitor pH in vivo, and the suitability for this …

Passivation And Functionalization Of Conjugated Polymer Nanoparticles With Head Group Modified Phospholipids And Proteins, Prakash Kandel

All Dissertations

Conjugated polymer nanoparticles (CPNs) possess important characteristics such as high fluorescence brightness, reasonable photostability, and non-toxicity. These properties allow the use of CPNs in fluorescence based cellular and biological applications including cellular labeling, imaging, biosensing, and single particle tracking. To realize the broad applications of CPNs, it is required that CPNs possess functionality to conjugate a recognition moiety and maintain colloidal stability in biological media. In the following Dissertation, we have prepared functionalized CPNs by surface passivation with head group- functionalized poly (ethylene glycol) lipids and proteins. We studied the colloidal stability of CPNs in biological media and investigated their …

Fluorescence Photoactivation Based On 2-Nitrobenzyl Derivatives, Subramani Swaminathan

Open Access Dissertations

Fluorescence microscopy offers a non-invasive way to image biological species in real time. The phenomenon of diffraction, however, restricts the resolution of the conventional fluorescent microscopes to submicrometer dimensions in both the horizontal and vertical directions. This limitation can be overcome with the aid of photoactivatable fluorophores. Photoactivatable fluorophores switch from a nonemissive state to an emissive one under irradiation at an activation wavelength and then emit light in form of fluorescence upon illumination at an excitation wavelength. Such a concatenation of activation and excitation events translates into the possibility to switch fluorescence on within a defined region of space …

The Born Approximation, Multiple Scattering, And The Butterfly Algorithm, Alejandro F. Martinez

Theses and Dissertations - UTB/UTPA

Radar works by focusing a beam of light and seeing how long it takes to reflect. To see a large region the beam is pointed in different directions. The focus of the beam depends on the size of the antenna (called an aperture). Synthetic aperture radar (SAR) works by moving the antenna through some region of space. A fundamental assumption in SAR is that waves only bounce once. Several imaging algorithms have been designed using that assumption. The scattering process can be described by iterations of a badly behaving integral. Recently a method for efficiently evaluating these types of integrals …

The Treachery Of Imaging, Charlie C. Campbell

Theses

"The Treachery of Imaging" is a conceptual exploration of digital media's translational nature, a recognition of its ubiquity in our visual culture, and its fallibility. This work is an experiment in process; the dissection of a workflow for the purposeful obfuscation and destruction of digital imaging technology in opposition to its commonly held status as a scientifically accurate measurement tool; or as Paul Gsell referred to it, "an unimpeachable mechanical witness."

Through reflection, reference, reiteration, repetition, and the construction of algorithms "Treachery" is a process-oriented body of visual work, a documentation of this process, presentation, and context created in the …

Nitroxide Radicals For Low Frequency Electron Paramagnetic Resonance Imaging (Epri), Joshua R. Biller

Electronic Theses and Dissertations

Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties such as spin lattice relaxation times, spin packet linewidths, and nuclear hyperfine splitting. Initial measurements of relaxation times for six low molecular weight nitroxides at X-band stimulated further measurement at frequencies between 250 MHz and 34 GHz. The impact of tumbling was studied with perdeuterated 2,2,6,6-tetramethyl-4-piperidinyl-1-oxyl (PDT) in five solvents with viscosities resulting in tumbling correlation times, τ_R, between 4 and 50 ps. A set of three ¹⁴N/¹⁵N pairs of nitroxides in water was selected such that τ_R varied between …

Integration Of Instrumentation And Processing Software Of A Laser Speckle Contrast Imaging System, Jacob James Carrick

Dissertations, Master's Theses and Master's Reports - Open

Laser speckle contrast imaging (LSCI) has the potential to be a powerful tool in medicine, but more research in the field is required so it can be used properly. To help in the progression of Michigan Tech's research in the field, a graphical user interface (GUI) was designed in Matlab to control the instrumentation of the experiments as well as process the raw speckle images into contrast images while they are being acquired. The design of the system was successful and is currently being used by Michigan Tech's Biomedical Engineering department. This thesis describes the development of the LSCI GUI …

Diffraction-Based Techniques For High Contrast X-Ray Imaging, Lubna Naseem Peerzada

Legacy Theses & Dissertations (2009 - 2024)

Two X-ray diffraction based techniques for high contrast were explored to improve contrast in radiology: diffraction enhanced imaging (DEI) and coherent scatter imaging.

A Spatiotemporal Model For Repeated Imaging Data, Brandon George

All ETDs from UAB

Longitudinal imaging studies have increased in popularity as clinical researchers seek to investigate how phenomena within the body change over time. Analysis of data from these studies is complicated by correlation between repeated measures over time and different locations in the body. To address this problem we propose the use of a linear model with a separable parametric correlation structure. This model considers spatial and temporal correlation independently and incorporates the correlation using parametric functions that have the potential to be much more efficient than an unstructured approach. Our model also has the ability to control for time- and space-varying …

Quantum Optical Metrology, Sensing And Imaging, Kebei Jiang

LSU Doctoral Dissertations

In this dissertation we begin with a brief introduction to quantum optics concentrating on the topics of the noise of quantum optical states, quantum estimation theory, quantum interferometry and the atom-field interaction. This background is necessary for understanding the discussions in later chapters. In particular, quantum interferometry, which is optical interferometry when the light source is a quantum mechanical state, plays a central role in this dissertation. In Chapter 2 we discuss the phase estimation sensitivity of quantum metrology when photon loss is present. In Chapter 3 we extend the discussion to include the phase fluctuation of the system caused …

Tomographic Imaging Of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy (Tdlas), Avishek Guha

LSU Doctoral Dissertations

This work concentrates on enabling the usage of a specific variant of tunable diode laser absorption spectroscopy (abbr. TDLAS) for tomogaphically reconstructing spatially varying temperature and concentrations of gases with as few reconstruction artifacts as possible. The specific variant of TDLAS used here is known as wavelength modulation with second harmonic detection (abbr. WMS-2f) which uses the wavelength dependent absorbance information of two different spectroscopic transitions to determine temperature and concentration values. Traditionally, WMS-2f has generally been applied to domains where temperature although unknown, was spatially largely invariant while concentration was constant and known to a reasonable approximation (_x0006_+/- 10% …