Thesis (M.S.)--Biomedical Engineering, Georgia Institute of Technology, 2003. / John Oshinski, Committee Member; Paul Benkeser, Committee Member; Xiaoping Hu, Committee Chair. Includes bibliographical references (leaves 45-47).

Thesis (M.S.)--Brigham Young University. Dept. of Computer Science, 2003. / Includes bibliographical references (p. 120-130).

Thesis (M.S.)--Florida State University, 2002. / Advisor: Dr. Frank B. Gross, Florida State University, FAMU-FSU College of Engineering, Dept. of Electrical and Computer Engineering. Title and description from dissertation home page (viewed Oct. 2, 2003). Includes bibliographical references.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004. / Vachtsevanos, George J., Committee Chair; Dorrity, J. Lewis, Committee Member; Egerstedt, Magnus, Committee Member; Heck-Ferri, Bonnie S., Committee Co-Chair; Williams, Douglas B., Committee Member; Yezzi, Anthony J., Committee Member. Includes bibliography.

Thesis (M. Sc.)--York University, 2000. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 107-111). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ56168.

Lanthanide-doped upconversion nanoparticles (UCNPs) are perceived as promising novel near-infrared (NIR) bioimaging agents characterised by high contrast and high penetration depth. However, the interactions between charged UCNPs and mammalian cells have not been thoroughly studied and the corresponding intracellular uptake pathways remain unclear. Herein, my research work involved the use of hydrothermal method and ligand exchange approach to prepare UCNP-PVP, UCNP-PEI, and UCNP-PAA. These polymer-coated UCNPs demonstrated good water dispersibility, the similar size distribution as well as similar upconversion luminescence efficiency. However, the positively charged UCNP-PEI evinced greatly enhanced cellular uptake in comparison with its neutral or negative counterparts, as revealed by cellular uptake studies. Meanwhile, it was discovered that cationic UCNP-PEI could be effectively internalized mainly through the clathrin endocytic machanism. This study is the first report on the endocytic mechanism of positively charged lanthanide-doped UCNPs. Furthermore, it allows us to control the UCNP-cell interactions by tuning surface properties. Glioblastoma multiforme (GBM) is the most common and malignant form of primary brain tumors in humans. Small molecule MRI contrast agents are used for GBM diagnosis and preoperative tumor margin delineation. However, the conventional gadolinium-based contrast agents have several disadvantages, such as a relatively low T1 relaxivity, short circulation half lives and the absence of tumor targeting efficiency. Multimodality imaging probes provide a better solution to clearly delineate the localization of glioblastoma. My research work also involved the development of multimodal nanoprobes for targeted glioblastoma imaging. Two targeted paramagnetic/fluorescence nanoprobes were designed and synthesized, UCNP-Gd-RGD and AuNP-Dy680-Gd-RGD. UCNP-Gd-RGD was prepared through PEGylation, Gd3+DOTA conjugation and RGD labeling of PEI-coated UCNP-based nanoprobe core (UCNP-NH2). It adopted the cubic NaYF4 phase, had an average size of 36 nm by TEM, and possessed a relatively intense upconversion luminescence of Er3+ and Tm3+. It also exhibited improved colloidal stability and reduced cytotoxicity compared with UCNP-NH2, and a higher T1 relaxivity than Gd3+DOTA. AuNP-Dy680-Gd-RGD was synthesized through bioconjugation of amine-modified AuNP-based nanoprobe core (AuNPPEG- NH2) by a NIR dye (Dy680), Gd3+DOTA and RGD peptide. It demonstrated a size of 3–6 nm by TEM, relatively strong NIR fluorescence centered at 708 nm, longterm physiological stability, and an enhanced T1 relaxivity compared with Gd3+DOTA. Targeting abilities of both UCNP-Gd-RGD and AuNP-Dy680-Gd-RGD towards overexpressed integrin αvβ3 receptors on U87MG cell surface was confirmed by their enhanced cellular uptake visualized by confocal microscopy imaging and quantified by ICP-MS, where their corresponding control nanoprobes were used for comparison. Furthermore, targeted imaging capabilities of UCNP-Gd-RGD and AuNP-Dy680-Gd- RGD towards subcutaneous U87MG tumors were verified by in vivo and ex vivo upconversion fluorescence imaging studies and by in vivo and ex vivo NIR fluorescence imaging and in vivo MR imaging studies, respectively. These two synthesized targeted nanoprobes, with surface-bounded cyclic RGD peptide and numerous T1 contrast enhancing molecules, are applicable in targeted MR imaging glioblastoma and delineating the tumor boundary. In addition, UCNP-Gd-RGD favors the upconversion luminescence with NIR-to-visible nature, while AuNPDy680- Gd-RGD possesses NIR-to-NIR fluorescence, and both lead to their potential applications in fluorescence-guided surgical resection of gliomas. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

The objective of this study was to enable the removal of developer depletion and diffusion effects (i.e., adjacency effects from noisy photographic images, thus, providing a potential for improvement in the reliability of restored object and aerial image estimates. The investigation was based on the use of a previously formulated image resortation model which characterized the exposure, latent image and development interactions of the photographic process in terms of statistical estimation theory. This study addressed the application and appropriate modification of the formulated model in the removal of adjacency effects from noisy images of selected line targets. Literature pertaining to the initial observations of adjacency effects, their recognition as a nonlinear chemical development effect and the pertinent models (forward) used to predict their effects was reviewed. This was followed with a review of the statistical restoration (inverse) model and its comparison to previously derived forward models. X-ray quanta exposures were then used to obtain noisy photographic images, free of optical scattering effects, for the purpose of empirically determining a chemical spread function to characterize chemical adjacency effects. Photographic images were obtained that contained lines of 0.010, 0.100 and 1.000 mm widths to enable comparison between the magnitude of the chemical spread function and the Eberhard effect. A segmented polynomial (cubic spline function) approach was used to calculate the chemical spread function. Separate light quanta exposures were used to obtain gross grain density sensitometric curves and noisy line images. The covering power relationship between mass of developed silver and diffuse density was empirically derived for Panatomic-X film processed without agitation in D-76 developer (diluted 1:1). Emperical verification of the statistical restoration model was achieved. Chemical adjacency effects were successfully removed from noisy line images using an appropriately scaled version of the statistical restoration model. The spatial frequency content of the noisy line images was approximately 1, 10, 15, 20, 25 and 40 cycles/mm. The proportionality factor, used to scale the chemical spread function required in the restoration model, was found to be equivalent to the ratio of the empirically derived chemical spread function and a magnitude estimate of the Eberhard effect. The maximum diffuse density correction for edge effects was found to be 0.14, or approximately 11.1% of the gross grain density level, 1.20. Similar diffuse density corrections for fine line images were found to range between 0.14 and 0.36, or approximately 11.1% to 28.3% of the gross grain density level associated with a specific line element.

No description available.

No description available.