ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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Silicon incorporation into Ge1-ySny yields a new class of Ge1-x-ySixSny (y>x) ternary alloys using reactions between Ge3H8, Si4H10, and SnD4. These materials contain small amounts of Si (x=0.05-0.08) and Sn contents of y=0.1-0.15. Photoluminescence studies indicate an intensity enhancement relative to materials with lower Sn contents (y=0.05-0.09). These materials may serve as thermally robust alternatives to Ge1-ySny for mid-infrared (IR) optoelectronic applications.
An extension of the above work is the discovery of a new class of Ge-like Group III-V-IV hybrids with compositions Ga(As1–xPx)Ge3 (x=0.01-0.90) and (GaP)yGe5–2y related to Ge1-x-ySixSny in structure and properties. These materials are prepared by chemical vapor deposition of reactive Ga-hydrides with P(GeH3)3 and As(GeH3)3 custom precursors as the sources of P, As, and Ge incorporating isolated GaAs and GaP donor-acceptor pairs into diamond-like Ge-based structures. Photoluminescence studies reveal bandgaps in the near-IR and large bowing of the optical behavior relative to linear interpolation of the III-V and Ge end members. Similar materials in the Al-Sb-B-P system are also prepared and characterized. The common theme of the above topics is the design and fabrication of new optoelectronic materials that can be fully compatible with Si-based technologies for expanding the optoelectronic capabilities of Ge into the mid-IR and beyond through compositional tuning of the diamond lattice.
FRDA is a progressive neurodegenerative disease caused by insufficient expression of frataxin (FXN). FXN is instrumental in the assembly of iron-sulfur clusters, which in turn are critical for the functioning of the ETC enzyme complexes. Therapeutic agents which, in addition to being antioxidants also increase FXN, can be good drugs to counter FRDA. In Chapter 2, the synthesis of phenothiazine analogues are described. Moreover, their efficacy as antioxidants and their ability to increase FXN are described. Finally, the synthesis of a reduced salt form of one analogue and its ability to cross the blood brain barrier (BBB) in mouse models of the disease is also described.
In Chapter 3, to discover potent neuroprotective drugs, a pair of regioisomeric benzoquinone analogues has been synthesized. The compounds were tested for their efficacy as antioxidants. Additionally, two pyrimidinol based redox cores were analyzed electrochemically to enable a better understanding of the mechanism of action of the multifunctional radical quencher (MRQ) class of antioxidants.
Herein, a new cost-effective and scalable synthesis of various types of nanocrystalline zeolites based on geopolymer chemistry is presented. The study includes the synthesis of highly crystalline discrete nanorods of a CAN zeolite framework structure that had not been achieved hitherto, the exploration of the Na−Al−Si−H2O kinetic phase diagram of hydrogels that gives SOD, CAN and FAU nanocrystalline zeolites, and the discovery of a unique formation mechanism of highly crystalline nanostructured FAU zeolite with intermediate gel products that possess an unprecedented uniform distribution of elements. This study demonstrated the possibility of using high-concentration hydrogels for the synthesis of nanocrystalline zeolites of additional framework structures.
Moreover, a comprehensive study on nanostructured FAU zeolites ion-exchanged with Ag+, Zn2+, Cu2+ and Fe2+ for antibacterial applications is presented, which comprises metal ion release kinetics, antibacterial properties, and cytotoxicity. For the first time, superior metal ion release performance was confirmed for the nanostructured zeolites compared to their micron-sized counterparts. The metal ion-exchanged FAU nanostructured zeolites were established as new effective antibacterial materials featuring their unique physiochemical, antibacterial, and cytotoxic properties.