Physical Sciences and Mathematics Commons^™

Investigating The Thermal Stability And Cation Ordering In Layered Cathode Lixmo2 (X ≤ 1; M = Co, Mn, Ni) Materials For Li-Ion Rechargeable Batteries And Studying The Ferroelectric Properties Of Linbo3 Nanoparticles, Debasish Mohanty

University of New Orleans Theses and Dissertations

In recent years, transition metal oxides have drawn extensive attention because of their wide application in electronic, memory, battery, informatics, and optoelectronics devices. In this dissertation, we have studied two different types of oxide materials which are technologically important: LiMO 2 (M = Co, Mn, Ni), has served as cathode materials in the rechargeable battery, and LiNbO3, has wide application in ferroelectric devices such as electronics, non-volatile memories, and thin film capacitors. LiMO2 was synthesized and characterized to understand the correlation between capacity fading and thermal stability relating to the microstructures. Our results showed that delithiated (charged) LiCoO2, forms a …

Synthesis And Antifungal Evaluation Of Spirostane Saponins, Sunil Upadhyay

University of New Orleans Theses and Dissertations

Methods for the preparation of novel antifungal saponins have been investigated in

order to further explore their medicinal utility and provide the opportunity to synthesize

their derivatives.

Through this work, several partially protected stereoisomers of Cholestane,

Androstane and Spirostane have been prepared which could be used for the synthesis of

various saponin derivatives in order to discover novel saponin based antifungal agent.

Various mono and disaccharide derivatives of these steroids have been synthesized and

evaluated for their antifungal activity against four pathogenic fungal strains. Among the

various derivatives maltose derivatives were found to have the best antifungal activity.

However there …

Synthesis And Biological Evaluation Of Aeruginosin Based Compounds And Self-Assembly Of Glucosamine Based Compounds, Navneet Goyal

University of New Orleans Theses and Dissertations

Aeruginosins are a family of marine natural products containing mostly non-proteogenic amino acids. These compounds contain a common 2-carboxy-6-hydroxy-octaindole (Choi) rigid bicyclic structure. Many aeruginosins are inhibitors for enzymes involved in the blood coagulation cascade, such as thrombin and Factor VIIa. In order to understand the structure activity relationship (SAR) of the aeruginosins and to discover novel anticoagulants with potentially improved inhibitory and pharmacokinetic properties, in the first part of my thesis I have discussed, synthesis of a series of novel analogs of aeruginosin 298-A, in which the Choi will be replaced with L-proline and oxygenated Choi analogs, and the …

Synthesis And Applications Of Luminescent Quantum Dots In Bioassays, Venkata Ramana Kethineedi

University of New Orleans Theses and Dissertations

Luminescent quantum dot (QD) based probes have gained significance in the last decade for optical imaging of cells, tissues and in bioassays as alternatives to conventional organic fluorophores. The main objective of my PhD dissertation was to develop luminescent quantum dot based bioassays for real time monitoring of enzyme activity and simultaneous detection of several biomarkers. The quantum dot based bioassays developed will be potential tools in identification and diagnosis of several ailments that interfere with normal living conditions of human beings.

In Chapter 2 new liposome encapsulated quantum dot based fluorescence resonance energy transfer (FRET) probes have been fabricated …

Development Of A Novel Electron-Transfer Secondary Reaction Matrix, Characterization Of The Site–Specificity Of Novel Bilin-Lyase, And Fundulus Grandis Protein Expression Investigation Using Mass Spectrometry, Mohamed N. Boutaghou

University of New Orleans Theses and Dissertations

Reported in this dissertation are the results of investigations performed at the New Orleans Center for Mass Spectrometry at the University of New Orleans. The projects that are detailed in the coming pages take on a variety of subjects, but a common thread is that each employs matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to solve a problem. Fundamental aspects of MALDI in-plume ionization are implicated in the introduction of a newly developed electron-transfer secondary ionization matrix. The remaining projects are related to the ever expanding field of proteomics. Mass spectrometry was used to investigate the site specificity of a newly …

Self-Assemblies Driven By The Hydrophobic Effect, Haiying Gan

University of New Orleans Theses and Dissertations

Water is a simple molecule but is an essential part of life. One key aspect of the properties of water is the hydrophobic effect, and whilst there is an appreciation of this phenomenon at the macro-scale (raindrops falling off leaves) and the micro-scale (the structure of cellular systems), a complete understanding at the molecular level still eludes science. Addressing this issue, our studies involve synthetic supramolecular compounds that assemble in water via the hydrophobic effect.

First of all, a novel water-soluble deep-cavity cavitand was synthesized. It possesses four endo methyl groups on top rim of the cavitand, eight water-solubilizing carboxylic …

Water In Protein Cavities: Free Energy, Entropy, Enthalpy, And Its Influences On Protein Structure And Flexibility, Hongtao Yu

University of New Orleans Theses and Dissertations

Complexes of the antibiotics novobiocin and clorobiocin with DNA gyrase are illustrative of the importance of bound water to binding thermodynamics. Mutants resistantto novobiocin as well as those with a decreased affinity for novobiocin over clorobiocinboth involve a less favorable entropy of binding, which more than compensates for amore favorable enthalpy, and additional water molecules at the proteinligandinterface.Free energy, enthalpy, and entropy for these water molecules were calculated by thermodynamicintegration computer simulations. The calculations show that addition of thewater molecules is entropically unfavorable, with values that are comparable to the measuredentropy differences. The free energies and entropies correlate with the …

Towards The Synthesis Of Magnesidin, Subramanya Pingali

University of New Orleans Theses and Dissertations

Magnesidin is a magnesium chelate of the 3-hexanoyl and 3-octanoyl tetramic acid derivatives isolated from Psuedomonas magensiorubra. Its activity against grampositive bacteria was found to be a specific target for Gingivitis, a dental plaque.Although the synthesis of magnesidin has been reported earlier, it was not reproducible. The highly polar nature and it’s ability to exhibit tautomerization makes their chemical behavior complex and difficult to predict its structure. A variety of reactions and an in depth understanding of the chemical structure is necessary to attain the synthesis of these compounds. This dissertation focuses on addressing the attempts towards the synthesis …

Synthesis Of Chiral Intermediates By Deritivization Of Monosaccharides, Sanjeeva Dodlapati

University of New Orleans Theses and Dissertations

Conformationally constrained bicyclic amino acids are invaluable in the synthesis of natural products and peptidomimetics. Aeruginosins contain novel bicyclic amino acid, 2--‐carboxy--‐6--‐hydroxyl octahydrindole (Choi) as the core structure. Aeruginosins are tetra peptide serine protease inhibitors isolated from marine sponges and cyanobacterial water blooms. Rigid bicyclic amino acid(Choi)is an essential core structure, which strongly influences biological activity of aeruginosin family members. Aeruginosins showed promising inhibitory activity against thrombin, trypsin, and factor VIIa. Thrombin and factor VIIa play a major role in blood clotting cascade; excessive coagulation leads to thrombosis and other cardiovascular diseases. Several research groups have reported a number of …

Synthesis And Characterization Of Nanostructures In Porous Anodic Aluminum Oxide Templates, Jin-Hee Lim

University of New Orleans Theses and Dissertations

In this study, template-based methods are used for the fabrication of various nanostructures such as nandots, nanorods, nanowires, nanotubes, and core-shell structures. Porous alumina membranes were employed as templates and metal nanostructures were synthesized in the templates by electrodeposition. By using lithography techniques, controlled patterned nanostructures were also fabricated on alumina templates. The magnetic properties of the various metal nanostructures were investigated. The pore size, interpore distance, and pore geometry highly affect magnetic properties of nanostructures grown in the templates. Hexagonally ordered porous alumina templates can be fabricated by two-step anodization. The pore diameters and interpore distances were readily controlled …

Topochemical Manipulation Of Layered Perovskites, Elisha A. Josepha

University of New Orleans Theses and Dissertations

Topochemical strategies, techniques that allow one to effectively manipulate the structures of nonmolecular solids once a crystal lattice is established, are effective in the low temperature (< 500 °C) modification of solid state structures, allowing the preparation of nonmolecular compounds not accessible by standard synthetic routes. Some of the techniques, ion exchange, intercalation/deintercalation, have proven to be excellent synthetic methods for preserving specific frameworks. The combination of these techniques can allow one to create a multistep approach that can be used to design new compounds with interesting properties.

As an expansion to the field of topotactic reactions, a multistep approach was developed towards the synthesis of the new compounds (A xM0.5Cly)LaNb2O7 (where A = Rb, Cs; M = Fe, Ni; x ≈ 1.5;y ≈ 1) at temperatures below 400oC. The first reaction step involved the ion exchange of the host materials (ALaNb2O7, A = Rb, Cs) to form the products M0.5LaNb2O7 (where M = Fe, Ni), a structure open to further …

Tuning The Thermal Relaxation Of Transition-Metal Ferrite Nanoparticles Through Their Intrinsic Magnetocrystalline Anisotropy, Jose M. Vargas, Abhishek Srivastava, Amin Yourdkhani, Luis Zaldivar, Gabriel Caruntu, Leonard Spinu

Chemistry Faculty Publications

Monodispersed ferrite nanoparticles of Fe3O4, MnFe2O4, and CoFe2O4 (near to 10 nm), were synthesized by organometallic synthesis, showing the same homogeneous chemical, morphological, and crystalline characteristics. The study and correlation of the thermal relaxation processes were analyzed through static and dynamic measurements. Due to the intrinsic chemical characteristics and magnetocrystalline anisotropy of the ferrite nanoparticles, the energy barrier can be tuned to a range between 1100 K EB 7300 K, showing an alternative approach for tuning the magnetic dynamic properties, in contrast to the well-known mechanism through particle-size-effects. Specific loss power efficiencies were evaluated for the three ferrite samples. Comparing …

Highly Ordered Transition Metal Ferrite Nanotube Arrays Synthesized By Template-Assisted Liquid Phase Deposition, Amin Yourdkhani, Gabriel Caruntu

Chemistry Faculty Publications

Highly ordered spinel ferriteMxFe3_xO4 (M ¼ Ni, Co, Zn) nanotube arrays were synthesized in anodic aluminium oxide (AAO) templates with a pore size of 200 nm by combining a liquid phase deposition (LPD) method with a template-assisted route. The morphology of the transition metal ferrite nanotubes was characterized by electron microscopy (FE-SEM; TEM, SAED and HRTEM) and atomic force microscopy (AFM), whereas their chemical composition was determined by inductive coupling plasma (ICP). The phase purity was studied by X-ray diffraction (XRD) and the magnetic properties of the nanotubes were measured by SQUID measurements. Unlike the deposition of thin film structures, …