Now showing items 13495-13514 of 14830

    • Synthesis of esters of diglycerol

      Raica, Nicholas, 1920- (The University of Arizona., 1954)
    • Synthesis of lower order model for stable complex systems

      Zarrabi, Fazollah (The University of Arizona., 1979)
    • Synthesis of monomers for possible conducting polymers

      Jasek, Thomas Adolph (The University of Arizona., 1978)
    • Synthesis of Monomers for the Development of Novel Polymers

      Mash, Eugene A.; Anthony, Spencer Patrick; Hruby, Victor; Walker, Anne (The University of Arizona., 2011)
      This research had the specific goal of synthesizing a monomer for the development of polymers with unique physical properties. The expected physical property to be pursued is that of an innate elasticity within the monomer itself. As such, bis-1,10-((6-azidohexyl)oxy)bicyclo[8.8.8]hexacosane (target 1) was synthesized with the expectation that the bicyclic core would have the freedom of movement necessary to provide such elasticity. The addition of the azide functional groups to the target molecule may be used in the well known Huisgen 1,3-cycloaddition reaction to form a polytriazole polymer when matched with another monomer containing the requisite terminal alkyne. For this purpose, and further study of the elasticity of the bicyclo[8.8.8]hexacosane core, bis-1,4-((5-hexynyl)oxy)benzene (target 4) was synthesized for the formation of the polytriazole, and bis-1,4-((6-azidohexyl)oxy)benzene (target 5) was synthesized to form a polytriazole analog without the elastic bicycle in the polymeric repeating units.
    • Synthesis of Novel Biologically Active Peptide Analogues that are Agonists at Opioid Receptors and Antagonists at Cholecystokinin Receptors

      Wooden, Ekaphol; Hruby, Victor J. (The University of Arizona., 2005)
      We know that many disease states lead to changes in expressed proteins. Therefore, drug design and discovery based on normal states and single targets often is inadequate. The "system changes" that occurs must be considered in any treatment for the disease, clearly evident in neuropathic pain where opioids can actually heighten pain. To effectively treat diseases involving "systems changes" a new paradigm was recently introduced. In this new approach single peptide molecules are designed to interact with multiple receptor targets. For the treatment of pain, a series of linear and cyclic peptides were designed based on the overlapping pharmacophores of opioid and CCK ligands. The opioid/CCK analogues were synthesized and evaluated for their biological activities. Several analogues were found to simultaneously interact with opioid receptors as agonists and CCK receptors as antagonists. This study further modifies the RSA analogues to improve on the bioassays of the previous peptides.
    • Synthesis of Novel Hybrid Adsorption-Permeation Adsorbents for Effective Separation of Peptides and Small Proteins

      Guzman, Roberto; Diaz, Daniel Alejandro; Saez, Eduardo; Gervasio, Dominic (The University of Arizona., 2019)
      The main objective of this work was to synthesize new adsorbents for the isolation and separation of peptides and small proteins from mixtures of larger biomolecules found in biological fluids. This was done by constructing hybrid gels with both adsorption and size-exclusion chromatography (AdSEC) characteristics on the same matrix. The ligands were reacted onto the surface to create adsorption sites. The ligands functionalized onto surface were chelating agents including iminodiacetic acid (IDA), dipicolylamine (DPA), carboxymethylated ethylenediamine (CEDA), tripicolylamine (TPA) and amino acids including arginine, lysine, glycine, aspartic acid, phenylalanine, asparagine, and histidine and a couple derivatives of ethylenediamine (EDA). The hindrance permeating compound used in all these AdSEC gels was the polymer methyl polyethylene glycol amine (m-PEG-NH2). Proof of concept was performed with synthesized IDA-PEG-m AdSEC gels to perform separations of amino acids from bovine serum albumin (BSA) solutions. Studies were also performed with DPA-PEG and with carboxymethylated ethylenediamine (CEDA)-PEG derivatives. Tests with DPA and CEDA included sample solutions containing different peptides. Functionalized gel analysis showed that reaction times of both the specific adsorption ligand and the permeation polymer PEG onto the matrix is the most important parameter to produce optimal adsorption-permeation chromatographic matrices for effective separation of larger and small molecular weight biomolecules. The new gels synthesized in this work offer an effective tool to isolate and separate target biomolecules from complex biological mixtures such as blood, urine, sweat and tears.
    • Synthesis of Novel Linear Multivalent Peptide Ligands Based on the Tetrapeptide MSH(4)

      Mash, Jr., Eugene A; Sterne, Robert; Mash, Jr., Eugene A; Ghosh, Indraneel; Polt, Robin (The University of Arizona., 2010)
      This thesis describes the synthesis of a novel multimeric peptide ligand targeted to the human melanocortin 4 receptor. The synthesis of the peptide was attempted both by solid phase peptide synthesis and by solution phase peptide synthesis, leading to the conclusion that the necessary C- and N- terminal substituents were much easier to install via the solution phase route. The bifunctional peptide was purified and then multimerized in both protected and active amino acid forms using the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction. The multimers were characterized using MS and UV-Vis spectroscopy. It was found that a large portion of the monomer cyclized under CuAAC conditions, though sufficient multimerization took place to form up to nonamers, as determined by mass spectrometry.
    • Synthesis of Pd(II) Complexes Containing Redox-active Dipyrrolic and Tripyrrolic Ligands

      Tomat, Elisa; Curtis, Clayton; Lichtenberger, Dennis; Loy, Douglas (The University of Arizona., 2018)
      Redox-active ligands represent a large class of molecules that have multiple applications in the field of catalysis. This is due, in part, to their ability to undergo redox transformations independently of the metal center; thus, expanding the redox capabilities of many transition metals. Recently the Tomat lab examined the coordination chemistry of two linear oligopyrroles, propentdyopent and tripyrrindione, to divalent transition metals. It was determined that each of these ligands were capable of hosting redox events and were therein considered to be redox-active. The focus of this thesis is to expand upon this work and explore the properties of these ligands. Chapter 1 presents and introduction to redox-active ligands with a focus on applications in catalysis, while also discussing the relevance to oligopyrrolic ligands this area. Chapter 2 focuses on the dipyrrindione ligand propentdyopent, and details the synthesis of a series of heteroleptic PdII complexes which contain intramolecular hydrogen bonds. The effect of these hydrogen bonds on the redox potential of the propentdyopent scaffold will be examined. Chapter 3 describes synthetic modifications to the tripyrrindione ligand through alkylation of the C1 and C14 carbonyl groups, and how these modifications effect the resulting PdII complex’s electrochemical profile. Chapter 3 will also explore the reactivity of the tripyrrindione ligand with nitriles under anaerobic conditions.
    • Synthesis of sequences of summer thunderstorm volumes for the Atterbury Watershed in the Tucson area.

      Sariahmed, Abdelwaheb,1939-; Kisiel, Chester C. (The University of Arizona., 1969)
      In this study an attempt is made to represent summer thunderstorm occurrences in the Tucson area using simple probabilistic principles and a digital computer. The purpose of the model is to forecast many of the characteristics of the summer thunderstorms (storm duration; time between storms; storm depth; and daily, monthly, and seasonal totals, etc.). The synthetic data exhibits many of the characteristics of the historical sequences. However, the correlation between storm depth and storm duration Is weaker for the synthetic data than for its historical counterpart. The model conserves the historical values of mean rainfall (seasonal, monthly, daily totals).
    • The synthesis of seven-membered heterocycles

      Hopps, Harvey Byron, 1934- (The University of Arizona., 1958)
    • Synthesis of single-loop non-unity feedback systems

      Roe, George Francis, 1930- (The University of Arizona., 1958)
    • Synthesis of some bicyclo (3.2.2.) nonanes

      Moran, Michelle Delphine, 1938- (The University of Arizona., 1963)
    • Synthesis of submicron copper coated polystyrene particles by electroless deposition

      Raghavan, Srini; Chowdhury, Rina, 1965- (The University of Arizona., 1991)
      A method for the synthesis of submicron copper coated polystyrene particles by electroless deposition has been developed. In this technique, the carboxylated and sulfated polystyrene latex particles of 0.1 μm and 0.24 μm diameter, are first activated by conditioning in a solution of tetraammine palladium (II) chloride monohydrate and then plated in an electroless bath containing cupric sulfate, EDTA-disodium salt, some stabilizers and basic formaldehyde at 72 ± 1°C. The interaction between carboxylic acid groups and Pd(NH₃)₄Cl₂.H₂O has been studied using uv spectroscopy. Copper coated carboxylated polystyrene particles with a mean diameter of 0.4 μm and a standard deviation of 9% of the mean diameter have been synthesized. The size, shape and purity of these particles have been determined by SEM, EDX, and ESCA analysis. The microcrystallinity of the particles has been determined by XRD technique.
    • Synthesis of Upconverting Nanoparticles for Temperature Sensing Applications

      Romanowski, Marek; Joshua, Gihan Sumith; Pagel, Marty; Matsunaga, Terry; Yoon, Jeong-Jeol (The University of Arizona., 2012)
      Lanthanide-doped nanoparticles have been increasingly gaining attention as possible contrast agents due to their unique upconversion luminescence properties. The luminescence of certain emission bands from NaYF4 :Er3+/Yb3+ nanoparticles are also temperature dependent, and can be used as a ratiometric temperature sensor by monitoring the green-to-red emission ratio. The objective of this study was to reproducibly synthesize NaYF4:Er3 +/Yb3+ nanoparticles, use them to create a thin film on a glass surface, and visualize temperature changes on this coated surface. Nanoparticles were prepared via thermal decomposition at 300° C, underwent an acid treatment process to remove the oleate ligands from their surfaces, and were introduced to glass slides that had been functionalized with carboxyl groups. The temperature of the coated glass slide was varied, and images taken using a CCD camera were used to construct the green-tared emission ratio, which showed a linear trend with respect to increasing temperature.