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High dielectric materials are of special interest in the production of electronic components such as in the manufacturing of transistors. Barium titanate (BiTiO3) nanoparticles have a strongly size-dependent dielectric constant that is lucrative for such materials. In this work, BiTiO3 nanoparticles were sorted according to size using filtration methods that changed their surface energy by silanation. These student-friendly methods are a cost effective way to size select particles for further study. These methods are of benefit to low budget labs or smaller universities that may be hindered by the absence of more accurate means to characterize particle size such as scanning electron microscopy.
236 UNDERGRADUATE POSTER ABSTRACTS
SYNTHESIS OF SELF-ASSEMBLING BISCAVITANDS FOR MOLECULAR RECOGNITION AND GUEST
COMPLEXATIONMaria Escamilla, Jeffrey Buenaflor, Linda Gutierrez-Tunstad.
California State University, Los Angeles, Los Angeles, CA.
Cavitands are container molecules that can bind or entrap smaller compounds. This study aims to synthesize a series of side-by-side biscavitands with linkers varying in flexibility to control their conformations. Resorcinarene cavitands serve as attractive frameworks for developing hexacarboxylic acid biscavitands due to their versatile structure. The biscavitand can potentially self-assemble into capsules through non-covalent electrostatic interactions such as hydrogen bonding. A thorough route utilizing conventional organic synthetic methods has been developed to incorporate functionality at specific locations on the resorcinarene for self-assembly and molecular recognition.
Characterization of these compounds will be completed using nuclear magnetic resonance spectroscopy. The conformational changes, guest complexation, and molecular recognition of functionalized biscavitands have not been well studied. By studying the physical properties of these compounds, we can better control conformational changes and guest complexation of future versions. These physical attributes make resorcinarene biscavitands suitable for potential applications as sensors, molecular switches, drug delivery carriers, or toxic remediatiors.
RISPERIDONE, AN ATYPICAL ANTIPSYCHOTIC, INCREASES THE EFFICACY OF CIPROFLOXACIN BY
FUNCTIONING AS AN EFFLUX PUMP INHIBITOR IN STAPHYLOCOCCUS AUREUSChristina Owens, Felix Mesak, Luis Mota-Bravo.
University of California, Irvine, Irvine, CA.
With the increase of multidrug bacterial resistance, the options for clinical treatment are becoming more been limited.
Ciprofloxacin, one of the most prescribed fluoroquinolones, has become less effective due to resistance by efflux pump in Staphylococcus aureus. In recent studies, it has been found that antipsychotics have efflux pump inhibition properties. The objective of this study is to test whether risperidone (RIS), an FDA-approved second-generation antipsychotic, is an efflux pump inhibitor (EPI) in Staphylococcus aureus, as well as examining its synergistic relationship with ciprofloxacin (CIP). Disk diffusion tests and a fractional inhibitory concentration (FIC) assay were performed to determine synergy between RIS and CIP. The accumulation and efflux of ethidium bromide (EtBr) in the
MANGANESE PHTHALOCYANINE AS A NEW FUNCTIONAL LAYER FOR THE DETECTION OF SMALL
ORGANIC COMPOUNDS IN BROAD-RANGE MEDIAFrancisco Colón, Mian Jiang.
University of Houston-Downtown, Houston, TX.
Porphrin and phthalocyanine have received increasing attention in agriculture, the dye industry, and photovoltanic design. In this work we have prepared manganese phthalocyanine (MnPc)-coated glassy carbon (GC) electrodes and studied their electrochemical behavior. MnPc is highly insoluble in water which makes it an ideal candidate for the heterogeneous catalysis (i.e., possible sensory implication). Our approach is the direct coating of MnPc from its organic solvent with controllable amount deposition. The resulting modified electrode is stable in the air and aqueous solution for at least 3 days. The film can withstand 500 cyclic voltammetric scans. For its potential application, we found MnPc/GC displayed catalytic oxidation to various small organic compounds including alcohols and monosugars. Further examination showed that this response can occur in wide-range pH media, not like the reported predominantly-alkaline media response. This new discovery expands the current sensing scope for alcohols and sugars into both ambient and extraordinary conditions. Preliminary analytical characterization of the proposed sensing was carried out and the operation parameters were optimized. Further mechanistic study is under way. [This work was supported by NASA-TSGC-NIP, SACP-UARP, Starter-award of UARP, and Welch Grant (BJ-0027).]
237 UNDERGRADUATE POSTER ABSTRACTS
DISTRIBUTION OF HEAVY METALS IN MORPHOLOGICAL TISSUES OF SAGITTARIA LANCIFOLIA, SURFACE
WATER, AND SEDIMENTS FROM THE CAÑO TIBURONES WETLANDAngel Arce-Cruz, Angelica Rosario, Luis Ramirez, Maiella Ramos.
University of Puerto Rico in Arecibo, Arecibo, PR.
The Caño Tiburones wetland in Arecibo, Puerto Rico, have been exposed to contamination by aqueous effluents produced by industrial activities, waste disposal sites, including the Arecibo Regional Landfill and other illegal dumps;
the Barceloneta Wastewater Treatment Plant near the reserve; local or municipal sewage; and agricultural activities, among others. The present work provides quantitative information about concentration levels and distribution of heavy metals such as manganese (Mn) in the aquatic plant Sagittaria lancifolia sediment, and surface water from the Caño Tiburones wetland. The research was carried out per yearly season: winter, summer, fall, and spring. Three sampling sites were selected in the wetland “Zanja fria” zone. For each sampling site, three plants, three sediment samples, and one sample of surface water were collected. Sagittaria lancifolia was divided into the root, stem, and leaf and were treated using a microwave-assisted method. Sediment was treated with EPA method 3050b and surface water with EPA method 200.1; each sample was analyzed using FAAS. Levels in the plant tissue ranged from 20 to 80 ppm in the leaf, 6 to 20 ppm in the stem, and 30 to 80 ppm in roots. In the water and sediment samples, results were 0.5 to 2 ppm in superficial water and 1 to 10 ppm in sediment. Standard reference materials were also used to ensure the reliability of the method used for digestion. Physicochemical parameters per yearly season were also collected using Vernier LabQuest. The use of Sagittaria lancifolia for phytoremediation is discussed using the BAF. More heavy metals will be analyzed in the future.
SYNTHESIS AND COMPARISON OF TWO TRIPODAL LIGANDS BEARING NITROGEN AND SULFUR DONORS
AND THEIR COORDINATION WITH RU(II)Jose Martinez, Margarita Gonzales, Pradip Mascharak.
University of California, Santa Cruz, Santa Cruz, CA.
Despite the toxicity of carbon monoxide (CO), this gaseous molecule is endogenously produced in the human body via the catabolism of heme by heme oxygenase. Once viewed as a toxic byproduct, CO has now been found to confer antiapoptotic, antiinflammatory, and regulatory properties when delivered in controlled doses. These recent findings on the biological relevance of CO have prompted our research group to synthesize photoactive CO-releasing molecules (photo CORMs) as a means of controlled CO delivery for therapeutic use. The project involves synthesis and characterization of two Ruthenium carbonyls as potential photo CORMs. To modulate the light-activated CO releasing capacities of the resulting metal complexes, we designed two tripodal ligands: (2-quinolylmethyl)-[2’-(methylthio) phenyl]imine (qmtpm) and (2-quinolylmethyl)-[2’-(methylthio)phenyl]amine (qmtpa), both bearing nitrogen and sulfur donors. The coordinating ability of qmtpm and qmtpa with Ru(II) centers will be examined. Characterizations of these photoCORMs will be performed using 1H NMR, electronic absorption, and infrared spectroscopy (IR). CO release in solution will be measured via a myoglobin assay. These methods will allow us to determine the binding aptitude, light absorption parameters, and CO-releasing properties of the resulting complexes. The difference in photosensitivity of our resulting compounds will indicate the significance of a meridional binding ligand (qmtpm) versus a facial binding ligand (qmtpa). The potential of these photoCORMs for therapeutic applications will be highlighted.
OXIDATION OF NITROGEN HETEROCYCLIC COMPOUNDS USING MOLYBDENUM(VI) OXIDE AS A CATALYSTJacob Sollner, Jason Parsons.
University of Texas-Pan American, Edinburg, TX.
In the present work, the oxidation of quinoline and 1,2,3,4-tetrahydroquinoline to form quinoline 1-oxide and 1-oxotetrahydroquinolinium, respectively, was achieved through a simple oxidation reaction. The oxidation of the compounds was achieved through the use of decahydronaphthalene as a solvent and molybdenum (VI) oxide as a catalyst without the addition of any peroxide or organic acid. The reaction was studied at different temperatures ranging from 140 °C to 180 °C. The reaction mixture and products were analyzed using GCMS to confirm that the oxidation products of the quinoline and 1,2,3,4-tetrahydroquinoline reactions were quinoline 1-oxide and 1-oxotetrahydroquinolinium. Additional analysis techniques included FTIR and RAMAN. XRD analyses were also used to confirm the catalyst remained unchanged after the reaction. In addition, studies of the reaction kinetics will be presented for the reaction performed at 140 °C, 150 °C, 160 °C, 170 °C, and 180 °C.
238 UNDERGRADUATE POSTER ABSTRACTS
SHOWALTER LIMIT OF THE BELOUSOV-ZHABOTINSKY REACTIONTamunoisoala LongJohn, James Wepy, Emma Kast, Sabrina G. Sobel, Harold M. Hastings.
Hofstra University, Hempstead, NY.
The ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction is the prototype excitable chemical reaction system. In oscillatory reagent mixtures with sufficiently high concentrations of proton (H+) and bromate (BrO3-), the unstirred BZ reaction produces spontaneous blue waves of oxidization in a red, reduced, low ferriin medium. This occurs after an induction period of approximately 3.5 minutes in reagent mixtures with initially added bromide (Br-). At lower [H+] and [BrO3-], the reaction only produces these waves in response to stimuli, such as local reductions of [Br-]. The boundary between auto-oscillatory and excitable dynamics, where excitations do or do not occur spontaneously, known as the Showalter limit, is usually stated in terms of the product of [H+] and [BrO3-]. In experiments, varying initial [H+] and [BrO3-] caused variations in induction periods, oscillation periods, and excitability. In particular, we found the Showalter limit more dependent on initial [BrO3-] than on initial pH. Oscillation periods appear more dependent on initial pH. In addition, theoretical work explored how nonlinear chemistry affected oscillation periods by sinusoidally oscillating input conditions (specifically pH) to elicit changes in the system. Theoretical data generated using WinPP, an ordinary differential equation solver, were produced using the Oregonator model and will be further compared with experimental data this summer. The results of these experiments have the potential to offer a further understanding of pattern formation in many biological processes. The patterns that form during the BZ reaction mimic those of many biological processes, including irregular nerve signaling during heart arrhythmia and bacterial cell signaling.
THEORETICAL STUDIES OF CO(SALEN) COMPLEXES WITH GREEN CHEMISTRY APPLICATIONSJessica Rhone, Maria Benavides.
University of Houston-Downtown, Houston, TX.
Ionic liquids and their properties have advanced the world with their multiple applications in green chemistry. Taskspecific ionic liquids (TSIL) are ionic liquids that have been functionalized so they can perform specific functions, such as the chelation of metal ions. Our study focuses on two cobalt (III) complexes, referred to as Co(salen) complexes, which are prepared from the coordination of Co(III) and 2 imidazolium-based TSIL compounds. It is important to study these complexes because they have significant applications in the recycling of metals from ore,
CHARACTERIZATION AND SEPARATION OF BRANCHED AMINO ACID BASED SURFACTANTS USING
CAPILLARY ELECTROPHORESISJeremias Georgiadis, Manuel Garza, Fereshteh Billiot, Eugene Billiot.
Texas A&M University-Corpus Christi, Corpus Christi, TX.
Five branched amino acid based surfactants have been synthesized and used to separate chiral enantiomers as pseudostationary phases in capillary electrophoresis. Three reactions were used for the synthesis of the dipeptide and tripeptide surfactants: the formation of N-hydroxysuccinimide esters, the formation of peptide bonds, and the deprotection of tert-butyl esters. Nuclear magnetic resonance (NMR) spectroscopy and high-performance liquid chromatography (HPLC) were used to check the purity of the surfactants. These surfactants were used to separate enantiomers of 8 chiral analytes in capillary electrophoresis. Preliminary studies showed separation of the enantiomers of 3 of the 5 analytes.
239 UNDERGRADUATE POSTER ABSTRACTS
EFFECTS OF FIBER ALIGNMENT ON MECHANICAL PROPERTIES AND MOLECULAR STRUCTURE OF
ELECTROSPUN POLYURETHANESAllison Siehr, Javier Macossay.
University of Texas-Pan American, Edinburg, TX.