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Full-Text Articles in Chemistry
Cetyltrimethylammonium Halide-Coated Electrodes For The Detection Of Dopamine In The Presence Of Interferents, Amber J. Yeary
Cetyltrimethylammonium Halide-Coated Electrodes For The Detection Of Dopamine In The Presence Of Interferents, Amber J. Yeary
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Specially constructed carbon paste electrodes were coated with 10 mM cetyltrimethylammonium halide (CTAX) solutions, bromide and chloride being the counter anions. These surfactant modified electrodes were used to detect the catecholamine neurotransmitter dopamine using cyclic voltammetry. The coated electrodes gave reproducible quasi-reversible behavior for the analyte dopamine over a range of concentrations from 1 mM to 200 mM. When combined in solution with common interferents ascorbic acid (1 mM) and uric acid (300 μM), all cathodic and anodic current peaks maintained resolution at the biological pH of 7.4. When the coating solutions were below the critical micelle concentration (0.5 mM), …
Quantum Chemical Analysis Of The Pka's Of Alcohols And A Cellular Automata Model For The Distribution Of Gases In The Earth's Atmosphere, Edur Basha Boyinipalli
Quantum Chemical Analysis Of The Pka's Of Alcohols And A Cellular Automata Model For The Distribution Of Gases In The Earth's Atmosphere, Edur Basha Boyinipalli
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Alcohols play important roles in many chemical and biological processes, and their acid/base behaviors are often important for these roles. In this study we ask the question, "Can the electronic properties of these compounds offer clues to the compounds' acid/base behaviors?" The study considers whether selected quantum chemical properties can be used to find correlations with the experimental pKa's of the alcohols (aliphatic and aromatic). Calculations were carried out for these alcohols using the semi-empirical RM1 method and the more advanced density functional theory (DFT) B3LYP/6-31+G* method. Significant correlations were found for several quantum chemical descriptors. It was also found …
Synthesis Of Isatin Derivatives Used For The Inhibition Of Pro-Apoptotic Jurkat T Cells, Charles Michael Clay
Synthesis Of Isatin Derivatives Used For The Inhibition Of Pro-Apoptotic Jurkat T Cells, Charles Michael Clay
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A range of substituted 1H-indole-2,3-diones (isatins) was synthesized to assess their capability to inhibit caspases and prevent apoptosis in Jurkat T cells. The key steps in the synthesis of such molecules involved electrophilic substitution of the C-5 position of the isatin nucleus (if necessary), N-alkylation, Wolff-Kishner reduction of the C-3 carbonyl group and finally, Knoevenagel condensation. The design and synthesis of such potential inhibitors was guided by SAR studies of peptide based inhibitors such as "Q-VD-O-Ph", as well as small-molecule inhibitors based upon the isatins scaffold. Previously, 3-(2,6-difluorobenzylidene)-5-nitroindolin-2-one has been shown to inhibit apoptosis in human Jurkat T cells at …
Synthesis Of Fluorinated Indenofluorenediones And Bis(2-Fluorophenyl) Substituted Ppv, Jeffrey D. Fogle
Synthesis Of Fluorinated Indenofluorenediones And Bis(2-Fluorophenyl) Substituted Ppv, Jeffrey D. Fogle
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The compound 2,5-di(ethoxycarbonyl)-3,4-di(2-fluorophenyl)cyclopentadienone was successfully synthesized and led to the synthesis of terephthalates, di(hydroxymethyl)s, di(chloromethyl)s, diacids, diacid chlorides and indenofluorenediones having the pendent groups null, hexyl and 2-(4-benzothiazolyl)phenyl. All new compounds were characterized by melting point, IR, 1H NMR, 13C NMR, 19F NMR, GC/MS and combustion analysis. Most of the forementioned compounds showed an indication of restricted rotation with the appearance of trans and cis diastereomers. The asymmetric compounds showed the occurrence of four isomers. In some spectra, signals corresponding to all four isomers were visible. Through-space 1H-19F, 13C-19F and 19F-19F coupling was observed for most compounds in 1H NMR, …
Novel Trisubstituted Arylidene Oxindoles With Potent Anti-Apoptotic Properties, Paul J. Repasky
Novel Trisubstituted Arylidene Oxindoles With Potent Anti-Apoptotic Properties, Paul J. Repasky
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Apoptosis is a highly complex, multi-step cellular pathway utilized to initiate cell suicide. The family of enzymes largely responsible for the process is the cystienyl aspartic acid proteases (caspases). This study details the design and synthesis of a new class of small molecule caspase inhibitors, namely arylidene oxindoles, which are comparable to the isatin family of inhibitors but which offer the advantage of incorporating three points of variability into the basic scaffold. Moreover, whereas the mode of action of isatins against caspases has been demonstrated to involve nucleophilic addition of the cysteine residue of the enzymes to the C-3 ketone …
Near Equilibrium Dissolution Of Calcite Using A Flow-Through Reactor (Ftr), Michael Mante
Near Equilibrium Dissolution Of Calcite Using A Flow-Through Reactor (Ftr), Michael Mante
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In mineral dissolution reactions, surface morphologies play important roles particularly in near equilibrium fluids where generation of new sites of reactivity (e.g., pit nuclei) is thermodynamically disfavored. Following CO2 injection in geologic formations, dissolution of primary carbonate minerals and crack-sealing cements will occur. The impact of these reactions on fluid chemistry requires better understanding of the reaction kinetics of major minerals at close-to-equilibrium conditions. Initial investigations have focused on quantifying calcite dissolution using short residence time (~ 10 min) flow through reactors to obtain dissolution rates at 60°C, pH = 8.33 and Pco2 = 3.8 x 10-4 …
Routes To Acylated Sydnone Esters, Amanda Marie Balaguer
Routes To Acylated Sydnone Esters, Amanda Marie Balaguer
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Various 4-acyl-3-[2'-(carboalkoxy)phenyl]sydnones were synthesized by reaction of the parent sydnone with the corresponding anhydrides and Montmorillonite K-10. In the Q-tube, the acylation using acetic anhydride, which normally took 1.5 days for complete conversion thermally, was complete in 8.5 hours. Use of bismuth triflate as catalyst reduced the reaction time to 5 hours and, in the microwave, reactions were complete in 30 minutes and provided comparable yields. New sydnones were synthesized with acetic, propionic, butyric, and isobutyric anhydrides. Extension to various homogeneous metal triflates (lanthanum, yttrium, scandium, hafnium, gadolinium, and indium) was explored. Reactions were performed with 3-phenylsydnone as reactant, initially …
Cyclopentadienone Conversions To Terephthalates And Cycloadditions Of Alkynes And Azides, Sarah E. Bragg
Cyclopentadienone Conversions To Terephthalates And Cycloadditions Of Alkynes And Azides, Sarah E. Bragg
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Cyclopentadienone derivatives can be converted via a Diels-Alder reaction to multifunctional terephthalate derivatives, which can then be converted to poly(phenylene vinylene) derivatives. It was demonstrated that terephthalate derivatives can be simply and reproducibly synthesized from 2,5-diethoxycarbonyl-3,4-diphenylcyclopentadienone with a variety of acetylenes, having yields ranging from 63% to quantitative yields. The terephthalate derivatives synthesized varied from oils to crystalline solids, but were readily isolated and generally had high rates of completion despite expected steric factors. Terephthalate derivatives with pendent acetylenes were formed in reactions with as low as a 3:1 ratio of diacetylene to cyclopentadienone. A terephthalate derivative with a pendent …
Poly(Arylene Ether Sulfone)S Carrying Pendant(3-Sulfonated) Phenyl Sulfonyl Groups For Use As Proton Exchange Membranes, Kimberly E. Kern
Poly(Arylene Ether Sulfone)S Carrying Pendant(3-Sulfonated) Phenyl Sulfonyl Groups For Use As Proton Exchange Membranes, Kimberly E. Kern
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A series of poly(arylene ether)s, containing a pendant mono sulfonic acid group, was synthesized using 3-sulfonated-3', 5'-difluorodiphenyl sulfone and a variety of bisphenols for use in proton exchange membranes (PEM). Nucleophilic aromatic substitution was utilized for homo and copolymerizations. In addition, the relationship between perfectly alternating and random copolymers and their effects on overall properties was studied. Polymerization reactions yielded linear sulfonated poly(arylene ether)s, sPAEs, with molecular weights ranging from 15,400 to 212,000 g/mol. All of the polymers were characterized by gel permeation chromatography (GPC), 13C NMR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). All polymers exhibited excellent …
The Synthesis, Reduction, And Chlorination Of 5-Alkoxy-2,3-Diphenylterephthalates, Rachel Marie Sayers
The Synthesis, Reduction, And Chlorination Of 5-Alkoxy-2,3-Diphenylterephthalates, Rachel Marie Sayers
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A series of alkoxy, phenylated terephthalates has been synthesized as monomer precursors to the corresponding poly(phenylene vinylene)s (PPV). The hydroxy, phenylated terephthalate was synthesized via: 1) a Diels-Alder cycloaddition between an ethynyl boronic ester and a cyclopentadienone (CPD) with subsequent hydrolysis/oxidation of the boronate ester or 2) a Diels-Alder cycloaddition between vinylene carbonate and CPD followed by thermolysis of the bridged adduct. The hydroxy, phenylated terephthalate was alkylated via a phase-transfer reaction with iodomethane, propargyl bromide, benzyl chloride, allyl bromide, and bromobutane to produce the alkoxy, phenylated terephthalates in yields from 38.6- 91.1%. The alkoxyterephthlates were reduced with lithium aluminum …
Effects Of Crystal Orientation On The Dissolution Kinetics Of Calcite By Chemical And Microscopic Analyses, Michael Edward Smith
Effects Of Crystal Orientation On The Dissolution Kinetics Of Calcite By Chemical And Microscopic Analyses, Michael Edward Smith
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The purpose of this work was to examine the effects of polished crystal-surface orientation and degree of solution undersaturation (Ωcalcite) on the dissolution kinetics of calcite as a means of improving our understanding of fundamental reactions that may influence the efficacy of CO2 sequestration in geological formations. Crystallographic surface orientations utilized in this study included ~ 1 cm2 areas of natural calcite specimens polished approximately parallel to the (104) plane, giving rise to surfaces with flat terraces with few steps, as well as fully kinked surfaces created by sectioning approximately parallel to the (001) plane. Results …
Aerosol Jet Printing Of Lscf-Cgo Cathode For Solid Oxide Fuel Cells, Paul Gardner
Aerosol Jet Printing Of Lscf-Cgo Cathode For Solid Oxide Fuel Cells, Paul Gardner
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Solid oxide fuel cell (SOFC) technology has attracted great attention due to advantages such as low emissions and high efficiency. In this work, solid oxide fuel cells were fabricated by incorporating functional layers deposited by a novel aerosol jet® printing method. The buffer and cathode layers were printed from gadolinium doped ceria (Ce0.9Gd0.1)O1.95 (CGO) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) inks, respectively. The CGO layer was deposited on the sintered electrolyte and then LSCF was subsequently deposited onto the CGO layer. The polarization curves showed a 19% improvement in current density using LSCF as the cathode instead of LSM. Cathode grain size was …
Modifiable Hyperbranched Polyester Drug Delivery Systems, Dorothy Ogden
Modifiable Hyperbranched Polyester Drug Delivery Systems, Dorothy Ogden
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This work encompassed synthesis and characterization of biocompatible hyperbranched polyester drug delivery systems prepared with fumaric acid, glycerol and polyethylene glycol. The polymers were manufactured in the melt utilizing A2 + CB2 polymerization. The ratio of A2:CB2 was modified and excess B was added to end-cap the polymers to avoid cross-linking. Fumaric acid was selected as the A2 monomer because the double bond provided a site for polymer backbone modification or covalent attachment of active pharmaceutical ingredients. Acetaminophen and Ondansetron Hydrochloride were added to evaluate feasibility of using the polyesters as drug delivery systems. The weight average molecular weight of …