Solution and Solid‐State Studies on the Halide Binding Affinity of Perfluorophenyl‐Armed Uranyl–Salophen Receptors Enhanced by Anion–π Interactions

The enhancement of the binding between halide anions and a Lewis acidic uranyl–salophen receptor has been achieved by the introduction of pendant electron‐deficient arene units into the receptor skeleton. The association and the occurrence of the elusive anion–π interaction with halide anions (as tetrabutylammonium salts) have been demonstrated in solution and in the solid state, providing unambiguous evidence on the interplay of the concerted interactions responsible for the anion binding.     

Thermal hardening and structure of a phosphorus containing cementitious model material

The reaction of phosphoric acid with wollastonite has been studied for reaction mixtures with a molar ratio r=P/Ca from 0.39 up to 2.9. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) reveal the formation of the crystalline products brushite (when r is smaller than 1.4) and monetite and calcium dihydrogenphosphate monohydrate (when r is above 1). Magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) and FTIR show that amorphous silica is also formed which contains some residual calcium and hydroxyl groups. The proposed reactions are confirmed by the evolution of the reaction enthalpy measured with differential scanning calorimetry (DSC). The reaction was monitored with temperature modulated DSC (TMDSC) and dynamic mechanical analysis (DMA). The sharp increase of the elasticity modulus coincides with the onset of decrease in heat capacity. The setting of the reaction mixture does not slow down the reaction rate.     

A numerical methodology for thermo-fluid dynamic modelling of tyre inner chamber: towards real time applications

Meccanica - The characterization and reproduction of tyre behaviour for vehicle modelling is a topic of particular interest both for real-time driver in the loop simulations and for offline...     

Effects of indium doping on the superconducting properties of YBa2Cu3Oy sintered compounds and thin films

We investigated the effects of indium doping on the superconducting properties of YBCO sintered samples and thin films. In₂O₃-doped YBCO and YBa₂Cu_3−xIn_xO_y sintered samples showed a gradual decrease in the critical temperature (T_c) with increasing indium content; however, a T_c value above 80 K was maintained even up to 30 vol.% addition and x = 0.4, respectively. Ba₃Cu₃In₄O₁₂ was detected by X-ray diffractometry and energy-dispersive X-ray spectroscopy as a reaction product for both sintered samples. The normalized J_c under a magnetic field of 0.1 T showed a maximum at x = 0.3. Indium-doped YBCO films prepared by pulsed laser deposition showed a similar dependence of T_c on indium content as the sintered samples.     

Silver electrodeposition from water–acetonitrile mixed solvents and mixed electrolytes in the presence of tetrabutylammonium perchlorate. Part I—electrochemical nucleation on glassy carbon electrode

Nucleation and growth of silver, electrodeposited from water–acetonitrile (CH₃CN from 0 to 100% by volume) mixed solvents on glassy carbon electrodes, was studied by means of double-sweep voltammetry, current–time transients (CTT) and scanning electron microscopy (SEM). The effects of the addition of the specifically interacting tetrabuthylammonium cation were also investigated. From voltammetries, the formal potential, the nucleation potential and the cathodic current efficiency have been evaluated as a function of the mixed solvent composition. The key role on nucleation kinetics of transferring Ag⁺ from the bulk phase to the CH₃CN-enriched electrode/solution interphase has been highlighted. CTT transients were described by a model combining instantaneous and progressive nucleation mechanisms. SEM images highlighted the effects of the presence of the organic solvent, which yields to a more regular growth, and of the quaternary ammonium salt, which exhibits grain-refining properties.     

Simple confirmatory assay for analyzing residues of aminoglycoside antibiotics in bovine milk: hot water extraction followed by liquid chromatography-tandem mass spectrometry

A simple, selective and sensitive procedure for determining nine widely used aminoglycoside antibiotics (AGs) in bovine whole milk is presented. It is based on matrix solid-phase dispersion with heated water, at 70 degrees C, as extractant followed by liquid chromatography (LC)-tandem mass spectrometry (MS) using an electrospray ion source. After acidification and filtration, 0.2 ml of the aqueous extract was injected into the LC column. MS data acquisition was performed in the multi reaction monitoring mode, selecting two (three, when possible) precursor ion > product ion transitions for each target compound. Analyte recoveries ranged between 70 and 92%. Using aminosidine (an AG not used in veterinary medicine) as surrogate internal standard, the accuracy of the method at three spike levels varied between 80 and 107% with R.S.D. not larger than 11%. The limits of quantification were between 2 ng/ml (apramycin) and 13 ng/ml (streptomycin). They are well below the tolerance levels set by both the European Union and the U.S. Food and Drug Administration.     

End‐group modified poly(methyl vinyl ether): Characterization and LCST demixing behavior in water

A range of hydrophilic poly(methyl vinyl ether) (PMVE) polymers was synthesized by living cationic polymerization of methyl vinyl ether (MVE), having different hydrophilic or hydrophobic chain‐end functionalities. The dissimilar end‐groups were either introduced by end‐capping of the growing polymer chain with LiBH₄, methanol, and water or by functional initiation with 2‐bromo‐(3,3‐diethoxy‐propyl)‐2‐methylpropanoate. The synthesized PMVEs were characterized by ¹H NMR, size exclusion chromatography, and matrix‐assisted laser desorption ionization time of flight, displaying a narrow polydispersity. Modulated temperature DSC was applied to study the influence of the nature of the end‐groups on the solubility behavior of PMVE in water. Terminal‐modification with a hydroxyl function improves the solubility, whereas a Br‐containing end‐group causes the polymer to be insoluble in water at room temperature; however, the special type III lower critical solution temperature demixing behavior being maintained. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 461–469, 2006     

Monoaza[5]helicenes. Part 2: Synthesis, characterisation and theoretical calculations

The synthesis of four different monoaza[5]helicenes is reported, to complete the whole series of these compounds, so that systematic studies on their properties can be carried out. They were fully characterised via NMR. A theoretical approach to explain why ring closure occurs to give the most crowded compound is reported, in comparison with earlier calculation methods.