Synthesis,structure, spectral and coordination properties of a crown ether derivative of 1,3-indandione. A new structural evidence for the versatile reactivity of 2-acetyl-1,3-indandione

The current study describes the synthesis of a new 1,3-indandione derivative with conjugated N-phenylaza-15-crown-5 moiety (4). The crystal structure of compound 4 was solved and its optical properties were studied in various solvents and in presence of alkaline and alkaline-earth metal ions. Quantum chemical (DFT) methods were employed to describe the structure and the optical properties of the studied compound and its complexes. The obtained results indicated that the synthesis of compound 4 using acid-catalyzed aldol reaction between 2-acetyl-1,3-indandione and the corresponding aldehyde is accompanied with an unexpected deacetylation step. In this way, the N-phenylaza-15-crown-5 moiety is directly conjugated with the 1,3-indandione fragment, known as a very strong electron acceptor. Therefore, the absorption spectra of 4 are only slightly influenced by complexation with Ba²⁺ and Sr²⁺ ions.     

Pyruvate Oxidase Biosensors Based on Glassy Carbon Electrodes Modified with Carbon Nanotubes and Poly(Neutral Red) Synthesized in Ethaline Deep Eutectic Solvent

A novel nanostructured platform for pyruvate oxidase biosensors comprises poly(neutral red) (PNR) prepared by electropolymerization of NR in ethaline deep eutectic solvent (DES) with acid dopant, on a multiwalled carbon nanotubes (MWCNT) modified glassy carbon electrode (GCE). Characterization was by cyclic voltammetry and electrochemical impedance spectroscopy and morphology was examined by scanning electron microscopy. Ascorbate and H₂O₂ gave a better response at PNR_DES/GCE than at PNR_aq/GCE. Biosensors for pyruvate and phosphate, immobilizing pyruvate oxidase onto PNR_DES/MWCNT/GCE enabled selective determination of pyruvate and phosphate, with micromolar limits of detection. Pyruvate was determined in onion samples and phosphate in water samples.     

Ettringite instability analysis in the hydration process of the supersulfated cement

Journal of Thermal Analysis and Calorimetry - The search for new materials to replace Portland cement (PC) has increased due to the high release of carbon dioxide (CO2) and the exploration of raw...     

Varieties with equationally definable factor congruences

A variety has definable factor congruences if there is a first order formula φ which defines each factor congruence in terms of its associated central element. We study the case in which φ is a conjunction of equations.     

Nitrogen Source Optimization for Cellulase Production by Penicillium funiculosum, using a Sequential Experimental Design Methodology and the Desirability Function

The present study aimed at maximizing cellulase production by Penicillium funiculosum using sequential experimental design methodology for optimizing the concentrations of nitrogen sources. Three sequential experimental designs were performed. The first and the second series of experiments consisted of a 2⁴ and a 2³ factorial designs, respectively, and in the third one, a central composite rotational design was used for better visualizing the optimum conditions. The following nitrogen sources were evaluated: urea, ammonium sulfate, peptone, and yeast extract. Peptone and ammonium sulfate were removed from the medium optimization since they did not present significant statistical effect on cellulase production. The optimal concentrations of urea and yeast extract predicted by the model were 0.97 and 0.36 g/L, respectively, which were validated experimentally. By the use of the desirability function, it was possible to maximize the three main enzyme activities simultaneously, which resulted in values for FPase of 227 U/L, for CMCase of 6,917 U/L, and for β-glucosidase of 1,375 U/L. These values corresponded to increases of 3.3-, 3.2-, and 6.7-folds, respectively, when compared to those obtained in the first experimental design. The results showed that the use of sequential experimental designs associated to the use of the desirability function can be used satisfactorily to maximize cellulase production by P. funiculosum.     

Covalent Immobilization of Subtilisin A onto Thin Films of Maleic Anhydride Copolymers

Enzymes cleaving the biopolymer adhesives of fouling organisms are attracting attention for the prevention of biofouling. We report a versatile and robust method to confine the serine protease Subtilisin A (or Subtilisin Carlsberg) to surfaces to be protected against biofouling. The approach consists of the covalent immobilization of the protease onto maleic anhydride copolymer thin film coatings. High‐swelling poly(ethylene‐alt‐maleic anhydride) (PEMA) copolymer layers permitted significantly higher enzyme loadings and activities than compact poly(octadecene‐alt‐maleic anhydride) (POMA) films. Substantial fractions of the immobilized, active enzyme layers were found to be conserved upon storage in deionized water for several hours. Ongoing studies explore the potentialities of the developed bioactive coatings to reduce the adhesion of various fouling organisms.

     

Catalytic reduction of NO by CO over Pd — doped Perovskite-type catalysts

The perovskite type oxides (nominal formula LaTi_0.5Mg_0.5O₃) with addition of Pd were prepared by annealing the ethanol solution of precursors in nitrogen flow at 1200°C and characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption of NO (NO-TPD). Their activity was evaluated for NO reduction by CO under stoichiometric and oxidizing conditions and for direct decomposition of NO. Pd substituted samples exhibited high NO reduction activity and selectivity towards N₂. Nearly complete elimination of NO was achieved at 200°C. Two simultaneous reactions, NO reduction by CO and direct decomposition of NO as well as two forms of NO adsorption were observed on the surface of Pd substituted perovskite samples. The distribution of Pd in different catalytically active sites or complexes on at the catalyst surface may be responsible for the proceeding of two reactions: NO reduction with CO and direct NO decomposition.      

Vibration action on the human body into a tramway in traveling

This article presents the vibration action on the human body found in a tram travel, where made the vibration measurements. Also presented a mathematical model with two degrees of freedom. Finally a comparison was made between the results obtained from measurements and the results of integration. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)