Highly productive autocondensation and transglycosylation reactions with Sulfolobus solfataricus glycosynthase

Transglycosylation reactions (autocondensation of the substrate or transfer of the glycon donor moiety to different acceptors) with the hyperthermophilic glycosynthase from Sulfolobus solfataricus acting in dilute sodium formate buffer at pH 4.0 are reported; the use of 4-nitrophenyl beta-glucopyranoside as both donor and acceptor in the self-transfer reaction and a highly productive reaction with 1.1 M 2-nitrophenyl beta-glucopyranoside were possible. Interesting effects, governed by the anomeric configuration and lipophilicity of heteroacceptors, on the regioselectivity and yield of reactions were found for the first time with this enzyme and are discussed. The results demonstrate the unexplored synthetic potential of this glycosynthase; the tuning of the reaction conditions and the choice of different donors/acceptors can lead to products of applicative interest.     

NMR study of the lipid profile of mullet raw roe and bottarga

Samples of mullet (Mugil cephalus) roes from two different fishing areas were studied by means of ¹H, ¹³C and ³¹P NMR and GC techniques. The lipid fraction of unprocessed roes and that of the corresponding salted and dried commercial products “bottarga” were analyzed and the data compared. Roes of mullets from different origin showed different composition regarding mainly triacylglycerols, monounsaturated and n‐3 polyunsaturated fatty acids. The NMR spectra of processed roes, compared to those of the corresponding raw materials, showed a release of free fatty acids and the formation of other minor molecular components, such as free fatty alcohols, lysophospholipids, and diacylglycerols, thus indicating that hydrolytic processes were the main consequence of manufacturing. An increase of cholesterol ester concentration after processing was also detected. Through the analysis of the ³¹P NMR spectra, it was possible to follow the fate of the phospholipids and the formation of lysophospholipids induced by the salting and drying procedures.     

Synthesis and characterization of UV-curable nanocellulose/ZnO/AlN acrylic flexible films: Thermal,dynamic mechanical and piezoelectric response

This work is aimed at fabricating nanocomposites based on zinc oxide (ZnO) nanostructures and nanocellulose dispersed in a UV-cured acrylic matrix (EC) for application as functional coatings for self-powered applications. Morphological, thermal, and dynamic mechanical properties of the nanocomposites were characterized by X-Ray diffractometry (XRD), scanning electron microscopy, and differential scanning calorimetry. The piezoelectric behavior was evaluated in terms of root mean square (RMS) open circuit voltage, at different accelerations applied to cantilever beams. The generated voltage was correlated with ZnO nanostructures morphology, aluminum nitride film integration on the beam and proof mass insertion at the tip. Nitride layer increased the RMS voltage from 1 to 2.4 mV up to 3.9 mV (using ZnO nanoflowers). As confirmed by XRD analyses, the incorporation of ZnO nanostructures into the acrylic matrix favored an ordered structural arrangement of the deposited AlN layer, hence improving the piezoelectric response of the resulting nanocomposites. With proof mass insertion, the output voltage was further increased, reaching 4.5 mV for the AlN-coated system containing ZnO nanoflowers.     

TANGAEON: Tangible Interaction to Support People in a Mindfulness Practice

Recently, Tangible and Embodied Interaction (TEI) approaches to support people in mindfulness practices have been proposed in the literature, but they have scarcely explored the use of real natural elements in the interaction. In this article, we first present TANGAEON, a TEI system that augments the AEON mindfulness mobile app with an interactive, water-filled glass container. Second, we evaluate TANGAEON by contrasting it with two traditional mindfulness techniques and with AEON. TANGAEON obtained better results in terms of achieved mindfulness, perceived level of difficulty, and degree of pleasantness than the two traditional techniques. Moreover, considering all techniques, participants achieved the highest level of mindfulness with TANGAEON, and rated it as the most pleasant and preferred approach to practice. These results suggest that the use of TEI based on a natural element can offer a novel and effective way to help people approach and practice mindfulness, and to augment existing mindfulness apps.     

Coupling of Carbon Dioxide with Epoxides Efficiently Catalyzed by Thioether‐Triphenolate Bimetallic Iron(III) Complexes: Catalyst Structure–Reactivity Relationship and Mechanistic DFT Study

A series of dinuclear iron(III)^I complexes supported by thioether‐triphenolate ligands have been prepared to attain highly Lewis acidic catalysts. In combination with tetrabutylammonium bromide (TBAB) they are highly active catalysts in the synthesis of cyclic organic carbonates through the coupling of carbon dioxide to epoxides with the highest initial turnover frequencies reported to date for the conversion of propylene oxide to propylene carbonate for iron‐based catalysts (5200 h⁻¹; 120 °C, 2 MPa, 1 h). In particular, these complexes are shown to be highly selective catalysts for the coupling of carbon dioxide to internal oxiranes affording the corresponding cyclic carbonates in good yield and with retention of the initial stereochemical configuration. A density functional theory (DFT) investigation provides a rational for the relative high activity found for these Fe(III) complexes, showing the fundamental role of the hemilabile sulfur atom in the ligand skeleton to promote reactivity. Notably, in spite of the dinuclear nature of the catalyst precursor only one metal center is involved in the catalytic cycle.

     

The impact of chaotic advection on the microstructure of polymer‐modified bitumen

Owing to the high viscosity of the materials involved, mixing is often a critical step when processing polymer‐modified bitumen (PMB), directly influencing the microstructure and the stability of final products. We provide experimental evidence suggesting that laminar chaotic advection may prove a valuable strategy for obtaining a homogeneous and finely interdispersed polymer‐bitumen mixture in affordable time. As a case study, we investigate the mixing performance of a lab‐scale flat‐bottomed cylindrical vessel stirred by a radial impeller, either located symmetrically or eccentrically with respect to the vessel axis. The same geometries with a flat‐disk impeller are also considered for comparison. The Mix‐Norm is used in combination with image analysis as an objective measure of mixing performance. Results of mixing performance are independently validated by rheological tests. The experiments pinpoint kinematic chaos as the fundamental transport mechanism enhancing both the dispersion process and the microstructural quality of the resulting PMBs mixture. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1870–1879, 2014     

Thermal and mechanical properties of oxymethylene linked polymers

A series of novel polymers has been prepared by linking together copolymers of oxyethylene and oxypropylene with an oxymethylene link. Oxymethylene linked (OML) polymers have been made by a step polymerization reaction. Three different OML polymers have been synthesized starting from three different short chain triblock (ABA) copolymers of poly(oxyethylene) (A) and poly(oxypropylene) (B). These polymers have been characterized by gel permeation chromatography, differential scanning calorimetric analysis and Fourier transform infrared spectroscopy. The mechanical properties of the cast films and the rheological properties of aqueous solutions of these new polymers have been studied. It has been observed that it is possible to modulate the thermal and mechanical properties of these polymers by changing the starting materials. © 2000 Society of Chemical Industry