Message authentication algorithm for OFDM communication systems

Telecommunication Systems - With the huge expansion in the telecommunications industry, the need for robust information security is becoming more critical than ever. Physical Layer Security has,...     

Enabling fast and energy-efficient FM-index exact matching using processing-near-memory

The Journal of Supercomputing - Memory bandwidth and latency constitutes a major performance bottleneck for many data-intensive applications. While high-locality access patterns take advantage of...     

Rheological properties and stability of low-in-fat dressings prepared with high-pressure homogenized yeast

The aim of present study was to investigate the feasibility of application high-pressure homogenized (HPH) yeast aqueous dispersions with low nucleic acid content for the formulation of low-in-fat dressings. The HPH treatment (1500 bar, 3 passes) in alkaline medium improved the protein dispersibility (>50%). Emulsions were prepared using sunflower oil (12.0% or 25% w/w oil), xhantan/guar gums (0.5% w/w), modified starch (0–4.0% w/w), salt, sucrose, acidulants, EDTA, and antimicrobial agents. All emulsions (pH 3.97 ± 0.27; a_w = 0.97 ± 0.01), whatever the starch content, behaved clearly as pseudoplastic fluids in steady flow measurements. Moreover, as the frequency sweep measurements were made they also exhibited a weak gel behavior. Although the presence of starch produced an increase of mean particle size (D_3,2 values), the rheological parameters (consistency index, proportionality coefficient and coordination number) also increased, so that the starch contributes to reinforce the three-dimensional network formed by oil droplets, protein aggregates and other polysaccharides. Yeast dressings were stable to coalescence after 28 days of quiescent storage (7.0 ± 0.5 °C) and only the highest starch concentration at 25% w/w oil was sufficient to maintain the stability of network.     

Rheological and electrical percolation thresholds of carbon nanotube/polymer nanocomposites

Percolation thresholds of multiwalled carbon nanotube/polystyrene (MWCNT/PS) nanocomposites (NC) were determined by rheology and electrical conductivity. The percolation threshold found by electrical conductivity was 0.5% carbon nanotubes (CNT) and that by mechanical spectroscopy and relaxation measurements was 0.9% CNT. These results together with those reported in the literature show several types of percolation thresholds, depending on the average filler–filler (CNT and/or aggregates) distance in a polymer matrix. A distance close to polymer gyration radius corresponds to a “soft” rheological threshold (P_{C rheo}^soft). Close contacts between fillers giving rise to a conductive path corresponds to an electrical threshold (P_{C elec}). At high filler concentration, fillers form a network, corresponding to a “rigid” rheological threshold (P_{C rheo}^rigid). These thresholds depend on the filler content and follow the order: P_{C elec}^soft < P_{C elec} < P_{C rheo}^rigid. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Non‐Magnetic and Magnetic Supported Copper(I) Chelating Adsorbents as Efficient Heterogeneous Catalysts and Copper Scavengers for Click Chemistry

Novel supported chelating adsorbents bearing diverse multidentate nitrogenated ligands with strong copper(I) affinities are easily prepared in non‐magnetic and magnetic variants using silica and silica‐coated magnetite nanoparticles as suitable supports and the aza‐Michael‐type addition of vinyl sulfones as the ligation tool. These adsorbents are versatile materials with applications in the copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) click chemistry where their complexation abilities enable them to act either as heterogeneous click catalysts when used in their complexed form or as copper(I) scavengers when used in their uncomplexed form. In the first instance, they proved to be robust and efficient heterogeneous catalysts to promote click reactions using extremely low doses and showing negligible copper leaching, particularly in the case of the silica‐based non‐magnetic adsorbents, allowing a simple operational protocol for their rapid and easy removal by filtration or magnetic decantation and showing good recyclability properties. In their uncomplexed form, the non‐magnetic chelating adsorbents are very efficient copper scavengers that are able to remove any traces of metal contamination and that can be applied in tandem with any heterogeneous supported copper(I) catalysts or as stand‐alone copper removing system in any click protocol allowing the isolation of metal‐free clicked compounds.