Investigation of dyes degradation intermediates with <Emphasis Type=Italic>Scytalidium thermophilum</Emphasis> laccase

Scytalidium thermophilum laccase was able to successfully decolourise Congo Red, Bromo-Cresol Green, Malachite Green, Phenol Red and Indigo Carmine under optimised conditions. The cited dyes belonging to three different classes were named azo, triarylmethane and indigoid. The decolourisation rates were 100, 95, 76, 57 and 22 mg h⁻¹ U⁻¹ for Indigo Carmine, Malachite Green, Bromo-Cresol Green, Congo Red and Phenol Red, respectively. The degradation products were characterised by UV–vis and FT-IR techniques, and their cytotoxicity was monitored. UV–visible absorption spectra and FT-IR analysis showed a complete degradation of Congo Red, Bromo-Cresol Green and Malachite Green, a partial degradation of Phenol Red and a transformation of Indigo Carmine. Toxicity study revealed that most of the treated dyes were less toxic than those before treatment, especially for Malachite Green. In fact, Scytalidium thermophilum laccase degraded Malachite Green into non-toxic products. Scytalidium thermophilum laccase constitutes a powerful tool for effective bioremediation of rich-dye textile effluents and was, therefore, found worthy of investigation for potential applications in restoration work and other biotechnological uses.     

Glass Powders with a High Content of Calcium Oxide: A Step Towards a “Green” Universal Biocide

It is shown that soda‐lime glass powders (d < 100 µm) with a content of CaO ranging from 15 to 20 wt‐% are strong inorganic biocide agents, with a logarithm of reduction > 4, versus Gram‐positive and Gram‐negative bacteria, and yeasts. First, the glass particles are attached to the cell membrane; then, the Ca²⁺ lixiviated from the glass particles surface brings about membrane depolarization and subsequent death of the cells.     

F2FMI: A toolkit for facilitating face-to-face mobile interaction

The importance of mobile groupware systems resides in the specific tasks that they can perform and other systems cannot. On the one hand, groupware systems allow groups of users to work together providing facilities that single-user systems are unable to offer. On the other hand, unlike stationary systems, mobile systems allow users to work on the move. The intersection of these two technologies offers a new support for activities, such as spontaneous collaboration, that could be facilitated neither by stationary groupware systems nor by mobile single-user systems. However, implementations of this new support are uncommon, probably because of the high development effort required and the seemingly little benefit obtained. In this paper, we aim to reduce this effort by facilitating the development of mobile groupware applications that support such activities. Our proposal to achieve this objective involves the design and implementation of the Face-to-Face Mobile Interaction (F2FMI) toolkit, whose goal is to provide generic and reusable software components required in most cases. We expect this strategy to yield a higher variety of successfully deployed applications, which in turn will demonstrate the benefits of supporting this kind of interactions through mobile devices.     

Multiscale failure analysis of fiber reinforced concrete based on a discrete crack model

In this work the capabilities of an interface model to predict failure behavior of steel fiber reinforced cementitious composites (SFRCCs) are evaluated at both macro and mesoscale levels of observation. The interface model is based on a hyperbolic maximum strength criterion defined in terms of the normal and shear stress components acting on the joint plane. Pre-peak regime is considered linear elastic, while the post-peak behavior is formulated in terms of the fracture energy release under failure mode I and/or II. The well-known ??Mixture Theory?? is adopted for modeling the interactions between fibers and the surrounding cementitious composite. The effects of both the axial forces on the fibers induced by normal relative displacements, as well as the dowel action due to tangential relative displacements in the interfaces are considered in the formulation of the interaction mechanisms between fibers and cementitious composites. After describing the interface model, this work focuses on numerical analyses of SFRCC failure behavior. Firstly, the validation analysis of the interface model is performed at the constitutive level by comparing its numerical predictions against experimental results available in scientific literature. Then, the sensitivity of the interface theory for SFRCC regarding the variation of main parameters of the composite constituents is evaluated. Finally, the attention is focused on Finite Element (FE) analysis of SFRCC failure behavior at meso and macroscopic levels of observation. The results demonstrate the capabilities of the interface theory based on the Mixture Theory to reproduce the main features of failure behavior of SRFCC in terms of fiber content and involved fracture modes.     

A new protocol for multi-biometric systems' evaluation maintaining the dependencies between biometric scores

We address the problem of measuring the dependency of multibiometric systems' scores, using Kolmogorov–Smirnov and Mutual Information criteria, and studying the validity of performance evaluation on chimeric persons. On the NIST-BSSR1 database, we formalize a common assumption in the literature: for independent scores, multibiometric systems can be evaluated on “random chimeric” persons. We show that this is not valid for dependent scores and propose a novel protocol for building “cluster-based chimeric” persons maintaining the level of dependency between scores. Finally, we show that performance evaluation for dependent modalities on such persons is equivalent to that obtained on “real” persons.     

Effect of a macromolecular coupling agent on the properties of aluminum hydroxide/PP composites

Polypropylene (PP)/aluminum hydroxide (ATH) composites were prepared in a melt mixer with addition of polypropylene functionalized with vinyltriethoxysilane (VTES) as a coupling agent. The effects of ATH and PP‐VTES on the melt flow indices (MFI), tensile properties, decomposition temperatures, and flame retardancy of composites were analyzed. It was verified that increased ATH concentration reduced MFI and tensile properties, but increased the decomposition temperature under oxidative atmosphere and improved the flammability properties. Addition of PP modified with VTES slightly improved tensile strength and maximum elongation and granted the best results for the flammability tests of the materials showing that it can be an effective coupling agent for PP/ATH composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1799–1805, 2006     

Toxicity evaluation of surface water treated with different disinfectants in HepG2 cells

It is well known that water disinfection through chlorination causes the formation of a mixture of disinfection by-products (DBPs), many of which are genotoxic and carcinogenic. To demonstrate the formation of such compounds, a pilot water plant supplied with water from Lake Trasimeno was set up at the waterworks of Castiglione del Lago (PG, Italy). The disinfectants, continuously added to pre-filtered lake water flowing into three different basins, were sodium hypochlorite, chlorine dioxide and peracetic acid, an alternative disinfectant used until now for disinfecting waste waters, but not yet studied for a possible use in drinking water treatment. The aim of this study was to evaluate the formation during the disinfection processes of some toxic compounds that could explain the genotoxic effects of drinking waters. Differently treated waters were concentrated by solid-phase adsorption on silica C(18) columns and toxicity was assessed in a line of human hepatoma cells (HepG2), a metabolically competent cellular line very useful for human risk evaluation. The seasonal variability of the physical-chemical water characteristics (AOX, UV 254 nm, potential formation of THM, pH and temperature) made indispensable experimentation with water samples taken during the various seasons. Autumn waters cause greater toxicity compared to those of other seasons, in particular dilution of the concentrate at 0.5l equivalent of disinfected waters with chlorine dioxide and peracetic acid causes a 55% reduction in cellular vitality while the cellular vitality is over 80% with the all other water concentrates. Moreover it is very interesting underline that non-cytotoxic quantities of the autumnal water concentrates cause, after 2h treatment, a decrease in GSH and a statistically significant increase in oxygen radicals, while after prolonged treatment (24h) cause a GSH increase, without variations in the oxygen radical content. This phenomenon could be interpreted as the cellular adaptation response to an initial oxidative stress.     

Formation of porous natural-synthetic polymer composites using emulsion templating and supercritical fluid assisted impregnation

Summary Porous natural-synthetic polymer composites were prepared using an alginate emulsion templating step followed by supercritical carbon dioxide (sc-CO₂) assisted impregnation (and subsequent polymerisation) of synthetic monomer mixtures. In the impregnation step, an initiator and either 2-hydroxyethylmethacrylate (HEMA), butylmethacrylate (BMA), ethyleneglycoldimethacrylate (EGDMA) or trimethylolpropanetrimethacrylate (TRIM) monomers, respectively, were used. After impregnation into the porous alginate foam, the synthetic monomer(s) were polymerised in situ, forming porous composites with increased stiffness. A number of methods were used to assess the effects of the impregnation/polymerisation process including uniaxial compression testing, scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), helium pycnometry and Fourier transform infra-red (FTIR) spectroscopy. Our results suggest that alginate foams impregnated with HEMA show higher weight gains and are stiffer than those impregnated with BMA. Such stiffer porous composites are potentially better suited than the unmodified materials in applications such as tissue engineering (cell-seeded) scaffolds, where mechanical conditioning is desired to stimulate cells for development of neo tissue growth.     

Biological Evaluation of Multivalent Lewis X–MGL‐1 Interactions

Myeloid C‐type lectin receptors (CLRs) expressed by antigen‐presenting cells are pattern‐recognition receptors involved in the recognition of pathogens as well as of self‐antigens. The interaction of carbohydrate ligands with a CLR can trigger immune responses. Although several CLR ligands are known, there is limited insight into CLR targeting by carbohydrate ligands. The weak affinity of lectin–carbohydrate interactions often renders multivalent carbohydrate presentation necessary. Here, we have analyzed the impact of multivalent presentation of the trisaccharide Lewis X (Le^X) epitope on its interaction with the CLR macrophage galactose‐type lectin‐1 (MGL‐1). Glycan arrays, including N‐glycan structures with terminal Le^X, were prepared by enzymatic extension of immobilized synthetic core structures with two recombinant glycosyltransferases. Incubation of arrays with an MGL‐1‐hFc fusion protein showed up to tenfold increased binding to multiantennary N‐glycans displaying Le^X structures, compared to monovalent Le^X trisaccharide. Multivalent presentation of Le^X on the model antigen ovalbumin (OVA) led to increased cytokine production in a dendritic cell /T cell coculture system. Furthermore, immunization of mice with Le^X‐OVA conjugates modulated cytokine production and the humoral response, compared to OVA alone. This study provides insights into how multivalent carbohydrate–lectin interactions can be exploited to modulate immune responses.