Engineered organic/inorganic hybrids for superhydrophobic coatings by wet and vapour procedures

Siloxane/oxide hybrids have attracted growing attention thanks to their ability to modulate the surface energy, wettability, or self-lubricity of a material. Here, we compare two functionalisation procedures (chemical vapour deposition and wet impregnation) on substrate films composed by preformed oxide particles. Three kinds of particles, characterised by different natures (SiO₂ and TiO₂) and average particle size, were studied to highlight possible effects related to the chemical and morphological state of the substrate surface. Morphological characterisations were carried out using dynamic light scattering and scanning electron microscopy, while the structure of the hydrophobing layer was studied by combining Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance. The degree of functionalisation and the features of the siloxane layer vary significantly among the adopted oxides and functionalisation methods. The wettability features of the different hybrids closely mirror the results of the spectroscopic characterisations, giving rise to either Lotus leaf or patch-wise hydrophobic systems depending on the adopted conditions.     

Proteomic analysis of water soluble and myofibrillar protein changes occurring in dry-cured hams

The myofibrillar fraction of raw ham muscles and dry-cured hams with different ripening times was extracted in denaturing and reducing conditions and subjected to two-dimensional gel electrophoresis. The two-dimensional maps gave overall pictures of the already noted progressive disappearance of actin, tropomyosin and myosin light chains during ripening. In addition, two fragments from Myosin Heavy Chain proteolysis, marked as myosin chain fragments MCF1 and MCF2, were identified by immunodetection and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Furthermore, a new form of actin on two-dimensional gel was identified by MALDI-TOF peptide mapping. In 12-month-old dry-cured ham, most myofibrillar proteins were completely hydrolyzed. At this stage of ripening, in fact, in some Parma and S. Daniele dry-cured ham samples, myosin heavy chain fragments and other unidentified neo-formed spots were found. Some of the sarcoplasmic proteins in water extracts from pork meat markedly decreased in amount or disappeared totally, during ripening. Surprisingly, two-dimensional gel electrophoresis maps of the water soluble protein fraction from dry-cured ham showed the presence of two spots identified as tropomyosin α- and β-chain. This result suggests that some of the saline soluble myofibrillar proteins can disappear from this fraction because of salt solubilization and not due to complete enzyme action. Two-dimensional gel electrophoresis (2-DGE) has proved a powerful tool to evaluate the enzymatic susceptibility of meat proteins and the evolution of protein map fragmentation throughout ripening process as well as a means of obtaining a standard fingerprinting map characterizing the final product.     

Candida colonization index in patients admitted to an ICU

Multiple-site colonization with Candida spp. is commonly recognized as a risk factor for invasive fungal infection in critically ill patients. We carried out a study to determine the relationship between Candida colonization and invasive infection in neurological patients admitted to an ICU. At admission (T0) and every three days for two weeks, different samples (pharynx swab, tracheal secretions, stomach contents, etc.) were collected for mycological surveillance. Candida mannan antigen and Candida anti-mannan antibodies were assayed. The Colonization Index (CI) and Corrected Colonization Index were calculated for each time point. Of all patients 70% was already colonized by Candida spp. at T0 and six of them had CI ≥ 0.5. Three patients developed candidemia; they had CI ≥ 0.5 before infection. Positive values of Candida mannan antigen and anti-mannan antibodies were found only in the patients with candidemia. The sensitivity and specificity of the Candida mannan test were 66.6% and 100%, respectively, while the sensitivity and specificity of the anti-mannan antibody test were 100%. In accordance with other authors, we find the surveillance cultures are useful to monitor the Candida colonization in ICU patients. In addition, the sequential observation of anti-mannan antibodies could contribute to early diagnosis of candidiasis more than Candida mannan antigen in immunocompetent patients.     

AFLP variability, toxin production, and pathogenicity of Alternaria species from Argentinean tomato fruits and puree

Large amounts of tomato fruits and derived products are produced in Argentina and may be contaminated by Alternaria toxins. Limited information is available on the genetic variability, toxigenicity, and pathogenicity of Alternaria strains occurring on tomato. We analyzed 65 Alternaria strains isolated in Argentina from tomato fruits affected by black mould and from tomato puree, using amplified fragment length polymorphisms (AFLPs) technique. AFLP analysis resolved the set of strains in 3 main clusters (DICE similarity values of 58 and 60%) corresponding to A. alternata/tenuissima (44 strains), A. arborescens (15 strains) and to an unknown group (6 strains). Most of the representative strains, belonging to each AFLP cluster, when cultured on rice, produced tenuazonic acid (up to 46,760 mg/kg), alternariol monomethyl ether (AME, up to 1860 mg/kg), and alternariol (up to 70 mg/kg). The toxin profile related to the strains was not related to any AFLP cluster, except for AME which was produced at lower level by A. arborescens. Most of strains were pathogenic on two types of commonly cultivated tomato fruits. These findings provide new information on the variability within the Alternaria species complex associated with tomato disease.     

UV/Vis visible optical waveguides fabricated using organic-inorganic nanocomposite layers

Nanocomposite layers based on silica nanoparticles and a methacrylate matrix are synthesized by a solvent-free process and characterized in order to realize UV/Vis transparent optical waveguides. Chemical functionalization of the silica nanoparticles permits to interface the polymers and the silica. The refractive index, roughness and wettability and the machinability of the layers can be tuned changing the silica nanoparticle concentration and chemical modification of the surface of the nanoparticles. The optical transparency of the layers is affected by the nanoparticles organization between the organic chains, while it increased proportionally with respect to silica concentration. Nanocomposite layers with a concentration of 40 wt% in silica reached UV transparency for a wavelength of 250 nm. UV/Vis transparent waveguides were micromilled through nanocomposite layers and characterized. Propagation losses were measured to be around 1 dB cm(-1) at a wavelength of 350 nm.     

A software laboratory for visual inspection and recognition

We present the design criteria and the basic structure of GYPSY, a software laboratory for visual inspection and recognition in industrial automation tasks.GYPSY analyzes images of objects on the basis of their two-dimensional shape. It is fully portable and easily programmable. The user can write application programs in a Pascal-like language to give the system the ability to take over various tasks.GYPSY has been developed for a multi-microprocessor architecture designed in Italy especially for industrial automation.     

Theoretical developments in discrete-time control

Significant theoretical developments in discrete-time control over the past 10–15 years are reviewed. Topics reviewed include optimal control, Riccati equations, controllability, stability, robustness, deadbeat control, minimum-time systems, sampling, quantization, microprocessor implementation, and stochastic systems. Emphasis is placed on topics that are peculiar to discrete-time systems and do not generalize from continuous-time theory.     

Degradation of sulphur containing s-triazines during water chlorination

The reactions of four sulphur containing s-triazines (prometryne, terbutryne, ametryne and desmetryne) with hypochlorous acid (HClO) and chlorine dioxide (ClO₂) have been investigated using an 11 ppm/3 ppm oxidant/herbicide ratio. The main objective of the study was the identification of by-products. Additionally, to study the effect of oxidant concentration on the reaction rate, two more oxidant/herbicide ratios (3 ppm/3 ppb and 11 ppb/3 ppb) have been investigated only for prometryne. Oxidation reactions were monitored by high performance liquid chromatography (HPLC), while, the identification of by-products was initially carried out by low resolution HPLC-mass spectrometry (HPLC-MS) and confirmed by accurate mass measurement. Under the experimental conditions (T = 20°C, pH = 8, reaction TIME = 48 h), the results indicate that all the investigated triazines react in the same way with each oxidant. The reactions with HClO occur much faster than those with ClO₂ and give rise to three identified oxidation by-products: the sulfoxide, the sulfone and the sulfone's hydrolysis product. The reactions with ClO₂, instead, give rise to a sole oxidation by-product: the sulfoxide. With both oxidants, as expected, the lower the oxidant concentration the slower the oxidation rate.

Based on the obtained results, a general pathway for the oxidation of sulphur containing s-triazines is proposed.     

One-dimensional modelling of ‘verso’ laser cleaning

In this paper we present a one-dimensional model describing the verso laser cleaning technique, already experimentally tested, for particle removal from a substrate. The equation for displacement is treated for a one-dimensional case, and the temporal behaviour of the rear surface deformation is determined. Taking into account the van der Waals adhesion force and elastic deformation of a spherical particle (JKR model), the ejection condition has been obtained. Numerical values for an example are consistent with experimental observation.