Effect of shape and surface chemistry of TiO2 colloidal nanocrystals on the organic vapor absorption capacity of TiO2/PMMA composite

The organic vapor absorption capacity of poly(methyl metacrylate) (PMMA), filled with oleic acid (OLEA) capped TiO₂ nanocrystals (NCs) with curved shape, rod-like and spherical, is studied. The NC shape combined with the nature of the capping molecules can be used to enhance or reduce the PMMA ability to absorb different solvent molecules in a controlled way. Indeed, the arrangement of the ligands at the NC surface demonstrates an effective tool to control the extent of the interaction between the penetrating molecules and the embedded NCs from the outer to the inner specific chemical functionality of the coordinating ligand molecules.     

Polyphenol content and antiradical activity of Cichorium intybus L. from biodynamic and conventional farming

Conventionally- and biodynamically-grown chicory (Cichorium intybus L.) was compared for its polyphenol content and antiradical activity. Two growing periods were analysed: in the first, the plants were subjected to severe water stress; in the second the stress was absent. The polyphenol content (Folin–Ciocalteu test) was higher in samples from the former than in the latter (about 650 and 420mg of gallic acid/100g fresh sample, respectively), and in any case did not differ between the two growing systems; antiradical activity for the second sampling was higher in the case of the biodynamic system. HPLC/DAD/MS analysis identified five hydroxycinnamic acids and eight flavonoids (quercetin, kaempferol, luteolin and apigenin glycosides) and indicated changes in hydroxycinnamic content in the four samplings which were greatest in the case of conventional farming. Biodynamic farming, like organic farming, allows the achievement of good results, with particular attention to environmental conditions.     

Comparison of different extraction and clean-up procedures for the determination of fumonisins in maize and maizebased food products

In order to optimize the analytical method for the determination of fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) in diVerent maize products, five materials (maize flour, cornflakes, extruded maize, muffins and infant formula) were investigated under a variety of experimental conditions organized in a ruggedness test according to a factorial design. The influence of five factors (extraction solvent, extraction mode, volume of extraction solvent, test sample size and clean-up) on method performances was tested by four laboratories using spiked materials (0.5 μg/g and 1.5 μg/g FB₁ + FB₂) and naturally contaminated materials (ca 1.5 μg/g with FB₁ + FB₂). The end determination step was performed by high-performance liquid chromatography analysis of the o-phthaldialdehyde derivatized extracts. The ruggedness test permitted identification of two critical factors in the analysis of fumonisins in the above products, namely 'extraction solvent' and 'cleanup procedure'. In particular, the use of acetonitrile (ACN)-water (1 + 1, v + v) as extraction solvent and immunoaffinity column for clean-up provided better recovery of fumonisins and chromatographic resolution as compared with methanol (MeOH)-water (3 + 1, v + v) and strong anion exchange (SAX), respectively. However, phase separation occurring after extraction with ACN-water may have given incorrect results. Based on the information obtained with the present study it was possible to develop a new method horizonhorizontally applicable to all the above mentioned maize-based food matrices.     

Simultaneous quantification of caffeoyl esters and flavonoids in wild and cultivated cardoon leaves

Cynara cardunculus is a diploid (2n = 2x = 34) species, native to the Mediterranean basin, which belongs to the family of Asteraceae. It includes globe artichoke, cultivated cardoon, as well as their progenitor wild cardoon. The species is a source of biophenols and its leaf extracts have been widely used in herbal medicine as hepatoprotectors and choleretics since ancient times. Globe artichoke leaves have been found to be rich in compounds originating from the metabolism of phenylpropanoids however, to our knowledge, the leaf polyphenolic composition of the two other forms within the species, cultivated and wild cardoon, have not yet been properly investigated. Two main classes of polyphenols have been detected by HPLC/DAD and HPLC/MS analyses: caffeoyl esters and flavonoids. The compounds which are the result of esterification of caffeoylquinic acid moiety with succinic acid, previously detected in other members of the Asteraceae family, were detected in cardoon leaves for the first time.     

Selection and use of autochthonous mixed starter for lactic acid fermentation of carrots, French beans or marrows

Strains of Leuconostoc mesenteroides, Lactobacillus plantarum, Weissella soli/Weissella koreensis, Enterococcus faecalis, Pediococcus pentosaceus and Lactobacillus fermentum were identified from raw carrots, French beans and marrows by partial 16S rRNA gene sequence. L. plantarum M1, Leuc. mesenteroides C1 and P. pentosaceus F4 were selected based on the rates of growth and acidification in vegetable juice media, and used as the autochthonous mixed starter for the fermentation of carrots, French beans or marrows. An allochthonous starter, consisting of the same species, was also used for fermentation. A two-step fermentation process (1 day at 25 degrees C and 7 days at 15 degrees C) in brine (1% w/v) followed by storage at room temperature in olive oil until 40 days was set up. Unstarted vegetables subjected to the same treatments were used as the controls. Cell numbers of lactic acid bacteria in the started vegetables were ca. 10,000 (autochthonous starter) and 1000 (allochthonous starter) times higher than unstarted samples throughout the process. When fermented with the autochthonous starter, carrots, French beans or marrows were characterized by the rapid decrease of pH (<4.5), marked consumption of fermentable carbohydrates, and inhibition of Enterobacteriaceae and yeasts. Fermentation with the allochthonous starter did not acidify and inhibit bacteria and yeasts so rapidly. After 40 days, carrots, French beans and marrows fermented with the autochthonous starter had significantly (P<0.05) higher total concentration of vitamin C (ascorbate+dehydroascorbate) with respect to those fermented with the allochthonous starter and, especially unstarted vegetables. The same was found for the indexes of color. Firmness of both started vegetables was higher than unstarted vegetables. Sensory analysis differentiated started vegetables. Carrots and French beans fermented with the autochthonous starter were, especially, appreciated for fragrance. Appearance was the sensory attribute that mainly distinguished marrows fermented with the autochthonous starter.     

Polyamines content in plant derived food: A comparison between soybean and Jerusalem artichoke

This paper aims to compare the dietary polyamine intake coming from foods derived from two different plants: soybean (Glycine max L.) well known and universally utilised both fresh and processed, and Jerusalem artichoke (Helianthus tuberosus L.) tuber, not yet well known and scarcely utilised in the everyday diet. Free, soluble and insoluble conjugated polyamines were determined in different soy-derived foodstuffs such as milk, tofu and fermented soy sauce, and in soybeans coming from two different organic experimental fields (Imola and Altedo, Bologna, Italy). Results show that free polyamines (in particular putrescine and spermidine) were present in relevant amounts especially in tofu and soy sauce. Conversely, the Helianthus parenchymatous medulla tissue, which is the only edible part of the tuber, contains very low levels of polyamines, which are instead preferentially accumulated in the buds. These data could suggest a preferential utilisation of Helianthus tuber in the diet of people with special needs, such as patients treated by chemotherapy and patients with diabetes.     

Proteolytic and lipolytic starter cultures and their effect on traditional fermented sausages ripening and sensory traits

In this study, three starter formulations including Lactobacillus curvatus and Staphylococcus xylosus strains selected in vitro on the basis of their lipolytic and proteolytic activities were employed for the manufacture of traditional fermented sausages of southern Italy. Microbial population, proteolysis, lipolysis, changes in free amino acids (FAA) and free fatty acids (FFA) and development of characteristic taste and flavor of the final product were investigated. Proteolysis and lipolysis were observed in sausages inoculated with proteolytic and lipolytic S. xylosus coupled with L. curvatus, while the sausage started with only S. xylosus without lactobacilli was identical to the non-inoculated control, indicating that the proteolysis could be due to both microbial activity and endogenous proteases activated by the decrease in pH. The statistical analysis applied to the instrumental and sensory data showed that there was an effect of the starter used on the characteristics of the sausage obtained. In particular, the control samples showed very close features different from the sausages obtained by adding starter cultures. Finally, analyzing the sensory parameters the sausages ripened without starter addition and those started without the L. curvatus AVL3 showed similar features indicating an influence of the presence of the lactobacilli on the final organoleptic quality of the sausages. An appropriate choice of a combination of strains in a starter formulation is fundamental to obtain products of the expected quality.     

Antimicrobial susceptibility of vancomycin-susceptible and -resistant enterococci isolated in Italy from raw meat products, farm animals, and human infections

The susceptibility of vancomycin-resistant (VRE) and vancomycin-susceptible (VSE) enterococci to 10 antimicrobial agents was evaluated. The strains, belonging to different species, were isolated in Italy from raw meat products, farm animals, and human clinical infections in the years 1997-2000. High frequency of resistance to tetracycline and erythromycin was observed in all the groups of strains. On the contrary, chloramphenicol was the only drug that showed a relatively low rate of resistance in all the groups examined. In general, the resistance rates observed for VSE did not differ from those observed for VRE of the same species and origin. Some differences could be noticed among the different enterococcal species, with Enterococcus faecium strains being usually more resistant to beta-lactams, and Enterococcus faecalis strains more resistant to gentamicin. However, the strongest differences were observed when the strains were compared according to their source, the human isolates being usually more resistant than the isolates of animal origin. No significant difference was observed between isolates of swine and poultry origin. Among VRE E. faecium, multiple resistance was much more frequent among the human strains (90%) than among poultry (48.9%) and swine (26.5%) strains. These results show that in Italy VRE isolates from human clinical infections are usually more resistant than isolates from meat products and farm animals, and possess different antimicrobial resistance profiles.     

Scanning tunnelling microscopy investigations of self-assembled monolayers of poly(3-decyl-thiophene) on graphite

The self-assembly technique experimented for the deposition of alkanes and alkyl derivatives on layered compounds at the liquid/solid interface has been successfully extended to the adsorption of poly(3-decyl-thiophene) on graphite. The molecular films so obtained have been investigated using scanning tunnelling microscopy (STM). Images taken in both the constant-current and constant-height modes show highly packed arrays of molecules characterised by an average length and an average spacing that are in good agreement with results obtained by X-ray diffraction investigations. Constant-current images allow one to observe domain formations in preferential directions coincident with the main axes of the graphite lattice, while constant-height imaging, performed on small areas, allows one to resolve atomic structures within the polymer backbone. In particular, periodic, 0.71 nm spaced features have been identified along the side of the polymer backbone; they can be associated with the length of two monomer units and are attributable to imaging of sulphur atoms in the backbone.     

Coupling of quantum angular momenta: an insight into analogic/discrete and local/global models of computation

In the past few years there has been a tumultuous activity aimed at introducing novel conceptual schemes for quantum computing. The approach proposed in (Marzuoli and Rasetti, 2002, 2005a) relies on the (re)coupling theory of SU(2) angular momenta and can be viewed as a generalization to arbitrary values of the spin variables of the usual quantum-circuit model based on ‘qubits’ and Boolean gates. Computational states belong to finite-dimensional Hilbert spaces labelled by both discrete and continuous parameters, and unitary gates may depend on quantum numbers ranging over finite sets of values as well as continuous (angular) variables. Such a framework is an ideal playground to discuss discrete (digital) and analogic computational processes, together with their relationships occurring when a consistent semiclassical limit takes place on discrete quantum gates. When working with purely discrete unitary gates, the simulator is naturally modelled as families of quantum finite states-machines which in turn represent discrete versions of topological quantum computation models. We argue that our model embodies a sort of unifying paradigm for computing inspired by Nature and, even more ambitiously, a universal setting in which suitably encoded quantum symbolic manipulations of combinatorial, topological and algebraic problems might find their ‘natural’ computational reference model.