Search results for " querce"
showing 10 items of 26 documents
Nano-hybrids based on quercetin and carbon nanotubes with excellent anti-oxidant activity
2016
Abstract Multi-functional nano-hybrids based on Quercetin (Q), a natural antioxidant, and functionalized Carbon Nanotubes (CNTs) have been formulated and used to prepare Ultra High Molecular Weight PolyEthylene (UHMWPE)-based nanocomposites. The study of the nanocomposites rheological behaviour shows that the immobilization of Q molecules onto CNTs outer surface leads to a beneficial effect on the state of the interface between polymer and nanoparticles. Additionally, the investigation of the thermo- and photo-oxidation processes reveals that the hybrids nanoparticles are able to exert a remarkable stabilizing action, due to strong physical interaction between Q and CNTs. In particular, the…
Thermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes
2015
Abstract Quercetin (Q), a natural antioxidant molecule, is physically immobilized onto multi-walled carbon nanotubes (CNTs) bearing covalently-linked long-chain alkyl functional groups, and the so obtained hybrid-nanoparticles are used to prepare Ultra High Molecular Weight PolyEthylene-based nanocomposite films with enhanced thermo-oxidation resistance. The effective immobilization of the Q molecules is confirmed by spectroscopic (micro-Raman, ATR-FTIR, and FTIR) and thermo-gravimetric analyses, and the influence of the nanoparticles on the rheological behaviour and thermo-oxidative stability of the nanocomposites are investigated. Rheological analyses (linear viscoelasticity and stress re…
A test on Ellenberg indicator values in the Mediterranean evergreen woods (Quercetea ilicis)
2015
The consistency and reliability of Ellenberg’s indicator values (Eiv) as ecological descriptors of the Mediterranean evergreen vegetation ascribed to the phytosociological class Quercetea ilicis have been checked on a set of 859 phytosociological releves × 699 species. Diagnostic species were identified through a Twinspan analysis and their Eiv analyzed and related to the following independent variables: (1) annual mean temperatures, (2) annual rainfall. The results provided interesting insights to disentangle the current syntaxonomical framework at the alliance level demonstrating the usefulness of ecological indicator values to test the efficiency and predictivity of the phytosociological…
Indagini conoscitive su popolamenti forestali di roverella (Quercus pubescens Willd. s.l.) con potenziali caratteri di vetustà
2022
Gli ecosistemi forestali, che attraversano un lungo periodo senza rilevanti azioni di disturbo antropico quali le utilizzazioni forestali, possono evolvere con caratteristiche compositive e strutturali che li distinguono nettamente da soprassuoli più giovani dello stesso tipo, e sotto particolari condizioni vengono definiti vetusti. La significativa presenza di piante adulte e grandi, una certa diversificazione strutturale, significativi quantitativi di legno morto sia in piedi che a terra e la presenza di fauna e flora specializzate, sono tra le caratteristiche più comunemente associate ai boschi vetusti. A livello italiano, con le modifiche apportate al Testo Unico Forestale (D.Lgs. 34 de…
La classe Quercetea ilicis in Sicilia.
2008
On the basis of literature data and numerous unpublished relevès, a syntaxonomic revision of Quercetea ilicis class in Sicily is given. The surveyed associations are represented by evergreen, deciduous o mixed plant communities forming shrubland, maquis, bushland and woodland. They are communities dominated by sclerophylls or deciduous trees, widespread from the shoreline up to 1400 (1600) m of altitude, within the bioclimatic belts between the inframediterranean dry lower one and the mesomediterranean subhumid-humid one, extending to the supramediterranean belt. The study, regarding all the Sicilian territory including the neighboring islets, was carried out through the elaboration of syno…
Phytosociological study of the acidophilous deciduous oak woods with Ilex aquifolium of Sicily
2009
We present here a phytosociological study with ecological considerations of some formations with a prevalence of Quercus pubescens s.l. and Ilex aquifolium that occur on siliceous ground in the Madonie and Peloritani Mountains of Sicily. On the basis of this study, these formations have been attributed to two new associations: Ilici aquifolii-Quercetum leptobalani and Conopodio capillifolii-Quercetum congestae, within the order Quercetalia pubescenti- petraeae, which is already represented by other associations in Sicily.
The order Quercetalia virgilianae: a new proposal for the classification of semi-deciduous forests in the Mediterranean and sub-Mediterranean area.
2017
The semi-deciduous oaks belonging to Quercus pubescens s.l. group (Q. congesta C. Presl, Q. virgiliana (Ten.) Ten., Q. dalechampii Ten., Q. amplifolia Guss. and Q. leptobalanus Guss.) are widespread in the Italian Peninsula, Sicily, Sardinia and along the southern coasts of the Balkan peninsula and more generally in the whole Mediterranean area, especially in the transition zone between the temperate and Mediterranean macrobioclimate identified by the sub-mediterranean variant (Brullo et al., 1999). These forests are currently expanding rapidly because of the decreased anthropic exploitation. The syntaxonomic classification of these forest typologies is quite critical, because their florist…
Solubility of Quercetin in Wines
2022
Quercetin solubility at 18 °C and 0 °C was determined in an hydroalcoholic buffer solution with pH 3.20 and in four Italian wines to study the formation of quercetin precipitate mechanism in wines. The wines selected were Barbera 2018 for the typically high content in bisulfite bleachable pigments, red Cirò 2014, for its typically high content of flavonoids, Sangiovese 2014, for the presence of quercetin deposits in bottle, and white Cirò 2018, for the absence of red pigments. All the samples were spiked with 30 mg/L quercetin. The amount of quercetin solubilized at 18 °C and 0 °C in the hydroalcoholic buffer was much lower than in wines, while that solubilised in Barbera was much higher co…
Immobilization of natural anti-oxidants on carbon nanotubes and aging behavior of ultra-high molecular weight polyethylene-based nanocomposites
2014
The use of natural antioxidants is an attractive way to formulate nanocomposites with extended durability and with potential applications in bio-medical field. In this work, Vitamin E (VE) in the form of α-tocopherol and Quercetin (Q) are physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs). Afterward, the CNTs-VE and CNTs-Q are used to formulate thermally stable ultra high molecular weight polyethylene based nanocomposites. The obtained results in the study of the thermo-oxidation behavior suggest a beneficial effect of the natural anti-oxidant carbon nanotubes systems. The unexpected excellent thermo-resistance of the nanocomposites seems to be due to a syne…
Effect of leaf removal and ripening stage on the content of quercetin glycosides in Sangiovese grapes
2021
Quercetin haze has been observed over the last few years in some aged Sangiovese wines. This problem could be due to an excess of the quercetin in the wine. Leaf removal increases the exposition of clusters to sunlight, which may enhance flavonol synthesis in the grapes. In this study, we evaluated the dynamics related to extractable flavonols in grapes grown in three usually defoliated Vitis vinifera (L.) cv. Sangiovese vineyards, whose wines showed quercetin precipitates. The particular structure of the vineyards in which the leaf removal experiments were carried out allowed the influence of vineyard, biotype and rootstock on grape flavonol contents at mid-maturation and technological mat…