Using organoclay to promote morphology refinement and co-continuity in high-density polyethylene/polyamide 6 blends - Effect of filler content and polymer matrix composition

We investigate the gradual changes of the microstructure of two blends of high-density polyethylene (HOPE) and polyamide 6 (PA6) at opposite composition filled with increasing amounts of an organo-modified clay. The filler locates preferentially inside the polyamide phase, bringing about radical alterations in the micron-scale arrangement of the polymer phases. When the host polyamide represents the major constituent, a sudden reduction of the average sizes of the polyethylene droplets was observed upon addition of even low amounts of organoclay. A morphology refinement was also noticed at low filler contents when the particles distributes inside the minor phase. In this case, however, keep increasing the organoclay content eventually results in a high degree of PA6 phase continuity. Rheological analyses reveal that the filler loading at which the polyamide assembles in a continuous network corresponds to the critical threshold for its rheological transition from a liquid- to a gel-like behaviour, which is indicative of the structuring of the filler inside the host PA6. On the basis of this finding, a schematic mechanism is proposed in which the role of the filler in driving the space arrangement of the polymer phases is discussed. Finally, we show that the synergism between the reinforcing action of the filler and its ability to affect the blend microstructure can be exploited in order to enhance relevant technological properties of the materials, such as their high temperature structural integrit

A Green Approach for Recycling Compact Discs

Compact discs (CDs) and digital versatile discs (DVDs) are mainly made by polycarbonate disc, a thin layer of aluminum or silver, a thin layer of a coating and a thin layer of a label of paper or PET. The recycling of these discs is difficult due to the removal of these non-polymeric layers and to our best knowledge, no industrial plants have been resent for their recycling. In this work, we propose a facile way to remove the non-polymeric layers and investigate the effect of the repetitive extrusion process on the processability and on the mechanical properties of the recycled polycarbonate. A few works have been published dealing with both the removal of the non-polymeric layers and the mechanical recycling of the disk of polycarbonate. In our approach, the removal of the non-polymeric layers is easily obtained through a thermo-mechanical treatment in a basic solution by ammonia. This process can be considered green because is made at a low temperature with a small amount of water and a very small amount of ammonia, saving energy and water. The properties of the polycarbonate remain good if the mechanical recycling is made after drying the post-consumer polycarbonate

Mechanical and thermal properties of insulating sustainable mortars with ampelodesmos mauritanicus and pennisetum setaceum plants as aggregates

The use of natural fibers in cement composites is a widening research field as their application can enhance the mechanical and thermal behavior of cement mortars and limit their carbon footprint. In this paper, two different wild grasses, i.e., Ampelodesmos mauritanicus, also called diss, and Pennisetum setaceum, also known as crimson fountaingrass, are used as a source of natural aggregates for cement mortars. The main purpose is to assess the possibility of using the more invasive crimson fountaingrass in place of diss in cement-based vegetable concrete. The two plant fibers have been characterized by means of scanning electron microscopy (SEM), helium picnometry and thermogravimetric analysis. Moreover, the thermal conductivity of fiber panels has been measured. Mortars samples have been prepared using untreated, boiled and Polyethylene glycol 4000 (PEG) treated fibers. The mechanical characterization has been performed by means of three point bending and compression tests. Thermal conductivity and porosity have been measured to characterize physical modification induced by fibers’ treatments. The results showed better thermal and mechanical properties of diss fiber composites than fountaingrass one and that fiber treatments lead to a reduction of the thermal insulation propertie

Gli uccelli delle isole circumsiciliane

Gli autori sintetizzano tutte le informazioni bibliografiche e inedite sulle specie che sino al 30 agosto 2015 sono state contattate almeno una volta nelle 14 isole circumsiciliane (Eolie, Ustica, Egadi, Pantelleria e Pelagie), confrontando alla fine la lista complessiva con quella delle isole Maltesi. In totale sono ad oggi note 434 specie (isole Maltesi incluse); molte di esse hanno mostrato nel corso dei secoli una notevole capacità di colonizzazione, fluttuando nel tempo o addirittura estinguendosi e ricolonizzando alcune isole. Questi piccoli territori in mezzo al mare rappresentano ottimi siti di controllo dell’andamento delle migrazioni nel corso dei decenni; alcune specie hanno chiaramente cambiato il loro status rispetto al passato, aumentando o diminuendo. Nel corso di circa 15 anni in alcune di queste isole (Ustica, Marettimo, Lampedusa e Linosa) sono stati condotti dei campi di inanellamento sia primaverili sia autunnali che hanno permesso di inanellare 102.208 uccelli, in gran parte Passeriformes; ciò ha consentito di raccogliere una notevole mole di dati sulle strategie migratorie, che vengono qui brevemente presentati. Le piccole isole sono davvero importanti per gli uccelli migratori transahariani, che devono sostare durante i loro lunghi viaggi per recuperare energie; la disponibilità di risorse sotto forma di frutti selvatici o di insetti (a seconda delle specie) consente a queste masse di migratori di continuare il loro viaggio. La conservazione degli uccelli è dettata dalla Direttiva Uccelli e l’istituzione delle Zone di Protezione Speciale ha proprio lo scopo di salvaguardare alcune specie in determinati territori. Questo è un impegno preso da parte di tutti i Paesi dell’Unione Europea, proprio perché le popolazioni di uccelli non conoscono confini amministrativi e la loro tutela va al di là delle competenze e degli interessi di un singolo Paese. Per quanto riguarda le specie nidificanti, è risultata un’elevata correlazione negativa (r=-0,746), altamente significativa (P=0,002) tra la capacità dispersiva media delle specie e la superficie in km2 delle isole. Le specie con minore capacità dispersiva hanno colonizzato le isole di maggiori dimensioni, ma non quelle più piccole; questo con molta probabilità dipende dalla eterogeneità ambientale, a sua volta legata alla dimensione delle isole ed alla loro posizione geografica. Nel caso delle isole circumsiciliane, sembra che non sia tanto la distanza dalla costa a determinare il numero di specie, quanto le condizioni ambientali e la posizione geografica; indubbiamente la posizione tirrenica delle isole settentrionali rappresenta un vantaggio per la presenza di habitat differenziati e la conseguente colonizzazione di specie ad essi legate, mentre la posizione meridionale, influenzata dall’aridità africana, riduce alcune possibilità colonizzatrici da parte di alcune specie di uccelli e rende altresì problematica la stessa esistenza di habitat diversificati. Il numero delle specie nidificanti in un’isola è variabile nel tempo, essendovi specie che vi nidificano in modo irregolare. La correlazione area/N° specie nelle isole circumsiciliane è pari a 0,58, ma se si esclude l’isola di Pantelleria, sale a 0,86; essa è pari a 0,92 per le sole isole settentrionali (Eolie, Ustica ed Egadi), mentre risulta 0,99 per le sole tre isole meridionali del Canale di Sicilia.Authors summarize all bibliographic and unpublished information on bird species that have been detected at least one time up to 30th August 2015 in the 14 circum-sicilian islands (Eolian, Ustica, Egadi, Pantelleria and Pelagian Is.). The Appendix 1 compares overall lists with that of the Maltese Is., also lying in the Sicilian waters. On the whole, 434 species are known till now (Maltese Is. included); many of them showed a high colonizing capacity along the centuries, fluctuating or even becoming extinct and re-colonising some islands. These small territories in the middle of the Mediterranean sea are very good check-control sites of long-term migration trend; compared to the past, some species changed their status, increasing or declining. Additionally, during the last 15 years in some of these islands (Ustica, Marettimo, Lampedusa and Linosa) bird ringing activity has been carried out, both in spring and in autumn; it allowed to ring 102,208 birds, mainly Passeriformes; this opportunity allowed to collect a remarkable amount of data on migration strategy, here presented. The small islands are very important stop-over sites for transsaharan migratory birds, that must rest during their long journey to recover fuel in the form of fat; the availability of natural resources, such as wild fruits or insects, allows these masses of migrant birds to continue their trip. The conservation of birds has been established by the Bird Directive and the institution of Zones of Special Protection has the aim to safeguard some species in some territories. This agreement was signed by all countries of the EU, because bird populations do not know administrative borders and their conservation lies beyond the interests and authorities of a single country. Concerning breeding birds, a high negative correlation (r=-0.746, P=0.002) has been found between the average dispersal power of species and the area in km2 of islands. Species with minor dispersal power colonized the biggest but not the smallest islands; this, very probably depended on habitat heterogeneity of islands, in turn linked to the size of them and to the geographical position, more than to the distance from the continental land. Tyrrhenian position of northern islands is certainly an advantage for the presence of diversified habitats and birds inhabiting them, whereas southern position of Pantelleria and Pelagian Is., as well as Maltese Is., affected by African dryness, decreases colonizing probabilities of some bird species and the same existence of diversified habitats. The number of breeding species in each island varied along the time and some species bred irregularly. The correlation area/No. species in the islands surrounding Sicily resulted to be 0.58, but if we exclude Pantelleria Is., it grows to 0.86; besides, it grows to 0.92 if we consider only northern islands (Eolian, Ustica and Egadi Is.), and to 0.99 if we consider only southern islands

Isolation of Vascular Wall Mesenchymal Stem Cells from the Thoracic Aorta of Adult Göttingen Minipigs: A New Protocol for the Simultaneous Endothelial Cell Collection

Simple Summary It has been widely demonstrated that blood vessels are sources of multipotent progenitor cells, including mesenchymal stem cells. These stem cellular populations persist throughout adulthood and can be isolated from both microvascular and large vessels. Increasing evidence suggests that vascular stem cells, together with other cell populations residing in blood vessels, such as endothelial cells, are involved in physiological and pathological vascular remodeling. In the present paper, we described, for the first time, a new improved method to isolate a pure population of vascular wall cells showing a preserved mesenchymal tri-lineage differentiative potential from thoracic aorta of Gottingen Minipigs, preserving and also collecting endothelial cells. Considering the increasing interest in the use of Gottingen Minipigs as an animal model for cardiovascular diseases, the results obtained in the present research open the way to plan in vitro vascular remodeling experiments by using in co-culture system vascular mesenchymal stem cells and endothelial cells.Two main classes of perivascular multipotent populations have been described: the microvascular pericytes and the vascular wall mesenchymal stem cells (VW-MSCs). VW-MSCs are isolated from large vessels in many species and they participate in vascular remodeling together with other cellular components such as endothelial cells. Considering that the Gottingen Minipigs are widely used in Europe as a translational model in the field of cardiovascular diseases, the aim of the present research was to isolate VW-MSCs from the adult aorta of Gottingen Minipigs while preserving and also collecting endothelial cells. The results obtained in the present research demonstrated that this new protocol allows us to obtain a pure population of VW-MSCs and endothelial cells. VW-MSCs from Gottingen Minipigs responded fully to the MSC minima international criteria, being positive to CD105, CD90, and CD44 and negative to CD45 and CD34. Moreover, VW-MSCs presented a differentiative potential towards osteogenic, chondrogenic, and adipogenic lineages. Overall, the present protocol, preserving the viability and phenotypic features of the two isolated populations, opens future possibilities of using minipig VW-MSCs and endothelial cells in in vitro vascular remodeling studies

Mediterranean Crossbills Loxia curvirostra sensu lato (Aves, Passeriformes): new data and directions for future research

Mediterranean Crossbills are as much differentiated as L. scotica and L. pytyopsittacus. They are sedentary, linked to pine trees and have evolved a thicker bill to extract the seeds from Pine cones. Their decolorization could be due to dietary causes. The authors studied biometrics, breeding phenology, and primary food of Italian popula tions living in Calabria and Etna (Sicily) and compared them with the other Mediterranean populations. A coevolutive radiation between the different populations of Mediterranean Crossbills presently living in the three main peninsulas, adiacent islands and North Africa occurred separately and this may be demonstrated by their morphometrics, their sedentariness, as well as by songs and some genetic results recently published. They conclude that the same criteria followed to raise L. curvirostra scotica to the species rank as scotica occur also for the dif ferent Mediterranean population

Strategies for the re-naturalization of reforestation: the case study of the Sicilian clay hills

Over the last decades many areas have been reforested along Europe, with great proportion been made with exotic species. Very often these reforestations do not evolve in more diverse configurations, where some kind of management can be necessary to try to enhance this evolution. The hole is a silvicultural technique consisting in open small gaps to create favourable conditions for the establishment of other species changing the former structure, microclimate and competitive conditions mirroring this natural processes that occurs in structured and mature forests. The best size of the hole seems to be around 500 m\ub2, as small holes may not change significantly the conditions and larger holes seems to favour degradation processes like soil erosion and loss of organic layers. The afforestaion of the Santa Ninfa Natural Reserve (Trapani Province, W-Sicily) were made using essentially Pinus spp. and Eucalyptus camaldulensis. Particularly, this last specie occur in high density monospecific forest structure covering 19 ha (8% of the reserve), where practically no kind of management has been made until now and very few natural regenerations is observed. The aim of the study was to verify the effectiveness of the restoration actions combining the hole technique and planting native species with different management levels