Moisture behaviour and biological durability of wood‐polymer composites

In recent years wood-polymer composites appears at the European market more frequently, mainly in decking applications as an alternative for durable tropical hardwood decking. This study focuses on extruded decking products based on polypropylene (PP), polyethylene (PE) or polyvinylchloride (PVC) and wood flour. All products are commercially available on the Belgian market. Initially WPC’s were said to be resistant for biological degradation as the wood particles should be encapsulated by the polymer, but over the years several cases of fungal decay of WPC have been reported. Therefore the moisture behaviour of the different WPC decking materials was first assessed by various moistening methods to determine if the moisture content can reach levels that initiate fungal growth. Concerning this, WPC shows better results than the traditional wood composites like particle board, MDF or OSB, but clearly absorbs sufficient moisture to be critical if sorption time is long enough. Therefore, when biological durability is tested, an adequate standard, more specific for WPC products, is needed in stead of just copying the standards designed for wooden panel products. For WPC materials a moistening pre-treatment is needed prior to the proper fungal test to include moistening time as a critical factor for assessing biological durability of these materials. Furthermore placing the products in a fungal control unit that evaluates the susceptibility for airborne surface stains revealed different results and showed that fungi grew earlier and faster on weathered samples. Concluding, in spite of the different composition of the tested products, no product was significantly better or worse than the other concerning the moisture behaviour. Furthermore only a few products were to a small extent covered by moulds in the fungal control unit

The Tri-National Prespa Park in Albania, Greece and Macedonia (FYROM): Using Environment to Define the New Boundaries of the European Union

International audienceThis paper is based on a study of the natural park created in 2000 on the territory of Albania, Greece and Macedonia (FYROM). Since then, the Prespa Park has always been presented as a successful model of cross-border cooperation in a region characterized at that time by its high level of instability. The creation of the park appeared both as a possibility to test re-drawn neighbours' relationships as well as rural and environmental management in a remote and problematic border zone of the European Union. A dialectic relation links those two aspects and needs to be analysed. On one hand, in the context of the reduction of support aid brought on by the Common Agricultural Policy in an enlarged union, the EU's local development programmes based on environmental management may be simply a lesser evil. On the other hand, the EU integration process is a high stake issue for national authorities, and the Prespa Park may be considered as a first step toward a more efficient use of EU tools in rural matters. The meeting of stakeholders of different levels around a negotiation table in order to give life to a cross-border natural park is one thing. The revitalisation of a common territory torn to pieces is something else. Does the formal recognition of a common natural heritage make sense in social, economic and politic life on the borders

Machine learning of molecular motifs in soft supramolecular systems

L'abstract è presente nell'allegato / the abstract is in the attachmen

Release of VEGF from dental implant improves osteogenetic process: Preliminary in vitro tests

INTRODUCTION: During osseointegration process, the presence of an inflammatory event could negatively influence the proper osteogenetic ability of the implant surface. In order to reduce this possibility, an implementation of angiogenetic event through the release of Vascular Endothelial Growth Factor (VEGF) can be a tool as co-factor for osteoblastic differentiation. In this paper, novel dental implant surfaces enriched with VEGF have been tested. MATERIAL AND METHODS: The ability of VEGF-enriched titanium implants to improve the osteogenetic properties of Mesenchymal stem cells (MSC), also in the presence of an inflammatory environment, have been in vitro tested. Molecular biology, morphological analyses, and biochemical tests have been performed in order to confirm biological properties of these surfaces. RESULTS: Our results confirm that the presence of VEGF onto the implant surface is able not only to protect the cells from in vitro aging and from Reactive Oxygen Species (ROS) damage, but it also improves their osteogenic and endothelial differentiation, even in the presence of inflammatory cytokines. CONCLUSION: This study establishes a biologically powerful novel tool that could enhance bone repair in dental implant integration

La inteligencia artificial en arqueología: hoy y mañana

Sin resume

Development of plate-based sialic acid assays to support clone screening and early Stage upstream process development

Sialic acid, a post-translational modification, is an important product quality attribute of glycoproteins. The levels of sialic acid may impact solubility of the final product and the half-life (product clearance). In addition, the N-glycolylneuraminic acid (NGNA) form of sialic acid may elicit an immunogenic response in humans. In an effort to have a more high-throughput evaluation of these product quality attributes, two plate based assays were developed. Specifically, a direct NGNA ELISA was developed using a polyclonal chicken anti-NGNA antibody. This assay was implemented as one of the clone screening tools to eliminate clones that may produce more of the immunogenic sialic acid. In addition, the assay was developed using both purified materials and harvest cell culture fluid (HCCF), thereby eliminating the need for downstream processing and enabling high-throughput of samples. The results of the assay were verified using the more traditional Dionex method. The second assay developed was a fluorescence based plate assay to measure total sialic acid levels on our protein of interest. During early stage process development, different culture conditions resulted in varying levels of total sialic acid on the final product. This assay was used to monitor the impact of changes in media/feed components and operation parameters on total sialic acid levels. Although results of this plate based assay from purified material gave the same ranking as those from the Dionex method, assays performed with HCCF gave much higher background values. Therefore, a high-throughput resin plate method of purification to provide suitable and representative samples was established. The purity of these one step purified materials were \u3e 80% and the assay results were in line with the traditional methods. Using both of the assays developed ensured we established a cell line and upstream process that produced a protein with the desired quality of sialic acid content, while minimizing the potentially immunogenic NGNA

Porcine bone scaffolds adsorb growth factors secreted by MSCs and improve bone tissue repair

An ideal tissue-engineered bone graft should have both excellent pro-osteogenesis and pro-angiogenesis properties to rapidly realize the bone regeneration in vivo . To meet this goal, in this work a porcine bone scaffold was successfully used as a Trojan horse to store growth factors produced by mesenchymal stem cells (MSCs). This new scaffold showed a time-dependent release of bioactive growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in vitro . The biological effect of the growth factors-adsorbed scaffold on the in vitro commitment of MSCs into osteogenic and endothelial cell phenotypes has been evaluated. In addition, we have investigated the activity of growth factor-impregnated granules in the repair of critical-size defects in rat calvaria by means of histological, immunohistochemical, and molecular biology analyses. Based on the results of our work bone tissue formation and markers for bone and vascularization were significantly increased by the growth factor-enriched bone granules after implantation. This suggests that the controlled release of active growth factors from porcine bone granules can enhance and promote bone regeneratio

Bioactive glass-ceramic scaffolds from novel 'inorganic gel casting' and sinter-crystallization

Highly porous wollastonite-diopside glass-ceramics have been successfully obtained by a new gel-casting technique. The gelation of an aqueous slurry of glass powders was not achieved according to the polymerization of an organic monomer, but as the result of alkali activation. The alkali activation of a Ca-Mg silicate glass (with a composition close to 50 mol % wollastonite50 mol % diopside, with minor amounts of Na2O and P2O5) allowed for the obtainment of well-dispersed concentrated suspensions, undergoing progressive hardening by curing at low temperature (40 degrees C), owing to the formation of a C-S-H (calcium silicate hydrate) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. The open-celled structure resulting from mechanical foaming could be frozen' by the subsequent sintering treatment, at 900-1000 degrees C, causing substantial crystallization. A total porosity exceeding 80%, comprising both well-interconnected macro-pores and micro-pores on cell walls, was accompanied by an excellent compressive strength, even above 5 MPa