Glass powders and reactive silicone binder: Interactions and application to additive manufacturing of bioactive glass-ceramic scaffolds

A novel concept for the additive manufacturing of three-dimensional glass-ceramic scaffolds, to be used for tissue engineering applications, was based on fine glass powders mixed with a reactive binder, in the form of a commercial silicone. The powders consisted of ‘silica-defective glass’ specifically designed to react, upon firing in air, with the amorphous silica yielded by the binder. By silica incorporation, the glass was intended to reach the composition of an already known CaONa2OB2O3SiO2 system. Silica from the binder provided up to 15 wt% of the total silica. With the same overall formulation, silicone-glass powder mixtures led to nearly the same phase assemblage formed by the reference system, crystallizing into wollastonite (CaSiO3) and Ca-borate (CaB2O4). Samples from silicone-glass powder mixtures exhibited an excellent shape retention after firing, which was later exploited in highly porous reticulated scaffolds, obtained by means of direct ink writing (DIW)

Meningococci of serogroup X clonal complex 181 in refugee camps, Italy

Four cases of infection with serogroup X meningococci (MenX) (1 in 2015 and 3 in 2016) occurred in migrants living in refugee camps or reception centers in Italy. All MenX isolates were identified as clonal complex 181. Our report suggests that serogroup X represents an emerging health threat for persons arriving from African countries

Glass-ceramic foams and reticulated scaffolds by sinter-crystallization of a hardystonite glass

In the present investigation, we focused on a glass-based route to hardystonite ceramics, which represent one of the most promising classes of biomaterials, in the form of highly porous scaffolds. A glass corresponding to the stoichiometry of a hardystonite solid solution (Ca2Zn0.85Mg0.15Si2O7) was first synthesized and reduced in the form of fine powders (70 vol%), obtained by direct foaming or stereolithography of specifically formulated suspensions. More precisely, foams were obtained by intensive mechanical stirring (with the help of a surfactant) of suspensions undergoing gelation, in weakly alkaline aqueous solutions. Reticulated structures with complex non-stochastic geometry, on the other hand, were obtained by digital light processing of glass powders suspended in a photosensitive organic binder. The intensive crystallization caused an excellent retention of the shapes generated at room temperature. The uniform microstructures, all comprising quite dense struts, favored the mechanical properties (with crushing strength well exceeding 2 MPa, with open porosity above 65 vol%)

Particulate Shiga Toxin 2 in Blood is Associated to the Development of Hemolytic Uremic Syndrome in Children

Hemolytic uremic syndrome (HUS), the leading cause of acute renal failure in children (< 3 years), is mainly related to Shiga toxins (Stx)-producing Escherichia coli (STEC) infections. STEC are confined to the gut resulting in hemorrhagic colitis, whereas Stx are delivered in blood to target kidney and brain, with unclear mechanisms, triggering HUS in 5 to 15% of infected children. Stx were found on circulating cells, free in sera (soluble Stx) or in blood cell-derived microvesicles (particulate Stx), whereby the relationship between these forms of circulating toxins is unclear. Here, we have examined 2,846 children with bloody diarrhea and found evidence of STEC infection in 5%. Twenty patients were enrolled to study the natural course of STEC infections before the onset of HUS. In patients, Stx were found to be associated to circulating cells and/or free and functionally active in sera. In most children, Stx were bound to neutrophils when high amounts of toxins were found in feces. Time-course analysis showed that Stx increased transiently in patients' sera while the decrease of toxin amount on leukocytes was observed. Notably, patients who recovered (85%) displayed different settings than those who developed HUS (15%). The distinctive feature of the latter group was the presence in blood of particulate Stx2 (Stx2 sedimented at g -forces corresponding to 1 \u3bcm microvesicles) the day before diagnosis of HUS, during the release phase of toxins from circulating cells. This observation strongly suggests the involvement of blood cell-derived particulate Stx2 in the transition from hemorrhagic colitis to HUS