Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid): A mixture design study

Blends consisting of commercial poly(lactic acid) (PLA), poly(lactic acid) oligomer (OLA8) as plasticizer and a sulfonic salt of a phthalic ester and poly(D-lactic acid) as nucleating agents were prepared by melt extrusion, following a Mixture Design approach, in order to systematically study mechanical and thermal properties as a function of composition. The full investigation was carried out by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and tensile tests. The crystallization half-time was also studied at 105 °C as a function of the blends composition. A range of compositions in which the plasticizer and the nucleation agent minimized the crystallization half-time in a synergistic way was clearly identified thanks to the application of the Mixture Design approach. The results allowed also the identification of a composition range to maximize the crystallinity developed during the rapid cooling below glass transition temperature in injection moulding, thus allowing an easier processing of PLA based materials. Moreover the mechanical properties were discussed by correlating them to the chemical structural features and thermal behaviour of blends

Knock-Down of Cathepsin D Affects the Retinal Pigment Epithelium, Impairs Swim-Bladder Ontogenesis and Causes Premature Death in Zebrafish

The lysosomal aspartic protease Cathepsin D (CD) is ubiquitously expressed in eukaryotic organisms. CD activity is essential to accomplish the acid-dependent extensive or partial proteolysis of protein substrates within endosomal and lysosomal compartments therein delivered via endocytosis, phagocytosis or autophagocytosis. CD may also act at physiological pH on small-size substrates in the cytosol and in the extracellular milieu. Mouse and fruit fly CD knock-out models have highlighted the multi-pathophysiological roles of CD in tissue homeostasis and organ development. Here we report the first phenotypic description of the lack of CD expression during zebrafish (Danio rerio) development obtained by morpholino-mediated knock-down of CD mRNA. Since the un-fertilized eggs were shown to be supplied with maternal CD mRNA, only a morpholino targeting a sequence containing the starting ATG codon was effective. The main phenotypic alterations produced by CD knock-down in zebrafish were: 1. abnormal development of the eye and of retinal pigment epithelium; 2. absence of the swim-bladder; 3. skin hyper-pigmentation; 4. reduced growth and premature death. Rescue experiments confirmed the involvement of CD in the developmental processes leading to these phenotypic alterations. Our findings add to the list of CD functions in organ development and patho-physiology in vertebrates

Structure and luminescence properties of Dy2O3 doped bismuth-borate glasses

In this work heavy bismuth-borate glasses were studied as host matrices of Dy2O3 rare earth, for potential application as scintillator materials in high energy physics experiments and in general radiation detection systems. Glass matrices were prepared from 20BaO-xBi2O3-(80-x)B2O3 (x = 20, 30, 40 mol%) ternary systems and synthesized by the melt-quenching method at different temperatures in order to obtain high density and high transparency in the UV/Vis range. Particularly, the glass manifesting the higher transparency and with sufficiently high density was doped with Dy2O3 (2.5 and 5 mol%) in order to induce the luminescence characteristics. The effects of Bi2O3 and Dy2O3 on density, thermal behaviour, transmission as well as luminescence properties under UV excitation, were investigated. The experimental results show that the synthesized glasses can be considered promising candidate materials as dense scintillators, due to the Dy3 + centres emission

Lanthanum glass infiltrated alumina/alumina composites for dental prosthetic applications

Lanthanum glass frits suitable for infiltration in pre-sintered alumina were developed in order to obtain innovative alumina\u2013glass composites, which are promising materials for all-ceramic dental prosthetic restorations, such as single crowns and fixed partial dentures. Glass compositions belonging to the lanthanum-silicate-borate system were synthesized in order to reinforce and give an improved esthetic appearance to the pre-sintered Al2O3. Fifteen formulations, defined by using a mixture design approach, were melted and quenched in water at room temperature in order to obtain the frits. Those exhibiting the lower melting temperatures were tested for infiltration into Al2O3 to obtain Al2O3/glass composites. The frits and the composites were characterized by X-Ray diffraction, differential thermal analyses, hot stage microscopy, colorimetry (Hunter color scale) and scanning electron microscopy. The mechanical properties of the composites, in terms of flexure strength, were evaluated using a three-point bending tests

E-LCA of Two Microwave Absorbers Obtained from Slag of Copper Primary Production

Purpose: This research investigates the environmental performance of two products obtained using slag derived from copper primary production (copper slag, CS). The first is a tile produced as a traditional stoneware ceramic plate (CS tile) and the second product is a glass–ceramic sample obtained by melt quenching method (CS bulk sample). The products are intended for use in industrial plants as auxiliary heating elements aimed at absorbing microwave. Methods: The environmental assessment was carried out using LCA methodology, and the obtained outcomes were compared to the results calculated for a traditional tile containing silicon carbide (SiC tile). Results: The analyses show that the innovative products have an environmental load of 74% for the CS tile and 54% for the CS bulk sample lower than the environmental impact calculated for the traditional SiC-based material tile. The latter presents a high environmental load due to the incidence on the total impact of the raw materials production. In fact, LCA analysis proves that copper slag production has an impact of 96% lower with respect to the SiC production. Conclusions: This study identifies a possible waste reduction strategy in accordance with the European end-of-waste criteria, but these results should be supported by a site analysis in order to provide an appropriate context for decision making