DLP Fabrication of Zirconia Scaffolds Coated with HA/β-TCP Layer: Role of Scaffold Architecture on Mechanical and Biological Properties

In order to merge high-mechanical properties and suitable bioactivity in a single scaffold, zirconia porous structures are here coated with a hydroxyapatite layer. The digital light processing (DLP) technique is used to fabricate two types of scaffolds: simple lattice structures, with different sizes between struts (750, 900 and 1050 µm), and more complex trabecular ones, these latter designed to better mimic the bone structure. Mechanical tests performed on samples sintered at 1400 °C provided a linear trend with a decrease in the compressive strength by increasing the porosity amount, achieving compressive strengths ranging between 128-177 MPa for lattice scaffolds and 34 MPa for trabecular ones. Scaffolds were successfully coated by dipping the sintered samples in a hydroxyapatite (HA) alcoholic suspension, after optimizing the HA solid loading at 20 wt%. After calcination at 1300 °C, the coating layer, composed of a mixture of HA and beta-TCP (beta-TriCalcium Phospate) adhered well to the zirconia substrate. The coated samples showed a proper bioactivity, well pronounced after 14 days of immersion into simulated body fluid (SBF), with a more homogeneous apatite layer formation into the trabecular samples compared to the lattice ones

“L'IFRS 9 e il modello dell'expected credit loss: la convergenza tra regole contabili, regolamentazione prudenziale e risk management”

L'IFRS 9 e il modello dell'expected credit loss: la convergenza tra regole contabili, regolamentazione prudenziale e risk management

Analysis and regeneration strategies for the abandoned villages of the Santerno valley in Tuscany

[EN] The historical settlement system of the Mugello mountain in Tuscany is characterised by scattered rural stone villages and houses. In the past these villages housed communities mainly dedicated to the centuries-old cultivation of chestnut. The process of abandonment can be traced back between the 50s and 60s, when the inhabitants left these isolated places to head towards the cities in search of better economic and living conditions. This paper illustrates the research carried out on three abandoned settlements in the municipality of Firenzuola, with particular reference to the Santerno valley. Pratalecchia, Brento Sanico and Castiglioncello were taken as case studies to carry out a typological and constructive analysis, comprising conservation state and vulnerability maps of their vernacular heritage. The first part of the investigation analyzes the context and the environmental resources; identifies the characteristics of the recurring architectural types; and operates a classification of the building techniques. The main classes of stone-masonry types have been recorded. By applying the masonry quality index (IQM) method the mechanical parameters of the masonry types have been determined. In the second part of the research, the conservation state of the buildings have been assessed. According to a risk-based approach, a vulnerability level was determined for each building, considering the quality of the construction elements, the damage degree and the relation with adjacent buildings. The research allowed to outline a first methodological approach in order to plan future intervention priorities and to identify strategies for the sustainable conservation, enhancement and rehabilitation of this architectural heritage.Coppola, M.; Dipasquale, L.; Mannucci, L.; Rovero, L. (2022). Analysis and regeneration strategies for the abandoned villages of the Santerno valley in Tuscany. Editorial Universitat Politècnica de València. 1031-1038. https://doi.org/10.4995/HERITAGE2022.2022.149521031103

Impact of Congo Basin deforestation

The interactions between land cover change in Central Africa and the Africa monsoon is investigated using a regional climate model simulation (2000–2007) under a Congo Basin deforestation scenario. Decreased evaporation over the deforested area locally produces a heat low and reduced precipitation. In JJA, this low strengthens the West Africa monsoon causing increased precipitation over the Sahel and decreased precipitation over the Guinea coast. In DJF, it strengthens the south-equatorial African monsoon causing an increase of precipitation over south-equatorial Africa. Therefore our simulations indicate that the biosphere-state in Central Africa may play an important role locally but also remotely via interactions with regional monsoon dynamics. Copyright © 2012 Royal Meteorological Societ

A note on preconditioning weighted linear least squares, with consequences for weakly-constrained variational data assimilation

The effect of preconditioning linear weighted least-squares using an approximation of the model matrix is analyzed, showing the interplay of the eigenstructures of both the model and weighting matrices. A small example is given illustrating the resulting potential inefficiency of such preconditioners. Consequences of these results in the context of the weakly-constrained 4D-Var data assimilation problem are finally discussed.Comment: 10 pages, 2 figure

Computational issues in Optimization for Deep networks

The paper aims to investigate relevant computational issues of deep neural network architectures with an eye to the interaction between the optimization algorithm and the classification performance. In particular, we aim to analyze the behaviour of state-of-the-art optimization algorithms in relationship to their hyperparameters setting in order to detect robustness with respect to the choice of a certain starting point in ending on different local solutions. We conduct extensive computational experiments using nine open-source optimization algorithms to train deep Convolutional Neural Network architectures on an image multi-class classification task. Precisely, we consider several architectures by changing the number of layers and neurons per layer, in order to evaluate the impact of different width and depth structures on the computational optimization performance

The potential role of preventive and therapeutic immunonutrition strategies for pediatric food allergy: A mini-review

: Food allergy (FA) represents one of the main chronic conditions of the pediatric population. The gut microbiome (GM)-immune system axis is a milestone in affecting FA susceptibility. The dynamic and bidirectional crosstalk between the GM and immune system starts early in life, and it is deeply modulated during the first 1,000 days of life. Nutritional factors during this crucial period mainly influence the proper GM-immune system development and function across the lifespan, with potential beneficial or detrimental effects on health status. Immunonutrition strategies, applied from conception, could represent an innovative target for prevention and treatment of pediatric FA. Here we described the potential role of preventive and therapeutic immunonutrition strategies for pediatric FA, highlighting putative future perspectives in this field

Alkali activation of waste materials: sustainability and innovation in processing traditional ceramics

Environmental issues linked both to OPC production and waste management brought researchers to find new solutionsfor the production of more eco-efficient binders. In this frame, alkali-activated materials are receiving increasing attention. They are obtained by reaction of an alkali metal source, generally sodium or potassium, with amorphous calcium-aluminosilicate precursors. More recently, also the reuse of mining wastes was investigated due to the impressive production of sludges and muds which do not have practical applications and shall be landfilled. The aim of our researches was to investigate the use of semi-crystalline/high-crystalline by-products in the production of alkali-activated materials. Thus, two different powders were used: an alumino silicate mud, composed by quartz, feldspars, biotite and dolomite; and a carbonatic one, composed of calcite and small amounts of dolomite. Both powders were alkali-activated using a solution of NaOH and Na2SiO3. Pastes were produced mixing the activating solution and the powder in different liquid/solid ratiosandinvestigatingthe use of waste glass powder as further source of amorphous silica. Samples were oven-cured for 24h at 60-80 °C and then cured in different environments (dry, humid and immersed in water) for other 27 days before testing physical and mechanical properties. Very promising results were obtained in terms of compressive strength (about 30 MPa for the aluminosilicate sludge and up to 45 MPa for the carbonatic one), showing their potential as innovative building products

The role of probiotics and postbiotics in modulating the gut microbiome-immune system axis in the pediatric age

The complex microbial community of the gut microbiome plays a fundamental role in driving development and function of the human immune system. This phenomenon is named the gut microbiome-immune system axis. When operating optimally, this axis influences both innate and adaptive immunity, which orchestrates the maintenance of crucial elements of host-microorganisms symbiosis, in a dialogue that modulates responses in the most beneficial way. Growing evidence reveals some environmental factors which can positively and negatively modulate the gut microbiome-immune system axis with consequences on the body health status. Several conditions which increasingly affect the pediatric age, such as allergies, autoimmune and inflammatory disorders, arise from a failure of the gut microbiome-immune system axis. Prenatal or postnatal modulation of this axis through some interventional strategies (including diet, probiotics and postbiotics), may lead to a positive gene-environment interaction with improvement of immune-modulatory effects and final positive effect on human health. In particular probiotics and postbiotics exerting pleiotropic regulatory actions on the gut-microbiome-immune system axis provide an innovative preventive and therapeutic strategy for many pediatric conditions