Energy absorbing 4D printed meta-sandwich structures: load cycles and shape recovery

The present study investigates the behavior of solid cellular structures in polylactic acid (PLA) achieved by FDM technology (fusion deposition modelling). The geometries are permanently deformed by compressive stress and then subjected to shape recovery through the application of a thermal stimulus. The structures are submitted to medium-high and medium-low compression stresses, evaluating the mechanical properties and the absorption energy as the number of cycles varies. The study shows that the ability to absorb energy is related to the density of the model, as well as the degree of damage observed, which increases with increasing number of load cycles. The strongest geometry is the lozenge grid, which is the most reliable. It shows no damage with increasing compression cycles and keeps its capability to absorb energy almost constant. The increase in lozenge grid density leads to an improvement in both mechanical strength and absorption energy, as well as a lower incidence of microcracks in the geometry itself due to the repeated load cycles. These results open up a broad spectrum of applications of custom-designed solid cellular structures in the field of energy absorption and damping

Life Cycle Assessment (LCA) of ceramic sanitaryware: focus on the production process and analysis of scenario

The reduction of environmental impact is today the main challenge of the ceramic industry that is always more focusing on materials in line with the principles of economic and environmental sustainability. In this context, this study addresses the implementation of a Life Cycle Assessment (LCA) on the production of ceramic sanitaryware, based on a cradle-to-grave analysis. Specifically, the process was considered from raw materials until the product is manufactured, excluding the disposal phase except for process waste. The analysis of the impact assessment considers three different scenarios: (i) The first examines the current state; (ii) the second considers the recovery of fired waste and water as well as the replacement of firing and annealing ovens with new generation ovens; (iii) the third, in addition to the technologies used in the second, proposes the use of a photovoltaic system to produce green energy and, additionally, a "plant" energy recovery system. The results show how production processes have a considerable impact on the environment, in terms of energy consumption and materials. Moreover, the use of a photovoltaic system together with the recovery of water allows a significant reduction of environmental impacts. In contrast, the crushing processes for the recovery of fired waste worsen the environmental performance of the plant, because of the high consumption of electricity. Therefore, by improving the waste recovery system and adopting the solutions of the third scenario in terms of energy savings, it would be possible to reduce the environmental burden of the production system considerably. At the same time, the use of additional equipment and production processes increases the costs of the manufacturing and has a significant impact on maintenance

Life cycle assessment (LCA) of PET and PLA bottles for the packaging of fresh pasteurised milk. The role of the manufacturing process and the disposal scenario

Environmental protection issues are at the forefront of the vast majority of the media and public opinion. The study in question revealed the life cycle of a product commonly used in the home, the bottle of fresh pasteurised milk. The materials used for the manufacturing of the bottles are PET (PolyEthylene Terephthalate), plastic derived from fossil resources, and PLA (PolyLactic Acid), bioplastic derived from sugar cane, therefore from renewable resources. The life cycle of the bottles was carried out by highlighting the extraction phase of raw materials, the production of polymer, bottle, other packaging and distribution of milk and lastly, final disposal, excluding the phase of use, not significant for the purposes of this study. The studies were focused on two disposal scenarios, the current scenario and the one that is likely to take place in 10 years. In the current disposal scenario, there is no clear reduction in environmental impact from the comparison of the materials examined. With reference to the 2030 disposal scenario, the PLA turns out to be much more environmentally friendly

On the Mechanism of Levosimendan-Induced Dopamine Release in the Striatum of Freely Moving Rats

The Ca2+ sensitizer levosimendan (LEV) improves myocardial contractility by enhancing the sensitivity of the contractile apparatus to Ca2+. In addition, LEV promotes Ca2+ entry through L-type channels in human cardiac myocytes. In this study, which was performed using microdialysis, infusion of LEV at 0.25 μM for 160 min increased dopamine (DA) concentrations (up to fivefold baseline) in dialysates from the striatum of freely moving rats. Ca2+ omission from the perfusion fluid abolished baseline DA release and greatly decreased LEV-induced DA release. Reintroduction of Ca2+ in the perfusion fluid restored LEV-induced DA release. Chelation of intracellular Ca2+ by co-infusing 1,2-bis (o-amino-phenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra (acetoxymethyl) ester (BAPTA-AM, 0.2 mM) did not affect basal DA release and scarcely affected LEV-induced increases in dialysate DA. In addition, co-infusion of the L-type (Cav 1.1 – 1.3) voltage-sensitive Ca2+-channel inhibitor nifedipine failed to inhibit LEV-induced increases in dialysate DA, which, in contrast, was inhibited by co-infusion of the N-type (Cav 2.2) voltage-sensitive Ca2+-channel inhibitor ω-conotoxin GVIA. We conclude that LEV promotes striatal extracellular Ca2+ entry through N-type Ca2+ channels with a consequent increase in DA release. Keywords:: levosimendan, microdialysis, striatal dopamine, calcium entr

Modelling West Nile Virus and Usutu Virus Pathogenicity in Human Neural Stem Cells

West Nile virus (WNV) and Usutu virus (USUV) are genetically related neurotropic mosquito-borne flaviviruses, which frequently co-circulate in nature. Despite USUV seeming to be less pathogenic for humans than WNV, the clinical manifestations induced by these two viruses often overlap and may evolve to produce severe neurological complications. The aim of this study was to investigate the effects of WNV and USUV infection on human induced pluripotent stem cell-derived neural stem cells (hNSCs), as a model of the neural progenitor cells in the developing fetal brain and in adult brain. Zika virus (ZIKV), a flavivirus with known tropism for NSCs, was used as the positive control. Infection of hNSCs and viral production, effects on cell viability, apoptosis, and innate antiviral responses were compared among viruses. WNV displayed the highest replication efficiency and cytopathic effects in hNSCs, followed by USUV and then ZIKV. In these cells, both WNV and USUV induced the overexpression of innate antiviral response genes at significantly higher levels than ZIKV. Expression of interferon type I, interleukin-1\u3b2 and caspase-3 was significantly more elevated in WNV- than USUV-infected hNSCs, in agreement with the higher neuropathogenicity of WNV and the ability to inhibit the interferon response pathway

Modelling neurotropic flavivirus infection in human induced pluripotent stem cell-derived systems

Generation of human induced pluripotent stem cells (hiPSCs) and their differentiation into a variety of cells and organoids have allowed setting up versatile, non-invasive, ethically sustainable, and patient-specific models for the investigation of the mechanisms of human diseases, including viral infections and host-pathogen interactions. In this study, we investigated and compared the infectivity and replication kinetics in hiPSCs, hiPSC-derived neural stem cells (NSCs) and undifferentiated neurons, and the effect of viral infection on host innate antiviral responses of representative flaviviruses associated with diverse neurological diseases, i.e., Zika virus (ZIKV), West Nile virus (WNV), and dengue virus (DENV). In addition, we exploited hiPSCs to model ZIKV infection in the embryo and during neurogenesis. The results of this study confirmed the tropism of ZIKV for NSCs, but showed that WNV replicated in these cells with much higher efficiency than ZIKV and DENV, inducing massive cell death. Although with lower efficiency, all flaviviruses could also infect pluripotent stem cells and neurons, inducing similar patterns of antiviral innate immune response gene expression. While showing the usefulness of hiPSC-based infection models, these findings suggest that additional virus-specific mechanisms, beyond neural tropism, are responsible for the peculiarities of disease phenotype in humans