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Cigarette smoke is associated to severe chronic diseases. The most harmful components of cigarette smoke derive from the combustion process, which are significantly reduced in the electronic cigarette aerosol, thus providing a valid option in harm reduction strategies. To develop safer products, it is therefore necessary to screen electronic cigarette liquids (e‐liquids) to meet high safety standards defined by government regulations. The aim of the present study was to evaluate the presence of metal‐ and plastic‐derived contaminants in four different commercial e‐liquids with high concentration of nicotine and their cytotoxic effect in normal human bronchial epithelial cells by a number of in vitro assays, in comparison with the 1R6F reference cigarette, using an air‐liquid interface (ALI) exposure system. Moreover, we evaluated the effect of aerosol exposure on oxidative stress by measuring the production of reactive oxygen species and mitochondrial potential. Our results showed no contaminants in all e‐liquids and a significantly reduced cytotoxic effect of e‐liquid aerosol compared to cigarette smoke as well as a maintained mitochondria integrity. Moreover, no production of reactive oxygen species was detected with e‐cigarette aerosol. In conclusion, these results support the reduced toxicity potential of e‐cigs compared to tobacco cigarettes in an in vitro model resembling real life smoke exposure. [ABSTRACT FROM AUTHOR]

The safety of museum exhibitions has recently become a challenging issue due to the newly different conception of the Museum as a creative and interactive place, where people can be also close to the artefacts. The way of exhibit art objects needs accurate study to assure the simultaneous safety of both artefacts and visitors according to the current increasing safety standards. The earthquakes are the main cause of damage and even failure of art objects, especially in small museums and churches that are largely diffused all over Europe. Therefore, the low-cost protection of artefacts and visitors is key in earthquake-prone areas. In several cases art objects can be modelled as rigid bodies placed on a moving base. To capture their mechanical response, the Housner theory, developed at the beginning of the sixties, represents a valid and accurate tool. Based on this theory, this paper presents a new approach for the preservation of museum artefacts through a low-cost isolation strategy. Art objects are considered as rigid bodies placed on a shaking base and their response is modelled considering both rocking and sliding motions. This paper highlights the need for a correct optimisation of both base shape and friction coefficient in order to drive the artefact response in more stable dynamics regions. The proposed approach effectiveness is tested on a real case study, an acephalous marble statue in the Archaeological Museum of Paestum. [ABSTRACT FROM AUTHOR]

A method is presented for evaluating the axial critical loads and deformed shapes of a Vierendeel periodic girder. They are obtained by solving the large-deflections equilibrium problem of a micro-polar equivalent model. The elastic properties of this model have been derived from those of an ideal girder whose cells may deform only according to the inner forces transferring modes of the unit cell. In particular, the strain energy density of the equivalent medium is obtained by evaluating the limit of the girder elastic energy for the cell to girder size ratio tending to zero. To solve the Engesser/Haringx discord, the large-deflections equilibrium equations are deduced by the virtual work principle, without any a priori assumption on the shear force. For this aim, also the external work of the substitute medium is evaluated by the same procedure as the strain energy density. Actually, it is first written for the ideal girder under the assumption of negligibility of the axial effects at the cell scale and then specialized for the continuous medium by examining the limit value for cell to girder size ratio going to zero. Closed form solutions for the critical deformed shapes are given, together with an accurate formula for the girder buckling load. [ABSTRACT FROM AUTHOR]

Unreinforced masonry is the most diffused construction material in the major part of historical centers in Europe. In a building subjected to earthquake forces the contribution of in-plane shear resistance of the masonry walls is a determinant factor for the stability of the whole structure. In particular, the masonry piers are the structural elements subjected to the combination of normal and shear forces. In general, ductile tools to model the in plane behaviour of masonry are always welcome in order to evaluate the capacity of walls subjected to vertical and horizontal actions. In this framework, two no-tension approaches to model the behaviour of masonry walls loaded with in-plane forces, involving a minimum energy procedure, are presented. Both the procedures allow the representation of the stress maps in the panel in case of monotonic increase of shear load. The results of the numerical analyses are compared and discussed. [ABSTRACT FROM AUTHOR]