New Frontiers on Seismic Modeling of Masonry Structures

An accurate evaluation of the non-linear behavior of masonry structural elements in existing buildings still represents a complex issue that rigorously requires non-linear finite element strategies difficult to apply to real large structures. Nevertheless, for the static and seismic assessment of existing structures, involving the contribution of masonry materials, engineers need reliable and efficient numerical tools, whose complexity and computational demand should be suitable for practical purposes. For these reasons, the formulation and the validation of simplified numerical strategies represent a very important issue in masonry computational research. In this paper, an innovative macroelement approach, developed by the authors in the last decade, is presented. The proposed macroelement formulation is based on different, plane and spatial, macroelements for the simulation of both the in-plane and out-of-plane behavior of masonry structures also in presence of masonry elements with curved geometry. The mechanical response of the adopted macroelement is governed by non-linear zero-thickness interfaces, whose calibration follows a straightforward fiber discretization, and the non-linear internal shear deformability is ruled by equivalence with a corresponding geometrically consistent homogenized medium. The approach can be considered as "parsimonious" since the kinematics of the adopted elements is controlled by very few degrees of freedom, if compared to a corresponding discretization performed by using non-linear finite element method strategies. This innovative discrete element strategy has been implemented in two user-oriented software codes 3DMacro (Caliò et al., 2012b) and HiStrA (Historical Structures Analysis) (Caliò et al., 2015), which simplify the modeling of buildings and historical structures by means of several wizard generation tools and input/output facilities. The proposed approach, that represents a powerful tool for the structural assessment of structures in which the masonry plays a key role, is here validated against experimental results involving typical masonry monumental substructural elements and numerical results involving real-scale structures

A procedure for the identification of multiple cracks on beams and frames by static measurements

In this work, a model of the Euler-Bernoulli beam in presence of multiple-concentrated open cracks, based on the adoption of a localized flexibility model, is adopted. The closed-form solution in terms of transversal displacements due to static loads and general boundary condition is exploited to propose an inverse damage identification procedure. The proposed identification procedure does not require any solution algorithm, on the contrary is formulated by means of simple explicit sequential expressions for the crack positions and intensities including the identification of the integration constants. The number of possible detected cracks depends on the couples of adopted sensors. Undamaged beam zones can also be easily detected in relation to the sensor positions. The analytical character of the explicit expressions of the identification procedure makes the inverse formulation applicable to damaged beams included in more complex frame structures. The proposed procedure is applied for the identification of the number, position, and intensity of the cracks along simple straight beams and also to more complex frame structures with the aim of showing its simplicity for engineering applications. In addition, the robustness of the methodology here described is shown through an accurate analysis of the basic assumptions on which the theory relies and by means of a study of the effect of noise on the identification results

Macitentan attenuates cardiovascular remodelling in infant rats with chronic lung disease

Background Cardiovascular impairment contributes to increased mortality in preterm infants with chronic lung disease. Macitentan, an endothelin-1 receptor antagonist, has the potential to attenuate pulmonary and cardiovascular remodelling. Methods In a prospective randomized placebo-controlled intervention trial, Sprague–Dawley rats were exposed to 0.21 or 1.0 fraction of inspired oxygen (FiO2) for 19 postnatal days. Rats were treated via gavage with placebo or macitentan from days of life 5 to 19. Alveoli, pulmonary vessels, α-smooth muscle actin content in pulmonary arterioles, size of cardiomyocytes, right to left ventricular wall diameter ratio, and endothelin-1 plasma concentrations were assessed. Results FiO2 1.0 induced typical features of chronic lung disease with significant alveolar enlargement (p = 0.012), alveolar (p = 0.048) and pulmonary vessel rarefaction (p = 0.024), higher α-smooth muscle actin content in pulmonary arterioles (p = 0.009), higher right to left ventricular wall diameter ratio (p = 0.02), and larger cardiomyocyte cross-sectional area (p  0.05). Conclusion The endothelin-1 receptor antagonist macitentan attenuated cardiovascular remodelling in an infant rat model for preterm chronic lung disease. This study underscores the potential of macitentan to reduce cardiovascular morbidity in preterm infants with chronic lung disease

Lung-borne systemic inflammation in mechanically ventilated infant rats due to high PEEP, oxygen, and hypocapnia

Background: Intensive care practice calls for ventilator adjustments due to fast-changing clinical conditions in ventilated critically ill children. These adaptations include positive end-expiratory pressure (PEEP), fraction of inspired oxygen (FiO2), and respiratory rate (RR). It is unclear which alterations in ventilator settings trigger a significant systemic inflammatory response. Methods: Fourteen-day old Wistar rat pups were randomized to the following groups: (a) “control” with tidal volume ~8 mL/kg, PEEP 5 cmH2O, FiO2 0.4, RR 90 min-1, (b) “PEEP 1”, (c) “PEEP 9” (d) “FiO2 0.21”, (e) “FiO2 1.0”, (f) “hypocapnia” with RR of 180 min-1, and (g) “hypercapnia” with RR of 60 min-1. Following 120 min of mechanical ventilation, plasma for inflammatory biomarker analyses was obtained by direct cardiac puncture at the end of the experiment. Results: Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were driven by FiO2 0.4 and 1.0 (P=0.02, P<0.01, respectively), tissue plasminogen activator inhibitor type-1 (tPAI-1) was increased by high PEEP (9 cmH2O, P<0.05) and hypocapnia (P<0.05), and TNF-α was significantly lower in hypercapnia (P<0.01). Tissue inhibitor of metalloproteinase-1 (TIMP-1), cytokine-induced neutrophil chemoattractant 1 (CINC-1), connective tissue growth factor (CTGF), and monocyte chemoattractant protein-1 (MCP-1) remained unaffected. Conclusion: Alterations of PEEP, FiO2, and respiratory frequency induced a significant systemic inflammatory response in plasma of infant rats. These findings underscore the importance of lung-protective ventilation strategies. However, future studies are needed to clarify whether ventilation induced systemic inflammation in animal models is pathophysiologically relevant to human infants

The Influence of the COVID‑19 Pandemic Emergency on Alcohol Use: A Focus on a Cohort of Sicilian Workers

The period between the beginning and the end of the COVID‑19 pandemic emergency generated a general state of stress, affecting both the mental state and physical well‑being of the gen‑ eral population. Stress is the body’s reaction to events or stimuli perceived as potentially harmful or distressing. Particularly when prolonged over time, it can promote the consumption of different psychotropic substances such as alcohol, and thus the genesis of various pathologies. Therefore, our research aimed to evaluate the differences in alcohol consumption in a cohort of 640 video work‑ ers who carried out activities in smart working, subjects particularly exposed to stressful situations due to the stringent rules of protection and prevention implemented during the pandemic. Further‑ more, based on the results obtained from the administration of the AUDIT‑C, we wanted to analyse the different modes of alcohol consumption (low, moderate, high, severe) to understand whether there is a difference in the amount of alcohol consumed that could predispose individuals to health problems. To this end, we administered the AUDIT‑C questionnaire in two periods (T0 and T1 ), co‑ inciding with annual occupational health specialist visits. The results of the present research showed an increase in the number of subjects consuming alcohol (p = 0.0005) and in their AUDIT‑C scores (p &lt; 0.0001) over the period considered. A significant decrease in subgroups who drink in a low‑risk (p = 0.0049) mode and an increase in those with high (p = 0.00012) and severe risk (p = 0.0002) were also detected. In addition, comparing the male and female populations, it emerged that males have drinking patterns that lead to a higher (p = 0.0067) health risk of experiencing alcohol‑related diseases than female drinking patterns. Although this study provides further evidence of the negative impact of the stress generated by the pandemic emergency on alcohol consumption, the influence of many other factors cannot be ruled out. Further research is needed to better understand the relationship between the pandemic and alcohol consumption, including the underlying factors and mechanisms driving changes in drinking behaviour, as well as potential interventions and support strategies to address alcohol‑related harm during and after the pandemic

A computational study of CO2 hydrogenation on single atoms of Pt, Pd, Ni and Rh on In2O3(111)

Metal promoted indium oxide (In2O3) catalysts are promising materials for CO2 hydrogenation to products such as methanol and carbon monoxide. The influence of the dispersion of the promoting metal on the methanol selectivity of In2O3 catalysts is a matter of debate, which centers around the role of atomically dispersed single metal atoms vs. metal clusters as catalysts for methanol formation. In this study, we used density functional theory calculations to compare the role of single atoms (SAs) of Ni, Pd, Pt and Rh placed on the In2O3(111) surface to study CO2 hydrogenation to CO and methanol. Direct and hydrogen-assisted CO2 dissociation pathways leading to CO as well as methanol formation via either formate or CO intermediates are explicitly considered. Microkinetic simulations show that all SA models mainly catalyze CO formation via a redox pathway involving oxygen vacancies where adsorbed CO2 dissociates followed by CO desorption and water formation. The higher barriers for hydrogenation of formate intermediates compared to the overall barrier for the rWGS reaction explain the negligible CH3OH selectivity.</p

Acetaldehyde effects in the brain

The effects of alcohol have been widely studied during the past century as alcohol abuse is a major health problem in Western society. In the last years, a growing body of evidence indicates that acetaldehyde, the first oxidation product of ethanol, is one of the mediators of peripheral and central effects of ethanol. Indeed, acetaldehyde has been recently taken into account as the mediator of the rewarding properties of alcohol. The role of acetaldehyde in ethanol-related properties has been proved by enzymatic manipulation studies in which the inactivation of acetaldehyde potentially synthesized in the brain produces the same results as blocking the formation of acetaldehyde by inhibiting brain catalase activity. Moreover, electrophysiological and pharmacological analyses showed that acetaldehyde is able to stimulate dopamine release in the nucleus accumbens through enhancement of firing rate, spikes/burst, and burst firing of ventral tegmental neurons. Thus, the aim of this review is to summarize latest results on the role of acetaldehyde as the mediator of ethanol-central effects

UPPER RESPIRATORY TRACT INFECTIONS IN CHILDREN: FROM CASE HISTORY TO MANAGEMENT

Respiratory tract infections are the most common diseases in childhood. The respiratory tract, widely branched system of ducts, is particularly exposed to the action of microorganisms transmitted by air from here the high frequency of infections they face especially in the first years of life. It is usual distinguish: upper respiratory tract infections (URTI) and lower respiratory tract infections (LRTI). In particular, in infections of the upper airways, the inflammatory process, result of the interaction between microbes and the immune response, can be localized to the mucosa of the nose or sinuses (common cold and sinusitis), or the pharynx or larynx (pharyngotonsillitis and laryngitis) and it has predominantly a viral etiology although occasionally it may be followed by bacterial complications such as otitis media. The aim of the following article is the description of these different clinical pictures, highlighting the clinical and epidemiological features and current management guidelines