Developing a laboratory facility to assess friction coefficients of standing samples

The numerical representation of the dynamic response of art works is the most reliable instrument to predict their seismic safety. Their adoption, however, require the knowledge of the effective mechanical properties of the artifacts and their restraint conditions. Namely, the amount of friction arising between standing art works and their supports largely affects the quality of their collapse and, therefore, the choice of the model to adopt in the analysis. In this work a facility for assessing the dynamic contact behaviour of marble sample standing on different supports has been investigated. The facility consists of a dynamic test to perform through the bidirectional shaking table at the Disaster Resilience Simulation Laboratory at the Politecnico di Torino. The friction coefficient has been found from the dynamic test by comparing the acceleration registered at the load cell, which is related to the reaction of the sample, and one measured at the shaking table surface. The obtained values of friction coefficient have been related to the velocity of the adopted input. A preliminary test on a single concrete sample has been performed to check the proposed procedure, by considering three different loading conditions: one of them is the acceleration history of a real ground motion, while the other two have a constant amplitude and a constant frequency, respectively

Damage risk assessment of historical asset using laser scan and finite element approach

Most part of valuable art goods are conserved in the Museums, which are in charge of their maintenance and their exposure; some of them, however, have an outdoor location, enriching the artistic and touristic worth of the towns which host them. The art works have an intrinsic vulnerability, due to their irregular shape, slenderness, fragility and - as concerns some sculptures of historical centers - to their oldness. The outdoor artifacts, however, have further hazard sources, since they can hardly be guarded, and they are subjected to possible vandalism actions and lunatic or terrorist attacks. In this work the dynamic response of artifacts to blasts of assigned intensity are investigated on a case-study, i.e. the Fountain of Neptune, located in "Piazza della Signoria", in Florence. The Fountain of Neptune is a marble and bronze opus made by Bartolomeo Ammannati between 1560 and 1565. The main character of the Fountain, Neptune, is a marble statue 5.7 meters tall, with a weight equal to 11.5 ton. A preliminary laser scanner survey has been made to achieve the geometrical representation of the statue. The considered load condition consists of an explosion caused by 10 kg of TNT placed at 8 meters from the Fountain. The dynamic behavior of the complex under the assumed load has been represented through a numerical analysis, by considering the main statue only - since it is the slenderest element of the complex - and by assuming it as simply supported on the pedestal, without any connector. The obtained results showed the vulnerability of the statue to the assumed blast, and pointed out the role plaid by the contact assumption on its dynamic response

Analysis of vibrations recorded inside the cemetery area of Incisa, central Italy

Seismic stations are usually used to record seismic event and, therefore, they are recommended to be installed far from railways and traffic roads in order to avoid the superposition of ambient noise signals to those provoked by an earthquake. In this paper, instead, seismic stations, placed intentionally in areas near railway and traffic roads, are used to characterize the subsoil spectral properties and to assess the effect of vibrations due to trains and vehicles. A cemetery in the green countryside near Florence is chosen as a reference case study to deal with this topic. Most of the buildings in the cemetery area are affected by an extensive crack pattern. In January 2020 five seismic stations were installed in order to evaluate if the trains running in the tunnels of the regional and high-speed railway lines located below and in the vicinity of the cemetery and the vehicles traveling on the nearby A1 highway and regional road can produce vibrations in the ground that justify the observed damage pattern.Collected data are analyzed using the Nakamura technique in order to estimate the dynamic properties of the ground and compared to the limits provided by the current regulations. Furthermore, the trend of the Root Mean Square average over the entire recording period is computed as well.From the obtained results, it is possible to highlight that the average daily oscillation level increases from early morning until 7 p.m. and then it decreases, and also that the highest amplitudes of transients are concentrated in the late evening and during the night, when the background noise is lower.Furthermore, the computed values of the maximum and average amplitudes are lower than those that can cause damage to buildings as defined by the guidelines, the eigenfrequency of the ground falls in a range far from that ascribable to the cemetery buildings, so that the resonance effects can be excluded. In order to confirm these results, the amplitude of ground shaking due to recorded transients is compared to that produced by two earthquakes (a 3.4 Mw local earthquake at more than 100 km and a Mw 6.6 teleseism from Turkey) which occurred during the monitoring period. One can conclude that it seems unlikely that the shaking produced by nearby vehicles and trains could be responsible for the observed damage

Anti-oxidant potential and gap junction-mediated intercellular communication as early biological markers of mercuric chloride toxicity in MDCK cell line.

In this study, the early nephrotoxic potential of mercuric chloride (HgCl(2)) has been evaluated in vitro, by exposing a renal-derived cell system, the tubular epithelial Madin-Darby canine kidney (MDCK) cell line, to the presence of increasing HgCl(2) concentrations (0.1-100 microM) for different periods of time (from 4 to 72 h). As possible biological markers of the tubular-specific toxicity of HgCl(2) in exposed-MDCK cultures we analysed: (i) critical biochemical parameters related to oxidative stress conditions and (ii) gap-junctional function (GJIC). HgCl(2) cytotoxicity was evaluated by cell-density assay. The biochemical analysis of the pro-oxidant properties of the mercuric ion (Hg(2+)) was performed by evaluating the effect of the metal salt on the antioxidant status of the MDCK cells. The cell glutathione (GSH) content and the activity of glutathione peroxidase (Gpx) and catalase (Cat), two enzymes engaged in the H(2)O(2) degradation, were quantified. HgCl(2) influence on MDCK GJIC was analysed by the microinjection/dye-transfer assay. HgCl(2)-induced morphological changes in MDCK cells were also taken into account. Our results, proving that subcytotoxic (0.1-10 microM) HgCl(2) concentrations affect either the antioxidant defences of MDCK cells or their GJIC, indicate these critical functions as suitable biological targets of early mercury-induced tubular cell injury

Cannabinoid receptor agonist WIN 55,212-2 inhibits rat cortical dialysate gamma-aminobutyric acid levels

The effects of the cannabinoid receptor agonist WIN 55,212-2 (0.1-5 mg/kg i.p.) on endogenous extracellular gamma-aminobutyric acid (GABA) levels in the cerebral cortex of the awake rat was investigated by using microdialysis. WIN 55,212-2 (1 and 5 mg/kg i.p.) was associated with a concentration-dependent decrease in dialysate GABA levels (-16% +/- 4% and -26% +/- 4% of basal values, respectively). The WIN 55,212-2 (5 mg/kg i.p.) induced-inhibition was counteracted by a dose (0.1 mg/kg i.p.) of the CB(1) receptor antagonist SR141716A, which by itself was without effect on cortical GABA levels. These findings suggest that cannabinoids decrease cortical GABA levels in vivo, an action that might underlie some of the cognitive and behavioral effects of acute exposure to marijuana

Effect of the administration of n-3 polyunsaturated fatty acids on circulating levels of microparticles in patients with a previous myocardial infarction

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Different Factors Affecting Human ANP Amyloid Aggregation and Their Implications in Congestive Heart Failure

Atrial Natriuretic Peptide (ANP)-containing amyloid is frequently found in the elderly heart. No data exist regarding ANP aggregation process and its link to pathologies. Our aims were: i) to experimentally prove the presumptive association of Congestive Heart Failure (CHF) and Isolated Atrial Amyloidosis (IAA); ii) to characterize ANP aggregation, thereby elucidating IAA implication in the CHF pathogenesis.A significant prevalence (85\%) of IAA was immunohistochemically proven ex vivo in biopsies from CHF patients. We investigated in vitro (using Congo Red, Thioflavin T, SDS-PAGE, transmission electron microscopy, infrared spectroscopy) ANP fibrillogenesis, starting from α-ANP as well as the ability of dimeric β-ANP to promote amyloid formation. Different conditions were adopted, including those reproducing β-ANP prevalence in CHF. Our results defined the uncommon rapidity of α-ANP self-assembly at acidic pH supporting the hypothesis that such aggregates constitute the onset of a fibrillization process subsequently proceeding at physiological pH. Interestingly, CHF-like conditions induced the production of the most stable and time-resistant ANP fibrils suggesting that CHF affected people may be prone to develop IAA.We established a link between IAA and CHF by ex vivo examination and assessed that β-ANP is, in vitro, the seed of ANP fibrils. Our results indicate that β-ANP plays a crucial role in ANP amyloid deposition under physiopathological CHF conditions. Overall, our findings indicate that early IAA-related ANP deposition may occur in CHF and suggest that these latter patients should be monitored for the development of cardiac amyloidosis

Quality of life and treatment satisfaction in adults with Type 1 diabetes: A comparison between continuous subcutaneous insulin infusion and multiple daily injections

Aims: The aim of this case-control study was to compare quality of life (QoL) and treatment satisfaction in adults with Type 1 diabetes (T1DM) treated with either continuous subcutaneous insulin infusion (CSII) or multiple daily injections (MDI). Methods: Consecutive patients aged between 18 and 55 years, and attending diabetes clinics for a routine visit, completed the Diabetes-Specific Quality-of-Life Scale (DSQOLS), the Diabetes Treatment Satisfaction Questionnaire (DTSQ) and the SF-36 Health Survey (SF-36). Case (CSII) and control subjects (MDI) were recruited in a 1 : 2 ratio. Results: Overall, 1341 individuals were enrolled by 62 diabetes clinics; 481 were cases and 860 control subjects. Cases had a longer diabetes duration and were more likely to have eye and renal complications. Age, school education, occupation and HbA1c were similar. Of control subjects, 90% followed glargine-based MDI regimens and 10% used NPH-based MDI regimens. On multivariate analysis, after adjusting for socioeconomic and clinical characteristics, scores in the following areas of the DSQOLS were higher in cases than control subjects: diet restrictions (β = 5.96; P < 0.0001), daily hassles (β = 3.57; P = 0.01) and fears about hypoglycaemia (β = 3.88; P = 0.006). Treatment with CSII was also associated with a markedly higher DTSQ score (β = 4.13; P < 0.0001) compared with MDI. Results were similar when CSII was compared separately with glargine- or NPH-based MDI regimens. Conclusions: This large, non-randomized, case-control study suggests quality of life gains deriving from greater lifestyle flexibility, less fear of hypoglycaemia, and higher treatment satisfaction, when CSII is compared with either glargine-based or NPH-based MDI regimens. © 2008 The Authors