47 research outputs found
Suitable design approaches for interfaces involving geosynthetics under various loading and flow conditions.
No full textThis work integrates the research results conducted over several
years, focusing on the behaviour of interfaces in applications involving
geosynthetics. It addresses the importance of accurately characterizing the
interfaces of geosynthetic-reinforced soil walls and steep slopes, landfill
cover systems, and drainage systems to ensure their performance under both
ultimate and serviceability limit states. For geosynthetic-reinforced soil
walls and steep slopes, the research emphasizes the proper characterization
of soil-geosynthetic interfaces under static and cyclic loading conditions,
both in the short- and long-term. It provides essential guidelines for selecting
design parameters for these structures, ensuring their stability under various
loading scenarios. In landfill cover systems, the study investigates the
behaviour of interfaces between different geosynthetics under static and
seismic loading conditions, with special attention to potential damage
arising from improper installation. The lecture offers a comprehensive
approach to understanding these interactions and their impact on the longterm
performance of landfill systems. Lastly, the research examines the
soil/geotextile filter interfaces in drainage systems, particularly in contact
with unstable cohesionless soils under different boundary conditions. It
challenges conventional design methods and introduces a new methodology
to design filter transitions in contact with internally unstable soils. These
findings significantly contribute to designing and optimising geosynthetic
applications in civil engineering, advancing theoretical understanding and
practical implementation
Cytotoxicity, oxidative stress and genotoxicity induced by glass fibers on human alveolar epithelial cell line A549
No full textMan-made vitreous fibers have been widely used as insulation material as asbestos substitutes; however their morphology and composition raises concerns. In 1988 the International Agency for Research on Cancer classified fiberglass, rock wool, slag wool, and ceramic fibers as Group 2B, i.e. possibly carcinogenic to humans. In 2002 it reassigned fiberglass, rock and slag wool, and continuous glass filaments to Group 3, not classifiable as carcinogenic to humans. The aim of this study was to verify the cytotoxic and genotoxic effects and oxidative stress production induced by in vitro exposure of human alveolar epithelial cells A549 to glass fibers with a predominant diameter 5μm (93%). A549 cells were incubated with 5, 50, or 100μg/ml (2.1, 21, and 42μg/cm(2), respectively) of glass fibers for 72h. Cytotoxicity and DNA damage were tested by the MTT and the Comet assay, respectively. Oxidative stress was determined by measuring inducible nitric oxide synthase (iNOS) expression by Western blotting, production of nitric oxide (NO) with Griess reagent, and concentration of reactive oxygen species by fluorescent quantitative analysis with 2',7'-dichlorofluorescein-diacetate (DCFH-DA). The results showed that glass fiber exposure significantly reduced cell viability and increased DNA damage and oxidative stress production in a concentration-dependent manner, demonstrating that glass fibers exert cytotoxic and genotoxic effects related to increased oxidative stress on the human alveolar cell line A549
Essential amino acids improve insulin activation of Akt/mTOR signaling in soleus muscle of aged rats
No full textEssential amino acids (EAA) improve basal muscle protein synthesis in the elderly. Nevertheless, in settings of prolonged supplementation, putative signal pathways of EAA are currently unknown. The purpose of this study was to test the effects of prolonged supplementation of EAA enriched mixture (12-L-Amin) on Insulin/Insulin-like Growth Factor-1 (IGF1) pathway by measuring total and phosphorylated Akt (Ser473) and its upstream (IRS1 at Ser636) and downstream (mTOR at Ser2448, p70S6K at Thr389) targets in basal conditions and following acute insulin (0.1 U/L) incubation in vitro. To this aim, soleus muscles were dissected from male Wistar rats divided in three groups of 7 each: adults (AD, 10 mo of age), elderly (EL, 22 mo of age) and elderly supplemented (EL-AA, 12-L-Amin 1.5gr/Kg die in drinking water for 3 mo). EL showed reduced basal and post-insulin mTOR and p70S6K activation and reduced post-insulin IRS1 degradation relative to AD. EL-AA showed an increase of post-insulin Akt activation, no change in basal and post-insulin phospho-mTOR, lower reduction of phospho-p70S6K and increased post-insulin IRS1 degradation relative to AD. These results demonstrate that chronic 12-LAmin administration exerts anti-ageing effects on the activation/inactivation of the Insulin/IGF1/mTOR pathway which is identified as putative target of EAA in the elderly
In-air Tensile Load-strain Behaviour of HDPE Geogrids Under Cyclic Loading
No full textAbstractThe knowledge of geosynthetics mechanical behaviour under static and cyclic loads is important in order to develop constitutive models to be used in numerical analyses of geosynthetic reinforced structures.The paper describes a series of wide-width monotonic and multistage tensile tests on HDPE extruded uniaxial geogrids with different tensile stiffness. The cyclic tensile tests have been performed using a multistage procedure varying the pre-stress tensile load, the cyclic tensile loading amplitude and the frequency. The influence of these parameters on the residual strains (defined as the strain value when cyclic loads returns to the pre-stress load) has been analysed
Twelve Novel Mutations in the SLC26A3 Gene in 17 Sporadic Cases of Congenital Chloride Diarrhea
No full textObjectives: We aimed to improve the knowledge of pathogenic mutations in
sporadic cases of congenital chloride diarrhea (CCD) and emphasize the
importance of functional studies to define the effect of novel mutations.
Methods: All member 3 of solute carrier family 26 (SLC26A3) coding
regions were sequenced in 17 sporadic patients with CCD. Moreover, the
minigene system was used to analyze the effect of 2 novel splicing
mutations.
Results: We defined the SLC26A3 genotype of all 17 patients with CDD
and identified 12 novel mutations. Using the minigene system, we confirmed
the in silico prediction of a complete disruption of splicing pattern caused
by 2 of these novel mutations: the c.971þ3_971þ4delAA and
c.735þ4_c.735þ7delAGTA. Moreover, several prediction tools and a
structure-function prediction defined the pathogenic role of 6 novel
missense mutations.
Conclusions: We confirm the molecular heterogeneity of sporadic CDD
adding 12 novel mutations to the list of known pathogenic mutations.
Moreover, we underline the importance, for laboratories that offer
molecular diagnosis and genetic counseling, to perform fast functional
analysis of novel mutation
Probabilistic Analyses of Root-Reinforced Slopes Using Monte Carlo Simulation
No full textAmong measures that are used to prevent the triggering of shallow landslides and for erosion control, root reinforcement has spread out widely as its contribution to environmental sustainability is high. Although in recent years reliability-based design (RBD) has been applied increasingly to the assessment of slope stability to address the shortcomings of the deterministic approach (which does not consider geotechnical uncertainties explicitly), there is still a lack in the application of this method to root reinforcement. Plants are characterised by high inherent uncertainty, making it necessary to investigate the level of reliability of these soil-bioengineering techniques. In this context, to determine whether or not root-reinforced slopes designed according to Eurocodes (that is, by applying their statistical partial factors), and providing satisfactory factors of safety, may lead to a probability of failure that is, in contrast, unacceptable, the Authors carried out several probabilistic analyses by using Monte Carlo simulation (MCS). MCS was applied to the simplified Bishop Method modified to bear pseudo-static forces representing earthquake loading in mind. To take into account the mechanical effect provided by roots, an apparent root cohesion was added to the Mohr–Coulomb failure criterion. Results showed that not every slope configuration that satisfies the safety criterion has acceptable levels of reliability, and this evidence is caused by the high variability of the design parameters
Analisi CFD degli attraversamenti sull'intercooler di una vettura ad alte prestazioni
No full textNel presente lavoro viene analizzata l'influenza dei principali parametri CFD di una simulazione numerica effettuata con codice commerciale (la Griglia di calcolo, i modelli di turbolenza più usati e la comprimibilità) sulla portata di massa di una vettura ad elevate prestazioni. La vettura in esame presenta il radiatore nella parte posteriore della stessa dove il flusso è caratterizzato da separazioni e non stazionarietà
Deformative behaviour of different geogrids embedded in a granular soil under monotonic and cyclic pullout loads
No full text
Branched-Chain Amino Acid Supplementation Promotes Survival and Supports Cardiac and Skeletal Muscle Mitochondrial Biogenesis in Middle-Aged Mice
No full textSummaryRecent evidence points to a strong relationship between increased mitochondrial biogenesis and increased survival in eukaryotes. Branched-chain amino acids (BCAAs) have been shown to extend chronological life span in yeast. However, the role of these amino acids in mitochondrial biogenesis and longevity in mammals is unknown. Here, we show that a BCAA-enriched mixture (BCAAem) increased the average life span of mice. BCAAem supplementation increased mitochondrial biogenesis and sirtuin 1 expression in primary cardiac and skeletal myocytes and in cardiac and skeletal muscle, but not in adipose tissue and liver of middle-aged mice, and this was accompanied by enhanced physical endurance. Moreover, the reactive oxygen species (ROS) defense system genes were upregulated, and ROS production was reduced by BCAAem supplementation. All of the BCAAem-mediated effects were strongly attenuated in endothelial nitric oxide synthase null mutant mice. These data reveal an important antiaging role of BCAAs mediated by mitochondrial biogenesis in mammals
