68 research outputs found
Bond behavior of geopolymer concrete with steel and GFRP bars
No full textIn the last years geopolymer concrete (GPC) has shown great potential for use in structural elements. In this context, it has become fundamental to investigate on the bond behavior of this new concrete matrix with reinforcing bars. Data found in literature showed that GPC performs better than ordinary Portland cement (OPC) concrete in terms of bonding with deformed steel bars. In addition, few authors have focused in the study of the bond stress-slip behavior between GPC and glass fiber-reinforced polymer (GFRP) rebars. In this paper the bond -slip behavior of GPC with both steel and GFRP reinforcing bars will be investigated by means of pull-out test with centered bar setup also considering the effect of the bond length. The main results showed that little difference in bond-slip behavior occur between the two different steel bar diameters used. On the other hand, sand-coated GFRP bars showed lower bond capacity in respect to deformed steel bars. Finally, an increase in ultimate bond load has been observed when the bond length was increased
Comparative effect of microsomal enzymes inducers and inhibitors on urine mutagenicity of rats treated with either diesel particulate or organic extracts
No full textRare germline variants in DNA repair-related genes are accountable for papillary thyroid cancer susceptibility
No full textBackground: Understanding the molecular mechanisms underlying papillary thyroid cancer (PTC) proved to be vital not only for diagnostic purposes but also for tailored treatments. Despite the strong evidence of heritability, only a small subset of alterations has been implicated in PTC pathogenesis. To this reason, we used targeted next-generation sequencing (NGS) to identify candidate variants implicated in PTC pathogenesis, progression, and invasiveness. Methods: A total of 42 primary PTC tissues were investigated using a targeted next-generation sequencing (NGS) panel enlisting 47 genes involved in DNA repair and tumor progression. Results: We identified 57 point mutations in 78.5% of samples (n = 32). Thirty-two somatic mutations were identified exclusively in known thyroid cancer genes (BRAF, KRAS, NRAS, and TERT). Unpredictably, 45% of the all identified mutations (n = 25) resulted to be germline, most affecting DNA repair genes. Interestingly, none of the latter variants was in the main population databases. Following ACMG classification, 20% of pathogenic/likely pathogenic and 68% of variant of unknown significance were identified. Conclusions: Overall, our results support the hypothesis that rare germline variants in DNA repair genes are accountable for PTC susceptibility. More data, including the segregation analysis in affected families, should be collected before definitely annotate these alterations and to establish their potential prognostic and treatment implications
Damage assessment of an existing RC infilled structure by numerical simulation of the dynamic response
No full textThis paper proposes a dynamic structural health monitoring and damage detection method to assess the structural integrity and safety of an RC framed building with masonry infills. The effectiveness of the method is verified by numerical analyses that were performed on a RC moment-resisting frame structure investigated by Paultre et al. and applied on an existing RC framed building with masonry infill walls, which provide a strong contribution to the dynamic response and seismic performance of the building. Different damage states are simulated through the nonlinear static (pushover) analysis developed by the FE model of the building, and this analysis considers both the bare framed structure and the infilled structure to appraise the damage to the infill walls. The identification and location of the damage is estimated using the modal properties of the damaged building at various steps of the nonlinear analysis. The results highlight the different evolutions of the damage in the bare and infilled frames and the possibility of detection via dynamic monitoring
Bond behavior of geopolymer concrete with steel and GFRP bars
No full textIn the last years geopolymer concrete (GPC) has shown great potential for use in structural elements. In this context, it has become fundamental to investigate on the bond behavior of this new concrete matrix with reinforcing bars. Data found in literature showed that GPC performs better than ordinary Portland cement (OPC) concrete in terms of bonding with deformed steel bars. In addition, few authors have focused in the study of the bond stress-slip behavior between GPC and glass fiber-reinforced polymer (GFRP) rebars. In this paper the bond-slip behavior of GPC with both steel and GFRP reinforcing bars will be investigated by means of pull-out test with centered bar setup also considering the effect of the bond length. The main results showed that little difference in bond-slip behavior occur between the two different steel bar diameters used. On the other hand, sand-coated GFRP bars showed lower bond capacity in respect to deformed steel bars. Finally, an increase in ultimate bond load has been observed when the bond length was increased
Assessment of the in-plane deformability of RC floors with traditional and innovative lightening elements in RC framed and wall structures
No full textIn this paper, the in-plane deformability of floors in Reinforced Concrete (RC) structures has been investigated in order to establish the role of lightening elements made of both traditional ceiling bricks and Expanded Polystyrene (EPS) blocks. The study has been firstly developed via the implementation of three-dimensional finite element models simulating the real geometry of the floors. The numerical results have been, then, used to assess the thickness of equivalent slabs introduced in three-dimensional finite elements models of simple structures made of Reinforced Concrete frames or walls. These models have been used for verifying the effective in-plane floor deformability as a function of the vertical resistant elements typology (frames or walls), the building geometry (plane shape ratio, height, number of floor, dimensions of vertical elements), and the thickness of the equivalent slab. The numerical analyses have enabled to give interesting indications about the reliability of the hypothesis of rigid floors as the investigated parameters change
Geopolymer Concrete Structures: Bond with Deformed Steel Bars
No full textThe promising performances showed by geopolymer concrete led several researchers to investigate about possibilities of using this material in reinforced structural elements. Since geopolymer binder has a different microstructure from Ordinary Portland Cement (OPC) it is necessary to investigate, also, on its bonding behavior with steel bar that as well-known influences the service and ultimate conditions. For this reason, in the last decades both direct pull-out and beam-end tests were carried out with this material. Generally, it has been observed that Geopolymer Concrete (GPC) has higher bond strength than OPC concrete due to the higher compression strength and the dense and compact microstructure of GPC. This means that the existing design equation for bond strength prediction of ordinary concrete can be conservatively used also for GPC. In this paper the bond-slip behavior between GPC and steel reinforcing bar with two different diameters has been investigated
Randomized-comparison study on dissection of the central compartment of the neck and no surgical dissection in patients with initial thyroid cancer, negative pre-operative neck lymph-node diagnosis and intermediate–high molecular risk
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