Active deformation and relief evolution in the western Lurestan region of the Zagros mountain belt: new insights from tectonic geomorphology analysis and finite element modeling

none7noopenBasilici, M.; Ascione, A.; Megna, A.; Santini, S.; Tavani, S.; Valente, E.; Mazzoli, S.Basilici, M.; Ascione, A.; Megna, A.; Santini, S.; Tavani, S.; Valente, E.; Mazzoli, S

Moderate-intensity statin therapy seems ineffective in primary cardiovascular prevention in patients with type 2 diabetes complicated by nephropathy:a multicenter prospective 8 years follow up study

Background: Although numerous studies and metanalysis have shown the beneficial effect of statin therapy in CVD secondary prevention, there is still controversy such the use of statins for primary CVD prevention in patients with DM. The purpose of this study was to evaluate the occurrence of total major adverse cardio-vascular events (MACE) in a cohort of patients with type 2 diabetes complicated by nephropathy treated with statins, in order to verify real life effect of statin on CVD primary prevention. Methods: We conducted an observational prospective multicenter study on 564 patients with type 2 diabetic nephropathy free of cardiovascular disease attending 21 national outpatient diabetes clinics and followed them up for 8 years. 169 of them were treated with statins (group A) while 395 were not on statins (group B). Results: Notably, none of the patients was treated with a high-intensity statin therapy according to last ADA position statement. Total MACE occurred in 32 patients from group A and in 68 patients from group B. Fatal MACE occurred in 13 patients from group A and in 30 from group B; nonfatal MACE occurred in 19 patients from group A and in 38 patients from group B. The analysis of the Kaplan-Meier survival curves showed a not statistically significant difference in the incidence of total (p 0.758), fatal (p 0.474) and nonfatal (p 0.812) MACE between the two groups. HbA1c only showed a significant difference in the incidence of MACE between the two groups (HR 1.201, CI 1.041-1.387, p 0.012). Conclusions: These findings suggest that, in a real clinical setting, moderate-intensity statin treatment is ineffective in cardiovascular primary prevention for patients with diabetic nephropathy

Pre-buckling imperfection sensitivity of pultruded FRP profiles

This paper presents a geometrically non-linear one-dimensional model suitable for analyzing thin-walled fiber-reinforced polymer profiles, which accounts for the effect of manufacturing imperfections. The kinematic model is developed under the hypotheses of small strains and moderately large rotations of the cross-sections, and is able to take into consideration the contribution of shear strains and the effects related to warping displacements. The aim of the study is to develop a proper tool to analyze the pre-buckling behavior of such beams, since current approaches based on two-dimensional finite element method analysis demand significant computational efforts to be applied to real structures. The numerical results underline the effectiveness of the proposed mechanical model in analyzing case studies of technical interest in Civil Engineering, and the relevant influence of geometrical imperfections on the structural performance of FRP components with regard to serviceability design requirements

Local buckling behavior of FRP thin-walled beams:A mechanical model

A mechanical model able to predict the local buckling of pultruded FRP thin-walled beams and columns, taking into account the shear deformability of composite materials, is presented in this paper. The model is based on the individual analysis of the buckling of the components of the FRP profile, assumed as elastically restrained transversely isotropic plates. The analysis is developed within the hypotheses of small strains and moderate rotations

Buckling failure modes of FRP thin-walled beams

A study on buckling phenomena in pultruded Fiber Reinforced Polymers (FRP) beams, based on two mechanical models recently formulated by the authors with regard to composite thin-walled beams, is presented in this paper. Global buckling behavior is analyzed by means of a onedimensional model in which cross-section torsional rotation is divided into two parts: the first one, associated with Vlasov’s axial warping, the second one, associated entirely with shear strains. The study of local behavior is based on the individual buckling analysis of the components of FRP profile, assumed as elastically restrained transversely isotropic plates. Both mechanical models take into account, within the field of small strains and moderate rotations, the contribution of shear deformation in the kinematic hypotheses. Design charts suitable to evaluate the buckling load of FRP “I” beams with either narrow or wide flanges are obtained and presented in this paper

Macro-scale analysis of local and global buckling behavior of T and C composite sections

Buckling modes of pultruded Fiber Reinforced Polymer (FRP) beams are analyzed in this paper. The study is performed on the basis of two mechanical models recently proposed by the authors with regard to global and local buckling of composite thin-walled beams. These models are developed within the theory of small strains and moderate rotations and they take into account the contribution of shear deformation. The constitutive law here adopted is based on the homogenization of the material properties at the macro scale level. With regard to local stability, the junctions are considered as semi-rigid connections, whose stiffness is strongly influenced by the micro structure of the material. A discussion on the effects of the beam geometry and on the failure modes is presented. They may consist in local or global buckling as well as in material failure. Further, the global buckling may be torsional or lateral. The discussion is supported by non-dimensional diagrams which can be useful in design involving “T” and “C” sections subject to axial and bending loads