Theoretical procedure to predict the local buckling resistance of aluminium members in elastic-plastic range

In the present research work, a theoretical approach to evaluate the ultimate resistance of aluminium alloy members subjected to local buckling under uniform compression is provided

A narrative review on the implementation of liquid biopsy as a diagnostic tool in thoracic tumors during the COVID-19 pandemic

Objective: In this review, we evaluate the role of liquid biopsy in managing lung cancer patients during the still ongoing coronavirus disease 2019 (COVID-19) healthcare emergency. Background: The novel influenza coronavirus (severe acute respiratory syndrome coronavirus or SARSCoV-2) has upended several aspects of our lives, including medical activities. In this setting, many routine cancer diagnostic and therapeutic procedures have been suspended, leading to delays in diagnosis, treatments, and, ultimately, increases in cancer mortality rates. Equally drastic has been the impact of COVID-19 on clinical trials, many of which have been stalled or have never begun. This has left many patients who were hoping to receive innovative treatments in a limbo. Although, as of today, the introduction of drastic security measures has been crucially important to contain the pandemic, one cannot ignore the need to continue providing chronically ill patients all the health care they need, in terms of detection, prevention, and treatment. In these unprecedented times, liquid biopsy, more than ever before, may play a relevant role in the adequate management of these frail patients. Methods: we performed a deep analysis of the recent international literature published in English on PUBMED in the last six months focused on the impact of SARS-CoV-2 on the management of lung cancer patients, focusing the attention on the role of liquid biopsy. Conclusions: COVID-19 pandemic has significantly modified our lives and overall medical practice. In these unprecedented times, liquid biopsy may represent a valid and less time-consuming diagnostic approach than conventional tissue and cytological specimens

MEDIATE - Molecular DockIng at homE: Turning collaborative simulations into therapeutic solutions

IntroductionCollaborative computing has attracted great interest in the possibility of joining the efforts of researchers worldwide. Its relevance has further increased during the pandemic crisis since it allows for the strengthening of scientific collaborations while avoiding physical interactions. Thus, the E4C consortium presents the MEDIATE initiative which invited researchers to contribute via their virtual screening simulations that will be combined with AI-based consensus approaches to provide robust and method-independent predictions. The best compounds will be tested, and the biological results will be shared with the scientific community.Areas coveredIn this paper, the MEDIATE initiative is described. This shares compounds' libraries and protein structures prepared to perform standardized virtual screenings. Preliminary analyses are also reported which provide encouraging results emphasizing the MEDIATE initiative's capacity to identify active compounds.Expert opinionStructure-based virtual screening is well-suited for collaborative projects provided that the participating researchers work on the same input file. Until now, such a strategy was rarely pursued and most initiatives in the field were organized as challenges. The MEDIATE platform is focused on SARS-CoV-2 targets but can be seen as a prototype which can be utilized to perform collaborative virtual screening campaigns in any therapeutic field by sharing the appropriate input files

Numerical Application of Effective Thickness Approach to Box Aluminium Sections

The ultimate behaviour of aluminium members subjected to uniform compression or bending is strongly influenced by local buckling effects which occur in the portions of the section during compression. In the current codes, the effective thickness method (ETM) is applied to evaluate the ultimate resistance of slender cross-sections affected by elastic local buckling. In this paper, a recent extension of ETM is presented to consider the local buckling effects in the elastic-plastic range and the interaction between the plate elements constituting the cross-section. The theoretical results obtained with this approach, applied to box-shaped aluminium members during compression or in bending, are compared with the experimental tests provided in the scientific literature. It is observed that the ETM is a valid and accurate tool for predicting the maximum resistance of box-shaped aluminium members during compression or in bending

Probabilistic Theory of Plastic Mechanism Control for Steel Moment Resisting Frames

This work aims at the development of an advanced method for the seismic design of Moment Resisting Frames (MRFs) based on a target value of the failure probability in the attainment of a collapse mechanism of global type for stochastic frames (considering the aleatoric uncertainty of the material properties). Therefore, the method herein presented constitutes the probabilistic version of the Theory of Plastic Mechanism Control (TPMC) already developed for frames with deterministic material properties. With reference to MRFs whose members have random values of the yield strength, when structural collapse is of concern, the failure domain is related to all the possible collapse mechanisms. Within the probabilistic TPMC, the term “failure” does not mean the attainment of a structural collapse, but the development of a collapse mechanism different from the global one. The design requirements normally needed to prevent undesired collapse mechanisms are probabilistic events within the framework of the kinematic theorem of plastic collapse. The limit state function corresponding to each event is represented by a hyperplane in the space of random variables, so that the failure domain is a surface resulting from the intersection of the hyperplanes corresponding to the limit states representing the single failure events. Since plastic hinges in frame's members are common to many different mechanisms, the single limit state events are correlated. Therefore, by applying the theory of binary systems and considering that the limit states are events located in series, the probability of failure can be computed by means of Ditlevsen bounds. This approach has been validated by means of Monte Carlo simulations. In order to achieve a predefined level of reliability in the attainment of the design goal, the reliability analysis is repeated for increasing values of the overstrength factor of the dissipative zones to be used in TPMC, aiming to its calibration. Finally, on the basis of the results of a parametric analysis, a simple relationship to compute the value of the overstrength factor needed to include the influence of random material variability in the application of TPMC is proposed

STOCHASTIC APPROACH FOR THEORY OF PLASTIC MECHANISM CONTROL

The present work aims at the development of an advanced method for the seismic design of Moment Resisting Frames (MRFs) based on the valuation of the probability of failure in the development of a collapse mechanism of global type in case of stochastic frames. Therefore, this method represents the probabilistic version of the Theory of Plastic Mechanism Control (TPMC) [1] already successfully developed for frames with deterministic material properties. With reference to MRFs whose members have random values of the yield strength, the failure domain derives from all the possible collapse mechanisms. Under the point of view of structural reliability analysis [2], the term "failure" means the attainment of a collapse mechanism different from the global one. The design requirements normally needed to prevent undesired collapse mechanisms are probabilistic events within the framework of the kinematic theorem of plastic collapse. At each event corresponds a limit state function representing a hyperplane in the space of the random variables, so that the failure domain is a manifold surface resulting from the intersection of the hyperplanes corresponding to the limit states of the single events. Because of plastic hinges in frame's members are common to many different mechanisms, the single limit state events are correlated. Therefore, by applying the theory of binary systems [2] and taking into account that, from a structural reliability point of view, the limit states are events located in series, the probability of failure is computed by means of Ditlevsen bounds

Ultimate resistance and rotation capacity of low yielding high hardening aluminium alloy beams under non-uniform bending

The aim of this work is the study of the ultimate response of aluminium alloy beams subjected to non-uniform bending. The analysis of H and I-sections made of temper T4 and temper T5 is presented. A comprehensive parametric analysis has been carried out by a FEM model developed with ABAQUS computer program. The parameters investigated are the flange slenderness, the flange-to-web slenderness ratio and the non-dimensional shear length accounting for the moment gradient. They represent the main geometrical parameters governing the ultimate resistance and the rotation capacity of H-shaped or I-shaped aluminium beams. The results of the numerical simulations are used to calibrate empirical formulations for predicting the ultimate bending resistance and the rotation capacity of low yielding high hardening aluminium beams made of H or I-sections, depending on their geometrical and mechanical properties

Validation of probabilistic theory of plastic mechanism control by means of Monte Carlo simulations

This work aims at the validation of the Probabilistic Theory of Plastic Mechanism Control (P-TPMC), reported in a companion paper, by means of Monte Carlo simulations. P-TPMC is devoted to stochastic frames with the aim to assure a collapse mechanism of global type despite of the influence of random material variability. A mechanism of global type develops when all the beams are yielded at their ends while the columns remain in elastic range with the only exception of the base sections of the first storey columns. A parametric analysis is performed considering steel moment resisting frames having different number of bays and different number of storeys. Moreover, in order to achieve a predefined level of reliability in the attainment of the design goal, the parametric analysis is also repeated for increasing values of an overstrength factor of the dissipative zones aiming to its calibration. Finally, a quadratic regression has been derived to provide a simple relationship to compute the value of the overstrength factor needed to include the influence of random material variability in the application of deterministic Theory of Plastic Mechanism Control