on the lateral stability of the sleeper ballast system

Abstract The lateral stability of railway tracks depends on all track components: rails, fastening systems, sleepers, ballast bed and substructure. Among them, the ballast is the weakest one and, due to its granular nature, experimental data obtained in line from full-scale tests, rather than based on analytical formulations, are used to describe its behavior. Until now, several studies have been carried out to quantify the effects of the track-bed geometrical parameters on the transverse strength of the track, but unfortunately not all the possible scenarios have been investigated. To fill this gap, a numerical-experimental research program of in-line tests has been developed in the framework of a cooperation between the Italian State Railways (RFI) and the Department of Industrial Engineering (DII) of the University of Naples Federico II. An ad hoc experimental testing plant, which is able to apply in a more realistic way the testing loads in field conditions, has been designed and realized. In the present paper, the test field is described, and both the features of the new testing plant and the advantages that this new system offers are detailed. Finally, from the analysis of the experimental data obtained from in-line tests carried out on some track panels representative of real scenarios, and with the help of atypical lateral resistance tests, an interesting property is utilized to predict a priori the lateral resistance curves of non tested scenarios

Short-term cardiac outcome in survivors of COVID-19: a systematic study after hospital discharge

Background COVID-19 has caused considerable morbidity and mortality worldwide and cardiac involvement has been reported during infection. The short-term cardiac outcome in survivors of COVID-19 is not known.Objective To examine the heart of patients who survived COVID-19 and to compare the cardiac outcome between patients who recovered from mild-to-moderate or severe illness.Methods With use of ECG and echocardiography, we examined the heart of 105 patients who had been hospitalized with COVID-19 and were consecutively recruited after hospital discharge while attending follow-up visits. Survivors of COVID-19 were compared with 105 matched controls. We also compared the cardiac outcome and lung ultrasound scan between COVID-19 patients who had mild-to-moderate or severe illness.Results Cardiac data were collected a median of 41 days from the first detection of COVID-19. Symptoms were present in a low percentage of patients. In comparison with matched controls, no considerable structural or functional differences were observed in the heart of survivors of COVID-19. Lung ultrasound scan detected significantly greater residual pulmonary involvement in COVID-19 patients who had recovered from severe than mild-to-moderate illness. No significant differences were detected in ECG tracings nor were found in the left and right ventricular function of patients who had recovered from mild-to-moderate or severe illness.Conclusions In a short-term follow-up, no abnormalities were identified in the heart of survivors of COVID-19, nor cardiac differences were detected between patients who had different severity of illness. With the limitations of a cross-sectional study, these findings suggest that patients who recover from COVID-19 do not have considerable cardiac sequelae.[GRAPHICS]

Management of intra-abdominal infections : recommendations by the WSES 2016 consensus conference

This paper reports on the consensus conference on the management of intra-abdominal infections (IAIs) which was held on July 23, 2016, in Dublin, Ireland, as a part of the annual World Society of Emergency Surgery (WSES) meeting. This document covers all aspects of the management of IAIs. The Grading of Recommendations Assessment, Development and Evaluation recommendation is used, and this document represents the executive summary of the consensus conference findings.Peer reviewe

Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity

The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)

A continuous model for the railway track analysis in the lateral plane

This paper deals with a mechanical model for the analysis of the railway track behaviour built by exploiting the periodicity of the track-structure. The starting point of this study is the analysis of the inner forces transferring modes. They have been determined by the unit principal vectors analysis of the base cell transfer matrix. The proposed model is able to reproduce accurately the track behaviour in transferring its inner forces. However, solutions that are equilibrated but not kinematically admissible are obtained from it when transversal loads are applied. In additions, only boundary conditions compatibles with the track transferring modes can be satisfied. This inconsistency is eliminated by superposition of a corrective deformed shape. This is derived from the eigenvectors of the transfer matrix pertaining to self-equilibrated systems of bending moments decaying along the track. The application field of the proposed track model is also discussed and the results of a validation study carried out by F.E. analysis are finally presented

Estimation of the wheel-rail lateral contact force through the analysis of the rail web bending strains

Vertical overloads and imbalances in the composition of a railway vehicle can result in damage to the track and in a non-conformity regarding safety of operation. On the other hand, wheel-rail lateral contact forces are more directly involved in the running safety and deserve a special focus. In this paper, an experimental approach to estimate lateral forces applied by rolling stock to the track is presented. The method is based on the analysis of bending strains in the cross plane of the rail web. This approach allows the decoupling of effects of the lateral force from those of the vertical one with a simple combination of bending stresses measured on the rail web. The research uses finite element simulations and laboratory tests. The numerical and experimental results have identified an independent coefficient from the applied loads by which it is possible estimate the magnitude of the lateral force

Valorization of by-products from Ribes nigrum bud-derivative food supplements: Pulsed Ultrasound-Assisted Extraction vs a second maceration

This study takes place in the context of an Alcotra Italy-France trans-frontier project called FINNOVER (2017-2020) whose main target is the implementation of new green chain productions exploiting the biodiversity of the ALCOTRA territory. One of the FINNOVER chain is devoted to the production of plant bud-derivatives, a specific category of botanicals. This relatively new category of natural products, marketed as plant food supplements in the most of European Community, is produced by macerating meristematic tissues of trees and plants (i.e. buds and young sprouts) mainly spontaneously collected. This maceration is traditionally made according to the European Pharmacopeia 8th edition procedure [1]. Due to the limited collection period of the raw vegetable material, bud-derivatives are very expensive products compared to other botanicals, therefore a potential valorization of their by-products could represent an important economical resource to be exploited. In this research, a re-use procedure to valorize Ribes nigrum bud by-products is presented. The wet marcs remaining after the production of the commercial glyceric macerate (GM) are extracted, using only a food-grade solvent (the same of the corresponding GM), both by a \u201csecond\u201d traditional maceration and by an innovative extraction technology. This latter one consists of a Pulsed Ultrasound-Assisted Extraction (PUAE) employed to extract further valuable material from bud by-products. Similarly to what already published for Castanea sativa bud by-products [2], the PUAE extraction has proven to be a very good recycle strategy: in this case a comparison with the \u201csecond\u201d traditional maceration has furtherly confirmed it. References [1] Ordre National des Pharmaciens (1965). Codex Fran\ue7ais, Monographie: Pr\ue9parations Hom\ue9opathiques. In V. I. I. I. Codex Medicamentarius Gallicus (Ed.). Pharmacop\ue9e Fran\ue7aise. Paris: Minist\ue8re de la sant\ue9 publique et de la population. [2] An innovative green extraction and re-use strategy to valorize food supplement by-products: Castanea sativa bud preparations as case study, Federica Turrini, Dario Donno, Raffaella Boggia, Gabriele Loris Beccaro, Paola Zunin, Riccardo Leardi, Anna Maria Pittaluga, Food Research International, 2019, Volume 115, Pages 276-282. doi.org/10.1016/j.foodres.2018.12.018

The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome

Idiopathic systemic capillary leak syndrome (ISCLS) is a rare disease that involves the endothelium and microcirculation, leading to an abrupt shift of fluids and proteins from the intravascular to the interstitial compartment. The consequence of the capillary leakage is a life-threatening hypovolemic shock that can lead to lethal multiple organ dysfunction. The autonomic nervous system (ANS) is central in regulating the cardiovascular response to hypovolemia, but ANS modulation in ISCLS has not yet been investigated. Here, we report ANS activity during acute phase and recovery from a severe ISCLS shock and speculate on the possibility that autonomic mechanisms underlie the pathogenesis of attacks

Prognostic Role of Malnutrition Diagnosed by Bioelectrical Impedance Vector Analysis in Older Adults Hospitalized with COVID-19 Pneumonia: A Prospective Study

Little is known on the clinical relevance of the nutritional status and body composition of patients hospitalized with SARS-CoV-2 infection. The aim of our study was to assess the prevalence of malnutrition in patients with COVID-19 pneumonia using bioelectrical impedance vector analysis (BIVA), and to evaluate the relationship of their nutritional status with the severity and outcome of disease