Analysis of the Invert Damage and Its Rehabilitation Design. The Saint Louis Les Aygalades Tunnel Case Study

The combined effect of time with the non-homogenous mechanical and hydraulic behaviors of the various intermediate layers between the foundation soil and the tracks often result in undesired deformation and misalignment of the tracks, which can compromise performance of the railway tunnel. The tunnel of Saint-Louis les Aygalades is located on the Paris Marseille mainline. This 476 m long tunnel was built in 1847, from the two portals and two intermediate shafts, under a maximum cover of 35 m in the tertiary formation of Stampien. The section of the tunnel consists of an elliptical vault with large vertical axis resting on the curved sidewalls and supported by a circular invert. The tunnel was entirely lined in masonry bricks with lime mortar. This paper presents an investigation into the behavior of the tracks in the Saint-Louis les Aygalades railway tunnel. The evolution of the tracks misalignment generated the undulatory deformation of the rails, which was caused by the non-homogeneity of the mechanical and hydraulic properties of the track structure. The modeling of the phases of construction and the time effect using the finite element analysis method made it possible to consider the structural role of the invert in the global stability of the tunnel liner. The study allowed the identification of possible causes of the track misalignment and determination of an appropriate solution. Corrective measures were assessed and applied

Rehabilitation of La Nerthe Tunnel on Paris-Marseille High-Speed Railway Line

The La Nerthe tunnel is located on the Paris-Marseille railway line under the Étoile mountain range. This 4638 m long double track tunnel was built at the middle of 19th century under a maximum cover of 180 m and currently is used as part of the high-speed railway line (TGV). This masonry tunnel with hard limestone blocks at the sidewalls and bricks at the crown passes through marl, gypsum and limestone zones. A major fault with accompanying extensive tectonic deformations cuts across the tunnel axis. The in-situ stress tests performed on the new high-speed rail line in the zone with intense tectonic fractures highlighted the tectonic residual stresses with very high lateral earth pressure coefficients (k0). The La Nerthe tunnel underwent ovalization deformation with excessive displacement at the springline, and pinching and bursting of the bricks at the crown. In this paper, the geological context and the damage to the tunnel lining are described in detail. The theoretical tunnel profile has been compared with the actual real section in order to determine the size and the shape of the lining deformation. The initialization of the existing stress field in the tunnel masonry lining using the original excavation and support methods and also a simplified approach for considering the time effect has been explained in detail. Finite element analyses have allowed an understanding of the possible causes of the observed damages and to propose an adequate reinforcement method. The applied rehabilitation system and the constraints of work in this busy mainline railway tunnel have been discussed in detail

Analysis of Tunnel Section Enlargement Through Cutting Masonry Liner (Paris-Marseilles Roches De Condrieu Railway Tunnel Case Study)

With increase in the dynamic envelope of trains due to the increase of their cross section and speed, the need for widening tunnel cross section of existing tunnels is becoming a necessity. One of the solutions to this problem consists of cutting a fraction of the masonry liner thickness and replacing it with a higher strength, and therefore, a thinner material. In this paper, the case of the widening of the Roches de Condrieu tunnel on the Paris to Marseilles railway line is presented. A maximum of half of the thickness of the existing masonry liner should be removed somewhere between the tunnel crown and the springline. Three-dimensional finite element analysis was used to simulate the effect of this partial cutting of the liner over a limited specified length along the tunnel axis. This study allowed the determination of the maximum length of cutting along the tunnel axis without creating any stability problem for the tunnel section. Once the section cut is reinforced by a higher strength material such as steel fiber reinforced shotcrete, the work resumed with alternating panels

Novel targets for antibacterial agents in Brucella sp.

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Novel targets for antibacterial agents in Brucella sp.

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Exclusion of Intra-Atrial Thrombus Diagnosis Using D-Dimer Assay Before Catheter Ablation of Atrial Fibrillation

International audienceObjectives: This study hypothesized that the association of D-dimer blood level and several clinical items in a new risk score could predict the absence of atrial thrombus.Background: Symptomatic and drug resistant atrial fibrillation (AF) can be treated by catheter ablation. The procedure-related risk of thromboembolism is limited by the pre-operative use of transesophageal echocardiography (TEE) to detect atrial thrombi.Methods: Patients admitted for catheter ablation of AF (n = 2,494) were prospectively included in a multicenter study. TEE was systematically performed before the procedure to search for atrial thrombus (primary endpoint). D-dimer level, CHADS2 score, left ventricular ejection fraction, pre-operative anticoagulation regimen, and medical history were collected. A logistic regression model was used to identify factors associated with the presence of atrial thrombus (hypertension, history of stroke, heart failure, D-dimer level >270 ng/ml). These factors were aggregated in a new score called atrial thrombus exclusion (ATE).Results: The incidence of atrial thrombus was 1.92%. CHADS2 score and D-dimer level were significantly associated with atrial thrombus (p < 0.0001 and p < 0.0001, respectively). A zero CHADS2 score failed to exclude all atrial thrombi (5 false negatives; sensitivity: 89.58%, specificity: 52.2%). No false negative was found with a zero ATE score, which had a specificity of 37% and a higher sensitivity (100%) than the CHADS2 score (p < 0.031) to predict the absence of intra-atrial thrombi on TEE. Conversely, the positive predictive value was poor, and the ATE score should not be used to conclude a positive diagnosis of thrombus.Conclusions: An ATE score of zero was strongly associated with the absence of atrial thrombus. This new score could be useful to rule out a diagnosis of atrial thrombus before catheter ablation of AF

Prognostic value of ventricular arrhythmia in early post-infarction left ventricular dysfunction: the French nationwide WICD-MI study

International audienceBackground and Aims Prophylactic implantable cardioverter–defibrillators (ICDs) are not recommended until left ventricular ejection fraction (LVEF) has been reassessed 40 to 90 days after an acute myocardial infarction. In the current therapeutic era, the prognosis of sustained ventricular arrhythmias (VAs) occurring during this early post-infarction phase (i.e. within 3 months of hospital discharge) has not yet been specifically evaluated in post-myocardial infarction patients with impaired LVEF. Such was the aim of this retrospective study. Methods Data analysis was based on a nationwide registry of 1032 consecutive patients with LVEF ≤ 35% after acute myocardial infarction who were implanted with an ICD after being prescribed a wearable cardioverter–defibrillator (WCD) for a period of 3 months upon discharge from hospital after the index infarction. Results ICDs were implanted either because a sustained VA occurred while on WCD (VA+/WCD, n = 72) or because LVEF remained ≤35% at the end of the early post-infarction phase (VA−/WCD, n = 960). The median follow-up was 30.9 months. Sustained VAs occurred within 1 year after ICD implantation in 22.2% and 3.5% of VA+/WCD and VA−/WCD patients, respectively (P &lt; .0001). The adjusted multivariable analysis showed that sustained VAs while on WCD independently predicted recurrence of sustained VAs at 1 year (adjusted hazard ratio [HR] 6.91; 95% confidence interval [CI] 3.73–12.81; P &lt; .0001) and at the end of follow-up (adjusted HR 3.86; 95% CI 2.37–6.30; P &lt; .0001) as well as 1-year mortality (adjusted HR 2.86; 95% CI 1.28–6.39; P = .012). Conclusions In patients with LVEF ≤ 35%, sustained VA during the early post-infarction phase is predictive of recurrent sustained VAs and 1-year mortality

Relation of outcomes to ABC (Atrial Fibrillation Better Care) pathway adherent care in European patients with atrial fibrillation: an analysis from the ESC-EHRA EORP Atrial Fibrillation General Long-Term (AFGen LT) Registry

International audienceAbstract Aims There has been an increasing focus on integrated, multidisciplinary, and holistic care in the treatment of atrial fibrillation (AF). The ‘Atrial Fibrillation Better Care’ (ABC) pathway has been proposed to streamline integrated care in AF. We evaluated the impact on outcomes of an ABC adherent management in a contemporary real-life European-wide AF cohort. Methods and results Patients enrolled in the ESC-EHRA EURObservational Research Programme in AF General Long-Term Registry with baseline data to evaluate ABC criteria and available follow-up data were considered for this analysis. Among the original 11 096 AF patients enrolled, 6646 (59.9%) were included in this analysis, of which 1996 (30.0%) managed as ABC adherent. Patients adherent to ABC care had lower CHA2DS2-VASc and HAS-BLED scores (mean ± SD, 2.68 ± 1.57 vs. 3.07 ± 1.90 and 1.26 ± 0.93 vs. 1.58 ± 1.12, respectively; P &lt; 0.001). At 1-year follow-up, patients managed adherent to ABC pathway compared to non-adherent ones had a lower rate of any thromboembolic event (TE)/acute coronary syndrome (ACS)/cardiovascular (CV) death (3.8% vs. 7.6%), CV death (1.9% vs. 4.8%), and all-cause death (3.0% vs. 6.4%) (all P &lt; 0.0001). On Cox multivariable regression analysis, ABC adherent care showed an association with a lower risk of any TE/ACS/CV death [hazard ratio (HR): 0.59, 95% confidence interval (CI): 0.44–0.79], CV death (HR: 0.52, 95% CI: 0.35–0.78), and all-cause death (HR: 0.57, 95% CI: 0.43–0.78). Conclusion In a large contemporary cohort of European AF patients, a clinical management adherent to ABC pathway for integrated care is associated with a significant lower risk for cardiovascular events, CV death, and all-cause death

The SAMe-TT2R2 score and quality of anticoagulation in atrial fibrillation: a simple aid to decision-making on who is suitable (or not) for vitamin K antagonists

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