Local amplification of deep mining induced vibrations - Part.2: Simulation of the ground motion in a coal basin

This work investigates the impact of deep coal mining induced vibrations on surface constructions using numerical tools. An experimental study of the geological site amplification and of its influence on mining induced vibrations has already been published in a previous paper (Part 1: Experimental evidence for site effects in a coal basin). Measurements have shown the existence of an amplification area in the southern part of the basin where drilling data have shown the presence of particularly fractured and soft stratigraphic units. The present study, using the Boundary Element Method (BEM) in the frequency domain, first investigates canonical geological structures in order to get general results for various sites. The amplification level at the surface is given as a function of the shape of the basin and of the velocity contrast with the bedrock. Next, the particular coal basin previously studied experimentally (Driad-Lebeau et al., 2009) is modeled numerically by BEM. The amplification phenomena characterized numerically for the induced vibrations are found to be compatible with the experimental findings: amplification level, frequency range, location. Finally, the whole work was necessary to fully assess the propagation and amplification of mine induced vibrations. The numerical results quantifying amplification can also be used to study other coal basins or various types of alluvial sites

Sensory Map Transfer to the Neocrotex Relies on Pretarget Ordering of Thalamic Axons

Sensory maps, such as the representation of mouse facial whiskers, are conveyed throughout the nervous system by topographic axonal projections that preserve neighboring relationships between adjacent neurons. In particular, the map transfer to the neocortex is ensured by thalamocortical axons (TCAs), whose terminals are topographically organized in response to intrinsic cortical signals. However, TCAs already show a topographic order early in development, as they navigate toward their target. Here, we show that this preordering of TCAs is required for the transfer of the whisker map to the neocortex. Using Ebf1 conditional inactivation that specifically perturbs the development of an intermediate target, the basal ganglia, we scrambled TCA topography en route to the neocortex without affecting the thalamus or neocortex. Notably, embryonic somatosensory TCAs were shifted toward the visual cortex and showed a substantial intermixing along their trajectory. Somatosensory TCAs rewired postnatally to reach the somatosensory cortex but failed to form a topographic anatomical or functional map. Our study reveals that sensory map transfer relies not only on positional information in the projecting and target structures but also on preordering of axons along their trajectory, thereby opening novel perspectives on brain wiring

Vie r\ue9elle apr\ue8s l\u2019implantation d\u2019une neuromodulation sacr\ue9e : taux, raisons et facteurs de risque d\u2019interruption du suivi \ue0 mi-parcours

Abstract: Objectives. - To evaluate follow-up after implantation of a sacral nerve modulation implantable pulse generator (IPG) and to investigate the reasons and risk factors for follow-up discontinuation. Materials and methods. - All patients who underwent an IPG implantation to treat lower urinary tract symptoms between 2014-2019 within 6 hospital centers located in the district of "Hauts-de-France" (France) were systematically called during the year 2020 for a standardized (tele)consultation. Patients were divided into 3 distinct profiles according to the regularity of their 5-year postoperative follow-up: "Regular follow-up", "Irregular follow-up" and "Lost to follow-up". The primary outcome was the change in the annual proportion of the 3 follow-up profiles over the 5 years following IPG implantation. As secondary outcomes we described the reasons reported for follow-up discontinuation and looked for risk factors associated with. Results. - Overall, 259 patients were included. At the time of data collection, after a mean follow-up of 28.4 (+/- 19.8) months, 139 patients (53.7%) had a "Regular follow-up", 54 (20.8%) had an "Irregular follow-up" and 66 (25.5%) were "Lost to follow-up". The proportion of patients with a "Regular follow-up" decreased year by year, representing only 46.2% of patients at five-years. 175 patients (67.6%) underwent a standardized (tele)consultation. In multivariate analysis, only "lack of knowledge of the follow-up protocol" was statistically associated with follow-up discontinuation (OR = 5.16; 95% CI [2.12-13.57]). Conclusion. - The proportion of patients followed up after IPG implantation decreased steadily over the years, often related to a lack of therapeutic education. Level of evidence.- 4. (c) 2023 Elsevier Masson SAS. All rights reserved

Emergent growth cone responses to combinations of Slit1 and Netrin 1 in thalamocortical axon topography

How guidance cues are integrated during the formation of complex axonal tracts remains largely unknown. Thalamocortical axons (TCAs), which convey sensory and motor information to the neocortex, have a rostrocaudal topographic organization initially established within the ventral telencephalon [1, 2, 3]. Here, we show that this topography is set in a small hub, the corridor, which contains matching rostrocaudal gradients of Slit1 and Netrin 1. Using in vitro and in vivo experiments, we show that Slit1 is a rostral repellent that positions intermediate axons. For rostral axons, although Slit1 is also repulsive and Netrin 1 has no chemotactic activity, the two factors combined generate attraction. These results show that Slit1 has a dual context-dependent role in TCA pathfinding and furthermore reveal that a combination of cues produces an emergent activity that neither of them has alone. Our study thus provides a novel framework to explain how a limited set of guidance cues can generate a vast diversity of axonal responses necessary for proper wiring of the nervous system