2,268 research outputs found
In and out from senescence
No full textCellular senescence has been widely recognised for decades as a stable arrest of cell proliferation. A recent study identifies senescence establishment and maintenance as a dynamic and reversible process regulated by (in)activation of a predetermined enhancer landscape controlled by the pioneer transcription factor AP-1
Intercellular Calcium Signaling Induced by ATP Potentiates Macrophage Phagocytosis
No full textSummary: Extracellular ATP is a signaling molecule exploited by the immune cells for both autocrine regulation and paracrine communication. By performing live calcium imaging experiments, we show that triggered mouse macrophages are able to propagate calcium signals to resting bystander cells by releasing ATP. ATP-based intercellular communication is mediated by P2X4 and P2X7 receptors and is a feature of pro-inflammatory macrophages. In terms of functional significance, ATP signaling is required for efficient phagocytosis of pathogen-derived molecules and apoptotic cells and may represent a target for macrophage regulation by CD39-expressing cells. These results highlight a cell-to-cell communication mechanism tuning innate immunity. : Exchange of information is critical for an efficient immune response. Here, Zumerle et al. show that macrophages exploit ATP release as a paracrine communication mechanism to propagate calcium signals to neighboring cells. Signal propagation relies on P2X4 and P2X7 receptors and sustains macrophage phagocytosis. Keywords: macrophage, adenosine triphosphate, calcium, phagocytosis, P2X receptor
EcoMug: An Efficient COsmic MUon Generator for cosmic-ray muon applications
No full textApplications of cosmic-ray (CR) muons have grown in numbers in the last decade. Measurements of flux attenuation (radiography) and scattering angles (tomography) of CR muons have been successfully applied to the inspection or monitoring of large natural and civil structures, to the search for heavy metals in container and trucks, to the control of nuclear wastes, and much more. In the present work, a new Monte Carlo generator of CR muons, called EcoMug and specifically designed for muon radiography and tomography applications, is presented. It is a header-only C++11 library, based on a parametrization of experimental data. Unlike other tools, EcoMug gives the possibility of generating from different surfaces (plane, cylinder and half-sphere), while keeping the correct angular and momentum distribution of generated tracks. For example, this flexibility allows for a very efficient generation of nearly horizontal muons, of great interest in many muon radiography and tomography applications, by using cylindrical or half-spherical generation surfaces. Finally, EcoMug also allows the generation of CR muons according to user-defined parametrizations of their differential flux. Main features of EcoMug, its mathematical foundation, as well as applications to selected study cases are presented
Reply to the Letter to the Editor “Androgen deprivation therapy may constitute a more effective prophylactic than therapeutic strategy in COVID-19 patients” by N. Bennani and I. M. Bennani-Baiti
No full textGenetic and hormonal influence on SARS-CoV-2-infection susceptibility: Re: The potential influence of human Y-chromosome haplogroup on COVID-19 prevalence and mortality
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A new Monte Carlo muon generator for cosmic-ray muon applications
No full textCosmic rays, thanks to their ubiquity and high penetration capability, have been successfully used in scientific research ever since their discovery. As soon as their knowledge improved, applications in the civil/environmental field were also developed: muon radiography (or muography, based on the flux attenuation) and muon tomography (based on the scattering angle) have been used to study the inner structure of volcanoes, to seek hidden rooms in Egyptian pyramids, to search for heavy metals in containers, and so on. And besides these imaging techniques, cosmic ray muons are also widely used for detector testing and alignment practically in every Nuclear Physics or Particle Physics experiment. Since most of these applications are sensitive to the angular and momentum distribution of cosmic muons, an accurate modelling of these distributions is a key feature for any generation tool conceived to simulate the cosmic muon flux. This can make the generator quite time-consuming, which is a strong limit when one needs to reach high statistics or to study large structures. A new Monte Carlo generator for cosmic-ray muons, named Efficient COsmic MUon Generator (EcoMug for short), especially designed to be fast (≳ 10^5 muons generated per second on a standard machine) without losing accuracy, is presented here. It is written as a header-only C++11 library, ready to be integrated into whatever C++ code, in particular C++ code based on Geant4 simulation tool. By default, EcoMug relies on a simple and effective parametrisation of the experimental data of cosmic ray differential flux at sea level, taken from the literature, but the library is written in such a way that every user can easily replace it with his own user-defined parametrisation. Unlike other tools, EcoMug is able to generate muons from different kind of surfaces (plane, cylinder and half-sphere), while keeping the correct angular and momentum distribution of generated tracks inside a fiducial volume. This allows to optimise the generation surface according to the system under study, and leads to a further improvement of the overall simulation efficiency. In this contribution we will present the main features of EcoMug, starting from its mathematical foundation, and eventually showing some interesting applications
Muography of different structures using muon scattering and absorption algorithms
No full textIn recent decades, muon imaging has found a plethora of applications in many fields. This technique succeeds to infer the density distribution of big inaccessible structures where conventional techniques cannot be used. The requirements of different applications demand specific implementations of image reconstruction algorithms for either multiple scattering or absorption-transmission data analysis, as well as noise-suppression filters and muon momentum estimators. This paper presents successful results of image reconstruction techniques applied to simulated data of some representative applications. In addition to well-known reconstruction methods, a novel approach, the so-called μCT, is proposed for the inspection of spent nuclear fuel canisters. Results obtained based on both μCT and the maximum-likelihood expectation maximization reconstruction algorithms are presented.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'
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