Publications associées à Spin cascade and doming in ferric hemes: Femtosecond X-ray absorption and X-ray emission studies

Direct observations of X-rays produced by upward positive lightning

Farhad Rachidi-Haeri, Marcos Rubinstein, Antonio Sunjerga, Thomas Chaumont

X-rays have been observed in natural downward cloud-to-ground lightning for over 20 years and in rocket-triggered lightning for slightly less. In both cases, this energetic radiation has been detected during the stepped and dart leader phases of downward n ...

Nature Publishing Group2024

A new step forward in realistic cluster lens mass modelling: analysis of Hubble Frontier Field Cluster Abell S1063 from joint lensing, X-ray, and galaxy kinematics data

Johan Richard, Jean-Paul Richard Kneib, Mathilde Jauzac, Benjamin Yvan Alexandre Clement, Benjamin Emmanuel Nicolas Beauchesne

We present a new method to simultaneously and self-consistently model the mass distribution of galaxy clusters that combines constraints from strong lensing features, X-ray emission, and galaxy kinematics measurements. We are able to successfully decompose ...

Oxford Univ Press2023

Topology Repairing of Disconnected Pulmonary Airways and Vessels: Baselines and a Dataset

Jiancheng Yang

Accurate segmentation of pulmonary airways and vessels is crucial for the diagnosis and treatment of pulmonary diseases. However, current deep learning approaches suffer from disconnectivity issues that hinder their clinical usefulness. To address this cha ...

Springer International Publishing Ag2023

Ultrafast X-ray Spectroscopy of Haem Proteins

Majed Chergui, Camila Bacellar Cases Da Silveira

In this article we revisit our recent picosecond and femtosecond X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) experiments, probing the ultrafast electronic and geometric evolution of photoexcited haem proteins, namely ferrous N ...

SWISS CHEMICAL SOC2022

Disparate temperature-dependent virus-host dynamics for SARS-CoV-2 and SARS-CoV in the human respiratory epithelium

Bastien Mangeat, Bart Deplancke, Julie Marie Russeil, Daniel Alpern, Vincent Roland Julien Gardeux, Elisa Cora, Jörn Pezoldt

Since its emergence in December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally and become a major public health burden. Despite its close phylogenetic relationship to SARS-CoV, SARS-CoV-2 exhibits increased human-to- ...

2021

Insights into the microbial reduction of pentavalent and hexavalent uranium species by Shewanella oneidensis MR-1

Margaux Camille Andréa Molinas

Decades of uranium-related activities such as ore mining, nuclear power generation, weapon manufacture, storage of nuclear wastes, have contributed to the release of U in the environment. U occurrence is concerning, since in surface environments, U is typi ...

EPFL2021

Ultrafast X-ray Spectroscopy of Heme Proteins

Dominik Kinschel

With the advent of X-ray free-electron lasers (XFELs) time-resolved X-ray spectroscopic techniques have advanced to the femtosecond regime. These are element selective techniques which offer unique insight into the electronic and chemical environment and d ...

EPFL2020

High intensity x-ray interaction with a model bio-molecule system: double-core-hole states and fragmentation of formamide

Christoph Bostedt, Yiming Li

Formamide, a simple model bio-molecule (HCONH2), is irradiated with high intensity, ultrashort pulses from an x-ray free electron laser. Ionic fragments resulting from photoionization and subsequent decay processes are recorded, as well as the electronic s ...

IOP Publishing2020

Micrometer-resolution X-ray tomographic full-volume reconstruction of an intact post-mortem juvenile rat lung

Anders Larsson, Marco Stampanoni, Goran Lovric

In this article, we present an X-ray tomographic imaging method that is well suited for pulmonary disease studies in animal models to resolve the full pathway from gas intake to gas exchange. Current state-of-the-art synchrotron-based tomographic phase-con ...

SPRINGER2021

Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy

Andre Al Haddad, Christoph Bostedt, Jonas Knurr, Siqi Li, Zhaoheng Guo

The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray t ...

ROYAL SOC CHEMISTRY2020

Mechanism(s) of electron transfer and metabolic changes during iron reduction by Clostridium acetobutylicum

Cornelia List

Microorganisms catalyze many of the redox transformations driving the iron cycle in the geosphere. For instance, iron cycling includes the reduction of solid-phase and soluble ferric iron (Fe(III)) to ferrous iron (Fe(II)). However, in order to reduce soli ...

EPFL2019

Charge-carrier Dynamics in Metal Oxides and Hybrid Lead Perovskites investigated by Time-Resolved UV and X-ray Spectroscopy

Thomas Charles Henry Rossi

In modern ultrafast optoelectronic technologies based on wide band gap insulators, the non-equilibrium dynamics of photogenerated charges plays a major role. Unravelling the mechanisms of interaction between these charge carriers and their environment is c ...

EPFL2018

The small RNA RyhB is a regulator of cytochrome expression in Shewanella oneidensis

Rizlan Bernier-Latmani, Karin Lederballe Meibom

Shewanella oneidensis produces an extensive electron transfer network that results in metabolic flexibility. A large number of c-type cytochromes are expressed by S. oneidensis and these function as the fundamental electron transport chain proteins. Althou ...

Frontiers Media SA2018

Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

Thomas Günther Bretz

Aims. We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fer ...

Edp Sciences S A2017

Multiwavelength observations of a VHE gamma-ray flare from PKS 1510-089 in 2015

Thomas Günther Bretz

Context. PKS 1510 089 is one of only a few flat spectrum radio quasars detected in the very-high-energy (VHE, > 100 GeV) gamma-ray band. Aims. We study the broadband spectral and temporal properties of the PKS 1510 089 emission during a high gamma-ray stat ...

Edp Sciences S A2017

Fixed Energy X-ray Absorption Voltammetry and Extended X-ray Absorption fine Structure of Ag nanoparticle electrodes

Christos Comninellis

FEXRAV (Fixed Energy X-ray Absorption Voltammetry) has been recently introduced as a powerful tool in electrochemistry. It consists in measuring the X-ray absorption coefficient at a fixed X-ray energy while the electrochemical potential of the material un ...

Elsevier Science Sa2016

Searches for the Anomalous Photon Polarisation in Radiative B Decays at LHCb

Zhirui Xu

This thesis is exploring the measurements of the photon polarisation in radiative

B

decays at LHCb, which are mediated through

b\to s\gamma

transitions. To ensure optimal physics performance, procedures to align the LHCb detector and to monitor the ali ...

EPFL2016

The electronic, chemical and electrocatalytic processes and intermediates on iron oxide surfaces during photoelectrochemical water splitting

Michael Graetzel, Yelin Hu, Artur Braun, Florent Alexandre Boudoire

We re-assess experimental soft X-ray absorption spectra of the oxygen K-shell which we recorded operando from iron oxide during photoelectrochemical water splitting in KOH electrolyte. In particular, we refer to recently reported transitional electron hole ...

Elsevier2016

Photo-induced dynamics of the heme centers in cytochrome bc(1)

Majed Chergui, Frank van Mourik, Andre Al Haddad, Adrien Alexis Paul Chauvet

The ultrafast response of cytochrome bc1 is investigated for the first time, via transient absorption spectroscopy. The distinct redox potentials of both c(1)- and b-hemes allow for a clear differentiation of their respective signals. We find that while th ...

Royal Society of Chemistry2015

Multiwavelength observations of Mrk 501 in 2008

Thomas Günther Bretz, Xin Chen

Context. Blazars are variable sources on various timescales over a broad energy range spanning from radio to very high energy (>100 GeV, hereafter VHE). Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its firs ...

Edp Sciences S A2015