Publications associées à Quantitative phase-contrast tomography of a liquid phantom using a conventional x-ray tube source

In vivo X-ray microtomography locally affects stem radial growth with no immediate physiological impact

Pascal Turberg, Laura Mekarni, Charlotte Grossiord, Hervé Cochard

Microcomputed tomography (mu CT) is a nondestructive X-ray imaging method used in plant physiology to visualize in situ plant tissues that enables assessments of embolized xylem vessels. Whereas evidence for X-ray-induced cellular damage has been reported, ...

Oxford Univ Press Inc2024

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

X-ray chemical imaging for assessing redox microsites within soils and sediments

Vincent Noel, Meret Aeppli

Redox reactions underlie several biogeochemical processes and are typically spatiotemporally heterogeneous in soils and sediments. However, redox heterogeneity has yet to be incorporated into mainstream conceptualizations and modeling of soil biogeochemist ...

Frontiers Media Sa2024

Impact of CO2-rich seawater injection on the flow properties of basalts

Lyesse Laloui, Eleni Stavropoulou, Cesare Griner

Permanent CO storage in basalts through mineralisation offers a promising solution for reducing carbon emissions and mitigating climate change. This study focuses on the impact of potential mineralisation on the flow properties of the basaltic material. Fl ...

2024

Effect of wettability and textile architecture on fluid displacement and pore formation during infiltration of carbon fibrous preforms

Véronique Michaud, Baris Çaglar, Helena Luisa Teixido Pedarros

We seek to address how air entrapment mechanisms during infiltration are influenced by the wetting characteristics of the fluid and the pore network formed by the reinforcement. To this end, we evaluated the behavior of two model fluids with different surf ...

Elsevier Sci Ltd2023

Modulation of the nanoscale motion rate of Candida albicans by X-rays

Sandor Kasas, María Inés Villalba

IntroductionPatients undergoing cancer treatment by radiation therapy commonly develop Candida albicans infections (candidiasis). Such infections are generally treated by antifungals that unfortunately also induce numerous secondary effects in the patient. ...

Frontiers Media SA2023

Measurement and modelling of dynamic fluid saturation in carbon reinforcements

Véronique Michaud, Baris Çaglar, Helena Luisa Teixido Pedarros, Guillaume Clément Broggi

We propose a methodology to monitor the progressive saturation of a non-translucent unidirectional carbon fabric stack through its thickness by means of X-ray radiography and extract the dynamic saturation curves using image analysis. Four constant flow ra ...

2023

Hydrogenated amorphous silicon high flux x-ray detectors for synchrotron microbeam radiation therapy

Sylvain Dunand, Nicolas Würsch, Giulia Rossi, Matthew James Large

Objective. Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity ...

IOP Publishing Ltd2023

CEERS Key Paper. VI. JWST/MIRI Uncovers a Large Population of Obscured AGN at High Redshifts

Michaela Hirschmann

Mid-infrared (mid-IR) observations are powerful in identifying heavily obscured active galactic nuclei (AGN) that have weak emission in other wavelengths. Data from the Mid-Infrared Instrument (MIRI) on board the James Webb Space Telescope provides an exce ...

2023

Optical and mid-infrared line emission in nearby Seyfert galaxies

Michaela Hirschmann

Line ratio diagnostics provide valuable clues as to the source of ionizing radiation in galaxies with intense black hole accretion and starbursting events, such as local Seyfert galaxies or galaxies at the peak of their star formation history. We aim to pr ...

2023

Cross verified independent measurements of correlated bubble property distributions as part of the scale-up of a catalytic bubbling fluidized bed reactor

Philipp Fedor Riechmann

Methanation can be applied as part of a Power-to-Gas (PtG) concept to store renewable electricity. Using a catalytic bubbling fluidized bed (BFB) methanation reactor allows a flexible and economic operation. Properties of bubbles rising through the fluidiz ...

EPFL2022

Medipix4, a high granularity four sides buttable pixel readout chip for high resolution spectroscopic X-ray imaging at rates compatible with medical CT scans

Viros Sriskaran

Medipix4 is the latest member in the Medipix/Timepix family of pixel detector chips aimed at high rate spectroscopic X-ray imaging using high-Z materials. The chip address the limitations of conventional hybrid pixel detectors for X-ray imaging. Its predec ...

EPFL2022

Learning to sample in Cartesian MRI

Thomas Sanchez

Magnetic Resonance Imaging (MRI) is a non-invasive, non-ionizing imaging modality with unmatched soft tissue contrast. However, compared to imaging methods like X-ray radiography, MRI suffers from long scanning times, due to its inherently sequential acqui ...

EPFL2022

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials. Part II: Experimental verification of modelling approaches by infiltration of Si-Zr alloy into idealized microchannels

Ludger Weber, Giovanni Bianchi, Alberto Ortona, Manoj Kondibhau Naikade, Caroline Hain

In this work, the mechanisms leading to the pore closure in reactive melt infiltration (RMI) of carbon by pure silicon and a near eutectic Si-8 at-pct Zr alloy at 1500 and 1700 degrees C under vacuum were studied. Various geometrical configurations of micr ...

ELSEVIER SCI LTD2022

Insights into the interaction of a shale with CO2

Lyesse Laloui, Eleni Stavropoulou

Caprock formations, such as shales, play a key role in safe underground CO2 storage since they serve as a hydromechanical barrier that prevents migration of the injected CO2 to the surface. While their hydromechanical response is important to ensure their ...

2022

The new X-ray/visible microscopy MAXWELL technique for fast three-dimensional nanoimaging with isotropic resolution

Giorgio Margaritondo, Lin Yang

Microscopy by Achromatic X-rays With Emission of Laminar Light (MAXWELL) is a new X-ray/visible technique with attractive characteristics including isotropic resolution in all directions, large-volume imaging and high throughput. An ultrathin, laminar X-ra ...

Nature Portfolio2022

Lock-in amplified differential phase contrast

Christophe Moser, Damien Claude-Marie Loterie, Timothé Laforest, Chiara Bonati

We introduce a lock-in method to increase the phase contrast in incoherent Differential Phase Contrast (DPC) imaging. The use of a smart pixel detector with in-pixel signal demodulation, paired with synchronized illumination, provides the basis of a bit-ef ...

SPIE-INT SOC OPTICAL ENGINEERING2022

High sensitivity, incoherent differential imaging

Chiara Bonati

Microscopic visualisation of optically transparent samples has been a topic of interest for several decades. Features such as density or chemical composition can influence the optical phase of transmitted light, and phase contrast can reveal these structur ...

EPFL2022

Stain-free identification of cell nuclei using tomographic phase microscopy in flow cytometry

Demetri Psaltis, Joowon Lim, Daniele Pirone

The accurate identification of the three-dimensional quantitative shape of a cell nucleus is now possible without fluorescent staining by applying computational segmentation to refractive index tomograms recorded in the flow cytometry mode. ...

Nature Publishing Group2022

Advanced Techniques in Optical Diffraction Tomography

Ahmed Bassam Sayed Ayoub Mohamed Emam

In this thesis, we study the 3 challenges described above. First, we study different reconstruction techniques and assess the fidelity of each reconstruction results by means of structured illumination and phase conjugation. By reconstructing the 3D refrac ...

EPFL2022