Publications by authors named "R Letrun"
We report on recent developments that enable megahertz hard X-ray phase contrast imaging (MHz XPCI) experiments at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument of the European XFEL facility (EuXFEL). We describe the technical implementation of the key components, including an MHz fast camera and a modular indirect X-ray microscope system based on fast scintillators coupled through a high-resolution optical microscope, which enable full-field X-ray microscopy with phase contrast of fast and irreversible phenomena. The image quality for MHz XPCI data showed significant improvement compared with a pilot demonstration of the technique using parallel beam illumination, which also allows access to up to 24 keV photon energies at the SPB/SFX instrument of the EuXFEL.
View Article and Find Full Text PDFX-ray multi-projection imaging (XMPI) is an emerging experimental technique for the acquisition of rotation-free, time-resolved, volumetric information on stochastic processes. The technique is developed for high-brilliance light-source facilities, aiming to address known limitations of state-of-the-art imaging methods in the acquisition of 4D sample information, linked to their need for sample rotation. XMPI relies on a beam-splitting scheme, that illuminates a sample from multiple, angularly spaced viewpoints, and employs fast, indirect, X-ray imaging detectors for the collection of the data.
View Article and Find Full Text PDFArticle Synopsis
- Scientists have found a new way to see tiny changes in proteins very quickly, which is important for biology and medicine.
- They used special X-ray lasers that can take pictures millions of times a second without much background noise.
- This new method helps them study how proteins unfold and change shape, making it useful for understanding many different biological processes.
Article Synopsis
- Nanoparticles with varied structures are a major focus in research, and new techniques like high-throughput single-particle imaging (SPI) with X-ray free-electron lasers (XFELs) are now enabling the analysis of millions of these particles.
- To effectively utilize this technology, researchers faced three key challenges: understanding structural variability, extracting relevant parameters from measurements, and comparing multiple structural models to the data collected.
- By addressing these challenges, scientists mapped the diverse shapes of gold nanoparticles, revealing important insights into their asymmetry, stable shape patterns, and how external factors like surfactants influence their structure, making nanoparticle characterization more reliable.
Article Synopsis
- The main protease (M) of SARS-CoV-2 is crucial for the virus's functionality and is considered a potential target for drug development, as it is only active in its reduced form.
- When oxidized, M's activity halts but can be restored, indicating an evolutionary adaptation to oxidative environments, although the protective mechanisms haven't been fully elucidated.
- Researchers determined the crystal structure of oxidized M, revealing a disulfide bond that affects its dimer stability and crystallization, providing insights into the protein's response to oxidative stress and its structural study conditions.*