Pourquoi le Covid-19 frappe si durement les personnes âgées
Plus on est âgé, plus le risque de mourir d’une infection au coronavirus est élevé. G. V. Shivashankar, chef d’un groupe de recherche au PSI et professeur à l’ETH Zurich, vient de présenter une thèse surprenante dans le cadre d’une publication dans la revue «Nature Reviews»: la rigidité des cellules jouerait un rôle décisif dans l’évolution de la maladie. Dans cet entretien, il explique pourquoi.
«Dans la lutte contre le virus, chaque jour compte»
La pratique de la recherche au PSI a changé depuis le début de la pandémie de coronavirus, mais elle n’est pas à l’arrêt. Gabriel Aeppli, chef de la division de recherche Sciences photoniques au PSI, évoque la menace particulière que représente le Covid-19, de même que la manière dont des chercheurs du PSI étudieront ce nouveau virus à la SLS et l’étudieront sans doute bientôt au SwissFEL également.
La recherche prioritaire se poursuit
En raison de la pandémie de Covid-19, l’Institut Paul Scherrer PSI a restreint son activité et, conformément aux directives du Conseil fédéral, la plupart des collaborateurs font du télétravail. Les installations et les projets de recherche indispensables, en revanche, continuent à fonctionner toujours dans le respect de l’ensemble des mesures de sécurité requises.
«Notre objectif est de comprendre comment fonctionne ce virus»
Malgré la pandémie de Covid-19, la Source de Lumière Suisse SLS est toujours en service et, en cette période difficile, il se pourrait bien que l’on en ait urgemment besoin. Oliver Bunk, chef du Laboratoire de macromolécules et de bio-imagerie, nous explique pourquoi.
«La stratégie et le réseautage revêtent une importance énorme»
Gebhard Schertler dirige la division de recherche Biologie et Chimie au PSI et est professeur de biologie structurale à l’ETH Zurich. Il décrit le type de recherche menée au PSI sur le coronavirus et souligne l’importance de la coopération avec des chercheurs d’autres institutions.
«La SLS est actuellement quelque chose de très spécial dans toute l’Europe»
En cette période de pandémie, la Source de Lumière Suisse SLS est l’une des rares sources de rayonnement synchrotron à être encore en service en Europe. Mirjam van Daalen, cheffe d’état-major de la division de recherche Sciences photoniques, souligne dans cet entretien à quel point la collaboration internationale est importante à l’heure actuelle.
Détecter les sources radioactives dans le transport de marchandises
Le PSI opère régulièrement des contrôles de radioactivité sur des camions à l’aide d’un portique de détection mobile, sur mandat de l’Office fédéral de la santé publique. Sa mission: détecter les sources de radiation orphelines.
Examining the surface evolution of LaTiOxNy an oxynitride solar water splitting photocatalyst
LaTiOxNy oxynitride thin films are employed to study the surface modifications at the solid- liquid interface that occur during photoelectrocatalytic water splitting. Neutron reflectometry and grazing incidence x-ray absorption spectroscopy were utilised to distinguish between the surface and bulk signals, with a surface sensitivity of 3 nm.
Microcalcifications in breast tissue: Paving the way for future diagnostic solutions?
Microcalcifications are a common sign in mammography. For example, in 90% of ductal carcinoma in situ microcalcifications are the first and unique sign indicating the presence of the lesion. Nevertheless, up to around 50% of the resulting biopsies reveal a benign lesion, a 'false positive'. Researchers were able to show now that breast microcalcifications detected in tumors have specific chemical and crystalline features different from those observed in benign samples. Moreover, microcalcifications detected in tumors but located outside the lesion show malignant features too. This indicates that cancer influences the surrounding tissue even if it exhibits apparently healthy morphological features. These results indicate that the biochemical differences between benign and malignant microcalcifications can be potentially identified by light-based tools, able to investigate microcalcifications inside the breast without performing biopsies.
Information for CHRISP users
Because of the present coronavirus situation, preparations for the startup of the proton accelerator HIPA are currently suspended since March 16. At that point in time, there were still about 8 weeks to finalize the shutdown work.
Home Office der Lernenden Chemielaboranten während Coronavirus
Mit den folgenden Beiträgen wollen wir Ihnen zeigen, welche Projekte die Chemielaboranten während dem Home Office erarbeitet haben. Zudem wollen wir Ihnen auch veranschaulichen, dass Chemie überall in unserem Alltag anzutreffen ist.
Le professeur Christian Rüegg est le nouveau directeur de l’Institut Paul Scherrer
Le nouveau directeur de l'Institut Paul Scherrer entre en fonction aujourd'hui: Christian Rüegg veut continuer à développer la position de leader des grandes installations de recherche du PSI et ainsi renforcer la Suisse en tant que site de recherche.
Rapid 3D directional small-angle scattering imaging achieved at TOMCAT
Researchers from the TOMCAT beamline have developed a small-angle scattering tensor tomography method to visualize microscopic features within a macroscopic field of view with unprecedented data acquisition speed. The results of the study were published in Applied Physics Letters on April 1, 2020.
Rapid 3D directional small-angle scattering imaging achieved at TOMCAT
Researchers from the TOMCAT beamline have developed a small-angle scattering tensor tomography method to visualize microscopic features within a macroscopic field of view with unprecedented data acquisition speed. The results of the study were published in Applied Physics Letters on April 1, 2020.
SLS MX beamtime update
Update of the SLS MX beamline operation during the COVID-19 period
Elucidating the Oxygen Activation Mechanism on Ceria-Supported Copper-Oxo Species Using Time-Resolved X-ray Absorption Spectroscopy
We monitored the dynamic structure of the active sites in a catalyst containing highly dispersed copper-oxo species on ceria during low-temperature CO oxidation using time-resolved X-ray absorption spectroscopy. We quantitatively demonstrate that the CO oxidation mechanism below 90 °C involves an oxygen intermediate strongly bound to the active sites as well as the redox activity of Cu2+/Cu+ and Ce4+/Ce3+ couples.
SNF funds dynamic X-ray imaging of the human auditory system in motion
In collaboration with clinicians from the Inselspital and engineers of the University Hospital of Bern, the X-Ray Tomography Group will be part of a new SNF project entitled “The Human Auditory System in Motion: Direct Observation of the Microfunction of Sound Transmission using Dynamic Phase-contrast X-ray Imaging”.
Electron–phonon-driven three-dimensional metallicity in an insulating cuprate
Elucidating the role of different degrees of freedom in a phase transition is crucial in the comprehension of complex materi- als. A phase transformation that attracts significant interest is the insulator-to-metal transition of Mott insulators, in which the electrons are thought to play the dominant role. Here, we use ultrafast laser spectroscopy and theoretical calculations ....
Spin ice expands to higher orders
With experimental work demonstrating that the correlated ground state of the pyrochlore system Ce2Sn2O7 is a quantum liquid of magnetic octupoles, an international team led by PSI researcher Romain Sibille establishes a fundamentally new state of matter: higher-rank multipole ice.
Spin ice expands to higher orders
With experimental work demonstrating that the correlated ground state of the pyrochlore system Ce2Sn2O7 is a quantum liquid of magnetic octupoles, an international team led by PSI researcher Romain Sibille establishes a fundamentally new state of matter: higher-rank multipole ice.
X-ray Imaging for Biomedicine: Imaging Large Volumes of Fresh Tissue at High Resolution
The TOMCAT beamline at the Swiss Light Source specializes in rapid high-resolution 3-dimensional tomographic microscopy measurements with a strong focus on biomedical imaging. The team has recently developed a technique to acquire micrometer-scale resolution datasets on the entire lung structure of a juvenile rat in its fresh natural state within the animal’s body and without the need for any fixation, staining or other alteration that would affect the observed structure (E. Borisova et al., 2020, Histochem Cell Biol).
A quantum liquid of magnetic octupoles on the pyrochlore lattice
With experimental work demonstrating that the correlated ground state of the pyrochlore system Ce2Sn2O7 is a quantum liquid of magnetic octupoles, an international team led by PSI researcher Romain Sibille establishes a fundamentally new state of matter: higher-rank multipole ice.
15th International Conference on Muon Spin Rotation postponed to 2021
Because of the coronavirus situation, the 15th International Conference on Muon Spin Rotation, Relaxation and Resonance (µSR2020) has been postponed to 2021. More details will be announced in due time.
Reversible spin storage in metal oxide - fullerene heterojunctions
We show that hybrid MnOx/C60 heterojunctions can be used to design a storage device for spin-polarized charge: a spin capacitor. Hybridization at the carbon-metal oxide interface leads to spin-polarized charge trapping after an applied voltage or photocurrent. Strong electronic structure changes, including a 1-eV energy shift and spin polarization in the C60 lowest unoccupied molecular orbital, are then revealed by x-ray absorption spectroscopy, in agreement with density functional theory simulations.
Logic operations with domain walls
A collaboration of scientists from the ETH Zürich and the Paul Scherrer Institute successfully demonstrated the all-electric operation of a magnetic domain-wall based NAND logic gate, paving the way towards the development of logic applications beyond the conventional metal-oxide semiconductor technology. The work has been published in the journal Nature.
SwissFEL: Athos fait de grands progrès
La nouvelle ligne de faisceaux à rayons X au laser à électrons libres SwissFEL du PSI sera bientôt opérationnelle. En décembre, Athos a fourni pour la première fois de la lumière laser, même plus tôt que prévu, à la grande joie des chercheurs en charge de sa construction.
Optics for spins
In this work, published on the front cover page of Advanced Materials, an international collaboration of Italian, American, and Swiss scientists demonstrated a novel concept for the generation and manipulation of spin waves, paving the way towards the development of magnonic nano-processors.
Can skyrmions read?
Can a skyrmion-based device be used to read a handwritten text? In this work, an international scientist collaboration led by the Korea Institute of Technology and the IBM Watson research center could provide a first answer to this question by fabricating a proof-of-principle single-neuron artificial neural network, using X-ray magnetic microscopy at the Swiss Light Source to investigate its performances.
Pour la première fois, des réactions chimiques ont été observées directement dans les particules fines
Des chercheurs de l’Institut Paul Scherrer PSI ont développé une nouvelle méthode pour analyser les particules fines de manière encore plus détaillée. Elle leur a permis de réfuter la doctrine selon laquelle les molécules contenues dans les poussières fines ne subissent plus de réactions chimiques parce qu’elles font partie de la phase condensée.
Quantifying Diffusion through Interfaces of Lithium-Ion Battery Active Materials
Detailed understanding of charge diffusion processes in a lithium-ion battery is crucial to enable its systematic improvement. Experimental investigation of diffusion at the interface between active particles and the electrolyte is challenging but warrants investigation as it can introduce resistances that, for example, limit the charge and discharge rates. Here, we show an approach to study diffusion at interfaces using muon spin spectroscopy.