We warmly invite you to participate in a new series of scientific seminars organised by the User Office at MAX IV, Lund University
Where – Virtual format by Zoom call https://lu-se.zoom.us/j/61349123545
When – Mondays 13:45 CET
Format – 30 minutes of presentation followed by 15 minutes of discussion, chaired by MAX IV staff
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Monday 27 September 2021, 13:45 CET
Combined use of photons, neutrons, and electrons to unravel molecular details of the myelin membrane
Speaker: Prof Petri Kursula, Department of Biomedicine, University of Bergen, Norway
Host: Dr Tomás Plivelic, manager at CoSAXS beamline
Keywords: self-assembling repetitive molecular assemblies, myelin, biophysics, structural biology
Biological structures with self-assembling repetitive molecular assemblies are intriguing subjects for structural biology research. But how do such biostructures form and function at the molecular level? My model system is myelin, a tightly packed multilayer important for the normal functioning of the vertebrate nervous system. Myelin consists of dozens of proteolipid membrane layers, wrapped by a glial cell around the axon, and myelin-specific proteins are directly involved in binding of myelin membranes together. Our research focuses on the structure and properties of myelin-like membrane multilayers at different levels of detail. We use a combination of techniques, ranging from biophysics to structural biology, and experiments at large-scale research infrastructures are crucial for the project. I will describe the molecular structure of the myelin membrane and discuss our recent results and future plans with regard to more detailed studies on the molecular properties of myelin. Such information will be crucial for understanding both the molecular biology of myelin formation as well as mechanisms of demyelinating disease.
Monday 4 October 2021, 13:45 CET
Joint x-ray and neutron crystallography: similarities and differences between these complementary techniques
Speaker: Dr Suzanne Zoë Fisher, Group Leader Deuteration and Macromolecular Crystallization (DEMAX) Platform, European Spallation Source ERIC, Sweden
Host: Ana González, manager at BioMAX beamline
Keywords: Neutrons and X-rays, protein structures, single crystal Bragg diffraction
Neutrons and X-rays are complementary and powerful probes for the study of complex protein structures – from looking at active site residue geometry and electrostatics to understanding the atomic details of ligand binding. While the methods are complementary and based on the same principle (i.e. single crystal Bragg diffraction) the realities and practicalities of making it all work together are very different. In this talk I will explain the workflow and timelines typically involved – from sample needs, data collection possibilities, to flexible beamline support. It is not widely known that a key part of solving and interpreting neutron protein crystal structures is the availability of x-ray diffraction data for the same system/crystal. Putting all the pieces together to enable the user to obtain a high quality and meaningful structure remains a challenge. There can be quite a disconnection between where and when neutron data is obtained and where and when x-ray data is obtained. If the relevant beamlines at ESS and MAX lab can figure out a way to offer integrated support to MX users, that would be a significant step forward in the field.
Monday 11 October 2021, 13:45 CET
Direct visualisation of nano-particle aggregation and retention inside porous media
Speaker: Dr Henning Osholm Sørensen, Senior Researcher, Department of Physics, Technical University of Denmark
Host: Dr Innokenty Kantor, manager at DANMAX beamline
Keywords: X-ray tomography, nanoparticles, porous media, environmental remediation
Engineered nanoparticles are increasingly being used for different applications. Over time they will be released into the environment. Some of the engineered nanoparticles are developed and introduced into the environment on purpose in order to perform e.g. remediation of soils contaminated by chlorinated organic compounds. Whether realised consciously or unintentionally introduced to the environment they can constitute an environmental risk. Therefore, we need to understand, and in turn be able to predict, the fate of the nanoparticles hereunder how they are transported and retained in porous media. Currently, very little is known about the basic processes involved in retaining nanoparticles during transport in porous media. We have, recently, started to study these processes that occur when injecting sulfidised zerovalent iron nanoparticles (S-nZVI) into porous media. We image the nanoparticles retained in porous sands directly at various stages and under different injection conditions. Here, we will present the first results showing the feasibility of studying nanoparticle retention mechanisms in porous materials using X-ray tomography and some outline some future ideas of using DanMAX at MAX-IV to perform in situ 3D imaging at different scales.
Monday 18 October 2021, 13:45 CET
Molecular dissociation following x-ray absorption – how can we know, what happened during the crucial early stages
Speaker: Prof Edwin Kukk, Head of Materials Research Laboratory, University of Turku, Finland
Host: Dr Antti Kivimäki, manager at FinEstBeAMS beamline
Keywords: organic and biomolecules, X-ray absorption, molecular dissociation
X-ray ionization of organic and biomolecules is a process that is both of fundamental interest and of practical relevance for example in cancer treatment. The molecule is usually destroyed after x-ray absorption, but the mechanisms and factors that determine the eventual outcome of the dissociation – the fragment patterns and energies – is far from fully understood. Advanced spectroscopic techniques such as momentum imaging ion mass spectroscopy and various coincidence measurements, performed at synchrotrons and free electron lasers have greatly advanced our knowledge in this area. Particularly the femtosecond-scale pump-probe experiments have recently provided rare insights into the first tens and hundreds of femtoseconds following the photoionization.
We present examples on such studies at the SACLA free electron laser and at the recently commissioned Gas Phase Endstation of FinEstBeams beamline at MAX IV. They demonstrate that these two types of x-ray sources are complementary and their combined use helps to form a much more complete understanding of the complex quantum mechanical processes in the early stages of the x-ray induced molecular dissociation. In particular, recent MAX-lab results on the photodissociation of tetrabromothiophene and di-iodothiophene are presented, and it is discussed how synchrotron radiation, even though not inherently offering femtosecond-scale time-resolved capabilities, nevertheless provides very valuable clues on the early molecular dynamics.
Monday 25 October 2021, 13:45 CET
No SCIENTÌFika session. We warmly invite you to attend our annual User Meeting.
Monday 1 November 2021, 13:45 CET
Chemical bonding of termination species in 2D carbides investigated through valence band UPS/XPS of Ti3C2Tx MXene
Speaker: Dr Lars-Åke Näslund, Senior Research Engineer, Department of Physics, Chemistry and Biology (IFM), Linköping University, Sweden
Host: Dr Esko Kokkonen, manager at SPECIES beamline
Monday 15 November 2021, 13:45 CET
Speaker: Dr Denis V. Vyalikh, Research Professor at Donostia International Physics Center (DIPC), Spain
Host: Dr Craig Polley, manager at BLOCH beamline
Monday 13 December 2021, 13:45 CET
Ultrafast interatomic processes investigated by electron-photon coincidence spectroscopy
Speaker: Dr Andreas Hans, Leading scientist, Experimental Physics, University of Kassel, Germany
Host: Dr Noelle Walsh, scientist at FlexPES beamline
Keywords: charge and energy transfer mechanisms, radiation biology, optical photons in multi-electron coincidence spectroscopy
The investigation of prototypical atomic and molecular clusters is an important step towards understanding the response of real-life matter to the exposure to ionizing radiation. Ever since the prediction of interatomic Coulombic decay (ICD) in 1997, a family of interatomic and intermolecular charge and energy transfer mechanisms has been identified to act in weakly bound matter upon VUV or X-ray photoionization. Their role in radiation biology and other fields is lively debated. I will report on recent progress and future perspectives in tracking and characterizing such processes by including optical photons in multi-electron coincidence spectroscopy.
The initiative aims to share knowledge and stimulate enthusiastic discussions on synchrotron research and methods developed at MAX IV. These shall be a channel to learn more about our facility, strengthen collaborations, bring communities together and promote cooperation and interdisciplinarity.
The speakers will be MAX IV past, current and potential future users, as well as MAX IV staff; on the other hand, welcome attendees are members of the broad scientific community: scientists from the speaker´s home institution, of Swedish and international universities as well as MAX IV and other light sources staff.
We look forward to seeing you online and hope you enjoy the talks!
name Doriana Orbanic