Videos
Electron Paramagnetic Resonance Advancing MAS-DNP
During the 88th session of the Global NMR Discussion Meetings held on October 1st, 2024 via Zoom, Dr. Frédéric Mentink-Vigier from the National High Magnetic Field Laboratory, Florida, US gave a talk on the topic "Electron Paramagnetic Resonance Advancing Magic Angle Spinning Dynamic Nuclear polarization". The recording serves as a tutorial.
Abstract: Electron Paramagnetic Resonance (EPR) is crucial for analyzing paramagnetic species used in Dynamic Nuclear Polarization (DNP). This overview covers EPR fundamentals and its application to studying biradicals, which are key for high-field Magic Angle Spinning (MAS) DNP.
Find out more about Dr. Frédéric Mentink-Vigier's work: https://nationalmaglab.org/staff/?name=FredericMentink-vigier
Triplet Dynamic Nuclear Polarization
During the 66th session of the Global NMR Discussion Meetings held on May 2nd, 2023 via Zoom, Prof. Nobuhiro Yanai gave a talk on the topic "Triplet Dynamic Nuclear Polarization: New Polarizing Agents and Targets". The recording serves as a tutorial.
Abstract:
Triplet dynamic nuclear polarization (triplet-DNP), which utilizes the polarized electron spins of the photo-excited triplet, is an excellent method to obtain large nuclear spin polarization even under mild conditions below 1 T near room temperature. This talk will highlight the potential of triplet-DNP and the exciting new possibilities that have emerged with recent advancements in polarizing agents and targets. Specifically, I will cover the following topics:
- Mechanism of triplet-DNP as an introduction
- Expanding the targets using supramolecular polarizing agents
- Improving air stability and solubility with non-pentacene polarizing agents
- Challenging polarization transfer with the use of nanomaterials.
Nobuhiro Yanai is an Associate Professor, Department of Chemistry and Biochemistry, Kyushu University, Japan.
Website: https://sites.google.com/view/nobuhiroyanai/
Google scholar: https://scholar.google.com/citations?...
Twitter: https://twitter.com/nobuhiroyanai?lang=en
Surprising Consequences of High Electron Spin Polarization
During the 59th session of the Global NMR Discussion Meetings held on January 10th, 2023 via Zoom, Dr. Quentin Chappuis Stern gave a talk on the topic "The surprising consequences of near unity electron spin polarization". The recording serves as a tutorial.
Abstract:
The inherent low sensitivity of NMR can be overcome by hyperpolarization techniques, which increase the polarization of nuclear spins far beyond the Boltzmann equilibrium. One such method is dynamic nuclear polarization (DNP), which consists of transferring the high polarization of unpaired electron spins to surrounding nuclear spins via microwave irradiation. In the case of dissolution DNP (dDNP), the sample is hyperpolarized in the solid state at low temperature (1-2 K) and moderate magnetic field (3-7 T), where the Boltzmann polarization of electron spins approaches unity, translating into equally high nuclear polarization under DNP. In addition to yielding high nuclear polarization, the high electron polarization has other interesting consequences for NMR. Indeed, as the electron polarization tends towards unity, the electron flip-flop probability vanishes, an effect sometimes referred to as “bath quenching”. By switching on and off microwave irradiation (microwave gating), one switches on and off electron flip-flops and hence paramagnetic relaxation. This has been shown to have a dramatic effect on transverse nuclear relaxation and on nuclear spin diffusion. In this talk, I will review the basic concepts of paramagnetic relaxation and its dependence on electron polarization. I will then present experiments where we used microwave gating to perform efficient CP, to detect EPR properties indirectly via NMR properties, and finally to study nuclear spin diffusion in the vicinity of electron spins.
Speaker's biography:
2014- Undergraduate and Masters, EPFL (Switzerland). Thesis with Prof. Bodenhausen
2022- PhD, CRMN Lyon (France), with Prof. Sami Jannin
Follow Dr. Stern's work here:
Twitter: https://twitter.com/quentinchapp
Google scholar: https://scholar.google.fr/citations?u...
Room Temperature DNP via P1 Centers in Diamond
During the 58th session of the Global NMR Discussion Meetings held on December 14th, 2022 via Zoom, Prof. Chandrasekhar Ramanathan from Dartmouth College, USA , gave a talk on the topic "Room Temperature DNP via substitutional-nitrogen (P1) centers in diamond". The recording serves as a tutorial.
Abstract:
Electron spins in diamond have long coherence and relaxation times at room temperature, making them an exciting platform for EPR and DNP experiments under ambient conditions. In this talk I will describe our recent W-band DNP experiments using the substitutional nitrogen (or P1) defect to hyperpolarize the 13C spins in both single crystal and diamond powders. The DNP spectra measured in these samples show signatures of multiple mechanisms including the solid effect, the cross effect, the truncated cross effect and the Overhauser effect. I will discuss how variations in the microscopic environments of the spins could lead to these observations.
Follow Prof. Ramanathan's work here:
Twitter: https://twitter.com/sekharspins
Google scholar: https://scholar.google.com/citations?...
Website: https://sites.dartmouth.edu/quantum-s...
EPR-NMR for Protein Modeling
During the 57th session of the Global NMR Discussion Meetings held on November 29th, 2022 via Zoom, Prof. Gunnar Jeschke from ETH Zurich, gave a talk on the topic "Integrating EPR distance distribution restraints with NMR data in protein models". The recording serves as a tutorial.
Abstract:
This zoominar will start with a short explanation of in silico spin labelling, which is useful for planning paramagnetic relaxation enhancement (PRE) NMR experiments as well as DEER EPR experiments for measuring distance distributions. I will continue with a primer on converting DEER data into distance distributions. The zoominar concludes with an example of using distance distributions in modelling a weakly structured low-complexity domain of an RNA-binding protein.
Speaker's biography:
1993-1996 PhD at ETH Zurich, Switzerland, with A. Schweiger
1998-2006 Group Leader, Max Planck Institute for Polymer Science in Mainz, Germany, with H. W. Spiess
2006-2008 Professor at the University of Konstanz, Germany
2008- Professor at ETH Zurich
Follow Prof. Jeschke's work here:
Website: https://epr.ethz.ch/
Dual NMR-EPR Detection in an Ultra Low Temperature DNP Spectrometer
During the 37th session of the Global NMR Discussion Meetings on Zoom, Kan Tagami, University of California, Santa Barbara (UCSB), gave a talk on the instrumentation aspects of a dynamic nuclear polarization spectrometer with dual nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) detection at ultra-low temperatures.
Speaker's biography:
2012 - 2016: B.S., Chemistry, College of William and Mary, USA.
2016 - present: Graduate Student Researcher, Chemistry, University of California - Santa Barbara, USA (Advisor: Prof. Songi Han)
Kan's research interest is in the spin physics and instrumentation of dynamic nuclear polarization (DNP) in solid state NMR. His goal is to improve the efficiency of solid state DNP under MAS through development of both EPR and NMR instruments, as well as use a wide variety of existing magnetic resonance techniques to characterize and exploit the underlying mechanisms of DNP. Currently, his focus is on development of a low temperature (30K), high field (7T) pulsed EPR/DNP spectrometer with magic angle spinning capabilities.
For more information, see the Han Lab website: https://han.chem.ucsb.edu
Frequency-Agile Instrumentation for High Field DNP/EPR Spectroscopy
The 19th session of the Global NMR Discussion Meeting was held on 24th November 2020 via Zoom. Dr. Thorsten Maly gave a talk on versatile, frequency-agile instrumentation for high field dynamic nuclear polarization/electron paramagnetic resonance spectroscopy. The video was recorded live during the presentation and serves as an educative lecture. Bio: 2005 Ph.D. in Chemistry, JWG University Frankfurt, Germany (group of Prof. Thomas Prisner) 2005-2010 Postdoc, MIT, Cambridge, USA (group of Prof. Bob Griffin) 2010-present: co-founder Bridge12 Technologies, Inc., Framingham USA
Follow Thorsten on social media:
Twitter: @thmaly
Website: http://www.bridge12.com/thorsten-maly/
Google Scholar: https://scholar.google.com/citations?...
Research Gate: https://www.researchgate.net/profile/...
Abstract: To further improve the DNP methodology it is crucial to understand the EPR properties of the DNP sample at the field of the DNP experiment. However, gyrotron-based DNP system only offer limited flexibility to extract EPR parameters. In this tutorial, I will review frequency-agile instrumentation suitable for high-frequency DNP and EPR spectroscopy. I will discuss strategies for generating and detecting microwave radiation and will present the fundamental basics of quasi- optics, necessary to separate the incident from the reflected microwave beam.
Basics of EPR for NMR Spectroscopists
The 16th session of the Global NMR Discussion Meeting was held on 13th October 2020 via Zoom. Nino Wili gave a talk on the basics of electron paramagnetic resonance (EPR) for nuclear magnetic resonance (NMR) spectroscopists. The video was recorded live during the presentation and serves as an educative lecture.
Nino's slides are also available for download here: https://drive.google.com/file/d/1rKYL...
Nino received his M.Sc. from Prof. Matthias Ernst's group at ETH Zürich in 2016. He is currently a Ph.D. student in Prof. Gunnar Jeschke's group at ETH Zürich.
Follow Nino on Twitter: @ChirpDontTweet
Google scholar page: https://scholar.google.ch/citations?u...