Author Archives: tmaly

[NMR] Postdoc position on DNP/RF instrumentation at ENS Paris #DNPNMR

Hi all,
There is a postdoc position available in Kong Ooi Tan’s team at ENS Paris starting in spring 2021. Initial contract is for one year, and renewable at the end of each contract year. The main goal of the project is to develop rf and microwave instrumentation for Dynamic Nuclear Polarization (DNP) techniques at high magnetic fields, i.e., ≥ 9.4 T/ 400 MHz/ 263 GHz. The candidate needs to build a DNP NMR probe with optimized rf & microwave delivery from the source to the sample at a cryogenic condition. The array of instruments that has to be built includes microwave waveguides, resonant cavity, and rf resonance circuitry. Hence, candidates with experience in assembling rf and microwave components is highly desirable. Besides, we will build a low-cost EPR circuitry in the same probe to allow the characterization of the DNP polarizing agents using EPR spectroscopy. Our lab houses an 800 MHz/ 527 GHz MAS-DNP spectrometer, a 600 MHz, a 400 MHz, and two dissolution-DNP polarizers (a Bruker prototype at 6.7 T/ 188 GHz and a home-built cryogen-free system at 9.4 T/ 263 GHz).
More details are available at https://euraxess.ec.europa.eu/jobs/590039Group website: http://www.paris-en-resonance.fr
Feel free to circulate the advertisement to whoever might be interested in this position.
Thank you for your time and happy holidays!
Regards,Kong

Prof. Kong Ooi Tan
Junior ProfessorLaboratoire des Biomolécules UMR 7203 
Département de Chimie
École Normale Supérieure 24 Rue Lhomond 
75231 Paris CEDEX 05
Université PSLhttp://www.paris-en-resonance.fr

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[NMR] Solid-State NMR Service Manager position at Durham University (UK)

Dear colleagues,

In preparation for the retirement of the current manager, we are looking for an experienced solid-state NMR practitioner to run the Durham Solid-State NMR Research Service (https://www.dur.ac.uk/solid.service/).

As well as supporting academic research, primarily for the Department of Chemistry, and particularly for the NMR research groups of Dr Karen Johnston and Prof. Paul Hodgkinson, the Service is essentially self-financing through commercial service work to industry and academia more widely. Maintaining and developing this business model will be key to renewal of the post beyond the initial two year appointment period.

Full details about the position and how to apply can be found here:

https://durham.taleo.net/careersection/du_ext/jobdetail.ftl?job=20000850

[Apologies for the excessive length of the HR-imposed application process – ability to identify the important material is the first selection criterion!]

The closing date is 24 Jan.

With good wishes,

Paul Hodgkinson

Karen Johnston
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Selective NMR observation of the SEI–metal interface by dynamic nuclear polarisation from lithium metal #DNPNMR

Hope, Michael A., Bernardine L. D. Rinkel, Anna B. Gunnarsdóttir, Katharina Märker, Svetlana Menkin, Subhradip Paul, Ivan V. Sergeyev, and Clare P. Grey. “Selective NMR Observation of the SEI–Metal Interface by Dynamic Nuclear Polarisation from Lithium Metal.” Nature Communications 11, no. 1 (December 2020): 2224.

https://doi.org/10.1038/s41467-020-16114-x

While lithium metal represents the ultimate high-energy-density battery anode material, its use is limited by dendrite formation and associated safety risks, motivating studies of the solid–electrolyte interphase layer that forms on the lithium, which is key in controlling lithium metal deposition. Dynamic nuclear polarisation enhanced NMR can provide important structural information; however, typical exogenous dynamic nuclear polarisation experiments, in which organic radicals are added to the sample, require cryogenic sample cooling and are not selective for the interface between the metal and the solid–electrolyte interphase. Here we instead exploit the conduction electrons of lithium metal to achieve an order of magnitude hyperpolarisation at room temperature. We enhance the 7Li, 1H and 19F NMR spectra of solid–electrolyte interphase species selectively, revealing their chemical nature and spatial distribution. These experiments pave the way for more ambitious room temperature in situ dynamic nuclear polarisation studies of batteries and the selective enhancement of metal–solid interfaces in a wider range of systems.

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Dipolar nuclear polarization via the spin diffusion of a dipole order #DNPNMR

Furman, G.B., S.D. Goren, V.M. Meerovich, and V.L. Sokolovsky. “Dipolar Nuclear Polarization via the Spin Diffusion of a Dipole Order.” Journal of Magnetic Resonance 320 (November 2020): 106847.

https://doi.org/10.1016/j.jmr.2020.106847

We propose transfer of the paramagnetic impurity (PI) polarization to nuclei in bulk, outside the diffusion barrier, by using dipolar system of the nuclear spins. The transfer can overcome influence of the diffusion barrier and is proposed to be implemented in four stages. At the first stage, transition of the Zeeman PI order to the Zeeman order of nuclear spins inside the spin-diffusion barrier is occurred. During the second stage the Zeeman order of both the nuclear spins inside the barrier and the nuclear spins in bulk is transferred into the nuclear dipolar spin order. As a result, the nuclear dipolar spin reservoir inside the barrier acquires a lower spin temperature, and thus a gradient of the spin temperature of the nuclear dipolar spin system is created. Since the external magnetic field and the magnetic field created by PIs do not effect on the dipole-dipole interaction between the nuclear spins, the dipolar reservoir is common for all nuclear spins, both inside and outside the diffusion barrier. Restriction of the diffusion barrier is removed and the spin diffusion of the dipole energy and transfer of the spin dipolar order to bulk spins occurs without obstacles (the third stage). At the last stage, to register an NMR signal, the dipolar order of the bulk spins is transferred into the Zeeman order of these spins. Estimations show that enhancement of the polarization can reaches in the case of a 1H nuclear spin, ~220, for 13C ~850, and for 15N ~2130.

Scalable microresonators for room-temperature detection of electron spin resonance from dilute, sub-nanoliter volume solids

This article is about microresonators for EPR Spectroscopy.

Abhyankar, Nandita, Amit Agrawal, Pragya Shrestha, Russell Maier, Robert D. McMichael, Jason Campbell, and Veronika Szalai. “Scalable Microresonators for Room-Temperature Detection of Electron Spin Resonance from Dilute, Sub-Nanoliter Volume Solids.” Science Advances 6, no. 44 (October 2020): eabb0620

https://doi.org/10.1126/sciadv.abb0620

We report a microresonator platform that allows room temperature detection of electron spins in volumes on the order of 100 pl, and demonstrate its utility to study low levels of dopants in perovskite oxides. We exploit the toroidal moment in a planar anapole, using a single unit of an anapole metamaterial architecture to produce a microwave resonance exhibiting a spatially confined magnetic field hotspot and simultaneously high quality-factor (Q-factor). To demonstrate the broad implementability of this design and its scalability to higher frequencies, we deploy the microresonators in a commercial electron paramagnetic resonance (EPR) spectrometer operating at 10 GHz and a NIST-built EPR spectrometer operating at 35 GHz. We report continuous-wave (CW) EPR spectra for various samples, including a dilute Mn2+-doped perovskite oxide, CaTiO
3, and a transition metal complex, CuCl2 * 2H2O. The anapole microresonator presented here is expected to enable multifrequency EPR characterization of dopants and defects in perovskite oxide microcrystals and other volume-limited materials of technological importance.

Recent developments in MAS DNP-NMR of materials #DNPNMR

Rankin, Andrew G.M., Julien Trébosc, Frédérique Pourpoint, Jean-Paul Amoureux, and Olivier Lafon. “Recent Developments in MAS DNP-NMR of Materials.” Solid State Nuclear Magnetic Resonance 101 (September 2019): 116–43.

https://doi.org/10.1016/j.ssnmr.2019.05.009

Solid-state NMR spectroscopy is a powerful technique for the characterization of the atomic-level structure and dynamics of materials. Nevertheless, the use of this technique is often limited by its lack of sensitivity, which can prevent the observation of surfaces, defects or insensitive isotopes. Dynamic Nuclear Polarization (DNP) has been shown to improve by one to three orders of magnitude the sensitivity of NMR experiments on materials under Magic-Angle Spinning (MAS), at static magnetic field B0 ≥ 5 T, conditions allowing for the acquisition of high-resolution spectra. The field of DNP-NMR spectroscopy of materials has undergone a rapid development in the last ten years, spurred notably by the availability of commercial DNP-NMR systems. We provide here an in-depth overview of MAS DNP-NMR studies of materials at high B0 field. After a historical perspective of DNP of materials, we describe the DNP transfers under MAS, the transport of polarization by spin diffusion and the various contributions to the overall sensitivity of DNP-NMR experiments. We discuss the design of tailored polarizing agents and the sample preparation in the case of materials. We present the DNP-NMR hardware and the influence of key experimental parameters, such as microwave power, magnetic field, temperature and MAS frequency. We give an overview of the isotopes, which have been detected by this technique, and the NMR methods, which have been combined with DNP. Finally, we show how MAS DNP-NMR has been applied to gain new insights into the structure of organic, hybrid and inorganic materials with applications in fields, such as health, energy, catalysis, optoelectronics etc.

[NMR] Postdoctoral position at NYU (NMR, MRI, magnetometry, spin physics, battery research)

Postdoctoral position at New York University (NMR, MRI, magnetometry, spin physics, battery research) Department of Chemistry

Applications are solicited for an individual to be appointed as an
postdoctoral associate under the supervision of Alexej Jerschow. The research will include one or both of these research areas:

• In-situ and operando NMR/MRI and magnetometry of batteries and
electrochemical devices.
• Study of nuclear spin singlet state life times and singlet relaxation
mechanisms, the development of efficient singlet/triplet conversion pulse sequences and methodology, as well as para-hydrogen induced polarization (PHIP).

Successful applicants must hold a Ph.D. degree in a related field. The ideal candidate will have strong experience in two or more of these areas:

•       NMR or MRI
•       Spin dynamics simulations
•       Machine learning and image processing
•       Hardware/microcontroller/data acquisition set up / programming /operation
•       Magnetometry
•       Electrochemistry
•       Molecular dynamics or ab initio simulations

There is no requirement to master all areas, but depth in two or more areas will enable a good integration with several projects.

Some relevant publications:
•       PCCP 2020, 22, 9703-9712,
https://pubs.rsc.org/en/content/articlehtml/2020/cp/d0cp00935k.
•       Chem Mat 2020, 32, 5, 2107-2113
https://doi.org/10.1021/acs.chemmater.9b05246.
•       PNAS, 2020, https://doi.org/10.1073/pnas.1917172117.
•       JMR 319, 106811, 2020,
https://www.sciencedirect.com/science/article/pii/S1090780720301294.
•       Sci. Rep. 10, 1-7, 2020,
https://www.nature.com/articles/s41598-020-70505-0.
•       Nat Comm 9:1776, 2018, http://dx.doi.org/10.1038/s41467-018-04192-x
•       PNAS, 2016, 113, 10779-84,
http://www.pnas.org/content/early/2016/09/06/1607903113.abstract
•       CPC 2016, http://dx.doi.org/10.1002/cphc.201600663
•       JMR 2017, 284, 1-7 https://doi.org/10.1016/j.jmr.2017.09.005;
•       PCCP 17, 2015, 24370 – 24375, http://dx.doi.org/10.1039/c5cp03716f
•       PCCP, 2019, 21,2595-2600, https://doi.org/10.1039/C8CP06883F.
•       PNAS, 2019, 116, 18783-18789, https://doi.org/10.1073/pnas.1906976116.
•       JMR 2019, 309, 106601, https://doi.org/10.1016/j.jmr.2019.106601.

There is also an opportunity to be involved in other ongoing projects in the laboratory.

The lab is located in newly renovated facilities of the Molecular Nanoscience Center at NYU’s Washington Square Campus in the heart of Manhattan.

The terms of employment which would be a year, with a possibility of renewal, include a competitive salary and other benefits. Applications will be reviewed on a rolling basis, and candidates will be considered until the position is filled.

To be considered, all applicants must submit a cover letter summarizing research experience and specifying the interests in this position; a curriculum vitae (including a full list of publications); a statement of research interests; and two letters of reference.

Applications should be submitted to:

Alexej Jerschow
Professor of Chemistry
Chemistry Department
New York University
100 Washington Square East
New York, NY 10003
ph: +1 212 998 8451
fax: +1 212 995 4475
alexej.jerschow@nyu.edu
https://wp.nyu.edu/jerschow/

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Increased flow rate of hyperpolarized aqueous solution for dynamic nuclear polarization-enhanced magnetic resonance imaging achieved by an open Fabry–Pérot type microwave resonator #DNPNMR

Fedotov, Alexey, Ilya Kurakin, Sebastian Fischer, Thomas Vogl, Thomas F. Prisner, and Vasyl Denysenkov. “Increased Flow Rate of Hyperpolarized Aqueous Solution for Dynamic Nuclear Polarization-Enhanced Magnetic Resonance Imaging Achieved by an Open Fabry–Pérot Type Microwave Resonator.” Magnetic Resonance 1, no. 2 (November 18, 2020): 275–84.

https://doi.org/10.5194/mr-1-275-2020

A continuous flow dynamic nuclear polarization (DNP) employing the Overhauser effect at ambient temperatures can be used among other methods to increase sensitivity of magnetic resonance imaging (MRI). The hyperpolarized state of water protons can be achieved by flowing aqueous liquid through a microwave resonator placed directly in the bore of a 1.5 T MRI magnet. Here we describe a new open Fabry–Pérot resonator as DNP polarizer, which exhibits a larger microwave exposure volume for the flowing liquid in comparison with a cylindrical TE013 microwave cavity. The Fabry–Pérot resonator geometry was designed using quasi-optical theory and simulated by CST software. Performance of the new polarizer was tested by MRI DNP experiments on a TEMPOL aqueous solution using a blood-vessel phantom. The Fabry–Pérot resonator revealed a 2-fold larger DNP enhancement with a 4-fold increased flow rate compared to the cylindrical microwave resonator. This increased yield of hyperpolarized liquid allows MRI applications on larger target objects.

Tailored flavoproteins acting as light-driven spin machines pump nuclear hyperpolarization

Ding, Yonghong, Alexey S. Kiryutin, Ziyue Zhao, Qian-Zhao Xu, Kai-Hong Zhao, Patrick Kurle, Saskia Bannister, et al. “Tailored Flavoproteins Acting as Light-Driven Spin Machines Pump Nuclear Hyperpolarization.” Scientific Reports 10, no. 1 (December 2020): 18658.

https://doi.org/10.1038/s41598-020-75627-z

The solid-state photo-chemically induced dynamic nuclear polarization (photo-CIDNP) effect generates non-Boltzmann nuclear spin magnetization, referred to as hyperpolarization, allowing for high gain of sensitivity in nuclear magnetic resonance (NMR). Well known to occur in photosynthetic reaction centers, the effect was also observed in a light-oxygen-voltage (LOV) domain of the bluelight receptor phototropin, in which the functional cysteine was removed to prevent photo-chemical reactions with the cofactor, a flavin mononucleotide (FMN). Upon illumination, the FMN abstracts an electron from a tryptophan to form a transient spin-correlated radical pair (SCRP) generating the photo-CIDNP effect. Here, we report on designed molecular spin-machines producing nuclear hyperpolarization upon illumination: a LOV domain of aureochrome1a from Phaeodactylum tricornutum, and a LOV domain named 4511 from Methylobacterium radiotolerans (Mr4511) which lacks an otherwise conserved tryptophan in its wild-type form. Insertion of the tryptophan at canonical and novel positions in Mr4511 yields photo-CIDNP effects observed by 15N and 1H liquidstate high-resolution NMR with a characteristic magnetic-field dependence indicating an involvement of anisotropic magnetic interactions and a slow-motion regime in the transient paramagnetic state. The heuristic biomimetic design opens new categories of experiments to analyze and apply the photo-CIDNP effect.

[NMR] Post-doc available in SARS-CoV-2 biochemistry/solid-state NMR – Anja Böckmann, Lyon, France

Postdoctoral Position Available in Protein Solid-State NMR group – Anja Böckmann
MMSB, CNRS-Université Lyon 1, Lyon, France
A postdoctoral position is open at the MMSB in Lyon, France, for a common project with the group of Beat Meier at ETH Zurich, on structural studies of SARS-CoV-2 membrane proteins, including structural and accessory proteins. 
For more info see https://mmsb.cnrs.fr/equipe/rmn-du-solide-des-proteines/meeting/ or https://ssnmr.ethz.ch/the-group/open-positions0.html.
We are looking for an enthusiastic protein biochemist, possibly but not necessarily with a background in NMR, who will work hand in hand with the other post-doc on the project in Zurich. The focus in Lyon will be on the biochemical aspects of the project, including sample preparation and optimization by NMR, as well as studies on interactions/assemblies of the proteins, using cell-free protein synthesis. The work of the post-doc in Zurich will be complemtary, on state-of-the art fast MAS & high field solid-state NMR methods for the analysis of cell-free synthesized protein samples.
A fully equipped wet lab, as well as spectrometers ranging from 500 to 1000 MHz, are available, in particular a 800 WB magnet. 
We seek a candidate who would be ready to start beginning 2021.
For informal queries about the lab and research project, please contact Anja Böckmann by e-mail: a.bockmann@ibcp.fr
Interested candidates should register their application at https://emploi.cnrs.fr/Offres/CDD/UMR5086-ANJBOC-004/Default.aspx?lang=EN

 ———————————————————————–
Dr. Anja Böckmann
Protein Solid-State NMR
Molecular Microbiology and Structural Biochemistry
Institut de Biologie et Chimie des Protéines
UMR 5086 CNRS/Université de Lyon
7, passage du Vercors
69367 Lyon Cedex 07
France

Tel: +33472722649
a.bockmann@ibcp.frhttp://mmsb.cnrs.fr/en/team/protein-solid-state-nmr/http://mmsb.cnrs.fr/en/u/abockmann/

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