Monday, May 30, 2016

Multiscale computational modeling of (13)C DNP in liquids #DNPNMR


Kucuk, S.E. and D. Sezer, Multiscale computational modeling of (13)C DNP in liquids. Phys Chem Chem Phys, 2016. 18(14): p. 9353-7.


Dynamic nuclear polarization (DNP) enables the substantial enhancement of the NMR signal intensity in liquids. While proton DNP is dominated by the dipolar interaction between the electron and nuclear spins, the Fermi contact (scalar) interaction is equally important for heavier nuclei. The impossibility to predict the magnitude and field dependence of the scalar contribution hampers the application of high-field DNP to nuclei other than (1)H. We demonstrate that molecular dynamics (MD) simulations followed by density functional calculations of the Fermi contacts along the MD trajectory lead to quantitative agreement with the DNP coupling factors of the methyl and carbonyl carbons of acetone in water at 0.35 T. Thus, the accurate calculation of scalar-dominated DNP enhancement at a desired magnetic field is demonstrated for the first time. For liquid chloroform at fields above 9 T, our methodology predicts direct (13)C DNP enhancements that are two orders of magnitude larger than those of (1)H.

Sunday, May 29, 2016

[NMR] PhD position #DNPNMR

From the Ampere Magnetic Resonance List


A PhD studentship supported by the Marie Curie Actions-COFUND is available under the joint supervision of Dr. Armand MASION (CEREGE Laboratory www.cerege.fr) and Prof. Stéphane VIEL (Radical Chemistry Institute http://icr-amu.cnrs.fr) at Aix-Marseille University (located in the southern-east part of France).

The aim of this project is to develop dynamic nuclear polarization (DNP) NMR and MRI methodologies to study the speciation and mapping of Al-nanomaterials in an environmentally significant context. The environmental fate and potentially adverse effects of engineered aluminum nanoparticles, which are used in a wide range of industrial applications (e.g. pharmaceuticals, cosmetics, food, water treatment…), have received only marginal attention so far. The environmental reactivity, mobility and toxicity of nano-sized Al phases are controlled by their speciation, and especially their surface chemistry. The present project aims at determining the mechanisms controlling the fate of selected Al based nanomaterials in a wastewater treatment plant (WWTP) and the downstream natural environment. Given the affinity between Al and organics, the required analytical tools need to be able to determine the Al and C speciation with the least amount of sample preparation. Solid-state NMR is an element-specific probe that is extremely valuable to provide a detailed speciation for both Al and C nuclei, and is perfectly suited to analyze nanoparticles and their coatings. However, because it is conceptually necessary to monitor the Al nanophase in realistic environments (hence, at low concentrations), the so-called dynamic nuclear polarization (DNP) technique will have to be used to enhance the intrinsically low sensitivity of NMR. In addition, characterizing the fate and mobility of Al-nanomaterials also requires mapping their distribution within the different compartments of the system, including living organisms. In this context, magnetic resonance imaging (27Al MRI) could prove relevant because it is an element specific technique with a resolution in the µm3 range that makes it ideal for investigating the aggregation state of Al nanomaterials.

The successful candidate should have a strong background in physical-chemistry and chemistry with (possibly) a working knowledge in environmental science and/or geosciences. Experience in NMR spectroscopy is strongly desired. He/she needs to have excellent English communication skills (oral and written) and the ability to work as an active member of a multi-site, multi-disciplinary team. Basic knowledge in French is not required.


Contact: Armand MASION (masion@cerege.fr) or Stéphane VIEL (s.viel@univ-amu.fr)

The PhD funding provides:
• A net salary of 1625 €/month after taxes
• A 500 € travel allowance per year is provided to travel between Marseille and the student place of origin.
• Tailored training and personalized mentoring (Personal Career Development Plan and workshops)
• Financial support for international research training and conferences participations.
• A contribution to the research costs will be provided for the benefit of the student.
• Healthcare 

Deadline for application: June 24th 2016, midnight (French Time) 

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[NMR] Inaugural Workshop for Nottingham DNP MAS NMR Facility, UK #DNPNMR

From the Ampere Magnetic Resonance List



Dear Researcher,

This is a reminder that registration for the Inaugural Workshop for the Nottingham DNP MAS NMR Facility closes on 10th June, 2016.

The workshop will be held on Monday, 18th July, 2016 in the School of Physics and Astronomy, University of Nottingham. Attendance at the workshop will be free. However, for the sake of planning catering we ask attendees to register using a brief form on the Facility webpage at http://www.nottingham.ac.uk/dnpnmr


The final schedule of the Workshop is as follows:
9:30 - 10:30 - Coffee
10:00 - 10:30 - Welcome
10:30 - 11:15 - Robert G. Griffin
High Frequency DNP: New Applications and Time Domain Experiments
11:15 - 12:00 - Lyndon Emsley
Dynamic Nuclear Polarization Surface Enhanced NMR spectroscopy
12:00 - 14:00 Buffet Lunch and Facility Visit

14:00 - 14:45 - Daniel Lee
Methodology, Applications, and Instrumentation for MAS-DNP
14:45 - 15:30 - Frank Engelke
Dynamic Nuclear Polarization at Low Temperatures and Fast Sample Spinning
15:30 - 16:00 Coffee
16:00 - 16:45 - Marc Baldus
DNP on Intact Biomolecular Systems
16:45 - 17:30 - Clemens Glaubitz
DNP-enhanced Solid-state NMR for Mechanistic Studies of Receptors and Transport Proteins
17.30 - 18:00 - Facility Visit



We are looking forward to welcome you to Nottingham in July 2016

Subhradip Paul (Facility Manager)
Boyan Bonev (Life Sciences)
Jeremy Titman (Chemistry)
Walter Kockenberger (Physics and Astronomy)

Best regards,
Subhradip Paul

DNP MAS NMR Facility Manager
Sir Peter Mansfield MR Centre
School of Physics & Astronomy
University of Nottingham
Nottingham NG7 2RD
United Kingdom

P: +44 (0) 115-748-6278

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Friday, May 27, 2016

Magnetic resonance imaging of (1)H long lived states derived from parahydrogen induced polarization in a clinical system #DNPNMR


Graafen, D., et al., Magnetic resonance imaging of (1)H long lived states derived from parahydrogen induced polarization in a clinical system. J Magn Reson, 2016. 262: p. 68-72.


Hyperpolarization is a powerful tool to overcome the low sensitivity of nuclear magnetic resonance (NMR). However, applications are limited due to the short lifetime of this non equilibrium spin state caused by relaxation processes. This issue can be addressed by storing hyperpolarization in slowly decaying singlet spin states which was so far mostly demonstrated for non-proton spin pairs, e.g. (13)C-(13)C. Protons hyperpolarized by parahydrogen induced polarization (PHIP) in symmetrical molecules, are very well suited for this strategy because they naturally exhibit a long-lived singlet state. The conversion of the NMR silent singlet spin state to observable magnetization can be achieved by making use of singlet-triplet level anticrossings. In this study, a low-power radiofrequency pulse sequence is used for this purpose, which allows multiple successive singlet-triplet conversions. The generated magnetization is used to record proton images in a clinical magnetic resonance imaging (MRI) system, after 3min waiting time. Our results may open unprecedented opportunities to use the standard MRI nucleus (1)H for e.g. metabolic imaging in the future.

Wednesday, May 25, 2016

Dynamic Nuclear Polarization Enhanced MAS NMR Spectroscopy for Structural Analysis of HIV-1 Protein Assemblies #DNPNMR


Gupta, R., et al., Dynamic Nuclear Polarization Enhanced MAS NMR Spectroscopy for Structural Analysis of HIV-1 Protein Assemblies. J Phys Chem B, 2016. 120(2): p. 329-39.


Mature infectious HIV-1 virions contain conical capsids composed of CA protein, generated by the proteolytic cleavage cascade of the Gag polyprotein, termed maturation. The mechanism of capsid core formation through the maturation process remains poorly understood. We present DNP-enhanced MAS NMR studies of tubular assemblies of CA and Gag CA-SP1 maturation intermediate and report 20-64-fold sensitivity enhancements due to DNP at 14.1 T. These sensitivity enhancements enabled direct observation of spacer peptide 1 (SP1) resonances in CA-SP1 by dipolar-based correlation experiments, unequivocally indicating that the SP1 peptide is unstructured in assembled CA-SP1 at cryogenic temperatures, corroborating our earlier results. Furthermore, the dependence of DNP enhancements and spectral resolution on magnetic field strength (9.4-18.8 T) and temperature (109-180 K) was investigated. Our results suggest that DNP-based measurements could potentially provide residue-specific dynamics information by allowing for the extraction of the temperature dependence of the anisotropic tensorial or relaxation parameters. With DNP, we were able to detect multiple well-resolved isoleucine side-chain conformers; unique intermolecular correlations across two CA molecules; and functionally relevant conformationally disordered states such as the 14-residue SP1 peptide, none of which are visible at ambient temperatures. The detection of isolated conformers and intermolecular correlations can provide crucial constraints for structure determination of these assemblies. Overall, our results establish DNP-based MAS NMR spectroscopy as an excellent tool for the characterization of HIV-1 assemblies.

Tuesday, May 24, 2016

Essentials of Dynamic Nuclear Polarization #DNPNMR

Dear Colleague,

It is my pleasure to announce that a limited edition of 
    `Essentials of Dynamic Nuclear Polarization' 
is now available at the UK branch of Amazon: www.amazon.co.uk

This book is a concise introduction to dynamic nuclear polarization. 
It presents the foundations of the solid effect, Provotorov's theory,
thermal mixing and the cross effect, and includes some of the latest 
developments, such as the integrated solid effect.  It condenses half 
a century of personal experience in the field, and is oriented towards 
graduate students, researchers and anyone with a working knowledge 
of the quantum mechanics of spin.  

The summer school on `The principles of dynamic nuclear polarization' 
in Tramelan, Switzerland, from 22 to 26 August, will be based on this book
and participants will receive a complementary copy at the school.  
For further information please consult: 

Additional material will eventually be posted on my website: 

Yours sincerely,

Tom Wenckebach

Monday, May 23, 2016

Conceptual and instrumental progress in dissolution DNP #DNPNMR


Jahnig, F., G. Kwiatkowski, and M. Ernst, Conceptual and instrumental progress in dissolution DNP. J Magn Reson, 2016. 264: p. 22-9.


We discuss conceptual and instrumental progress in dissolution DNP since its introduction in 2003. In our view there are three critical steps in the dissolution DNP process: (i) The achievable polarization level in a sample. (ii) The time required to build up the polarization. (iii) The transfer of the sample to the measurement system with minimum loss of polarization. In this review we describe in detail these steps and the different methodological and instrumental implementations, which have been proposed to optimize them.

Friday, May 20, 2016

Nuclear hyperpolarization comes of age #DNPNMR


Jeschke, G. and L. Frydman, Nuclear hyperpolarization comes of age. J Magn Reson, 2016. 264: p. 1-2.


This is the introduction article to the recent Journal of Magnetic Resonance issue about DNP and hyperpoloarization.

Wednesday, May 18, 2016

Dynamic Nuclear Polarization enhanced NMR at 187GHz/284MHz using an Extended Interaction Klystron amplifier #DNPNMR


Kemp, T.F., et al., Dynamic Nuclear Polarization enhanced NMR at 187GHz/284MHz using an Extended Interaction Klystron amplifier. J Magn Reson, 2016. 265: p. 77-82.


A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer which uses a 187GHz (corresponding to (1)H NMR frequency of 284MHz) Extended Interaction Klystron (EIK) amplifier as the microwave source is briefly described. Its performance is demonstrated for a biomolecule (bacteriorhodopsin), a pharmaceutical, and surface functionalised silica. The EIK is very compact and easily incorporated into an existing spectrometer. The bandwidth of the amplifier is sufficient that it obviates the need for a sweepable magnetic field, once set, for all commonly used radicals. The variable power (CW or pulsed) output from the EIK is transmitted to the DNP-NMR probe using a quasi-optic system with a high power isolator and a corrugated waveguide which feeds the microwaves into the DNP-NMR probe. Curved mirrors inside the probe project the microwaves down the axis of the MAS rotor, giving a very efficient system such that maximum DNP enhancement is achieved with less than 3W output from the microwave source. The DNP-NMR probe operates with a sample temperature down to 90K whilst spinning at 8kHz. Significant enhancements, in excess of 100 for bacteriorhodopsin in purple membrane (bR in PM), are shown along with spectra which are enhanced by approximately 25 with respect to room temperature, for both the pharmaceutical furosemide and surface functionalised silica. These enhancements allow hitherto prohibitively time consuming experiments to be undertaken. The power at which the DNP enhancement in bR in PM saturates does not change significantly between 90K and 170K even though the enhancement drops by a factor of approximately 11. As the DNP build up time decreases by a factor 3 over this temperature range, the reduction in T1n is presumably a significant contribution to the drop in enhancement.

Monday, May 16, 2016

Ultra-low temperature MAS-DNP #DNPNMR


Lee, D., et al., Ultra-low temperature MAS-DNP. J. Magn. Reson., 2016. 264: p. 116-124.


Since the infancy of NMR spectroscopy, sensitivity and resolution have been the limiting factors of the technique. Regular essential developments on this front have led to the widely applicable, versatile, and powerful spectroscopy that we know today. However, the Holy Grail of ultimate sensitivity and resolution is not yet reached, and technical improvements are still ongoing. Hence, high-field dynamic nuclear polarization (DNP) making use of high-frequency, high-power microwave irradiation of electron spins has become very promising in combination with magic angle sample spinning (MAS) solid-state NMR experiments. This is because it leads to a transfer of the much larger polarization of these electron spins under suitable irradiation to surrounding nuclei, greatly increasing NMR sensitivity. Currently, this boom in MAS-DNP is mainly performed at minimum sample temperatures of about 100 K, using cold nitrogen gas to pneumatically spin and cool the sample. This Perspective deals with the desire to improve further the sensitivity and resolution by providing “ultra”-low temperatures for MAS-DNP, using cryogenic helium gas. Different designs on how this technological challenge has been overcome are described. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a large cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas brings the additional advantage of sample spinning frequencies that can greatly surpass those achievable with nitrogen gas, due to the differing fluidic properties of these two gases. It is shown that using ultra-low temperatures for MAS-DNP results in substantial experimental sensitivity enhancements and according time-savings. Access to this temperature range is demonstrated to be both viable and highly pertinent.

Thursday, May 12, 2016

Symmetry constraints on spin dynamics: Application to hyperpolarized NMR


Levitt, M.H., Symmetry constraints on spin dynamics: Application to hyperpolarized NMR. J Magn Reson, 2016. 262: p. 91-9.


Spin dynamical evolution is constrained by the symmetries of the spin Hamiltonians that generate the quantum dynamics. The consequences of symmetry-induced constraints are examined for some common hyperpolarized NMR experiments, including the excitation of singlet order in spin-pair systems, and the transfer of parahydrogen-induced hyperpolarized singlet order to magnetization in systems displaying chemical and magnetic equivalence.

Wednesday, May 11, 2016

Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures


Matsuki, Y., et al., Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures. J Magn Reson, 2016. 264: p. 107-15.


Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0<9T) and temperatures (T>90K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395GHz-600MHz and 460GHz-700MHz DNP NMR spectrometers. The latter 700MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T approximately 100K and approximately 30K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented.

Tuesday, May 10, 2016

[NMR] AMPERE biological solid-state NMR school in Palma de Mallorca October 2016 #DNPNMR #NMR

From the Ampere Magnetic Resonance List



Dear NMR students and post-docs, dear supervisors, 

it is a pleasure for us to announce the 6th biological solid-state NMR school which will be held at the Universitat de les Illes Balears in Palma de Mallorca from October 9-14 this year. The school will be organized as an event of the Groupement AMPERE, the european magnetic resonance society, and with support from the European Biophysical Society (EBSA). 

Topics covered include solid-state NMR thery and Hamiltonians, recoupling techniques, DNP & EPR, relaxation, sample preparation, sequential assignments and structure determination. Ample time will be dedicated to practicals. Lectures on x-ray crystallography and electron microscopy will integrate other structural techniques as important perspectives. 

Registration is available through http://ampereschool2016.org/.
There is a limited amount of student grants available (please apply before July 1st). 

Please note that registration will close September 1st, or when the attendance maximums at the course site are reached.
We are looking forward very much to seeing you in Palma this autumn, 


The organizing committee


The lectures will be given by the following speakers:
Marc Baldus (Utrecht)
Anja Böckmann, (Lyon)
Enrica Bordignon (Berlin)
Andrea Dessen (Grenoble)
Frank Engelke (Karlsruhe)
Matthias Ernst (ETH Zurich)
Bob Griffin (Boston)
Huub de Groot (Leiden)
Malene Jensen (Grenoble)
P. K. Madhu (Mumbai)
Beat H. Meier (ETH Zurich)
Hartmut Oschkinat (FMP Berlin)
Stefan Raunser (Dortmund)
Bernd Reif (TU München)
Thomas Vosegaard (Aarhus) 


Organizing committee:
Anja Böckmann
Matthias Ernst
Beat Meier
Hartmut Oschkinat

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Monday, May 9, 2016

[NMR] Preclinical MRI Staff Scientist Position at The Weizmann Institute

From the Ampere Magnetic Resonance List



The Weizmann Institute of Science, Israel, seeks candidates for the position of a tenure-track staff scientist in Magnetic Resonance Imaging. The scientist will be in charge of the Institute's central core MRI/MRS preclinical facilities which include a state-of-the-art 15.2 T preclinical animal imaging magnet, one of the first of its kind worldwide, as well as a 400 MHz wide-bore and 4.7 T magnets. 

About The Work
The work spans a wide range of skills, including: (1.) Working closely with experimental groups at the Institute; setting up and carrying out animal imaging protocols. (2.) Collaborating with Institute scientists in developing new pulse sequences and analysis methodologies for studying in-vivo metabolism, anatomy and physiology. (3.) Overseeing the imaging facilities and ensuring their integrity and viability. 

Candidates should ideally have both a strong quantitative background in magnetic resonance, as well as experience in MRI and animal imaging. However, motivated and outstanding people are encouraged to apply even if they lack some of the necessary prerequisites. 

To Apply
To apply, please email your CV to Dr. Assaf Tal, assaf.tal@weizmann.ac.il.

About The Institute.
The Weizmann Institute provides an outstanding intellectual environment within a beautiful campus. It is internationally renown and has played a major role in magnetic resonance. It currently houses multiple labs studying diverse phenomena ranging from electron paramagnetism of proteins to solid state NMR, hyperpolarization techniqeus, in-vivo spectroscopy and imaging in animal models and in humans. Weizmann has recently made unprecedented investments in magnetic resonance, including hiring of multiple new faculty members, and purchasing a 1 GHz NMR liquid state spectrometer, 15.2 T preclinical MRI and 7 T human MRI, among others.

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Optimizing water hyperpolarization and dissolution for sensitivity-enhanced 2D biomolecular NMR


Olsen, G., et al., Optimizing water hyperpolarization and dissolution for sensitivity-enhanced 2D biomolecular NMR. J Magn Reson, 2016. 264: p. 49-58.


A recent study explored the use of hyperpolarized water, to enhance the sensitivity of nuclei in biomolecules thanks to rapid proton exchanges with labile amide backbone and sidechain groups. Further optimizations of this approach have now allowed us to achieve proton polarizations approaching 25% in the water transferred into the NMR spectrometer, effective water T1 times approaching 40s, and a reduction in the dilution demanded for the cryogenic dissolution process. Further hardware developments have allowed us to perform these experiments, repeatedly and reliably, in 5mm NMR tubes. All these ingredients - particularly the 3000x (1)H polarization enhancements over 11.7T thermal counterparts, long T1 times and a compatibility with high-resolution biomolecular NMR setups - augur well for hyperpolarized 2D NMR studies of peptides, unfolded proteins and intrinsically disordered systems undergoing fast exchanges of their protons with the solvent. This hypothesis is here explored by detailing the provisions that lead to these significant improvements over previous reports, and demonstrating 1D coherence transfer experiments and 2D biomolecular HMQC acquisitions delivering NMR spectral enhancements of 100-500x over their optimized, thermally-polarized, counterparts.

Friday, May 6, 2016

Magnetic resonance imaging of DNP enhancements in a rotor spinning at the magic angle


Perras, F.A., T. Kobayashi, and M. Pruski, Magnetic resonance imaging of DNP enhancements in a rotor spinning at the magic angle. J Magn Reson, 2016. 264: p. 125-30.


Simulations performed on model, static, samples have shown that the microwave power is non-uniformly distributed in the magic angle spinning (MAS) rotor when using conventional dynamic nuclear polarization (DNP) instrumentation. Here, we applied the stray-field magic angle spinning imaging (STRAFI-MAS) experiment to generate a spatial map of the DNP enhancements in a full rotor, which is spun at a low rate in a commercial DNP-MAS NMR system. Notably, we observed that the enhancement factors produced in the center of the rotor can be twice as large as those produced at the top of the rotor. Surprisingly, we observed that the largest enhancement factors are observed along the axis of the rotor as opposed to against its walls, which are most directly irradiated by the microwave beam. We lastly observed that the distribution of enhancement factors can be moderately improved by degassing the sample and increasing the microwave power. The inclusion of dielectric particles greatly amplifies the enhancement factors throughout the rotor. The STRAFI-MAS approach can provide useful guidance for optimizing the access of microwave power to the sample, and thereby lead to further increases in sensitivity of DNP-MAS NMR.

Wednesday, May 4, 2016

Liquid state DNP at high magnetic fields: Instrumentation, experimental results and atomistic modelling by molecular dynamics simulations


Prisner, T., V. Denysenkov, and D. Sezer, Liquid state DNP at high magnetic fields: Instrumentation, experimental results and atomistic modelling by molecular dynamics simulations. J Magn Reson, 2016. 264: p. 68-77.


Dynamic nuclear polarization (DNP) at high magnetic fields has recently become one of the major research areas in magnetic resonance spectroscopy and imaging. Whereas much work has been devoted to experiments where the polarization transfer from the electron spin to the nuclear spin is performed in the solid state, only a few examples exist of experiments where the polarization transfer is performed in the liquid state. Here we describe such experiments at a magnetic field of 9.2 T, corresponding to a nuclear Larmor frequency of 400MHz for proton spins and an excitation frequency of 263GHz for the electron spins. The technical requirements to perform such experiments are discussed in the context of the double resonance structures that we have implemented. The experimental steps that allowed access to the enhancement factors for proton spins of several organic solvents with nitroxide radicals as polarizing agents are described. A computational scheme for calculating the coupling factors from molecular dynamics (MD) simulations is outlined and used to highlight the limitations of the classical models based on translational and rotational motion that are typically employed to quantify the observed coupling factors. The ability of MD simulations to predict enhancements for a variety of radicals and solvent molecules at any magnetic field strength should prove useful in optimizing experimental conditions for DNP in the liquid state.

Monday, May 2, 2016

Basic facts and perspectives of Overhauser DNP NMR


Ravera, E., C. Luchinat, and G. Parigi, Basic facts and perspectives of Overhauser DNP NMR. J Magn Reson, 2016. 264: p. 78-87.


After the first surprisingly large (1)H DNP enhancements of the water signal in aqueous solutions of nitroxide radicals observed at high magnetic fields, Overhauser DNP is gaining increasing attention for a number of applications now flourishing, showing the potentialities of this mechanism in solution and solid state NMR as well as in MRI. Unexpected Overhauser DNP enhancements in insulating solids were recently measured at 100K, with a magnitude which increases with the applied magnetic field. We recapitulate here the theoretical premises of Overhauser DNP in solution and analyze the effects of the various parameters on the efficacy of the mechanism, underlining the link between the DNP enhancements and the field dependent relaxation properties. Promisingly, more effective DNP enhancements are expected by exploiting the potentialities offered by (13)C detection and the use of supercritical fluids.

Sunday, May 1, 2016

[NMR] PhD fellowship #DNPNMR

From the Ampere Magnetic Resonance List



Laboratory: Aix Marseille University/CNRS, Institut de Chimie Radicalaire (UMR 7273)

Thesis supervisor: Pr. Stéphane VIEL

Co-supervisor: Dr. Giulia MOLLICA

Title: Development of new methods for the preparation of solid samples for the NMR analysis of synthetic polymers using dynamic nuclear polarisation.

Description: The knowledge of the structure-property relationships in polymer materials is fundamental to understand and predict their macroscopic applications and aging behavior. In this context, NMR appears as a viable option because it is a non-destructive technique that can study polymer materials in the solid-state with atomic resolution, and access their supramolecular structure over a large range of molecular weights without the need of translational order. However, this information is often hindered by the low sensitivity of NMR. Recently, we have shown how such inherent limitation could be strongly alleviated with the help of Dynamic Nuclear Polarization (DNP), which enhances solid-state NMR sensitivity by transferring the electron spin polarisation of exogenous paramagnetic sources to nuclei via microwave irradiation of the sample at cryogenic temperature. Notably, our work has shown the strong potential of DNP for the structural elucidation of functional polymers, but has also revealed that the sample preparation methods currently available for DNP are far from being optimal in the case of polymeric materials. The aim of this work is to develop new efficient methods for DNP sample preparation by exploiting technologies borrowed from process engineering for the analysis of functional polymeric materials by DNP NMR.

References

1. Ouari, O.; Phan, T.; Ziarelli, F.; Casano, G.; Aussenac, F.; Thureau, P.; Gigmes, D.; Tordo, P.; Viel, S., ACS Macro Lett. 2013, 2, 715.

2. Ziarelli, F.; Casciola, M.; Donnadio, A.; Pica, M.; Sauvée, C.; Aussenac, F.; Capitani, D.; Viel, S., Chem. Commun. 2014, 50, 10137.

3. Le, D.; Casano, G.; Phan, T. N. T.; Ziarelli, F.; Ouari, O.; Aussenac, F.; Thureau, P.; Mollica, G.; Gigmes, D.; Tordo, P.; Viel, S., Macromolecules 2014, 47, 3909.

4. Le, D.; Ziarelli, F.; Phan, T. N. T.; Mollica, G.; Thureau, P.; Aussenac, F.; Ouari, O.; Gigmes, D.; Tordo, P.; Viel, S., Macromol. Rapid Comm. 2015, 36, 1416.

5. Mollica, G.; Le, D.; Ziarelli, F.; Casano, G.; Ouari, O.; Phan, T. N. T.; Aussenac, F.; Thureau, P.; Gigmes, D.; Tordo, P.; Viel, S., ACS Macro Lett. 2014, 3, 922.

6. Mollica, G.; Dekhil, M.; Ziarelli, F.; Thureau, P.; Viel, S., Angew. Chem. Int. Ed. 2015, 54, 6028.

7. Besson, E.; Ziarelli, F.; Bloch, E.; Gerbaud, G.; Queyroy, S.; Viel, S.; Gastaldi, S., Chem. Commun. 2016, 52, 5531.

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Procedure: All the necessary information is reported here: http://www.edsc250.univ-cezanne.fr/recrutement/modalites.html

Applicants should provide:

- a cover/motivation letter
- a CV
- personal details (by filling the form available through the web link provided above)
- a reference letter from the master supervisor (in a sealed envelop)
- the master grades obtained (M1 and M2 levels)

All information must be sent to Stéphane VIEL (s.viel@univ-amu.fr)

In case your application is successful, you will be required to attend an oral examination by the Doctoral School of Chemistry (ED250) which will take place May 31, 2016. The final ranking will determine the appointment for a doctoral research fellowship of 3 years.

For all complementary information, please contact: Stéphane VIEL (s.viel@univ-amu.fr or +33 4 91 28 89 02).

Sincerely

Stéphane VIEL



Cordialement,


Stéphane Viel - Professeur des Universités - ICR Institut de Chimie Radicalaire (UMR CNRS 7273)
Aix-Marseille Université - Service 512 - ST JEROME - Avenue Escadrille Normandie Niemen - 13013 Marseille
Tél: +33(0)4 91 28 89 02 - Mobile : +33(0)6 68 27 29 01
Afin de respecter l'environnement, merci de n'imprimer cet email que si nécessaire.

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