Thursday, March 31, 2016

EUROMAR 2016, July 3-7 in Aarhus, Denmark

From the Ampere Magnetic Resonance List

Dear colleagues

The EUROMAR 2016 Ampere conference takes place in Aarhus, Denmark July 3rd-7th 2016. Registration and abstract submission is available through the web-site: Early bird registration and abstract deadline is April 15, 2016. Note that the conference offers a significantly student discounts and that cheap housing is available along with high quality hotel rooms – booking of accommodation is possible together with the registration. 

The conference will cover a broad list of topics within magnetic resonance, and participation of a long list of distinguished speakers presenting their latest research is confirmed. For details, please visit

Please note that Aarhus is #13 in New York Times list of places to go in 2016 ( and has been highlighted as top-5 exciting place to visit by Vogue ( Finally it is worht noting that midsummer where the sun sets after 10 pm is the best time of year to visit Denmark.

We look forward to welcoming you in Aarhus this summer for an outstanding conference. You may read more about the conference on the web site above and meet us at Facebook:

On behalf of the organisers,
Frans Mulder & Thomas Vosegaard

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Wednesday, March 30, 2016

DNP 2016 Summer School organized by the EPFL #DNPNMR

Dear DNP Community

On behalf of the Organizing Committee it’s our pleasure to invite you to attend the next DNP School 2016, which will be held from August 22tnh to August 26th in Tramelan, a little Swiss village at 900 m elevation in the Bernese Jura close to Biel, Switzerland.

The School is addressed to PhD students and young researchers and focuses on theoretical and experimental aspects of dynamic nuclear polarization in the solid state. It is organized jointly by the EPFL (Lausanne) and the Paul Scherrer Institute (Villigen). It follows earlier schools in 2008 and 2012 held at PSI and will show new aspects. 

The principles of dynamic nuclear polarization
A PhD-level summer school

Main lecturer
Prof. W. Th. Wenckebach

Invited lecturers
Prof. J. H. Ardenkjaer-Larsen, Technical University of Denmark
Prof. S. Vega, Weizmann Institute of Science
Prof. Matthew E. Merritt, The University of Texas Southwestern

It is reachable by public transport from Zürich Airport, Basel Euro Airport and Lausanne in about 2 hours.

The number of places is limited. Further information and a preregistration form is now available through the website: 

We would appreciate it if you could kindly disseminate this information to others interested in the School.

With best regards,
The organizing committee
Patrick Hautle (PSI)
Ben van den Brandt (PSI)
Arnaud Comment (EPFL)


The principles of dynamic nuclear polarization
By prof W.Th. Wenckebach
A PhD-level summer school in Tramelan, Switzerland, 22-26 August 2016
Jointly organized by EPFL (Lausanne) and Paul Scherrer Institute (Villigen)

Photochemically Induced Dynamic Nuclear Polarization Observed by Solid-State NMR in a Uniformly (13)C-Isotope-Labeled Photosynthetic Reaction Center

Paul, S., et al., Photochemically Induced Dynamic Nuclear Polarization Observed by Solid-State NMR in a Uniformly (13)C-Isotope-Labeled Photosynthetic Reaction Center. J Phys Chem B, 2015. 119(43): p. 13897-903.

A sample of solubilized and quinone-depleted reaction centers from the purple bacterium Rhodobacter (R.) sphaeroides wild type has been prepared entirely (13)C and (15)N isotope labeled at all positions of the protein as well as of the cofactors. In this sample, the occurrence of the solid-state photo-CIDNP (photochemically induced dynamic nuclear polarization) effect has been probed by (13)C solid-state magic-angle spinning NMR under illumination. Under continuous illumination, signal intensities are modified by the three-spin mixing (TSM) mechanism. Time-resolved illumination experiments reveal the occurrence of light-induced nuclear polarization on the time scale of hundreds of microseconds, initially dominated by the transient polarization of the singlet branch of the radical-pair mechanism. A first kinetic analysis shows that the lifetime of the polarization from the singlet branch, indicated by the enhanced absorptive intensities of the signals from aliphatic carbons, is significantly extended. Upon arrival of the polarization from the triplet decay branch, emissive polarization caused by the TSM mechanism is observed. Also, this arrival is significantly delayed. The decay of TSM polarization occurs in two steps, assigned to intra- and intermolecular spin diffusion.

Monday, March 28, 2016

A New Tool for NMR Crystallography: Complete (13)C/(15)N Assignment of Organic Molecules at Natural Isotopic Abundance Using DNP-Enhanced Solid-State NMR

Marker, K., et al., A New Tool for NMR Crystallography: Complete (13)C/(15)N Assignment of Organic Molecules at Natural Isotopic Abundance Using DNP-Enhanced Solid-State NMR. J Am Chem Soc, 2015. 137(43): p. 13796-9.

NMR crystallography of organic molecules at natural isotopic abundance (NA) strongly relies on the comparison of assigned experimental and computed NMR chemical shifts. However, a broad applicability of this approach is often hampered by the still limited (1)H resolution and/or difficulties in assigning (13)C and (15)N resonances without the use of structure-based chemical shift calculations. As shown here, such difficulties can be overcome by (13)C-(13)C and for the first time (15)N-(13)C correlation experiments, recorded with the help of dynamic nuclear polarization. We present the complete de novo (13)C and (15)N resonance assignment at NA of a self-assembled 2'-deoxyguanosine derivative presenting two different molecules in the asymmetric crystallographic unit cell. This de novo assignment method is exclusively based on aforementioned correlation spectra and is an important addition to the NMR crystallography approach, rendering firstly (1)H assignment straightforward, and being secondly a prerequisite for distance measurements with solid-state NMR.

Friday, March 25, 2016

Long-lived spin states as a source of contrast in magnetic resonance spectroscopy and imaging

Kiryutin, A.S., et al., Long-lived spin states as a source of contrast in magnetic resonance spectroscopy and imaging. J Magn Reson, 2015. 261: p. 64-72.

A method is proposed to create Long-Lived spin States (LLSs) from longitudinal spin magnetization, which is based on adiabatic switching of a Radio-Frequency (RF) field with proper frequency. The technique is simple to implement with standard Nuclear Magnetic Resonance (NMR) equipment, providing an excellent conversion of population from the triplet T+ (or T-) state to the singlet state of a pair of spins and back. The method has been tested for the amino acid tyrosine and its partially deuterated isotopomer; for the deuterated compound, we have achieved a LLS lifetime, which exceeds the longitudinal relaxation time by a factor of 21. Furthermore, by slightly modifying the method, an enhanced contrast with respect to LLSs in NMR spectra is achieved; contrast enhancements of more than 1200 are feasible. This enables efficient suppression of longitudinal spin magnetization in NMR allowing one to look selectively at LLSs. Using this method we have demonstrated that not only spectral but also spatial contrast can be achieved: we have obtained spatial NMR images with strongly improved contrast originating from the difference of LLS lifetimes at different positions in the sample.

Wednesday, March 23, 2016

Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization

Hoff, D.E., et al., Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization. Solid State Nucl Magn Reson, 2015. 72: p. 79-89.

Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198GHz MAS DNP probe. Our calculations show that a microwave power input of 17W is required to generate an average EPR nutation frequency of 0.84MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions.

Monday, March 21, 2016

Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz

Yoon, D., et al., Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz. J Magn Reson, 2016. 262: p. 62-7.

An increase in Dynamic Nuclear Polarization (DNP) signal intensity is obtained with a tunable gyrotron producing frequency modulation around 260GHz at power levels less than 1W. The sweep rate of frequency modulation can reach 14kHz, and its amplitude is fixed at 50MHz. In water/glycerol glassy ice doped with 40mM TEMPOL, the relative increase in the DNP enhancement was obtained as a function of frequency-sweep rate for several temperatures. A 68 % increase was obtained at 15K, thus giving a DNP enhancement of about 80. By employing lambda/4 and lambda/8 polarizer mirrors, we transformed the polarization of the microwave beam from linear to circular, and achieved an increase in the enhancement by a factor of about 66% for a given power.

Friday, March 18, 2016

Transport and imaging of brute-force (13)C hyperpolarization

Hirsch, M.L., et al., Transport and imaging of brute-force (13)C hyperpolarization. J Magn Reson, 2015. 261: p. 87-94.

We demonstrate transport of hyperpolarized frozen 1-(13)C pyruvic acid from its site of production to a nearby facility, where a time series of (13)C images was acquired from the aqueous dissolution product. Transportability is tied to the hyperpolarization (HP) method we employ, which omits radical electron species used in other approaches that would otherwise relax away the HP before reaching the imaging center. In particular, we attained (13)C HP by 'brute-force', i.e., using only low temperature and high-field (e.g., T< approximately 2K and B approximately 14T) to pre-polarize protons to a large Boltzmann value ( approximately 0.4% (1)H polarization). After polarizing the neat, frozen sample, ejection quickly (<1s) passed it through a low field (B<100G) to establish the (1)H pre-polarization spin temperature on (13)C via the process known as low-field thermal mixing (yielding approximately 0.1% (13)C polarization). By avoiding polarization agents (a.k.a. relaxation agents) that are needed to hyperpolarize by the competing method of dissolution dynamic nuclear polarization (d-DNP), the (13)C relaxation time was sufficient to transport the sample for approximately 10min before finally dissolving in warm water and obtaining a (13)C image of the hyperpolarized, dilute, aqueous product ( approximately 0.01% (13)C polarization, a >100-fold gain over thermal signals in the 1T scanner). An annealing step, prior to polarizing the sample, was also key for increasing T1 approximately 30-fold during transport. In that time, HP was maintained using only modest cryogenics and field (T approximately 60K and B=1.3T), for T1((13)C) near 5min. Much greater time and distance (with much smaller losses) may be covered using more-complete annealing and only slight improvements on transport conditions (e.g., yielding T1 approximately 5h at 30K, 2T), whereas even intercity transfer is possible (T1>20h) at reasonable conditions of 6K and 2T. Finally, it is possible to increase the overall enhancement near d-DNP levels (i.e., 10(2)-fold more) by polarizing below 100mK, where nanoparticle agents are known to hasten T1 buildup by 100-fold, and to yield very little impact on T1 losses at temperatures relevant to transport.


From the Ampere Magnetic Resonance List

Technische Universität München, Munich, Germany


We are looking for a postdoc who will join our project within the Collaborative Research Centre 824 Imaging for Selection, Monitoring and Individualization of Cancer Therapies ( at the Department of Nuclear Medicine at the Technische Universität München (Germany). The initial employment has a duration of 1 year (extension is possible) starting as soon as possible. The salary is according to TV-L E13.

The Department of Nuclear Medicine at Technische Universität München, Germany, is internationally highly regarded in the field of molecular imaging. Since many years, multimodal imaging (SPECT, PET, MRI, CT) in clinical and preclinical applications is a core focus of our department. Recently a 7 T MRI system for preclinical applications has been installed together with a HyperSense DNP Polarizer for hyperpolarized 13C MR imaging.

We are looking for a postdoc with strong background in preclinical imaging and broad experience in metabolic imaging in animal models to join this preclinical 7T MRI laboratory including the DNP Polarizer. The person is expected to take on the role of the biomedical imaging expert, bringing in strong expertise on MR imaging in preclinical models.

The person will further be responsible for research design, internal and external collaborations for preclinical imaging, and study-execution, working closely together with the team of PhD students and the 7T responsible physicist. In addition, the candidate is expected to develop his/her own research focus within the framework of the department's scientific goals.

Candidates should have a PhD degree in Physics, (Bio-)Chemistry, Biology, or a related field. Proven experience in the field of clinical or preclinical MRI is required. We expect scientific achievements, very good communication skills, and the ability to work in an interdisciplinary team. Women are especially encouraged to apply. Handicapped applicants with equal qualifications will be given preferential treatment.

Applications should include a cover letter, a CV and a list of own publications together with the names of three references and should be sent to:

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Wednesday, March 16, 2016

Strategy for Enhancement of (13)C-Photo-CIDNP NMR Spectra by Exploiting Fractional (13)C-Labeling of Tryptophan

Eisenreich, W., et al., Strategy for Enhancement of (13)C-Photo-CIDNP NMR Spectra by Exploiting Fractional (13)C-Labeling of Tryptophan. J Phys Chem B, 2015. 119(43): p. 13934-43.

The photo-CIDNP effect has proven to be useful to strongly enhance NMR signals of photochemically active proteins simply by irradiation with light. The evolving characteristic patterns of enhanced absorptive and emissive NMR lines can be exploited to elucidate the photochemistry and photophysics of light-driven protein reactions. In particular, by the assignment of (13)C NMR resonances, redox-active amino acids may be identified and thereby electron-transfer pathways unraveled, in favorable cases, even with (13)C at natural abundance. If signal enhancement is weak, uniform (13)C isotope labeling is traditionally applied to increase the signal strength of protein (13)C NMR. However, this typically leads to cross relaxation, which transfers light-induced nuclear-spin polarization to adjacent (13)C nuclei, thereby preventing an unambiguous analysis of the photo-CIDNP effect. In this contribution, two isotope labeling strategies are presented; one leads to specific but ubiquitous (13)C labeling in tryptophan, and the other is based on fractional isotope labeling affording sets of isotopologs with low probability of next-neighbor isotope accumulation within individual tryptophan molecules. Consequently, cross relaxation is largely avoided while the signal enhancement by (13)C enrichment is preserved. This results in significantly simplified polarization patterns that are easier to analyze with respect to the generation of light-generated nuclear-spin polarization.

Monday, March 14, 2016

Surface ligand-directed pair-wise hydrogenation for heterogeneous phase hyperpolarization

Gloggler, S., et al., Surface ligand-directed pair-wise hydrogenation for heterogeneous phase hyperpolarization. Chem Commun (Camb), 2016. 52(3): p. 605-8.

para-Hydrogen induced polarization is a technique of magnetic resonance hyperpolarization utilizing hydrogen's para-spin state for generating signal intensities at magnitudes far greater than state-of-the-art magnets. Platinum nanoparticle-catalysts with cysteine-capping are presented. The measured polarization is the highest reported to date in water, paving pathways for generating medical imaging contrast agents.

Friday, March 11, 2016

Low field photo-CIDNP in the intramolecular electron transfer of naproxen-pyrrolidine dyads

Magin, I.M., et al., Low field photo-CIDNP in the intramolecular electron transfer of naproxen-pyrrolidine dyads. Phys Chem Chem Phys, 2016. 18(2): p. 901-7.

Photoinduced processes with partial (exciplex) and full charge transfer in donor-acceptor systems are of interest because they are frequently used for modeling drug-protein binding. Low field photo-CIDNP (chemically induced dynamic nuclear polarization) for these processes in dyads, including the drug, (S)- and (R)-naproxen and (S)-N-methyl pyrrolidine in solutions with strong and weak permittivity have been measured. The dramatic influence of solvent permittivity on the field dependence of the N-methyl pyrrolidine (1)H CIDNP effects has been found. The field dependences of both (R,S)- and (S,S)-dyads in a polar medium are the curves with a single extremum in the area of the S-T+ terms intersection. Moreover, the CIDNP field dependences of the same protons measured in a low polar medium present curves with several extrema. The shapes of the experimental CIDNP field dependence with two extrema have been described using the Green function approach for the calculation of the CIDNP effects in the system without electron exchange interactions. The article discusses the possible causes of the differences between the CIDNP field dependence detected in a low-permittivity solvent with the strong Coulomb interactions and in a polar solvent.

Wednesday, March 9, 2016

Effects of biradical deuteration on the performance of DNP: towards better performing polarizing agents

Perras, F.A., et al., Effects of biradical deuteration on the performance of DNP: towards better performing polarizing agents. Phys Chem Chem Phys, 2016. 18(1): p. 65-9.

We study the effects of the deuteration of biradical polarizing agents on the efficiency of dynamic nuclear polarization (DNP) via the cross-effect. To this end, we synthesized a series of bTbK and TOTAPol biradicals with systematically increased deuterium substitution. The deuteration increases the radicals' relaxation time, thus contributing to a higher saturation factor and larger DNP enhancement, and reduces the pool of protons within the so-called spin diffusion barrier. Notably, we report that full or partial deuteration leads to improved DNP enhancement factors in standard samples, but also slows down the build-up of hyperpolarization. Improvements in DNP enhancements factors of up to 70% and time savings of up to 38% are obtained upon full deuteration. It is foreseen that this approach may be applied to other DNP polarizing agents thus enabling further sensitivity improvements.

[NMR] Postdoc positions in Hyperpolarized 13C MR

Fromt the Ampere Magnetic Resonance List

The University of Maryland School of Medicine has expanded its molecular imaging and interventional research capabilities by establishing the Center for Metabolic Imaging and Therapeutics. The center houses a GE SpinLabTM dynamic nuclear polarizer suitable for preclinical and clinical applications, adjacent to both a new GE 3T 750w MR scanner and an MR Solutions MRS 3017 Preclinical Benchtop MR scanner. The GE MR scanner is also integrated with an Insightec 1024-element high-intensity focused ultrasound (HIFU) system for image-guided interventions (a small-animal 8-element HIFU system by Image Guided Therapy is also available that can be used as a stand-alone unit or interfaced with a Bruker 7T small animal scanner). This expansion is aimed to facilitate both basic science and clinical research by exploring novel molecular imaging agent-based technologies for screening, early disease detection and treatment response, and real-time image-guided interventions.

Multiple postdoctoral research fellowship positions are available in the metabolic imaging group led by Dr. Dirk Mayer. Specific areas of research include optimized acquisition and reconstruction techniques, kinetic modeling for quantitative analysis, and new probe development. These methods will be applied to animal models (e.g., traumatic brain injury, cancer, liver disease) with the eventual goal to translate them to patients. This is an exciting opportunity to work at one of the first sites that will do translational/clinical hyperpolarized 13C MRI/MRS.

The candidate should have a Ph.D. (or equivalent degree) in engineering, physics, physical chemistry, or similar fields. The ideal candidate has a strong background in NMR physics with particular emphasis on in vivo imaging and/or spectroscopy, data acquisition and signal/image processing/analysis. Experience in pulse sequence programming (ideally on GE and/or MR Solutions scanners) is preferred. Knowledge of other computer languages, including C++, Matlab and IDL, and experience in performing small animal imaging is also desirable. Qualified applicants should also have a track record of first-author research papers published in peer-reviewed journals.

Interested individuals should send a letter detailing their research interests, an updated CV and contact information for at least two references Dirk Mayer, Ph.D. (

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Monday, March 7, 2016

Interview with Robert Tycko: On amyloids, Alzheimer disease, and solid-state NMR

Besides his contributions to solid-state NMR spectroscopy and it's application to study bio-macromolecular systems, Rob Tycko is also very active in DNP research.

Skrynnikov, N.R. and R. Tycko, Interview with Robert Tycko: On amyloids, Alzheimer disease, and solid-state NMR. Concepts in Magnetic Resonance Part A, 2015. 44(4): p. 182-189.

Friday, March 4, 2016

Solid-State Dynamic Nuclear Polarization at 9.4 and 18.8 T from 100 K to Room Temperature

This is an incredible article. It shows the temperature dependence of the DNP enhancement over a wide temperature regime. Most importantly it shows that at room temperature still an enhancement of 15-20 can be achieved.
Just a few years ago the common believe was that solid-state MAS-DNP experiments have to be performed at 90 K or below. This article clearly demonstrates that there is still so much room for improvements of DNP. I think the most exciting moments in DNP are still ahead of us and the method has the potential to become an integral part of the DNP toolbox.

Lelli, M., et al., Solid-State Dynamic Nuclear Polarization at 9.4 and 18.8 T from 100 K to Room Temperature. J Am Chem Soc, 2015. 137(46): p. 14558-61.

Efficient dynamic nuclear polarization (DNP) in solids, which enables very high sensitivity NMR experiments, is currently limited to temperatures of around 100 K and below. Here we show how by choosing an adequate solvent, (1)H cross effect DNP enhancements of over 80 can be obtained at 240 K. To achieve this we use the biradical TEKPol dissolved in a glassy phase of ortho-terphenyl (OTP). We study the solvent DNP enhancement of both TEKPol and BDPA in OTP in the range from 100 to 300 K at 9.4 and 18.8 T. Surprisingly, we find that the DNP enhancement decreases only relatively slowly for temperatures below the glass transition of OTP (Tg = 243 K), and (1)H enhancements around 15-20 at ambient temperature can be observed. We use this to monitor molecular dynamic transitions in the pharmaceutically relevant solids Ambroxol and Ibuprofen.

Wednesday, March 2, 2016

Support the #LEGO #NMR Spectrometer

You may have come across pictures of an NMR spectrometer made entirely of LEGO bricks. This is currently supported on the LEGO Ideas pages:

As of today the project has 2548 supporters and there are 135 days left to support the project. If the project receives 10000 supporters LEGO may come up with a small kit to build a spectrometer. Please consider supporting this effort.

PS: I was actually much more of a Fischer Technik guy when I grew up in Germany.

Solid-State NMR/Dynamic Nuclear Polarization of Polypeptides in Planar Supported Lipid Bilayers

Salnikov, E.S., et al., Solid-State NMR/Dynamic Nuclear Polarization of Polypeptides in Planar Supported Lipid Bilayers. J Phys Chem B, 2015. 119(46): p. 14574-83.

Dynamic nuclear polarization has been developed to overcome the limitations of the inherently low signal intensity of NMR spectroscopy. This technique promises to be particularly useful for solid-state NMR spectroscopy where the signals are broadened over a larger frequency range and most investigations rely on recording low gamma nuclei. To extend the range of possible investigations, a triple-resonance flat-coil solid-state NMR probe is presented with microwave irradiation capacities allowing the investigation of static samples at temperatures of 100 K, including supported lipid bilayers. The probe performance allows for two-dimensional separated local field experiments with high-power Lee-Goldberg decoupling and cross-polarization under simultaneous irradiation from a gyrotron microwave generator. Efficient cooling of the sample turned out to be essential for best enhancements and line shape and necessitated the development of a dedicated cooling chamber. Furthermore, a new membrane-anchored biradical is presented, and the geometry of supported membranes was optimized not only for good membrane alignment, handling, stability, and filling factor of the coil but also for heat and microwave dissipation. Enhancement factors of 17-fold were obtained, and a two-dimensional PISEMA spectrum of a transmembrane helical peptide was obtained in less than 2 h.