Wednesday, September 19, 2018

Water Dynamics from the Surface to the Interior of a Supramolecular Nanostructure #DNPNMR #ODNP

Ortony, Julia H., Baofu Qiao, Christina J. Newcomb, Timothy J. Keller, Liam C. Palmer, Elad Deiss-Yehiely, Monica Olvera de la Cruz, Songi Han, and Samuel I. Stupp. “Water Dynamics from the Surface to the Interior of a Supramolecular Nanostructure.” Journal of the American Chemical Society 139, no. 26 (July 5, 2017): 8915–21.


Water within and surrounding the structure of a biological system adopts context-specific dynamics that mediate virtually all of the events involved in the inner workings of a cell. These events range from protein folding and molecular recognition to the formation of hierarchical structures. Water dynamics are mediated by the chemistry and geometry of interfaces where water and biomolecules meet. Here we investigate experimentally and computationally the translational dynamics of vicinal water molecules within the volume of a supramolecular peptide nanofiber measuring 6.7 nm in diameter. Using Overhauser dynamic nuclear polarization relaxometry, we show that drastic differences exist in water motion within a distance of about one nanometer from the surface, with rapid diffusion in the hydrophobic interior and immobilized water on the nanofiber surface. These results demonstrate that water associated with materials designed at the nanoscale is not simply a solvent, but rather an integral part of their structure and potential functions.

Monday, September 17, 2018

Baudin, Mathieu, Basile Vuichoud, Aurélien Bornet, Geoffrey Bodenhausen, and Sami Jannin. “A Cryogen-Consumption-Free System for Dynamic Nuclear Polarization at 9.4 T.” Journal of Magnetic Resonance 294 (September 1, 2018): 115–21.


A novel system for dissolution dynamic nuclear polarization based on a cost-effective “cryogen-free” magnet that can generate fields up to 9.4 T with a sample space that can reach temperatures below 1.4 K in a continuous and stable manner. Polarization levels up to P(1H) = 60 ± 5% can be reached with TEMPOL in about 20 min, and P(13C) = 50 ± 5% can be achieved using adiabatic cross polarization.

Friday, September 14, 2018

13C → 1H transfer of light-induced hyperpolarization allows for selective detection of protons in frozen photosynthetic reaction center #DNPNMR

Bielytskyi, Pavlo, Daniel Gräsing, Kaustubh R. Mote, Karthick Babu Sai Sankar Gupta, Shimon Vega, P. K. Madhu, A. Alia, and Jörg Matysik. “13C → 1H Transfer of Light-Induced Hyperpolarization Allows for Selective Detection of Protons in Frozen Photosynthetic Reaction Center.” Journal of Magnetic Resonance 293 (August 1, 2018): 82–91.


In the present study, we exploit the light-induced hyperpolarization occurring on 13C nuclei due to the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect to boost the NMR signal intensity of selected protons via inverse cross-polarization. Such hyperpolarization transfer is implemented into 1H-detected two-dimensional 13C–1H correlation magic-angle-spinning (MAS) NMR experiment to study protons in frozen photosynthetic reaction centers (RCs). As a first trial, the performance of such an experiment is tested on selectively 13C labeled RCs from the purple bacteria of Rhodobacter sphaeroides. We observed response from the protons belonging to the photochemically active cofactors in their native protein environment. Such an approach is a potential heteronuclear spin-torch experiment which could be complementary to the classical heteronuclear correlation (HETCOR) experiments for mapping proton chemical shifts of photosynthetic cofactors and to understand the role of the proton pool around the electron donors in the electron transfer process occurring during photosynthesis.

Wednesday, September 12, 2018

Generating para-water from para-hydrogen: A Gedankenexperiment #DNPNMR

Ivanov, Konstantin L., and Geoffrey Bodenhausen. “Generating Para-Water from Para-Hydrogen: A Gedankenexperiment.” Journal of Magnetic Resonance 292 (July 1, 2018): 48–52.


A novel conceptual approach is described that is based on the transfer of hyperpolarization from para-hydrogen in view of generating a population imbalance between the two spin isomers of H2O. The approach is analogous to SABRE (Signal Amplification By Reversible Exchange) and makes use of the transfer of spin order from para-hydrogen to H2O in a hypothetical organometallic complex. The spin order transfer is expected to be most efficient at avoided level crossings. The highest achievable enrichment levels of para- and ortho-water are discussed.

Monday, September 10, 2018

Continuous hyperpolarization with parahydrogen in a membrane reactor #DNPNMR

Lehmkuhl, Sören, Martin Wiese, Lukas Schubert, Mathias Held, Markus Küppers, Matthias Wessling, and Bernhard Blümich. “Continuous Hyperpolarization with Parahydrogen in a Membrane Reactor.” Journal of Magnetic Resonance 291 (June 2018): 8–13. 


Hyperpolarization methods entail a high potential to boost the sensitivity of NMR. Even though the ‘‘Signal Amplification by Reversible Exchange” (SABRE) approach uses para-enriched hydrogen, p-H2, to repeatedly achieve high polarization levels on target molecules without altering their chemical structure, such studies are often limited to batch experiments in NMR tubes. Alternatively, this work introduces a continuous flow setup including a membrane reactor for the p-H2, supply and consecutive detection in a 1 T NMR spectrometer. Two SABRE substrates pyridine and nicotinamide were hyperpolarized, and more than 1000-fold signal enhancement was found. Our strategy combines low-field NMR spectrometry and a membrane flow reactor. This enables precise control of the experimental conditions such as liquid and gas pressures, and volume flow for ensuring repeatable maximum polarization.

Friday, September 7, 2018

Diastereoisomers of L-proline-linked trityl-nitroxide biradicals: synthesis and effect of chiral configurations on exchange interactions #DNPNMR

Zhai, Weixiang, Yalan Feng, Huiqiang Liu, Antal Rockenbauer, Deni Mance, Shaoyong Li, Yuguang Song, Marc Baldus, and Yangping Liu. “Diastereoisomers of L-Proline-Linked Trityl-Nitroxide Biradicals: Synthesis and Effect of Chiral Configurations on Exchange Interactions.” Chemical Science 9, no. 19 (May 16, 2018): 4381–91.


The exchange (J) interaction of organic biradicals is a crucial factor controlling their physiochemical properties and potential applications and can be modulated by changing the nature of the linker. In the present work, we for the first time demonstrate the effect of chiral configurations of radical parts on the J values of trityl-nitroxide (TN) biradicals. Four diastereoisomers (TNT1, TNT2, TNL1 and TNL2) of TN biradicals were synthesized and purified by the conjugation of a racemic (R/S) nitroxide with the racemic (M/P) trityl radical viaL-proline. The absolute configurations of these diastereoisomers were assigned by comparing experimental and calculated electronic circular dichroism (ECD) spectra as (M, S, S) for TNT1, (P, S, S) for TNT2, (M, S, R) for TNL1 and (P, S, R) for TNL2. Electron paramagnetic resonance (EPR) results showed that the configuration of the nitroxide part instead of the trityl part is dominant in controlling the exchange interactions and the order of the J values at room temperature is TNT1 (252 G) > TNT2 (127 G) ≫ TNL2 (33 G) > TNL1 (14 G). Moreover, the J values of TNL1/TNL2 with the S configuration in the nitroxide part vary with temperature and the polarity of solvents due to their flexible linker, whereas the J values of TNT1/TNT2 are almost insensitive to these two factors due to the rigidity of their linkers. The distinct exchange interactions between TNT1,2 and TNL1,2 in the frozen state led to strongly different high-field dynamic nuclear polarization (DNP) enhancements with ε = 7 for TNT1,2 and 40 for TNL1,2 under 800 MHz DNP conditions.

Wednesday, September 5, 2018

Perspective of Overhauser dynamic nuclear polarization for the study of soft materials #DNPNMR

Biller, Joshua R., Ryan Barnes, and Songi Han. “Perspective of Overhauser Dynamic Nuclear Polarization for the Study of Soft Materials.” Current Opinion in Colloid & Interface Science 33 (January 1, 2018): 72–85.


Solution state Overhauser dynamic nuclear polarization (ODNP) has been studied for 60years, but only in recent years has found applications of broad interest to biophysical sciences of hydration dynamics (HD-ODNP) around biomolecules and surfaces. In this review we describe state-of-the-art HD-ODNP methods and experiments, and identify technological and conceptual advances necessary to broadly disseminate HD-ODNP, as well as broaden its scope. Specifically, incomplete treatment of the saturation factor leads to the use of high microwave powers that induce temperature-dependent effects in HD-ODNP that can be detrimental to the stability and property of the sample and/or data interpretation, and thus must be corrected for. Furthermore, direct measurements of the electron spin relaxation times for the nitroxide radical-based spin labels used in HD-ODNP have recently caught up with the ambient solution conditions of relevance to HD-ODNP experiment, allowing us to envision an explicit treatment of the saturation factor. This would enable “single-shot” HD-ODNP at one or two concentrations and power levels, cutting down experimental times from the typical hours to minutes. With the development of a user-friendly and robust operation, the application of HD-ODNP experiments can be broadened for the study of biomolecules, biomaterials, soft polymer materials (i.e. hydrogels) and surfaces. In fact, any hydrated materials that can be viably spin labeled can yield information on local water dynamics and interfaces, and so guide the design of soft materials for medical and pharmaceutical uses. A brief introduction to spin-labeling, and exemplary applications to soft materials is discussed to serve as inspiration for future studies.

Monday, September 3, 2018

Frequency-Swept Integrated and Stretched Solid Effect Dynamic Nuclear Polarization #DNPNMR

Can, T. V., J. E. McKay, R. T. Weber, C. Yang, T. Dubroca, J. van Tol, S. Hill, and R. G. Griffin. “Frequency-Swept Integrated and Stretched Solid Effect Dynamic Nuclear Polarization.” The Journal of Physical Chemistry Letters 9, no. 12 (June 21, 2018): 3187–92. 


We investigate a new time domain approach to dynamic nuclear polarization (DNP), the frequency-swept integrated solid effect (FS-ISE), utilizing a high power, broadband 94 GHz (3.35 T) pulse EPR spectrometer. The bandwidth of the spectrometer enabled measurement of the DNP Zeeman frequency/field profile that revealed two dominant polarization mechanisms, the expected ISE, and a recently observed mechanism, the stretched solid effect (S2E). At 94 GHz, despite the limitations in the microwave chirp pulse length (10 μs) and the repetition rate (2 kHz), we obtained signal enhancements up to ∼70 for the S2E and ∼50 for the ISE. The results successfully demonstrate the viability of the FS-ISE and S2E DNP at a frequency 10 times higher than previous studies. Our results also suggest that these approaches are candidates for implementation at higher magnetic fields.

Friday, August 31, 2018

Electron-driven spin diffusion supports crossing the diffusion barrier in MAS DNP #DNPNMR

Wittmann, Johannes J., Michael Eckardt, Wolfgang Harneit, and Björn Corzilius. “Electron-Driven Spin Diffusion Supports Crossing the Diffusion Barrier in MAS DNP.” Physical Chemistry Chemical Physics 20, no. 16 (2018): 11418–29.



Dynamic nuclear polarization (DNP) can be applied to enhance the sensitivity of solid-state NMR experiments by several orders of magnitude due to microwave-driven transfer of spin polarization from unpaired electrons to nuclei. While the underlying quantum mechanical aspects are sufficiently well understood on a microscopic level, the exact description of the large-scale spin dynamics, usually involving hundreds to thousands of nuclear spins per electron, is still lacking consensus. Generally, it is assumed that nuclear hyperpolarization can only be observed on nuclei which do not experience strong influence of the unpaired electrons and thus being significantly removed from the paramagnetic polarizing agents. At the same time, sufficiently strong hyperfine interaction is required for DNP transfer. Therefore, efficient nuclear spin diffusion from the strongly-interacting nuclei to the NMR-observable bulk is considered to be essential for efficient nuclear hyperpolarization. Based on experimental results obtained on the endohedral fullerene N@C60 as a polarizing agent sparsely diluted in C60, we discuss the effect of the spin-diffusion barrier. We introduce electron-driven spin diffusion (EDSD) as a novel mechanism for nuclear polarization transfer in the proximity of an electron spin which is particularly relevant under magic-angle spinning (MAS) DNP conditions.

Wednesday, August 29, 2018

Amplification of Dynamic Nuclear Polarization at 200 GHz by Arbitrary Pulse Shaping of the Electron Spin Saturation Profile #DNPNMR

Kaminker, Ilia, and Songi Han. “Amplification of Dynamic Nuclear Polarization at 200 GHz by Arbitrary Pulse Shaping of the Electron Spin Saturation Profile.” The Journal of Physical Chemistry Letters 9, no. 11 (June 7, 2018): 3110–15.


Dynamic nuclear polarization (DNP) takes center stage in nuclear magnetic resonance (NMR) as a tool to amplify its signal by orders of magnitude through the transfer of polarization from electron to nuclear spins. In contrast to modern NMR and electron paramagnetic resonance (EPR) that extensively rely on pulses for spin manipulation in the time domain, the current mainstream DNP technology exclusively relies on monochromatic continuous wave (CW) irradiation. This study introduces arbitrary phase shaped pulses that constitute a train of coherent chirp pulses in the time domain at 200 GHz (7 T) to dramatically enhance the saturation bandwidth and DNP performance compared to CW DNP, yielding up to 500-fold in NMR signal enhancements. The observed improvement is attributed to the recruitment of additional electron spins contributing to DNP via the cross-effect mechanism, as experimentally confirmed by two-frequency pump–probe electron–electron double resonance (ELDOR).

Monday, August 27, 2018

Direct observation of Ru-alkylidene forming into ethylene in ring-closing metathesis from hyperpolarized 1H NMR #DNPNMR

Kim, Yaewon, Chia-Hsiu Chen, and Christian Hilty. “Direct Observation of Ru-Alkylidene Forming into Ethylene in Ring-Closing Metathesis from Hyperpolarized 1H NMR.” Chemical Communications 54, no. 34 (2018): 4333–36.



Ring-closing metathesis was monitored using real-time NMR of 1H hyperpolarized olefins at room temperature. By applying a selective saturation to an observable intermediate, its protons were found to transfer to ethylene. The intermediate was thus identified as a Ru-alkylidene species, which appears in the ethylene formation pathway.

Friday, August 24, 2018

Dynamic Nuclear Polarization Opens New Perspectives for NMR Spectroscopy in Analytical Chemistry #DNPNMR

Plainchont, B., P. Berruyer, J. N. Dumez, S. Jannin, and P. Giraudeau. “Dynamic Nuclear Polarization Opens New Perspectives for NMR Spectroscopy in Analytical Chemistry.” Analytical Chemistry 90 (March 20, 2018): 3639–50.


Dynamic nuclear polarization (DNP) can boost sensitivity in nuclear magnetic resonance (NMR) experiments by several orders of magnitude. This Feature illustrates how the coupling of DNP with both liquid- and solid-state NMR spectroscopy has the potential to considerably extend the range of applications of NMR in analytical chemistry.

Wednesday, August 22, 2018

Using a local low rank plus sparse reconstruction to accelerate dynamic hyperpolarized 13C imaging using the bSSFP sequence

Milshteyn, Eugene, Cornelius von Morze, Galen D. Reed, Hong Shang, Peter J. Shin, Peder E. Z. Larson, and Daniel B. Vigneron. “Using a Local Low Rank plus Sparse Reconstruction to Accelerate Dynamic Hyperpolarized 13C Imaging Using the BSSFP Sequence.” Journal of Magnetic Resonance 290 (May 1, 2018): 46–59.

Acceleration of dynamic 2D (T2 Mapping) and 3D hyperpolarized 13C MRI acquisitions using the balanced steady-state free precession sequence was achieved with a specialized reconstruction method, based on the combination of low rank plus sparse and local low rank reconstructions. Methods were validated using both retrospectively and prospectively undersampled in vivo data from normal rats and tumor-bearing mice. Four-fold acceleration of 1–2 mm isotropic 3D dynamic acquisitions with 2–5 s temporal resolution and two-fold acceleration of 0.25–1 mm2 2D dynamic acquisitions was achieved. This enabled visualization of the biodistribution of [2-13C]pyruvate, [1-13C]lactate, [13C, 15N2]urea, and HP001 within heart, kidneys, vasculature, and tumor, as well as calculation of high resolution T2 maps.

Tuesday, August 21, 2018

[NMR] Postdoctoral position in EPR spectroscopy


Dear Colleagues:

The Department of Chemistry at the University of Virginia invites applications for a Postdoctoral Research Associate, who is excited about the opportunity to work in a dynamic and collaborative research environment. The successful candidate will participate in collaborative work in the Membrane Biology Center at the University of Virginia, and will be engaged in research directed at the molecular structure and dynamics of proteins that mediate neuronal exocytosis using modern pulse EPR spectroscopy.

This is a one year appointment; however appointment may be renewed for an additional two, one-year increments, contingent upon available funding and satisfactory performance.

Requirements for the position include the completion of a Ph.D. degree in Chemistry, Biochemistry or a related discipline by the appointment start date, and effective oral and written communication skills. The candidate must have a working knowledge of biochemical and molecular biological laboratory procedures, and should have expertise in the expression and purification of SNAREs or related proteins. The candidate is also expected to have expertise in magnetic resonance spectroscopy, with a familiarity of EPR spectroscopy and modern pulse EPR instrumentation. The successful candidate is also expected to help mentor undergraduates and graduate students in the laboratory. 

To apply, please submit a candidate profile on-line through Jobs@UVA (https://jobs.virginia.edu) and electronically attach the following: cover letter, curriculum vitae, and the contact information for three (3) references; search on posting number 0623594. 

Review of applications will begin July 16, 2018; however, the position will remain open until filled. 

Questions regarding this position should be directed to: 
Prof. David Cafiso 
(434) 924-3067 

Questions regarding the Candidate Profile process or Jobs@UVA should be directed to: 
askHR@virginia.edu or 434-9982-0123 

The University will perform background checks on all new hires prior to making a final offer of employment. 

The University of Virginia is an affirmative action/equal opportunity employer committed to diversity, equity, and inclusiveness. Women Minorities, Veterans and Persons with Disabilities are encouraged to apply. 


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[NMR] Postdoctoral position in NMR of materials for energy storage at UCSB (Santa Barbara, USA)



Postdoctoral position in NMR of materials for energy storage at UCSB (Santa Barbara, USA)

The postdoctoral research position is based at the Materials Department, University of California Santa Barbara (UCSB), in the group of Prof. Raphaële Clément. The position is available from October, 1st, 2018, with an initial one-year contract renewable upon mutual agreement for two additional years.


Project Description

The research program focuses on the study of paramagnetic rechargeable battery materials using a variety of solid-state NMR (and EPR) techniques. The work will be in close collaboration with the Lawrence Berkeley National Laboratory, as well as other U.S. Universities and research groups at UCSB. In addition to developing a deep understanding of structure-property relationships for battery electrode materials, the postdoctoral researcher will be given the opportunity to acquire new experimental skills such as the solid-state synthesis of electrodes, and the preparation and testing of electrochemical cells. A strong emphasis will be placed on the combined use of experimental and theoretical tools to investigate changes in the local structure and electrochemical processes taking place during charge and discharge. Specifically, the interpretation of experimental paramagnetic NMR (and EPR) data will be assisted by first principles calculations of paramagnetic NMR/EPR parameters (an area of expertise of our group), and by insights gained from Monte Carlo and density functional theory simulations of electrode materials at different stages of the charge/discharge cycle (through ongoing collaborations). 
Relevant publications

[1] Lee, J.; Kitchaev, D. A.; Kwon, D.-H.; Lee, C.-W.; Papp, J. K.; Liu, Y.-S.; Lun, Z.; Clément, R. J.; Shi, T.; McCloskey, B. D.; Guo, J.; Balasubramanian, M.; Ceder, G. Nature 2018, 556 (7700), 185.

[2] Lee, J.; Papp, J. K.; Clément, R. J.; Sallis, S.; Kwon, D.-H.; Shi, T.; Yang, W.; McCloskey, B. D.; Ceder, G. Nat. Commun. 2017, 8 (1), 981.

[3] Kitchaev, D. A.; Lun, Z.; Richards, W. D.; Ji, H.; Clément, R. J.; Balasubramanian, M.; Kwon, D.-H.; Dai, K.; Papp, J. K.; Lei, T.; McCloskey, B. D.; Yang, W.; Lee, J.; Ceder, G. Energy Environ. Sci. 2018, 104, 4271.

[4] Clément, R. J.; Pell, A. J.; Middlemiss, D. S.; Strobridge, F. C.; Miller, J. K.; Whittingham, M. S.; Emsley, L.; Grey, C. P.; Pintacuda, G. J. Am. Chem. Soc. 2012, 134 (41), 17178.

[5] Middlemiss, D. S.; Ilott, A. J.; Clément, R. J.; Strobridge, F. C.; Grey, C. P. Chem. Mater. 2013, 25 (9), 1723.
Requirements and Preferred Experience

The requirements for the position are a Ph.D. in Chemistry, Materials Science, Physics or Engineering, and experience with standard solid-state NMR techniques (e.g. CP/MAS, REDOR, etc.). Experience with paramagnetic NMR and/or EPR is a plus. In addition to performing research, the postdoc will be expected to provide assistance with the training of graduate and undergraduate students.

The Magnetic Resonance Facilities at UCSB

The spectroscopy facility of the Materials Research Laboratory at UCSB (see https://www.mrl.ucsb.edu/spectroscopy-facility/instruments) comprises an X-band EPR spectrometer as well as several solid-state NMR spectrometers, including a 300 MHz system equipped with a MRI/diffusion probe, a 400 MHz DNP-NMR spectrometer, and 500 MHz and 800 MHz systems. All spectrometers are equipped with a range of MAS probes, with a fast spinning 1.3 mm probe (60 kHz MAS) available on the 500 MHz system. In addition, the Terahertz facility at UCSB (http://www.itst.ucsb.edu) is uniquely equipped with a high field high power EPR system.


Additional Information

Interested candidates should send a cover letter, a résumé (including a list of publications), and the names and email addresses of at least two references to rclement@ucsb.edu.
---------------------------------------------------------------------------
Raphaële Clément

Assistant Professor, Materials Department
Materials Research Laboratory, Room 3009
University of California, Santa Barbara, CA 93106-5121

Phone: 805-893-4294



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[NMR] postdoctoral position at UC Santa Cruz

Dear Colleagues,
I am please to announce the opening of a postdoctoral researcher position in the Department of Chemistry and Biochemistry at UC Santa Cruz. The selected individual should have demonstrated expertise in Double Electron-Electron Resonance (DEER) EPR. Research will focus on structural biology issues related to neurodegenerative diseases, as well as the facilitation of diverse collaborative studies among California Bay Area labs including UCSF, UC Merced, UC Davis and Stanford. Please see our website: 

and the job posting: 
With best regards,
glenn


Glenn L. Millhauser
Department of Chemistry & Biochemistry
UC Santa Cruz
Santa Cruz, CA 95064
831 459 2176 voice
831 566 3337 cell
831 459 2935 fax





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Monday, August 20, 2018

Effect of water/glycerol polymorphism on dynamic nuclear polarization #DNPNMR

Leavesley, Alisa, Christopher B. Wilson, Mark Sherwin, and Songi Han. “Effect of Water/Glycerol Polymorphism on Dynamic Nuclear Polarization.” Physical Chemistry Chemical Physics 20, no. 15 (April 18, 2018): 9897–9903.


A paramount feature of robust experimental methods is acquiring consistent data. However, in dynamic nuclear polarization (DNP), it has been observed that the DNP-induced NMR signal enhancement of nominally the same sample can vary between different experimental sessions. We investigated the impact of various freezing conditions on the DNP results for a standard sample, a 50/40/10 by volume d8-glycerol/D2O/H2O solution of 40 mM 4-amino TEMPO, and found that annealing the samples 10 K above the glass transition temperature (Tg) causes significant changes to the DNP profiles and enhancements compared to that in rapidly frozen samples. When varying the glycerol composition to yield a solution of 60/30/10 d8-glycerol/D2O/H2O, the DNP performance became markedly more consistent, even for samples prepared under vastly different sample freezing methods, in stark contrast with that of the 50/40/10 solution. The EPR lineshapes, Tm, and glass transition temperature, Tg, were measured under the same sample and experimental conditions as used for the DNP experiments to support the conclusion that different freezing methods change the distribution of 4-amino TEMPO radials in the 50/40/10 solution due to the formation of different polymorphs of the glass, which is mitigated in the 60/30/10 solution and is consistent with the water/glycerol vitrification literature.

Friday, August 17, 2018

Dynamic Nuclear Polarization Surface Enhanced NMR spectroscopy (DNP SENS): Principles, protocols, and practice #DNPNMR

Liao, Wei-Chih, Behnaz Ghaffari, Christopher P. Gordon, Jun Xu, and Christophe Copéret. “Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS): Principles, Protocols, and Practice.” Current Opinion in Colloid & Interface Science 33 (January 1, 2018): 63–71.


Dynamic Nuclear Polarization Surface Enhanced NMR spectroscopy has been demonstrated to significantly improve NMR sensitivity on materials by 1 to 2 orders of magnitude at high magnetic fields. The preferential surface enhancement also allows for selectively probing the solid surface. In this review, we will briefly describe the main mechanism used nowadays, i.e. cross effect, for DNP enhanced solid-state NMR. We will show the typical protocols of sample formulation leading to effective DNP surface enhancements and the key experimental factors in performing DNP SENS experiments. Other important developments in DNP, i.e. shielded polarizing agents for reactive surfaces, hyperpolarizing solid matrices, and high-temperature and high-field DNP, will be discussed as well. Finally, we close the review with a short summary and our perspectives on the directions of future developments in this field.

Wednesday, August 15, 2018

Considering low-rank, sparse and gas-inflow effects constraints for accelerated pulmonary dynamic hyperpolarized 129Xe MRI

Xiao, Sa, He Deng, Caohui Duan, Junshuai Xie, Huiting Zhang, Xianping Sun, Chaohui Ye, and Xin Zhou. “Considering Low-Rank, Sparse and Gas-Inflow Effects Constraints for Accelerated Pulmonary Dynamic Hyperpolarized 129Xe MRI.” Journal of Magnetic Resonance 290 (May 1, 2018): 29–37.


Dynamic hyperpolarized (HP) 129Xe MRI is able to visualize the process of lung ventilation, which potentially provides unique information about lung physiology and pathophysiology. However, the longitudinal magnetization of HP 129Xe is nonrenewable, making it difficult to achieve high image quality while maintaining high temporal-spatial resolution in the pulmonary dynamic MRI. In this paper, we propose a new accelerated dynamic HP 129Xe MRI scheme incorporating the low-rank, sparse and gas-inflow effects (L + S + G) constraints. According to the gas-inflow effects of HP gas during the lung inspiratory process, a variable-flip-angle (VFA) strategy is designed to compensate for the rapid attenuation of the magnetization. After undersampling k-space data, an effective reconstruction algorithm considering the low-rank, sparse and gas-inflow effects constraints is developed to reconstruct dynamic MR images. In this way, the temporal and spatial resolution of dynamic MR images is improved and the artifacts are lessened. Simulation and in vivo experiments implemented on the phantom and healthy volunteers demonstrate that the proposed method is not only feasible and effective to compensate for the decay of the magnetization, but also has a significant improvement compared with the conventional reconstruction algorithms (P-values are less than 0.05). This confirms the superior performance of the proposed designs and their ability to maintain high quality and temporal-spatial resolution.

Monday, August 13, 2018

Magic angle spinning NMR with metallized rotors as cylindrical microwave resonators #DNPNMR

Scott, Faith J., Erika L. Sesti, Eric J. Choi, Alexander J. Laut, Jagadishwar R. Sirigiri, and Alexander B. Barnes. “Magic Angle Spinning NMR with Metallized Rotors as Cylindrical Microwave Resonators.” Magnetic Resonance in Chemistry, May 16, 2018.


We introduce a novel design for millimeter wave electromagnetic structures within magic angle spinning (MAS) rotors. In this demonstration, a copper coating is vacuum deposited onto the outside surface of a sapphire rotor at a thickness of 50 nanometers. This thickness is sufficient to reflect 197 GHz microwaves, yet not too thick as to interfere with radiofrequency fields at 300 MHz or prevent sample spinning due to eddy currents. Electromagnetic simulations of an idealized rotor geometry show a microwave quality factor of 148. MAS experiments with sample rotation frequencies of ωr/2π = 5.4 kHz demonstrate that the drag force due to eddy currents within the copper does not prevent sample spinning. Spectra of sodium acetate show resolved 13C J-couplings of 60 Hz and no appreciable broadening between coated and uncoated sapphire rotors, demonstrating that the copper coating does not prevent shimming and high-resolution NMR spectroscopy. Additionally, 13C Rabi nutation curves of ω1/2π = 103 kHz for both coated and uncoated rotors indicate no detrimental impact of the copper coating on radiofrequency coupling of the nuclear spins to the sample coil. We present this metal coated rotor as a first step towards an MAS resonator. MAS resonators are expected to have a significant impact on developments in electron decoupling, pulsed DNP, room temperature DNP, DNP with low power microwave sources, and EPR detection.

[NMR] DNP postdoctoral position at UCSD

The Debelouchina lab at the University of California, San Diego is looking for a postdoctoral researcher with experience and/or interest in DNP to join our growing team. The position will involve the development of new DNP biradical polarization agents and their application to biological systems and materials. Candidates must hold a Ph.D. in chemistry, physics or a related discipline and have experience in solid-state NMR, hyperpolarization techniques or EPR. The project will take advantage of a new 600 MHz DNP spectrometer, scheduled for installation in the fall of 2018.

In addition, the University of California, San Diego has outstanding resources for high-field NMR spectroscopy, including 900 MHz, 750 MHz, 700 MHz and 500 MHz solid-state NMR spectrometers equipped with MAS and static probes, as well as solution spectrometers operating at 800 MHz, 600 MHz and 500 MHz dedicated to biomolecular NMR applications. The large UCSD scientific community and several research institutes nearby (The Salk Institute for Biological Studies, the Scripps Research Institute and the Sanford Burnham Prebys Medical Discovery Institute) provide a vast network and potential for collaborations and scientific exchange. In addition to a vibrant scientific environment, San Diego also offers beautiful weather all year round and many opportunities for nature and ocean exploration.

Interested candidates should contact Dr. Debelouchina directly at gdebelouchina@ucsd.edu with a cover letter, CV and email addresses of two references.

Representative publications:

  • Debelouchina GT, Bayro MJ, Fitzpatrick AWP, Ladizhansky V, Colvin MT, Caporini MA, Jaroniec CP, Bajaj VS, Rosay M, MacPhee C, Vendruscolo M, Maas WE, Dobson CM, Griffin RG (2013). Higher Order Amyloid Fibril Structure by MAS NMR and DNP Spectroscopy. J. Am. Chem. Soc. 135, 19237-47.
  • Debelouchina GT, Bayro MJ, van der Wel PCA, Caporini MA, Barnes AB, Rosay M, Maas WE, Griffin RG (2010). Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy of GNNQQNY Crystals and Amyloid Fibrils. Phys. Chem. Chem. Phys. 12, 5911-9.
  • Hu KN, Debelouchina GT, Smith AA, Griffin RG (2011). Quantum Mechanical Theory of Dynamic Nuclear Polarization in Solid Dielectrics. J. Chem. Phys. 134, 125105.
  • Dane EL, Maly T, Debelouchina GT, Griffin RG, Swager TM (2009). Synthesis of a BDPA-TEMPO Biradical. Org. Lett. 11, 1871-4.
___________________________
Galia Debelouchina, Ph.D.
Assistant Professor
Department of Chemistry and Biochemistry
University of California, San Diego
9500 Gilman Drive
La Jolla, CA 92093











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A message from the International EPR Society

Below is a message from the International EPR Society to members for the EPR and Magnetic Resonance Community. I typically don't post these kind of advertisements but I do believe the International EPR Society has done a lot of great work for the community over the many years.

Take a look at https://www.ieprs.org. Membership fees are very low and the EPR Newsletter is a nice treat.



Dear EPR users,

To continue to have a vibrant, diverse, and active EPR community, we will all benefit from a scientific organization that offers a support and communication infrastructure for EPR -- this is what the International EPR Society (https://www.ieprs.org) aspires to offer. 

The most familiar faces of IES may be the EPR Newsletters and the Silver and Gold Medals for EPR. 

IES is the only international scientific organization that represents the whole range of important research fields of electron paramagnetic resonance (EPR) spectroscopy and EPR imaging (EMRI). These methods are used as the main research tools over a very wide range of fields, including physics, chemistry, life sciences, materials research and medicine.

IES is a world-wide association of scientists, and the IES mailing list serves the community to help spread EPR-related information (jobs, post-doc and PhD positions, conferences, etc.) to the world-wide EPR community. It provides public networking, available to IES members, where one can post messages via the EPR Newsletter (EPRNL), the official IES publication. EPRNL not only provides information on the availability of second-hand EPR instrumentation, it also publishes advertisements of prominent manufacturers of EPR instrumentation.

Members of IES have free access to the EPRNL! See: http://www.epr-newsletter.ethz.ch

IES also awards prizes and honors for outstanding contributions to EPR spectroscopy, from senior to young investigators! The newly created IES poster prizes honor excellent young scientists and PhD students for their contributions to international EPR conferences. All these achievements are reported in the EPRNL, and you can find more about "Why IES" here: http://www.ieprs.org/whyjoin.php

The member fees are encouragingly low: $6/year for students, $12/year for emeritus and post-doctoral fellows, and $36/year for full members. We will be happy if you paid the membership dues for several years. See: http://www.apes-ies2018.org/registration
Your membership of the IES is what will keep IES relevant, vibrant and impactful, and give IES the necessary tools to be responsive to the ever emerging field of EPR spectroscopy. 

Sincerely,
Songi Han, Vice President (America) of IES
Thomas Prisner, President of IES

Friday, August 3, 2018

High-Resolution 2D NMR of Disordered Proteins Enhanced by Hyperpolarized Water

Szekely, O., G. L. Olsen, I. C. Felli, and L. Frydman. “High-Resolution 2D NMR of Disordered Proteins Enhanced by Hyperpolarized Water.” Analytical Chemistry, March 26, 2018.


This study demonstrates the usefulness derived from relying on hyperpolarized water obtained by dissolution DNP, for site-resolved biophysical NMR studies of intrinsically disordered proteins. Thanks to the facile amide-solvent exchange experienced by protons in these proteins, 2D NMR experiments that like HMQC rely on the polarization of the amide protons, can be enhanced using hyperpolarized water by several orders of magnitude over their conventional counterparts. Optimizations of the DNP procedure and of the subsequent injection into the protein sample are necessary to achieve these gains while preserving state-of-the-art resolution; procedures enabling this transfer of the hyperpolarized water and the achievement of foamless hyperpolarized protein solutions are demonstrated. These protocols are employed to collect 2D (15)N-(1)H HMQC NMR spectra of alpha-synuclein, showing residue-specific enhancements >/=100x over their thermal counterparts. These enhancements, however, vary considerably throughout the residues. The biophysics underlying this residue-specific behavior upon injection of hyperpolarized water is theoretically examined, the information that it carries is compared with results arising from alternative methods, and its overall potential is discussed.

Wednesday, August 1, 2018

Hyperpolarized Laplace NMR

Telkki, Ville-Veikko. “Hyperpolarized Laplace NMR.” Magnetic Resonance in Chemistry 0, no. 0 (2018).


Laplace nuclear magnetic resonance (NMR), dealing with NMR relaxation and diffusion experiments, reveals details of molecular motion and provides chemical resolution complementary to NMR spectra. Laplace NMR has witnessed a great progress in past decades due to the development of methodology and signal processing, and it has lots of extremely interesting applications in various fields, including chemistry, biochemistry, geology, archaeology, and medicine. The aim of this minireview is to give a pedagogically oriented overview of Laplace NMR. It does not provide a full literature review of the field, but, instead, it elucidate the benefits and features of Laplace NMR methods through few selected examples. The minireview describes also recent progress in multidimensional Laplace NMR and Laplace inversion methods. Furthermore, the potential of modern hyperpolarization methods as well as ultrafast approach to increase the sensitivity and time-efficiency of the Laplace NMR experiments is highlighted.

Monday, July 30, 2018

Biomolecular imaging of 13C-butyrate with dissolution-DNP: Polarization enhancement and formulation for in vivo studies

Flori, Alessandra, Giulio Giovannetti, Maria Filomena Santarelli, Giovanni Donato Aquaro, Daniele De Marchi, Silvia Burchielli, Francesca Frijia, Vincenzo Positano, Luigi Landini, and Luca Menichetti. “Biomolecular Imaging of 13C-Butyrate with Dissolution-DNP: Polarization Enhancement and Formulation for in Vivo Studies.” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 199 (June 15, 2018): 153–60.



Magnetic Resonance Spectroscopy of hyperpolarized isotopically enriched molecules facilitates the non-invasive real-time investigation of in vivo tissue metabolism in the time-frame of a few minutes; this opens up a new avenue in the development of biomolecular probes. Dissolution Dynamic Nuclear Polarization is a hyperpolarization technique yielding a more than four orders of magnitude increase in the 13C polarization for in vivo Magnetic Resonance Spectroscopy studies. As reported in several studies, the dissolution Dynamic Nuclear Polarization polarization performance relies on the chemico-physical properties of the sample. In this study, we describe and quantify the effects of the different sample components on the dissolution Dynamic Nuclear Polarization performance of [1-13C]butyrate. In particular, we focus on the polarization enhancement provided by the incremental addition of the glassy agent dimethyl sulfoxide and gadolinium chelate to the formulation. Finally, preliminary results obtained after injection in healthy rats are also reported, showing the feasibility of an in vivo Magnetic Resonance Spectroscopy study with hyperpolarized [1-13C]butyrate using a 3T clinical set-up.

[NMR] postdoctoral position at The City University of New York

We are seeking a Postdoctoral Research Scientist to investigate the molecular structure and biosynthesis of insoluble biopolymers involved in (a) deposition of melanin pigments within fungal cell walls and (b) protection of plants from desiccation and pathogenic attack. This NIH-funded position requires a Ph.D. in chemistry or biochemistry, with experience in the following prioritized areas: high-resolution solid and solution-state NMR, purification of cellular materials, design of bio-inspired polymeric materials. Also required are strong oral and written communication skills; self-motivation; technical troubleshooting aptitude; cooperative working style. Submit an application electronically to Dr. Ruth E. Stark, rstark@ccny.cuny.edu.

The City College of New York (CCNY) houses CUNY’s Macromolecular Assemblies Institute and hosts the world-class New York Structural Biology Center (NYSBC) on its campus. In 2015 our Biochemistry/Biophysics/Biodesign (B3) cluster moved to a new CCNY interdisciplinary science building adjoining the university’s Advanced Science Research Center (ASRC). CUNY’s research community includes several hundred chemists, biologists, physicists, medical researchers, and engineers who interact within a university network of 24 colleges and professional schools. Located in the historic Hamilton Heights – Sugar Hill section of upper Manhattan, CCNY is accessible by major subway and bus lines within the metropolitan New York area. Fringe benefits for this position include health insurance, life insurance, and a retirement account. 

The Stark research group makes extensive use of a 4-channel Agilent/Varian DirectDrive2 NMR spectrometer for solids and liquids (600 MHz) and has shared access to new Bruker NMR spectrometers (600, 700, 800 MHz) at the CUNY ASRC. Excellent Bruker NMR (500-900 MHz, liquids and solids) and 600 MHz DNP facilities are available on a rotating basis at the nearby NYSBC.

The City University of New York is an AA/ EO/ADA Employer.


--------------------------------------------------------------------------------------
Dr. Ruth E. Stark
Director, CUNY Institute for Macromolecular Assemblies
Distinguished Professor and Member of CUNY Doctoral Faculty
Professor and Chair, Department of Chemistry and Biochemistry, The City College of New York (CCNY)

Standard Mail: Marshak Science Building MR-1024
CCNY, 160 Convent Avenue
New York, NY 10031 USA

Packages: CDI Building 1.302
CCNY, ASRC, 85 Saint Nicholas Terrace
New York, NY 10031 USA

phone (212) 650-8916; FAX 212-650-6107



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Monday, July 23, 2018

[NMR] Research Fellow position at the University of Southampton

Research Fellow position at the University of Southampton, UK

We are looking for a Research Fellow in nuclear magnetic resonance (NMR) to work in the research group of Dr. Giuseppe Pileio (see https://generic.wordpress.soton.ac.uk/gpgroup/) and in collaboration with Prof. Malcolm H. Levitt on a project funded by EPSRC that concerns the development of NMR hardware and methodology to combine supercritical fluids, long-lived states NMR and dissolution-DNP in order to prolong the storage of hyperpolarised spin order and allow its transport from the production site to a remote location. 

The project is at its mid-point and we have already reached important milestones. We have built a lot of equipment to prepare and handle supercritical fluids in NMR and we have acquired an enormous quantity of data that clearly demonstrate the possibility to extend the storage time of spin polarisation when singlet-state methodology is coupled with the use of liquified gases and supercritical fluids. We entered now the second phase of the project where we will need to couple these methods to dissolution-DNP techniques, which will be the main outcome of the project and the purpose or the job here advertised.

In such context, you will help to develop new research ideas and applications exploiting the interfaces of singlet-magnetic resonance, DNP and supercritical fluids and will contribute to the design and set up of NMR experiments, numerical data analysis software and NMR methodology. 

The closing date for the application is 10 Aug 2018 with interviews in late August. The position is officially available from 1st September 2018 but other arrangements can be discussed.

For more details on the project and how to apply see: https://jobs.soton.ac.uk/Vacancy.aspx?ref=1032518EB

Chemistry at the University of Southampton provides an excellent environment for personal deveopment. The department was ranked 6th for research intensity and 8th for research power in the 2014 Research Excellence Framework. The magnetic resonance section (see https://www.southampton.ac.uk/magres) in Chemistry offers a variety of facilities and complimentary expertise that includes solid-state NMR, bioNMR, microfluidics and MRI. Facilities includes a 300MHz, two 400MHz, a 500MHz, three 600MHz and a 700MHz NMR magnets with equipment that allows solid-state, liquid state and micro-imaging applications. An EPR instrument is also available as well as a state-of-art dynamic nuclear (DNP) polariser. The University offer access to complimentary techniques including X-Ray, micro-CT, IR and MS. 

At the University of Southampton, we value diversity and equality.

I am happy to discuss any further detail with interested candidates!

Dr. Giuseppe Pileio, PhD

Lecturer in Physical Chemistry,
Department of Chemistry,
Building 27 - Room 2059, 
University of Southampton,
University Road, SO17 1BJ,
Internal Post Code: M16,
Southampton, Hampshire, UK.

Tel.: +44 (023) 80 59 4160
ORCID: 0000-0001-9223-3896

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Direct (17)O dynamic nuclear polarization of single-site heterogeneous catalysts #DNPNMR

Perras, F. A., K. C. Boteju, Slowing, A. D. Sadow, and M. Pruski. “Direct (17)O Dynamic Nuclear Polarization of Single-Site Heterogeneous Catalysts.” Chem Commun (Camb) 54 (April 3, 2018): 3472–75.


We utilize direct 17O DNP for the characterization of non-protonated oxygens in heterogeneous catalysts. The optimal sample preparation and population transfer approach for 17O direct DNP experiments performed on silica surfaces is determined and applied to the characterization of Zr- and Y-based mesoporous silica-supported single-site catalysts.

Friday, July 20, 2018

Quantum-rotor-induced polarization

Meier, Benno. “Quantum-Rotor-Induced Polarization.” Magnetic Resonance in Chemistry 0, no. 0 (2018).


Quantum-rotor-induced polarization is closely related to para-hydrogen-induced polarization. In both cases, the hyperpolarized spin order derives from rotational interaction and the Pauli principle by which the symmetry of the rotational ground state dictates the symmetry of the associated nuclear spin state. In quantum-rotor-induced polarization, there may be several spin states associated with the rotational ground state, and the hyperpolarization is typically generated by hetero-nuclear cross-relaxation. This review discusses preconditions for quantum-rotor-induced polarization for both the 1-dimensional methyl rotor and the asymmetric rotor H217O@C60, that is, a single water molecule encapsulated in fullerene C60. Experimental results are presented for both rotors.

Wednesday, July 18, 2018

Dynamic Nuclear Polarization NMR Spectroscopy of Polymeric Carbon Nitride Photocatalysts: Insights into Structural Defects and Reactivity #DNPNMR

Li, Xiaobo, Ivan V. Sergeyev, Fabien Aussenac, Anthony F. Masters, Thomas Maschmeyer, and James M. Hook. “Dynamic Nuclear Polarization NMR Spectroscopy of Polymeric Carbon Nitride Photocatalysts: Insights into Structural Defects and Reactivity.” Angewandte Chemie International Edition, May 8, 2018.


Metal-free polymeric carbon nitrides (PCNs) are promising photocatalysts for solar hydrogen production, but their structurephotoactivity relationship remains elusive. Here, we characterize two PCNs by dynamic nuclear polarization-enhanced solid-state NMR spectroscopy, that circumvents the need for specific labeling with either 13C- or 15N-enriched precursors. This allows rapid 1-D and 2-D data acquisition, providing insights into the structural contrasts of the PCNs. Compared to PCN_B with lower performance, PCN_P, the porous and more active photocatalyst, is richer in terminal Nhydrogens not associated with inter-polymer chains, which are further proposed to act as efficient carrier traps and reaction sites.

Monday, July 16, 2018

Stable Isotope-Resolved Analysis with Quantitative Dissolution Dynamic Nuclear Polarization

Lerche, M. H., D. Yigit, A. B. Frahm, J. H. Ardenkjaer-Larsen, R. M. Malinowski, and P. R. Jensen. “Stable Isotope-Resolved Analysis with Quantitative Dissolution Dynamic Nuclear Polarization.” Analytical Chemistry 90 (January 2, 2018): 674–78. 


Metabolite profiles and their isotopomer distributions can be studied noninvasively in complex mixtures with NMR. The advent of dissolution Dynamic Nuclear Polarization (dDNP) and isotope enrichment add sensitivity and resolution to such metabolic studies. Metabolic pathways and networks can be mapped and quantified if protocols that control and exploit the ex situ signal enhancement are created. We present a sample preparation method, including cell incubation, extraction and signal enhancement, to obtain reproducible and quantitative dDNP (qdDNP) NMR-based stable isotope-resolved analysis. We further illustrate how qdDNP was applied to gain metabolic insights into the phenotype of aggressive cancer cells.

Friday, July 13, 2018

Reversal of Paramagnetic Effects by Electron Spin Saturation #DNPNMR

Jain, Sheetal K., Ting A. Siaw, Asif Equbal, Christopher B. Wilson, Ilia Kaminker, and Songi Han. “Reversal of Paramagnetic Effects by Electron Spin Saturation.” The Journal of Physical Chemistry C 122, no. 10 (March 15, 2018): 5578–89.


We present a study in which both significant dynamic nuclear polarization (DNP) enhancement of 7Li NMR and reversal of the paramagnetic effects (PEs) are achieved by microwave (μw) irradiation-induced electron spin saturation of nitroxide radicals at liquid-helium temperatures. The reversal of the PE was manifested in significant narrowing of the 7Li NMR line and reversal of the paramagnetic chemical shift under DNP conditions. The extent of the PE was found to decrease with increased saturation of the electron paramagnetic resonance line, modulated as a function of microwave (μw) power, frequency, duration of irradiation, and gating time between μw irradiation and NMR detection. The defining observation was the shortening of the electron phase memory time, Tm, of the excited observer spins with increasing μw irradiation and concurrent electron spin saturation of the electron spin bath. This and a series of corroborating studies reveal the origin of the NMR line narrowing to be the reversal of paramagnetic relaxation enhancement (PRE), leading us to debut the term REversal of PRE by electron Spin SaturatION (REPRESSION). The shortening of electron Tm of any paramagnetic system as a function of electron spin saturation has not been reported to date, making REPRESSION a discovery of this study. The reversal of the paramagnetic dipolar shift is due to the decrease in electron spin order, also facilitated by electron spin saturation. This study offers new fundamental insights into PE under DNP conditions and a method to detect and identify NMR signal proximal to paramagnetic sites with reduced or minimal line broadening.

Wednesday, July 11, 2018

Hyperpolarized NMR: d-DNP, PHIP, and SABRE

Kovtunov, Kirill Viktorovich, Ekaterina Pokochueva, Oleg Salnikov, Samuel Cousin, Dennis Kurzbach, Basile Vuichoud, Sami Jannin, et al. “Hyperpolarized NMR: D-DNP, PHIP, and SABRE.” Chemistry – An Asian Journal 0, no. ja (2018).


NMR signals intensities can be enhanced by several orders of magnitude via utilization of techniques for hyperpolarization of different molecules, and it allows one to overcome the main sensitivity challenge of modern NMR/MRI techniques. Hyperpolarized fluids can be successfully used in different applications of material science and biomedicine. This focus review covers the fundamentals of the preparation of hyperpolarized liquids and gases via dissolution dynamic nuclear polarization (d-DNP) and parahydrogen-based techniques such as signal amplification by reversible exchange (SABRE) and parahydrogen-induced polarization (PHIP) in both heterogeneous and homogeneous processes. The different novel aspects of hyperpolarized fluids formation and utilization along with the possibility of NMR signal enhancement observation are described.

Monday, July 9, 2018

Applications of dissolution dynamic nuclear polarization in chemistry and biochemistry

Zhang, Guannan, and Christian Hilty. “Applications of Dissolution Dynamic Nuclear Polarization in Chemistry and Biochemistry.” Magnetic Resonance in Chemistry 0, no. 0 (2018). 


Sensitivity of detection is one of the most limiting aspects when applying NMR spectroscopy to current problems in the molecular sciences. A number of hyperpolarization methods exist for increasing the population difference between nuclear spin Zeeman states and enhance the signal-to-noise ratio by orders of magnitude. Among these methods, dissolution dynamic nuclear polarization (D-DNP) is unique in its capability of providing high spin polarization for many types of molecules in the liquid state. Originally proposed for biomedical applications including in vivo imaging, applications in high resolution NMR spectroscopy are now emerging. These applications are the focus of the present review. Using D-DNP, a small sample aliquot is first hyperpolarized as a frozen solid at low temperature, followed by dissolution into the liquid state. D-DNP extends the capabilities of liquid state NMR spectroscopy towards shorter timescales and enables the study of nonequilibrium processes, such as the kinetics and mechanisms of reactions. It allows the determination of intermolecular interactions, in particular based on spin relaxation parameters. At the same time, a challenge in the application of this hyperpolarization method is that spin polarization is nonrenewable. Substantial effort has been devoted to develop methods for enabling rapid correlation spectroscopy, the measurement of time-dependent signals, and the extension of the observable time window. With these methods, D-DNP has the potential to open new application areas in the chemical and biochemical sciences.

Friday, July 6, 2018

Many-body kinetics of dynamic nuclear polarization by the cross effect #DNPNMR

Karabanov, A., D. Wiśniewski, F. Raimondi, I. Lesanovsky, and W. Köckenberger. “Many-Body Kinetics of Dynamic Nuclear Polarization by the Cross Effect.” Physical Review A 97 (26 2018): 031404.


Dynamic nuclear polarization (DNP) is an out-of-equilibrium method for generating nonthermal spin polarization which provides large signal enhancements in modern diagnostic methods based on nuclear magnetic resonance. A particular instance is cross-effect DNP, which involves the interaction of two coupled electrons with the nuclear spin ensemble. Here we develop a theory for this important DNP mechanism and show that the nonequilibrium nuclear polarization buildup is effectively driven by three-body incoherent Markovian dissipative processes involving simultaneous state changes of two electrons and one nucleus.We identify different parameter regimes for effective polarization transfer and discuss under which conditions the polarization dynamics can be simulated by classical kinetic Monte Carlo methods. Our theoretical approach allows simulations of the polarization dynamics on an individual spin level for ensembles consisting of hundreds of nuclear spins. The insight obtained by these simulations can be used to find optimal experimental conditions for cross-effect DNP and to design tailored radical systems that provide optimal DNP efficiency.

Wednesday, July 4, 2018

Dynamic Nuclear Polarization-Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic-Angle Spinning #DNPNMR

Jaudzems, Kristaps, Andrea Bertarello, Sachin R. Chaudhari, Andrea Pica, Diane Cala-De Paepe, Emeline Barbet-Massin, Andrew J. Pell, et al. “Dynamic Nuclear Polarization-Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic-Angle Spinning.” Angewandte Chemie 0 (2018).


Dynamic nuclear polarization (DNP) is a powerful way to overcome the sensitivity limitation of magic?angle?spinning (MAS) NMR experiments. However, the resolution of the DNP?NMR spectra of proteins is compromised by severe line broadening associated with the necessity to perform experiments at cryogenic temperatures and in the presence of paramagnetic radicals. High?quality DNP?enhanced NMR spectra of the Acinetobacter phage 205 (AP205) nucleocapsid can be obtained by combining high magnetic field (800?MHz) and fast MAS (40?kHz). These conditions yield enhanced resolution and long coherence lifetimes allowing the acquisition of resolved 2D correlation spectra and of previously unfeasible scalar?based experiments. This enables the assignment of aromatic resonances of the AP205 coat protein and its packaged RNA, as well as the detection of long?range contacts, which are not observed at room temperature, opening new possibilities for structure determination.

Tuesday, July 3, 2018


Postdoctoral Position:

Development of Pulsed High-Field EPR Methods and Applications
Location: National High Magnetic Field Laboratory, Tallahassee, FL
Application Deadline: Until the position is filled

A postdoctoral position is available in the Electron Magnetic Resonance (EMR) group at the National High Magnetic Field Laboratory (NHMFL). The position will be focused on development of pulsed high-field EPR methods and applications at W-band (94 GHz) and potentially higher frequencies. The successful candidate will have at her or his disposal a state-of-the-art high-power (1 kW peak) W-band spectrometer developed at the University of St. Andrews.1 This instrument offers true nanosecond time resolution and wideband excitation (1 GHz instantaneous bandwidth), facilitating complex pulse programming and arbitrary waveform generation, thus enabling a suite of multi-dimensional electron- (and electron-nuclear) magnetic resonance methodologies. Applicants should be comfortable working on hardware development. However, the end-goal centers on the materials and biological applications.

The EMR facility additionally boasts a wide range of other unique pulsed and continuous wave high-field EPR instruments spanning the range from 9 GHz to 2.5 THz, and magnetic fields up to 45 T. The group comprises six faculty-level researchers, an engineer who assists with instrument development, as well as a cohort of graduate students and postdocs. The group also has strong interactions with EPR and NMR experts in chemistry and biology at both Florida State University and the University of Florida in Gainesville. Further information concerning the NHMFL EMR group, including links to recent publications, can be found at:

http://magnet.fsu.edu/usershub/scientificdivisions/emr/index.html

Minimum qualifications include a Ph.D. in Physics, Chemistry, or a related discipline. Experience in one or more of the following areas is preferred, but not essential: EPR spectroscopy, particularly pulsed and/or high-field EPR; instrument design/development (radio frequency, microwave, software/hardware interface…); biological or materials EPR applications. Questions regarding the position should be directed to the EMR Director, Stephen Hill (shill@magnet.fsu.edu). To apply, please send a CV, a cover letter describing your experience and research interests, and the contact information for three references, preferably by email to:

Morgan Fitch, Administrative Support Assistant

National High Magnetic Field Laboratory

1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA

Email: mfitch@magnet.fsu.edu (with cc. to shill@magnet.fsu.edu)

The NHMFL is operated for the US National Science Foundation by a collaboration of institutions comprising Florida State University, the University of Florida, and Los Alamos National Laboratory. https://nationalmaglab.org/

Florida State University is an Equal Opportunity/Access/Affirmative Action/Pro Disabled & Veteran Employer. http://www.hr.fsu.edu/PDF/Publications/diversity/EEO_Statement.pdf

1Cruikshank et al., Rev. Sci. Inst. 80, 103102 (2009); https://doi.org/10.1063/1.3239402

Monday, July 2, 2018

Biomolecular imaging of (13)C-butyrate with dissolution-DNP: Polarization enhancement and formulation for in vivo studies

Flori, A., G. Giovannetti, M. F. Santarelli, G. D. Aquaro, D. De Marchi, S. Burchielli, F. Frijia, V. Positano, L. Landini, and L. Menichetti. “Biomolecular Imaging of (13)C-Butyrate with Dissolution-DNP: Polarization Enhancement and Formulation for in Vivo Studies.” Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy 199 (June 15, 2018): 153–60.


Magnetic Resonance Spectroscopy of hyperpolarized isotopically enriched molecules facilitates the non-invasive real-time investigation of in vivo tissue metabolism in the time-frame of a few minutes; this opens up a new avenue in the development of biomolecular probes. Dissolution Dynamic Nuclear Polarization is a hyperpolarization technique yielding a more than four orders of magnitude increase in the (13)C polarization for in vivo Magnetic Resonance Spectroscopy studies. As reported in several studies, the dissolution Dynamic Nuclear Polarization polarization performance relies on the chemico-physical properties of the sample. In this study, we describe and quantify the effects of the different sample components on the dissolution Dynamic Nuclear Polarization performance of [1-(13)C]butyrate. In particular, we focus on the polarization enhancement provided by the incremental addition of the glassy agent dimethyl sulfoxide and gadolinium chelate to the formulation. Finally, preliminary results obtained after injection in healthy rats are also reported, showing the feasibility of an in vivo Magnetic Resonance Spectroscopy study with hyperpolarized [1-(13)C]butyrate using a 3T clinical set-up.

Friday, June 29, 2018

Paramagnetic metal ion dopants as polarization agents for DNP NMR spectroscopy in inorganic solids #DNPNMR

Chakrabrty Tanmoy, Goldin Nir, Feintuch Akiva, Houben Lothar, and Leskes Michal. “Paramagnetic Metal Ion Dopants as Polarization Agents for DNP NMR Spectroscopy in Inorganic Solids.” ChemPhysChem 0, no. ja (May 17, 2018).



Dynamic nuclear polarization (DNP), a technique in which the high electron spin polarization is transferred to surrounding nuclei via microwaves irradiation, equips solid state NMR spectroscopy with unprecedented sensitivity. The most commonly used polarization agents for DNP are nitroxide radicals. However, their applicability to inorganic materials is mostly limited to surface detection. Paramagnetic metal ions were recently introduced as alternatives for nitroxides. Doping inorganic solids with paramagnetic ions can be used to tune material properties and introduces endogenous DNP agents that can potentially provide sensitivity in the particles' bulk and surface. Here we demonstrate the approach by doping Li4Ti5O12 (LTO), an anode material for lithium ion batteries, with paramagnetic ions. By incorporating Gd(III) and Mn(II) in LTO we gain up to 14 fold increase in signal intensity in static 7Li DNP?NMR experiments. These results suggest that doping with paramagnetic ions provides an efficient route for sensitivity enhancement in the bulk of micron size particles.

[NMR] DNP NMR postdoc position at NHMFL, Tallahassee, FL #DNPNMR

Postdoctoral Position:

Development of High-Field Solution-State Overhauser DNP NMR Spectroscopy

Location: National High Magnetic Field Laboratory, Tallahassee, FL

Application Deadline: Until the position is filled 
A postdoctoral position is available, starting Fall 2018, at the U.S. National High Magnetic Field Laboratory (NHMFL) in Tallahassee Florida to carry out research on Overhauser Dynamic Nuclear Polarization (ODNP) NMR at high field (14.1 T). This position is fully funded for a period of 3 years by the National Science Foundation. For this research project, the NHMFL facility is equipped with a 600 MHz solution-state NMR spectrometer and a matching 395 GHz Gyrotron. We seek highly motivated applicants to work with the NHMFL DNP group to develop and implement new methods and experimental applications needed for enabling ODNP NMR spectroscopy of small to medium-sized molecules. The resulting solution-state ODNP NMR experiments will have applications in chemistry and biochemistry, particularly for characterizing limited quantities of molecules from natural product and pharmaceutical chemistry, from petroleum and polymer analytical chemistry, from food and environmental sciences, and from metabolomics.

The successful candidate will be involved in collaborative research with other experts at the NHMFL working in chemical and physical applications of ODNP NMR, as well as advanced microwave and RF instrumentation and technology. He/she will work within a team that consists of the faculty and engineers in the NMR and EPR divisions. Minimum qualifications include a Ph.D. in Chemistry, Physics or a related discipline related to advanced NMR. Experience in experimental NMR methods is essential and in DNP and/or EPR is expected. 

This position will remain available until filled. To apply, please send a CV, a cover letter describing your experience and research interests, and contact information for three references to:


Sungsool Wi

National High Magnetic Field laboratory
1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA
Tel: 850-645-2770

The NHMFL is operated for the National Science Foundation by a collaboration of institutions comprising Florida State University, the University of Florida, and Los Alamos National Laboratory. https://nationalmaglab.org/

Florida State University (FSU) is an Equal Opportunity/Access/Affirmative Action/Pro Disabled & Veteran Employer. http://www.hr.fsu.edu/PDF/Publications/diversity/EEO_Statement.pdf
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Thursday, June 28, 2018

[NMR] Postdoc Positions in DNP at ETH

Dear Colleagues,

there are two postdoctoral positions open at ETH Zurich in the field of DNP in the groups of Sebastian Kozerke and Matthias Ernst.

The first positions concerns Magnetic Resonance (MR) pulse sequence design, image reconstruction and data analysis approaches for Dynamic Nuclear Polarization (DNP) based hyperpolarized imaging of cardiac perfusion and metabolism on experimental MR equipment: https://apply.refline.ch/845721/6341/pub/1/index.html It will be based at the Institut for Biomedical Engineering (Sebastian Kozerke, http://www.cmr.ethz.ch).

The second position concerns the development of Dynamic Nuclear Polarization (DNP) based hyperpolarized methods for in-vitro and in-vivo imaging purposes. Project foci are on DNP hardware development and optimization as well as on novel materials for hyperpolarized imaging including nanoparticles for in-vivo imaging applications:
It will be based at the Laboratory for Physical Chemistry (Matthias Ernst,

Both positions are part of a long-standing collaboration between the two groups and close collaboration with students and postdocs in both groups is expected. In the past we have developed three DNP polarizers at 3.4 and 7 T field which can be used with NMR systems and a small animal imaging systems. The group of Sebastian Kozerke also has a SpinLab polarizer for clinical imaging systems available.

More information can be found online under the above mentioned links. For detailed questions about the two positions, please contact Sebastian Kozerke (kozerke@biomed.ee.ethz.ch) or Matthias Ernst (maer@ethz.ch). Applications for the two positions can be submitted online using the above mentioned links.

Best regards,
Matthias Ernst

-- 
+----------------------------------------+-----------------------------------+
| Matthias Ernst | Phone: +41-44-632-4366 |
| ETH Zürich, HCI D 227 | Fax: +41-44-632-1621 |
| Laboratorium für Physikalische Chemie | |
| Wolfgang-Pauli-Strasse 10 | Email: maer@ethz.ch |
| CH-8093 Zürich, Switzerland | maer@gmx.ch |
+----------------------------------------+-----------------------------------+

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[NMR] Post Doc Position in Biomolecular Solid-State NMR at USC, Los Angeles

Dear Colleagues,

The Siemer lab at USC is looking for a post-doctoral associate with a background in NMR spectroscopy and knowledge of protein biochemical techniques. The lab studies the structure and dynamics, of functional and toxic amyloid fibrils. To this goal, we apply solid-state NMR spectroscopy together with other biochemical and biophysical methods.

The Siemer lab is part of the Protein Structure Center at USC and works in close collaboration wit the EPR lab of Ralf Langen and liquid-state NMR lab of Tobias Ulmer as part of an effort to investigate nervous system function with biophysical methods in an interdisciplinary environment.

The position is available immediately. Interested candidates should send their CV's including the names of three references to Ansgar Siemer asiemer@usc.edu.
-- 
Ansgar B Siemer 
Assistant Professor,
Physiology & Neuroscience
Zilkha Neurogenetic Institute
Keck School of Medicine of USC
1501 San Pablo Street, ZNI 119F
Los Angeles, CA 90033
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[NMR] Associate Research Engineer position at BASF (Ludwigshafen/Germany)


Dear colleague,

BASF has an opening for an Associate Research Engineer at the interface of Solid-State NMR and Surface Spectroscopy.

The position will be associated with Dr. Sabine Hirth (Surface Analytics by XPS and ToF-SIMS) and Dr. Karsten Seidel (Solid-State NMR). We are two teams in the Structures & Surfaces group at BASF’s Department of Material Physics & Analytics. We are part of a central research platform which serves the entire BASF community. The new team member shall strengthen our efforts in the characterization of inorganic materials, in particular battery materials, as well as other complex materials, using multi-method approaches in both labs and beyond.

Please note: this position aims at a permanent lab-based employment, and is typically addressing scientists with a Master’s degree (or Bachelor’s degree + job experience). PhD graduates may want to apply for “Research Scientist” or “Laborleiter” positions on careers.basf.com.

Having a good command of the German language is not a prerequisite, and actually, scientific reporting at BASF is preferably done in English. However, it is generally very helpful to know or quickly learn German. In fact, the job posting is currently available only in German:


[in case the link does not work, please go to careers.basf.com and search jobs for “NMR”]

Job profile (translation of selected items):

Self-dependent experimental work in projects as well as routine analytical services
Adaptation and development of methods to characterize materials, such as battery materials
Methods development using complex analytical techniques with X-ray-Photoelectron-, Mass- and NMR-Spectrometers
Study of scientific literature, active learning from others
Presentation of work in project meetings, authoring of comprehensive lab reports

Your profile (translation of selected items):

Degree in chemistry, physics, or a related field of science (Master’s degree, or comparable qualification, such as Bachelor’s degree plus adequate job experience, or „Chemotechniker“ plus adequate job experience)
Advanced knowledge of inorganic chemistry
Experience with instrumental analytics, preferably XPS, ToF-SIMS, NMR
Interest to permanently work in the field of analytics and analytical methods development
You have been actively performing complex data analysis using advanced IT tools, including an understanding of the mathematical background
Very good communication skills, as well as an independent and target-oriented style of work

We are looking forward to receiving your application through careers.basf.com. (Further inquiries may be sent to karsten.seidel@basf.com, applications will be accepted through the job portal.)

We are located at BASF’s headquarters in Ludwigshafen/Germany. Ludwigshafen is a twin city with Mannheim, other cities close by are Heidelberg, Karlsruhe, Darmstadt, Worms, and Neustadt an der Weinstraße. Frankfurt is less than 1h from here. The region is known e.g. for its chemical, pharmaceutical, automotive and construction industry, as well as for its beautiful surrounding, such as the Palatinate forest and the Odenwald forest, with its modest climate and popular vineyards.

With best regards,

Sabine Hirth & Karsten Seidel

BASF SE, Registered Office: 67056 Ludwigshafen, Germany 
Registration Court: Amtsgericht Ludwigshafen, Registration No.: HRB 6000 
Chairman of the Supervisory Board: Juergen Hambrecht 
Board of Executive Directors:
Martin Brudermueller, Chairman; Hans-Ulrich Engel, Vice Chairman; 
Saori Dubourg, Sanjeev Gandhi, Michael Heinz, Markus Kamieth, Wayne T. Smith

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