Friday, November 17, 2017

High-resolution hyperpolarized in vivo metabolic 13C spectroscopy at low magnetic field (48.7mT) following murine tail-vein injection


Coffey, A.M., et al., High-resolution hyperpolarized in vivo metabolic 13C spectroscopy at low magnetic field (48.7mT) following murine tail-vein injection. J. Magn. Reson., 2017. 281(Supplement C): p. 246-252.


High-resolution 13C NMR spectroscopy of hyperpolarized succinate-1-13C-2,3-d2 is reported in vitro and in vivo using a clinical-scale, biplanar (80cm-gap) 48.7mT permanent magnet with a high homogeneity magnetic field. Non-localized 13C NMR spectra were recorded at 0.52MHz resonance frequency over the torso of a tumor-bearing mouse every 2s. Hyperpolarized 13C NMR signals with linewidths of ∼3Hz (corresponding to ∼6ppm) were recorded in vitro (2mL in a syringe) and in vivo (over a mouse torso). Comparison of the full width at half maximum (FWHM) for 13C NMR spectra acquired at 48.7mT and at 4.7T in a small-animal MRI scanner demonstrates a factor of ∼12 improvement for the 13C resonance linewidth attainable at 48.7mT compared to that at 4.7T in vitro. 13C hyperpolarized succinate-1-13C resonance linewidths in vivo are at least one order of magnitude narrower at 48.7mT compared to those observed in high-field (≥3T) studies employing HP contrast agents. The demonstrated high-resolution 13C in vivo spectroscopy could be useful for high-sensitivity spectroscopic studies involving monitoring HP agent uptake or detecting metabolism using HP contrast agents with sufficiently large 13C chemical shift differences.

Wednesday, November 15, 2017

Ramped-amplitude NOVEL #DNPNMR


Can, T.V., et al., Ramped-amplitude NOVEL. J. Chem. Phys., 2017. 146(15): p. 154204.


We present a pulsed dynamic nuclear polarization (DNP) study using a ramped-amplitude nuclear orientation via electron spin locking (RA-NOVEL) sequence that utilizes a fast arbitrary waveform generator (AWG) to modulate the microwave pulses together with samples doped with narrow-line radicals such as 1,3-bisdiphenylene-2-phenylallyl (BDPA), sulfonated-BDPA (SA-BDPA), and trityl- OX063. Similar to ramped-amplitude cross polarization in solid-state nuclear magnetic resonance, RA-NOVEL improves the DNP efficiency by a factor of up to 1.6 compared to constant-amplitude NOVEL (CA-NOVEL) but requires a longer mixing time. For example, at mix = 8 s, the DNP efficiency reaches a plateau at a ramp amplitude of 20 MHz for both SA-BDPA and trityl-OX063, regardless of the ramp profile (linear vs. tangent). At shorter mixing times (mix = 0.8 s), we found that the tangent ramp is superior to its linear counterpart and in both cases there exists an optimum ramp size and therefore ramp rate. Our results suggest that RA-NOVEL should be used instead of CA-NOVEL as long as the electronic spin lattice relaxation T1e is sufficiently long and/or the duty cycle of the microwave amplifier is not exceeded. To the best of our knowledge, this is the first example of a time domain DNP experiment that utilizes modulated microwave pulses. Our results also suggest that a precise modulation of the microwave pulses can play an important role in optimizing the efficiency of pulsed DNP experiments and an AWG is an elegant instrumental solution for this purpose.

Monday, November 13, 2017

Anisotropic longitudinal electronic relaxation affects DNP at cryogenic temperatures #DNPNMR

Anisotropic relaxation effects are well know and understood in EPR spectroscopy and have long served as measures to understand the motion (libration) of paramagnetic co-factors (quinones, nitroxide radicals etc.) in biological system. In this study the authors investigate the effect of anisotropic relaxation effects in DNP experiments.

To find more about anisotropic relaxation effects studied by EPR take a look at the work by Sergei Dzuba or the Eatons:


Weber, E.M.M., et al., Anisotropic longitudinal electronic relaxation affects DNP at cryogenic temperatures. Phys. Chem. Chem. Phys., 2017. 19(24): p. 16087-16094.


We report the observation of anisotropic longitudinal electronic relaxation in nitroxide radicals under typical dynamic nuclear polarization conditions. This anisotropy affects the efficiency of dynamic nuclear polarization at cryogenic temperatures of 4 K and high magnetic fields of 6.7 T. Under our experimental conditions, the electron paramagnetic resonance spectrum of nitroxides such as TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl) is only partly averaged by electronic spectral diffusion, so that the relaxation times T1e([small omega]) vary across the spectrum. We demonstrate how the anisotropy of T1e([small omega]) can be taken into account in simple DNP models.

Friday, November 10, 2017

Natural Abundance 17 O DNP NMR Provides Precise O-H Distances and Insights into the Bronsted Acidity of Heterogeneous Catalysts #DNPNMR


Perras, F.A., et al., Natural Abundance 17 O DNP NMR Provides Precise O-H Distances and Insights into the Bronsted Acidity of Heterogeneous Catalysts. Angew Chem Int Ed Engl, 2017. 56(31): p. 9165-9169.

https://www.ncbi.nlm.nih.gov/pubmed/28499071

Heterogeneous Bronsted acid catalysts are tremendously important in industry, particularly in catalytic cracking processes. Here we show that these Bronsted acid sites can be directly observed at natural abundance by 17 O DNP surface-enhanced NMR spectroscopy (SENS). We additionally show that the O-H bond length in these catalysts can be measured with sub-picometer precision, to enable a direct structural gauge of the lability of protons in a given material, which is correlated with the pH of the zero point of charge of the material. Experiments performed on materials impregnated with pyridine also allow for the direct detection of intermolecular hydrogen bonding interactions through the lengthening of O-H bonds.

Research Faculty I, 12 Month Salaried (NHMFL) #DNPNMR

Research Faculty I, 12 Month Salaried (NHMFL)

For more information follow this link: Faculty Position

Research Faculty I, 12 Month Salaried (NHMFL)

Job ID
42607

Location
Tallahassee, FL

Full/Part Time
Full-Time

Regular/Temporary
Regular

Apply On Or Before
12/13/2017

Department
National High Magnetic Field Laboratory (NHMFL)

Responsibilities
This position will be part of a major initiative involving Dynamic Nuclear Polarization (DNP) including magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy. Position will be focused primarily on, but not limited to the operation of the MAS-DNP NMR spectrometer. The research faculty is expected to develop independent and collaborative research in chemical, biological, and material applications of DNP as well as DNP instrumentation and technology. They will work within a team of faculty and engineers through the NMR, EMR and AMRIS programs and in collaboration with users of the NHMFL facilities. A Bruker 600MHz DNP system equipping a 600MHz field-sweepable wide-bore magnet had been installed and is fully operational.

Qualifications
Ph.D. in Chemistry, Physics, Biology, or a related discipline. Experience in DNP and NMR (or EPR).

Expert knowledge in both experimental and theoretical fields in NMR spectroscopy and DNP.
Knowledge of Linux-based computer systems and networks, as it is the operating system of the spectrometer and requires collaborative research with users in various areas locally and remotely.
Computer simulation skills, which are indispensable in interpreting the spectra at the DNP and NMR domains.

Preferred
Electron paramagentic resonance (EPR) spectroscopy.

Contact Info
For additional information, please contact Bettina Roberson at roberson@magnet.fsu.edu.

Pay Plan
This is a Faculty position.

Criminal Background Check
This position requires successful completion of a criminal history background check.

How To Apply
If qualified and interested in a specific job opening as advertised, apply to Florida State University at https://jobs.fsu.edu. If you are a current FSU employee, apply via myFSU > Self Service.

Applicants are required to complete the online application with all applicable information. Applications must include all work history up to ten years, and education details even if attaching a resume.

Equal Employment Opportunity
An Equal Opportunity/Access/Affirmative Action/Pro Disabled & Veteran Employer.

FSU's Equal Opportunity Statement can be viewed at: http://www.hr.fsu.edu/PDF/Publications/diversity/EEO_Statement.pdf

Wednesday, November 8, 2017

In Silico Design of DNP Polarizing Agents: Can Current Dinitroxides Be Improved? #DNPNMR


Perras, F.A., A. Sadow, and M. Pruski, In Silico Design of DNP Polarizing Agents: Can Current Dinitroxides Be Improved? ChemPhysChem, 2017. 18(16): p. 2279-2287.


Numerical calculations of enhancement factors offered by dynamic nuclear polarization in solids under magic angle spinning (DNP-MAS) were performed to determine the optimal EPR parameters for a dinitroxide polarizing agent. We found that the DNP performance of a biradical is more tolerant to the relative orientation of the two nitroxide moieties than previously thought. Generally, any condition in which the gyy tensor components of both radicals are perpendicular to one another is expected to have near-optimal DNP performance. Our results highlight the important role of the exchange coupling, which can lessen the sensitivity of DNP performance to the inter-radical distance, but also lead to lower enhancements when the number of atoms in the linker becomes less than three. Lastly, the calculations showed that the electron T1e value should be near 500 mus to yield optimal performance. Importantly, the newest polarizing agents already feature all of the qualities of the optimal polarizing agent, leaving little room for further improvement. Further research into DNP polarizing agents should then target non-nitroxide radicals, as well as improvements in sample formulations to advance high-temperature DNP and limit quenching and reactivity.

Tuesday, November 7, 2017

[NMR] postdoctoral position in solid-state NMR of proteins

Colleagues,

We have an opening for a postdoc to join our group at University of Massachusetts Amherst, to use solid-state NMR and other biophysical methods to study the structure and dynamics of bacterial chemotaxis receptor protein complexes. This NIH-funded project combines biochemical methods to assemble and characterize native-like functional complexes of these proteins in defined signaling states, with a variety of biophysical methods including solid-state NMR and hydrogen exchange mass spectrometry to determine what changes are involved in signal propagation. See for example our recent publications:


We are especially interested in individuals with 
- enthusiastic interest in mechanistic studies of membrane proteins and protein complexes
- experience with protein expression and purification
- experience with solid-state NMR of proteins

Our lab is part of an interactive community of research groups working with a suite of instruments recently purchased by the new UMass Institute for Applied Life Sciences in the NMR Facility, Biophysical Characterization Facility, and other Core Facilities. UMass Amherst is located along with 4 other colleges in the Pioneer Valley of western Massachusetts, a great place to live and work, and centrally located about 3 hours from New York and 2 hours from Boston.

To apply, candidates should send the following to thompson@chem.umass.edu
- A cover letter that describes your relevant experience, research interests, and career goals.
- CV including the names and contact information of 2-3 references

Lynmarie K Thompson, PhD
Professor
Department of Chemistry, 122 LGRT
University of Massachusetts Amherst
710 North Pleasant St.
Amherst, MA 01003-9336


Office LGRT 864: 413-545-0827
Lab LGRT 820: 413-545-4983


Director, Chemistry Biology Interface Training Program


Molecular and Cellular Biology: http://www.bio.umass.edu/mcb/
Institute for Applied Life Sciences: https://www.umass.edu/ials/

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Monday, November 6, 2017

13C Dynamic Nuclear Polarization Using Derivatives of TEMPO Free Radical #DNPNMR


Niedbalski, P., et al., 13C Dynamic Nuclear Polarization Using Derivatives of TEMPO Free Radical. Appl. Magn. Reson., 2017. 48(9): p. 933-942.


The nitroxide-based 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) free radical is widely used in 13C dynamic nuclear polarization (DNP) due to its relatively low cost, commercial availability, and effectiveness as polarizing agent. While a large number of TEMPO derivatives are available commercially, so far, only few have been tested for use in 13C DNP. In this study, we have tested and evaluated the 13C hyperpolarization efficiency of eight derivatives of TEMPO free radical with different side arms in the 4-position. In general, these TEMPO derivatives were found to have slight variations in efficiency as polarizing agents for DNP of 3 M [1-13C] acetate in 1:1 v/v ethanol:water at 3.35 T and 1.2 K. X-band electron paramagnetic resonance (EPR) spectroscopy revealed no significant differences in the spectral features among these TEMPO derivatives. 2H enrichment of the ethanol:water glassing matrix resulted in further improvement of the solid-state 13C DNP signals by factor of 2 to 2.5-fold with respect to the 13C DNP signal of non-deuterated DNP samples. These results suggest an interaction between the nuclear Zeeman reservoirs and the electron dipolar system via the thermal mixing mechanism.

Friday, November 3, 2017

[NMR] Application deadline reminder: 2018 Winter School on Biomolecular Solid-State NMR: Jan 7-12 in Stowe,…


This is just a friendly reminder that the application deadline for the SSNMR winter school is approaching at the end of this week (please see the original announcement below for details of the winter school and how to apply).

Announcement

The 5th U.S.-Canada Winter School on Biomolecular Solid-State NMR
Stowe, Vermont, USA
January 7-12, 2018

Organizers: Tatyana Polenova (U. Delaware), Christopher Jaroniec (Ohio State U.), Mei Hong (MIT) and Bob Griffin (MIT)

Dear Colleagues,

We invite you to encourage your students, postdocs, and senior associates to attend the 5th Winter School on Biomolecular Solid-State NMR, which will be held on January 7-12, 2018, in Stowe, Vermont. Similar to the previous four highly successful Winter Schools, this pedagogical meeting is aimed at students and postdocs in solid-state NMR as well as more senior scientists in related fields who are interested in entering this vibrant field. Our goals are to provide a focused week of teaching of the core concepts and practices in the increasingly multifaceted and complex field of biological solid-state NMR spectroscopy, and to encourage information sharing among different laboratories. Topics to be covered in the 5th Winter School include:

  • Basics of solid-state NMR: orientation-dependent NMR frequencies, MAS, tensors and rotations, density operator and its time evolution, decoupling and recoupling techniques, and average Hamiltonian theory
  • Multidimensional correlation spectroscopy, non-uniform sampling, techniques for resonance assignment and measurement of structural restraints in biomolecules 
  • Paramagnetic solid-state NMR techniques
  • Techniques for enhancing sensitivity of solid-state NMR: dynamic nuclear polarization and 1H detection
  • Solid-state NMR techniques for measuring molecular motion
  • Solid-state NMR techniques for structural studies of oriented membrane proteins
  • Protein structure calculations in XPLOR-NIH
  • Beyond spin 1/2: NMR of quadrupolar nuclei 
  • Basics of NMR probe design 
In addition to lectures, problem sets and their discussion sessions will be given at the meeting.

Speakers: The following have agreed to serve as lecturers:

Tim Cross (Florida State)
Philip Grandinetti (Ohio State)
Bob Griffin (MIT)
Mei Hong (MIT)
Christopher Jaroniec (Ohio State)
Francesca Marassi (Burnham)
Ann McDermott (Columbia)
Stanley Opella (UC San Diego)
Guido Pintacuda (ENS Lyon)
Tatyana Polenova (Delaware)
Bernd Reif (Tech Univ Munich)
Charles Schwieters (NIH)
Robert Tycko (NIH)
Kurt Zilm (Yale)

Venue and transportation: The meeting will be held at the beautiful and historical Trapp Family Lodge http://www.trappfamily.com/ in Stowe, Vermont. Stowe is accessible from airports in Burlington, VT, Manchester, NH, and Boston, MA. A block of rooms has been reserved at the lodge. We anticipate space for ~70 attendees.

Cost: Room and board will be free for attendees. The registration fee is $500 for academic attendees and $750 for industrial attendees. 

Application: Interested students and postdocs should send the following application materials as a single PDF file to: ASC-WinterSchool2018@osu.edu. The application materials include: (1) a CV, (2) publication list, and (3) a 1-page description of your current research and your statement of interest in attending the Winter School. Please indicate your gender in the CV for the purpose of hotel room assignment. Please name this application file as AdvisorLastName_YourLastName_WS2018app.pdf. For example “McDermott_ Smith_WS2018app.pdf”.

Application deadline: Friday, November 3, 2017. Given the limited number of available spaces, it may not be possible to accommodate applications received after this date. 

Please distribute this announcement to members of your research group as well as to colleagues who may be interested in attending or sending their group members.

With kind regards,
Tatyana, Chris, Mei & Bob

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The Atomic-Level Structure of Cementitious Calcium Silicate Hydrate


Kumar, A., et al., The Atomic-Level Structure of Cementitious Calcium Silicate Hydrate. The Journal of Physical Chemistry C, 2017. 121(32): p. 17188-17196.


Efforts to tune the bulk physical properties of concrete are hindered by a lack of knowledge related to the atomic-level structure and growth of calcium silicate hydrate phases, which form about 50–60% by volume of cement paste. Here we describe the first synthesis of compositionally uniform calcium silicate hydrate phases with Ca:Si ratios tunable between 1.0 and 2.0. The calcium silicate hydrate synthesized here does not contain a secondary Ca(OH)2 phase, even in samples with Ca:Si ratios above 1.6, which is unprecedented for synthetic calcium silicate hydrate systems. We then solve the atomic-level three-dimensional structure of these materials using dynamic nuclear polarization enhanced 1H and 29Si nuclear magnetic resonance experiments in combination with atomistic simulations and density functional theory chemical shift calculations. We discover that bridging interlayer calcium ions are the defining structural characteristic of single-phase cementitious calcium silicate hydrate, inducing the strong hydrogen bonding that is responsible for stabilizing the structure at high Ca:Si ratios.

Wednesday, November 1, 2017

Modeling of Polarization Transfer Kinetics in Protein Hydration Using Hyperpolarized Water


Kim, J., M. Liu, and C. Hilty, Modeling of Polarization Transfer Kinetics in Protein Hydration Using Hyperpolarized Water. The Journal of Physical Chemistry B, 2017. 121(27): p. 6492-6498.


Water–protein interactions play a central role in protein structure, dynamics, and function. These interactions, traditionally, have been studied using nuclear magnetic resonance (NMR) by measuring chemical exchange and nuclear Overhauser effect (NOE). Polarization transferred from hyperpolarized water can result in substantial transient signal enhancements of protein resonances due to these processes. Here, we use dissolution dynamic nuclear polarization and flow-NMR for measuring the pH dependence of transferred signals to the protein trypsin. A maximum enhancement of 20 is visible in the amide proton region of the spectrum at pH 6.0, and of 47 at pH 7.5. The aliphatic region is enhanced up to 2.3 times at pH 6.0 and up to 2.5 times at pH 7.5. The time dependence of these observed signals can be modeled quantitatively using rate equations incorporating chemical exchange to amide sites and, optionally, intramolecular NOE to aliphatic protons. On the basis of these two- and three-site models, average exchange (kex) and cross-relaxation rates (σ) obtained were kex = 12 s–1, σ = −0.33 s–1 for pH 7.5 and kex = 1.8 s–1, σ = −0.72 s–1 for pH 6.0 at a temperature of 304 K. These values were validated using conventional EXSY and NOESY measurements. In general, a rapid measurement of exchange and cross-relaxation rates may be of interest for the study of structural changes of the protein occurring on the same time scale. Besides protein–water interactions, interactions with cosolvent or solutes can further be investigated using the same methods.

Monday, October 30, 2017

Hyperpolarized 133Cs is a sensitive probe for real-time monitoring of biophysical environments


Karlsson, M., J.H. Ardenkjaer-Larsen, and M.H. Lerche, Hyperpolarized 133Cs is a sensitive probe for real-time monitoring of biophysical environments. Chemical Communications, 2017. 53(49): p. 6625-6628.


133Cs NMR is a valuable tool for non-invasive analysis of biological systems, where chemical shift and relaxation properties report on changes in the physical environment. Hyperpolarization can increase the liquid-state 133Cs NMR signal by several orders of magnitude and allow real-time monitoring of physical changes in cell based systems.

Friday, October 27, 2017

A novel THz-band double-beam gyrotron for high-field DNP-NMR spectroscopy


Idehara, T., et al., A novel THz-band double-beam gyrotron for high-field DNP-NMR spectroscopy. Review of Scientific Instruments, 2017. 88(9): p. 094708.


We present the first experimental results of the study on a novel second harmonic THz-band doublebeam gyrotron. The tube has demonstrated a stable single-mode operation with output parameters that are appropriate for the next-generation 1.2 GHz dynamic nuclear polarization-nuclear magnetic resonance spectroscopy. Besides the design mode (TE8,5), a series of other fundamental and second harmonic modes have been excited. This makes the new gyrotron a versatile radiation source, which can be used also in other applications of the high-power science and technologies.

Wednesday, October 25, 2017

Dynamic Nuclear Polarization of Long-Lived Nuclear Spin States in Methyl Groups


Dumez, J.-N., et al., Dynamic Nuclear Polarization of Long-Lived Nuclear Spin States in Methyl Groups. The Journal of Physical Chemistry Letters, 2017. 8(15): p. 3549-3555.


We have induced hyperpolarized long-lived states in compounds containing 13C-bearing methyl groups by dynamic nuclear polarization (DNP) at cryogenic temperatures, followed by dissolution with a warm solvent. The hyperpolarized methyl long-lived states give rise to enhanced antiphase 13C NMR signals in solution, which often persist for times much longer than the 13C and 1H spin–lattice relaxation times under the same conditions. The DNP-induced effects are similar to quantum-rotor-induced polarization (QRIP) but are observed in a wider range of compounds because they do not depend critically on the height of the rotational barrier. We interpret our observations with a model in which nuclear Zeeman and methyl tunnelling reservoirs adopt an approximately uniform temperature, under DNP conditions. The generation of hyperpolarized NMR signals that persist for relatively long times in a range of methyl-bearing substances may be important for applications such as investigations of metabolism, enzymatic reactions, protein–ligand binding, drug screening, and molecular imaging.

Monday, October 23, 2017

PhD scholarship in Metabolomics using Dissolution DNP-NMR

Detailed information can be found here: PhD Sholarship in dDNP


A PhD scholarship is available in the Centre for Hyperpolarization in Magnetic Resonance (HYPERMAG) at DTU Elektro, starting at the beginning of 2018. 


HYPERMAG is a Centre of Excellence founded by the Danish National Research Foundation. We conduct research in the field of biomedical engineering with the aim of conducting real time functional imaging by tracking metabolic processes with isotope labelled tracers. 


The centre specializes in a technology, hyperpolarization with dissolution dynamic nuclear polarization (dDNP), that produce signal enhancement on Nuclear Magnetic Resonance (NMR) by many orders of magnitude. This large signal increase allows direct detection of metabolism in living objects from cell to man. In the Biology group, in particularly, we focus on developing new applications that exploit signal-enhanced tracers in the observation of transient states in metabolic networks. 


The subject of the PhD project is stable isotope resolved metabolomics within the framework of dDNP NMR. The aim is to establish and execute data acquisition, analysis and interpretation strategies for quantitative dDNP NMR analysis of metabolites in cellular systems. Using the developed and demonstrated tools human tissue samples will be analysed with dDNP NMR and evaluated in the context of metabolomics research.

Responsibilities and tasks 

The PhD candidate will be working with interdisciplinary experimental research rooted in biophysics. 


The project will include: 

  • Establishment and validation of NMR acquisition strategy and data analysis methods 
  • Development of data interpretation methods for quantitative dissolution DNP NMR 
  • Demonstration of developed tools on metabolite extract data from pathogen-host bio-systems 
  • Ex vivo study of stable isotope resolved metabolism analysis using tissue samples. 

We seek an enthusiastic candidate with background in biotechnology, biophysics or equivalent to carry out this interdisciplinary project. Knowledge within dissolution DNP and NMR is preferred. Good communication skills in English, both written and spoken, are required. 

Qualifications 

Candidates should hold a MSc in engineering or a similar degree with an academic level equivalent to the MSc in engineering. 


Approval and Enrolment

The scholarship for the PhD degree are subject to academic approval, and the candidates will be enrolled in one of the general degree programmes of DTU. For information about the general requirements for enrolment and the general planning of the scholarship studies, please see the DTU PhD Guide: http://www.dtu.dk/english/Education/PhD/Rules/PhDguide.


Assessment

The assessment of the applicants will be made by Senior Scientist Mathilde Hauge Lerche and Associate Professor Pernille Rose Jensen. Final assessment will be on the basis of an interview. 


You are more than welcome to contact us by email: mhauler@elektro.dtu.dk


We offer

DTU is a leading technical university globally recognized for the excellence of its research, education, innovation and scientific advice. We offer a rewarding and challenging job in an international environment. We strive for academic excellence in an environment characterized by collegial respect and an academic freedom tempered by responsibility. 


Salary and appointment terms

The appointment will be based on the collective agreement with the Danish Confederation of Professional Associations. The allowance will be agreed with the relevant union. The period of employment is 3 years. 


You can read more about career paths at DTU here: http://www.dtu.dk/english/career/meet-our-people/career-paths.


Further information 

Further information may be obtained from Senior Scientist Mathilde Hauge Lerche, tel.: +45 5362 4555. 


You can read more about Center for Hyperpolarization in Magnetic Resonance on http://www.hypermag.dtu.dk.


Application

Please submit your online application no later than 5 November 2017 (Local time). Applications must be submitted as one pdf file containing all materials to be given consideration. To apply, please open the link "Apply online", fill in the online application form, and attach all your materials in English in one pdf file. 


The file must include: 




Candidates may apply prior to obtaining their MSc, but cannot begin before having received it. 


All qualified candidates irrespective of age, gender, race, disability, religion or ethnic background are encouraged to apply.

Direct Hyperpolarization of Nitrogen-15 in Aqueous Media with Parahydrogen in Reversible Exchange


Colell, J.F.P., et al., Direct Hyperpolarization of Nitrogen-15 in Aqueous Media with Parahydrogen in Reversible Exchange. J. Am. Chem. Soc., 2017. 139(23): p. 7761-7767.


Signal amplification by reversible exchange (SABRE) is an inexpensive, fast, and even continuous hyperpolarization technique that uses para-hydrogen as hyperpolarization source. However, current SABRE faces a number of stumbling blocks for translation to biochemical and clinical settings. Difficulties include inefficient polarization in water, relatively short-lived 1H-polarization, and relatively limited substrate scope. Here we use a water-soluble polarization transfer catalyst to hyperpolarize nitrogen-15 in a variety of molecules with SABRE-SHEATH (SABRE in shield enables alignment transfer to heteronuclei). This strategy works in pure H2O or D2O solutions, on substrates that could not be hyperpolarized in traditional 1H-SABRE experiments, and we record 15N T1 relaxation times of up to 2 min.

Friday, October 20, 2017

Dynamic nuclear polarization studies of nitroxyl spin probes in agarose gel using Overhauser-enhanced magnetic resonance imaging


Meenakumari, V., et al., Dynamic nuclear polarization studies of nitroxyl spin probes in agarose gel using Overhauser-enhanced magnetic resonance imaging. Magn Reson Chem, 2017. 55(11): p. 1022-1028.


Agarose is a tissue-equivalent material and its imaging characteristics similar to those of real tissues. Hence, the dynamic nuclear polarization studies of 3-carboxy-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (carboxy-PROXYL) in agarose gel were carried out. The dynamic nuclear polarization parameters such as spin lattice relaxation time, longitudinal relaxivity, leakage factor, saturation parameter and coupling parameter were estimated for 2 mM carboxy-PROXYL in phosphate-buffered saline solution and water/agarose mixture (99 : 1). From these results, the spin probe concentration was optimized as 2 mM, and the reduction in enhancement was observed for carboxy-PROXYL in water/agarose mixture (99 : 1) compared with phosphate-buffered saline solution. Phantom imaging was also performed with 2 mM concentration of carboxy-PROXYL in various concentrations of agarose gel at various radio frequency power levels. The results from the dynamic nuclear polarization measurements agree well with the phantom imaging results. These results pave the way for designing model system for human tissues suited to the biological applications of electron spin resonance/Overhauser-enhanced magnetic resonance imaging.

Thursday, October 19, 2017

[NMR] NMR Symposium at the 255th ACS meeting in New Orleans, March 18-22, 2018

Dear Colleagues,

Susannah Scott, Nancy Washton, and I are organizing a magnetic resonance symposium in the Division of Catalysis Science and Technology (CATL) at the 255th ACS meeting in New Orleans which will take place between March 18th and 22nd. The symposium is titled: "New Techniques and Applications of Magnetic Resonance Methods in Heterogeneous Catalysis" and will focus on the development and application of NMR/EPR methods for studying heterogeneous catalysts and catalytic processes. You can find the call for papers here:


and you can submit your abstracts here. Submission deadline is this Friday, October 20, 2017.


We encourage all interested researchers and students to submit an abstract and help make this inaugural symposium a success!

Best regards,

-- 

Frédéric Perras, PhD
Ames Laboratory
US Department of Energy
Ames, IA, 50011


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Wednesday, October 18, 2017

[NMR] Postodoctoral position available in solid-state NMR and DNP in Grenoble #DNPNMR

Postdoctoral Position available in solid-state NMR and DNP in Grenoble (France) ssNMR and DNP investigation of bacterial cell-wall

In this project innovative spectroscopic approaches including solid-state NMR and MAS-DNP will be developed and conducted to investigate the cell wall of mycobacteria and more specifically the role of key peptidoglycan cross-linking enzymes. 

This research will fit in a collaborative effort led by two internationally recognized NMR research groups in Grenoble, which covers a wide spectrum of competences going from high-field liquid-state NMR to advanced MAS-DNP. The team directed by Dr Jean-Pierre Simorre in the Biomolecular NMR Spectroscopy group at Institut de Biologie Structurale has a direct access to a state of the art NMR facility containing six high-field spectrometers (950 MHz, 850 MHz, 700 MHz, 3x600 MHz) equipped with latest solid-state NMR and cryogenic liquid-state probes. The DNP group of the Institute for Nanosciences and Cryogenics, directed by Gaël De Paëpe, hosts two 400-MHz MAS-DNP spectrometers (one equipped with a helium-recirculated cooling system) and is a pioneer in instrumentation and methods developments for MAS-DNP. 

Applicants are expected to have a doctoral experience in solid-state NMR spectroscopy with a strong interest in biomolecular systems. Knowledge in MAS-DNP will be considered as a plus. The successful candidate will be recruited for 24 months (12 months renewable once) funded by an ANR postdoctoral fellowship. Motivated candidates should send their application with a curriculum vitae, a letter of motivation, and the name of 2 referees by December 31st, 2017 via email to both Jean-Pierre Simorre (jean-pierre.simorre@ibs.fr) and Sabine Hediger (sabine.hediger@cea.fr).


Selected related publications from our groups:

1. Schanda P, Triboulet S, Laguri C, Bougault CM, Ayala I, Callon M, Arthur M, Simorre JP. (2014) J. Am. Chem. Soc. 136(51):17852-17860.

2. Takahashi H1, Ayala I, Bardet M, De Paëpe G, Simorre JP, Hediger S. (2013) J Am Chem Soc. 135(13):5105-5110.

3. Kern T, Giffard M, Hediger S, Amoroso A, Giustini C, Bui NK, Joris B, Bougault C, Vollmer W, Simorre JP. (2010) J Am Chem Soc. 132(31):10911-10909.

4. Kern T, Hediger S, Müller P, Giustini C, Joris B, Bougault C, Vollmer W, Simorre JP. (2008) J Am Chem Soc. 130(17):5618-5619.



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Understanding Surface and Interfacial Chemistry in Functional Nanomaterials via Solid-State NMR


In recent years DNP-NMR became a very important tool for ssNMR in the area of material science. This is a very nice review illustrating the application of ssNMR to the area of material science and how DNP-NMR can help to overcome sensitivity issues.


Marchetti, A., et al., Understanding Surface and Interfacial Chemistry in Functional Nanomaterials via Solid-State NMR. Adv Mater, 2017. 29(14): p. 1605895-n/a.


Surface and interfacial chemistry is of fundamental importance in functional nanomaterials applied in catalysis, energy storage and conversion, medicine, and other nanotechnologies. It has been a perpetual challenge for the scientific community to get an accurate and comprehensive picture of the structures, dynamics, and interactions at interfaces. Here, some recent examples in the major disciplines of nanomaterials are selected (e.g., nanoporous materials, battery materials, nanocrystals and quantum dots, supramolecular assemblies, drug-delivery systems, ionomers, and graphite oxides) and it is shown how interfacial chemistry can be addressed through the perspective of solid-state NMR characterization techniques.

Monday, October 16, 2017

T1 nuclear magnetic relaxation dispersion of hyperpolarized sodium and cesium hydrogencarbonate-13 C


Martinez-Santiesteban, F.M., et al., T1 nuclear magnetic relaxation dispersion of hyperpolarized sodium and cesium hydrogencarbonate-13 C. NMR Biomed, 2017. 30(9): p. e3749-n/a.


In vivo pH mapping in tissue using hyperpolarized hydrogencarbonate-13 C has been proposed as a method to study tumor growth and treatment and other pathological conditions related to pH changes. The finite spin-lattice relaxation times (T1 ) of hyperpolarized media are a significant limiting factor for in vivo imaging. Relaxation times can be measured at standard magnetic fields (1.5 T, 3.0 T etc.), but no such data are available at low fields, where T1 values can be significantly shorter. This information is required to determine the potential loss of polarization as the agent is dispensed and transported from the polarizer to the MRI scanner. The purpose of this study is to measure T1 dispersion from low to clinical magnetic fields (0.4 mT to 3.0 T) of different hyperpolarized hydrogencarbonate formulations previously proposed in the literature for in vivo pH measurements. 13 C-enriched cesium and sodium hydrogencarbonate preparations were hyperpolarized using dynamic nuclear polarization, and the T1 values of different samples were measured at different magnetic field strengths using a fast field-cycling relaxometer and a 3.0 T clinical MRI system. The effects of deuterium oxide as a dissolution medium for sodium hydrogencarbonate were also analyzed. This study finds that the cesium formulation has slightly shorter T1 values compared with the sodium preparation. However, the higher solubility of cesium hydrogencarbonate-13 C means it can be polarized at greater concentration, using less trityl radical than sodium hydrogencarbonate-13 C. This study also establishes that the preparation and handling of sodium hydrogencarbonate formulations in relation to cesium hydrogencarbonate is more difficult, due to the higher viscosity and lower achievable concentrations, and that deuterium oxide significantly increases the T1 of sodium hydrogencarbonate solutions. Finally, this work also investigates the influence of pH on the spin-lattice relaxation of cesium hydrogencarbonate-13 C measured over a pH range of 7 to 9 at 0.47 T.

Friday, October 13, 2017

Construction and 13 C hyperpolarization efficiency of a 180 GHz dissolution dynamic nuclear polarization system #DNPNMR


Kiswandhi, A., et al., Construction and 13 C hyperpolarization efficiency of a 180 GHz dissolution dynamic nuclear polarization system. Magn Reson Chem, 2017. 55(9): p. 828-836.


Dynamic nuclear polarization (DNP) via the dissolution method has become one of the rapidly emerging techniques to alleviate the low signal sensitivity in nuclear magnetic resonance (NMR) spectroscopy and imaging. In this paper, we report on the development and 13 C hyperpolarization efficiency of a homebuilt DNP system operating at 6.423 T and 1.4 K. The DNP hyperpolarizer system was assembled on a wide-bore superconducting magnet, equipped with a standard continuous-flow cryostat, and a 180 GHz microwave source with 120 mW power output and wide 4 GHz frequency tuning range. At 6.423 T and 1.4 K, solid-state 13 C polarization P levels of 64% and 31% were achieved for 3 M [1-13 C] sodium acetate samples in 1 : 1 v/v glycerol:water glassing matrix doped with 15 mM trityl OX063 and 40 mM 4-oxo-TEMPO, respectively. Upon dissolution, which takes about 15 s to complete, liquid-state 13 C NMR signal enhancements as high as 240 000-fold (P=21%) were recorded in a nearby high resolution 13 C NMR spectrometer at 1 T and 297 K. Considering the relatively lower cost of our homebuilt DNP system and the relative simplicity of its design, the dissolution DNP setup reported here could be feasibly adapted for in vitro or in vivo hyperpolarized 13 C NMR or magnetic resonance imaging at least in the pre-clinical setting. Copyright (c) 2017 John Wiley & Sons, Ltd.

Wednesday, October 11, 2017

Transportable hyperpolarized metabolites #DNPNMR


This article describes an elegant way to increase the throughput of a hyperpolarizer by storing the hyperpolarized materials separated from the polarizing agents.



Ji, X., et al., Transportable hyperpolarized metabolites. Nat Commun, 2017. 8: p. 13975.


Nuclear spin hyperpolarization of 13C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. However, because of the short lifetime of the hyperpolarized magnetization (typically <1 min), the polarization process must be carried out close to the point of use. Here we introduce a concept that markedly extends hyperpolarization lifetimes and enables the transportation of hyperpolarized metabolites. The hyperpolarized sample can thus be removed from the polarizer and stored or transported for use at remote MRI or NMR sites. We show that hyperpolarization in alanine and glycine survives 16 h storage and transport, maintaining overall polarization enhancements of up to three orders of magnitude.

[NMR] PhD/Postdoc positions available on DNP/MAS NMR and multi-frequency EPR in Konstanz, Germany #DNPNMR




PhD/Postdoc positions available on DNP/MAS NMR and multi-frequency EPR

About the group:
We are a newly established research group in the Chemistry Department of the University of Konstanz (Baden-Württemberg, Germany). Our research encompasses the development of magnetic resonance spectroscopy, particularly dynamic nuclear 
polarization (DNP) / magic-angle spinning (MAS) NMR and multi-frequency electron-paramagnetic resonance (EPR), and its application in structural biology, enzymology, and catalysis.

About the positions:
Possible research projects are: 
- To investigate if and how the high polarization generated in the photo-excited triplet states of certain chromophores can be used for DNP/MAS NMR. 
- The development of "DNP pulse sequences". This project has an experimental component as well as a considerable theoretical component. 
- The application and development of multi-frequency EPR spectroscopy to study reaction mechanisms.
The exact topic of the candidate's research can be agreed on in consultation and will depend on the candidate's background and interests.

About the candidate:
You have a strong interest in basic science, particularly in physical chemistry and spectroscopy. You are highly motivated and willing to work on solving complex, long-term problems. In your research, you are able to make the combination between theory and experiment. You have a MSc degree in Physics, Chemistry or a related field. For postdocs a PhD in MAS NMR is a plus.

About Konstanz and the university:
The University of Konstanz is a young university (founded 1966) and has since 2006 been a part of the German Exzellenzinitiative. The city of Konstanz is nicely situated on Lake Constance (Bodensee) near the Swiss border.

Applicants should send a cover letter and CV to Dr. Guinevere Mathies. E-mail: guinevere.mathies@uni-konstanz.de. Informal inquiries are also appreciated. Applications will be accepted until the positions are filled.

Visit also our website: chemie.uni.kn/mathies.


-- Dr. Guinevere Mathies Emmy Noether Group Leader Department of Chemistry University of Konstanz E-mail: guinevere.mathies@uni-konstanz.de Phone: +49 7531 88 3962 (office) Address: University of Konstanz Room L 828 / Mail box 706 Universitätsstrasse 10 78464 Konstanz Germany

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Monday, October 9, 2017

Deuteration of Hyperpolarized 13 C-Labeled Zymonic Acid Enables Sensitivity-Enhanced Dynamic MRI of pH


Hundshammer, C., et al., Deuteration of Hyperpolarized 13 C-Labeled Zymonic Acid Enables Sensitivity-Enhanced Dynamic MRI of pH. ChemPhysChem, 2017. 18(18): p. 2422-2425.


Aberrant pH is characteristic of many pathologies such as ischemia, inflammation or cancer. Therefore, a non-invasive and spatially resolved pH determination is valuable for disease diagnosis, characterization of response to treatment and the design of pH-sensitive drug-delivery systems. We recently introduced hyperpolarized [1,5-13 C2 ]zymonic acid (ZA) as a novel MRI probe of extracellular pH utilizing dissolution dynamic polarization (DNP) for a more than 10000-fold signal enhancement of the MRI signal. Here we present a strategy to enhance the sensitivity of this approach by deuteration of ZA yielding [1,5-13 C2 , 3,6,6,6-D4 ]zymonic acid (ZAd ), which prolongs the liquid state spin lattice relaxation time (T1 ) by up to 39 % in vitro. Measurements with ZA and ZAd on subcutaneous MAT B III adenocarcinoma in rats show that deuteration increases the signal-to-noise ratio (SNR) by up to 46 % in vivo. Furthermore, we demonstrate a proof of concept for real-time imaging of dynamic pH changes in vitro using ZAd , potentially allowing for the characterization of rapid acidification/basification processes in vivo.

Friday, October 6, 2017

Dynamic Nuclear Polarization Fast Field Cycling Method for the Selective Study of Molecular Dynamics in Block Copolymers #DNPNMR


Gizatullin, B., et al., Dynamic Nuclear Polarization Fast Field Cycling Method for the Selective Study of Molecular Dynamics in Block Copolymers. ChemPhysChem, 2017. 18(17): p. 2347-2356.


Dynamic nuclear polarization (DNP) is one of the most useful methods to increase sensitivity in NMR spectroscopy. It is based on the transfer of magnetization from an electron to the nuclear spin system. Based on previous work that demonstrated the feasibility of integrating DNP with fast field cycling (FFC) relaxometry and the possibility to distinguish between different mechanisms, such as the Overhauser effect (OE) and the solid effect (SE), the first FFC study of the differential relaxation properties of a copolymer is presented. For this purpose, concentrated solutions of the polystyrene-block-polybutadiene-block-polystyrene (SBS) triblock copolymer and the corresponding homopolymers were investigated. T1 -T2 relaxation data are discussed in terms of molecular mobility and the presence of radicals. The DNP selective data indicate a dominant SE contribution to the enhancement of the NMR signal for both blocks of the triblock copolymer and for the homopolymer solutions. The enhancement factors are different for both polymer types and in the copolymer, which is explained by the individual 1 H T1 relaxation times and different electron-nucleus coupling strength. The T1 relaxation dispersion measurements of the SE enhanced signal were performed, which led to improved signal-to-noise ratios that allowed the site-specific separation of relaxation times and their dependence on the Larmor frequency with a higher accuracy.

Wednesday, October 4, 2017

Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy #DNPNMR


DeHaven, B.A., et al., Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy. Chemistry, 2017. 23(34): p. 8315-8319.


UV-irradiation of a self-assembled benzophenone bis-urea macrocycle generates mum amounts of radicals that persist for weeks under ambient conditions. High-field EPR and variable-temperature X-band EPR studies suggest a resonance stabilized radical pair through H-abstraction. These endogenous radicals were applied as a polarizing agent for magic angle spinning (MAS) dynamic nuclear polarization (DNP) NMR enhancement. The field-stepped DNP enhancement profile exhibits a sharp peak with a maximum enhancement of on/off =4 superimposed on a nearly constant DNP enhancement of on/off =2 over a broad field range. This maximum coincides with the high field EPR absorption spectrum, consistent with an Overhauser effect mechanism. DNP enhancement was observed for both the host and guests, suggesting that even low levels of endogenous radicals can facilitate the study of host-guest relationships in the solid-state.

Monday, October 2, 2017

Dynamic nuclear polarization studies on deuterated nitroxyl spin probes #DNPNMR


David Jebaraj, D., H. Utsumi, and A. Milton Franklin Benial, Dynamic nuclear polarization studies on deuterated nitroxyl spin probes. Magn Reson Chem, 2017. 55(10): p. 909-916.


Detailed dynamic nuclear polarization and electron spin resonance studies were carried out for 3-carbamoyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl, 3-carboxy-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl,3-methoxycarbonyl-2,2,5,5-tetram ethy pyrolidine-1-oxyl nitroxyl radicals and their corresponding deuterated nitroxyl radicals, used in Overhauser-enhanced magnetic resonance imaging for the first time. The dynamic nuclear polarization parameters such as dynamic nuclear polarization (DNP) factor, longitudinal relaxivity, saturation parameter, leakage factor and coupling factor were estimated for deuterated nitroxyl radicals. DNP enhancement increases with agent concentration up to 3 mm and decreases above 3 mm. The proton spin-lattice relaxation time and the longitudinal relaxivity parameters were estimated. The leakage factor increases with increasing agent concentration up to 3 mm and reaches plateau in the region 3-5 mm. The coupling parameter shows the interaction between the electron and nuclear spins to be mainly dipolar in origin. DNP spectrum exhibits that the full width at half maximum values are higher for undeuterated nitroxyl radicals compared with deuterated nitroxyl radicals, which leads to the increase in DNP enhancement. The ESR parameters such as, the line width, line shape, signal intensity ratio, rotational correlation time, hyperfine coupling constant and g-factor were calculated. The narrow line width was observed for deuterated nitroxyl radicals compared with undeuterated nitroxyl radicals, which leads to the higher saturation parameter value and DNP enhancement. The novelty of the work permits clear understanding of the DNP parameters determining the higher DNP enhancement compared with the undeuterated nitroxyl radicals. Copyright (c) 2017 John Wiley & Sons, Ltd.

Friday, September 29, 2017

Pyruvate cellular uptake and enzymatic conversion probed by dissolution DNP-NMR: the impact of overexpressed membrane transporters


Balzan, R., et al., Pyruvate cellular uptake and enzymatic conversion probed by dissolution DNP-NMR: the impact of overexpressed membrane transporters. Magn Reson Chem, 2017. 55(6): p. 579-583.


Pyruvate membrane crossing and its lactate dehydrogenase-mediated conversion to lactate in cells featuring different levels of expression of membrane monocarboxylate transporters (MCT4) were probed by dissolution dynamic nuclear polarization-enhanced NMR. Hyperpolarized 13 C-1-labeled pyruvate was transferred to suspensions of rodent tumor cell carcinoma, cell line 39. The pyruvate-to-lactate conversion rate monitored by dissolution dynamic nuclear polarization-NMR in carcinoma cells featuring native MCT4 expression level was lower than the rate observed for cells in which the human MCT4 gene was overexpressed. The enzymatic activity of lactate dehydrogenase was also assessed in buffer solutions, following the real-time pyruvate-to-lactate conversion speeds at different enzyme concentrations. Copyright (c) 2016 John Wiley & Sons, Ltd.

Wednesday, September 27, 2017

Hyperpolarized 13 C magnetic resonance evaluation of renal ischemia reperfusion injury in a murine model


Baligand, C., et al., Hyperpolarized 13 C magnetic resonance evaluation of renal ischemia reperfusion injury in a murine model. NMR Biomed, 2017. 30(10): p. e3765-n/a.


Acute kidney injury (AKI) is a major risk factor for the development of chronic kidney disease (CKD). Persistent oxidative stress and mitochondrial dysfunction are implicated across diverse forms of AKI and in the transition to CKD. In this study, we applied hyperpolarized (HP) 13 C dehydroascorbate (DHA) and 13 C pyruvate magnetic resonance spectroscopy (MRS) to investigate the renal redox capacity and mitochondrial pyruvate dehydrogenase (PDH) activity, respectively, in a murine model of AKI at baseline and 7 days after unilateral ischemia reperfusion injury (IRI). Compared with the contralateral sham-operated kidneys, the kidneys subjected to IRI showed a significant decrease in the HP 13 C vitamin C/(vitamin C + DHA) ratio, consistent with a decrease in redox capacity. The kidneys subjected to IRI also showed a significant decrease in the HP 13 C bicarbonate/pyruvate ratio, consistent with impaired PDH activity. The IRI kidneys showed a significantly higher HP 13 C lactate/pyruvate ratio at day 7 compared with baseline, although the 13 C lactate/pyruvate ratio was not significantly different between the IRI and contralateral sham-operated kidneys at day 7. Arterial spin labeling magnetic resonance imaging (MRI) demonstrated significantly reduced perfusion in the IRI kidneys. Renal tissue analysis showed corresponding increased reactive oxygen species (ROS) and reduced PDH activity in the IRI kidneys. Our results show the feasibility of HP 13 C MRS for the non-invasive assessment of oxidative stress and mitochondrial PDH activity following renal IRI.

Monday, September 25, 2017

Dynamic Nuclear Polarization/Solid-State NMR Spectroscopy of Membrane Polypeptides: Free-Radical Optimization for Matrix-Free Lipid Bilayer Samples #DNPNMR


Salnikov, E.S., et al., Dynamic Nuclear Polarization/Solid-State NMR Spectroscopy of Membrane Polypeptides: Free-Radical Optimization for Matrix-Free Lipid Bilayer Samples. ChemPhysChem, 2017. 18(15): p. 2103-2113.


Dynamic nuclear polarization (DNP) boosts the sensitivity of NMR spectroscopy by orders of magnitude and makes investigations previously out of scope possible. For magic-angle-spinning (MAS) solid-state NMR spectroscopy studies, the samples are typically mixed with biradicals dissolved in a glass-forming solvent and are investigated at cryotemperatures. Herein, we present new biradical polarizing agents developed for matrix-free samples such as supported lipid bilayers, which are systems widely used for the investigation of membrane polypeptides of high biomedical importance. A series of 11 biradicals with different structures, geometries, and physicochemical properties were comprehensively tested for DNP performance in lipid bilayers, some of them developed specifically for DNP investigations of membranes. The membrane-anchored biradicals PyPol-C16, AMUPOL-cholesterol, and bTurea-C16 were found to exhibit improved g-tensor alignment, inter-radical distance, and dispersion. Consequently, these biradicals show the highest signal enhancement factors so far obtained for matrix-free membranes or other matrix-free samples and may potentially shorten NMR acquisition times by three orders of magnitude. Furthermore, the optimal biradical-to-lipid ratio, sample deuteration, and membrane lipid composition were determined under static and MAS conditions. To rationalize biradical performance better, DNP enhancement was measured by using the 13 C and 15 N signals of lipids and a peptide as a function of the biradical concentration, DNP build-up time, resonance line width, quenching effect, microwave power, and MAS frequency.

[NMR] Postdoc position on SSNMR at the University of Lille, France #DNPNMR

Fromt the Ampere Magnetic Resonance List



Please forward to potential candidates.

Project title: Development of high-field (DNP)-NMR methods to detect quadrupolar nuclei on catalytic surfaces

A two-year postdoc position in solid-state NMR spectroscopy of advanced materials is available at the University of Lille, Lille, France. It will start preferably in December 2017.

Project description: The development of improved heterogeneous catalysts can be undertaken in a rational way by a better
understanding of their structures. Solid-state NMR spectroscopy is very well suited to the study of heterogeneous catalysts because it can give information on the local structure. However, the lack of sensitivity and resolution poses limit for the characterization of surface sites, notably when they are occupied by quadrupolar nuclei (11B, 17O, 27Al, 67Zn, 95Mo...) exhibiting NMR signal broaden by large quadrupolar interaction. This project aims at developing and applying novel solid-state high-field (DNP)NMR methods to probe the local environment of quadrupolar nuclei. It will provide unique insights into the structure of the catalytic surfaces, which will be useful to improve their performances.

Host and research infrastructure: Lille is a vibrant and handsome city, imbued with a rich history, located in the center of northwestern Europe (only 30 min by high-speed trains from Brussels, 1h from Paris and 1h30 from London). Lille is one of France’s top student cities and the university of Lille is a leading center for magnetic resonance. Lille NMR facility includes 800 and 900 MHz NMR spectrometers and has been selected to host the first 1.2 GHz NMR spectrometer to be installed in France. Our research group is internationally known for the development of solid-state NMR methods, notably for quadrupolar nuclei, and the characterization of heterogeneous catalysts. We have an expertise in high-field solid-state NMR spectroscopy and were among the pioneers of high-field DNP-NMR of hybrid and inorganic materials. 

The person: We seek application from candidates with experience in the development of solid-state NMR methods and/or the NMR characterization of inorganic materials and catalysts. The successful applicant will be given the opportunity to work in an exciting environment with national and international collaborations.

Contact: Applications and informal queries about the lab and research projects should be directed by


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Friday, September 22, 2017

Nanodiamond-enhanced MRI via in situ hyperpolarization


Waddington, D.E.J., et al., Nanodiamond-enhanced MRI via in situ hyperpolarization. Nat Commun, 2017. 8: p. 15118.


Nanodiamonds are of interest as nontoxic substrates for targeted drug delivery and as highly biostable fluorescent markers for cellular tracking. Beyond optical techniques, however, options for noninvasive imaging of nanodiamonds in vivo are severely limited. Here, we demonstrate that the Overhauser effect, a proton-electron polarization transfer technique, can enable high-contrast magnetic resonance imaging (MRI) of nanodiamonds in water at room temperature and ultra-low magnetic field. The technique transfers spin polarization from paramagnetic impurities at nanodiamond surfaces to 1H spins in the surrounding water solution, creating MRI contrast on-demand. We examine the conditions required for maximum enhancement as well as the ultimate sensitivity of the technique. The ability to perform continuous in situ hyperpolarization via the Overhauser mechanism, in combination with the excellent in vivo stability of nanodiamond, raises the possibility of performing noninvasive in vivo tracking of nanodiamond over indefinitely long periods of time.

Wednesday, September 20, 2017

Measuring Nano- to Microstructures from Relayed Dynamic Nuclear Polarization NMR #DNPNMR


Pinon, A.C., et al., Measuring Nano- to Microstructures from Relayed Dynamic Nuclear Polarization NMR. The Journal of Physical Chemistry C, 2017. 121(29): p. 15993-16005.


We show how dynamic nuclear polarization (DNP) NMR can be used in combination with models for polarization dynamics to determine the domain sizes in complex materials. By selectively doping a source component with radicals and leaving the target undoped, we can measure experimental polarization buildup curves which can be compared with simulations based on heterogeneous distributions of polarization within the sample. The variation of the integrated DNP enhancement as a function of the polarization time is found to be characteristic of the geometry. We demonstrate the method experimentally on four different systems where we successfully determine domain sizes between 200 and 20 000 nm, specifically in powdered histidine hydrochloride monohydrate, pore lengths of mesoporous silica materials, and two domain sizes in two-component polymer film coatings. Additionally, we find that even in the apparently homogeneous frozen solutions used as polarization sources in most DNP experiments, polarization is relayed from protons near the radicals to the bulk of the solution by spin diffusion, which explains the experimentally observed buildup times in these samples.

Monday, September 18, 2017

Unprecedented Carbon Signal Enhancement in Liquid-State NMR Spectroscopy #DNPNMR


Pinter, G. and H. Schwalbe, Unprecedented Carbon Signal Enhancement in Liquid-State NMR Spectroscopy. Angew Chem Int Ed Engl, 2017. 56(29): p. 8332-8334.


We shall overcome: As a result of efforts to overcome the sensitivity challenge of liquid-state NMR spectroscopy, a thousand-fold signal enhancement was achieved by dynamic nuclear polarization (DNP) for 13 C signals at high magnetic field (3.4 T) and room temperature, thereby exceeding the predicted limitations of high-field liquid-state in situ DNP.

Friday, September 15, 2017


Barskiy, D.A., et al., NMR Hyperpolarization Techniques of Gases. Chemistry, 2017. 23(4): p. 725-751.


Nuclear spin polarization can be significantly increased through the process of hyperpolarization, leading to an increase in the sensitivity of nuclear magnetic resonance (NMR) experiments by 4-8 orders of magnitude. Hyperpolarized gases, unlike liquids and solids, can often be readily separated and purified from the compounds used to mediate the hyperpolarization processes. These pure hyperpolarized gases enabled many novel MRI applications including the visualization of void spaces, imaging of lung function, and remote detection. Additionally, hyperpolarized gases can be dissolved in liquids and can be used as sensitive molecular probes and reporters. This Minireview covers the fundamentals of the preparation of hyperpolarized gases and focuses on selected applications of interest to biomedicine and materials science.

Thursday, September 14, 2017

[NMR] Nobel Prize winner Nico Bloembergen passed away at age 97


From the Ampere Magnetic Resonance List:

Dear colleagues,

Last week, Nobel laureate Professor Nicolaas Bloembergen, a pioneer in the field of NMR and laser spectroscopy passed away at age of 97. As an undergraduate Bloembergen studied Physics at Utrecht University from 1938 to 1943 and received his PhD in Physics from Leiden University with C.J. Gorter in 1948 on the topic of Nuclear Magnetic Relaxation. His thesis resulted in the famous BPP (Bloembergen, Purcell and Pound) paper which still serves as a point of departure for understanding many NMR relaxation experiments. In 1973 he returned to Leiden and occupied the Lorentz Chair in Physics. In 1981, he was awarded the Nobel Prize in Physics for his work in coherent optics. In 2001 in honour of his achievements, the NMR group at Utrecht University named their laboratory the Bloembergen Building.

For further information on a true scientific giant, please look out for an obituary written by C. Luchinat, R. Boelens, and R. Kaptein that will appear on the Ampere website and in the Ampere newsletter soon.

Also, please see, for example:

Best wishes,
Marc Baldus



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Wednesday, September 13, 2017

Single-scan 13C diffusion-ordered NMR spectroscopy of DNP-hyperpolarised substrates #DNPNMR


Guduff, L., et al., Single-scan 13C diffusion-ordered NMR spectroscopy of DNP-hyperpolarised substrates. Chemistry, 2017: p. n/a-n/a.


Diffusion-ordered NMR spectroscopy (DOSY) is a powerful approach for the analysis of molecular mixtures, yet its application range is limited by the relatively low sensitivity of NMR. We show here that spectrally resolved 13C DOSY data can be collected, in a single scan, for substrates hyperpolarised by dissolution dynamic nuclear polarisation (D-DNP), which provides signal enhancements of several orders of magnitude. For this we use a convection-compensation pulse scheme, which we also analyse by numerical simulation. The proposed method further allows the acquisition of several consecutive DOSY spectra in a single D-DNP experiment.

Monday, September 11, 2017

Overhauser-enhanced magnetic resonance elastography


Salameh, N., et al., Overhauser-enhanced magnetic resonance elastography. NMR in Biomedicine, 2016. 29(5): p. 607-613.


Magnetic resonance elastography (MRE) is a powerful technique to assess the mechanical properties of living tissue. However, it suffers from reduced sensitivity in regions with short T2 and T2* such as in tissue with high concentrations of paramagnetic iron, or in regions surrounding implanted devices. In this work, we exploit the longer T2* attainable at ultra-low magnetic fields in combination with Overhauser dynamic nuclear polarization (DNP) to enable rapid MRE at 0.0065 T. A 3D balanced steady-state free precession based MRE sequence with undersampling and fractional encoding was implemented on a 0.0065 T MRI scanner. A custom-built RF coil for DNP and a programmable vibration system for elastography were developed. Displacement fields and stiffness maps were reconstructed from data recorded in a polyvinyl alcohol gel phantom loaded with stable nitroxide radicals. A DNP enhancement of 25 was achieved during the MRE sequence, allowing the acquisition of 3D Overhauser-enhanced MRE (OMRE) images with (1.5 × 2.7 × 9) mm3 resolution over eight temporal steps and 11 slices in 6 minutes. In conclusion, OMRE at ultra-low magnetic field can be used to detect mechanical waves over short acquisition times. This new modality shows promise to broaden the scope of conventional MRE applications, and may extend the utility of low-cost, portable MRI systems to detect elasticity changes in patients with implanted devices or iron overload. Copyright © 2016 John Wiley & Sons, Ltd.