Wednesday, December 24, 2014

Blogging Break

Hi everyone, I will take a break blogging over the the holiday season. The next blog post will be published January 5th.

Hope you all enjoy the Holiday Season.
Cheers, Thorsten


Friday, December 19, 2014

Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR


Buratto, R., et al., Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR. ChemMedChem, 2014. 9(11): p. 2509-2515.


Transverse and longitudinal relaxation times (T1ρ and T1) have been widely exploited in NMR to probe the binding of ligands and putative drugs to target proteins. We have shown recently that long-lived states (LLS) can be more sensitive to ligand binding. LLS can be excited if the ligand comprises at least two coupled spins. Herein we broaden the scope of ligand screening by LLS to arbitrary ligands by covalent attachment of a functional group, which comprises a pair of coupled protons that are isolated from neighboring magnetic nuclei. The resulting functionalized ligands have longitudinal relaxation times T1(1H) that are sufficiently long to allow the powerful combination of LLS with dissolution dynamic nuclear polarization (D-DNP). Hyperpolarized weak “spy ligands” can be displaced by high-affinity competitors. Hyperpolarized LLS allow one to decrease both protein and ligand concentrations to micromolar levels and to significantly increase sample throughput.

Wednesday, December 17, 2014

Long-Lived States of Magnetically Equivalent Spins Populated by Dissolution-DNP and Revealed by Enzymatic Reactions


Bornet, A., et al., Long-Lived States of Magnetically Equivalent Spins Populated by Dissolution-DNP and Revealed by Enzymatic Reactions. Chemistry, 2014. 20(51): p. 17113-8.


Hyperpolarization by dissolution dynamic nuclear polarization (D-DNP) offers a way of enhancing NMR signals by up to five orders of magnitude in metabolites and other small molecules. Nevertheless, the lifetime of hyperpolarization is inexorably limited, as it decays toward thermal equilibrium with the nuclear spin-lattice relaxation time. This lifetime can be extended by storing the hyperpolarization in the form of long-lived states (LLS) that are immune to most dominant relaxation mechanisms. Levitt and co-workers have shown how LLS can be prepared for a pair of inequivalent spins by D-DNP. Here, we demonstrate that this approach can also be applied to magnetically equivalent pairs of spins such as the two protons of fumarate, which can have very long LLS lifetimes. As in the case of para-hydrogen, these hyperpolarized equivalent LLS (HELLS) are not magnetically active. However, a chemical reaction such as the enzymatic conversion of fumarate into malate can break the magnetic equivalence and reveal intense NMR signals.

5th International DNP Symposium

I'm very excited to see that the 5th International DNP Symposium will be held from August 31st to September 4th, 2015 in Egmond aan Zee, The Netherlands.

The following speakers have confirmed to give a plenary lecture:

Jan Henrik Ardenkjaer-Larsen (Technical University of Denmark)
Geoffrey Bodenhausen (EPFL Lausanne & ENS Paris)
Kevin Brindle (University of Cambridge)
Robert G. Griffin (MIT)
Olivier Lafon (University of Lille)
Songi Han (UC Santa Barbara)
Malcolm Levitt (University of Southampton)
Robert Kaptein (Utrecht University)

Registration will be opening in early 2015. For more information please visit: http://www.nmr-nl.org/hyperpolarizedMR

Monday, December 15, 2014

In Situ and Ex Situ Low-Field NMR Spectroscopy and MRI Endowed by SABRE Hyperpolarization


Barskiy, D.A., et al., In Situ and Ex Situ Low-Field NMR Spectroscopy and MRI Endowed by SABRE Hyperpolarization. ChemPhysChem, 2014. 15(18): p. 4100-7.


By using 5.75 and 47.5 mT nuclear magnetic resonance (NMR) spectroscopy, up to 10(5) -fold sensitivity enhancement through signal amplification by reversible exchange (SABRE) was enabled, and subsecond temporal resolution was used to monitor an exchange reaction that resulted in the buildup and decay of hyperpolarized species after parahydrogen bubbling. We demonstrated the high-resolution low-field proton magnetic resonance imaging (MRI) of pyridine in a 47.5 mT magnetic field endowed by SABRE. Molecular imaging (i.e. imaging of dilute hyperpolarized substances rather than the bulk medium) was conducted in two regimes: in situ real-time MRI of the reaction mixture (in which pyridine was hyperpolarized), and ex situ MRI (in which hyperpolarization decays) of the liquid hyperpolarized product. Low-field (milli-Tesla range, e.g. 5.75 and 47.5 mT used in this study) parahydrogen-enhanced NMR and MRI, which are free from the limitations of high-field magnetic resonance (including susceptibility-induced gradients of the static magnetic field at phase interfaces), potentially enables new imaging applications as well as differentiation of hyperpolarized chemical species on demand by exploiting spin manipulations with static and alternating magnetic fields.

Friday, December 12, 2014

Hyperpolarized cesium ions doped in a glass material


Ishikawa, K., Hyperpolarized cesium ions doped in a glass material. J Magn Reson, 2014. 249C(0): p. 94-99.


Hyperpolarized (HP) 133Cs nuclear magnetic resonance signals were measured from borosilicate glass cell walls during optical pumping of cesium vapor at high magnetic field (9.4T). Significant signal enhancements were observed when additional heating of the cell wall was provided by intense but non-resonant laser irradiation, with integrated HP 133Cs NMR signals and line widths varying as a function of heating laser power (and hence glass temperature). Given that virtually no Cs ions would originally be present in the glass, absorbed HP Cs atoms rarely met thermally-polarized Cs ions already at the surface; thus, spin-exchange via nuclear dipole interaction cannot be the primary mechanism for injecting spin polarization into the glass. Instead, it is concluded that the absorption and transport of HP atoms into the glass material itself is the dominant mechanism of nuclear spin injection at high temperatures-the first reported experimental demonstration of such a mechanism.

Wednesday, December 10, 2014

Dipolar induced Para-Hydrogen-Induced Polarization


Buntkowsky, G., et al., Dipolar induced Para-Hydrogen-Induced Polarization. Solid State Nucl Magn Reson, 2014. 63-64(0): p. 20-9.


Analytical expressions for the signal enhancement in solid-state PHIP NMR spectroscopy mediated by homonuclear dipolar interactions and single pulse or spin-echo excitation are developed and simulated numerically. It is shown that an efficient enhancement of the proton NMR signal in solid-state NMR studies of chemisorbed hydrogen on surfaces is possible. Employing typical reaction efficacy, enhancement-factors of ca. 30-40 can be expected both under ALTADENA and under PASADENA conditions. This result has important consequences for the practical application of the method, since it potentially allows the design of an in-situ flow setup, where the para-hydrogen is adsorbed and desorbed from catalyst surfaces inside the NMR magnet.

Monday, December 8, 2014

Postdoc position available in Solid-State NMR at Stockholm University

From the Ampere Magnetic Resonance List


Postdoctoral Researcher Position in Solid-State NMR at Stockholm University

at the Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Sweden

The Department of Materials and Environmental Chemistry (MMK) at Stockholm University is internationally renowned for developing and characterizing properties and structures of modern materials, where solid-state NMR represents one of the characterization techniques. The solid-state NMR instrumentation at MMK includes two wide-bore magnets (9.4 T and 14.1 T) with triple-channel Bruker Avance-III spectrometers and a multitude of MAS probeheads. The solid-state NMR research at MMK is focused on developing and applying solid-state NMR spectroscopy techniques for structural investigations of structurally disordered inorganic materials, in particular glasses and porous materials.

Project Description
We are inviting a self-motivated and creative individual to apply for one postdoctoral opening that involves developing new MAS NMR methodology for determining internuclear distances among spins-1/2 as well as among half-integer spins within multi-spin networks. The techniques will be applied to structurally disordered materials, such as aluminosilicate glasses, bioactive silicate glasses, and bone. The successful candidate will be collaborating with researchers responsible for computer modeling (e.g., MD simulations) and other structural characterization techniques.
Examples of recent publications relevant to the project:
[1] Low-Power Broadband Homonuclear Dipolar Recoupling without Decoupling: Double-Quantum 13C NMR Correlations at Very Fast Magic-Angle Spinning, G. Teymoori, B. Pahari, B. Stevensson and M. Edén, Chem. Phys., Lett., 547, 103-109 (2012)

[2] Multiple-Quantum Spin Counting in Magic-Angle Spinning NMR via Low-Power Symmetry-Based Dipolar Recoupling, G. Teymoori, B. Pahari, E. Viswanathan and M. Edén, J. Magn. Reson, 236, 31-40 (2013)

[3] Central-Transition Double-Quantum Sideband NMR Spectroscopy of Half-Integer Quadrupolar Nuclei: Estimating Internuclear Distances and Probing Clusters within Multi-Spin Network, A. Brinkmann and M. Edén, Phys. Chem. Chem. Phys, 16, 7037-7050 (2014)

Eligibility & Selection Criteria
The applicant should have a PhD degree in Chemistry or Physics (or equivalent thereof) and significant experience in MAS NMR experimentation. The selection is based primarily on scientific excellence in the field of MAS NMR: previous experience with developing and utilizing advanced solid-state NMR techniques, and/or NMR theory development is required and should be documented in the application. Previous experience with Bruker Avance spectrometers and/or experience with NMR on quadrupolar nuclei are considered advantageous. Skills in computer programming will be beneficial, but not necessary. Please do not apply if you lack experience with solid-state NMR.

Conditions of employment
The position involves a full time employment for 12 months, with the possibility of further extension up to 24 months. The financial support is through a stipend (free of tax) of 20 000 SEK/month. The position is to be filled the soonest possible, with an intended starting date from February 2015 (the precise date is negotiable). Reviewing of the applications will begin immediately and proceed until the position is filled.

Additional Information
Further information about the Department of Materials and Environmental Chemistry may be found at http://www.mmk.su.se/.

Further info about the PI: http://www.mmk.su.se/page.php?pid=155&id=220

For inquiries, please contact Professor Mattias Edén: mattias.eden@mmk.su.se

Application

The application should be written in English and must include
  • Letter of interest with a description of research interests and previous experience with solid-state NMR, relevant for the present position.
  • CV and publication list
  • copies of diploma of scientific degrees and transcripts of academic records
  • the contact information of at least two references
Please send your application by email as a single pdf file to: mattias.eden@mmk.su.se, with the reference “SU-POSTDOC NMR” in the subject line. Reviewing of the applications will begin immediately and proceed until the position is filled.

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Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging


This is a very nice review of cavities that are used in EPR, NMR and MRI. So far resonators have not been widely employed in DNP spectroscopy - only in some static DNP experiments. However, it is an intriguing problem that could, if solved, allow using cost-effective solid-state sources for DNP even at high temperatures.
Even if this article is not specifically about resonators for DNP it gives a very nice overview of the concepts that drive resonator design for magnetic resonance applications.



Webb, A., Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging. Prog Nucl Magn Reson Spectrosc, 2014. 83C: p. 1-20.


Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

Friday, December 5, 2014

Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations


Gerlovin, I.Y., et al., Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations. AIP Conference Proceedings, 2013. 1566(1): p. 319-320.


The degree of circular polarization of photoluminescence of (In,Ga)As quantum dots as a function of magnetic field applied perpendicular to the optical axis (Hanle effect) is experimentally studied. The measurements have been performed at various regimes of the optical excitation modulation. The analysis of experimental data has been performed in the framework of a vector model of regular nuclear spin polarization and its fluctuations. The analysis allowed us to evaluate the magnitude of nuclear polarization and its dynamics at the experimental conditions used.

Wednesday, December 3, 2014

L-band Overhauser dynamic nuclear polarization

I must have missed that article from 2010, describing L-Band ODNP experiments. This actually looks like a very nice setup that could be used for teaching purposes.


Garcia, S., et al., L-band Overhauser dynamic nuclear polarization. J Magn Reson, 2010. 203(1): p. 138-43.


We present the development of an Overhauser dynamic nuclear polarization (DNP) instrument at 0.04 T using 1.1 GHz (L-band) electron spin resonance frequencies (ESR) and 1.7 MHz (1)H nuclear magnetic resonance frequencies. Using this home-built DNP system, the electron-nucleus coupling factor of 4-oxo-TEMPO dissolved in water was determined as 0.39+/-0.06 at 0.04 T. The higher coupling factor obtained at this field compared to higher magnetic fields, such as 0.35 T, directly translates to higher enhancement of the NMR signal and opens up a wider time scale window for observing water dynamics interacting with macromolecular systems, including proteins, polymers or lipid vesicles. The higher enhancements obtained will facilitate the observation of water dynamics at correlation times up to 10 ns, that corresponds to more than one order of magnitude slower dynamics than accessible at 0.35 T using X-band ESR frequencies.

Monday, November 24, 2014

[NMR] Postdoctoral position in Hyperpolarized Magnetic Resonance at the MR-Centre, Aarhus University Hospital, Denmark

From the Ampere Magnetic Resonance List

Background for the position

The current one year position (with possibility of prolongation) is available through a grant for the LIFE-DNP program obtained from The Danish Council for Strategic Research to the MR Research Centre, Aarhus University and its partners. 


Read more about the MR Research Centre and the program at mr.au.dk

We offer: 

An interdisciplinary and dynamic environment within an international research group. An excellent laboratory infrastructure with state-of-the-art equipment, including one SPINlab polarizer system linked to a 3T clinical scanner and a 9.4T pre-clinical scanner. Additionally, laboratory for cell culture studies, animal based studies and other facilities for patient and clinical scanners are available. 

Project description: 

Hyperpolarized MR is a new technology enhancing MR spectroscopy and imaging for metabolic studies with until now unseen sensitivity. The overall aim of the present research program is to explore metabolic mechanisms that link dietary patterns and lifestyle with diseases included in the metabolic syndrome complex like diabetes, obesity, cancer or heart diseases. The research is based on cells (bio-reactors), animals (rodents and pigs) and further translation to human studies will be initiated soon. 

The holder of the announced Post Doc position is expected to formulate own research based on the hyperpolarization technique. 

Furthermore the researcher should: 

• introduce new bio-probes (spin physics, chemistry etc.) for experimental studies of the metabolic complex diseases; 
• develop novel methods for MR data acquisitions and analysis; 
• interpretation of MR-hyperpolarization data for quantification of metabolic flux patterns relevant for the above general aims and translate these into a clinical perspective. 

Selection criteria 

• The candidate must hold a PhD or equivalent degree in areas linking natural sciences and life sciences. 
• The candidate must demonstrate strong competences in physics, chemistry, data processing, MR-spectroscopy and its application in life-sciences. 
• Prior practical experience with the MR-hyperpolarization technique will be appreciated. 
• Convincing knowledge in proper experimental planning, power calculations, and statistical evaluation of experimental data. 
• An analytical attitude of devising innovative scientific or technical solutions. 
• Excellent scientific track record 
• Excellent English communication skills, both written and verbal 
• An enthusiastic, dedicated and collaborative attitude to the project is prerequisite. 

Relationships 
• The candidate will be employed at the MR Research Centre, Department of Clinical Medicine. The holder of the position will primarily report to the principle investigator Prof. Hans Stødkilde-Jørgensen. 
• The holder of the position is expected to interact with staff at all levels, both internally and externally, regarding relevant research topics. 
• Highly motivated and ambitious candidates are encouraged to apply. Solid experience and an excellent track record gained in leading laboratories in the research field will be considered a distinct advantage. In all cases, ability to perform the job will be the primary consideration, and thus we encourage all – regardless of their personal background and status – to apply. 

Questions 
Further information can be requested from prof. Hans Stødkilde-Jørgensen (+45 7845 6113), assistant prof. Christoffer Laustsen (+45 7846 6139) or associate prof. Steffen Ringgaard (+45 7845 6123). 

For more information on working at Aarhus University and living in Denmark: http://ias.au.dk/international-academic-staff-ias/

Aarhus University is an academically diverse and strongly research-oriented institution that creates and shares knowledge. The university was founded in 1928 and today it has several world class research fields. Aarhus University (AU) is a top ten university among universities founded within the past 100 years. It has a long tradition of partnerships with some of the world's best research institutions and university networks. Please read more about Aarhus University at http://www.au.dk/en/about/profile

Application formalities 
The application must be in English and include a curriculum vitae, degree certificate, a complete list of publications, a statement of future research plans and information about research activities, teaching portfolio and verified information on previous teaching experience (if any).

Application deadline: 
All applications must be made online and received by: 17.12.2014 

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C&EN: Agilent Draws Academics’ Ire

C&EN, the magazine of the American Chemical Society had an interesting article about Agilent leaving the NMR business, that you can find here:


Also, if you wanna read the open letter of the NMR community to Agilent, you can find it here:

Direct Evidence of Imino Acid–Aromatic Interactions in Native Collagen Protein by DNP-Enhanced Solid-State NMR Spectroscopy


Singh, C., et al., Direct Evidence of Imino Acid–Aromatic Interactions in Native Collagen Protein by DNP-Enhanced Solid-State NMR Spectroscopy. The Journal of Physical Chemistry Letters, 2014. 5(22): p. 4044-4048.


Aromatic amino acids (AAAs) have rare presence (?1.4% abundance of Phe) inside of collagen protein, which is the most abundant animal protein playing a functional role in skin, bone, and connective tissues. The role of AAAs is very crucial and has been debated. We present here experimental results depicting interaction of AAAs with imino acids in a native collagen protein sample. The interaction is probed by solid-state NMR (ssNMR) spectroscopy experiments such as 1H?13C heteronuclear correlation (HETCOR) performed on a native collagen sample. The natural abundance 13C spectrum was obtained by dynamic nuclear polarization (DNP) sensitivity enhancement coupled with ssNMR, providing 30-fold signal enhancement. Our results also open up new avenues of probing collagen structure/dynamics closest to the native state by ssNMR experiments coupled with DNP.

Friday, November 21, 2014

Unraveling the core-shell structure of ligand-capped Sn/SnOx nanoparticles by surface-enhanced nuclear magnetic resonance, Mossbauer, and X-ray absorption spectroscopies


Protesescu, L., et al., Unraveling the core-shell structure of ligand-capped Sn/SnOx nanoparticles by surface-enhanced nuclear magnetic resonance, Mossbauer, and X-ray absorption spectroscopies. ACS Nano, 2014. 8(3): p. 2639-48.


A particularly difficult challenge in the chemistry of nanomaterials is the detailed structural and chemical analysis of multicomponent nano-objects. This is especially true for the determination of spatially resolved information. In this study, we demonstrate that dynamic nuclear polarization surface-enhanced solid-state NMR spectroscopy (DNP-SENS), which provides selective and enhanced NMR signal collection from the (near) surface regions of a sample, can be used to resolve the core-shell structure of a nanoparticle. Li-ion anode materials, monodisperse 10-20 nm large tin nanoparticles covered with a approximately 3 nm thick layer of native oxides, were used in this case study. DNP-SENS selectively enhanced the weak 119Sn NMR signal of the amorphous surface SnO2 layer. Mossbauer and X-ray absorption spectroscopies identified a subsurface SnO phase and quantified the atomic fractions of both oxides. Finally, temperature-dependent X-ray diffraction measurements were used to probe the metallic beta-Sn core and indicated that even after 8 months of storage at 255 K there are no signs of conversion of the metallic beta-Sn core into a brittle semiconducting alpha-phase, a phase transition which normally occurs in bulk tin at 286 K (13 degrees C). Taken together, these results indicate that Sn/SnOx nanoparticles have core/shell1/shell2 structure of Sn/SnO/SnO2 phases. The study suggests that DNP-SENS experiments can be carried on many types of uniform colloidal nanomaterials containing NMR-active nuclei, in the presence of either hydrophilic (ion-capped surfaces) or hydrophobic (capping ligands with long hydrocarbon chains) surface functionalities.

Wednesday, November 19, 2014

NMR-based structural biology enhanced by dynamic nuclear polarization at high magnetic field


Koers, E.J., et al., NMR-based structural biology enhanced by dynamic nuclear polarization at high magnetic field. J Biomol NMR, 2014. 60(2-3): p. 157-68.


Dynamic nuclear polarization (DNP) has become a powerful method to enhance spectroscopic sensitivity in the context of magnetic resonance imaging and nuclear magnetic resonance spectroscopy. We show that, compared to DNP at lower field (400 MHz/263 GHz), high field DNP (800 MHz/527 GHz) can significantly enhance spectral resolution and allows exploitation of the paramagnetic relaxation properties of DNP polarizing agents as direct structural probes under magic angle spinning conditions. Applied to a membrane-embedded K(+) channel, this approach allowed us to refine the membrane-embedded channel structure and revealed conformational substates that are present during two different stages of the channel gating cycle. High-field DNP thus offers atomic insight into the role of molecular plasticity during the course of biomolecular function in a complex cellular environment.

Monday, November 17, 2014

Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations


Gerlovin, I.Y., et al., Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations. AIP Conference Proceedings, 2013. 1566(1): p. 319-320.


The degree of circular polarization of photoluminescence of (In,Ga)As quantum dots as a function of magnetic field applied perpendicular to the optical axis (Hanle effect) is experimentally studied. The measurements have been performed at various regimes of the optical excitation modulation. The analysis of experimental data has been performed in the framework of a vector model of regular nuclear spin polarization and its fluctuations. The analysis allowed us to evaluate the magnitude of nuclear polarization and its dynamics at the experimental conditions used.

Friday, November 14, 2014

The electron depolarization during dynamic nuclear polarization: measurements and simulations


Hovav, Y., et al., The electron depolarization during dynamic nuclear polarization: measurements and simulations. Phys. Chem. Chem. Phys., 2014.


Dynamic nuclear polarization is typically explained either using microscopic systems, such as in the solid effect and cross effect mechanisms, or using the macroscopic formalism of spin temperature which assumes that the state of the electrons can be described using temperature coefficients, giving rise to the thermal mixing mechanism. The distinction between these mechanisms is typically made by measuring the DNP spectrum - i.e. the nuclear enhancement profile as a function of irradiation frequency. In particular, we have previously used the solid effect and cross effect mechanisms to explain temperature dependent DNP spectra. Our past analysis has however neglected the effect of depolarization of the electrons resulting from the microwave (MW) irradiation. In this work we concentrate on this electron depolarization process and perform electron-electron double resonance (ELDOR) experiments on TEMPOL and trityl frozen solutions, using a 3.34 Tesla magnet and at 2.7-30 K, in order to measure the state of the electron polarization during DNP. The experiments indicate that a significant part of the EPR line is affected by the irradiation due to spectral diffusion. Using a theoretical framework based on rate equations for the polarizations of the different electron spin packets and for those of the nuclei we simulated the various ELDOR line-shapes and reproduced the MW frequency and irradiation time dependence. The obtained electron polarization distribution cannot be described using temperature coefficients as required by the classical thermal mixing mechanism, and therefore the DNP mechanism cannot be described by thermal mixing. Instead, the theoretical framework presented here for the analysis of the ELDOR data forms a basis for future interpretation of DNP spectra in combination with EPR measurements.

Wednesday, November 12, 2014

DNP visiting scientist positio at NHMFL

From the Ampere Magnetic Resonance List

A visiting scientist position is available at the U.S. National High Magnetic Field Laboratory (NHMFL) in Tallahassee Florida as part of a major initiative on Dynamic Nuclear Polarization (DNP) including magic-angle spinning (MAS) DNP, dissolution DNP and Overhauser solution DNP. The position will be focused primarily on but not limited to MAS DNP. A Bruker 600MHz DNP system has recently been installed and a 600MHz field-sweepable wide-bore magnet will be delivered soon to the NHMFL. The visiting scientist is expected to develop independent and collaborative research in chemical, biological and material applications of DNP as well as DNP instrumentation and technology. The scientist 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. 

Minimum qualifications include a Ph.D. in Chemistry, Physics, Biology or a related discipline. Experience in DNP is expected. To apply, please send a CV, a cover letter describing your experience and research interests, and contact information for three references to 

Zhehong Gan 
National High Magnetic Field Laboratory 
1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA 

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Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization


Gajan, D., et al., Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization. Proc. Nat. Aca. Sci. USA, 2014. 111(41): p. 14693-14697.


Hyperpolarization of substrates for magnetic resonance spectroscopy (MRS) and imaging (MRI) by dissolution dynamic nuclear polarization (D-DNP) usually involves saturating the ESR transitions of polarizing agents (PAs; e.g., persistent radicals embedded in frozen glassy matrices). This approach has shown enormous potential to achieve greatly enhanced nuclear spin polarization, but the presence of PAs and/or glassing agents in the sample after dissolution can raise concerns for in vivo MRI applications, such as perturbing molecular interactions, and may induce the erosion of hyperpolarization in spectroscopy and MRI. We show that D-DNP can be performed efficiently with hybrid polarizing solids (HYPSOs) with 2,2,6,6-tetramethyl-piperidine-1-oxyl radicals incorporated in a mesostructured silica material and homogeneously distributed along its pore channels. The powder is wetted with a solution containing molecules of interest (for example, metabolites for MRS or MRI) to fill the pore channels (incipient wetness impregnation), and DNP is performed at low temperatures in a very efficient manner. This approach allows high polarization without the need for glass-forming agents and is applicable to a broad range of substrates, including peptides and metabolites. During dissolution, HYPSO is physically retained by simple filtration in the cryostat of the DNP polarizer, and a pure hyperpolarized solution is collected within a few seconds. The resulting solution contains the pure substrate, is free from any paramagnetic or other pollutants, and is ready for in vivo infusion.

Monday, November 10, 2014

Amplifying dynamic nuclear polarization of frozen solutions by incorporating dielectric particles


Kubicki, D.J., et al., Amplifying dynamic nuclear polarization of frozen solutions by incorporating dielectric particles. J Am Chem Soc, 2014. 136(44): p. 15711-8.


There is currently great interest in understanding the limits on NMR signal enhancements provided by dynamic nuclear polarization (DNP), and in particular if the theoretical maximum enhancements can be achieved. We show that over a 2-fold improvement in cross-effect DNP enhancements can be achieved in MAS experiments on frozen solutions by simply incorporating solid particles into the sample. At 9.4 T and approximately 105 K, enhancements up to epsilonH = 515 are obtained in this way, corresponding to 78% of the theoretical maximum. We also underline that degassing of the sample is important to achieve highest enhancements. We link the amplification effect to the dielectric properties of the solid material, which probably gives rise to scattering, diffraction, and amplification of the microwave field in the sample. This is substantiated by simulations of microwave propagation. A reduction in sample heating at a given microwave power also likely occurs due to reduced dielectric loss. Simulations indicate that the microwave field (and thus the DNP enhancement) is inhomogeneous in the sample, and we deduce that in these experiments between 5 and 10% of the solution actually yields the theoretical maximum signal enhancement of 658. The effect is demonstrated for a variety of particles added to both aqueous and organic biradical solutions.

Friday, November 7, 2014

LIGHT-SABRE enables efficient in-magnet catalytic hyperpolarization


Theis, T., et al., LIGHT-SABRE enables efficient in-magnet catalytic hyperpolarization. J Magn Reson, 2014. 248C(0): p. 23-26.


Nuclear spin hyperpolarization overcomes the sensitivity limitations of traditional NMR and MRI, but the most general method demonstrated to date (dynamic nuclear polarization) has significant limitations in scalability, cost, and complex apparatus design. As an alternative, signal amplification by reversible exchange (SABRE) of parahydrogen on transition metal catalysts can hyperpolarize a variety of substrates, but to date this scheme has required transfer of the sample to low magnetic field or very strong RF irradiation. Here we demonstrate "Low-Irradiation Generation of High Tesla-SABRE" (LIGHT-SABRE) which works with simple pulse sequences and low power deposition; it should be usable at any magnetic field and for hyperpolarization of many different nuclei. This approach could drastically reduce the cost and complexity of producing hyperpolarized molecules.

Wednesday, November 5, 2014

Cross polarization from (1)H to quadrupolar (6)Li nuclei for dissolution DNP


Perez Linde, A.J., et al., Cross polarization from (1)H to quadrupolar (6)Li nuclei for dissolution DNP. Phys Chem Chem Phys, 2014. 16(45): p. 24813-7.


Cross polarization from protons to quadrupolar (6)Li nuclei is combined with dynamic nuclear polarization of protons at 1.2 K and 6.7 T using TEMPOL as a polarizing agent followed by rapid dissolution. Compared to direct (6)Li DNP without cross-polarization, a higher nuclear spin polarization P((6)Li) can be obtained in a shorter time. A double resonance (1)H-(6)Li probe was designed that is equipped for Longitudinally Detected Electron Spin Resonance.

Tuesday, November 4, 2014

[NMR] Postdoctoral Position: Development of Biological Pulsed High-Field EPR Applications

From the Ampere Magnetic Resonance mailing list:

Location: National High Magnetic Field Laboratory, Tallahassee, FL
Start Date: Fall 2014 or early 2015

A postdoctoral position is available in the Electron Magnetic Resonance (EMR) group at the U.S. National High Magnetic Field Laboratory (NHMFL). The position will be focused on the development of biological applications utilizing a recently acquired state-of-the-art pulsed high-frequency (W-band, or 94 GHz) EPR spectrometer (HiPER). The HiPER instrument provides kilowatt powers, enabling nanosecond p/2 pulses. Furthermore, its quasi-optical design gives exceptional cross-polar isolation, enabling induction-mode detection while excitation pulses are incident on the sample. Thus, HiPER offers true nanosecond time resolution and the possibility to perform fourier-transform-type high-field EPR measurements, akin to what is routinely achieved in NMR. HiPER also offers exceptional sensitivity. As such, it is expected to have a major impact on both the materials and biological applications programs at the NHMFL in the coming years. 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 in Tallahassee comprises five faculty-level researchers, as well as a large cohort of graduate students and postdocs. The group also has strong interactions with EPR groups 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 Chemistry, Physics, Biology 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; biological 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:

Stephen Hill
National High Magnetic Field Laboratory
1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA

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Monday, November 3, 2014

Evaluation of Activation Energies for Pairwise and Non-Pairwise Hydrogen Addition to Propyne Over Pd/Aluminosilicate Fiberglass Catalyst by Parahydrogen-Induced Polarization (PHIP)


Salnikov, O.G., et al., Evaluation of Activation Energies for Pairwise and Non-Pairwise Hydrogen Addition to Propyne Over Pd/Aluminosilicate Fiberglass Catalyst by Parahydrogen-Induced Polarization (PHIP). Appl. Magn. Reson., 2014. 45(10): p. 1051-1061.


Hydrogenation of propyne to propene over Pd/aluminosilicate fiberglass catalyst in the temperature range 175–350 °C was investigated with the use of parahydrogen-induced polarization (PHIP) technique. Activation energies for both pairwise and non-pairwise H2 addition routes were estimated. It was found that at 175–275 °C the activation energies for hydrogen addition to the triple bond of propyne have similar values (about 60–70 kJ/mol) for both routes of hydrogen addition. At higher temperatures (275–350 °C), the rate constant for pairwise hydrogen addition reaches a maximum value while the rate constant for non-pairwise hydrogen addition continues to increase with increasing temperature.

Friday, October 31, 2014

Multi-responsive cellulose nanocrystal-rhodamine conjugates – An advanced structure study by solid-state dynamic nuclear polarization (DNP) NMR


Zhao, L., et al., Multi-responsive cellulose nanocrystal-rhodamine conjugates – An advanced structure study by solid-state dynamic nuclear polarization (DNP) NMR. Phys. Chem. Chem. Phys., 2014.


Multi-stimuli responsive materials based on cellulose nanocrystals (CNC), especially using non-conventional stimuli including light, still need more explorations, to fulfill the requirement of complicated application environments. The structure determination of functional groups on CNC surface constitutes a significant challenge, partially due to their low amounts. In this study, rhodamine spiroamide groups are immobilized onto the surface of CNC leading to a hybrid compound being responsive to pH-value, heating and UV light. After the treatment with external stimuli, the fluorescent and correlated optical color change can be induced, which refers to a ring opening and closing process. Amine and amide groups in rhodamine spiroamide play the critical role during this switching process. Solid-state NMR spectroscopy coupled with sensitivity-enhanced dynamic nuclear polarization (DNP) was used to measure 13C and 15N in natural abundance, allowing the determination of structural changes during the switching process. It is shown that a temporary bond through an electrostatic interaction could be formed within the confined environment on the CNC surface during the heating treatment. The carboxyl groups on CNC surface plays a pivotal role in stabilizing the open status of rhodamine spiroamide groups.

Wednesday, October 29, 2014

Direct enzyme-substrate affinity determination by real-time hyperpolarized (13)C-MRS


Friesen-Waldner, L.J., et al., Direct enzyme-substrate affinity determination by real-time hyperpolarized (13)C-MRS. Chem Commun (Camb), 2014. 50(89): p. 13801-4.


A specialized kinetic analysis of real-time hyperpolarized [1,1,2,2-D4, 1-(13)C]choline (13)C-magnetic resonance spectroscopy enabled the determination of initial rates of metabolic enzyme activity (choline oxidase), enzyme-substrate affinity (Km), and inhibition. In a clinical MRI scanner, metabolite levels lower than 16 muM were detected at a temporal resolution of 1 s.

Monday, October 27, 2014

Primostrato Solid-State NMR Enhanced by Dynamic Nuclear Polarization: Pentacoordinated Al3+ Ions Are Only Located at the Surface of Hydrated γ-Alumina


Lee, D., et al., Primostrato Solid-State NMR Enhanced by Dynamic Nuclear Polarization: Pentacoordinated Al3+ Ions Are Only Located at the Surface of Hydrated γ-Alumina. The Journal of Physical Chemistry C, 2014.


Aluminas (Al2O3) are ubiquitous functional materials. In particular, the ?-alumina form is extensively used in research and industry as a catalyst and catalyst support. Nevertheless, a full structural description, which would aid in comprehension of its properties, is lacking and under large debate. Solid-state NMR has been used previously to study ?-alumina but is limited for certain applications, such as surface studies, due to intrinsic low sensitivity. Here, we detail the implementation of low temperature (?100 K) magic angle spinning combined with dynamic nuclear polarization (MAS-DNP) to significantly enhance the sensitivity of solid-state NMR experiments and gain structural insights into this important material. Notably, we analyze hydrophilic and hydrophobic sample preparation protocols and their implications on the sample and resulting NMR parameters. We show that the choice of preparation does not perturb the spectrum, but it does have a large effect on NMR coherence lifetimes, as does the corresponding required (hyper)polarizing agent. We use this preliminary study to optimize the absolute sensitivity of the following experiments. We then show that there are no detectable hydroxyl groups in the bulk of the material and that DNP-enhanced 1H ? 27Al cross-polarization experiments are selective to only the first surface layer, enabling a very specific study. This primostrato NMR is integrated with multiple-quantum magic angle spinning (MQMAS) and it is demonstrated, interestingly, that pentacoordinated Al3+ ions are only observed in this first surface layer. To highlight that there is no evidence of subsurface pentacoordinated Al3+, a new bulk-filtered experiment is described that can eliminate surface signals.

Friday, October 24, 2014

DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature


Jakdetchai, O., et al., DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature. J Am Chem Soc, 2014.


DNP-enhanced solid-state NMR has been shown to hold great potential for functional studies of membrane proteins at low temperatures due to its great sensitivity improvement. There are however numerous applications, for which experiments at ambient temperature are desirable and which would also benefit from DNP signal enhancement. Here, we demonstrate as a proof of concept that a significant signal increase for lipid bilayers under room temperature conditions can be achieved by utilizing the Overhauser effect. Experiments were carried out on aligned bilayers at 400 MHz/263 GHz using a stripline structure combined with a Fabry-Perot microwave resonator. A signal enhancement of protons of up to -10 was observed. Our results demonstrate that Overhauser DNP at high field pro-vides efficient polarization transfer within insoluble samples, which is driven by fast local molecular fluc-tuations. Furthermore, our experimental setup offers an attractive option for DNP-enhanced solid-state NMR on ordered membranes and provides a general perspective towards DNP at ambient temperatures.

Wednesday, October 22, 2014

Selective Host-Guest Interaction between Metal Ions and Metal-Organic Frameworks using Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy


Guo, Z., et al., Selective Host-Guest Interaction between Metal Ions and Metal-Organic Frameworks using Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy. Chemistry, 2014: p. n/a-n/a.


The host-guest interaction between metal ions (Pt2+ and Cu2+ ) and a zirconium metal-organic framework (UiO-66-NH2 ) was explored using dynamic nuclear polarization-enhanced 15 N{1 H} CPMAS NMR spectroscopy supported by X-ray absorption spectroscopy and density functional calculations. The combined experimental results conclude that each Pt2+ coordinates with two NH2 groups from the MOF and two Cl- from the metal precursor, whereas Cu2+ do not form chemical bonds with the NH2 groups of the MOF framework. Density functional calculations reveal that Pt2+ prefers a square-planar structure with the four ligands and resides in the octahedral cage of the MOF in either cis or trans configurations.

Monday, October 20, 2014

Untangling the Condensation Network of Organosiloxanes on Nanoparticles using 2D (29)Si-(29)Si Solid-State NMR Enhanced by Dynamic Nuclear Polarization


Lee, D., et al., Untangling the Condensation Network of Organosiloxanes on Nanoparticles using 2D (29)Si-(29)Si Solid-State NMR Enhanced by Dynamic Nuclear Polarization. J Am Chem Soc, 2014. 136(39): p. 13781-8.


Silica (SiO2) nanoparticles (NPs) were functionalized by silanization to produce a surface covered with organosiloxanes. Information about the surface coverage and the nature, if any, of organosiloxane polymerization, whether parallel or perpendicular to the surface, is highly desired. To this extent, two-dimensional homonuclear (29)Si solid-state NMR could be employed. However, owing to the sensitivity limitations associated with the low natural abundance (4.7%) of (29)Si and the difficulty and expense of isotopic labeling here, this technique would usually be deemed impracticable. Nevertheless, we show that recent developments in the field of dynamic nuclear polarization under magic angle spinning (MAS-DNP) could be used to dramatically increase the sensitivity of the NMR experiments, resulting in a timesaving factor of approximately 625 compared to conventional solid-state NMR. This allowed the acquisition of previously infeasible data. Using both through-space and through-bond 2D (29)Si-(29)Si correlation experiments, it is shown that the required reaction conditions favor lateral polymerization and domain growth. Moreover, the natural abundance correlation experiments permitted the estimation of (2)J(Si-O-Si)-couplings (13.8 +/- 1.4 Hz for surface silica) and interatomic distances (3.04 +/- 0.08 A for surface silica) since complications associated with many-spin systems and also sensitivity were avoided. The work detailed herein not only demonstrates the possibility of using MAS-DNP to greatly facilitate the acquisition of 2D (29)Si-(29)Si correlation spectra but also shows that this technique can be used in a routine fashion to characterize surface grafting networks and gain structural constraints, which can be related to a system's chemical and physical properties.

Friday, October 17, 2014

Detecting a New Source for Photochemically Induced Dynamic Nuclear Polarization in the LOV2 Domain of Phototropin by Magnetic-Field Dependent 13C NMR Spectroscopy


Kothe, G., et al., Detecting a New Source for Photochemically Induced Dynamic Nuclear Polarization in the LOV2 Domain of Phototropin by Magnetic-Field Dependent 13C NMR Spectroscopy. The Journal of Physical Chemistry B, 2014. 118(40): p. 11622-11632.


Phototropin is a flavin mononucleotide (FMN) containing blue-light receptor, which regulates, governed by its two LOV domains, the phototropic response of higher plants. Upon photoexcitation, the FMN cofactor triplet state, 3F, reacts with a nearby cysteine to form a covalent adduct. Cysteine-to-alanine mutants of LOV domains instead generate a flavin radical upon illumination. Here, we explore the formation of photochemically induced dynamic nuclear polarization (CIDNP) in LOV2-C450A of Avena sativa phototropin and demonstrate that photo-CIDNP observed in solution 13C NMR spectra can reliably be interpreted in terms of solid-state mechanisms including a novel triplet mechanism. To minimize cross-polarization, which transfers light-induced magnetization to adjacent 13C nuclei, our experiments were performed on proteins reconstituted with specifically 13C-labeled flavins. Two potential sources for photo-CIDNP can be identified: The photogenerated triplet state, 3F, and the triplet radical pair 3(F??W+?), formed by electron abstraction of 3F from tryptophan W491. To separate the two contributions, photo-CIDNP studies were performed at four different magnetic fields ranging from 4.7 to 11.8 T. Analysis revealed that, at fields <9 T, both 3(F??W+?) and 3F contribute to photo-CIDNP, whereas at high magnetic fields, the calculated enhancement factors of 3F agree favorably with their experimental counterparts. Thus, we have for the first time detected that a triplet state is the major source for photo-CIDNP in a photoactive protein. Since triplet states are frequently encountered upon photoexcitation of flavoproteins, the novel triplet mechanism opens up new means of studying electronic structures of the active cofactors in these proteins at atomic resolution.

Wednesday, October 15, 2014

Long-lived localization in magnetic resonance imaging


Dumez, J.-N., et al., Long-lived localization in magnetic resonance imaging. J. Magn. Reson., 2014. 246(0): p. 27-30.


The longitudinal nuclear relaxation time, T1, sets a stringent limit on the range of information that can be obtained from magnetic resonance imaging (MRI) experiments. Long-lived nuclear spin states provide a possibility to extend the timescale over which information can be encoded in magnetic resonance. We introduce a strategy to localize an ensemble of molecules for a significantly extended duration (∼30 times longer than T1 in this example), using a spatially selective conversion between magnetization and long-lived singlet order. An application to tagging and transport is proposed.

Tuesday, October 14, 2014

Post-doctoral position at CEA-Saclay in NMR hardware development

From the Ampere Magnetic Resonance List


Post-doctoral position at CEA-Saclay in NMR hardware development

We are looking for post-doctoral candidates, to join an exciting project on the development of a new approach to increase sensitivity with NMR spectroscopy. The project aims at developing magic angle coil spinning (MACS) for high-resolution micro-detection of volume-limited biomedical substances, using Dynamic Nuclear Polarization (DNP) and is funded by the French National Science Foundation (ANR). The role of the post-doc associate will be to participate in the development of new hardware on high-field and ultra-high field spectrometers. This project is pursued in close collaboration with the University Pierre and Marie Curie and the group of Prof. Christian Bonhomme.

Post-doctoral candidates should have strong experience in electrical engineering and/or magnetic resonance hardware development (e.g. radio-frequency probes, antennas), or connected areas of experimental physics and engineering.

Funding is available for at least one year, while possibilities for up to 30 months are accessible. Salary will be commensurate with experience.

Our team (http://dsakellariou.free.fr) is part of the laboratory of structure and dynamics by magnetic resonance lab (http://iramis.cea.fr/sis2m/lsdrm/), at the Department of Material Science division of CEA (http://www.cea.fr/english-portal). The group offers a unique environment where the research activity on magnetic resonance methodology and instrumentation encompasses pulse sequence development for solid-state NMR and MRI. The CEA is located 20 km from the heart of Paris, at the center of an extremely dynamic scientific cluster (http://www.epps.fr/en/a-global-cluster/).

Interested candidates should send their full CV to Dimitrios Sakellariou (Dimitrios.Sakellariou@cea.fr) and provide three references in a cover letter.

D. Sakellariou

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Monday, October 13, 2014

Coherent Polarization Transfer Effects Are Crucial for Interpreting Low-Field CIDNP Data


Panov, M., et al., Coherent Polarization Transfer Effects Are Crucial for Interpreting Low-Field CIDNP Data. Appl. Magn. Reson., 2014. 45(9): p. 893-900.


In this work we demonstrate that low-field chemically induced dynamic nuclear polarization (CIDNP) is strongly affected by re-distribution of polarization, which is formed in the course of spin evolution in transient radical pairs, in diamagnetic reaction products. This phenomenon is of importance when the spins of the reaction product are coupled strongly meaning that spin–spin interactions between them are comparable to the differences in their Zeeman interactions with the external magnetic field. In this case, polarization transfer relies on a coherent mechanism; as a consequence, spins can acquire significant polarization even when they have no hyperfine coupling to the electron spins in the radical pairs, i.e., cannot be polarized directly by CIDNP. This is demonstrated by taking CIDNP of n-butylamine as an example: in this case only the α-CH2 protons are polarized directly, which is confirmed by high-field CIDNP, whereas the β-CH2, γ-CH2 and δ-CH3 protons get polarized only indirectly due to the transfer of polarization from the α-CH2 protons. These results show that low-field CIDNP data should be interpreted with care to discriminate between the effects of spin evolution in transient radical pairs and in diamagnetic reaction products.

Friday, October 10, 2014

Solid State Field-Cycling NMR Relaxometry: Instrumental Improvements and New Applications


Fujara, F., D. Kruk, and A.F. Privalov, Solid State Field-Cycling NMR Relaxometry: Instrumental Improvements and New Applications. Prog. NMR. Spec., (0).


The paper reviews recent progress in field cycling (FC) NMR instrumentation and its application to solid state physics. Special emphasis is put on our own work during the last 15 years on instrumentation, theory and applications. As far as instrumentation is concerned we report on our development of two types of electronical FC relaxometers, a mechanical FC relaxometer and a combination of FC and one-dimensional microimaging. Progress has been achieved with respect to several parameters such as the accessible field and temperature range as well as the incorporation of sample spinning. Since an appropriate analysis of FC data requires a careful consideration of relaxation theory, we include a theory section discussing the most relevant aspects of relaxation in solids which are related to prevailing residual dipolar and quadrupolar interactions. The most important limitations of relaxation theory are also discussed. With improved instrumentation and with the help of relaxation theory we get access to interesting new applications such as ionic motion in solid electrolytes, structure determination in molecular crystals, ultraslow polymer dynamics and rotational resonance phenomena.

Wednesday, October 8, 2014

Cross-polarization for dissolution dynamic nuclear polarization


Batel, M., et al., Cross-polarization for dissolution dynamic nuclear polarization. Phys Chem Chem Phys, 2014. 16(39): p. 21407-16.


Dynamic nuclear polarization (DNP) in combination with subsequent dissolution of the sample allows the detection of low-gamma nuclei in the solution state with a signal gain of up to tens of thousand times compared to experiments starting from Boltzmann conditions. The long polarization build-up times of typically more than one hour are a drawback of this technique. The combination of dissolution DNP with cross-polarization (CP) in the solid state was shown to have the potential to overcome this disadvantage. In this article we discuss the cross-polarization step under dissolution DNP conditions in more detail. We show that adiabatic half-passage pulses allow us to enhance the CP efficiency in power-limited DNP probes. As a low-power alternative to Hartmann-Hahn CP we also demonstrate the applicability of frequency-swept de- and re-magnetization pulses for polarization transfer via dipolar order. We investigate the implications and restrictions of the common solid-state DNP mechanisms to the DNP-CP technique and apply a spin-thermodynamic model based on the thermal-mixing mechanism. The model allows us to investigate the dynamics of the polarization levels in a system with two nuclear Zeeman reservoirs and explains the enhanced DNP efficiency upon solvent deuteration within a spin-thermodynamic picture.

Postdoc Position: Metabolic Imaging using hyperpolarized 13C MR

From the Ampere Magnetic Resonance List



Technische Universität München, Munich, Germany
Postdoc Position: Metabolic Imaging using hyperpolarized 13C MR

We are looking for a postdoc who will join our project within the Collaborative Research Centre 824 Imaging for Selection, Monitoring and Individualization of Cancer Therapies at the Department of Nuclear Medicine at the Technische Universität München (Germany).The initial employment has a duration of 1.5 years (extension is possible) starting December 1st, 2014. The salary is according to TV-L E13.

The Department of Nuclear Medicine at Technische Universität München, Germany, is internationally highly regarded in the field of molecular imaging. Since many years, multimodal imaging (SPECT, PET, MRI, CT) in clinical and preclinical applications is a core focus of our department. Recently a 7 T MRI scanner (GE MR901) for preclinical applications has been installed together with a HyperSense DNP Polarizer for hyperpolarized 13C MR imaging.

We are looking for a postdoc with strong background in metabolic, preclinical imaging, metabolomics and broad experience in animal models to join this preclinical 7T MRI laboratory including the DNP Polarizer. The person is expected to take on the role of the biomedical expert, bringing in the strong expertise on preclinical models of cancer and their establishment in animals (rat, mice). The person will further be responsible for research design, internal and external collaborations for preclinical imaging, and study-execution, working closely together with the team of PhD students and the 7T responsible physicist. In addition, the candidate is expected to develop his/her own research focus within the framework of the department’s scientific goals.

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

Applications should include a cover letter, a CV and a list of own publications together with the names of three references and should be sent to: marion.menzel@tum.de

Dr. Marion I. Menzel
Senior Scientist
Diagnostics, Imaging and Biomedical Technologies Europe
GE Global Research 

T +49 89 55283-730

M +49 173 9441337
F +49 89 55283-180 


Freisinger Landstrasse 50
85748 Garching bei München
Germany

GE imagination at work

GE Global Research, Zweigniederlassung der General Electric Deutschland Holding GmbH. Sitz von/Registered Office of General Electric Deutschland Holding GmbH: Frankfurt/Main.
Registergericht/Commercial Register: Amtsgericht/Lower District Court Frankfurt; HRB 98088. Geschäftsführer/Managing Director: Ferdinando Beccalli-Falco, Prof. Dr. Ing. Stephan Reimelt, Dr. Volker Wetekam, Dr. Carlos Härtel, Udo Josef Klaeren, Werner van Wickeren.

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Friday, September 26, 2014

Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR


Buratto, R., et al., Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR. ChemMedChem, 2014: p. n/a-n/a.


Transverse and longitudinal relaxation times (T1rho and T1 ) have been widely exploited in NMR to probe the binding of ligands and putative drugs to target proteins. We have shown recently that long-lived states (LLS) can be more sensitive to ligand binding. LLS can be excited if the ligand comprises at least two coupled spins. Herein we broaden the scope of ligand screening by LLS to arbitrary ligands by covalent attachment of a functional group, which comprises a pair of coupled protons that are isolated from neighboring magnetic nuclei. The resulting functionalized ligands have longitudinal relaxation times T1 (1 H) that are sufficiently long to allow the powerful combination of LLS with dissolution dynamic nuclear polarization (D-DNP). Hyperpolarized weak "spy ligands" can be displaced by high-affinity competitors. Hyperpolarized LLS allow one to decrease both protein and ligand concentrations to micromolar levels and to significantly increase sample throughput.

Wednesday, September 24, 2014

Determination of sample temperature in unstable static fields by combining solid-state 79Br and 13C NMR

This is not an article about DNP-NMR spectroscopy, however, it deals with the measurements of temperatures in solid-state NMR experiments using KBR and referencing its chemical shift to 13C of adamantane in unstable magnetic fields.




Purusottam, R.N., G. Bodenhausen, and P. Tekely, Determination of sample temperature in unstable static fields by combining solid-state (79)Br and (13)C NMR. J Magn Reson, 2014. 246(0): p. 69-71.


Monitoring the isotropic chemical shifts to calibrate the sample temperature presupposes a perfect stability of the static magnetic field. It can be difficult to satisfy this requirement in solid-state NMR measurements. This paper describes a simple way to recover the accurate temperature dependence of the (79)Br resonance after subtracting changes of resonance frequency due to variations of the static field, monitored by the (13)C resonance.

Meet Bridge12 at the FGMR Meeting in Berlin

I will be at the Fachgruppe Magnetische Resonance (FGMR) Meeting in Berlin, September 29th - October 2nd, and at the one-day meeting 'Progress in DNP' September 29th.

If you would like to know about our products such as gyrotrons for DNP, frequency measurement systems, calorimetric power loads or corrugated transmission lines, or generally want to chat about DNP-NMR feel free to pull me aside or contact me at tmaly@bridge12.com.

For more information about the FGMR meeting visit the conference website.

Cheers,
Thorsten

Friday, September 19, 2014

PostDoc Position at Institut for Biomedical Engineering, ETH Zurich

From the Ampere Magnetic Resonance List


The Institute for Biomedical Engineering at the University and ETH Zurich in collaboration with the Laboratory of Physical Chemistry at ETH Zurich is offering following position:

Postdoctoral Fellow in Hyperpolarized Magnetic Resonance

Magnetic Resonance (MR) imaging is a prime diagnostic modality today. Despite its success, MR remains a relatively insensitive technique when probing nuclei other than protons. To this end, dissolution Dynamic Nuclear Polarization (DNP) methods have shown great promise to provide signal enhancements by orders of magnitude over short periods of time.

The position offered concerns further development and application of the dissolution DNP principle of various nuclei including carbon-13 and silicon-29. The project is embedded in a program aimed at developing novel methods to hyperpolarize and image the fate of metabolically active substrates and functionalized particles.

The University and ETH Zurich offer an international and stimulating research environment with first class infrastructure including the full range of clinical and experimental Magnetic Resonance systems as well as an excellent network of scientific and industrial partners.

Requirements
• PhD in physics, physical chemistry or biomedical engineering
• Fundamental knowledge of NMR, ESR, MRI, MRS
• Fluent in computer programming (Matlab, C)
• Interest in magnetic resonance hardware and experimentation
• Innovative spirit, team player

Contact:
Prof Dr Sebastian Kozerke
Institute for Biomedical Engineering 
University and ETH Zurich 
Gloriastrasse 35, 8092 Zurich
+41 44 632 3549 

- -- 

+----------------------------------------+-----------------------------------+
| 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 |
+----------------------------------------+-----------------------------------+

Short-term postdoctoral position DNP MRI/SRM in Bordeaux

From the Ampere Magnetic Resonance List:


Postdoctoral position in DNP MR imaging and NMR spectroscopy Centre de Résonance Magnétique des Systèmes Biologiques Bordeaux, France

Position description

A short-term (6 months) postdoctoral position is available at the Center for Magnetic Resonance of Biological Systems located in Bordeaux, France. The position will focus on hyperpolarized carbon-13 spectroscopy and imaging.

Qualifications

Due to the short duration of the contract, the candidate will ideally have a previous experience in the field of MRS/MRI of hyperpolarized media and Dynamic Nuclear Polarization techniques. 

Facilities

The RMSB Center operates a dissolution DNP polarizer dedicated to MRI/MRS biomedical applications, two small animal Bruker MRI system (4.7 T and 7 T) and two high-resolution NMR spectrometer (400 and 500 MHz). The RMSB Center is composed of 40 scientists involved in development and applications of biomedical MRS/MRI. The Center is located on the Life Sciences and hospital campus at 10 minutes from the city center with public transportation.

Environment

Bordeaux is a 1-million urban area and hosts one of the largest university and research community in France. Located in South west of France in close proximity of the Atlantic Ocean, the city, part of the World Heritage List, offers a wide range of cultural and outdoors activities.

Conditions of employment

The duration of the position is 6 months with a net monthly salary of ~2100 euros.
The position is open from 1st November 2014
For more information and application please contact:

Yannick Crémillieux, yannick.cremillieux@u-bordeaux.fr

-- 
Yannick Crémillieux
PhD, DR CNRS
CRMSB, UMR 5536
Université Bordeaux 2
146, rue Léo-Saignat
33076 BORDEAUX Cedex

Tél: +33 (0)547304253
Fax: +33 (0)557574556

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Radical-free dynamic nuclear polarization using electronic defects in silicon


Cassidy, M.C., et al., Radical-free dynamic nuclear polarization using electronic defects in silicon. Physical Review B, 2013. 87(16): p. 161306.


Direct dynamic nuclear polarization of 1H nuclei in frozen water and water-ethanol mixtures is demonstrated using silicon nanoparticles as the polarizing agent. Electron spins at dangling-bond sites near the silicon surface are identified as the source of the nuclear hyperpolarization. This polarization method opens avenues for the fabrication of surface engineered nanostructures to create high nuclear spin polarized solutions without introducing contaminating radicals, and for the study of molecules adsorbed onto surfaces.

Wednesday, September 17, 2014

Spectral editing through laser-flash excitation in two-dimensional photo-CIDNP MAS NMR experiments


Sai Sankar Gupta, K.B., et al., Spectral editing through laser-flash excitation in two-dimensional photo-CIDNP MAS NMR experiments. J Magn Reson, 2014. 246C(0): p. 9-17.


In solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) MAS NMR experiments, strong signal enhancement is observed from molecules forming a spin-correlated radical pair in a rigid matrix. Two-dimensional 13C-13C dipolar-assisted rotational resonance (DARR) photo-CIDNP MAS NMR experiments have been applied to obtain exact chemical shift assignments from those cofactors. Under continuous illumination, the signals are enhanced via three-spin mixing (TSM) and differential decay (DD) and their intensity corresponds to the electron spin density in pz orbitals. In multiple-13C labelled samples, spin diffusion leads to propagation of signal enhancement to all 13C spins. Under steady-state conditions, direct signal assignment is possible due to the uniform signal intensity. The original intensities, however, are inaccessible and the information of the local electron spin density is lost. Upon laser-flash illumination, the signal is enhanced via the classical radical pair mechanism (RPM). The obtained intensities are related to isotropic hyperfine interactions aiso and both enhanced absorptive and emissive lines can be observed due to differences in the sign of the local isotropic hyperfine interaction. Exploiting the mechanism of the polarization, selectivity can be increased by the novel time-resolved two-dimensional dipolar-assisted rotational resonance (DARR) MAS NMR experiment which simplifies the signal assignment compared to complex spectra of the same RCs obtained by continuous illumination. Here we present two-dimensional time-resolved photo-CIDNP MAS NMR experiments providing both directly: signal assignment and spectral editing by sign and strength of aiso. Hence, this experiment provides a direct key to the electronic structure of the correlated radical pair.

Monday, September 15, 2014

Long-lived localization in magnetic resonance imaging


Dumez, J.N., et al., Long-lived localization in magnetic resonance imaging. J Magn Reson, 2014. 246C(0): p. 27-30.


The longitudinal nuclear relaxation time, T1, sets a stringent limit on the range of information that can be obtained from magnetic resonance imaging (MRI) experiments. Long-lived nuclear spin states provide a possibility to extend the timescale over which information can be encoded in magnetic resonance. We introduce a strategy to localize an ensemble of molecules for a significantly extended duration ( approximately 30 times longer than T1 in this example), using a spatially selective conversion between magnetization and long-lived singlet order. An application to tagging and transport is proposed.

Friday, September 12, 2014

Achieving 1% NMR polarization in water in less than 1min using SABRE


Zeng, H., et al., Achieving 1% NMR polarization in water in less than 1min using SABRE. J Magn Reson, 2014. 246C(0): p. 119-121.


The development of biocompatible hyperpolarized media is a crucial step towards application of hyperpolarization in vivo. This article describes the achievement of 1% hyperpolarization of 3-amino-1,2,4-triazine protons in water using the parahydrogen induced polarization technique based on signal amplification by reversible exchange (SABRE). Polarization was achieved in less than 1min.

Wednesday, September 10, 2014

Dipolar Induced Para-Hydrogen-Induced Polarization


Buntkowsky, G., et al., Dipolar Induced Para-Hydrogen-Induced Polarization. Solid State Nuclear Magnetic Resonance, 2014(0).


Analytical expressions for the signal enhancement in solid-state PHIP NMR spectroscopy mediated by homonuclear dipolar interactions and single pulse or spin-echo excitation are developed and simulated numerically. It is shown that an efficient enhancement of the proton NMR signal in solid-state NMR studies of chemisorbed hydrogen on surfaces is possible. Employing typical reaction efficacy, enhancement-factors of ca. 30–40 can be expected both under ALTADENA and under PASADENA conditions. This result has important consequences for the practical application of the method, since it potentially allows the design of an in-situ flow setup, where the para-hydrogen is adsorbed and desorbed from catalyst surfaces inside the NMR magnet.

Monday, September 8, 2014

Overhauser effects in insulating solids


Can, T.V., et al., Overhauser effects in insulating solids. J Chem Phys, 2014. 141(6): p. 064202.


We report magic angle spinning, dynamic nuclear polarization (DNP) experiments at magnetic fields of 9.4 T, 14.1 T, and 18.8 T using the narrow line polarizing agents 1,3-bisdiphenylene-2-phenylallyl (BDPA) dispersed in polystyrene, and sulfonated-BDPA (SA-BDPA) and trityl OX063 in glassy glycerol/water matrices. The (1)H DNP enhancement field profiles of the BDPA radicals exhibit a significant DNP Overhauser effect (OE) as well as a solid effect (SE) despite the fact that these samples are insulating solids. In contrast, trityl exhibits only a SE enhancement. Data suggest that the appearance of the OE is due to rather strong electron-nuclear hyperfine couplings present in BDPA and SA-BDPA, which are absent in trityl and perdeuterated BDPA (d21-BDPA). In addition, and in contrast to other DNP mechanisms such as the solid effect or cross effect, the experimental data suggest that the OE in non-conducting solids scales favorably with magnetic field, increasing in magnitude in going from 5 T, to 9.4 T, to 14.1 T, and to 18.8 T. Simulations using a model two spin system consisting of an electron hyperfine coupled to a (1)H reproduce the essential features of the field profiles and indicate that the OE in these samples originates from the zero and double quantum cross relaxation induced by fluctuating hyperfine interactions between the intramolecular delocalized unpaired electrons and their neighboring nuclei, and that the size of these hyperfine couplings is crucial to the magnitude of the enhancements. Microwave power dependent studies show that the OE saturates at considerably lower power levels than the solid effect in the same samples. Our results provide new insights into the mechanism of the Overhauser effect, and also provide a new approach to perform DNP experiments in chemical, biophysical, and physical systems at high magnetic fields.

Training School on Hyperpolarization Techniques


Dear All,

The next COST Training School on Hyperpolarization techniques will be held on 20-24th October 2014, nearby Marseille.

The topics will include Dissolution DNP, MAS ssNMR / DNP, liquid DNP, Theory of polarization mechanisms (SE, CE, OE, static and MAS DNP, TM), High-field EPR, CIDNP, ONP, Hyperpolarized gas, Para Hydrogen Induced Polarization and application of DNP techniques.

This is a unique occasion to meet and discuss with leading actors involved in DNP breakthroughs in the frame of a training school.

The school is limited to 30 participants! 

Grants will be offered by EuroHyperPol COST Action program (TD1103) and the grant will be delivered after the School.


Looking forward to see you on the seaside !
Olivier Ouari and Paul Tordo

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Aix-Marseille Universite / CNRS
Faculte ed Saint Jerome case 521
13013 Marseille, France.