Friday, March 31, 2017

Hyperpolarized Multi-Metal 13C-Sensors for Magnetic Resonance Imaging


Mishra, A., et al., Hyperpolarized Multi-Metal 13C-Sensors for Magnetic Resonance Imaging. Anal Chem, 2016. 88(22): p. 10790-10794.


We introduce hyperpolarizable 13C-labeled probes that identify multiple biologically important divalent metals via metal-specific chemical shifts. These features enable NMR measurements of calcium concentrations in human serum in the presence of magnesium. In addition, signal enhancement through dynamic nuclear polarization (DNP) increases the sensitivity of metal detection to afford measuring micromolar concentrations of calcium as well as simultaneous multi-metal detection by chemical shift imaging. The hyperpolarizable 13C-MRI sensors presented here enable sensitive NMR measurements and MR imaging of multiple divalent metals in opaque biological samples.

Wednesday, March 29, 2017

Quantitative analysis of molecular transport across liposomal bilayer by J-mediated 13C Overhauser dynamic nuclear polarization


Cheng, C.Y., O.J. Goor, and S. Han, Quantitative analysis of molecular transport across liposomal bilayer by J-mediated 13C Overhauser dynamic nuclear polarization. Anal Chem, 2012. 84(21): p. 8936-40.


We introduce a new NMR technique to dramatically enhance the solution-state (13)C NMR sensitivity and contrast at 0.35 T and at room temperature by actively transferring the spin polarization from Overhauser dynamic nuclear polarization (ODNP)-enhanced (1)H to (13)C nuclei through scalar (J) coupling, a method that we term J-mediated (13)C ODNP. We demonstrate the capability of this technique by quantifying the permeability of glycine across negatively charged liposomal bilayers composed of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG). The permeability coefficient of glycine across this DPPC/DPPG bilayer is measured to be (1.8 +/- 0.1) x 10(-11)m/s, in agreement with the literature value. We further observed that the presence of 20 mol % cholesterol within the DPPC/DPPG lipid membrane significantly retards the permeability of glycine by a factor of 4. These findings demonstrate that the high sensitivity and contrast of J-mediated (13)C ODNP affords the measurement of the permeation kinetics of small hydrophilic molecules across lipid bilayers, a quantity that is difficult to accurately measure with existing techniques.

Monday, March 27, 2017

The effect of Gd on trityl-based dynamic nuclear polarisation in solids


Ravera, E., et al., The effect of Gd on trityl-based dynamic nuclear polarisation in solids. Phys. Chem. Chem. Phys., 2015. 17(40): p. 26969-78.


In dynamic nuclear polarisation (DNP) experiments performed under static conditions at 1.4 K we show that the presence of 1 mM Gd(iii)-DOTAREM increases the (13)C polarisation and decreases the (13)C polarisation buildup time of (13)C-urea dissolved in samples containing water/DMSO mixtures with trityl radical (OX063) concentrations of 10 mM or higher. To account for these observations further measurements were carried out at 6.5 K, using a combined EPR and NMR spectrometer. At this temperature, frequency swept DNP spectra of samples with 5 or 10 mM OX063 were measured, with and without 1 mM Gd-DOTA, and again a (13)C enhancement gain was observed due to the presence of Gd-DOTA. These measurements were complemented by electron-electron double resonance (ELDOR) measurements to quantitate the effect of electron spectral diffusion (eSD) on the DNP enhancements and lineshapes. Simulations of the ELDOR spectra were done using the following parameters: (i) a parameter defining the rate of the eSD process, (ii) an "effective electron-proton anisotropic hyperfine interaction parameter", and (iii) the transverse electron spin relaxation time of OX063. These parameters, together with the longitudinal electron spin relaxation time, measured by EPR, were used to calculate the frequency profile of electron polarisation. This, in turn, was used to calculate two basic solid effect (SE) and indirect cross effect (iCE) DNP spectra. A properly weighted combination of these two normalized DNP spectra provided a very good fit of the experimental DNP spectra. The best fit simulation parameters reveal that the addition of Gd(iii)-DOTA causes an increase in both the SE and the iCE contributions by similar amounts, and that the increase in the overall DNP enhancements is a result of narrowing of the ELDOR spectra (increased electron polarisation gradient across the EPR line). These changes in the electron depolarisation profile are a combined result of shortening of the longitudinal and transverse electron spin relaxation times, as well as an increase in the eSD rate and in the effective electron-proton anisotropic hyperfine interaction parameter.

Friday, March 24, 2017

Parallelized Ligand Screening Using Dissolution Dynamic Nuclear Polarization


Kim, Y., M. Liu, and C. Hilty, Parallelized Ligand Screening Using Dissolution Dynamic Nuclear Polarization. Anal Chem, 2016. 88(22): p. 11178-11183.


Protein-ligand interactions are frequently screened using nuclear magnetic resonance (NMR) spectroscopy. The dissociation constant (KD) of a ligand of interest can be determined via a spin-spin relaxation measurement of a reporter ligand in a single scan when using hyperpolarization by means of dissolution dynamic nuclear polarization (D-DNP). Despite nearly instantaneous signal acquisition, a limitation of D-DNP for the screening of protein-ligand interactions is the required polarization time on the order of tens of minutes. Here, we introduce a multiplexed NMR experiment, where a single hyperpolarized ligand sample is rapidly mixed with protein injected into two flow cells. NMR detection is achieved simultaneously on both channels, resulting in a chemical shift resolved spin relaxation measurement. Spectral resolution allows the use of reference compounds for accurate quantification of concentrations. Simultaneous use of two concentration ratios between protein and ligand broadens the range of KD that is accurately measurable in a single experiment to at least an order of magnitude. In a comparison of inhibitors for the protein trypsin, the average KD values of benzamidine and benzylamine were found to be 12.6 +/- 1.4 muM and 207 +/- 22 muM from three measurements, based on KD = 142 muM assumed known for the reporter ligand 4-(trifluoromethyl)benzene-1-carboximidamide. Typical confidence ranges at 95% evaluated for single experiments were (8.3 muM, 20 muM) and (151 muM, 328 muM). The multiplexed detection of two or more hyperpolarized samples increases throughput of D-DNP by the same factor, improving the applicability to most multipoint measurements that would traditionally be achieved using titrations.

Wednesday, March 22, 2017

Perspectives for hyperpolarisation in compact NMR


Halse, M.E., Perspectives for hyperpolarisation in compact NMR. TrAC Trends in Analytical Chemistry, 2016. 83, Part A: p. 76-83.


Nuclear magnetic resonance (NMR) is one of the most powerful analytical techniques currently available, with applications in fields ranging from synthetic chemistry to clinical diagnosis. Due to the size and cost of high-field spectrometers, NMR is generally considered to be ill-suited for industrial environments and field work. This conventional wisdom is currently being challenged through the development of NMR systems that are smaller, cheaper, more robust and portable. Despite remarkable progress in this area, potential applications are often limited by low sensitivity. Hyperpolarisation techniques have the potential to overcome this limitation and revolutionise the use of compact NMR. This review describes the state-of-the-art in NMR hyperpolarisation and presents promising examples of its application to compact NMR. Both the benefits and challenges associated with the different hyperpolarisation approaches are discussed and applications where these technologies have the potential to make a significant impact are highlighted.

Monday, March 20, 2017

Dynamic Nuclear Polarization Signal Enhancement with High-Affinity Biradical Tags #DNPNMR


Rogawski, R., et al., Dynamic Nuclear Polarization Signal Enhancement with High-Affinity Biradical Tags. The Journal of Physical Chemistry B, 2017. 121(6): p. 1169-1175.

http://dx.doi.org/10.1021/acs.jpcb.6b09021

Dynamic nuclear polarization is an emerging technique for sensitizing solid-state NMR experiments by transferring polarization from electrons to nuclei. Stable biradicals, the polarization source for the cross effect mechanism, are typically codissolved at millimolar concentrations with proteins of interest. Here we describe the high-affinity biradical tag TMP-T, created by covalently linking trimethoprim, a nanomolar affinity ligand of dihydrofolate reductase (DHFR), to the biradical polarizing agent TOTAPOL. With TMP-T bound to DHFR, large enhancements of the protein spectrum are observed, comparable to when TOTAPOL is codissolved with the protein. In contrast to TOTAPOL, the tight binding TMP-T can be added stoichiometrically at radical concentrations orders of magnitude lower than in previously described preparations. Benefits of the reduced radical concentration include reduced spectral bleaching, reduced chemical perturbation of the sample, and the ability to selectively enhance signals for the protein of interest.

Friday, March 17, 2017

One-thousand-fold enhancement of high field liquid nuclear magnetic resonance signals at room temperature


Liu, G., et al., One-thousand-fold enhancement of high field liquid nuclear magnetic resonance signals at room temperature. Nat Chem, 2017. advance online publication.


Nuclear magnetic resonance (NMR) is a fundamental spectroscopic technique for the study of biological systems and materials, molecular imaging and the analysis of small molecules. It detects interactions at very low energies and is thus non-invasive and applicable to a variety of targets, including animals and humans. However, one of its most severe limitations is its low sensitivity, which stems from the small interaction energies involved. Here, we report that dynamic nuclear polarization in liquid solution and at room temperature can enhance the NMR signal of 13C nuclei by up to three orders of magnitude at magnetic fields of ∼3 T. The experiment can be repeated within seconds for signal averaging, without interfering with the sample magnetic homogeneity. The method is therefore compatible with the conditions required for high-resolution NMR. Enhancement of 13C signals on various organic compounds opens up new perspectives for dynamic nuclear polarization as a general tool to increase the sensitivity of liquid NMR.

Wednesday, March 15, 2017

Biosilica-Entrapped Enzymes Studied by Using Dynamic Nuclear-Polarization-Enhanced High-Field NMR Spectroscopy #DNPNMR


Ravera, E., et al., Biosilica-Entrapped Enzymes Studied by Using Dynamic Nuclear-Polarization-Enhanced High-Field NMR Spectroscopy. ChemPhysChem, 2015. 16(13): p. 2751-2754.


Enzymes are used as environmentally friendly catalysts in many industrial applications, and are frequently immobilized in a matrix to improve their chemical stability for long-term storage and reusability. Recently, it was shown that an atomic-level description of proteins immobilized in a biosilica matrix can be attained by examining their magic-angle spinning (MAS) NMR spectra. However, even though MAS NMR is an excellent tool for determining structure, it is severely hampered by sensitivity. In this work we provide the proof of principle that NMR characterization of biosilica-entrapped enzymes could be assisted by high-field dynamic nuclear polarization (DNP).

Monday, March 13, 2017

[NMR] PhD Position, Optically pumped DNP, University of Huddersfield (UK)

PhD place available for 18th September 2017 start, fully funded for UK and EU citizens.

Application Deadline 26th March 2017

Project Title: Optically Generated Sensitivity Enhancements in Magnetic Resonance Spectroscopy

Nuclear Magnetic Resonance (NMR) is a powerful analytical technique used extensively in chemistry and structural biology, but low sensitivity hinders the development of new applications. Laser illumination of certain dye solutions generates triplet states which interact with stable radicals to produce a large electron spin-polarization. We have recently shown this polarization transfers to nuclei, boosting NMR sensitivity when the laser is switched on. You will develop this exciting new method for use at higher magnetic field strengths and investigate the underlying kinetics. Full training will be given in the necessary aspects of Electron Spin Resonance (ESR), NMR and laser spectroscopies.

Please contact the supervisor as soon as possible for an informal discussion.
Dr Chris Wedge
Tel: +44 1484 471614

To apply, please send an email outlining your motivation and experience to the supervisor, including a CV and the names of two referees by 26th March 2017 (copy to f.cross@hud.ac.uk) and complete an on-line application form.

Successful applicants will have a very good first or upper second degree in a relevant subject (e.g. chemistry or physics).


--

Dr Chris Wedge FHEA, MRSC
Senior Lecturer in Physical Chemistry
T +44(0) 1484 47 1614 Twitter @spinchemist
ORCID 0000-0002-3686-1043
School of Applied Sciences
University of Huddersfield | Queensgate | Huddersfield | HD1 3DH

University of Huddersfield inspiring tomorrow's professionals.

This transmission is confidential and may be legally privileged. If you receive it in error, please notify us immediately by e-mail and remove it from your system. If the content of this e-mail does not relate to the business of the University of Huddersfield, then we do not endorse it and will accept no liability.

====================================
This is the AMPERE MAGNETIC RESONANCE mailing list:

NMR web database:

Chemical-shift-resolved (1)(9)F NMR spectroscopy between 13.5 and 135 MHz: Overhauser-DNP-enhanced diagonal suppressed correlation spectroscopy


George, C. and N. Chandrakumar, Chemical-shift-resolved (1)(9)F NMR spectroscopy between 13.5 and 135 MHz: Overhauser-DNP-enhanced diagonal suppressed correlation spectroscopy. Angew Chem Int Ed Engl, 2014. 53(32): p. 8441-4.


Overhauser-DNP-enhanced homonuclear 2D (19)F correlation spectroscopy with diagonal suppression is presented for small molecules in the solution state at moderate fields. Multi-frequency, multi-radical studies demonstrate that these relatively low-field experiments may be operated with sensitivity rivalling that of standard 200-1000 MHz NMR spectroscopy. Structural information is accessible without a sensitivity penalty, and diagonal suppressed 2D NMR correlations emerge despite the general lack of multiplet resolution in the 1D ODNP spectra. This powerful general approach avoids the rather stiff excitation, detection, and other special requirements of high-field (19)F NMR spectroscopy.

Friday, March 10, 2017

A ferromagnetic shim insert for NMR magnets – Towards an integrated gyrotron for DNP-NMR spectroscopy #DNPNMR


Bridge12 is currently developing an integrated THz system for NMR-DNP spectroscopy. The basic idea is to operate the gyrotron inside the NMR magnet, just above the NMR probe head, effectively eliminating the need of a second superconducting magnet. This article is about a ferroshim insert that we had to develop for this purpose.


Ryan, H., J. van Bentum, and T. Maly, A ferromagnetic shim insert for NMR magnets – Towards an integrated gyrotron for DNP-NMR spectroscopy. J. Magn. Reson., 2017. 277: p. 1-7.


In recent years high-field Dynamic Nuclear Polarization (DNP) enhanced NMR spectroscopy has gained significant interest. In high-field DNP-NMR experiments (⩾400 MHz 1H NMR, ⩾9.4 T) often a stand-alone gyrotron is used to generate high microwave/THz power to produce sufficiently high microwave induced B1e fields at the position of the NMR sample. These devices typically require a second, stand-alone superconducting magnet to operate. Here we present the design and realization of a ferroshim insert, to create two iso-centers inside a commercially available wide-bore NMR magnet. This work is part of a larger project to integrate a gyrotron into NMR magnets, effectively eliminating the need for a second, stand-alone superconducting magnet.

Wednesday, March 8, 2017

Chapter Sixteen - Overhauser Dynamic Nuclear Polarization Studies on Local Water Dynamics #DNPNMR


Kaminker, I., R. Barnes, and S. Han, Chapter Sixteen - Overhauser Dynamic Nuclear Polarization Studies on Local Water Dynamics, in Methods in Enzymology, Z.Q. Peter and W. Kurt, Editors. 2015, Academic Press. p. 457-483.


Abstract Overhauser dynamic nuclear polarization (ODNP) is an emerging technique for quantifying translational water dynamics in the vicinity (1 nm) of stable radicals that can be chemically attached to macromolecules of interest. This has led to many in-depth and enlightening studies of hydration water of biomolecules, revolving around the role of solvent dynamics in the structure and function of proteins, nucleic acids, and lipid bilayer membranes. Still to date, a complete and fully automated ODNP instrument is not commercialized. The purpose of this chapter is to share the technical know-how of the hardware, theory, measurement, and data analysis method needed to successfully utilize and disseminate the ODNP technique.

Tuesday, March 7, 2017

[NMR] Joint postdoc position in biomoclecular NMR/DNP at IBS/INAC in Grenoble #DNPNMR

Joint Postdoctoral position available in biomolecular NMR and DNP in Grenoble (France)

In vitro and in vivo NMR investigation of the L,D-transpeptidase:peptidoglycan complex and of the mycobacterial cell-wall maturation

For over 50 years, peptidoglycan has played a pivotal role in the development of antibacterial chemotherapy, and essential peptidoglycan-synthesizing enzymes have been identified as antibacterial targets with high potential and characterized in vitro. Nevertheless the efforts to develop drugs acting on these rationally chosen targets have largely proven disappointing due to the limited number of biophysical tools capable to produce static and dynamic structural views of the entire peptidoglycan polymer along the bacterial cell-life cycle and of its evolution under the selective pressure of antibiotics. Focusing on one important cell-wall synthesis and maturation reaction, the L,D-transpeptidation, the present project aims at combining information obtained on samples of different levels of complexity, ranging from purified enzymes in interaction with peptidoglycan fragments to the complete cell-wall synthesis machinery in bacterial cells. In this context, innovative spectroscopic approaches including high-field solution NMR, solid-state NMR as well as MAS-DNP will be conducted to provide a new view on the role of L,D-transpeptidases (Ldts) in the cross-linking of peptidoglycan peptide stems along the cell maturation.

To succeed in this integrative approach a joint postdoctoral position is proposed between two NMR research groups in Grenoble that already collaborated efficiently in the past. Structural and dynamical studies of peptidoglycan:L,D-transpeptidase complexes by liquid- and solid-state NMR spectroscopy will be mainly hosted in the Biomolecular NMR Spectroscopy group at Institut de Biologie Structurale (IBS, http://www.ibs.fr/) in the team directed by Dr Jean-Pierre Simorre. This group has a direct access to the state of the art NMR facility at IBS containing six high-field spectrometers (950 MHz, 850 MHz, 700 MHz, 3x600 MHz) equipped with latest solid-state NMR and cryogenic liquid-state probes. Furthermore, an innovative approach based on MAS-DNP will be developed, in particular for in-vivo studies. This part of the work will take place in the DNP group of the Institute for Nanosciences and Cryogenics at CEA Grenoble under the supervision of Sabine Hediger. This team, directed by Gaël De Paëpe, hosts a 400 MHz MAS-DNP spectrometer and is very active on instrumentation and methods developments in standard and ultra-low temperature MAS-DNP. The synergy between both groups is reinforced by the geographical proximity.

Applicants are expected to have a doctoral experience in liquid-state and/or solid-state biomolecular NMR spectroscopy. Knowledge about MAS-DNP will be considered as a plus. The successful candidate will be recruited for 18 months and will benefit from an ANR postdoctoral fellowship. Interested candidates should send their application with a curriculum vitae, a letter of motivation, and 2 reference letters by May 31st, 2017 via email to Jean-Pierre Simorre (jean-pierre.simorre@ibs.fr) and Sabine Hediger (sabine.hediger@cea.fr).
-- 
_____________________________________________________________

Sabine Hediger
INAC/MEM/LRM
CEA Grenoble
17 rue des Martyrs
38054 Grenoble Cedex 9
France

Tel.: +33 4 38 78 65 79 
Fax : +33 4 38 78 50 90
_____________________________________________________________

====================================
This is the AMPERE MAGNETIC RESONANCE mailing list:


NMR web database:

Monday, March 6, 2017

[NMR] PhD position in DNP-NMR #DNPNMR



PhD position, Marseille (France)

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

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

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

Important: for eligibility and all relavant necessary information, please check: 



Contact: Armand MASION (masion@cerege.fr) or Stéphane VIEL (s.viel@univ-amu.fr)
Deadline for application: April 10th 2017, midnight (French Time) 

Best regards,

Stéphane Viel - Professeur des Universités - ICR Institut de Chimie Radicalaire (UMR CNRS 7273)

Aix-Marseille Université - Service 512 - St Jérôme - Avenue Escadrille Normandie Niemen - 13013 Marseille
Tél: +33(0)4 91 28 89 02 - Mobile : +33(0)6 68 27 29 01
Afin de respecter l'environnement, merci de n'imprimer cet email que si nécessaire.

====================================
This is the AMPERE MAGNETIC RESONANCE mailing list:

NMR web database:

Heteronuclear Cross-Relaxation under Solid-State Dynamic Nuclear Polarization #DNPNMR


Daube, D., et al., Heteronuclear Cross-Relaxation under Solid-State Dynamic Nuclear Polarization. J. Am. Chem. Soc., 2016. 138(51): p. 16572-16575.


We report on the spontaneous polarization transfer from dynamically hyperpolarized 1H to 13C during magic-angle spinning dynamic nuclear polarization (DNP) at temperatures around 100 K. The transfer is mediated by 1H–13C cross-relaxation within methyl groups due to reorientation dynamics, and results in an inverted 13C NMR signal of enhanced amplitude. Further spreading of transferred polarization can then occur via 13C–13C spin-diffusion. The resulting process is equal to the nuclear Overhauser effect (NOE) where typically continuous saturation of 1H by radio frequency irradiation is employed. Here, hyperpolarization by irradiation with microwaves in the presence of typical bis-nitroxide polarizing agents is utilized for steady-state displacement of 1H polarization from thermal equilibrium and perpetual spin-lattice relaxation. An effective 13C enhancement factor of up to −15 has been measured. Presence of Gd(III) furthermore amplifies the effect likely by accelerated relaxation of 1H. We provide experimental evidence for the proposed mechanism and show that DNP-induced cross-relaxation is a robust feature within proteins and single amino acids and discuss potential applications.

Sunday, March 5, 2017

[NMR] PhD & Postdoc in MAS-DNP at CEA Grenoble (France)

From the Ampere Magnetic Resonance List





PhDs & Postdocs in MAS-DNP at CEA Grenoble (France)

Contact Gaël De Paëpe (gael.depaepe@cea.fr)

PhD and Postdoc positions are now available at CEA-INAC (twinned with the Univ. Grenoble Alpes), France. The ERC-funded project will focus on the further development of an emerging hyperpolarization technique called MAS-DNP (Magic Angle Spinning Dynamic Nuclear Polarization). Combining hardware development, computational/theoretical approaches and sophisticated NMR experiments, we will apply the newly developed methodology to improve the understanding of challenging systems (both materials and biomolecules). More here: http://www.dnpgrenoble.net/.

Line of research / welcomed fields of expertize:
- Designing and conducting advanced DNP/NMR experiments
- Spin dynamics simulations for pulse sequence development
- Hardware development for cryogenic helium spinning (ULT-MAS)
- RF/MW engineering
- Quantum Chemical Calculations and Molecular Dynamics simulations
- Experience with material and/or biomolecular sample preparation
- Knowledge in radical chemistry
- Matlab programming
- EPR experiments


The funded project is part of a larger ongoing activity involving a strong partnership between our lab and LNCMI/CNRS (for high-field EPR) as well as an industrial partner (Bruker Biospin). Motivated candidates must have a good command (written / spoken) of English and should send a detailed CV and a letter of motivation, as well as any questions, to gael.depaepe@cea.fr.

Grenoble is one of the major cities in Europe for research with a large international scientific community. In addition, Grenoble has a large international student population, is a very pleasant city to live in, and is known as the “Capital of the Alps” with easy access to great skiing and hiking. It’s also only 2 hours’ drive to the Mediterranean Sea, Italy, or Switzerland. Grenoble, Lyon, and Geneva airports are nearby and permit straightforward international travel.

Recent selected references from the group:

1 – Solid-State NMR on Bacterial Cells: Selective Cell-Wall-Signal Enhancement and Resolution Improvement using Dynamic Nuclear Polarization, Takahashi H., Ayala I., Bardet M., De Paëpe G., Simorre J.P., Hediger S., Journal of the American Chemical Society, 135, 5105-5110, 2013

2 – Untangling the Condensation Network of Organosiloxanes on Nanoparticles using 2D 29Si- 29Si Solid-State NMR enhanced by Dynamic Nuclear Polarization, D Lee, G Monin, NT Duong, IZ Lopez, M Bardet, V Mareau, L Gonon, G. De Paëpe, Journal of the American Chemical Society, 136, 13781-13788, 2014

3 – Pushing NMR sensitivity limits using dynamic nuclear polarization with closed-loop cryogenic helium sample spinning, E. Bouleau, P. Saint-Bonnet, F. Mentink-Vigier, H. Takahashi, J.-F. Jacquot, M. Bardet, F. Aussenac, A. Purea, F. Engelke, S. Hediger, D. Lee, G. De Paëpe, Chemical Science, 6, 6806-6812, 2015

4 – A New Tool for NMR Crystallography: Complete 13C/15N Assignment of Organic Molecules at Natural Isotopic Abundance Using DNP-Enhanced Solid-state NMR, K. Märker, M. Pingret, Jean-Marie Mouesca, Didier Gasparutto, Sabine Hediger, Gaël De Paëpe, Journal of the American Chemical Society, 137, 13796-13799, 2015

5 - Welcoming natural isotopic abundance in solid-state NMR: probing pi-stacking and supramolecular structure of organic nanoassemblies using DNP, Märker K., Paul S., Lee D., Mouesca J.-M., Hediger S., De Paëpe G. Chemical Science, 8, 974, 2017

6 - Fast and accurate MAS-DNP simulations of large spin ensembles, Mentink-Vigier F., Vega S., De Paëpe G., Physical Chemistry Chemical Physics,19, 3506-3522, 2017

7 - Interfacial Ca2+ environments in nanocrystalline apatites revealed by DNP-enhanced 43Ca NMR spectroscopy, lee D., Leroy C., Crevant C., Bonhomme-Coury L., Babonneau F., Laurencin D., Bonhomme C., De Paëpe G., Nature communication, 8, 14104, 2017

--

Dr Gaël De Paëpe -- DRF/INAC/MEM/RM
INAC (CEA/Grenoble Alpes University)
17 Avenue des Martyrs
Bâtiment 51C
Office P.132a / Lab P.138
38054 Grenoble
Cedex 9 - France
email gael.depaepe@cea.fr
voice (office) +33 4 38 78 65 70
voice (lab) +33 4 38 78 47 26
fax +33 4 38 78 50 90

====================================
This is the AMPERE MAGNETIC RESONANCE mailing list:
http://www.drorlist.com/nmrlist.html

NMR web database:
http://www.drorlist.com/nmr.html

Friday, March 3, 2017

Singlet order conversion and parahydrogen-induced hyperpolarization of 13C nuclei in near-equivalent spin systems


Eills, J., et al., Singlet order conversion and parahydrogen-induced hyperpolarization of 13C nuclei in near-equivalent spin systems. J Magn Reson, 2017. 274: p. 163-172.


We have demonstrated two radiofrequency pulse methods which convert the nuclear singlet order of proton spin pairs into the magnetisation of nearby 13C nuclei. These irradiation schemes work well in the near-equivalence regime of the three-spin system, which applies when the difference in the two 1H-13C couplings is much smaller than the 1H-1H coupling. We use pulse sequences to generate thermally polarized singlet states in a reproducible manner, and study the singlet-to-magnetisation transfer step. Preliminary results demonstrate a parahydrogen-enhanced 13C polarization level of at least 9%, providing a signal enhancement factor of more than 9000, using 50% enriched parahydrogen.

Wednesday, March 1, 2017

Spatial distribution of organic functional groups supported on mesoporous silica nanoparticles: a study by conventional and DNP-enhanced 29Si solid-state NMR #DNPNMR


Kobayashi, T., et al., Spatial distribution of organic functional groups supported on mesoporous silica nanoparticles: a study by conventional and DNP-enhanced 29Si solid-state NMR. Phys. Chem. Chem. Phys., 2017. 19(3): p. 1781-1789.


Solid-state NMR spectroscopy, both conventional and dynamic nuclear polarization (DNP)-enhanced, was employed to study the spatial distribution of organic functional groups attached to the surface of mesoporous silica nanoparticles via co-condensation and grafting. The most revealing information was provided by DNP-enhanced two-dimensional 29Si-29Si correlation measurements, which unambiguously showed that post-synthesis grafting leads to a more homogeneous dispersion of propyl and mercaptopropyl functionalities than co-condensation. During the anhydrous grafting process, the organosilane precursors do not self-condense and are unlikely to bond to the silica surface in close proximity (less than 4 A) due to the limited availability of suitably arranged hydroxyl groups.

[NMR] Post-doctoral position in Rossini lab at Iowa State University

From the Ampere Magnetic Resonance List


Dear Dror, 

Could you please forward this advertisement about a post-doctoral fellow opening in my lab to the members of the NMR mailing list: 

***********

A post-doctoral fellow position is immediately available in the research group of Professor Aaron Rossini at Iowa State University. The goal of the project is to develop new solid-state NMR methods for the characterization of pure and formulated active pharmaceutical ingredients (APIs). We will accomplish this by utilizing the state of the art NMR technologies of fast MAS and dynamic nuclear polarization (DNP) to enhance the sensitivity of solid-state NMR experiments on APIs. The projects will be executed in collaboration with Dr. Joe Lubach and Dr. Karthik Nagapudi (Genentech). The solid-state NMR facilities at ISU are excellent and include Bruker 400 MHz, 600 MHz and 800 MHz spectrometers. We also have routine access to a 263 GHz/400 MHz Bruker DNP solid-state NMR spectrometer which is located in the adjacent DOE Ames laboratory. The requirements are a PhD. in chemistry, physics or materials science, prior experience with solid-state NMR spectroscopy and good written and spoken english. Prior experience with quantum chemical calculations of NMR properties, numerical simulations of solid-state NMR experiments and other characterization techniques such as X-ray diffraction are also assets. Interested candidates should send a CV including the contact information for at least one reference to arossini@iastate.edu.


Representative Publications:

(1) Hirsh, D. A.; Rossini, A. J.; Emsley, L.; Schurko, R. W. Phys. Chem. Chem. Phys. 2016, 18, 25893-25904.
(2) Pinon, A. C.; Rossini, A. J.; Widdifield, C. M.; Gajan, D.; Emsley, L. Mol. Pharm. 2015, 12, 4146-4153.
(3) Rossini, A. J.; Emsley, L.; O'Dell, L. A. Phys. Chem. Chem. Phys. 2014, 16, 12890-12899.
(4) Rossini, A. J.; Widdifield, C. M.; Zagdoun, A.; Lelli, M.; Schwarzwälder, M.; Copéret, C.; Lesage, A.; Emsley, L. J. Am. Chem. Soc. 2014, 136, 2324-2334.
(5) Rossini, A. J.; Zagdoun, A.; Hegner, F. S.; Schwarzwälder, M.; Gajan, D.; Copéret, C.; Lesage, A.; Emsley, L. J. Am. Chem. Soc. 2012, 134, 16899−16908.

More information about our lab can be found at: https://rossini.chem.iastate.edu/

************
Thank you in advance,
Aaron Rossini,
Assistant Professor
Department of Chemistry
Iowa State University
0205 Hach Hall
2438 Pammel Drive
Ames, IA 50011-3111
515-294-8952

====================================
This is the AMPERE MAGNETIC RESONANCE mailing list:

NMR web database: