Wednesday, February 28, 2018

Analysis of Molecular Orientation in Organic Semiconducting Thin Films Using Static Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy #DNPNMR

Suzuki, K., et al., Analysis of Molecular Orientation in Organic Semiconducting Thin Films Using Static Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy. Angew. Chem. Int. Ed., 2017. 56(47): p. 14842-14846.


Molecular orientation in amorphous organic semiconducting thin-film devices is an important issue affecting device performance. However, to date it has not been possible to analyze the “distribution” of the orientations. Although solid-state NMR (ssNMR) spectroscopy can provide information on the “distribution” of molecular orientations, the technique is limited because of the small amount of sample in the device and the low sensitivity of ssNMR. Here, we report the first application of dynamic nuclear polarization enhanced ssNMR (DNP-ssNMR) spectroscopy for the orientational analysis of amorphous phenyldi(pyren-1-yl)phosphine oxide (POPy2). The 31P DNP-ssNMR spectra exhibited a sufficient signal-to-noise ratio to quantify the distribution of molecular orientations in amorphous films: the P=O axis of the vacuum-deposited and drop-cast POPy2 shows anisotropic and isotropic distribution, respectively. The different molecular orientations reflect the molecular origin of the different charge transport behaviors.

Tuesday, February 27, 2018

[NMR] POSTDOCTORAL POSITION: Nuclear Spin Singlet States and PHIP, New York University



POSTDOCTORAL POSITION: Nuclear Spin Singlet States and PHIP
New York University

DESCRIPTION:

A postdoctoral position is available immediately for the study of nuclear spin singlet state life times and singlet relaxation mechanisms, the development of efficient singlet/triplet conversion pulse sequences and methodology, as well as para-hydrogen induced polarization (PHIP) in the laboratory of Alexej Jerschow at New York University (NYU). The lab is located in newly renovated facilities of the Molecular Nanoscience Center at NYU’s Washington Square Campus in the heart of Manhattan.

Applicants should have an advanced degree (Ph.D) in Physics, Chemistry, or a related field, and should have experience with NMR/MRI theory and experiment. Knowledge of relaxation theory and computer programming and simulation skills would be a plus, as well as prior experience any of the specific research areas. Remuneration is competitive and commensurate with experience and will be based on New York University guidelines. Women and minorities are encouraged to apply.

CONTACT: 
To be considered, the application has to be submitted via the following link: https://apply.interfolio.com/49106.

Preliminary inquiries can be sent to
Alexej Jerschow
Department of Chemistry
100 Washington Square East
New York University
New York, NY 10003.

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Monday, February 26, 2018

Best Practices for Scientific Computing

Ever since I started in Magnetic Resonance Spectroscopy I did a lot of programming in Matlab, C, C++, LabVIEW, html,  and more recently Python. All of it is picked along the way, without ever having a class in programming. With that a lot of bad habits evolve over the years. No matter what programming language is your currently choice, take a look at this very nice article. If you don't want to read through the whole thing take a look at Box 1 on page 2 to get an idea of the basics.



Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, et al. (2014) Best Practices for Scientific Computing. PLoS Biol 12(1): e1001745. https://doi.org/10.1371/journal.pbio.1001745


Scientists spend an increasing amount of time building and using software. However, most scientists are never taught how to do this efficiently. As a result, many are unaware of tools and practices that would allow them to write more reliable and maintainable code with less effort. We describe a set of best practices for scientific software development that have solid foundations in research and experience, and that improve scientists' productivity and the reliability of their software.

High-resolution hyperpolarized metabolic imaging of the rat heart using k-t PCA and k-t SPARSE

Wespi, P., et al., High-resolution hyperpolarized metabolic imaging of the rat heart using k-t PCA and k-t SPARSE. NMR Biomed, 2018. 31(2): p. e3876-n/a.


The purpose of this work was to increase the resolution of hyperpolarized metabolic imaging of the rat heart with accelerated imaging using k–t principal component analysis (k–t PCA) and k–t compressed sensing (k–t SPARSE). Fully sampled in vivo datasets were acquired from six healthy rats after the injection of hyperpolarized [1-13C]pyruvate. Data were retrospectively undersampled and reconstructed with either k–t PCA or k–t SPARSE. Errors of signal–time curves of pyruvate, lactate and bicarbonate were determined to compare the two reconstruction algorithms for different undersampling factors R. Prospectively undersampled imaging at 1 × 1 × 3.5-mm3 resolution was performed with both methods in the same animals and compared with the fully sampled acquisition. k–t SPARSE was found to perform better at R < 3, but was outperformed by k–t PCA at R ≥ 4. Prospectively undersampled data were successfully reconstructed with both k–t PCA and k–t SPARSE in all subjects. No significant difference between the undersampled and fully sampled data was found in terms of signal-to-noise ratio (SNR) performance and metabolic quantification. Accelerated imaging with both k–t PCA and k–t SPARSE allows an increase in resolution, thereby reducing the intravoxel dephasing of hyperpolarized metabolic imaging of the rat heart.

[NMR] PhD position on solid-state NMR of materials at the University of Lille, France #DNPNMR



Please forward to potential candidates.

Project title: Development of high-field (DNP)-NMR methods for the observation of quadrupolar nuclei in hybrid materials.

A three-year PhD position in solid-state NMR spectroscopy of advanced materials is available at the University of Lille, Lille, France. It can start from July 2018.

Project description: Hybrid materials are promising for numerous applications, such as catalysis, gas storage or drug delivery. Solid-state NMR provides unique information about the atomic-level structure of defects and surfaces in hybrid materials. Nevertheless, a major limitation is the lack of sensitivity of solid-state NMR, which limits the observation of defects and surfaces, particularly for insensitive isotopes with low gyromagnetic ratio, low natural abundance or subject to large quadrupolar interaction. Recent instrumental developments, such as high-magnetic field and Dynamic Nuclear Polarization (DNP), can boost the sensitivity of solid-state NMR. This project aims at developing and applying novel solid-state NMR methods to probe the local environment of quadrupolar nuclei in hybrid materials. The structural information obtained by solid-state NMR will be useful to improve the performances of hybrid materials.

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

The person: We seek application from national and international students who have graduated in physics or chemistry, preferably with a background in material sciences or NMR spectroscopy. The successful applicant will be given the opportunity to work in an exciting environment with national and international collaborations.

Contact: Applications and informal queries about the lab and research projects should be directed by email to olivier.lafon@univ-lille1.fr

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Friday, February 23, 2018

Optimal sample formulations for DNP SENS: The importance of radical-surface interactions #DNPNMR

Perras, F.A., et al., Optimal sample formulations for DNP SENS: The importance of radical-surface interactions. Current Opinion in Colloid & Interface Science, 2018. 33: p. 9-18.


The efficacy of dynamic nuclear polarization (DNP) surface-enhanced NMR spectroscopy (SENS) is reviewed for alumina, silica, and ordered mesoporous carbon (OMC) materials, with vastly different surface areas, as a function of the biradical concentration. Importantly, our studies show that the use of a “one-size-fits-all” biradical concentration should be avoided when performing DNP SENS experiments and instead an optimal concentration should be selected as appropriate for the type of material studied as well as its surface area. In general, materials with greater surface areas require higher radical concentrations for best possible DNP performance. This result is explained with the use of a thermodynamic model wherein radical-surface interactions are expected to lead to an increase in the local concentration of the polarizing agent at the surface. We also show, using plane-wave density functional theory calculations, that weak radical-surface interactions are the cause of the poor performance of DNP SENS for carbonaceous materials.

Wednesday, February 21, 2018

A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers #DNPNMR

Gyrotrons typically generate much more microwave power than needed in a DNP-NMR experiment. This article describes a very nice way how to share the microwave power generated by a single gyrotron between two NMR experiments.


Dubroca, T., et al., A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers. J. Magn. Reson., 2018.


Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T (1H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110K, while a 31P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T (1H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 µL, i.e. 3 mm diameter NMR tubes).

Tuesday, February 20, 2018

[NMR] AMPERE NMR SCHOOL 2018

Dear NMR Community, 

On behalf of the Organizing Committee it’s my great pleasure to invite you to attend the next AMPERE NMR School 2018, an annual event organized since earlier 90th in Zakopane under auspices of the Groupment AMPERE, will be organized from June 10 th to 16 th 2018 in Zakopane, Poland ( www. zakopane .pl). 

The traditional topics given in the School: 
· solid state and soft matter NMR
· NMR diffusometry and relaxometry
· application of NMR in biology and medicine
· magnetic resonance imaging and spectroscopy
· NMR and quantum information
· theoretical and experimental aspects of dynamic nuclear spin polarization
· NMR methodology and techniques.

The School is addressed to PhD students of various fields of physics, chemistry, biology and medicine and is focused on theoretical and experimental aspects of NMR methods and their applications. The lectures are expected to contain a basic (tutorial) introduction and the research of your interest. 

The conference fee (450 Euro) includes full board, accommodation and the conference proceedings. We will be able to provide a financial support for the students you will recommend up to 200 Euro. More detailed information you will find on the conference website. 




With my best wishes

Stefan Jurga

……………………………………………………..
Prof. Stefan Jurga
Director
NanoBioMedical Centre
Adam Mickiewicz University
Ul. Umultowska 85
61-614 Poznań, Poland
Ph. +48 61 829 67 04

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[NMR] Open NMR Position at MPI Kohlenforschung in Mülheim an der Ruhr

A new position in the area NMR applied to catalysis research is now open in Mülheim an der Ruhr, Germany. Please distribute. (Basic German knowledge required ;)


---------------------------------------------------
Christophe Farès, Ph.D.
---------------------------------------------------
NMR Department/NMR Abteilung
Max-Planck Insitut für Kohlenforschung/ Max-Planck Insitute for Coal Research
Kaiser-Wilhelm Platz 1
45470 Mülheim an der Ruhr
Tel: +49 208 306 2130 
E-mail: fares [a] mpi-muelheim [.] mpg [.] de
---------------------------------------------------

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Monday, February 19, 2018

Sensitivity-enhanced detection of non-labile proton and carbon NMR spectra on water resonances #DNPNMR

Novakovic, M., et al., Sensitivity-enhanced detection of non-labile proton and carbon NMR spectra on water resonances. Phys. Chem. Chem. Phys., 2017. 20(1): p. 56-62.


Chemical exchange saturation transfer (CEST) experiments enhance the NMR signals of labile protons by continuously transferring these protons' saturation to an abundant solvent pool like water. The present study expands these principles by fusing into these experiments homonuclear isotropic mixing sequences, enabling the water-enhanced detection of non-exchangeable species. Further opportunities are opened by the addition of coupling-mediated heteronuclear polarization transfers, which then impose on the water resonance a saturation stemming from non-labile heteronuclear species like (13)C. To multiplex the ensuing experiments, these relayed approaches are combined with time-domain schemes involving multiple Ramsey-labeling experiments imparting the frequencies of the non-labile sites on the water resonance, via chemical exchange. (13)C and (1)H NMR spectra were detected in this fashion with about two-fold SNR amplification vis-a-vis conventionally detected spectroscopies. When combined with non-uniform sampling principles, this methodology thus becomes a sensitive alternative to detect non-exchangeable species in biomolecules. Still, multiple parameters including the scalar couplings and solvent exchange rates, will affect the efficiency and consequently the practicality of the overall experiment.

Friday, February 16, 2018

NMR Signal Quenching from Bound Biradical Affinity Reagents in DNP Samples #DNPNMR #NMR


Rogawski, R., et al., NMR Signal Quenching from Bound Biradical Affinity Reagents in DNP Samples. J Phys Chem B, 2017. 121(48): p. 10770-10781.


We characterize the effect of specifically bound biradicals on the NMR spectra of dihydrofolate reductase from E. coli. Dynamic nuclear polarization methods enhance the signal-to-noise of solid state NMR experiments by transferring polarization from unpaired electrons of biradicals to nuclei. There has been recent interest in colocalizing the paramagnetic polarizing agents with the analyte of interest through covalent or noncovalent specific interactions. This experimental approach broadens the scope of dynamic nuclear polarization methods by offering the possibility of selective signal enhancements and the potential to work in a broad range of environments. Paramagnetic compounds can have other effects on the NMR spectroscopy of nearby nuclei, including broadening of nuclear resonances due to the proximity of the paramagnetic agent. Understanding the distance dependence of these interactions is important for the success of the technique. Here we explore paramagnetic signal quenching due to a bound biradical, specifically a biradical-derivatized trimethoprim ligand of E. coli dihydrofolate reductase. Biradical-derivatized trimethoprim has nanomolar affinity for its target, and affords strong and selective signal enhancements in dynamic nuclear polarization experiments. In this work, we show that, although the trimethoprim fragment is well ordered, the biradical (TOTAPOL) moiety is disordered when bound to the protein. The distance dependence in bleaching of NMR signal intensity allows us to detect numerous NMR signals in the protein. We present the possibility that static disorder and electron spin diffusion play roles in this observation, among other contributions. The fact that the majority of signals are observed strengthens the case for the use of high affinity or covalent radicals in dynamic nuclear polarization solid state NMR enhancement.

[NMR] PhD position at the CNRS/University of Marseille #DNPNMR


ERC-funded PhD position is available in Marseille on the structural investigation of functional organic materials by DNP and NMR

Project title: “Structural investigation of polymorphic organic powders at natural isotopic abundance”

A 3-year PhD position is available at the CNRS/University of Aix-Marseille on the development of new experimental and theoretical approaches in dynamic nuclear polarization (DNP) NMR for the structural investigation of functional organic powders at natural isotopic abundance.

Context: Functional organic materials have been successfully used as active components in many applications, going from light emitters to optical devices, flexible photovoltaic devices, printed electronic inks, molecular machines, pigments, pharmaceuticals, etc. Such compounds can be used to produce low-cost, easily manufacturable, and lightweight materials that can replace traditional inorganic functional materials in energy-related applications (e.g. as semiconductors in solar cells or light emitter diodes), bringing significant economic and practical benefits. Moreover, they can be easily chemically modified to respond to specific application requirements (e.g. as active principle ingredients in pharmacy). In view of obtaining new functional materials with tailored properties, the true challenge in this field is the ability to establish a clear two-way relationship between the structure and the properties of the functional material in its end-use solid form. Because, in their end-use form, materials for the mentioned applications generally form particles with nanometer to micrometer-size dimensions, the main actual limitation to the rational development of new functional materials is the lack of a widely applicable methodology able to characterize fully and unambiguously the structure of functional organic powders lacking long-range order. 

Aim and job description: The aim of the thesis is to devise new analytical routes for accessing ab initio the structure of polymorphic organic microcrystalline powders at natural isotopic abundance through a combination of DNP NMR experiments and computational methods. The selected candidate will actively develop and optimize new NMR experiments for accessing dipolar and scalar couplings on functional materials for energy or pharmaceutical applications at natural isotopic abundance. The candidate will also use first principle calculations of NMR observables (in collaboration with the University of Oxford), as well as analytical (Mathematica, MatLab) or numerical (SIMPSON) simulations to help interpretation of experimental data.

Practical details: The PhD project will be performed at the Institut de Chimie Radicalaire (ICR UMR7273). Located in the south of France in Marseille, ICR is internationally recognized for its double expertise in i) the development of new DNP approaches for the characterization of organic solids and ii) the synthesis of radical species currently used as the most effective polarizing agents for solid DNP. Through the analytical facility Spectropole, ICR has access to a vast range of instrumentation for X-ray diffraction, mass spectrometry, IR, elemental analysis, as well as several NMR spectrometers for liquids and solids with fields ranging from 300 to 600 MHz. Notably, the candidate will access two 400 MHz wide-bore NMR spectrometers equipped with the latest hardware and numerous solid-state probes for spinning speeds up to 60 kHz. 

The PhD studentship will be funded by a European contract (ERC Starting grant, STRUCTURE project, G. Mollica) for a duration of 3 years, starting October 1st 2018. In the framework of ongoing collaborations, the candidate will be in contact with researchers from other European groups. He/she is expected to communicate the results of his/her work at international conferences.



Profile: The candidate should have a Master degree in Chemistry or Physics. Previous experience in NMR spectroscopy and/or computational methods is an advantage. Skills in organic chemistry are not required, but experience with crystallization procedures will be a plus. He/she is expected to be a motivated, imaginative, independent hard worker, with an interest in understanding fundamental aspects of NMR and polymorphism. He/she should have no issues with mobility and demonstrate excellent communication skills in English (knowledge of French is not required).

Application procedure: The candidate should send a motivation letter, at least two names for recommendation, CV (with list of publications and communications) and Master grades (with ranking) to:


&

Stephane Viel s.viel@univ-amu.fr

Application deadline: 15th March 2018.
--------------------------------


(EURAXESS Job Offer id: 279201)
--------------------------------


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Wednesday, February 14, 2018

Photo-induced radical polarization and liquid-state dynamic nuclear polarization using fullerene nitroxide derivatives #DNPNMR


Liu, G., et al., Photo-induced radical polarization and liquid-state dynamic nuclear polarization using fullerene nitroxide derivatives. Phys. Chem. Chem. Phys., 2017. 19(47): p. 31823-31829.


We report on radical polarization and optically-driven liquid DNP using nitroxide radicals functionalized by photoexcitable fullerene derivatives. Pulse laser excitation of the fullerene moiety leads to transient nitroxide radical polarization that is one order of magnitude larger than that at the Boltzmann equilibrium. The life time of the radical polarization increases with the size of the fullerene derivative and is correlated with the electronic spin-lattice relaxation time T1e. Overhauser NMR signal enhancements of toluene solvent protons were observed under steady-state illumination, which replaced microwave irradiation.

Tuesday, February 13, 2018

[NMR] PhD position

From the Ampere Magnetic Resonance List



Dear colleagues
we would like to advertise the following position for a PhD candidate in physics at TU Dortmund.
Please forward it to any suitable candidate.
Thanks!
Dieter

Optically Detected Magnetic Resonance Imaging of Direct Band-Gap Solar Cell Materials

In this research project, we will develop two complementary techniques for studying semiconductor materials with direct band gaps. This will lead to an improved understanding of processes that limit the efficiency of solar cell materials and may, in the long run, contribute to the development of better solar cells with higher efficiency. The techniques are based on magnetic resonance (electron-spin and nuclear-spin magnetic resonance) but use optical pumping for enhancing the spin polarization and optical detection for increasing the sensitivity and allow spatial localization. Ot achieve spatial resolution, we will use spatial encoding via the Larmor frequency on the basis of pulsed magnetic field gradients. We envision that this project will contribute towards the long-term goal of economical and eco-friendly devices that harvest solar energy at the highest possible efficiency. Earlier results from this project are available at https://e3.physik.tu-dortmund.de/~suter/research/OEMR_Semiconductors.pdf.
The ideal candidate for this position has a solid background in optical spectroscopy and / or magnetic resonance, a high motivation for realising advanced experimental techniques and a keen interest in the properties of high-quality semiconductor materials. For additional information or to apply send email to Dieter.Suter@tu-dortmund.de

____________________________________________________________________________
Dieter Suter | Tel: (+49 231) 755 3512
Fakultät Physik | Fax: (+49 231) 755 3509
Technische Universität Dortmund |
D-44221 Dortmund | e-mail: Dieter.Suter@tu-dortmund.de
____________________________________________________________________________

Monday, February 12, 2018

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

Most commonly nitroxide-based radicals are used in DNP. However, there are many other stable radicals. This one is a UV generated radical that is stable for weeks at room temperature. In addition it exhibits a fairly narrow linewidth. This radical, in combination with another narrow line radical (BDPA, trityl, etc.) could make a very efficient polarizing agent when mixed together or even covalently attached to each other.



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


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

Friday, February 9, 2018

Three-Dimensional Structure Determination of Surface Sites #DNPNMR #NMR


Berruyer, P., et al., Three-Dimensional Structure Determination of Surface Sites. J Am Chem Soc, 2017. 139(2): p. 849-855.


The spatial arrangement of atoms is directly linked to chemical function. A fundamental challenge in surface chemistry and catalysis relates to the determination of three-dimensional structures with atomic-level precision. Here we determine the three-dimensional structure of an organometallic complex on an amorphous silica surface using solid-state NMR measurements, enabled through a dynamic nuclear polarization surface enhanced NMR spectroscopy approach that induces a 200-fold increase in the NMR sensitivity for the surface species. The result, in combination with EXAFS, is a detailed structure for the surface complex determined with a precision of 0.7 A. We observe a single well-defined conformation that is folded toward the surface in such a way as to include an interaction between the platinum metal center and the surface oxygen atoms.

Monday, February 5, 2018

Direct enhancement of nitrogen-15 targets at high-field by fast ADAPT-SABRE


Roy, S.S., et al., Direct enhancement of nitrogen-15 targets at high-field by fast ADAPT-SABRE. J. Magn. Reson., 2017. 285: p. 55-60.


Signal Amplification by Reversible Exchange (SABRE) is an attractive nuclear spin hyperpolarization technique capable of huge sensitivity enhancement in nuclear magnetic resonance (NMR) detection. The resonance condition of SABRE hyperpolarization depends on coherent spin mixing, which can be achieved naturally at a low magnetic field. The optimum transfer field to spin-1/2 heteronuclei is technically demanding, as it requires field strengths weaker than the earth’s magnetic field for efficient spin mixing. In this paper, we illustrate an approach to achieve strong 15N SABRE hyperpolarization at high magnetic field by a radio frequency (RF) driven coherent transfer mechanism based on alternate pulsing and delay to achieve polarization transfer. The presented scheme is found to be highly robust and much faster than existing related methods, producing ∼3 orders of magnitude 15N signal enhancement within 2 s of RF pulsing.

Friday, February 2, 2018

[NMR] HYP18 conference Sep 2-5 2018, Southampton UK #DNPNMR #NMR

The HYP18 conference on hyperpolarization is now open for registration and abstract submission at hyp18.com.


This conference will cover the main areas of nuclear hyperpolarization and some other methods for sensitivity enhancement in NMR and MRI, including:

several variants of dynamic nuclear polarization (DNP) 
optical pumping 
quantum-rotor-induced polarization 
parahydrogen-induced polarization 
diamond magnetometry 

and key applications such as clinical imaging, materials science, and molecular structure determination.


The confirmed plenary speakers are:
Kevin Brindle, Cambridge, UK
Bob Griffin, MIT, USA
Sami Jannin, ENS Lyon, France
Fedor Jelezko, Ulm, Germany
John Kurhanewicz, San Francisco, California, USA
Anne Lesage, ENS Lyon, France
Leif Schröder, Berlin, Germany
Thomas Theis, Durham, North Carolina, USA


The confirmed invited speakers are:
Stephan Appelt, Aachen, Germany
Peter Blümler, Mainz, Germany
Arnaud Comment, Cambridge, UK
Meghan Halse, York, UK
Mathilde Lerche, Copenhagen, Denmark
Gaël de Paëpe, Grenoble, France
Marek Pruski, Iowa, USA
Welcome to Southampton in September!
Malcolm and Peppe



——————————————————
HYP18
Hyperpolarized Magnetic Resonance
Southampton UK, Sep 2-5 2018
——————————————————
Prof Malcolm Levitt
School of Chemistry
Room 27:2026
University of Southampton
Southampton SO17 1BJ
England.
tel. +44 23 8059 6753
fax: +44 23 8059 3781
iPhone: +44 77 7078 2024
*******************************************


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A highly versatile automatized setup for quantitative measurements of PHIP enhancements #SABRE #NMR


Kiryutin, A.S., et al., A highly versatile automatized setup for quantitative measurements of PHIP enhancements. J. Magn. Reson., 2017. 285: p. 26-36.


The design and application of a versatile and inexpensive experimental extension to NMR spectrometers is described that allows to carry out highly reproducible PHIP experiments directly in the NMR sample tube, i.e. under PASADENA condition, followed by the detection of the NMR spectra of hyperpolarized products with high spectral resolution. Employing this high resolution it is feasible to study kinetic processes in the solution with high accuracy. As a practical example the dissolution of hydrogen gas in the liquid and the PHIP kinetics during the hydrogenation reaction of Fmoc-O-propargyl-l-tyrosine in acetone-d6 are monitored. The timing of the setup is fully controlled by the pulse-programmer of the NMR spectrometer. By flushing with an inert gas it is possible to efficiently quench the hydrogenation reaction in a controlled fashion and to detect the relaxation of hyperpolarization without a background reaction. The proposed design makes it possible to carry out PHIP experiments in an automatic mode and reliably determine the enhancement of polarized signals.

Thursday, February 1, 2018

Pulsed Dynamic Nuclear Polarization with Trityl Radicals #DNPNMR


Mathies, G., et al., Pulsed Dynamic Nuclear Polarization with Trityl Radicals. The Journal of Physical Chemistry Letters, 2016. 7(1): p. 111-116.


Continuous-wave (CW) dynamic nuclear polarization (DNP) is now established as a method of choice to enhance the sensitivity in a variety of NMR experiments. Nevertheless, there remains a need for the development of more efficient methods to transfer polarization from electrons to nuclei. Of particular interest are pulsed DNP methods because they enable a rapid and efficient polarization transfer that, in contrast with CW DNP methods, is not attenuated at high magnetic fields. Here we report nuclear spin orientation via electron spin-locking (NOVEL) experiments using the polarizing agent trityl OX063 in glycerol/water at a temperature of 80 K and a magnetic field of 0.34 T. (1)H NMR signal enhancements up to 430 are observed, and the buildup of the local polarization occurs in a few hundred nanoseconds. Thus, NOVEL can efficiently dynamically polarize (1)H atoms in a system that is of general interest to the solid-state DNP NMR community. This is a first, important step toward the general application of pulsed DNP at higher fields.