Monday, July 30, 2018

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

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



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

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

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

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

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

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


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

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

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

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



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

NMR web database:

Monday, July 23, 2018

[NMR] Research Fellow position at the University of Southampton

Research Fellow position at the University of Southampton, UK

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

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

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

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

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

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

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

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

Dr. Giuseppe Pileio, PhD

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

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

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

NMR web database:

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

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


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

Friday, July 20, 2018

Quantum-rotor-induced polarization

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


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

Wednesday, July 18, 2018

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

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


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

Monday, July 16, 2018

Stable Isotope-Resolved Analysis with Quantitative Dissolution Dynamic Nuclear Polarization

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


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

Friday, July 13, 2018

Reversal of Paramagnetic Effects by Electron Spin Saturation #DNPNMR

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


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

Wednesday, July 11, 2018

Hyperpolarized NMR: d-DNP, PHIP, and SABRE

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


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

Monday, July 9, 2018

Applications of dissolution dynamic nuclear polarization in chemistry and biochemistry

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


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

Friday, July 6, 2018

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

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


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

Wednesday, July 4, 2018

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

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


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

Tuesday, July 3, 2018


Postdoctoral Position:

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

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

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

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

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

Morgan Fitch, Administrative Support Assistant

National High Magnetic Field Laboratory

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

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

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

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

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

Monday, July 2, 2018

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

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


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