Friday, December 30, 2016

Dissolution dynamic nuclear polarization–enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions #DNPNMR


Lee, Y., Dissolution dynamic nuclear polarization–enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions. Applied Spectroscopy Reviews, 2015. 51(3): p. 210-226.


Hyperpolarization techniques, in particular dissolution dynamic nuclear polarization (D-DNP), make a contribution to overcoming sensitivity limitations of magnetic resonance (MR) spectroscopy through signal enhancement, leading to the study of new fields of research in real time. Utilizing the large signal enhancement initially produced on small molecules, it has become possible to study systems with low gamma-nuclei, such as 13C, 15N, and 29Si. This review summarizes recent studies that have extended the applicability of D-DNP into various areas of research, especially for systems in nonequilibrium conditions that involve in vivo metabolic/molecular MR imaging for early stage disease diagnosis and real-time MR analysis of various chemical/biochemical reactions for kinetic and mechanistic studies. This review also deals with the theoretical aspects of DNP mechanisms and experimental arrangements of the dissolution setup.

Wednesday, December 28, 2016

Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy #DNPNMR


Nagaraj, M., et al., Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy. Chembiochem, 2016. 17(14): p. 1308-11.


Dynamic nuclear polarization (DNP) NMR can enhance sensitivity but often comes at the price of a substantial loss of resolution. Two major factors affect spectral quality: low-temperature heterogeneous line broadening and paramagnetic relaxation enhancement (PRE) effects. Investigations by NMR spectroscopy, isothermal titration calorimetry (ITC), and EPR revealed a new substantial affinity of TOTAPOL to amyloid surfaces, very similar to that shown by the fluorescent dye thioflavin-T (ThT). As a consequence, DNP spectra with remarkably good resolution and still reasonable enhancement could be obtained at very low TOTAPOL concentrations, typically 400 times lower than commonly employed. These spectra yielded several long-range constraints that were difficult to obtain without DNP. Our findings open up new strategies for structural studies with DNP NMR spectroscopy on amyloids that can bind the biradical with affinity similar to that shown towards ThT.

[NMR] Tenure-track NMR position at UCSD

From the Ampere Magnetic Resonance List



Tenure-track NMR position at UCSD

THE DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY within the Division of Physical Sciences at UC San Diego (http://chemistry.ucsd.edu/) invites applications for the position of tenure-track Assistant Professor in Chemistry & Biochemistry, broadly defined. Candidates with research interests in Biological, Materials, or Chemical NMR Spectroscopy are particularly encouraged to apply, especially experimentalists with a strong focus on addressing fundamental structural questions about macromolecules and supramolecular assemblies using the most up-to-date NMR methods. Applications to biomolecules and their complexes, novel materials and assemblies, nanoparticles, and surfaces and interfaces are all of interest. Candidates must have a Ph.D. in chemistry, biophysics or a closely related field and a demonstrated ability or potential for a recognized program of excellence in both teaching and research. All positions are subject to budget approval.

The Department of Chemistry and Biochemistry at UC San Diego is committed to academic excellence and diversity within the faculty, staff and student body. Successful candidates will be judged on research and teaching accomplishments, as well as on potential and/or demonstrated leadership in areas contributing to diversity, equity, and inclusion. Successful candidates will be expected to teach chemistry and/or biochemistry courses at both the graduate and undergraduate levels.

Candidates should submit online: Curriculum vitae with list of publications, reprints of up to five representative papers, a statement of teaching, and a personal statement that includes a summary of research plans. Additionally, a separate statement that addresses past and/or potential contributions to diversity, equity and inclusion should also be included in the application materials, see http://facultyequity.ucsd.edu/Faculty-Applicant-C2D-Info.asp.

Candidates should also provide the names and contact information for at least three references who can address the candidate’s research, teaching, and professional service.


Salary is commensurate with qualifications and based on University of California pay scale.

Review of applications will commence on February 1, 2017, and continue until the position is filled.

UCSD is an Affirmative Action/Equal Opportunity Employer with a strong institutional commitment to excellence through diversity.

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Friday, December 23, 2016

Atomistic Description of Reaction Intermediates for Supported Metathesis Catalysts Enabled by DNP SENS #DNPNMR


Ong, T.C., et al., Atomistic Description of Reaction Intermediates for Supported Metathesis Catalysts Enabled by DNP SENS. Angew Chem Int Ed Engl, 2016. 55(15): p. 4743-7.


Obtaining detailed structural information of reaction intermediates remains a key challenge in heterogeneous catalysis because of the amorphous nature of the support and/or the support interface that prohibits the use of diffraction-based techniques. Combining isotopic labeling and dynamic nuclear polarization (DNP) increases the sensitivity of surface enhanced solid-state NMR spectroscopy (SENS) towards surface species in heterogeneous alkene metathesis catalysts; this in turn allows direct determination of the bond connectivity and measurement of the carbon-carbon bond distance in metallacycles, which are the cycloaddition intermediates in the alkene metathesis catalytic cycle. Furthermore, this approach makes possible the understanding of the slow initiation and deactivation steps in these heterogeneous metathesis catalysts.

Wednesday, December 21, 2016

Dynamic Nuclear Polarization and Other Magnetic Ideas at EPFL #DNPNMR


Bornet, A., et al., Dynamic Nuclear Polarization and Other Magnetic Ideas at EPFL. CHIMIA International Journal for Chemistry, 2012. 66(10): p. 734-740.


Although nuclear magnetic resonance (NMR) can provide a wealth of information, it often suffers from a lack of sensitivity. Dynamic Nuclear Polarization (DNP) provides a way to increase the polarization and hence the signal intensities in NMR spectra by transferring the favourable electron spin polarization of paramagnetic centres to the surrounding nuclear spins through appropriate microwave irradiation. In our group at EPFL, two complementary DNP techniques are under investigation: the combination of DNP with magic angle spinning at temperatures near 100 K ('MAS-DNP'), and the combination of DNP at 1.2 K with rapid heating followed by the transfer of the sample to a high-resolution magnet ('dissolution DNP'). Recent applications of MAS-DNP to surfaces, as well as new developments of magnetization transfer of 1H to 13C at 1.2 K prior to dissolution will illustrate the work performed in our group. A second part of the paper will give an overview of some 'non-enhanced' activities of our laboratory in liquid- and solid-state NMR.

Monday, December 19, 2016

Rational design of dinitroxide biradicals for efficient cross-effect dynamic nuclear polarization #DNPNMR


Kubicki, D.J., et al., Rational design of dinitroxide biradicals for efficient cross-effect dynamic nuclear polarization. Chem. Sci., 2016. 7(1): p. 550-558.


A series of 37 dinitroxide biradicals have been prepared and their performance studied as polarizing agents in cross-effect DNP NMR experiments at 9.4 T and 100 K in 1,1,2,2-tetrachloroethane (TCE). We observe that in this regime the DNP performance is strongly correlated with the substituents on the polarizing agents, and electron and nuclear spin relaxation times, with longer relaxation times leading to better enhancements. We also observe that deuteration of the radicals generally leads to better DNP enhancement but with longer build-up time. One of the new radicals introduced here provides the best performance obtained so far under these conditions.

Friday, December 16, 2016

Correction: Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids #DNPNMR


Corzilius, B., Correction: Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids. Phys. Chem. Chem. Phys., 2016. 18(42): p. 29643-29643.


Correction for 'Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids' by Bjorn Corzilius et al., Phys. Chem. Chem. Phys., 2016, DOI: 10.1039/c6cp04621e.

Thursday, December 15, 2016

[NMR] Prestigous PhD fellowships

From the Ampere Magnetic Resonance List


URGENT !! Announcement of prestigious Fellowship for PhD candidates The Faculty of Science of Leiden University offers prestigious and competitive scholarships http://huygens.researchschool.nl/ for PhD candidates to work in interdisciplinary research projects within the Faculty of Sciences at Leiden University.

Candidates qualified to start a PhD program in 2017 and interested in a project that combines EPR with solution and solid state NMR to determine the mechanism of copper proteins should contact Huub de Groot (groot_h@lic.leidenuniv.nl).

If interested, or if you have any questions, please contact us as soon as possible, preferentially not later than Dec. 19th 2016.

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Wednesday, December 14, 2016

Microwave-gated dynamic nuclear polarization #DNPNMR


Bornet, A., et al., Microwave-gated dynamic nuclear polarization. Phys. Chem. Chem. Phys., 2016. 18(44): p. 30530-30535.


Dissolution dynamic nuclear polarization (D-DNP) has become a method of choice to enhance signals in nuclear magnetic resonance (NMR). Recently, we have proposed to combine cross-polarization (CP) with D-DNP to provide high polarization P(13C) in short build-up times. In this paper, we show that switching microwave irradiation off for a few hundreds of milliseconds prior to CP can significantly boost the efficiency. By implementing microwave gating, 13C polarizations on sodium [1-13C]acetate as high as 64% could be achieved with a polarization build-up time constant as short as 160 s. A polarization of P(13C) = 78% could even be reached for [13C]urea.

Monday, December 12, 2016

Trityl-based alkoxyamines as NMP controllers and spin-labels


Audran, G., et al., Trityl-based alkoxyamines as NMP controllers and spin-labels. Polym. Chem., 2016. 7(42): p. 6490-6499.


Recently, new applications of trityl-nitroxide biradicals were proposed. In the present study, attachment of a trityl radical to alkoxyamines was performed for the first time. The rate constants kd of C-ON bond homolysis in these alkoxyamines were measured and found to be similar to those for alkoxyamines without a trityl moiety. The electron paramagnetic resonance (EPR) spectra of the products of alkoxyamine homolysis (trityl-TEMPO and trityl-SG1 biradicals) were recorded, and the corresponding exchange interactions were estimated. The decomposition of trityl-alkoxyamines showed more than an 80% yield of biradicals, meaning that the C-ON bond homolysis is the main reaction. The suitability of these labelled initiators/controllers for polymerisation was exemplified by means of a successful nitroxide-mediated polymerisation (NMP) of styrene. Thus, this is the first report of a spin-labelled alkoxyamine suitable for NMP.

Friday, December 9, 2016

Diffusion-mediated 129Xe gas depolarization in magnetic field gradients during continuous-flow optical pumping


Burant, A. and R.T. Branca, Diffusion-mediated 129Xe gas depolarization in magnetic field gradients during continuous-flow optical pumping. J Magn Reson, 2016. 273: p. 124-129.


The production of large volumes of highly polarized noble gases like helium and xenon is vital to applications of magnetic resonance imaging and spectroscopy with hyperpolarized (HP) gas in humans. In the past ten years, 129Xe has become the gas of choice due to its lower cost, higher availability, relatively high tissue solubility, and wide range of chemical shift values. Though near unity levels of xenon polarization have been achieved in-cell using stopped-flow Spin Exchange Optical Pumping (SEOP), these levels are currently unmatched by continuous-flow SEOP methods. Among the various mechanisms that cause xenon relaxation, such as persistent and transient xenon dimers, wall collisions, and interactions with oxygen, relaxation due to diffusion in magnetic field gradients, caused by rapidly changing magnetic field strength and direction, is often ignored. However, during continuous-flow SEOP production, magnetic field gradients may not have a negligible contribution, especially considering that this methodology requires the combined use of magnets with very different characteristics (low field for spin exchange optical pumping and high field for the reduction of xenon depolarization in the solid state during the freeze out phase) that, when placed together, inevitably create magnetic field gradients along the gas-flow-path. Here, a combination of finite element analysis and Monte Carlo simulations is used to determine the effect of such magnetic field gradients on xenon gas polarization with applications to a specific, continuous-flow hyperpolarization system.

Monday, December 5, 2016

High-Resolution Two-Field Nuclear Magnetic Resonance Spectroscopy


Cousin, S.F., et al., High-Resolution Two-Field Nuclear Magnetic Resonance Spectroscopy. Phys. Chem. Chem. Phys., 2016.


Nuclear Magnetic Resonance (NMR) is a ubiquitous branch of spectroscopy that can explore matter on the scale of the atom. Significant improvements in sensitivity and resolution have been driven by a steady increase of static magnetic field strengths. However, some properties of nuclei may be more favourable at low magnetic fields. For example, line-broadening due to chemical shift anisotropy increases sharply at higher magnetic fields. Here, we present a two-field NMR spectrometer that permits the application of rf-pulses and acquisition of NMR signals in two magnetic centres. Our prototype operates at 14.1 T and 0.33 T. The main features of this system are demonstrated by novel NMR experiments that correlate zero-quantum coherences at low magnetic field with single quantum coherences at high magnetic field, so that high resolution can be achieved in both dimensions, despite a ca. 10 ppm inhomogeneity of the low field centre. Two-field NMR spectroscopy offers the possibility to circumvent the limits of high magnetic fields, while benefiting from their exceptional sensitivity and resolution. This approach opens new avenues for NMR above 1 GHz.

Friday, December 2, 2016

Nuclear spin-lattice relaxation in nitroxide spin-label EPR


Marsh, D., Nuclear spin-lattice relaxation in nitroxide spin-label EPR. J Magn Reson, 2016. 272: p. 166-171.


Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T1-exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b=Wn/(2We), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14N-relaxation: T1n=1/Wn. Results are compared and contrasted with those for the two-level 15N-nitroxide system.

Monday, November 28, 2016

Dissolution Dynamic Nuclear Polarization capability study with fluid path


Malinowski, R.M., et al., Dissolution Dynamic Nuclear Polarization capability study with fluid path. J Magn Reson, 2016. 272: p. 141-146.


Signal enhancement by hyperpolarization is a way of overcoming the low sensitivity in magnetic resonance; MRI in particular. One of the most well-known methods, dissolution Dynamic Nuclear Polarization, has been used clinically in cancer patients. One way of ensuring a low bioburden of the hyperpolarized product is by use of a closed fluid path that constitutes a barrier to contamination. The fluid path can be filled with the pharmaceuticals, i.e. imaging agent and solvents, in a clean room, and then stored or immediately used at the polarizer. In this study, we present a method of filling the fluid path that allows it to be reused. The filling method has been investigated in terms of reproducibility at two extrema, high dose for patient use and low dose for rodent studies, using [1-13C]pyruvate as example. We demonstrate that the filling method allows high reproducibility of six quality control parameters with standard deviations 3-10 times smaller than the acceptance criteria intervals in clinical studies.

Friday, November 25, 2016

Cross relaxation in nitroxide spin labels


Marsh, D., Cross relaxation in nitroxide spin labels. J Magn Reson, 2016. 272: p. 172-180.


Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent.

Wednesday, November 23, 2016

Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking


Zhang, G., et al., Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking. J Magn Reson, 2016. 272: p. 123-128.


Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13C peaks, on the chemical shift offset of coupled nuclei, such as 1H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [13C, 1H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02ppm when measured on a 400MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance.

Monday, November 21, 2016

Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids #DNPNMR


Corzilius, B., Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids. Phys. Chem. Chem. Phys., 2016. 18(39): p. 27190-27204.


Dynamic nuclear polarization (DNP) is a powerful method to enhance sensitivity especially of solid-state magic-angle spinning (MAS) NMR by up to several orders of magnitude. The increased interest both from a practical as well as theoretical viewpoint has spawned several fields of active research such as the development of new polarizing agents with improved or unique properties and description of the underlying DNP mechanisms such as solid effect (SE) and cross effect (CE). Even though a novel class of unique polarizing agents based on high-spin metal ions such as Gd(iii) and Mn(ii) has already been utilized for MAS DNP a theoretical description of the involved DNP mechanism is still incomplete. Here, we review several aspects of DNP-relevant electron-paramagnetic resonance (EPR) properties of the general class of these half-integer high-spin metal ions with isotropic Zeeman interaction but significant zero-field splitting (ZFS). While the SE can be relatively easily described similar to that of a S = 1/2 system and is assumed to be effective only for polarizing agents featuring a narrow central EPR transitions (i.e., mS = -1/2 [rightward arrow] +1/2) with respect to the nuclear Larmor frequency, the CE between two high-spin ions requires a more detailed theoretical investigation due to a multitude of possible transitions and matching conditions. This is especially interesting in light of recent understanding of CE being induced by MAS-driven level anti-crossings (LACs) between dipolar-coupled electron spins. We discuss the requirements of such CE-enabling LACs to occur due to anisotropy of ZFS, the expected adiabaticity, and the resulting possibilities of high-spin metal ion pairs to act as polarizing agents for DNP. This theoretical description serves as a framework for a detailed experimental study published directly following this work.

Friday, November 18, 2016

Following Metabolism in Living Microorganisms by Hyperpolarized (1)H NMR


Dzien, P., et al., Following Metabolism in Living Microorganisms by Hyperpolarized (1)H NMR. J Am Chem Soc, 2016. 138(37): p. 12278-86.


Dissolution dynamic nuclear polarization (dDNP) is used to enhance the sensitivity of nuclear magnetic resonance (NMR), enabling monitoring of metabolism and specific enzymatic reactions in vivo. dDNP involves rapid sample dissolution and transfer to a spectrometer/scanner for subsequent signal detection. So far, most biologically oriented dDNP studies have relied on hyperpolarizing long-lived nuclear spin species such as (13)C in small molecules. While advantages could also arise from observing hyperpolarized (1)H, short relaxation times limit the utility of prepolarizing this sensitive but fast relaxing nucleus. Recently, it has been reported that (1)H NMR peaks in solution-phase experiments could be hyperpolarized by spontaneous magnetization transfers from bound (13)C nuclei following dDNP. This work demonstrates the potential of this sensitivity-enhancing approach to probe the enzymatic process that could not be suitably resolved by (13)C dDNP MR. Here we measured, in microorganisms, the action of pyruvate decarboxylase (PDC) and pyruvate formate lyase (PFL)-enzymes that catalyze the decarboxylation of pyruvate to form acetaldehyde and formate, respectively. While (13)C NMR did not possess the resolution to distinguish the starting pyruvate precursor from the carbonyl resonances in the resulting products, these processes could be monitored by (1)H NMR at 500 MHz. These observations were possible in both yeast and bacteria in minute-long kinetic measurements where the hyperpolarized (13)C enhanced, via (13)C --> (1)H cross-relaxation, the signals of protons binding to the (13)C over the course of enzymatic reactions. In addition to these spontaneous heteronuclear enhancement experiments, single-shot acquisitions based on J-driven (13)C --> (1)H polarization transfers were also carried out. These resulted in higher signal enhancements of the (1)H resonances but were not suitable for multishot kinetic studies. The potential of these (1)H-based approaches for measurements in vivo is briefly discussed.

Wednesday, November 16, 2016

Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures #DNPNMR


Grüning, W.R., et al., Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures. Helvetica Chimica Acta, 2016: p. n/a-n/a.


Hyperpolarization of NMR-active nuclei is key to gather high quality spectra of rare species and insensitive isotopes. We have recently established that silica-based materials containing regularly distributed nitroxyl radicals connected to the silica matrix by flexible linkers can serve as promising polarization matrices in DNP. Here we investigate the influence of the linker on the efficiency of the polarization. The materials were fully characterized and exhibit high surface areas and narrow pore size distributions with a tunable amount of phenyl azide groups over a broad range of concentrations. The phenyl azide groups can be easily functionalized via a two-step procedure into 4-carboxy-2,2,6,6-tetramethyl-1-oxyl-piperidine (TEMPO) to give polarizing matrices with controllable radical content. The DNP efficiency was found to be similar as in materials with flexible linkers, both for MAS at 105 K and dissolution DNP at 4 K. This article is protected by copyright. All rights reserved.

Monday, November 14, 2016

Open Position at Bridge12: Scientist - Magnetic Resonance #DNPNMR

Bridge12 has an open position for a Scientist - Magnetic Resonance.



Open Position: Scientist - Magnetic Resonance Spectroscopy


Bridge12 is a small business focused on the development of cutting-edge microwave and terahertz (THz) instrumentation for use in scientific research such as Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR) and Dynamic Nuclear Polarization (DNP) spectroscopy. The company has a worldwide customer base and conducts groundbreaking research on applications of microwave/THz radiation in novel fields, often in collaboration with leading academic institutes.

Position Overview

As a scientist at Bridge12, you will work on multidisciplinary projects covering large aspects of magnetic resonance, instrumentation design, development of prototypes and conduct research. The position requires creativity in a wide range of areas of magnetic resonance spectroscopy including NMR and EPR spectroscopy, imaging, and instrument development. We are looking for a highly motivated, highly organized individual who enjoys an innovative, interdisciplinary environment and the challenges that come with the manufacturing of high-tech, scientific instrumentation. You will work out of the Bridge12 facilities in Framingham, MA with only occasional travel (conferences, tradeshows etc.).

Responsibilities

  • Instrument development with a strong focus on Magnetic Resonance Spectroscopy (NMR, EPR, DNP, MRI). This includes the electrical and mechanical design and fabrication of NMR, EPR and DNP probes. Design of passive microwave/THz components (e.g. transmission lines, mirrors, bends, quasi-optical components) and the design of RF circuits
  • Design and conduct research to support product development
Required Skills & Experience
  • In-depth understanding of the principles of magnetic resonance spectroscopy with a strong emphasis on NMR and EPR spectroscopy
  • Experience in performing solution-state and solid-state NMR experiments, preferably on an Agilent/Varian spectrometer running VnmrJ
  • Experience in performing electromagnetic simulations for RF and microwave/THz circuits using finite element analysis tools (e.g. Ansys HFSS and Maxwell)
  • In-depth knowledge of LabVIEW and Matlab
  • Experience with 3D CAD tools for mechanical design such as Autodesk Inventor
  • Excellent verbal and written communication skills and good teamwork ethics
  • Printed Circuit Board design and prototyping (advantage)
  • Experience in designing cryogenic instrumentation (advantage)

Qualification: ​Ph.D. degree in chemistry, chemical engineering, physical chemistry, physics or equivalent or Master degree and at least 3 years of professional experience.

This is a full-time position. Bridge12 is an equal opportunity employer, and offers a competitive compensation package with excellent benefits and healthcare. In compliance with federal law, all persons hired will be required to verify identity and eligibility to work in the United States and to complete the required employment eligibility verification document form upon hire.

Please email your Resume or CV together with a cover letter to: careers@bridge12.com.


You can also find the job posting by visiting our website.

Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification


Hansen, A.E., et al., Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification. EJNMMI Phys, 2016. 3(1): p. 7.


BACKGROUND: Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. METHODS: Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. RESULTS: PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. CONCLUSIONS: Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and hyperpolarized (13)C-MRI in vivo studies.

Friday, November 11, 2016

35Cl dynamic nuclear polarization solid-state NMR of active pharmaceutical ingredients #DNPNMR


Hirsh, D.A., et al., 35Cl dynamic nuclear polarization solid-state NMR of active pharmaceutical ingredients. Phys Chem Chem Phys, 2016. 18(37): p. 25893-25904.


In this work, we show how to obtain efficient dynamic nuclear polarization (DNP) enhanced 35Cl solid-state NMR (SSNMR) spectra at 9.4 T and demonstrate how they can be used to characterize the molecular-level structure of hydrochloride salts of active pharmaceutical ingredients (APIs) in both bulk and low wt% API dosage forms. 35Cl SSNMR central-transition powder patterns of chloride ions are typically tens to hundreds of kHz in breadth, and most cannot be excited uniformly with high-power rectangular pulses or acquired under conditions of magic-angle spinning (MAS). Herein, we demonstrate the combination of DNP and 1H-35Cl broadband adiabatic inversion cross polarization (BRAIN-CP) experiments for the acquisition of high quality wideline spectra of APIs under static sample conditions, and obtain signals up to 50 times greater than in spectra acquired without the use of DNP at 100 K. We report a new protocol, called spinning-on spinning-off (SOSO) acquisition, where MAS is applied during part of the polarization delay to increase the DNP enhancements and then the MAS rotation is stopped so that a wideline 35Cl NMR powder pattern free from the effects of spinning sidebands can be acquired under static conditions. This method provides an additional two-fold signal enhancement compared to DNP-enhanced SSNMR spectra acquired under purely static conditions. DNP-enhanced 35Cl experiments are used to characterize APIs in bulk and dosage forms with Cl contents as low as 0.45 wt%. These results are compared to DNP-enhanced 1H-13C CP/MAS spectra of APIs in dosage forms, which are often hindered by interfering signals arising from the binders, fillers and other excipient materials.

Wednesday, November 9, 2016

Selective High-Resolution Detection of Membrane Protein-Ligand Interaction in Native Membranes Using Trityl-Nitroxide PELDOR


Joseph, B., et al., Selective High-Resolution Detection of Membrane Protein-Ligand Interaction in Native Membranes Using Trityl-Nitroxide PELDOR. Angew Chem Int Ed Engl, 2016. 55(38): p. 11538-42.


The orchestrated interaction of transmembrane proteins with other molecules mediates several crucial biological processes. Detergent solubilization may significantly alter or even abolish such hetero-oligomeric interactions, which makes observing them at high resolution in their native environment technically challenging. Dipolar electron paramagnetic resonance (EPR) techniques such as pulsed electro-electron double resonance (PELDOR) can provide very precise distances within biomolecules. To concurrently determine the inter-subunit interaction and the intra-subunit conformational changes in hetero-oligomeric complexes, a combination of different spin labels is required. Orthogonal spin labeling using a triarylmethyl (TAM) label in combination with a nitroxide label is used to detect protein-ligand interactions in native lipid bilayers. This approach provides a higher sensitivity and total selectivity and will greatly facilitate the investigation of multimeric transmembrane complexes employing different spin labels in the native lipid environment.

Tuesday, November 8, 2016

[NMR] Symposium in Honor of Prof. Jacob Schaefer - Jan. 6, 2017

From the Ampere Magnetic Resonance List


Could you please announce: at Washington University we are holding a special symposium in Jake Schaefer’s honor—after the release of a special issue of the Elsevier journal, Solid State Nuclear Magnetic Resonance, in his honor, to celebrate the developments of CPMAS and REDOR. 

Symposium in Honor of Jacob Schaefer

Date: Friday Jan. 6, 2017
Location: Chemistry Department, Washington University, St. Louis
Website for more information: https://sites.google.com/site/stlnmrdg/

Confirmed Speakers

Alexander Barnes, Washington University
Technology for Electron Decoupling and Pulsed DNP in Rotating Solids

Lynette Cegelski, Stanford University
CPMAS and REDOR: Bugs, Films, and Leaves

Hellmut Eckert, WWU Muenster, Germany
Inspired by Rochester 1988: Using REDOR for Structural Studies of Inorganic Glasses

Joel Garbow, Washington University School of Medicine
Monsanto to Washington University: Tales of a Schaefer Post-doc

Terry Gullion, West Virginia University
Some Recollections of REDOR and Some Observations of Peptides on Gold Nanoparticles

Joon Kim, Baylor University
How mosquitoes and algae get fat: carbon metabolic fluxes by solid-state NMR

Matt Merritt, Univ. of Florida, Gainesville
Paths Less Traveled: Using NMR to Understand Metabolism

Gary Patti, Washington University
Metabolic Anachronisms from Jake Schaefer's 1985 Lab Notebook

Ayyalusamy Ramamoorthy, Univ. of Michigan
Dynamic Structural Interactions between Membrane-Bound Cytochrome-P450 and Redox Partners by NMR

Asher Schmidt, Technion University, Israel
Bominerals interfaces and mesoporous materials surfaces: the molecular REDOR eyes expose mechanistic pathways in functional materials.

David Weliky, Michigan State University
Solid-State NMR of Viral Fusion Proteins


Sophia E. Hayes
Professor, Department of Chemistry, Washington University, 1 Brookings Dr., St. Louis, MO 63130
Office location: 407 McMillen Lab Bldg.
(314) 935-4624

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Monday, November 7, 2016

Gyrotrons for High-Power Terahertz Science and Technology at FIR UF #DNPNMR


Idehara, T. and S.P. Sabchevski, Gyrotrons for High-Power Terahertz Science and Technology at FIR UF. J Infrared Milli Terahz Waves, 2016: p. 1-25.


In this review paper, we present the recent progress in the development of a series of gyrotrons at the Research Center for Development of Far-Infrared Region, University of Fukui, that have opened the road to many novel applications in the high-power terahertz science and technology. The current status of the research in this actively developing field is illustrated by the most representative examples in which the developed gyrotrons are used as powerful and frequency-tunable sources of coherent radiation operating in a continuous-wave regime. Among them are high-precision spectroscopic techniques (most notably dynamic nuclear polarization-nuclear magnetic resonance, electron spin resonance, X-ray detected magnetic resonance, and studies of the hyperfine splitting of the energy levels of positronium), treatment and characterization of advanced materials, and new medical technologies.

Friday, November 4, 2016

Difference between Extra- and IntracellularT1Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR


Karlsson, M., et al., Difference between Extra- and IntracellularT1Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR. Angewandte Chemie, 2016. 128(43): p. 13765-13768.


Incomplete knowledge of the longitudinal relaxation time constant (T1) leads to incorrect assumptions in quantitative kinetic models of cellular systems, studied by hyperpolarized real-time NMR. Using an assay that measures the intracellular signal of small carboxylic acids in living cells, the intracellular T1 of the carboxylic acid moiety of acetate, keto-isocaproate, pyruvate, and butyrate was determined. The intracellular T1 is shown to be up to four-fold shorter than the extracellular T1. Such a large difference in T1 values between the inside and the outside of the cell has significant influence on the quantification of intracellular metabolic activity. It is expected that the significantly shorter T1 value of the carboxylic moieties inside cells is a result of macromolecular crowding. An artificial cytosol has been prepared and applied to predict the T1 of other carboxylic acids. We demonstrate the value of this prediction tool.

Wednesday, November 2, 2016

Gd(iii) and Mn(ii) complexes for dynamic nuclear polarization: small molecular chelate polarizing agents and applications with site-directed spin labeling of proteins #DNPNMR


Kaushik, M., et al., Gd(iii) and Mn(ii) complexes for dynamic nuclear polarization: small molecular chelate polarizing agents and applications with site-directed spin labeling of proteins. Phys Chem Chem Phys, 2016. 18(39): p. 27205-27218.


We investigate complexes of two paramagnetic metal ions Gd3+ and Mn2+ to serve as polarizing agents for solid-state dynamic nuclear polarization (DNP) of 1H, 13C, and 15N at magnetic fields of 5, 9.4, and 14.1 T. Both ions are half-integer high-spin systems with a zero-field splitting and therefore exhibit a broadening of the mS = -1/2 <--> +1/2 central transition which scales inversely with the external field strength. We investigate experimentally the influence of the chelator molecule, strong hyperfine coupling to the metal nucleus, and deuteration of the bulk matrix on DNP properties. At small Gd-DOTA concentrations the narrow central transition allows us to polarize nuclei with small gyromagnetic ratio such as 13C and even 15N via the solid effect. We demonstrate that enhancements observed are limited by the available microwave power and that large enhancement factors of >100 (for 1H) and on the order of 1000 (for 13C) can be achieved in the saturation limit even at 80 K. At larger Gd(iii) concentrations (>/=10 mM) where dipolar couplings between two neighboring Gd3+ complexes become substantial a transition towards cross effect as dominating DNP mechanism is observed. Furthermore, the slow spin-diffusion between 13C and 15N, respectively, allows for temporally resolved observation of enhanced polarization spreading from nuclei close to the paramagnetic ion towards nuclei further removed. Subsequently, we present preliminary DNP experiments on ubiquitin by site-directed spin-labeling with Gd3+ chelator tags. The results hold promise towards applications of such paramagnetically labeled proteins for DNP applications in biophysical chemistry and/or structural biology.

Monday, October 31, 2016

A compact X-Band resonator for DNP-enhanced Fast-Field-Cycling NMR #DNPNMR


Neudert, O., C. Mattea, and S. Stapf, A compact X-Band resonator for DNP-enhanced Fast-Field-Cycling NMR. J Magn Reson, 2016. 271: p. 7-14.


A new probehead was developed enabling Dynamic Nuclear Polarization (DNP)-enhanced Fast-Field-Cycling relaxometry at 340mT polarization field strength. It is based on a dielectric cavity resonator operating in the TM110 mode at 9.5GHz, which is suitable for both transverse and axial magnet geometries with a bore access of at least 20mm. The probehead includes a planar radio frequency coil for NMR detection and is compatible with standard 3mm NMR tubes. The resonator was assessed in terms of the microwave conversion factor and microwave-induced sample heating effects. Due to the compact size of the cavity, appreciable microwave magnetic field strengths were observed even with only moderate quality factors. Exemplary DNP experiments at 9.5GHz and 2.0GHz microwave frequency are compared for three different viscous samples, demonstrating the advantage of DNP at 9.5GHz for such systems. This new probehead enables new applications of DNP-enhanced Fast-Field-Cycling relaxometry of viscous and solid systems.

Sunday, October 30, 2016

Difference between Extra- and IntracellularT1Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR

[NMR] Summer school Theory of NMR at Schloss Windischleuba 19-25 Feb. 2017

From the Ampere Magnetic Resonance List



Summer school Theory of NMR at Schloss Windischleuba 19-25 Feb. 2017

Financed by the Volkswagen-Stiftung will be a summer school on the Theory of NMR at Youth hostel Schloss Windischleuba (40 km South of Leipzig) from Sun/19 (evening) to Sat/25 (morning) Feb. 2017. The school will focus on solid-state NMR. The subjects of the school will cover: basics of quantum mechanics, quantum mechanics for NMR, static solids, MAS, CPMAS, decoupling, recoupling, pulse techniques, AHT, Floquet, Quadrupolar nuclei, polymers, solid bio samples.

Teachers: Prof. Shimon Vega (Weizmann Institute of Science, Rechovot), Prof. Konstantin Ivanov (International Tomography Center, Novosibirsk), Prof. Madhu (TIFR Hyderabad), Prof. Kay Saalwächter (Univ. Halle-Wittenberg), Dr. Chen Song (Univ. Leipzig), Dr. Zdenek Tosner (TUM München).

Organizer: Prof. Jörg Matysik (Univ. Leipzig).


Participation and full accommodation will be free.
Transport will be partially supported.
Max number of students = 45.
Deadline for application = 9 Nov 2016.
Decision on participation within a month.
Participants are expected to stay the full period.

For application, please provide: (1) last name, (2) first name, (3) gender f/m, (4) e-mail, (5) country of laboratory, (6) head of laboratory, (7) food veg/nonveg/other, (8) arrival date, (9) departure date, (10) about three sentences describing your research project, (11) about three sentences on your motivation to participate, (12) any further information.

Please send your e-mail to: zeller@chemie.uni-leipzig.de.

****************************************************
Prof. Dr. Jörg Matysik
skype: joerg.matysik
****************************************************

Institut für Analytische Chemie
Universität Leipzig
Linnéstr. 3 (visit)
Johannisallee 29 (mail)
D-04103 Leipzig
Tel: +49-341-9736112 (direct)
Tel: +49-341-9736100 (Secr.)
Fax: +49-341-9736115

****************************************************

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Friday, October 28, 2016

[NMR] Postdoc in Levitt group on hyperpolarization

From the Ampere Magnetic Resonance List


A postdoc position (1 year, with possibility of extension) with the group of Malcolm Levitt in Southampton is open for applicants. The topic is dissolution DNP, quantum rotor induced polarization, and long-lived states. Details and the application link are here:


yours
Malcolm

------------------------------------
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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Long-lived states to sustain SABRE hyperpolarised magnetisation


Roy, S.S., et al., Long-lived states to sustain SABRE hyperpolarised magnetisation. Phys Chem Chem Phys, 2016. 18(36): p. 24905-24911.


The applicability of the magnetic resonance (MR) technique in the liquid phase is limited by poor sensitivity and short nuclear spin coherence times which are insufficient for many potential applications. Here we illustrate how it is possible to address both of these issues simultaneously by harnessing long-lived hyperpolarised spin states that are formed by adapting the Signal Amplification by Reversible Exchange (SABRE) technique. We achieve more than 4% net 1H-polarisation in a long-lived form that remains detectable for over ninety seconds by reference to proton pairs in the biologically important molecule nicotinamide and a pyrazine derivative whose in vivo imaging will offer a new route to probe disease in the future.

Wednesday, October 26, 2016

Dissolution Dynamic Nuclear Polarization capability study with fluid path


Malinowski, R.M., et al., Dissolution Dynamic Nuclear Polarization capability study with fluid path. J Magn Reson, 2016. 272: p. 141-146.


Signal enhancement by hyperpolarization is a way of overcoming the low sensitivity in magnetic resonance; MRI in particular. One of the most well-known methods, dissolution Dynamic Nuclear Polarization, has been used clinically in cancer patients. One way of ensuring a low bioburden of the hyperpolarized product is by use of a closed fluid path that constitutes a barrier to contamination. The fluid path can be filled with the pharmaceuticals, i.e. imaging agent and solvents, in a clean room, and then stored or immediately used at the polarizer. In this study, we present a method of filling the fluid path that allows it to be reused. The filling method has been investigated in terms of reproducibility at two extrema, high dose for patient use and low dose for rodent studies, using [1-13C]pyruvate as example. We demonstrate that the filling method allows high reproducibility of six quality control parameters with standard deviations 3-10 times smaller than the acceptance criteria intervals in clinical studies.

Tuesday, October 25, 2016

[NMR] Postdoctoral Fellow Position at Merck

From the Ampere Magnetic Resonance List


Dear colleagues,

We are looking for motivated candidates for an opening for NMR research of pharmaceuticals. It’s a great opportunity for anyone who would like to pursue a career in pharmaceutical industry. The position is available immediately, and interested candidates should send their CV’s to yongchao.su@merck.com AND finish the online application. The position is funded up to 3 years. Merck provides competitive annual salary and benefit for this full-time position. 


The lab has AVIII 400 MHz and 500 MHz solid-state NMR spectrometers fully equipped with probes including a 1.3 mm ultrafast spinning probe. We have frequent and convenient access to 600MHz and 700MHz solution NMR instruments. The proposed research will focus on development and application of advanced solid-state and solution NMR techniques in pharmaceutical systems including small molecule and peptide drugs and formulations. 

Can you please kindly forward to anyone who may be interested?

Thanks a lot!
Yongchao
-
Yongchao Su, Ph.D. Senior Scientist 
Merck Research Laboratories, MRLs | Merck & Co.
Phone: 215-652-0121 (office) | 3-3045 (NMR lab)
E-mail: yongchao.su@merck.com | West Point, PA

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[NMR] MR Imaging and Spectroscopy Research Staff Scientist position at the U.S. National High Magnetic Field Laboratory / University of Florida

From the Ampere Magnetic Resonance List


MR Imaging and Spectroscopy Research Staff Scientist
Advanced Magnetic Resonance Imaging and Spectroscopy Facility and National High Magnetic Field Laboratory

University of Florida

The Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility at UF seeks an MR imaging and spectroscopy scientist for the permanent research staff position of Core Research Facility Manager/Director for ≥ 11.74 Tesla vertical bore NMR/MRI instrumentation. Minimum qualifications include a Ph.D., or equivalent, in Physical Sciences or Engineering, with a demonstrated experience and expertise in techniques and applications of high field MR imaging and spectroscopy. Previous experience in pulse sequence design and implementation as well as data processing is needed. Experience working with live animals is desirable.

The successful candidate will be expected to work with the staff of the AMRIS Facility to maintain optimal instrument performance and standard protocols for imaging and spectroscopy to provide support for researchers at the University of Florida as well as external users through the NSF-funded National High Magnetic Field Laboratory (NHMFL) users program. This position offers unique opportunities to contribute to the development of the MR imaging and spectroscopy program in the AMRIS Facility and the NHMFL and to conduct independent and collaborative research projects. The position will be based in Gainesville, but will involve a close relationship with the NMR Spectroscopy and Imaging Program at the NHMFL in Tallahassee, so occasional travel to that site will be expected. Ongoing research in the Facility includes the application of MR imaging and spectroscopy to biological, biomedical, chemical, and material science research projects and the development of novel imaging and spectroscopy methods. Candidates with an interest in the development of novel methods and/or instrumentation are especially encouraged to apply.

As part of the MR imaging and spectroscopy capabilities, the AMRIS Facility houses the following state-of-the-art MRI/S and NMR systems: a 3 T Phillips Achieva, a 3 T Siemens Prisma, a 4.7 T bore Agilent VNMRS, a 5 T custom DNP polarizer, an 11 T 40 cm Bruker Biospec, an 11.7 5.4 cm Bruker Avance III, a 14.1 T 5.2 cm Bruker Avance III, a 14.1 T 5.4 cm Bruker Avance II, a 14.1 T 5.4 cm Agilent VNMRS and a 17.6 T 8.9 cm Bruker Avance III. A 21 T, 10.4 cm magnet with Bruker Avance system is housed at the NHMFL facility in Tallahassee. The successful candidate will be primarily responsible for MRI/S applications on the vertical bore magnet systems in the AMRIS Facility.

Specific job requirements:

  • Responsible for coordinating, scheduling and ensuring proper utilization of research facilities.
  • Recommend and implement operating policies and procedures in the AMRIS Facility.
  • Keep abreast of current developments and ensure compliance with relevant laws and regulations.
  • Plan and participate in research projects.
  • Help direct and modify research plans.
  • Develop methods and techniques for, and evaluates results of, experiments or studies.
  • Prepare and review manuscripts for publication and presentation at scientific meetings.
  • May serve as liaison between the AMRIS Facility and outside agencies and the general public.

For additional information on the position, please contact Dr. Joanna R. Long, jrlong@ufl.edu, or Dr. Thomas Mareci, thmareci@ufl.edu. The University of Florida is an Equal Opportunity/Access/Affirmative Action Employer. Applications will be accepted October 20-November 19 at http://explore.jobs.ufl.edu/cw/en-us/job/499229/core-research-facility-manager.

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Monday, October 24, 2016

Evidence of spin-temperature in dynamic nuclear polarization: an exact computation of the EPR spectrum #DNPNMR


Caracciolo, F., et al., Evidence of spin-temperature in dynamic nuclear polarization: an exact computation of the EPR spectrum. Phys Chem Chem Phys, 2016. 18(36): p. 25655-25662.


In dynamic nuclear polarization (DNP) experiments, the compound is driven out-of-equilibrium by the microwave (MW) irradiation of the radical electron spins. Their stationary state has been recently probed via electron double resonance (ELDOR) techniques showing, at low temperature, a broad depolarization of the electron paramagnetic resonance (EPR) spectrum under microwave irradiation. In this theoretical manuscript, we develop a numerical method to compute exactly the EPR spectrum in the presence of dipolar interactions. Our results reproduce the observed broad depolarisation and provide a microscopic justification for the spectral diffusion mechanism. We show the validity of the spin-temperature approach for typical radical concentration used in dissolution DNP protocols. In particular once the interactions are properly taken into account, the spin-temperature is consistent with the non-monotonic behavior of the EPR spectrum with a wide minimum around the irradiated frequency.

Friday, October 21, 2016

Finite element modeling of (129)Xe diffusive gas exchange NMR in the human alveoli


Stewart, N.J., J. Parra-Robles, and J.M. Wild, Finite element modeling of (129)Xe diffusive gas exchange NMR in the human alveoli. J Magn Reson, 2016. 271: p. 21-33.


Existing models of (129)Xe diffusive exchange for lung microstructural modeling with time-resolved MR spectroscopy data have considered analytical solutions to one-dimensional, homogeneous models of the lungs with specific assumptions about the alveolar geometry. In order to establish a model system for simulating the effects of physiologically-realistic changes in physical and microstructural parameters on (129)Xe exchange NMR, we have developed a 3D alveolar capillary model for finite element analysis. To account for the heterogeneity of the alveolar geometry across the lungs, we have derived realistic geometries for finite element analysis based on 2D histological samples and 3D micro-CT image volumes obtained from ex vivo biopsies of lung tissue from normal subjects and patients with interstitial lung disease. The 3D alveolar capillary model permits investigation of the impact of alveolar geometrical parameters and diffusion and perfusion coefficients on the in vivo measured (129)Xe CSSR signal response. The heterogeneity of alveolar microstructure that is accounted for in image-based models resulted in considerable alterations to the shape of the (129)Xe diffusive uptake curve when compared to 1D models. Our findings have important implications for the future design and optimization of (129)Xe MR experiments and in the interpretation of lung microstructural changes from this data.

Wednesday, October 19, 2016

Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization #DNPNMR


Viennet, T., et al., Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization. Angew Chem Int Ed Engl, 2016. 55(36): p. 10746-50.Viennet, T., et al., Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization. Angew Chem Int Ed Engl, 2016. 55(36): p. 10746-50.


Nuclear magnetic resonance (NMR) spectroscopy has the intrinsic capabilities to investigate proteins in native environments. In general, however, NMR relies on non-natural protein purity and concentration to increase the desired signal over the background. We here report on the efficient and specific hyperpolarization of low amounts of a target protein in a large isotope-labeled background by combining dynamic nuclear polarization (DNP) and the selectivity of protein interactions. Using a biradical-labeled ligand, we were able to direct the hyperpolarization to the protein of interest, maintaining comparable signal enhancement with about 400-fold less radicals than conventionally used. We could selectively filter out our target protein directly from crude cell lysate obtained from only 8 mL of fully isotope-enriched cell culture. Our approach offers effective means to study proteins with atomic resolution in increasingly native concentrations and environments.

Monday, October 17, 2016

[NMR] Deadline 25 October: Two Research Fellow positions and one PhD studentship at University of Southampton #DNPNMR

From the Ampere Magnetic Resonance List





Dear Colleagues,

I have two open Reserach Fellow Positions and a fully funded PhD studentship in my group (http://www.southampton.ac.uk/chemistry/about/staff/pileio.page) at the University of Southampton.

* Post-Doctoral Research Fellowship in nuclear magnetic resonance in the research group of Dr Giuseppe Pileio, in collaboration with Prof Malcolm H Levitt. The project, funded by EPSRC(UK), concerns the development of NMR hardware and methodology that combines supercritical fluids with long-lived states NMR and dissolution-DNP to prolong the storage of hyperpolarised spin order and allow it to be transported remotely from the production site. The position is tenable from 1 December 2016 or as soon as possible thereafter with initial appointment for 2 years but with the possibility of a further extension of 1 more years, subject to project requirements. For further details and how to apply please follow this link: https://jobs.soton.ac.uk/Vacancy.aspx?ref=785816EB<https://jobs.soton.ac.uk/Vacancy.aspx?ref=785816EB>

* A 3 years PhD studentship is also available on the same project with application deadline 31 October 2016 and a salary of £14,296 per annum. For further details and how to apply please follow this link: https://jobs.soton.ac.uk/Vacancy.aspx?ref=782416EB . Please note that: due to funding restrictions this position is only open to UK/EU applicants

* Post-Doctoral Research Fellowship in nuclear magnetic resonance in the research group of Dr Giuseppe Pileio. The project, funded by EPSRC under the First Grant scheme, concerns the development of NMR methodology to probe translational dynamics in porous media by singlet-state NMR spectroscopy. The position is tenable from 1 November 2016 or as soon as possible thereafter with appointment for 1 year but with the possibility of a further extension of 1 more year, subject to funding and project requirements. For further details and how to apply please follow this link: https://jobs.soton.ac.uk/Vacancy.aspx?ref=785516EB

University of Southampton is a UK Russell Group university positioned in the top 1% of world universities according to QS World University Rankings. We have an international reputation for research, teaching and enterprise activities. Southampton is particularly well known for its magnetic resonance and computational chemistry research.

Many Thanks,
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

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