Friday, February 27, 2015

Dynamic nuclear polarization enhancement of protons and vanadium-51 in the presence of pH-dependent vanadyl radicals


Perez Linde, A.J., et al., Dynamic nuclear polarization enhancement of protons and vanadium-51 in the presence of pH-dependent vanadyl radicals. Magn Reson Chem, 2015. 53(2): p. 88-92.


We report applications of dynamic nuclear polarization to enhance proton and vanadium-51 polarization of vanadyl sulfate samples doped with TOTAPOL under magic angle spinning conditions. The electron paramagnetic resonance response stemming from the paramagnetic (51) V species was monitored as a function of pH, which can be adjusted to improve the enhancement of the proton polarization. By means of cross-polarization from the proton bath, (51) V spins could be hyperpolarized. Enhancement factors, build-up times, and longitudinal relaxation times T1 ((1) H) and T1 ((51) V) were investigated as a function of pH. Copyright (c) 2014 John Wiley & Sons, Ltd.

Wednesday, February 25, 2015

Hyperpolarized [1,(13)C]pyruvate in lysed human erythrocytes: effects of co-substrate supply on reaction time courses


Pages, G., Y.L. Tan, and P.W. Kuchel, Hyperpolarized [1,(13)C]pyruvate in lysed human erythrocytes: effects of co-substrate supply on reaction time courses. NMR Biomed, 2014. 27(10): p. 1203-10.


Hyperpolarized [1,(13)C]pyruvate was injected rapidly into haemolysates in which hydrolysis of nicotinamide adenine dinucleotide (phosphate) (NAD(P))/NAD(P)H had been inhibited with nicotinamide. Haemolysates provide a stable glycolytic system in which membrane permeability is not a flux-controlling step, and they enable the concentration of NADH to be adjusted experimentally while keeping the rest of the sample with the same composition as that of the cytoplasm of the cell (albeit diluted twofold at the time of injection of the [1,(13)C]pyruvate). We showed that the maximum amplitude of the (13)C NMR signal from the [1,(13)C]L-lactate, produced from [1,(13)C]pyruvate, and the time at which it occurred was dependent on NADH concentration, as predicted by enzyme-kinetic analysis. The main feature of such curves was dictated by the immediacy of the supply of the co-substrate of lactate dehydrogenase (LDH, EC 1.1.1.27), and we posit that this also pertains in vivo in various tissues including neoplasms. By constructing an appropriate mathematical model and by using a Markov-chain Monte Carlo approach, we fitted experimental data to estimate LDH and NADH concentrations. Experiments carried out with only endogenous NADH present enabled the estimation of its effective concentration in human RBCs; the ability to make this estimate is a special feature of the rapid-dissolution dynamic nuclear polarization method. We found an endogenous NADH concentration in human RBCs two to four times higher than previously reported.

Monday, February 23, 2015

NMR hyperpolarization techniques for biomedicine


Nikolaou, P., B.M. Goodson, and E.Y. Chekmenev, NMR hyperpolarization techniques for biomedicine. Chemistry, 2015. 21(8): p. 3156-66.


Recent developments in NMR hyperpolarization have enabled a wide array of new in vivo molecular imaging modalities, ranging from functional imaging of the lungs to metabolic imaging of cancer. This Concept article explores selected advances in methods for the preparation and use of hyperpolarized contrast agents, many of which are already at or near the phase of their clinical validation in patients.

Friday, February 20, 2015

Insights into the Catalytic Activity of Nitridated Fibrous Silica (KCC-1) Nanocatalysts from15N and29Si NMR Spectroscopy Enhanced by Dynamic Nuclear Polarization


Lilly Thankamony, A.S., et al., Insights into the Catalytic Activity of Nitridated Fibrous Silica (KCC-1) Nanocatalysts from15N and29Si NMR Spectroscopy Enhanced by Dynamic Nuclear Polarization. Angewandte Chemie, 2015. 127(7): p. 2218-2221.


Fibrous nanosilica (KCC-1) oxynitrides are promising solid-base catalysts. Paradoxically, when their nitrogen content increases, their catalytic activity decreases. This counterintuitive observation is explained here for the first time using 15N-solid-state NMR spectroscopy enhanced by dynamic nuclear polarization.

Wednesday, February 18, 2015

[NMR] Summer School on Nuclear Spin Hyperpolarisation Techniques

From the Ampere Magnetic Resonance List


Dear Colleagues,

we are happy to announce that the next Summer School on Nuclear Spin Hyperpolarisation Techniques, organised within the EU-COST Framework (Action TD-1103), is now open for registration.

If interested, please register through the website: https://www.ocs.soton.ac.uk/index.php/cost/cost2015UK/index

The school will be held in an hotel within the beautiful Marwell Zoo and Wildlife Park nearby Southampton, UK. Social events include a Zoo Safari and a BBQ at the Zoo.

The main purpose of the school is to train the young generation of scientists (PhD's and PostDocs) working in the field of magnetic resonance in novel methodologies for nuclear spin hyperpolarisation. For this purpose the school will discuss several hyperpolarisation techniques:

* Solid-State DNP
* dissolution-DNP
* Overhauser-DNP
* PHIP/SABRE (ParaHydrogen Induced Polarisation)
* CIDNP (Chemically induced DNP)
* QRIP (Quantum Rotor Induced Polarisation)

at 4 different levels: Theory, Simulations, Instrumentation and Applications.

The school is coordinated by Giuseppe Pileio (University of Southampton, UK) and Björn Corzilius (Goethe University Frankfurt, DE);

It boasts a rich list of top class teachers and scientists whose researches have contributed to estabilish the field of nuclear spin hyperpolarisation:

* Shimon Vega (Weizmann Institite, IL)
* Bob Griffin (MIT, Cambridge, US)
* Kevin Brindle (University of Cambridge, UK)
* Walter Kockenberger (University of Nottingham, UK)
* Ilya Kuprov (University of Southampton, UK)
* Jan-Henrik Arderkjaeren-Larsen (DTU Copenhagen, DK)
* Sami Jannin (EPFL, CH)
* Marina Bennati (MPI, Göttingen, DE)
* Marco Tessari (IMM, Nijmegen, NL)

N.B.: The school is open to PhD's, PostDocs and early career scientists but we can allow only a total number of 30 participants. Places will be assigned on a first come first served base so please do not wait the last minute to register! People from countries enrolled in the COST Action are entitled to a fixed reimbursement of 500€.

Students grants are provided by EU-COST Action TD-1103. The Zoo Safari and the BBQ have been generously offered by Bruker. Oxford Instruments and Cortecnet have generously offered drinks for all dinners.

Looking forward to seeing you at the School,
Giuseppe Pileio and Björn Corzilius

Dr. Giuseppe Pileio, PhD
Senior Research Fellow,
School of Chemistry,
Building 30 - Room 3047,
University of Southampton,
University Road, SO17 1BJ,
Internal Post Code: M16,
Southampton, Hampshire, UK.

Tel.: +44 (023) 80 59 4146


ORCID: 0000-0001-9223-3896

[NMR] Registration Hyperpolarized Magnetic Resonance meeting open!

From the Ampere Magnetic Resonance List


Dear Colleagues,

With this email we would like to remind you that the registration for the Hyperpolarized Magnetic Resonance meeting is now open!
This symposium combines the COST action EUROHyperPOL final meeting with the 5th international DNP symposium.

Where: Egmond aan Zee (the Netherlands)
When: Augustus 31st till September 4th, 2015

Deadlines Early bird registration 30/04/2015
Abstract submission
(to be considered for short talk) 30/04/2015
Abstract submission
(poster presentations only) 30/06/2015

More information: http://www.nmr-nl.org/hyperpolarizedMR
Registration: http://www.nmr-nl.org/hyperpolarizedMR/Registration

With kind regards,
The organizing committee

--

Marian de With
Radboud University | Institute for Molecules and Materials
Secretary for depts. of Biophysical Chemistry, Solid State NMR and Theoretical Chemistry
Tel. +31 24 3652678
Web: www.ru.nl/science/solidstatenmr, www.ru.nl/biophyschem, www.theochem.ru.nl

Visiting address:
Heyendaalseweg 135 | 6525 AJ Nijmegen | HG03.344
Postal address:
Postbox 9010 | Internal postbus 84 | 6500 GL Nijmegen

Out of office on Mondays!

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

Monday, February 16, 2015

Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures


Lego, D., et al., Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures. NMR Biomed, 2014. 27(7): p. 810-6.


Parahydrogen-induced polarization (PHIP) is a promising new tool for medical applications of MR, including MRI. The PHIP technique can be used to transfer high non-Boltzmann polarization, derived from parahydrogen, to isotopes with a low natural abundance or low gyromagnetic ratio (e.g. (13)C), thus improving the signal-to-noise ratio by several orders of magnitude. A few molecules acting as metabolic sensors have already been hyperpolarized with PHIP, but the direct hyperpolarization of drugs used to treat neurological disorders has not been accomplished until now. Here, we report on the first successful hyperpolarization of valproate (valproic acid, VPA), an important and commonly used antiepileptic drug. Hyperpolarization was confirmed by detecting the corresponding signal patterns in the (1)H NMR spectrum. To identify the optimal experimental conditions for the conversion of an appropriate VPA precursor, structurally related molecules with different side chains were analyzed in different solvents using various catalytic systems. The presented results include hyperpolarized (13)C NMR spectra and proton images of related systems, confirming their applicability for MR studies. PHIP-based polarization enhancement may provide a new MR technique to monitor the spatial distribution of valproate in brain tissue and to analyze metabolic pathways after valproate administration.

Friday, February 13, 2015

Long-lived spin States for low-field hyperpolarized gas MRI


Kovtunov, K.V., et al., Long-lived spin States for low-field hyperpolarized gas MRI. Chemistry, 2014. 20(45): p. 14629-32.


Parahydrogen induced polarization was employed to prepare a relatively long-lived correlated nuclear spin state between methylene and methyl protons in propane gas. Conventionally, such states are converted into a strong NMR signal enhancement by transferring the reaction product to a high magnetic field in an adiabatic longitudinal transport after dissociation engenders net alignment (ALTADENA) experiment. However, the relaxation time T1 of approximately 0.6 s of the resulting hyperpolarized propane is too short for potential biomedical applications. The presented alternative approach employs low-field MRI to preserve the initial correlated state with a much longer decay time TLLSS =(4.7+/-0.5) s. While the direct detection at low-magnetic fields (e.g. 0.0475 T) is challenging, we demonstrate here that spin-lock induced crossing (SLIC) at this low magnetic field transforms the long-lived correlated state into an observable nuclear magnetization suitable for MRI with sub-millimeter and sub-second spatial and temporal resolution, respectively. Propane is a non-toxic gas, and therefore, these results potentially enable low-cost high-resolution high-speed MRI of gases for functional imaging of lungs and other applications.

Wednesday, February 11, 2015

Natural Abundance N NMR by Dynamic Nuclear Polarization: Fast Analysis of Binding Sites of a Novel Amine-Carboxyl-Linked Immobilized Dirhodium Catalyst


Gutmann, T., et al., Natural Abundance N NMR by Dynamic Nuclear Polarization: Fast Analysis of Binding Sites of a Novel Amine-Carboxyl-Linked Immobilized Dirhodium Catalyst. Chemistry, 2015: p. n/a-n/a.


A novel heterogeneous dirhodium catalyst has been synthesized. This stable catalyst is constructed from dirhodium acetate dimer (Rh2 (OAc)4 ) units, which are covalently linked to amine- and carboxyl-bifunctionalized mesoporous silica (SBA-15NH2 COOH). It shows good efficiency in catalyzing the cyclopropanation reaction of styrene and ethyl diazoacetate (EDA) forming cis- and trans-1-ethoxycarbonyl-2-phenylcyclopropane. To characterize the structure of this catalyst and to confirm the successful immobilization, heteronuclear solid-state NMR experiments have been performed. The high application potential of dynamic nuclear polarization (DNP) NMR for the analysis of binding sites in this novel catalyst is demonstrated. Signal-enhanced 13 C CP MAS and 15 N CP MAS techniques have been employed to detect different carboxyl and amine binding sites in natural abundance on a fast time scale. The interpretation of the experimental chemical shift values for different binding sites has been corroborated by quantum chemical calculations on dirhodium model complexes.

Tuesday, February 10, 2015

PDRA opportunities to work in hyperpolarisation.

From the Ampere Magnetic Resonance List


We have 5 positions available to work on developing parahydrogen derived hyperpolarisation methods in the York Centre for Hyperpolarisation in Magnetic Resonance (http://www.york.ac.uk/chym/).

The posts focus on developing the theoretical description of SABRE, developing MRI applications for SABRE, improving the catalytic transfer process and supporting the hardware needs associated with sample preparation and delivery.

The adverts for these positions can be found at:


The closing date is the 23 of February.

Regards
Simon Duckett

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Monday, February 9, 2015

Dynamic nuclear polarization of a glassy matrix prepared by solid state mechanochemical amorphization of crystalline substances

This is a very interesting article describing the preparation of a sample for DNP by co-milling the analyte with the polarizing substrate. For a long time it was thought that just mechanically mixing the polarizing agent with the analyte will not result in a sample that is useful for DNP because the radical has to be mixed at an atomic level. Clearly this article demonstrate that this is not necessary. This will open up DNP to be used with a complete class of new materials.



Elisei, E., et al., Dynamic nuclear polarization of a glassy matrix prepared by solid state mechanochemical amorphization of crystalline substances. Chemical Communications, 2015. 51(11): p. 2080-2083.


A mechanochemical "solvent-free" route is presented for the preparation of solid samples ready to be employed in the Dynamic Nuclear Polarization (DNP). 1H-DNP build-up curves at 3.46 T as a function of temperature and radical concentration show steady state nuclear polarization of 10% (0.5% TEMPO concentration at 1.75 K).

Friday, February 6, 2015

Insights into the Catalytic Activity of Nitridated Fibrous Silica (KCC-1) Nanocatalysts from15N and29Si NMR Spectroscopy Enhanced by Dynamic Nuclear Polarization


Lilly Thankamony, A.S., et al., Insights into the Catalytic Activity of Nitridated Fibrous Silica (KCC-1) Nanocatalysts from15N and29Si NMR Spectroscopy Enhanced by Dynamic Nuclear Polarization. Angewandte Chemie, 2014: p. n/a-n/a.


Fibrous nanosilica (KCC-1) oxynitrides are promising solid-base catalysts. Paradoxically, when their nitrogen content increases, their catalytic activity decreases. This counterintuitive observation is explained here for the first time using 15N-solid-state NMR spectroscopy enhanced by dynamic nuclear polarization.

Wednesday, February 4, 2015

Long-lived spin States for low-field hyperpolarized gas MRI


Kovtunov, K.V., et al., Long-lived spin States for low-field hyperpolarized gas MRI. Chemistry, 2014. 20(45): p. 14629-32.


Parahydrogen induced polarization was employed to prepare a relatively long-lived correlated nuclear spin state between methylene and methyl protons in propane gas. Conventionally, such states are converted into a strong NMR signal enhancement by transferring the reaction product to a high magnetic field in an adiabatic longitudinal transport after dissociation engenders net alignment (ALTADENA) experiment. However, the relaxation time T1 of approximately 0.6 s of the resulting hyperpolarized propane is too short for potential biomedical applications. The presented alternative approach employs low-field MRI to preserve the initial correlated state with a much longer decay time TLLSS =(4.7+/-0.5) s. While the direct detection at low-magnetic fields (e.g. 0.0475 T) is challenging, we demonstrate here that spin-lock induced crossing (SLIC) at this low magnetic field transforms the long-lived correlated state into an observable nuclear magnetization suitable for MRI with sub-millimeter and sub-second spatial and temporal resolution, respectively. Propane is a non-toxic gas, and therefore, these results potentially enable low-cost high-resolution high-speed MRI of gases for functional imaging of lungs and other applications.

Monday, February 2, 2015

Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures


Lego, D., et al., Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures. NMR Biomed, 2014. 27(7): p. 810-6.


Parahydrogen-induced polarization (PHIP) is a promising new tool for medical applications of MR, including MRI. The PHIP technique can be used to transfer high non-Boltzmann polarization, derived from parahydrogen, to isotopes with a low natural abundance or low gyromagnetic ratio (e.g. (13)C), thus improving the signal-to-noise ratio by several orders of magnitude. A few molecules acting as metabolic sensors have already been hyperpolarized with PHIP, but the direct hyperpolarization of drugs used to treat neurological disorders has not been accomplished until now. Here, we report on the first successful hyperpolarization of valproate (valproic acid, VPA), an important and commonly used antiepileptic drug. Hyperpolarization was confirmed by detecting the corresponding signal patterns in the (1)H NMR spectrum. To identify the optimal experimental conditions for the conversion of an appropriate VPA precursor, structurally related molecules with different side chains were analyzed in different solvents using various catalytic systems. The presented results include hyperpolarized (13)C NMR spectra and proton images of related systems, confirming their applicability for MR studies. PHIP-based polarization enhancement may provide a new MR technique to monitor the spatial distribution of valproate in brain tissue and to analyze metabolic pathways after valproate administration.