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Yamabayashi T, Horii Y, Li ZY, Yamashita M. Magnetic Relaxations of Chromium Nitride Porphyrinato Complexes Driven by the Anisotropic g-Factor. Chemistry 2024; 30:e202303082. [PMID: 37880199 DOI: 10.1002/chem.202303082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
Molecule-based magnetic materials are useful candidates as the spin qubit due to their long coherence time and high designability. The anisotropy of the g-values of the metal complexes can be utilized to access the individual spin of the metal complexes, making it possible to achieve the scalable molecular spin qubit. For this goal, it is important to evaluate the effect of g-value anisotropy on the magnetic relaxation behaviour. This study reports the slow magnetic relaxation behaviour of chromium nitride (CrN2+ ) porphyrinato complex (1), which is structurally and magnetically similar with the vanadyl (VO2+ ) porphyrinato complex (2) which is known as the excellent spin qubit. Detailed analyses for vibrational and dynamical magnetism of 1 and 2 revealed that g-value anisotropy accelerates magnetic relaxations greater than the internal magnetic field from nuclear spin does. These results provide a design criterion for construction of multiple spin qubit based on g-tensor engineering.
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Affiliation(s)
- Tsutomu Yamabayashi
- Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Yoji Horii
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara, 630-8506, Japan
| | - Zhao-Yang Li
- School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Masahiro Yamashita
- Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba Aoba-ku, Sendai, Miyagi, 980-8578, Japan
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, P. R. China
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2
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Riesen H. Ultra-slow electron spin-lattice relaxation in a low magnetic field enables massive optical spin polarization in the 4A 2ground state of Cr 3+in ruby. J Phys Condens Matter 2022; 34:155701. [PMID: 35045409 DOI: 10.1088/1361-648x/ac4cea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
Ruby (α-Al2O3doped with Cr3+) has been an archetypal material in the development of optical spectroscopy of the solid state for the last 150 years and was the first material that was demonstrated to lase. Notwithstanding the vast literature on ruby, one effect was somehow missed: in a magnetic fieldB∥c∼ 235 mT, the spin-lattice relaxation timeT1for the |+3/2⟩ level in the4A2ground state is massively lengthened to ∼12 s at 1.4 K as demonstrated in this study. This very long relaxation time enables optical pumping of the |+3/2⟩ level via theR1(±1/2) lines and a considerable +3/2 spin polarization of ∼95% is readily achieved. The observed magnetic field dependence can be quantitatively described using the one-phonon relaxation process.
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Affiliation(s)
- Hans Riesen
- School of Science, The University of New South Wales, Canberra ACT 2600, Australia
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3
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Lin M, Breukels V, Scheenen TWJ, Paulusse JMJ. Dynamic Nuclear Polarization of Silicon Carbide Micro- and Nanoparticles. ACS Appl Mater Interfaces 2021; 13:30835-30843. [PMID: 34170657 PMCID: PMC8289227 DOI: 10.1021/acsami.1c07156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/13/2021] [Indexed: 06/13/2023]
Abstract
Two dominant crystalline phases of silicon carbide (SiC): α-SiC and β-SiC, differing in size and chemical composition, were investigated regarding their potential for dynamic nuclear polarization (DNP). 29Si nuclei in α-SiC micro- and nanoparticles with sizes ranging from 650 nm to 2.2 μm and minimal oxidation were successfully hyperpolarized without the use of free radicals, while β-SiC samples did not display appreciable degrees of polarization under the same polarization conditions. Long T1 relaxation times in α-SiC of up to 1600 s (∼27 min) were recorded for the 29Si nuclei after 1 h of polarization at a temperature of 4 K. Interestingly, these promising α-SiC particles allowed for direct hyperpolarization of both 29Si and 13C nuclei, resulting in comparably strong signal amplifications. Moreover, the T1 relaxation time of 13C nuclei in 750 nm-sized α-SiC particles was over 33 min, which far exceeds T1 times of conventional 13C DNP probes with values in the order of 1-2 min. The present work demonstrates the feasibility of DNP on SiC micro- and nanoparticles and highlights their potential as hyperpolarized magnetic resonance imaging agents.
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Affiliation(s)
- Min Lin
- Department
of Biomolecular Nanotechnology, MESA+ Institute for Nanotechnology,
Faculty of Science and Technology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Vincent Breukels
- Department
of Medical Imaging, Radboud University Medical
Center, Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Tom W. J. Scheenen
- Department
of Medical Imaging, Radboud University Medical
Center, Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Jos M. J. Paulusse
- Department
of Biomolecular Nanotechnology, MESA+ Institute for Nanotechnology,
Faculty of Science and Technology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- Department
of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen,
P.O. Box 30.001, 9700 RB Groningen, The Netherlands
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4
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Horii Y, Katoh K, Miyazaki Y, Damjanović M, Sato T, Ungur L, Chibotaru LF, Breedlove BK, Nakano M, Wernsdorfer W, Yamashita M. Coexistence of Spin-Lattice Relaxation and Phonon-Bottleneck Processes in Gd III -Phthlocyaninato Triple-Decker Complexes under Highly Diluted Conditions. Chemistry 2020; 26:8076-8082. [PMID: 32057140 DOI: 10.1002/chem.201905796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Indexed: 11/06/2022]
Abstract
Gd3+ complexes have been shown to undergo unusual slow magnetic relaxation processes similar to those of single-molecule magnets (SMMs), even though Gd3+ does not exhibit strong magnetic anisotropy. To reveal the origin of the slow magnetic relaxation of Gd3+ complexes, we have investigated the magnetic properties and heat capacities of two Gd3+ -phthalocyaninato triple-decker complexes, one of which has intramolecular Gd3+ -Gd3+ interactions and the other does not. It was found that the Gd3+ -Gd3+ interactions accelerate the magnetic relaxation processes. In addition, magnetically diluted samples, prepared by doping a small amount of the Gd3+ complexes into a large amount of diamagnetic Y3+ complexes, underwent dual magnetic relaxation processes. A detailed dynamic magnetic analysis revealed that the coexistence of spin-lattice relaxation and phonon-bottleneck processes is the origin of the dual magnetic relaxation processes.
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Affiliation(s)
- Yoji Horii
- Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Keiichi Katoh
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Yuji Miyazaki
- Research Center for Thermal and Entropic Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan
| | - Marko Damjanović
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Tetsu Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Liviu F Chibotaru
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, 3001, Leuven, Belgium
| | - Brian K Breedlove
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Motohiro Nakano
- Research Center for Thermal and Entropic Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan
| | - Wolfgang Wernsdorfer
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Masahiro Yamashita
- Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.,School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
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5
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Parslow ST, Almazrouei NK, Newton MI, Dye ER, Morris RH. A preliminary study of milk powder hydration using TEDSpiL continuous wave NMR. Magn Reson Chem 2019; 57:695-699. [PMID: 30707775 DOI: 10.1002/mrc.4845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
Moisture content of foodstuffs are typically assessed by Titration or Near Infrared Spectroscopy, which are labour-intensive as a manual measurement or costly when automated. Magnetic resonance offers a method for moisture evaluation but is also normally costly. In this work, we revisit Look and Locker's "Tone Burst" experiment with a marginal oscillator to evaluate moisture content of powdered-skimmed milk subjected to increased humidity. We refer to this technique as the Transient Effect Determination of Spin-Lattice (TEDSpiL) relaxation times. Moisture content in the samples ranged from 0-12% as determined from the weight gained by the dry powder when re-suspended in water to reach a concentration of 40% w/v. The relaxation properties of re-hydrated samples were measured with a CW NMR sensor. Solutions made up from powders with a higher retained moisture content provided lower measured relaxation values providing a method of measuring the moisture content of the powder. This technique provides a moisture measurement in under 5∼s compared with several minutes for the equivalent pulsed method using low-field hardware.
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Affiliation(s)
- Steven T Parslow
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Najlaa K Almazrouei
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Michael I Newton
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Elizabeth R Dye
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Robert H Morris
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
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6
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Georgi J, Metere R, Jäger C, Morawski M, Möller HE. Influence of the extracellular matrix on water mobility in subcortical gray matter. Magn Reson Med 2018; 81:1265-1279. [PMID: 30276849 DOI: 10.1002/mrm.27459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/12/2018] [Accepted: 06/29/2018] [Indexed: 11/12/2022]
Abstract
PURPOSE Water mobility in tissues is related to the microstructure that modulates diffusion and spin relaxation. Previous work has shown that the extracellular matrix (ECM) impacts water diffusion in cartilage. To investigate if similar contributions to image contrast exist for brain, which is characterized by a substantially lower ECM content, diffusion and relaxation were studied in fixed samples from goat and human thalamus before and after enzymatic digestion of ECM compounds. Selected experiments in human corpus callosum were included for comparing subcortical gray matter and white matter. METHODS Digestion of matrix components was achieved by treatment with hyaluronidase. Nonlocalized pulsed field gradient measurements were performed with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>b</mml:mi></mml:math> values between 0.6 and 18,000 s/mm2 at 3T and temperatures between 0°C and 20°C, in addition to T1 and T2 relaxation measurements. The data were fitted to multiexponential models to account for different water compartments. After the measurements, the samples were sliced and stained for ECM-sensitive markers to verify efficient digestion. RESULTS Microstructural alterations associated with hyaluronan digestion did not lead to measurable effects on water diffusion or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:math> . However, T1 of the main relaxographic component, attributed to intra-/extracellular water, decreased by 7%. CONCLUSION Investigations with very strong gradients did not reveal a detectable effect on water diffusion or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:math> after hyaluronan removal, indicating that the brain ECM content is too low to produce a detectable effect. The subtle alteration of T1 upon hyaluronidase treatment might reflect a modulation of intercompartmental water exchange properties.
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Affiliation(s)
- Jakob Georgi
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Riccardo Metere
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Carsten Jäger
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Paul Flechsig Institute of Brain Research, University of Leipzig, Germany
| | - Markus Morawski
- Paul Flechsig Institute of Brain Research, University of Leipzig, Germany
| | - Harald E Möller
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Felix Bloch Institute for Solid State Physics, University of Leipzig, Germany
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7
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Beckmann PA, Ford J, Malachowski WP, McGhie AR, Moore CE, Rheingold AL, Sloan GJ, Szewczyk ST. Proton Spin-Lattice Relaxation in Organic Molecular Solids: Polymorphism and the Dependence on Sample Preparation. Chemphyschem 2018; 19:2423-2436. [PMID: 29956438 DOI: 10.1002/cphc.201800237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Indexed: 11/07/2022]
Abstract
We report solid-state nuclear magnetic resonance 1 H spin-lattice relaxation, single-crystal X-ray diffraction, powder X-ray diffraction, field emission scanning electron microscopy, and differential scanning calorimetry in solid samples of 2-ethylanthracene (EA) and 2-ethylanthraquinone (EAQ) that have been physically purified in different ways from the same commercial starting compounds. The solid-state 1 H spin-lattice relaxation is always non-exponential at high temperatures as expected when CH3 rotation is responsible for the relaxation. The 1 H spin-lattice relaxation experiments are very sensitive to the "several-molecule" (clusters) structure of these van der Waals molecular solids. In the three differently prepared samples of EAQ, the relaxation also becomes very non-exponential at low temperatures. This is very unusual and the decay of the nuclear magnetization can be fitted with both a stretched exponential and a double exponential. This unusual result correlates with the powder X-ray diffractometry results and suggests that the anomalous relaxation is due to crystallites of two (or more) different polymorphs (concomitant polymorphism).
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Affiliation(s)
- Peter A Beckmann
- Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania, USA
| | - Jamie Ford
- Nanoscale Characterization Facility Singh Center for Nanotechnology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Andrew R McGhie
- Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Curtis E Moore
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Gilbert J Sloan
- Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven T Szewczyk
- Department of Materials Science and Engineering School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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8
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Ferraz A, Zhang J, Sebastião PJ, Ribeiro AC, Dong RY. Proton and deuterium nuclear spin relaxation study of the SmA and SmC* phases of BP8Cl-d17 : a self-consistent analysis. Magn Reson Chem 2014; 52:546-555. [PMID: 25132369 DOI: 10.1002/mrc.4107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/01/2014] [Accepted: 06/18/2014] [Indexed: 06/03/2023]
Abstract
A self-consistent analysis of proton and deuterium nuclear spin relaxation times in the smectic phases of a partially deuterated smectogen is presented here. Proton spin-lattice relaxation times T(1Z) were measured as a function of Larmor frequency over a range of 1 kHz to 300 MHz at selected temperatures. Deuterium spin relaxation times T(1Z) and T(1Q) were measured as a function of temperature at two different magnetic fields in the smectic A phase. The deuterium data provide dynamic parameters such as rotational diffusion constants and internal jump rates as well as the nematic order parameter S. The proton data are analyzed using a number of relaxation mechanisms, one of which is the molecular reorientation. It is found helpful in these latter analyses to use the nematic order parameter and to fix the contribution from molecular reorientations determined by the deuterium spin relaxation. The fits to the proton T(1) frequency and temperature dispersions by the remaining relaxation mechanisms such as layer undulations and translational self-diffusion will be discussed for the smectic A and chiral smectic C phases.
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Affiliation(s)
- A Ferraz
- Department of Physics, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal; Centro de Física da Matéria Condensada, Av. Prof. Gama Pinto 2, 1649-003 Lisbon, Portugal
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9
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Marco-Rius I, Bohndiek SE, Kettunen MI, Larkin TJ, Basharat M, Seeley C, Brindle KM. Quantitation of a spin polarization-induced nuclear Overhauser effect (SPINOE) between a hyperpolarized (13) C-labeled cell metabolite and water protons. Contrast Media Mol Imaging 2014; 9:182-6. [PMID: 24523064 PMCID: PMC4265858 DOI: 10.1002/cmmi.1556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/25/2013] [Accepted: 06/22/2013] [Indexed: 01/19/2023]
Abstract
The spin polarization-induced nuclear Overhauser effect (SPINOE) describes the enhancement of spin polarization of solvent nuclei by the hyperpolarized spins of a solute. In this communication we demonstrate that SPINOEs can be observed between [1,4-(13) C2 ]fumarate, hyperpolarized using the dissolution dynamic nuclear polarization technique, and solvent water protons. We derive a theoretical expression for the expected enhancement and demonstrate that this fits well with experimental measurements. Although the magnitude of the effect is relatively small (around 2% measured here), the SPINOE increases at lower field strengths, so that at clinically relevant magnetic fields (1.5-3 T) it may be possible to track the passage through the circulation of a bolus containing a hyperpolarized (13) C-labeled substrate through the increase in solvent water (1) H signal.
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Affiliation(s)
- Irene Marco-Rius
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Sarah E Bohndiek
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Mikko I Kettunen
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Timothy J Larkin
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Meer Basharat
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Colm Seeley
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
| | - Kevin M Brindle
- Department of Biochemistry, University of Cambridge and Cancer Research UK, Cambridge Research InstituteCambridge, UK
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10
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Abstract
(2)H NMR reveals two dynamic crossovers of supercooled water in nanoscopic (∼2 nm) confinement. At ∼225 K, a dynamic crossover of liquid water is accompanied by formation of a fraction of solid water. Therefore, we do not attribute the effect to a liquid-liquid phase transition but rather to a change from bulk-like to interface-dominated dynamics. Moreover, we argue that the α process and β process are observed in experiments above and below this temperature, respectively. Upon cooling through a dynamic crossover at ∼175 K, the dynamics of the liquid fraction becomes anisotropic and localized, implying solidification of the corresponding water network, most probably, during a confinement-affected glass transition.
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Affiliation(s)
- M Sattig
- Institut für Festkörperphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
| | - M Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
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11
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Ji Y, Sullivan NS, Tang Y, Hamida JA. Interactions and Diffusion of Methane and Hydrogen in Microporous Structures: Nuclear Magnetic Resonance (NMR) Studies. Materials (Basel) 2013; 6:2464-2482. [PMID: 28809284 PMCID: PMC5458947 DOI: 10.3390/ma6062464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/04/2013] [Accepted: 06/05/2013] [Indexed: 06/07/2023]
Abstract
Measurements of nuclear spin relaxation times over a wide temperature range have been used to determine the interaction energies and molecular dynamics of light molecular gases trapped in the cages of microporous structures. The experiments are designed so that, in the cases explored, the local excitations and the corresponding heat capacities determine the observed nuclear spin-lattice relaxation times. The results indicate well-defined excitation energies for low densities of methane and hydrogen deuteride in zeolite structures. The values obtained for methane are consistent with Monte Carlo calculations of A.V. Kumar et al. The results also confirm the high mobility and diffusivity of hydrogen deuteride in zeolite structures at low temperatures as observed by neutron scattering.
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Affiliation(s)
- Yu Ji
- Department of Physics, University of Florida, Gainesville, FL 32611, USA.
| | - Neil S Sullivan
- Department of Physics, University of Florida, Gainesville, FL 32611, USA.
| | - Yibing Tang
- Department of Physics, University of Florida, Gainesville, FL 32611, USA.
| | - Jaha A Hamida
- Department of Physics, University of Florida, Gainesville, FL 32611, USA.
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12
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Wang G, El-Sharkawy AM, Edelstein WA, Schär M, Bottomley PA. Measuring T₂ and T₁, and imaging T₂ without spin echoes. J Magn Reson 2012; 214:273-280. [PMID: 22197502 PMCID: PMC3304500 DOI: 10.1016/j.jmr.2011.11.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 11/18/2011] [Accepted: 11/24/2011] [Indexed: 05/31/2023]
Abstract
During adiabatic excitation, the nuclear magnetization in the transverse plane is subject to T(2) (spin-spin) relaxation, depending on the pulse length τ. Here, this property is exploited in a method of measuring T(2) using the ratio of NMR signals acquired with short and long-duration self-refocusing adiabatic pulses, without spin-echoes. This Dual-τ method is implemented with B(1)-insensitive rotation (BIR-4) pulses. It is validated theoretically with Bloch equation simulations independent of flip-angle, and experimentally in phantoms. Dual-τT(2) measurements are most accurate at short T(2) where results agree with standard spin-echo measures to within 10% for T(2) ≤ 100 ms. Dual-τ MRI performed with a long 0° BIR-4 pre-pulse provides quantitative T(2) imaging of phantoms and the human foot while preserving desired contrast and functional properties of the rest of the MRI sequence. A single 0° BIR-4 pre-pulse can provide T(2) contrast-weighted MRI and serve as a "T(2)-prep" sequence with a lower B(1) requirement than prior approaches. Finally, a Tri-τ experiment is introduced in which both τ and flip-angle are varied, enabling measurement of T(2), T(1) and signal intensity in just three acquisitions if flip-angles are well-characterized. These new methods can potentially save time and simplify relaxation measurements and/or contrast-weighted NMR and MRI.
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Affiliation(s)
- G Wang
- Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA
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13
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Diakova G, Goddard Y, Korb JP, Bryant RG. Water-proton-spin-lattice-relaxation dispersion of paramagnetic protein solutions. J Magn Reson 2011; 208:195-203. [PMID: 21134772 PMCID: PMC3026090 DOI: 10.1016/j.jmr.2010.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/29/2010] [Accepted: 11/03/2010] [Indexed: 05/23/2023]
Abstract
The paramagnetic contributions to water-proton-spin-lattice relaxation rate constants in protein systems spin-labeled with nitroxide radicals were re-examined. As noted by others, the strength of the dipolar coupling between water protons and the protein-bound nitroxide radical often appears to be larger than physically reasonable when the relaxation is assumed to be controlled by 3-dimensional diffusive processes in the vicinity of the spin label. We examine the effects of the surface in biasing the diffusive exploration of the radical region and derive a relaxation model that incorporates 2-dimensional dynamics at the interfacial layer. However, we find that the local 2-dimensional dynamics changes the shape of the relaxation dispersion profile but does not necessarily reproduce the low-field relaxation efficiency found by experiment. We examine the contributions of long-range dipolar couplings between the paramagnetic center and protein-bound-water molecules and find that the contributions from these several long range couplings may be competitive with translational contributions because the correlation time for global rotation of the protein is approximately 1000 times longer than that for the diffusive motion of water at the interfacial region. As a result the electron-proton dipolar coupling to rare protein-bound-water-molecule protons may be significant for protein systems that accommodate long-lived-water molecules. Although the estimate of local diffusion coefficients is not seriously compromised because it derives from the Larmor frequency dependence, these several contributions confound efforts to fit relaxation data quantitatively with unique models.
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Affiliation(s)
| | | | - Jean-Pierre Korb
- Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128, Palaiseau, France
| | - Robert G. Bryant
- Chemistry Department University of Virginia Charlottesville, VA, USA
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Chu S, Maltsev S, Emwas AH, Lorigan GA. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers. J Magn Reson 2010; 207:89-94. [PMID: 20851650 PMCID: PMC2978330 DOI: 10.1016/j.jmr.2010.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 08/11/2010] [Accepted: 08/18/2010] [Indexed: 05/20/2023]
Abstract
A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC) phospholipid bilayers as paramagnetic moieties and the resulting enhancements of the longitudinal relaxation (T₁) times of ³¹P nuclei on the surface of the bilayers were measured by a standard inversion recovery pulse sequence. The ³¹P NMR spin-lattice relaxation times decrease steadily as the DOXYL spin label moves closer to the surface as well as the concentration of the spin-labeled lipids increase. The enhanced relaxation vs. the position and concentration of spin-labels indicate that PRE induced by the DOXYL spin label are significant to determine longer distances over the whole range of the membrane depths. When these data were combined with estimated correlation times τ(c), the r⁻⁶-weighted, time-averaged distances between the spin-labels and the ³¹P nuclei on the membrane surface were estimated. The application of using this solid-state NMR PRE approach coupled with site-directed spin labeling (SDSL) may be a powerful method for measuring membrane protein immersion depth.
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Affiliation(s)
- Shidong Chu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - Sergey Maltsev
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - A-H Emwas
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
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Thurber KR, Yau WM, Tycko R. Low-temperature dynamic nuclear polarization at 9.4 T with a 30 mW microwave source. J Magn Reson 2010; 204:303-13. [PMID: 20392658 PMCID: PMC2874615 DOI: 10.1016/j.jmr.2010.03.016] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 03/11/2010] [Accepted: 03/18/2010] [Indexed: 05/05/2023]
Abstract
Dynamic nuclear polarization (DNP) can provide large signal enhancements in nuclear magnetic resonance (NMR) by transfer of polarization from electron spins to nuclear spins. We discuss several aspects of DNP experiments at 9.4 T (400 MHz resonant frequency for (1)H, 264 GHz for electron spins in organic radicals) in the 7-80K temperature range, using a 30 mW, frequency-tunable microwave source and a quasi-optical microwave bridge for polarization control and low-loss microwave transmission. In experiments on frozen glycerol/water doped with nitroxide radicals, DNP signal enhancements up to a factor of 80 are observed (relative to (1)H NMR signals with thermal equilibrium spin polarization). The largest sensitivity enhancements are observed with a new triradical dopant, DOTOPA-TEMPO. Field modulation with a 10 G root-mean-squared amplitude during DNP increases the nuclear spin polarizations by up to 135%. Dependencies of (1)H NMR signal amplitudes, nuclear spin relaxation times, and DNP build-up times on the dopant and its concentration, temperature, microwave power, and modulation frequency are reported and discussed. The benefits of low-temperature DNP can be dramatic: the (1)H spin polarization is increased approximately 1000-fold at 7 K with DNP, relative to thermal polarization at 80K.
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Affiliation(s)
- Kent R. Thurber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
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16
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Goddard YA, Korb JP, Bryant RG. Water molecule contributions to proton spin-lattice relaxation in rotationally immobilized proteins. J Magn Reson 2009; 199:68-74. [PMID: 19394883 PMCID: PMC2794799 DOI: 10.1016/j.jmr.2009.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 04/01/2009] [Accepted: 04/04/2009] [Indexed: 05/23/2023]
Abstract
Spin-lattice relaxation rates of protein and water protons in dry and hydrated immobilized bovine serum albumin were measured in the range of (1)H Larmor frequency from 10 kHz to 30 MHz at temperatures from 154 to 302 K. The water proton spin-lattice relaxation reports on that of protein protons, which causes the characteristic power law dependence on the magnetic field strength. Isotope substitution of deuterium for hydrogen in water and studies at different temperatures expose three classes of water molecule dynamics that contribute to the spin-lattice relaxation dispersion profile. At 185 K, a water (1)H relaxation contribution derives from reorientation of protein-bound molecules that are dynamically uncoupled from the protein backbone and is characterized by a Lorentzian function. Bound-water-molecule motions that can be dynamically uncoupled or coupled to the protein fluctuations make dominant contributions at higher temperatures as well. Surface water translational diffusion that is magnetically two-dimensional makes relaxation contributions at frequencies above 10 MHz. It is shown using isotope substitution that the exponent of the power law of the water signal in hydrated immobilized protein systems is the same as that for protons in lyophilized proteins over four orders of magnitude in the Larmor frequency, which implies that changes in the protein structure associated with hydration do not affect the (1)H spin relaxation.
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Affiliation(s)
- Yanina A. Goddard
- Chemistry Department, University of Virginia, Charlottesville, VA, USA 22904
| | - Jean-Pierre Korb
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128 Palaiseau, France
| | - Robert G. Bryant
- Chemistry Department, University of Virginia, Charlottesville, VA, USA 22904
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Thurber KR, Tycko R. Biomolecular solid state NMR with magic-angle spinning at 25K. J Magn Reson 2008; 195:179-86. [PMID: 18922715 PMCID: PMC2632798 DOI: 10.1016/j.jmr.2008.09.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/19/2008] [Accepted: 09/10/2008] [Indexed: 05/05/2023]
Abstract
A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25K using roughly 3 L/h of liquid helium, while the 4-mm diameter rotor spins at 6.7 kHz with good stability (+/-5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature (13)C NMR data for two biomolecular samples, namely the peptide Abeta(14-23) in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin-lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and (13)C MAS NMR linewidths are discussed.
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Affiliation(s)
| | - Robert Tycko
- corresponding author: Dr. Robert Tycko, National Institutes of Health, Building 5, Room 112, Bethesda, MD 20892-0520. phone: 301-402-8272. fax: 301-496-0825. e-mail:
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Sato H, Bottle SE, Blinco JP, Micallef AS, Eaton GR, Eaton SS. Electron spin-lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids. J Magn Reson 2008; 191:66-77. [PMID: 18166493 PMCID: PMC2671210 DOI: 10.1016/j.jmr.2007.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 12/07/2007] [Accepted: 12/07/2007] [Indexed: 05/12/2023]
Abstract
Electron spin-lattice relaxation rates, 1/T1, at X-band of nitroxyl radicals (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidin-1-oxyl and 3-carbamoyl-2,2,5,5-tetramethylpyrrolin-1-oxyl) in glass-forming solvents (decalin, glycerol, 3-methylpentane, o-terphenyl, 1-propanol, sorbitol, sucrose octaacetate, and 1:1 water:glycerol) at temperatures between 100 and 300K were measured by long-pulse saturation recovery to investigate the relaxation processes in slow-to-fast tumbling regimes. A subset of samples was also studied at lower temperatures or at Q-band. Tumbling correlation times were calculated from continuous wave lineshapes. Temperature dependence and isotope substitution (2H and 15N) were used to distinguish the contributions of various processes. Below about 100K relaxation is dominated by the Raman process. At higher temperatures, but below the glass transition temperature, a local mode process makes significant contributions. Above the glass transition temperature, increased rates of molecular tumbling modulate nuclear hyperfine and g anisotropy. The contribution from spin rotation is very small. Relaxation rates at X-band and Q-band are similar. The dependence of 1/T1 on tumbling correlation times fits better with the Cole-Davidson spectral density function than with the Bloembergen-Purcell-Pound model.
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Affiliation(s)
- Hideo Sato
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
| | - Steven E. Bottle
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - James P. Blinco
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - Aaron S. Micallef
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
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Abstract
The purpose of this paper is to review in vivo NMR experiments [1, 2] on a transplantable tumor in mice and to discuss the feasibility of using noninvasive NMR for cancer detection in humans.
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Affiliation(s)
- I D Weisman
- Institute for Materials Research, National Bureau of Standards, Washington, D.C. 20234
| | - L H Bennett
- Institute for Materials Research, National Bureau of Standards, Washington, D.C. 20234
| | | | - D E Henson
- Laboratory of Pathology, National Cancer Institute, Bethesda, Md. 20014
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Abstract
Measurements of the water proton spinlattice relaxation (T(1)) in 106 human tumors confirms earlier results with animals [Damadian, R. (1971) Science 171, 1151-1153]. T(1) of all the tumors studied were significantly longer than T(1) of the corresponding normal tissues. Mean standard error and range were reported for T(1) of every human organ and for all the tumor groups studied. The technique is now ready for use by pathologists as an adjunct to present methods of diagnosing malignancy.
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