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Moutal N, Maximov II, Grebenkov DS. Probing Surface-to-Volume Ratio of an Anisotropic Medium by Diffusion NMR with General Gradient Encoding. IEEE TRANSACTIONS ON MEDICAL IMAGING 2019; 38:2507-2522. [PMID: 30843822 DOI: 10.1109/tmi.2019.2902957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Since the seminal paper by Mitra et al., diffusion MR has been widely used in order to estimate surface-to-volume ratios. In this paper, we generalize Mitra's formula for arbitrary diffusion encoding waveforms, including recently developed q-space trajectory encoding sequences. We show that the surface-to-volume ratio can be significantly misestimated using the original Mitra's formula without taking into account the applied gradient profile. In order to obtain more accurate estimation in anisotropic samples, we propose an efficient and robust optimization algorithm to design diffusion gradient waveforms with prescribed features. Our results are supported by Monte Carlo simulations.
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2
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Li C, Zhan H, Yan J, Hao M, Lin E, Huang Y, Chen Z. A pure shift and spin echo based approach for high-resolution diffusion-ordered NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 305:209-218. [PMID: 31310918 DOI: 10.1016/j.jmr.2019.07.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/06/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
Diffusion-ordered NMR spectroscopy (DOSY) can be used for separating mixture components according to their individual diffusion behaviors, thus offering a powerful tool for the analysis of compound mixtures. However, conventional DOSY experiments generally encounter the problem of limited resolution in the spectral domain, particularly for applications to complex mixtures that contains crowed resonances in 1D NMR. In addition, chemical exchange effects, bringing about spurious component signals, pose another limitation for interpreting DOSY measurements. Here, a general DOSY method is proposed based on pure shift extraction and spin echo evolution to obtain high-resolution 2D DOSY spectra, along with the suppression on effects of chemical exchange and J coupling. Both theoretical analyses and experimental results suggest that the proposed method is useful for high-resolution DOSY measurements on complex mixtures that contains crowded or even overlapped NMR resonances and exchanging spin systems.
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Affiliation(s)
- Chen Li
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Haolin Zhan
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Jin Yan
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Mengyou Hao
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Enping Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Yuqing Huang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China.
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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3
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Mitchell J. Magnetic resonance diffusion measurements of droplet size in drilling fluid emulsions on a benchtop instrument. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2018.12.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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4
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Diffusivity of crude oils contained in macroporous medium: 1 H NMR study. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.03.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Lipidomics, Biomarkers, and Schizophrenia: A Current Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 965:265-290. [PMID: 28132184 DOI: 10.1007/978-3-319-47656-8_11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipidomics is a lipid-targeted metabolomics approach aiming at comprehensive analysis of lipids in biological systems. Recent technological progresses in mass spectrometry, nuclear magnetic resonance spectroscopy, and chromatography have significantly enhanced the developments and applications of metabolic profiling of lipids in more complex biological samples. As many diseases reveal a notable change in lipid profiles compared with that of healthy people, lipidomics have also been broadly introduced to scientific research on diseases. Exploration of lipid biochemistry by lipidomics approach will not only provide insights into specific roles of lipid molecular species in health and disease, but it will also support the identification of potential biomarkers for establishing preventive or therapeutic approaches for human health. This chapter aims to illustrate how lipidomics can contribute for understanding the biological mechanisms inherent to schizophrenia and why lipids are relevant biomarkers of schizophrenia. The application of lipidomics in clinical studies has the potential to provide new insights into lipid profiling and pathophysiological mechanisms underlying schizophrenia. The future perspectives of lipidomics in mental disorders are also discussed herein.
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Duschl M, Pohlmeier A, Brox TI, Galvosas P, Vereecken H. Effect of magnetic pore surface coating on the NMR relaxation and diffusion signal in quartz sand. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:975-984. [PMID: 27420565 DOI: 10.1002/mrc.4486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 07/04/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Magnetic impurities are ubiquitous in natural porous media such as sand and soil. They generate internal magnetic field gradients because of increased magnetic susceptibility differences between solid and liquid phase in the pore space and because of the presence of magnetic centers. These internal gradients accelerate NMR relaxation rates and thus might limit the possibility of pore space characterization using NMR. In this study, we investigate the effects of coating the surface of natural sands by the antiferromagnetic iron oxyhydroxide goethite on NMR relaxation and diffusion properties. We found a non-quadratic dependence of the relaxation time distributions on the echo time indicating that the relaxation experiments were not performed in the fast diffusion limit, while the weak dependence on the external magnetic field strength is explained by the preponderance of the surface relaxation over the effect of diffusion in internal gradients. The surface to volume ratio of the pore space, determined by NMR diffusimetry ((S/V)NMR ) remains approximately constant, whereas the same quantity, determined from gas adsorption ((S/V)BET ) increases proportional to the coating density. This is because gas adsorption measures surface roughness on sub-nanometer scale, whereas NMR diffusimetry averages over structures smaller than few microns. This has consequences for the calculation of the surface relaxivities. The usage of the (S/V)NMR leads to constant values, whereas the usage of (S/V)BET leads to apparently decreasing relaxivities with increasing coating, which is unrealistic. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Markus Duschl
- Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Andreas Pohlmeier
- Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Timothy I Brox
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Petrik Galvosas
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Harry Vereecken
- Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
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7
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Laun FB, Kuder TA, Zong F, Hertel S, Galvosas P. Symmetry of the gradient profile as second experimental dimension in the short-time expansion of the apparent diffusion coefficient as measured with NMR diffusometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:10-19. [PMID: 26254733 DOI: 10.1016/j.jmr.2015.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/30/2015] [Accepted: 07/03/2015] [Indexed: 06/04/2023]
Abstract
The time-dependent apparent diffusion coefficient as measured by pulsed gradient NMR can be used to estimate parameters of porous structures including the surface-to-volume ratio and the mean curvature of pores. In this work, the short-time diffusion limit and in particular the influence of the temporal profile of diffusion gradients on the expansion as proposed by Mitra et al. (1993) is investigated. It is shown that flow-compensated waveforms, i.e. those whose first moment is zero, are blind to the term linear in observation time, which is the term that is proportional to mean curvature and surface permeability. A gradient waveform that smoothly interpolates between flow-compensated and bipolar waveform is proposed and the degree of flow-compensation is used as a second experimental dimension. This two-dimensional ansatz is shown to yield an improved precision when characterizing the confining domain. This technique is demonstrated with simulations and in experiments performed with cylindrical capillaries of 100 μm radius.
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Affiliation(s)
- Frederik Bernd Laun
- Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69121 Heidelberg, Germany.
| | - Tristan Anselm Kuder
- Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69121 Heidelberg, Germany.
| | - Fangrong Zong
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
| | - Stefan Hertel
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
| | - Petrik Galvosas
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
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Goossens K, Prior M, Pacheco V, Willbold D, Müllen K, Enderlein J, Hofkens J, Gregor I. Accurate Diffusion Coefficients of Organosoluble Reference Dyes in Organic Media Measured by Dual-Focus Fluorescence Correlation Spectroscopy. ACS NANO 2015; 9:7360-7373. [PMID: 26144863 DOI: 10.1021/acsnano.5b02371] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Dual-focus fluorescence correlation spectroscopy (2fFCS) is a versatile method to determine accurate diffusion coefficients of fluorescent species in an absolute, reference-free manner. Whereas (either classical or dual-focus) FCS has been employed primarily in the life sciences and thus in aqueous environments, it is increasingly being used in materials chemistry, as well. These measurements are often performed in nonaqueous media such as organic solvents. However, the diffusion coefficients of reference dyes in organic solvents are not readily available. For this reason we determined the translational diffusion coefficients of several commercially available organosoluble fluorescent dyes by means of 2fFCS. The selected dyes and organic solvents span the visible spectrum and a broad range of refractive indices, respectively. The diffusion coefficients can be used as absolute reference values for the calibration of experimental FCS setups, allowing quantitative measurements to be performed. We show that reliable information about the hydrodynamic dimensions of the fluorescent species (including noncommercial compounds) within organic media can be extracted from the 2fFCS data.
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Affiliation(s)
- Karel Goossens
- †KU Leuven, Department of Chemistry, Celestijnenlaan 200F (PO Box 2404), 3001 Heverlee, Belgium
- ‡Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), 101-dong, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea
| | - Mira Prior
- §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Victor Pacheco
- ⊥Research Centre Jülich, Institute of Complex Systems: Structural Biochemistry (ICS-6), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- ∥Albert Ludwigs University, Institute for Macromolecular Chemistry, Hermann-Staudinger-Haus, Stefan-Meier-Straße 31, 79104 Freiburg, Germany
| | - Dieter Willbold
- ⊥Research Centre Jülich, Institute of Complex Systems: Structural Biochemistry (ICS-6), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- #Heinrich Heine University, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Klaus Müllen
- ∇Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Jörg Enderlein
- §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Johan Hofkens
- †KU Leuven, Department of Chemistry, Celestijnenlaan 200F (PO Box 2404), 3001 Heverlee, Belgium
| | - Ingo Gregor
- §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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9
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In vivo measurement of the size of oil bodies in plant seeds using a simple and robust pulsed field gradient NMR method. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:121-9. [DOI: 10.1007/s00249-015-1007-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/18/2014] [Accepted: 01/13/2015] [Indexed: 11/29/2022]
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10
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Chevalier T, Faure PF, Chevalier C, Coussot P, Rodts S. Velocity distributions in confined flows of some complex fluids: sequence, sample and hardware issues. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 245:156-170. [PMID: 24934338 DOI: 10.1016/j.jmr.2014.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 06/03/2023]
Abstract
The present work addresses the problem of using Pulsed Field Gradient (PFG) experiments to measure velocity probability density functions and/or distributions in restricted flows, without being subjected to the blurring due to diffusive molecular motions. It especially focuses on two important classes of complex yield-stress fluids, i.e. water based colloidal suspensions or polymeric gels, and concentrated emulsions. Taking into account the many constraints owing to fluid diffusive properties, flow rate, hardware characteristics and pore size, it is found that the existence of suitable and optimised sequence parameters can be discussed in a graphical way. To do so, it also shown that Murday and Cotts formula describing diffusion inside emulsion droplets can be efficiently approximated by means of a set of asymptotic expressions. Different tuning regimes are identified for both kind of fluids, highlighting the influence of each of the various constraints on measuring possibilities. A method is given to build quantitative diagrams indicating pore sizes and flow rates allowing pure velocity assessment for a given fluid and Nuclear Magnetic Resonance (NMR) hardware. Measurements are found to be mainly constrained by fluid self-diffusivity and microstructure at low flow rates, and hardware characteristics at high flow rates. Although high gradient strengths can be made necessary to decrease achievable velocities and pore sizes in some specific cases, low gradient systems turn out suitable in many situations thanks to optimised sequence tuning. Due to their larger size, the latter also appear to offer the widest variety of workable experimental conditions. The use of these results is finally exemplified on the practical case of an emulsion flow in a model porous system.
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Affiliation(s)
- T Chevalier
- Université Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, F-77420 Marne-la-Vallée, France(1)
| | - P F Faure
- Université Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, F-77420 Marne-la-Vallée, France(1)
| | - C Chevalier
- Université Paris Est, IFSTTAR, Département Géotechnique Eau et Risques, F-77420 Marne-la-Vallée, France
| | - P Coussot
- Université Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, F-77420 Marne-la-Vallée, France(1)
| | - S Rodts
- Université Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, F-77420 Marne-la-Vallée, France(1).
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11
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Sigmund EE, Novikov DS, Sui D, Ukpebor O, Baete S, Babb JS, Liu K, Feiweier T, Kwon J, Mcgorty K, Bencardino J, Fieremans E. Time-dependent diffusion in skeletal muscle with the random permeable barrier model (RPBM): application to normal controls and chronic exertional compartment syndrome patients. NMR IN BIOMEDICINE 2014; 27:519-28. [PMID: 24610770 PMCID: PMC3980069 DOI: 10.1002/nbm.3087] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 12/13/2013] [Accepted: 01/10/2014] [Indexed: 05/11/2023]
Abstract
The purpose of this work was to carry out diffusion tensor imaging (DTI) at multiple diffusion times Td in skeletal muscle in normal subjects and chronic exertional compartment syndrome (CECS) patients and analyze the data with the random permeable barrier model (RPBM) for biophysical specificity. Using an institutional review board approved HIPAA-compliant protocol, seven patients with clinical suspicion of CECS and eight healthy volunteers underwent DTI of the calf muscle in a Siemens MAGNETOM Verio 3 T scanner at rest and after treadmill exertion at four different T(d) values. Radial diffusion values λ(rad) were computed for each of seven different muscle compartments and analyzed with RPBM to produce estimates of free diffusivity D(0), fiber diameter a, and permeability κ. Fiber diameter estimates were compared with measurements from literature autopsy reference for several compartments. Response factors (post/pre-exercise ratios) were computed and compared between normal controls and CECS patients using a mixed-model two-way analysis of variance. All subjects and muscle compartments showed nearly time-independent diffusion along and strongly time-dependent diffusion transverse to the muscle fibers. RPBM estimates of fiber diameter correlated well with corresponding autopsy reference. D(0) showed significant (p < 0.05) increases with exercise for volunteers, and a increased significantly (p < 0.05) in volunteers. At the group level, response factors of all three parameters showed trends differentiating controls from CECS patients, with patients showing smaller diameter changes (p = 0.07), and larger permeability increases (p = 0.07) than controls. Time-dependent diffusion measurements combined with appropriate tissue modeling can provide enhanced microstructural specificity for in vivo tissue characterization. In CECS patients, our results suggest that high-pressure interfiber edema elevates free diffusion and restricts exercise-induced fiber dilation. Such specificity may be useful in differentiating CECS from other disorders or in predicting its response to either physical therapy or fasciotomy.
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Affiliation(s)
- Eric E. Sigmund
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
| | - Dmitry S. Novikov
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
| | - Dabang Sui
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
- Shanghai Tongyue Leasing Co., Ltd., Shanghai City, China
| | - Obehi Ukpebor
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
- Brooklyn College of the City of New York, New York, NY USA
| | - Steven Baete
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
| | - James S. Babb
- Division of Biostatistics, New York University Langone Medical Center, New York, NY USA
| | - Kecheng Liu
- Department of Neurology, Epilepsy Center, New York University Langone Medical Center, New York, NY USA
| | | | - Jane Kwon
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
- Department of Neurology, Epilepsy Center, New York University Langone Medical Center, New York, NY USA
| | - KellyAnne Mcgorty
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
- New York Presbyterian Hospital-Columbia University Medical Center, New York NY USA
| | - Jenny Bencardino
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
| | - Els Fieremans
- Department of Radiology, New York University Langone Medical Center, New York, NY USA
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12
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Mitchell J, Gladden LF, Chandrasekera TC, Fordham EJ. Low-field permanent magnets for industrial process and quality control. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 76:1-60. [PMID: 24360243 DOI: 10.1016/j.pnmrs.2013.09.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 05/13/2023]
Abstract
In this review we focus on the technology associated with low-field NMR. We present the current state-of-the-art in low-field NMR hardware and experiments, considering general magnet designs, rf performance, data processing and interpretation. We provide guidance on obtaining the optimum results from these instruments, along with an introduction for those new to low-field NMR. The applications of lowfield NMR are now many and diverse. Furthermore, niche applications have spawned unique magnet designs to accommodate the extremes of operating environment or sample geometry. Trying to capture all the applications, methods, and hardware encompassed by low-field NMR would be a daunting task and likely of little interest to researchers or industrialists working in specific subject areas. Instead we discuss only a few applications to highlight uses of the hardware and experiments in an industrial environment. For details on more particular methods and applications, we provide citations to specialized review articles.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom; Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
| | - L F Gladden
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom.
| | - T C Chandrasekera
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - E J Fordham
- Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
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13
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Quantification of porous microstructures in partially frozen drops using magnetic resonance techniques. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.08.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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14
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Asakawa N, Obata T. A utilization of internal/external quasi-static magnetic field gradients: transport phenomenon and magnetic resonance imaging of solid polymers. Polym J 2012. [DOI: 10.1038/pj.2012.101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Laun FB, Kuder TA, Wetscherek A, Stieltjes B, Semmler W. NMR-based diffusion pore imaging. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:021906. [PMID: 23005784 DOI: 10.1103/physreve.86.021906] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 05/23/2012] [Indexed: 06/01/2023]
Abstract
Nuclear magnetic resonance (NMR) diffusion experiments offer a unique opportunity to study boundaries restricting the diffusion process. In a recent Letter [Phys. Rev. Lett. 107, 048102 (2011)], we introduced the idea and concept that such diffusion experiments can be interpreted as NMR imaging experiments. Consequently, images of closed pores, in which the spins diffuse, can be acquired. In the work presented here, an in-depth description of the diffusion pore imaging technique is provided. Image artifacts due to gradient profiles of finite duration, field inhomogeneities, and surface relaxation are considered. Gradients of finite duration lead to image blurring and edge enhancement artifacts. Field inhomogeneities have benign effects on diffusion pore images, and surface relaxation can lead to a shrinkage and shift of the pore image. The relation between boundary structure and the imaginary part of the diffusion weighted signal is analyzed, and it is shown that information on pore coherence can be obtained without the need to measure the phase of the diffusion weighted signal. Moreover, it is shown that quite arbitrary gradient profiles can be used for diffusion pore imaging. The matrices required for numerical calculations are stated and provided as supplemental material.
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Affiliation(s)
- Frederik Bernd Laun
- Medical Physics in Radiology, German Cancer Research Center, DKFZ, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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16
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Simpson AJ, McNally DJ, Simpson MJ. NMR spectroscopy in environmental research: from molecular interactions to global processes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 58:97-175. [PMID: 21397118 DOI: 10.1016/j.pnmrs.2010.09.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Affiliation(s)
- André J Simpson
- Environmental NMR Center, Department of Chemistry, University of Toronto, Ontario, Canada.
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17
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Sughir A, Skiba M, Lameiras P, Coadou G, Lahiani-Skiba M, Oulyadi H. Study of interaction between tiagabine HCl and 2-HPβCD: investigation of inclusion process. J INCL PHENOM MACRO 2010. [DOI: 10.1007/s10847-009-9732-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Li L, Chen Q, Marble AE, Romero-Zerón L, Newling B, Balcom BJ. Flow imaging of fluids in porous media by magnetization prepared centric-scan SPRITE. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:1-8. [PMID: 19121591 DOI: 10.1016/j.jmr.2008.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 10/23/2008] [Accepted: 10/24/2008] [Indexed: 05/27/2023]
Abstract
MRI has considerable potential as a non-destructive probe of porous media, permitting rapid quantification of local fluid content and the possibility of local flow visualization and quantification. In this work we explore a general approach to flow velocity measurement in porous media by combining Cotts pulsed field gradient flow encoding with SPRITE MRI. This technique permits facile and accurate flow and dispersion coefficient mapping of fluids in porous media. This new approach has proven to be robust in characterizing fluid behavior. This method is illustrated through measurements of flow in pipes, flow in sand packs and flow in porous reservoir rocks. Spatially resolved flow maps and local fluid velocity distribution were acquired.
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Affiliation(s)
- Linqing Li
- MRI Centre, Department of Physics, P.O. Box 4400, University of New Brunswick, Fredericton, NB, Canada E3B 5A3
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19
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Mitchell J, Graf von der Schulenburg DA, Holland DJ, Fordham EJ, Johns ML, Gladden LF. Determining NMR flow propagator moments in porous rocks without the influence of relaxation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 193:218-225. [PMID: 18514556 DOI: 10.1016/j.jmr.2008.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 04/29/2008] [Accepted: 05/02/2008] [Indexed: 05/26/2023]
Abstract
Flow propagators, used for the study of advective motion of brine solution in porous carbonate and sandstone rocks, have been obtained without the influence of Nuclear Magnetic Resonance (NMR) relaxation times, T1 and T2. These spin relaxation mechanisms normally result in a loss of signal that varies depending on the displacement zeta of the flowing spins, thereby preventing the acquisition of quantitative propagator data. The full relaxation behaviour of the system under flow needs to be characterised to enable the implementation of a true quantitative measurement. Two-dimensional NMR correlations of zeta-T2 and T1-T2 are used in combination to provide the flow propagators without relaxation weighting. T1-zeta correlations cannot be used due to the loss of T1 information during the displacement observation time Delta. Here the moments of the propagators are extracted by statistical analysis of the full propagator shape. The measured displacements (first moments) are seen to correlate with the expected mean displacements for long observation times Delta. The higher order moments of the propagators determined by this method indicate those obtained previously using a correction were overestimated.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK
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20
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Griffith JD, Bayly AE, Johns ML. Evolving micro-structures in drying detergent pastes quantified using NMR. J Colloid Interface Sci 2007; 315:223-9. [PMID: 17669413 DOI: 10.1016/j.jcis.2007.06.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 06/14/2007] [Accepted: 06/19/2007] [Indexed: 11/28/2022]
Abstract
Magnetic resonance methods have been used to probe the evolution of the internal micro-structure of an industrially important detergent mixture, as a function of total water content. Measurements of the apparent diffusion coefficient of the water content were obtained as a function of diffusion observation time. These data were interpreted to render the surface-to-volume ratio and tortuosity of the pore space in which the water resided. Pore dimensions were found to decrease as moisture content was reduced, partially as a consequence of solute deposition. Deposition of solute material was confirmed through the application of NMR T(1) relaxation measurements. These were analysed using regularisation techniques to yield T(1) population distributions. Average pore sizes as a function of water content were extracted from this data and were in good agreement with the results of the diffusion analysis.
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Affiliation(s)
- J D Griffith
- Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge, UK
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21
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Mutina AR, Skirda VD. Porous media characterization by PFG and IMFG NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:122-8. [PMID: 17643327 DOI: 10.1016/j.jmr.2007.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 05/08/2007] [Accepted: 05/08/2007] [Indexed: 05/16/2023]
Abstract
Fully and partially filled with tridecane quartz sand was studied by different NMR techniques. The set of NMR experiments was carried out to obtain information about porous media geometry and fluid localization in it in case of partially filled porous space. The study was done using three NMR approaches: pulse field gradient NMR (PFG NMR), DDif experiment and tau-scanning experiment. The possibility to use all three approaches to study porous media properties even at the high resonance frequency is shown together with complementarity of the given by them information. Thus, first two approaches give information about porous sizes and geometry, at the same time tau-scanning experiment allows us to obtain information about distribution of internal magnetic field gradients in the porous space and draw conclusions about fluid localization in it.
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Affiliation(s)
- Albina R Mutina
- Department of Molecular Physics, Kazan State University, Kremlevskaya Street 18, 420008 Kazan, Russia.
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22
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Davies CJ, Griffith JD, Sederman AJ, Gladden LF, Johns ML. Rapid surface-to-volume ratio and tortuosity measurement using Difftrain. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 187:170-5. [PMID: 17485231 DOI: 10.1016/j.jmr.2007.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 04/10/2007] [Accepted: 04/12/2007] [Indexed: 05/15/2023]
Abstract
Analysis of diffusion measurements as a function of observation time (Delta), to calculate surface-to-volume ratios (S/V) and tortuosities (kappa), is a useful tool in the characterisation of porous media using NMR. However, using conventional pulsed field gradient (PFG) measurements, this requires long total experiment times (typically hours). Here, we show how the rapid diffusion measurement pulse sequence, Difftrain, can be used to provide the required experimental data much more rapidly (typically within minutes) with a consequential reduction in total experiment time of typically over an order of magnitude. Several novel modifications to the Difftrain pulse sequence are also presented to tailor it to this particular application; these include a variable delay between echoes (to ensure optimal echo position with respect to Delta) and a variable tip angle for the refocusing pulse (to ensure optimal use of available signal). Difftrain is applied to measure both S/V and kappa for a model glass bead pack; excellent agreement is found with both a conventional PFG measurement and with a bulk gravimetric measurement of S/V.
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Affiliation(s)
- Colin J Davies
- Magnetic Resonance Research Centre, Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge, UK
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Dertinger T, Pacheco V, von der Hocht I, Hartmann R, Gregor I, Enderlein J. Two-Focus Fluorescence Correlation Spectroscopy: A New Tool for Accurate and Absolute Diffusion Measurements. Chemphyschem 2007; 8:433-43. [PMID: 17269116 DOI: 10.1002/cphc.200600638] [Citation(s) in RCA: 262] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We present a new method to measure absolute diffusion coefficients at nanomolar concentrations with high precision. Based on a modified fluorescence correlation spectroscopy (FCS)-setup, this method is improved by introducing an external ruler for measuring the diffusion time by generating two laterally shifted and overlapping laser foci at a fixed and known distance. Data fitting is facilitated by a new two-parameter model to describe the molecule detection function (MDF). We present a recorded MDF and show the excellent agreement with the fitting model. We measure the diffusion coefficient of the red fluorescent dye Atto655 under various conditions and compare these values with a value achieved by gradient pulsed field NMR (GPF NMR). From these measurements we conclude, that the new measurement scheme is robust against optical and photophysical artefacts which are inherent to standard FCS. With two-focus-FCS, the diffusion coefficient of 4.26 x 10(-6) cm2s(-1) for Atto655 in water at 25 degrees C compares well with the GPF NMR value of 4.28 x 10(-6) cm2s(-1).
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Affiliation(s)
- Thomas Dertinger
- Institut für Biologische Informationsverarbeitung 1, Forschungszentrum Jülich, 52425 Jülich, Germany
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Singer PM, Leu G, Fordham EJ, Sen PN. Low magnetic fields for flow propagators in permeable rocks. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 183:167-77. [PMID: 16962343 DOI: 10.1016/j.jmr.2006.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 08/16/2006] [Accepted: 08/17/2006] [Indexed: 05/11/2023]
Abstract
Pulsed field gradient NMR flow propagators for water flow in Bentheimer sandstone are measured at low fields (1H resonance 2 MHz), using both unipolar and bipolar variants of the pulsed gradient method. We compare with propagators measured at high fields (1H resonance 85 MHz). We show that (i) measured flow propagators appear to be equivalent, in this rock, and (ii) the lower signal to noise ratio at low fields is not a serious limitation. By comparing different pulse sequences, we study the effects of the internal gradients on the propagator measurement at 2 MHz, which for certain rocks may persist even at low fields.
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Affiliation(s)
- Philip M Singer
- Schlumberger-Doll Research, 36 Old Quarry Road, Ridgefield, CT 06877, USA.
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Cavadini S, Dittmer J, Antonijevic S, Bodenhausen G. Slow Diffusion by Singlet State NMR Spectroscopy. J Am Chem Soc 2005; 127:15744-8. [PMID: 16277516 DOI: 10.1021/ja052897b] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Small diffusion coefficients can be measured by using populations of singlet states that have a relaxation time constant, T(s), which can be much longer than the longitudinal relaxation time, T1. Spatial information can be encoded with pulsed field gradients in the manner of stimulated echo sequences. Singlet states can be excited via double-quantum coherences to enhance the efficiency of phase encoding and decoding.
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Affiliation(s)
- Simone Cavadini
- Contribution from the Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, BCH, 1015 Lausanne, Switzerland
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26
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Asakawa N, Matsubara K, Inoue Y. Low-dimensional lattice diffusion in solids investigated by nuclear spin echo measurements. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.02.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Leu G, Fordham EJ, Hürlimann MD, Frulla P. Fixed and pulsed gradient diffusion methods in low-field core analysis. Magn Reson Imaging 2005; 23:305-9. [PMID: 15833632 DOI: 10.1016/j.mri.2004.11.065] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Accepted: 11/12/2004] [Indexed: 11/17/2022]
Abstract
We review diffusion-weighted relaxation protocols for two-dimensional diffusion/relaxation time (D, T(2)) distributions and their application to fluid-saturated sedimentary rocks at low fields typical of oil-well logging tools (< or = 2 MHz for 1H). Fixed field gradient (FFG) protocols may be implemented in logging tools and in the laboratory; there, pulsed field gradient (PFG) protocols are also available. In either category, direct or stimulated echoes may be used for the diffusion evolution periods. We compare the results of several variant FFG and PFG protocols obtained on liquids and two contrasting sedimentary rocks. For liquids and rocks of negligible internal gradients (g(int)), results are comparable, as expected, for all the studied protocols. For rocks of strong g(int), protocol-dependent artifacts are seen in the joint (D, T2) distributions, consistent with the effects of the internal fields. For laboratory petrophysics, the PFG methods offer several advantages: (a) significantly improved signal-to-noise ratio and acquisition times for repetitions over many samples; (b) freedom from heteronuclear contamination when fluorinated liquids are used in core holders; and (c) a palette of variants--one comparable with the FFG--for the study of rocks of significant g(int). Given suitable hardware, both PFG and FFG methods can be implemented in the same bench-top apparatus, providing a versatile test bed for application in a petrophysical laboratory.
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Affiliation(s)
- Gabriela Leu
- Schlumberger-Doll Research, Ridgefield, CT 06877, USA
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Uh J, Watson AT. Nuclear Magnetic Resonance Determination of Surface Relaxivity in Permeable Media. Ind Eng Chem Res 2004. [DOI: 10.1021/ie030599m] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jinsoo Uh
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, and Department of Chemical Engineering, Colorado State University, Fort Collins, Colorado 80523-1370
| | - A. Ted Watson
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, and Department of Chemical Engineering, Colorado State University, Fort Collins, Colorado 80523-1370
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Petković J, Huinink HP, Pel L, Kopinga K. Diffusion in porous building materials with high internal magnetic field gradients. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 167:97-106. [PMID: 14987603 DOI: 10.1016/j.jmr.2003.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2003] [Revised: 11/04/2003] [Indexed: 05/24/2023]
Abstract
Measuring the water diffusivity in porous building materials with NMR is hindered by the presence of large internal magnetic field gradients originating from magnetic impurities (Fe). To investigate the diffusion of water in these materials, a stimulated echo NMR technique is applied. A new analytical equation for the long-time signal decay in the presence of spatially varying internal field gradients is derived. This equation is experimentally confirmed by measurements on representative materials with large internal gradients (fired-clay brick and sintered crushed glass) and a material with very small internal gradients (glass filter). The diffusivity is determined in the long time limit, where it is constant and limited by the tortuosity of the pore structure. Tortuosities of different samples derived from the NMR data show an excellent agreement with the macroscopic tortuosities measured by electrochemical impedance spectroscopy. The developed technique can also be applied in unsaturated media, during e.g., drying, water absorption, and concentration changes. The characteristic length scales of the internal field fluctuations estimated from the model are compared with the structural length scales, whereas the magnitude of these fluctuations is compared with results of macroscopic magnetization measurements.
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Affiliation(s)
- J Petković
- Department of Applied Physics, Eindhoven University of Technology, P.O.Box 513, 5600 MB Eindhoven, The Netherlands
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Minard KR, Holtom GR, Kathmann LE, Majors PD, Thrall BD, Wind RA. Simultaneous1H PFG-NMR and confocal microscopy of monolayer cell cultures: Effects of apoptosis and necrosis on water diffusion and compartmentalization. Magn Reson Med 2004; 52:495-505. [PMID: 15334567 DOI: 10.1002/mrm.20179] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We induced apoptosis and necrosis in monolayer cultures of Chinese hamster ovary cells using okadaic acid and hydrogen peroxide (H2O2), respectively, and examined the effect on water diffusion and compartmentalization using pulsed-field-gradient (PFG) 1H-NMR and simultaneous confocal microscopy. In PFG experiments characterized by a fixed diffusion time (<4.7 ms) and variable b-values (0-27000 s/mm2), 1H-NMR data collected with untreated cells exhibited multiexponential behavior. Analysis with a slow-exchange model revealed two distinct cellular water compartments with different apparent diffusion coefficients (ADCs; 0.56, 0.06 x 10(-3) mm2/s) and volume fractions (0.96 and 0.04). During the first 12 hr of necrosis or apoptosis, the amount of water in the smallest compartment increased twofold before significant changes in cell density or plasma membrane integrity occurred. Over the same period, water content in the largest compartment decreased by a factor of >2 in apoptotic cells, in accordance with observed cell shrinkage, and changed little in necrotic counterparts, where only slight swelling was evident. These results indicate that PFG 1H-NMR serves as a sensitive indicator of early cell death in monolayer cultures, and can be used to distinguish apoptosis from necrosis. Measurements of restricted diffusion and water exchange are presented to elucidate the compartment origins and justify the model assumptions.
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Affiliation(s)
- Kevin R Minard
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
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Valiullin R, Furó I, Skirda V, Kortunov P. NMR magnetization transfer as a tool for characterization of nanoporous materials. Magn Reson Imaging 2003; 21:299-303. [PMID: 12850722 DOI: 10.1016/s0730-725x(03)00158-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The application of nuclear magnetic resonance magnetization transfer experiments to probe the surface-to-volume ratio and pore morphology of porous materials with characteristic pore sizes of 1-100 nm is described. The method is based on the phenomenon of incomplete freezing of liquids in small pores where a few monolayers adjacent to the pore walls remain liquid. Sufficient difference between the transverse relaxation times in the solid frozen core and liquid surface layer allows the initial preparation and subsequent re-equilibration of a solid-liquid magnetization grating. The method is demonstrated using model nanoporous materials with known characteristics. The ensuing problems of the mechanism of the magnetization transfer through the interface and within the frozen core are discussed and elucidated by pulsed-field-gradient NMR experiments.
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Affiliation(s)
- R Valiullin
- Department of Molecular Physics, Kazan State University, 420008 Kazan, Russia.
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Ferrage F, Zoonens M, Warschawski DE, Popot JL, Bodenhausen G. Slow diffusion of macromolecular assemblies by a new pulsed field gradient NMR method. J Am Chem Soc 2003; 125:2541-5. [PMID: 12603142 DOI: 10.1021/ja0211407] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The translational diffusion coefficient of an integral membrane protein/surfactant complex has been measured using a novel pulsed field gradient NMR method. In this new approach, the information about the localization of the molecules is temporarily stored in the form of longitudinal magnetization of isotopes with long spin-lattice relaxation times. This allows one to increase the duration of the diffusion interval by about 1 order of magnitude. Unlike standard proton NMR methods using pulsed field gradients and stimulated echoes, the new method can be applied to macromolecular assemblies with diffusion coefficients well below 10(-10) m(2) s(-1), corresponding to masses in excess of 25 kDa in aqueous solution at room temperature. The method was illustrated by application to a water-soluble complex of tOmpA, the hydrophobic transmembrane domain of bacterial outer membrane protein A, with the detergent octyl-tetraoxyethylene (C(8)E(4); overall mass of complex approximately 45 kDa). The diffusion coefficient was found to be D = (4.99 +/- 0.07) x 10(-11) m(2) s(-1), consistent with measurements by size exclusion chromatography and by ultracentrifugation. The method has also been applied to a solution of recombinant human tRNA(3)(Lys), which has a molecular mass of 24 kDa, and the diffusion coefficient D = (1.05 +/- 0.015) x 10(-10) m(2) s(-1).
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Affiliation(s)
- Fabien Ferrage
- Département de Chimie, associé au CNRS, Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05, France
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Reese TG, Heid O, Weisskoff RM, Wedeen VJ. Reduction of eddy-current-induced distortion in diffusion MRI using a twice-refocused spin echo. Magn Reson Med 2003; 49:177-82. [PMID: 12509835 DOI: 10.1002/mrm.10308] [Citation(s) in RCA: 991] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Image distortion due to field gradient eddy currents can create image artifacts in diffusion-weighted MR images. These images, acquired by measuring the attenuation of NMR signal due to directionally dependent diffusion, have recently been shown to be useful in the diagnosis and assessment of acute stroke and in mapping of tissue structure. This work presents an improvement on the spin-echo (SE) diffusion sequence that displays less distortion and consequently improves image quality. Adding a second refocusing pulse provides better image quality with less distortion at no cost in scanning efficiency or effectiveness, and allows more flexible diffusion gradient timing. By adjusting the timing of the diffusion gradients, eddy currents with a single exponential decay constant can be nulled, and eddy currents with similar decay constants can be greatly reduced. This new sequence is demonstrated in phantom measurements and in diffusion anisotropy images of normal human brain.
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Affiliation(s)
- T G Reese
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA.
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Stapf S, Damion RA, Packer KJ. Time Correlations in Fluid Transport Obtained by Sequential Rephasing Gradient Pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 137:316-323. [PMID: 10089165 DOI: 10.1006/jmre.1998.1685] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present a basic experiment by which the evolution of the displacement probability density (propagator) of static or flowing fluid in N successive time intervals is obtained by single labeling, coupled with multiple rephasing events during the course of a pulsed field-gradient sequence. We term this type of sequence SERPENT: SEquential Rephasing by Pulsed field-gradients Encoding N Time-intervals. Realizations of the SERPENT experiment for the case N = 2 which include spin echo, stimulated echo, and Carr-Purcell pulse sequences are suggested. They have in common a spatial spin-labeling of the initial magnetization by a gradient of area q0, followed by successive rephasing via gradients q1 and q2 at times t = Delta1 and t = Delta2, respectively, where q0 + q1 + q2 = 0. A two-dimensional Fourier transform with respect to q1 and q2 gives directly the joint probability density W2(R1, Delta1; R2, Delta2) for displacements R1 and R2 in times Delta1 and Delta2, respectively. q1 and q2 may be in arbitrary directions. Assuming R1 ||R2, the correlation coefficient rhoR1,R2 then reflects the time-history of the fluctuating velocities. The behavior of the cross moment <R1(Delta1). R2(Delta2)> can be obtained from either a full two-dimensional or a set of one-dimensional SERPENT measurements. Experimental results are presented for water flowing through a bed of packed glass beads. While Delta1 is appropriately chosen to sample the short-time velocity field within the system, increasing Delta2 clearly shows the loss of correlation when the average fluid element displacement exceeds the bead diameter. Copyright 1999 Academic Press.
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Affiliation(s)
- S Stapf
- Department of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
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Jerschow A, Muller N. Efficient simulation of coherence transfer pathway selection by phase cycling and pulsed field gradients in NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 134:17-29. [PMID: 9740726 DOI: 10.1006/jmre.1998.1491] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The selection of well-defined coherence transfer pathways is an essential feature of all but the simplest NMR and EPR pulse sequences. This selection can be achieved by phase cycling and by pulsed field gradients. The properties of the RF-pulses (flip angle, offset effects, inhomogeneity) and transport phenomena (diffusion, flow) in conjunction with gradients cause a weighting of the different coherence transfer pathways. We present a method by which the selection process can be simulated efficiently and visualized easily. In its basic form it involves straightforward matrix manipulations without reference to the density matrix and the particular spin system. This method is implemented in a MATLAB program, called CCCP (Complete Calculation of Coherence Pathways). Copyright 1998 Academic Press.
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Affiliation(s)
- A Jerschow
- Section de Chimie, BCH, CH-1015, Lausanne-Dorigny, Switzerland
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40
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Jerschow A, Müller N. Diffusion-Separated Nuclear Magnetic Resonance Spectroscopy of Polymer Mixtures. Macromolecules 1998. [DOI: 10.1021/ma9801772] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexej Jerschow
- Institut für Chemie, Johannes Kepler University Linz, Altenbergerstrasse 69, A-4040 Linz, Austria, and MR-Center, SINTEF UNIMED, N-7034 Trondheim, Norway
| | - Norbert Müller
- Institut für Chemie, Johannes Kepler University Linz, Altenbergerstrasse 69, A-4040 Linz, Austria, and MR-Center, SINTEF UNIMED, N-7034 Trondheim, Norway
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Pfeuffer J, Flögel U, Dreher W, Leibfritz D. Restricted diffusion and exchange of intracellular water: theoretical modelling and diffusion time dependence of 1H NMR measurements on perfused glial cells. NMR IN BIOMEDICINE 1998; 11:19-31. [PMID: 9608585 DOI: 10.1002/(sici)1099-1492(199802)11:1<19::aid-nbm499>3.0.co;2-o] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Intracellular diffusion properties of water in F98 glioma cells immobilized in basement membrane gel threads, are investigated with a pulsed-field-gradient spin-echo NMR technique at diffusion times from 6 to 2000 ms and at different temperatures. In extended model calculations the concept of 'restricted intracellular diffusion at permeable boundaries' is described by a combined Tanner-Kärger formula. Signal components in a series of ct experiments (constant diffusion time) are separated due to different diffusion properties (Gaussian and restricted diffusion), and physiological as well as morphological cell parameters are extracted from the experimental data. The intracellular apparent diffusion coefficients strongly depend on the diffusion time and are up to two orders of magnitude smaller than the self diffusion constant of water. Propagation lengths are found to be in the range of 4-7 microns. Hereby intracellular signals of compartments with a characteristic diameter could be selected by an appropriate gradient strength. With cg experiments (constant gradient) a mean intracellular residence time for water is determined to be about 50 ms, and the intrinsic intracellular diffusion constant is estimated to 1 x 10(-3)mm2/s. Studying the water diffusion in glial cells provides basic understanding of the intracellular situation in brain tissue and may elucidate possible influences on the changes in the diffusion contrast during ischemic conditions.
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Affiliation(s)
- J Pfeuffer
- Fachbereich Biologie/Chemie, Universität Bremen, Germany
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Amin MHG, Gibbs SJ, Chorley RJ, Richards KS, Carpenter TA, Hall LD. Study of flow and hydrodynamic dispersion in a porous medium using pulsed–field–gradient magnetic resonance. Proc Math Phys Eng Sci 1997. [DOI: 10.1098/rspa.1997.0028] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- M. H. G. Amin
- Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK
| | - S. J. Gibbs
- Herchel Smith Laboratory for Medicinal Chemistry, University of Cambridge, School of Clinical Medicine, Robinson Way, Cambridge CB2 2PZ, UK
| | - R. J. Chorley
- Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK
| | - K. S. Richards
- Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK
| | - T. A. Carpenter
- Herchel Smith Laboratory for Medicinal Chemistry, University of Cambridge, School of Clinical Medicine, Robinson Way, Cambridge CB2 2PZ, UK
| | - L. D. Hall
- Herchel Smith Laboratory for Medicinal Chemistry, University of Cambridge, School of Clinical Medicine, Robinson Way, Cambridge CB2 2PZ, UK
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Waggoner RA, Fukushima E. Velocity distribution of slow fluid flows in Bentheimer sandstone: an NMRI and propagator study. Magn Reson Imaging 1996; 14:1085-91. [PMID: 9071000 DOI: 10.1016/s0730-725x(96)00110-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This work addresses the special problems of measuring flow velocity distributions in rock by NMR methods. Specifically, these problems are to measure very slow flows as well as flows in the presence of background magnetic field gradients caused by heterogeneities of the rock. We modify a stimulated echo sequence for use in diffusion measurements, in order to maximize velocity sensitivity and minimize background gradient effects. Accurate velocity images of Soltrol 220 oil in sandstone were made for flow velocities up to around 0.04 mm/s with an imager that does not have echo-planar capability. Accurate velocity distributions by the propagator method can be obtained even with stimulated echo delays of 1.9 T1 by phase cycling combined with suitable crusher gradients.
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Abstract
The NMR pulsed field gradient spin-echo (PFGSE) amplitude M(k,t) is a direct measure of the diffusion propagator of the molecules of a fluid diffusing in the pores of a porous medium. For small values of k = gamma g delta, where g is the gradient strength, delta is the duration of the gradient pulse, and gamma the gyromagnetic ratio, the PFGSE amplitude gives the diffusion coefficient D(t). The exact short-time diffusion coefficient, D(t)/D0 = 1-(4 square root of D0tS)/(9 Vp square root of pi)-D0tHS/(12Vp) + rho tS/6Vp, provides an important method for determining the surface to pore-volume ratio S/Vp. Here the mean surface curvature H = <1/R1 + 1/R2>. Combining early D(t) with the magnetization decay one obtains the surface relaxivity rho. The long-time effective diffusion constant derived from PFGSE gives information on the tortuosity of the connected space. The diffusion coefficient measured by PFGSE equals that derived from electrical conductivity only when rho = 0. Exact solutions with partially absorbing boundary conditions for a periodic structure are used to illustrate the influence of rho on the diffusion coefficient. M(k,t) can be well represented by a convolution of the structure factor of the connected pore space with an appropriate Gaussian propagator. This ansatz provides a model-independent way of obtaining the structure factor.
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Affiliation(s)
- P N Sen
- Schlumberger-Doll Research, Ridgefield, CT 06877-4108
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