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Simultaneous determination of multiple coupling networks by high-resolution 2D J-edited NMR spectroscopy. Anal Chim Acta 2021; 1185:339055. [PMID: 34711310 DOI: 10.1016/j.aca.2021.339055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 11/24/2022]
Abstract
J coupling constitutes an important NMR parameter for molecular-level composition analysis and conformation elucidation. Dozens of J-based approaches have been exploited for J coupling measurement and coupling network determination, however, they are generally imposed to insufficient spectral resolution to resolve crowded NMR resonances and low measurement efficiency that a single experiment records one J coupling network. Herein, we propose a general NMR method to collect high-resolution 2D J-edited NMR spectra, which are characterized with advantages of pure absorptive lineshapes, decoupled chemical shift dimension, as well as eliminated axial peaks, thus facilitating J coupling partner assignments and J coupling constant measurements. More meaningfully, this protocol allows simultaneous determination of multiple coupling networks for highly efficient multiplet analyses via addressing multiple protons within one single experiment. Additionally, another variant is proposed for high-resolution applications under adverse magnetic field conditions. Therefore, this study provides a useful NMR protocol for configurational and structural studies with extensive applications in chemistry, biology, and material science.
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Benders S, Jerschow A. 7Li intermolecular multiple-quantum coherences in liquids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 329:107010. [PMID: 34102585 DOI: 10.1016/j.jmr.2021.107010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
We report here evidence for the generation of 7Li multiple-quantum coherences in aqueous solutions outside of regimes where conventional multiple-quantum coherences due to alignment or quadrupolar relaxation could be observed. These coherences are shown to observe nonlinear behavior as a function of concentration, and hence these effects can be identified as arising from intermolecular multiple-quantum coherences. Due to the importance of lithium ion solutions for the study of electrochemical systems, awareness of such coherences is particularly important in the interpretation of experimental results, and new applications using lithium as a probe may become possible on this basis.
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Affiliation(s)
- Stefan Benders
- Department of Chemistry, New York University, New York, NY 10003, United States
| | - Alexej Jerschow
- Department of Chemistry, New York University, New York, NY 10003, United States.
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Zhan H, Huang Y, Chen Z. High-Resolution Probing of Heterogeneous Samples by Spatially Selective Pure Shift NMR Spectroscopy. J Phys Chem Lett 2019; 10:7356-7361. [PMID: 31718190 DOI: 10.1021/acs.jpclett.9b03092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Liquid NMR spectroscopy generally encounters two major challenges for high-resolution measurements of heterogeneous samples, namely, magnetic field inhomogeneity caused by spatial variations in magnetic susceptibility and spectral congestion induced by crowded NMR resonances. In this study, we demonstrate a spatially selective pure shift NMR approach for high-resolution probing of heterogeneous samples by suppressing effects of field inhomogeneity and J coupling simultaneously. A Fourier phase encoding strategy is proposed and implemented for spatially selective pure shift experiments to enhance signal intensity and further boost the applicability. The spatially selective pure shift method can serve as an effective tool for high-resolution probing of heterogeneous samples, thus presenting interesting prospects for extensive applications in the fields of chemistry, physics, biology, and food science.
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Affiliation(s)
- Haolin Zhan
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces , Xiamen University , Xiamen 361005 , China
| | - Yuqing Huang
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces , Xiamen University , Xiamen 361005 , China
| | - Zhong Chen
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces , Xiamen University , Xiamen 361005 , China
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A Single-Scan Inhomogeneity-Tolerant NMR Method for High-Resolution Two-Dimensional J-Resolved Spectroscopy. IEEE Trans Biomed Eng 2018; 66:1559-1566. [PMID: 30334743 DOI: 10.1109/tbme.2018.2875797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE A robust and general single-scan NMR method, SGEN-J, is proposed for real-time recording high-resolution two-dimensional (2D) homonuclear J-resolved spectra under inhomogeneous magnetic fields. METHODS This proposed NMR method is designed based on the combination of a selective gradient encoding module to encode chemical shifts with spatial positions, and a J-modulation decoding module to reveal encoded structural information. Multi-band SGEN-J is further implemented to effectively enhance spectral sensitivity with a sustained tolerance of field inhomogeneity. RESULTS The SGEN-J provides an effective way to rapidly recover chemical shifts, J coupling constants, and multiplet patterns under inhomogeneous magnetic fields. Experiments on various chemical solutions were performed to demonstrate the feasibility and effectiveness of SGEN-J. Experiments on pig marrow tissues were performed to further investigate the applicability of SGEN-J to biological samples with intrinsic susceptibility variations. CONCLUSION Based on intrinsic advantages, SGEN-J serves as a helpful complement to existing 2D J-resolved methodologies in molecular structure elucidation and biomedical study, and offer bright perspectives for real-time analyzing in vivo biological systems and monitoring in situ chemical reactions.
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Lin Y, Guan Q, Su J, Chen Z. Combining Fourier phase encoding and broadband inversion toward J-edited spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:1-7. [PMID: 29609072 DOI: 10.1016/j.jmr.2018.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
Nuclear magnetic resonance (NMR) spectra are often utilized for gathering accurate information relevant to molecular structures and composition assignments. In this study, we develop a homonuclear encoding approach based on imparting a discrete phase modulation of the targeted cross peaks, and combine it with a pure shift experiments (PSYCHE) based J-modulated scheme, providing simple 2D J-edited spectra for accurate measurement of scalar coupling networks. Chemical shifts and J coupling constants of protons coupled to the specific protons are demonstrated along the F2 and F1 dimensions, respectively. Polychromatic pulses by Fourier phase encoding were performed to simultaneously detect several coupling networks. Proton-proton scalar couplings are chosen by a polychromatic pulse and a PSYCHE element. Axis peaks and unwanted couplings are complete eradicated by incorporating a selective COSY block as a preparation period. The theoretical principles and the signal processing procedure are laid out, and experimental observations are rationalized on the basis of theoretical analyses.
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Affiliation(s)
- Yulan Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China.
| | - Quanshuai Guan
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Jianwei Su
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of 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 of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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Huang Z, Guan Q, Chen Z, Frydman L, Lin Y. A discrete Fourier-encoded, diagonal-free experiment to simplify homonuclear 2D NMR correlations. J Chem Phys 2017; 147:034201. [PMID: 28734279 DOI: 10.1063/1.4990541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy has long served as an irreplaceable, versatile tool in physics, chemistry, biology, and materials sciences, owing to its ability to study molecular structure and dynamics in detail. In particular, the connectivity of chemical sites within molecules, and thereby molecular structure, becomes visible by multi-dimensional NMR. Homonuclear correlation experiments are a powerful tool for identifying coupled spins. Generally, diagonal peaks in these correlation spectra display the strongest intensities and do not offer any new information beyond the standard one-dimensional spectrum, whereas weaker, symmetrically placed cross peaks contain most of the coupling information. The cross peaks near the diagonal are often affected by the tails of strong diagonal peaks or even obscured entirely by the diagonal. In this paper, we demonstrate a homonuclear encoding approach based on imparting a discrete phase modulation of the targeted cross peaks and combine it with a site-selective sculpting scheme, capable of simplifying the patterns arising in these 2D correlation spectra. The theoretical principles of the new methods are laid out, and experimental observations are rationalized on the basis of theoretical analyses. The ensuing techniques provide a new way to retrieve 2D coupling information within homonuclear spin systems, with enhanced sensitivity, speed, and clarity.
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Affiliation(s)
- Zebin Huang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Quanshuai Guan
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of 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 of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
| | - Lucio Frydman
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Yulan Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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Ye Q, Chen L, Qiu W, Lin L, Sun H, Cai S, Wei Z, Chen Z. Accelerating two-dimensional nuclear magnetic resonance correlation spectroscopy via selective coherence transfer. J Chem Phys 2017; 146:014202. [PMID: 28063447 DOI: 10.1063/1.4973547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy serves as an important tool for both qualitative and quantitative analyses of various systems in chemistry, biology, and medicine. However, applications of one-dimensional 1H NMR are often restrained by the presence of severe overlap among different resonances. The advent of two-dimensional (2D) 1H NMR constitutes a promising alternative by extending the crowded resonances into a plane and thereby alleviating the spectral congestions. However, the enhanced ability in discriminating resonances is achieved at the cost of extended experimental duration due to necessity of various scans with progressive delays to construct the indirect dimension. Therefore, in this study, we propose a selective coherence transfer (SECOT) method to accelerate acquisitions of 2D correlation spectroscopy by converting chemical shifts into spatial positions within the effective sample length and then performing an echo planar spectroscopic imaging module to record the spatial and spectral information, which generates 2D correlation spectrum after 2D Fourier transformation. The feasibility and effectiveness of SECOT have been verified by a set of experiments under both homogeneous and inhomogeneous magnetic fields. Moreover, evaluations of SECOT for quantitative analyses are carried out on samples with a series of different concentrations. Based on these experimental results, the SECOT may open important perspectives for fast, accurate, and stable investigations of various chemical systems both qualitatively and quantitatively.
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Affiliation(s)
- Qimiao Ye
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Lin Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Wenqi Qiu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Liangjie Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Huijun Sun
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Zhiliang Wei
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
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8
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Zhang Z, Shemesh N, Frydman L. Efficient spectroscopic imaging by an optimized encoding of pretargeted resonances. Magn Reson Med 2017; 77:511-519. [PMID: 26910285 PMCID: PMC5184843 DOI: 10.1002/mrm.26161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/11/2016] [Accepted: 01/20/2016] [Indexed: 12/25/2022]
Abstract
PURPOSE A "relaxation-enhanced" (RE) approach to acquire in vivo localized spectra with flat baselines and good sensitivity has been recently proposed. As RE MR spectroscopy (MRS) targets a subset of a priori known resonances, new possibilities arise to acquire spectroscopic imaging data in faster, more efficient manners. This is hereby illustrated by Spectroscopically Encoded Chemical Shift Imaging (SECSI). METHODS SECSI delivers spectral/spatial correlations by collecting gradient echo trains whose timings are defined by the shifts of the resonances to be disentangled. Condition number considerations allow one to unravel these image contributions for various sites by a simple matrix inversion. The efficiency of the ensuing method is high enough to enable a sampling of additional spatial axes by means of their phase encoding in spin-echo trains. RESULTS The one-dimensional (1D) spectral / 2D spatial SECSI acquisitions were implemented on phantom, ex vivo, and in vivo models. In all cases, quality site-resolved images were obtained. The experimentally observed enhancements were consistent with theoretical signal-to-noise ratio derivations. CONCLUSION While still bound by MRSI's sensitivity limitations, a novel spectroscopic imaging protocol exploiting a priori information, selective excitations and multiple echo encodings, was proposed and demonstrated. The method is promising when dealing with high T2 / T2* ratios, sparse data, or hyperpolarization studies. Magn Reson Med 77:511-519, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zhiyong Zhang
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian 361005, China
| | - Noam Shemesh
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Lucio Frydman
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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Affiliation(s)
- G. A. Nagana Gowda
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine and
| | - Daniel Raftery
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine and
- Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, United States
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10
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Lin Y, Smith PES, Zhang Z, Frydman L. A fast approach to 3D HSQC-based spectroscopy based on a Fourier phase encoding of pre-targeted resonances. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:95-102. [PMID: 27894014 DOI: 10.1016/j.jmr.2016.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/14/2016] [Accepted: 11/19/2016] [Indexed: 06/06/2023]
Abstract
Multidimensional Nuclear Magnetic Resonance (NMR) provides a unique window into structure and dynamics at an atomic level. Traditionally, given the scan-by-scan time modulation involved in these experiments, the duration of nD NMR increases exponentially with spectral dimensionality. In addition, acquisition times increase as the number of spectral elements being sought in each indirect domain - given by the ratio between the spectral bandwidth being targeted and the resolution desired. These long sampling times can be substantially reduced by exploiting information that is often available from lower-dimensionality acquisitions. This work presents a novel approach that exploits previous 2D information to speed up the acquisition of 3D spectra, based on what we denote as a Time-Optimized FouriEr Encoding (TOFEE) of pre-targeted peaks. Such 3D TOFEE experiments, which present points in common with Hadamard-encoded 3D acquisitions, do not necessarily require more scans than their 2D counterparts. This is here demonstrated based on extensions of 2D Heteronuclear Single-quantum Coherence (HSQC) experiments, to 3D HSQC-TOCSY or 3D HSQC-NOESY acquisitions. The theoretical basis of this new approach is given, and experimental demonstrations are presented on small molecule and protein-based model systems.
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Affiliation(s)
- Yulan Lin
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel; Department of Electronic Science, Xiamen University, Xiamen 361005, China.
| | - Pieter E S Smith
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Zhiyong Zhang
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Lucio Frydman
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
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Ahmed-Omer B, Sliwinski E, Cerroti JP, Ley SV. Continuous Processing and Efficient in Situ Reaction Monitoring of a Hypervalent Iodine(III) Mediated Cyclopropanation Using Benchtop NMR Spectroscopy. Org Process Res Dev 2016. [DOI: 10.1021/acs.oprd.6b00177] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Batool Ahmed-Omer
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Eric Sliwinski
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - John P. Cerroti
- Magritek GmbH, Gebäude VO (Building VO), Triwo Technopark Aachen, Philipsstrasse 8, 52068 Aachen, Germany
| | - Steven V. Ley
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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12
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Lin Y, Lupulescu A, Frydman L. Multidimensional J-driven NMR correlations by single-scan offset-encoded recoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 265:33-44. [PMID: 26852416 DOI: 10.1016/j.jmr.2015.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
Two-dimensional (2D) correlations between bonded heteroatoms, lie at the cornerstone of many uses given to contemporary nuclear magnetic resonance (NMR). Improving the efficiency with which these correlations are established is an important topic in modern NMR, with potential applications in rapid chemical analysis and dynamic biophysical studies. Alternatives have been developed over the last decade to speed up these experiments, based among others on reducing the number of data points that need to be sampled, and/or shortening the inter-scan delays. Approaches have also been proposed to forfeit multi-scan schemes altogether, and complete full 2D correlations in a single shot. Here we explore and discuss a new alternative enabling the collection of such very fast - in principle, single-scan - acquisitions of 2D heteronuclear correlations among bonded species, which operates on the basis of a partial reintroduction of J couplings. Similar approaches had been proposed in the past based on collecting coupled spectra for arrays of off-resonance decoupling values; the proposal that is here introduced operates on the basis of suitably incorporating frequency-swept pulses, into spin-echo sequences. Thanks to the offset-dependent amplitude modulations of the in- and anti-phase components that such sequences impart, chemical shifts of coupled but otherwise unobserved nuclear species, can be extracted from the relative intensities and phases of J-coupled multiplets observed in one-dimensional acquisitions. A description of the steps needed to implement this rapid acquisition approach in a quantitative fashion, as well as applications of the ensuing sequences, are presented.
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Affiliation(s)
- Yulan Lin
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel; Department of Electronic Science, Xiamen University, Xiamen 361005, China
| | - Adonis Lupulescu
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lucio Frydman
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
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13
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Herrera A, Fernández-Valle E, Martínez-Álvarez R, Molero-Vílchez D, Pardo-Botero ZD, Sáez-Barajas E. Monitoring organic reactions by UF-NMR spectroscopy. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:952-970. [PMID: 25998506 DOI: 10.1002/mrc.4240] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 02/26/2015] [Accepted: 03/03/2015] [Indexed: 06/04/2023]
Abstract
Standard 2D NMR experiments suffer from the many t1 increments needed for spectra with sufficient digital resolution in the indirect dimension. Despite the different methodological approaches to overcome this problem, these increments have prevented studies of fast reactions. The development of ultrafast NMR (UF-NMR) has decisively speeded up the time scale of standard NMR to allow the study of organic reactions as they happen in real time to reveal mechanistic details. This mini-review summarizes the results achieved in monitoring organic reactions through this exciting technique.
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Affiliation(s)
- Antonio Herrera
- CAI-RMN, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Química Orgánica I, Facultad de Químicas, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Roberto Martínez-Álvarez
- Departamento de Química Orgánica I, Facultad de Químicas, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Zulay D Pardo-Botero
- CAI-RMN, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Química Orgánica I, Facultad de Químicas, Universidad Complutense de Madrid, Madrid, Spain
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Zhang Z, Frydman L. MRSI via fully-refocused spatiotemporal encoding with polychromatic spectral pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:24-31. [PMID: 26282060 PMCID: PMC5035683 DOI: 10.1016/j.jmr.2015.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/14/2015] [Accepted: 07/29/2015] [Indexed: 05/27/2023]
Abstract
A novel method for the rapid acquisition of quality multi-slice 2D images targeting a small number of spectroscopic resonances, is introduced and illustrated. The method exploits the robustness derived from recently proposed spatiotemporal encoding (SPEN) methods, when operating in the so-called "fully refocused" mode. Fully-refocused SPEN provides high-fidelity single-shot images thanks to its refocusing of all offset-derived effects throughout the course of the acquisition. This refocusing, however, prevents exploiting such robustness for spectroscopic imaging. We propose here a solution to this limitation, based on the use of polychromatic refocusing pulses. It is shown that if used to address a series of a priori known resonance positions, these pulses can lead to quality spectroscopic images in a small number of scans - generally equal or slightly larger than the number of targeted peaks. Such strategy is explored in combination with both fully-refocused SPEN and echo-planar-imaging (EPI) acquisitions. The expected SPEN advantages were observed in both phantom-based models, and in in vivo results of fat and water separation in mice at 7 T.
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Affiliation(s)
- Zhiyong Zhang
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel; Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian 361005, China
| | - Lucio Frydman
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
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15
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O'Brien KA, Griffin JL, Murray AJ, Edwards LM. Mitochondrial responses to extreme environments: insights from metabolomics. EXTREME PHYSIOLOGY & MEDICINE 2015; 4:7. [PMID: 25949809 PMCID: PMC4422479 DOI: 10.1186/s13728-015-0026-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/07/2015] [Indexed: 12/12/2022]
Abstract
Humans are capable of survival in a remarkable range of environments, including the extremes of temperature and altitude as well as zero gravity. Investigation into physiological function in response to such environmental stresses may help further our understanding of human (patho-) physiology both at a systems level and in certain disease states, making it a highly relevant field of study. This review focuses on the application of metabolomics in assessing acclimatisation to these states, particularly the insights this approach can provide into mitochondrial function. It includes an overview of metabolomics and the associated analytical tools and also suggests future avenues of research.
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Affiliation(s)
- Katie A O'Brien
- Centre of Human & Aerospace Physiological Sciences, King's College London, London, UK
| | - Julian L Griffin
- MRC Human Nutrition Research Unit, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, England ; Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK
| | - Lindsay M Edwards
- Centre of Human & Aerospace Physiological Sciences, King's College London, London, UK ; Fibrosis Drug Performance Unit, GlaxoSmithKline Medicines Research Centre, Stevenage, UK
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