Pub Date : 2025-04-01Epub Date: 2025-02-21DOI: 10.1016/j.jmr.2025.107860
Tamar Wolf, Lucio Frydman
Solid-state nuclear magnetic resonance (NMR) can shed light on atomic-level arrangements for most elements in the Periodic Table. This ability hinges on the possibility to overcome NMR's low sensitivity, particularly when dealing with unreceptive nuclei yielding ultra-wideline (>500 kHz) patterns from powdered samples. Herein, we present an experiment capable of enhancing the signals of such static samples, by transferring dipolar order from surrounding, highly polarized protons. The experiment, which we dub Dipolar-Order-based BRoadband Adiabatic INversion Cross-Polarization (DOBRAIN-CP), utilizes a Freeman-Kupče broadband inversion WURST pulse to perform CP over the wideline spectrum of the low receptivity species, while matching the low frequencies associated to 1H1H dipolar fields. We present analytical and numerical analyses of the spin-dynamics of DOBRAIN-CP for spin-½ nuclei, as well as for quadrupolar spins. Experimental results are also presented for spin-½, integer and half-integer quadrupolar spins; these show that although DOBRAIN-CP delivers broadband excitation and sensitivity enhancement compared to direct excitations, it does not exceed the sensitivity enhancement of the BRAIN-CP variant based on Hartmann-Hahn matching. The power requirements for DOBRAIN-CP are extremely low, yet long dipolar-order lifetimes T1D are needed to support the DOBRAIN-CP build-up times.
{"title":"Dipolar-order-based broadband adiabatic inversion as cross- polarization alternative in solid state Wideline NMR","authors":"Tamar Wolf, Lucio Frydman","doi":"10.1016/j.jmr.2025.107860","DOIUrl":"10.1016/j.jmr.2025.107860","url":null,"abstract":"<div><div>Solid-state nuclear magnetic resonance (NMR) can shed light on atomic-level arrangements for most elements in the Periodic Table. This ability hinges on the possibility to overcome NMR's low sensitivity, particularly when dealing with unreceptive nuclei yielding ultra-wideline (>500 kHz) patterns from powdered samples. Herein, we present an experiment capable of enhancing the signals of such static samples, by transferring dipolar order from surrounding, highly polarized protons. The experiment, which we dub Dipolar-Order-based BRoadband Adiabatic INversion Cross-Polarization (DOBRAIN-CP), utilizes a Freeman-Kupče broadband inversion WURST pulse to perform CP over the wideline spectrum of the low receptivity species, while matching the low frequencies associated to <sup>1</sup>H<img><sup>1</sup>H dipolar fields. We present analytical and numerical analyses of the spin-dynamics of DOBRAIN-CP for spin-½ nuclei, as well as for quadrupolar spins. Experimental results are also presented for spin-½, integer and half-integer quadrupolar spins; these show that although DOBRAIN-CP delivers broadband excitation and sensitivity enhancement compared to direct excitations, it does not exceed the sensitivity enhancement of the BRAIN-CP variant based on Hartmann-Hahn matching. The power requirements for DOBRAIN-CP are extremely low, yet long dipolar-order lifetimes T<sub>1D</sub> are needed to support the DOBRAIN-CP build-up times.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"373 ","pages":"Article 107860"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Complete characterization of 13C chemical shift tensor in magnetically oriented microcrystal suspension (MOMS) is demonstrated with an inhouse 1H-13C double resonance probe capable of rotating microcrystals and of tilting the sample temporarily during the period of NMR signal acquisition. The 13C chemical shift tensor in three-dimensional MOMS of l-alanine is determined from 13C rotation patterns around a tilted axis. The present results prove that even for micrometer-sized microcrystals the chemical shift tensor can be fully determined like in the case of a single piece of bulky crystal but without elaborate sample mounting. Two-dimensional experiments correlating chemical shifts for different sample orientations are also demonstrated.
{"title":"Full determination of chemical shift tensor in magnetically oriented microcrystals with modulated rotation and temporal tilt","authors":"Ryosuke Kusumi , Hayate Yasui , Hiroshi Kadoma , Masahisa Wada , Kazuyuki Takeda","doi":"10.1016/j.jmr.2025.107853","DOIUrl":"10.1016/j.jmr.2025.107853","url":null,"abstract":"<div><div>Complete characterization of <sup>13</sup>C chemical shift tensor in magnetically oriented microcrystal suspension (MOMS) is demonstrated with an inhouse <sup>1</sup>H-<sup>13</sup>C double resonance probe capable of rotating microcrystals and of tilting the sample temporarily during the period of NMR signal acquisition. The <sup>13</sup>C chemical shift tensor in three-dimensional MOMS of <span>l</span>-alanine is determined from <sup>13</sup>C rotation patterns around a tilted axis. The present results prove that even for micrometer-sized microcrystals the chemical shift tensor can be fully determined like in the case of a single piece of bulky crystal but without elaborate sample mounting. Two-dimensional experiments correlating chemical shifts for different sample orientations are also demonstrated.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"373 ","pages":"Article 107853"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dynamic nuclear polarization (DNP) is widely used in a wide range of applications in solid-state NMR nowadays due to recent advancements of magic-angle spinning (MAS) DNP. Conventionally, an MAS-DNP system employs a gyrotron as a microwave source and operates at 100 K using nitrogen gas. As an alternative, we present a 400 MHz/263 GHz MAS-DNP system utilizing a compact solid-state microwave source and an ultra-low temperature (ULT) helium MAS probe equipped with a cryogenic preamplifier. Compared to gyrotrons, solid-state microwave sources are compact, cost-effective, and frequency agile. The ULT compensates for the decreased DNP efficiency resulting from the lower microwave power of the solid-state source. Additionally, the large Boltzmann polarization at ULT and the improved signal-to-noise ratio provided by the cryogenic preamplifier enhance the sensitivity of the MAS-DNP system. The system is tested using a DNP standard sample of proline in a mixture of deuterated glycerol and partially deuterated water doped with AMUPol, achieving a DNP enhancement of 85 using a 2 mm-diameter rotor at a sample temperature of 30 K and microwave power of 160 mW. Experimental data show that the Boltzmann polarization and the cryogenic preamplifier contribute an additional sensitivity gain of 11 at 30 K compared to 100 K. Overall, the ULT-DNP related sensitivity gain of this system is estimated to be roughly twice that of a 100 K gyrotron system, although the DNP enhancement factor alone is smaller using a solid-state microwave source.
{"title":"400 MHz/263 GHz ultra-low temperature MAS-DNP using a closed-cycle helium gas cooling system and a solid-state microwave source","authors":"Fumio Hobo , Yusuke Tanimoto , Yuki Endo , Yoh Matsuki , Hiroki Takahashi","doi":"10.1016/j.jmr.2025.107842","DOIUrl":"10.1016/j.jmr.2025.107842","url":null,"abstract":"<div><div>Dynamic nuclear polarization (DNP) is widely used in a wide range of applications in solid-state NMR nowadays due to recent advancements of magic-angle spinning (MAS) DNP. Conventionally, an MAS-DNP system employs a gyrotron as a microwave source and operates at <span><math><mo>∼</mo></math></span>100 K using nitrogen gas. As an alternative, we present a 400 MHz/263 GHz MAS-DNP system utilizing a compact solid-state microwave source and an ultra-low temperature (ULT) helium MAS probe equipped with a cryogenic preamplifier. Compared to gyrotrons, solid-state microwave sources are compact, cost-effective, and frequency agile. The ULT compensates for the decreased DNP efficiency resulting from the lower microwave power of the solid-state source. Additionally, the large Boltzmann polarization at ULT and the improved signal-to-noise ratio provided by the cryogenic preamplifier enhance the sensitivity of the MAS-DNP system. The system is tested using a DNP standard sample of proline in a mixture of deuterated glycerol and partially deuterated water doped with AMUPol, achieving a DNP enhancement of 85 using a 2 mm-diameter rotor at a sample temperature of 30 K and microwave power of 160 mW. Experimental data show that the Boltzmann polarization and the cryogenic preamplifier contribute an additional sensitivity gain of 11<span><math><mo>×</mo></math></span> at 30 K compared to 100 K. Overall, the ULT-DNP related sensitivity gain of this system is estimated to be roughly twice that of a 100 K gyrotron system, although the DNP enhancement factor alone is smaller using a solid-state microwave source.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"373 ","pages":"Article 107842"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-12DOI: 10.1016/j.jmr.2024.107828
Perttu Hilla, Juha Vaara
Spin relaxation is modelled using the so-called relaxation superoperator . Analytic forms of have been derived in the literature in the simplest cases of one- or two-spin systems, with nuclei and no more than two different simultaneous relaxation mechanisms involved. Beyond that, for systems of more than two spins, with and/or multiple relaxation mechanisms at play, the derivations become notoriously complicated, which is why analytic relaxation theory has mostly been considered a dead end. Instead, numerical methods of constructing have been popular. However, they lack some of the physical, chemical and pedagogical insight that can be provided by analytic expressions. To this end, we present a general, interactive and freely available Python programme, named Rela2x, to automatically compute the analytic matrix representation of for high-field NMR. Tools to analyse, approximate and visualize are built into Rela2x. As a demonstration of the functionality, is presented both for the familiar dipole–dipole coupled H-H spin system and for more complicated H-14N and H-13C-14N systems with dipole–dipole coupling, chemical shift anisotropy and quadrupole interaction. We envision that the code will provide much-needed clarity in the form of a helpful tool for the study of relaxation effects, and constitute a reference source for scientists in the field of NMR.
{"title":"Rela2x: Analytic and automatic NMR relaxation theory","authors":"Perttu Hilla, Juha Vaara","doi":"10.1016/j.jmr.2024.107828","DOIUrl":"10.1016/j.jmr.2024.107828","url":null,"abstract":"<div><div>Spin relaxation is modelled using the so-called relaxation superoperator <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span>. Analytic forms of <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span> have been derived in the literature in the simplest cases of one- or two-spin systems, with <span><math><mrow><mi>S</mi><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span> nuclei and no more than two different simultaneous relaxation mechanisms involved. Beyond that, for systems of more than two spins, with <span><math><mrow><mi>S</mi><mo>></mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span> and/or multiple relaxation mechanisms at play, the derivations become notoriously complicated, which is why analytic relaxation theory has mostly been considered a dead end. Instead, numerical methods of constructing <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span> have been popular. However, they lack some of the physical, chemical and pedagogical insight that can be provided by analytic expressions. To this end, we present a general, interactive and freely available Python programme, named <span>Rela<sup>2</sup>x</span>, to automatically compute the analytic matrix representation of <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span> for high-field NMR. Tools to analyse, approximate and visualize <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span> are built into <span>Rela<sup>2</sup>x</span>. As a demonstration of the functionality, <span><math><mover><mrow><mover><mrow><mi>Γ</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span> is presented both for the familiar dipole–dipole coupled <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H-<span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H spin system and for more complicated <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H-<sup>14</sup>N and <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H-<sup>13</sup>C-<sup>14</sup>N systems with dipole–dipole coupling, chemical shift anisotropy and quadrupole interaction. We envision that the code will provide much-needed clarity in the form of a helpful tool for the study of relaxation effects, and constitute a reference source for scientists in the field of NMR.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"372 ","pages":"Article 107828"},"PeriodicalIF":2.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143019074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-17DOI: 10.1016/j.jmr.2025.107831
Minchae Kwak , Minji Kim , Dong-Hyun Peck , Seong-Joo Lee , Jeong Hyun Shim , Oc Hee Han , Jung Ho Lee
Most NMR samples are cylindrical, which is ideal for obtaining high-resolution NMR spectra, especially in superconducting magnets with a vertical bore. However, expanding NMR applicability to samples that are not necessarily cylindrical requires a new approach. In this study, we introduce a method for obtaining solution NMR signals from flat samples, such as flat containers or layered structures like a fuel cell. A flat rectangular NMR coil was developed for RF application and sensitive signal detection, while biplanar shim coils were designed using Bfieldtools and manufactured on multilayered printed circuit boards to improve NMR resolution. Water and ethanol molecules in flat rectangular and flat circular containers, as well as in a direct ethanol fuel cell, were observed with narrow NMR linewidths. We believe that our spectrometer design will enable NMR analysis of samples that need to be contained in flat structures and support in-situ analysis of various devices.
{"title":"Observation of NMR signals from samples with flat geometry: Application to in-situ analysis of a direct ethanol fuel cell","authors":"Minchae Kwak , Minji Kim , Dong-Hyun Peck , Seong-Joo Lee , Jeong Hyun Shim , Oc Hee Han , Jung Ho Lee","doi":"10.1016/j.jmr.2025.107831","DOIUrl":"10.1016/j.jmr.2025.107831","url":null,"abstract":"<div><div>Most NMR samples are cylindrical, which is ideal for obtaining high-resolution NMR spectra, especially in superconducting magnets with a vertical bore. However, expanding NMR applicability to samples that are not necessarily cylindrical requires a new approach. In this study, we introduce a method for obtaining solution NMR signals from flat samples, such as flat containers or layered structures like a fuel cell. A flat rectangular NMR coil was developed for RF application and sensitive signal detection, while biplanar shim coils were designed using Bfieldtools and manufactured on multilayered printed circuit boards to improve NMR resolution. Water and ethanol molecules in flat rectangular and flat circular containers, as well as in a direct ethanol fuel cell, were observed with narrow NMR linewidths. We believe that our spectrometer design will enable NMR analysis of samples that need to be contained in flat structures and support <em>in-situ</em> analysis of various devices.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"372 ","pages":"Article 107831"},"PeriodicalIF":2.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143019071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-23DOI: 10.1016/j.jmr.2025.107840
Dennis J. Sorce , Shalom Michaeli
In this work the effect of the geometric phase on time evolution of the density matrix was evaluated during nonadiabatic radiofrequency (RF) pulses with Sine amplitude modulation (AM) and Cosine frequency modulation (FM) functions of the RAFF (Relaxations Along a Fictitious Field) family, and the polarization between two energy level ½ spin system coupled by dipolar interaction was evaluated during the application of RF irradiation. The dependencies of the diagonal density matrix elements and the polarization on the rotational correlation times and the time during RF pulses were evaluated. The general treatment of the density matrix elements along with the polarization generated during RF pulses was unavailable thus far, and for the first time was here derived for the nonadiabatic case of the RAFF pulses. The current formalism could be extended to other AM and FM RF waveforms, including the adiabatic RF pulses which are widely used in magnetic resonance (MR). We demonstrate that the sub-geometric phases (SGP) influence the density matrix elements and thus the polarization generated during the application of RF AM and FM pulses. The corrections to describe the SGP influence of the density matrix elements developed in this work could be essential for determination of MR fundamental parameters necessary for evaluation of tissue contrasts in vivo in MRI and for protein dynamics characterization in high resolution NMR, where AM and FM RF pulses are frequently utilized.
{"title":"On the geometric phase effects on time evolution of the density matrix during modulated radiofrequency pulses","authors":"Dennis J. Sorce , Shalom Michaeli","doi":"10.1016/j.jmr.2025.107840","DOIUrl":"10.1016/j.jmr.2025.107840","url":null,"abstract":"<div><div>In this work the effect of the geometric phase on time evolution of the density matrix was evaluated during nonadiabatic radiofrequency (RF) pulses with <em>Sine</em> amplitude modulation (AM) and <em>Cosine</em> frequency modulation (FM) functions of the RAFF (Relaxations Along a Fictitious Field) family, and the polarization between two energy level ½ spin system coupled by dipolar interaction was evaluated during the application of RF irradiation. The dependencies of the diagonal density matrix elements and the polarization on the rotational correlation times and the time during RF pulses were evaluated. The general treatment of the density matrix elements along with the polarization generated during RF pulses was unavailable thus far, and for the first time was here derived for the nonadiabatic case of the RAFF pulses. The current formalism could be extended to other AM and FM RF waveforms, including the adiabatic RF pulses which are widely used in magnetic resonance (MR). We demonstrate that the sub-geometric phases (SGP) influence the density matrix elements and thus the polarization generated during the application of RF AM and FM pulses. The corrections to describe the SGP influence of the density matrix elements developed in this work could be essential for determination of MR fundamental parameters necessary for evaluation of tissue contrasts <em>in vivo</em> in MRI and for protein dynamics characterization in high resolution NMR, where AM and FM RF pulses are frequently utilized.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"372 ","pages":"Article 107840"},"PeriodicalIF":2.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143043801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2025-01-12DOI: 10.1016/j.jmr.2025.107830
Agide Gimenez Marassi , Arthur Gustavo de Araújo-Ferreira , Everton Lucas-Oliveira , Aparecido Donizeti Fernandes de Amorim , Edson Luiz Géa Vidoto , Willian Andrighetto Trevizan , Tito José Bonagamba
Among the numerous measurements carried out during a well-logging procedure, the Nuclear Magnetic Resonance (NMR) assessment is one of the fundamental analyses in determining the economic viability of a well for the oil industry. Nowadays, two reliable approaches, Wireline Logging (WL) and Logging While Drilling (LWD), stand out. WL comprises the acquisition of NMR data under static conditions. On the other hand, in LWD, the NMR measurements happen simultaneously with the drilling process, while the NMR tool experiences translation, rotation, and vibration motions relative to the rock formation. In order to comprehend better the NMR response acquired under LWD conditions, a setup emulating an LWD tool was developed, consisting of a single-sided magnet, rf probes, and a mechanical device that emulates a relative sinusoidal movement between the sample and the applied magnetic field. A bulk sample and three representative rocks, Fontainebleau Sandstone, Berea Sandstone, and Indiana Limestone, were investigated. Even though the diffusion coefficient measurements remain neglected for their intrinsic characteristics of data acquisition, the findings demonstrate that the diffusion coefficient parameter of a fluid in a bulk sample or confined in a porous rock can be precise and accurately predicted. In strong magnetic field gradients, the Hahn spin echo is predominantly weighted by the diffusion process, an effect used to measure diffusion coefficients. Under LWD conditions, the diffusion coefficient measurement is considerably affected by signal phase modulation due to sample movement in the presence of strong magnetic field gradients, making this measurement difficult. This article present solutions for correct diffusion coefficient measurements, synchronizing Hahn spin echo experiments with sample movement.
{"title":"Diffusion coefficient measurements for moving samples under strong magnetic field gradients","authors":"Agide Gimenez Marassi , Arthur Gustavo de Araújo-Ferreira , Everton Lucas-Oliveira , Aparecido Donizeti Fernandes de Amorim , Edson Luiz Géa Vidoto , Willian Andrighetto Trevizan , Tito José Bonagamba","doi":"10.1016/j.jmr.2025.107830","DOIUrl":"10.1016/j.jmr.2025.107830","url":null,"abstract":"<div><div>Among the numerous measurements carried out during a well-logging procedure, the Nuclear Magnetic Resonance (NMR) assessment is one of the fundamental analyses in determining the economic viability of a well for the oil industry. Nowadays, two reliable approaches, Wireline Logging (WL) and Logging While Drilling (LWD), stand out. WL comprises the acquisition of NMR data under static conditions. On the other hand, in LWD, the NMR measurements happen simultaneously with the drilling process, while the NMR tool experiences translation, rotation, and vibration motions relative to the rock formation. In order to comprehend better the NMR response acquired under LWD conditions, a setup emulating an LWD tool was developed, consisting of a single-sided magnet, rf probes, and a mechanical device that emulates a relative sinusoidal movement between the sample and the applied magnetic field. A bulk sample and three representative rocks, Fontainebleau Sandstone, Berea Sandstone, and Indiana Limestone, were investigated. Even though the diffusion coefficient measurements remain neglected for their intrinsic characteristics of data acquisition, the findings demonstrate that the diffusion coefficient parameter of a fluid in a bulk sample or confined in a porous rock can be precise and accurately predicted. In strong magnetic field gradients, the Hahn spin echo is predominantly weighted by the diffusion process, an effect used to measure diffusion coefficients. Under LWD conditions, the diffusion coefficient measurement is considerably affected by signal phase modulation due to sample movement in the presence of strong magnetic field gradients, making this measurement difficult. This article present solutions for correct diffusion coefficient measurements, synchronizing Hahn spin echo experiments with sample movement.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"371 ","pages":"Article 107830"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-11-22DOI: 10.1016/j.jmr.2024.107810
Stephen Wimperis , Galina E. Pavlovskaya
Double-quantum filtered 23Na NMR experiments with one or two “magic angle” (54.7°) pulses in the filter step are widely used for selective observation of sodium ions that are interacting with ordered biological structures (“ordered sodium”) and hence exhibit a distribution of quadrupolar splittings in their NMR spectrum. This approach has recently been extended to 23Na MRI where the conventional experiment has been modified, omitting the 180° pulse to reduce the absorption of radiofrequency energy during human studies. Here, the “magic angle” double-quantum filtered 23Na NMR experiment (without a 180° pulse) is analysed in terms of coherence pathways that lead to refocusing in an inhomogeneous B0 field (“echoes”) and those that do not (“antiechoes”). It is shown that the echo and antiecho pathways can be separated by phase cycling and that the antiecho pathway contributes very little to the overall signal in an inhomogeneous B0 field. Hence, a double-quantum filtered 23Na NMR experiment that utilises just the echo pathway and so achieves complete refocusing of the effects of B0 inhomogeneity without making use of a 180° pulse is proposed. The new method is demonstrated both in 23Na NMR spectroscopy in an inhomogeneous B0 field and in 23Na MRI of a three-component phantom.
{"title":"Double-quantum filtered 23Na NMR and MRI: Selective detection of ordered sodium in an inhomogeneous B0 field","authors":"Stephen Wimperis , Galina E. Pavlovskaya","doi":"10.1016/j.jmr.2024.107810","DOIUrl":"10.1016/j.jmr.2024.107810","url":null,"abstract":"<div><div>Double-quantum filtered <sup>23</sup>Na NMR experiments with one or two “magic angle” (54.7°) pulses in the filter step are widely used for selective observation of sodium ions that are interacting with ordered biological structures (“ordered sodium”) and hence exhibit a distribution of quadrupolar splittings in their NMR spectrum. This approach has recently been extended to <sup>23</sup>Na MRI where the conventional experiment has been modified, omitting the 180° pulse to reduce the absorption of radiofrequency energy during human studies. Here, the “magic angle” double-quantum filtered <sup>23</sup>Na NMR experiment (without a 180° pulse) is analysed in terms of coherence pathways that lead to refocusing in an inhomogeneous B<sub>0</sub> field (“echoes”) and those that do not (“antiechoes”). It is shown that the echo and antiecho pathways can be separated by phase cycling and that the antiecho pathway contributes very little to the overall signal in an inhomogeneous B<sub>0</sub> field. Hence, a double-quantum filtered <sup>23</sup>Na NMR experiment that utilises just the echo pathway and so achieves complete refocusing of the effects of B<sub>0</sub> inhomogeneity without making use of a 180° pulse is proposed. The new method is demonstrated both in <sup>23</sup>Na NMR spectroscopy in an inhomogeneous B<sub>0</sub> field and in <sup>23</sup>Na MRI of a three-component phantom.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"371 ","pages":"Article 107810"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142911313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-12-27DOI: 10.1016/j.jmr.2024.107827
Mária Šoltésová , Arthur C. Pinon , Fabien Aussenac , Judith Schlagnitweit , Christian Reiter , Armin Purea , Roberto Melzi , Frank Engelke , Dave Martin , Stefanie Krambeck , Annabelle Biscans , Emma Kay , Lyndon Emsley , Staffan Schantz
A new 3.2 mm 1H–19F–X magic angle spinning dynamic nuclear polarization NMR (MAS DNP-NMR) probe was developed with a unique coil design with separate radiofrequency channels for 1H excitation and 13C or 19F detection to enable acquisition of 1H–19F cross-polarization (CP) MAS experiments, direct-detected 19F spectra with proton decoupling, and acquisition on 13C with simultaneous double decoupling on the 1H and 19F channels as well as 1H–19F–13C double-CP experiments under low temperature MAS DNP conditions. We use these sequences to study AZD2811, which is an active pharmaceutical ingredient (API), in its pure dry state as well as in its corresponding drug delivery formulation consisting of drug-loaded polymeric nanoparticles (PNPs). Included in this study are also small interfering RNAs (siRNAs) for therapeutic targeting of peptidyl-prolyl cis–trans isomerase B (Ppib) mRNA. We demonstrate that 1H–19F CP MAS experiments performed on the new HFX probe represent a notable advantage over usually acquired direct-detected 19F experiments. The indirect 19F DNP enhancement εon/off(19F) = 26 was obtained via 1H–19F CP for the pure API impregnated with DNP solution, with an overall 30-fold sensitivity gain compared to the direct-detected 19F experiment under similar conditions. DNP enhancement value of εon/off(19F) = 42 was obtained via 1H–19F CP for the polymeric nanoparticle suspension and εon/off(19F) ≈ 150 were obtained for two different siRNAs in frozen DNP solution.
{"title":"1H–19F cross-polarization magic angle spinning dynamic nuclear polarization NMR investigation of advanced pharmaceutical formulations","authors":"Mária Šoltésová , Arthur C. Pinon , Fabien Aussenac , Judith Schlagnitweit , Christian Reiter , Armin Purea , Roberto Melzi , Frank Engelke , Dave Martin , Stefanie Krambeck , Annabelle Biscans , Emma Kay , Lyndon Emsley , Staffan Schantz","doi":"10.1016/j.jmr.2024.107827","DOIUrl":"10.1016/j.jmr.2024.107827","url":null,"abstract":"<div><div>A new 3.2 mm <sup>1</sup>H–<sup>19</sup>F–X magic angle spinning dynamic nuclear polarization NMR (MAS DNP-NMR) probe was developed with a unique coil design with separate radiofrequency channels for <sup>1</sup>H excitation and <sup>13</sup>C or <sup>19</sup>F detection to enable acquisition of <sup>1</sup>H–<sup>19</sup>F cross-polarization (CP) MAS experiments, direct-detected <sup>19</sup>F spectra with proton decoupling, and acquisition on <sup>13</sup>C with simultaneous double decoupling on the <sup>1</sup>H and 19F channels as well as <sup>1</sup>H–<sup>19</sup>F–<sup>13</sup>C double-CP experiments under low temperature MAS DNP conditions. We use these sequences to study AZD2811, which is an active pharmaceutical ingredient (API), in its pure dry state as well as in its corresponding drug delivery formulation consisting of drug-loaded polymeric nanoparticles (PNPs). Included in this study are also small interfering RNAs (siRNAs) for therapeutic targeting of peptidyl-prolyl <em>cis–trans</em> isomerase B (<em>Ppib</em>) mRNA. We demonstrate that <sup>1</sup>H–<sup>19</sup>F CP MAS experiments performed on the new HFX probe represent a notable advantage over usually acquired direct-detected <sup>19</sup>F experiments. The indirect <sup>19</sup>F DNP enhancement ε<sub>on/off</sub>(<sup>19</sup>F) = 26 was obtained via <sup>1</sup>H–<sup>19</sup>F CP for the pure API impregnated with DNP solution, with an overall 30-fold sensitivity gain compared to the direct-detected <sup>19</sup>F experiment under similar conditions. DNP enhancement value of ε<sub>on/off</sub>(<sup>19</sup>F) = 42 was obtained via <sup>1</sup>H–<sup>19</sup>F CP for the polymeric nanoparticle suspension and ε<sub>on/off</sub>(<sup>19</sup>F) ≈ 150 were obtained for two different siRNAs in frozen DNP solution.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"371 ","pages":"Article 107827"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2025-01-13DOI: 10.1016/j.jmr.2025.107829
Matthew M. Willmering , Brice J. Albert , Joseph W. Plummer , Josh Greer , Laura L. Walkup , Diana M. Lindquist , Zackary I. Cleveland
Harmonizing and validating 129Xe gas exchange imaging across multiple sites is hampered by a lack of a quantitative standard that 1) displays the unique spectral properties of 129Xe observed from human subjects in vivo and 2) has short enough times to enable practical imaging. This work describes and demonstrates the development of two dissolved-phase, thermally polarized phantoms that mimic the in-vivo, red blood cell and membrane resonances of 129Xe dissolved in human lungs. Following optimization, combinations of two common organic solvents, acetone and dimethyl sulfoxide, resulted in two in-vivo-like dissolved-phase 129Xe phantoms yielding chemical shifts of 212.4 ppm and 193.9 ppm. By doping the solutions with iron(iii) acetylacetonate, the longitudinal relaxation time was reduced = 1.2 s for both phantoms at 3 T and 7 T. There was minimal change in chemical shift (+1.58 ppm) and (+1.2 %) over 1 year. In a 2D Dixon-type acquisition with 3 mm2 in-plane resolution, 129Xe dissolved-phase images yielded signal-to-noise ratios 6 and 12 for the RBC and membrane phantoms, respectively. A simple scaling of these phantoms to clinically relevant volumes of several liters would result in an SNR of 7 for the RBC phantom acquired in less than one minute. These findings demonstrate the ability to fabricate robust, quantitative, thermally polarized dissolved-phase phantoms, which will be needed to validate and harmonize gas exchange imaging in multi-site clinical trials.
{"title":"A thermally polarized, dissolved-phase 129Xe phantom for quality-control and multisite comparisons of gas-exchange imaging","authors":"Matthew M. Willmering , Brice J. Albert , Joseph W. Plummer , Josh Greer , Laura L. Walkup , Diana M. Lindquist , Zackary I. Cleveland","doi":"10.1016/j.jmr.2025.107829","DOIUrl":"10.1016/j.jmr.2025.107829","url":null,"abstract":"<div><div>Harmonizing and validating <sup>129</sup>Xe gas exchange imaging across multiple sites is hampered by a lack of a quantitative standard that 1) displays the unique spectral properties of <sup>129</sup>Xe observed from human subjects <em>in vivo</em> and 2) has short enough <span><math><msub><mi>T</mi><mn>1</mn></msub></math></span> times to enable practical imaging. This work describes and demonstrates the development of two dissolved-phase, thermally polarized phantoms that mimic the <em>in-vivo</em>, red blood cell and membrane resonances of <sup>129</sup>Xe dissolved in human lungs. Following optimization, combinations of two common organic solvents, acetone and dimethyl sulfoxide, resulted in two <em>in-vivo</em>-like dissolved-phase <sup>129</sup>Xe phantoms yielding chemical shifts of 212.4 ppm and 193.9 ppm. By doping the solutions with iron(iii) acetylacetonate, the longitudinal relaxation time was reduced <span><math><msub><mi>T</mi><mn>1</mn></msub></math></span> = 1.2 s for both phantoms at 3 T and 7 T. There was minimal change in chemical shift (+1.58 ppm) and <span><math><msub><mi>T</mi><mn>1</mn></msub></math></span> (+1.2 %) over 1 year. In a 2D Dixon-type acquisition with 3 mm<sup>2</sup> in-plane resolution, <sup>129</sup>Xe dissolved-phase images yielded signal-to-noise ratios 6 and 12 for the RBC and membrane phantoms, respectively. A simple scaling of these phantoms to clinically relevant volumes of several liters would result in an SNR of 7 for the RBC phantom acquired in less than one minute. These findings demonstrate the ability to fabricate robust, quantitative, thermally polarized dissolved-phase phantoms, which will be needed to validate and harmonize gas exchange imaging in multi-site clinical trials.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"371 ","pages":"Article 107829"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142985694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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