Pub Date : 2025-02-01DOI: 10.1016/j.jmro.2025.100189
Bowen Han , Jing He , Shaohua Huang
Chiral amino acids play an indispensable role in living organisms. Diffusion-ordered NMR spectroscopy is an effective NMR tool and a noninvasive analytical method for the analyses of mixture without the need for physical separation of the analytes. However, conventional diffusion-ordered NMR spectroscopy method usually fails to resolve the mixtures of chiral amino acids because of their same molecular masses, sizes, and shapes. Microcrystalline cellulose has been gradually gained more and more interest owing to its wide compatibility, surface area, excellent separation efficiency, non-toxicity, cost-effective, and mechanical stability in many fields. Herein we provide a fast, simple, specific and sensitive method to resolve some D and L-amino acids mixtures by using microcrystalline cellulose as a matrix. This work recognized some D and L- proteinogenic amino acid enantiomers with diffusion-ordered NMR for the first time.
{"title":"Chiral recognition of some D and L-amino acids by microcrystalline cellulose assisted diffusion-ordered NMR spectroscopy","authors":"Bowen Han , Jing He , Shaohua Huang","doi":"10.1016/j.jmro.2025.100189","DOIUrl":"10.1016/j.jmro.2025.100189","url":null,"abstract":"<div><div>Chiral amino acids play an indispensable role in living organisms. Diffusion-ordered NMR spectroscopy is an effective NMR tool and a noninvasive analytical method for the analyses of mixture without the need for physical separation of the analytes. However, conventional diffusion-ordered NMR spectroscopy method usually fails to resolve the mixtures of chiral amino acids because of their same molecular masses, sizes, and shapes. Microcrystalline cellulose has been gradually gained more and more interest owing to its wide compatibility, surface area, excellent separation efficiency, non-toxicity, cost-effective, and mechanical stability in many fields. Herein we provide a fast, simple, specific and sensitive method to resolve some D and L-amino acids mixtures by using microcrystalline cellulose as a matrix. This work recognized some D and L- proteinogenic amino acid enantiomers with diffusion-ordered NMR for the first time.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100189"},"PeriodicalIF":2.624,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1016/j.jmro.2025.100190
Ditte Bentsen Christensen , Ingeborg Sæten Skre , Jan Henrik Ardenkjær-Larsen , Mor Mishkovsky , Mathilde H Lerche
Metabolic magnetic resonance spectroscopic imaging using hyperpolarized contrast agents offers a non-invasive approach to monitoring real-time in vivo energy metabolism. The technique involves hyperpolarizing a contrast agent in a polarizer, administering it to a living system, and then imaging its distribution and metabolites using a magnetic resonance scanner. Over the past two decades, the method has transitioned from in vitro studies to clinical research, with an increasing focus on clinical applications.
Here, we present a hybrid system that adapts a clinical magnetic resonance scanner for pre-clinical rodent experiments. The hybrid system includes (1) a customizable, 3D-printable animal cradle setup and (2) optimized imaging strategies, including coil configurations, metabolic contrast agent administration, and proton imaging acquisition. The system enables 13C dynamic imaging, which we illustrate with detection of hyperpolarized [1–13C]pyruvate and its metabolites in the mouse brain. We detail the experimental procedure, provide practical guidance, and showcase the capabilities of the system with example data from mouse brain imaging.
This hybrid setup bridges the gap between clinical and pre-clinical research, enabling iterative testing of equipment, imaging sequences, and hypotheses across phantoms, in vivo rodent models and clinical settings. By facilitating a smoother translation, both forward and reverse, between pre-clinical and clinical applications, this approach enhances the potential for advancing metabolic imaging research.
{"title":"A hybrid setup for rodent hyperpolarized metabolic imaging using a clinical magnetic resonance scanner","authors":"Ditte Bentsen Christensen , Ingeborg Sæten Skre , Jan Henrik Ardenkjær-Larsen , Mor Mishkovsky , Mathilde H Lerche","doi":"10.1016/j.jmro.2025.100190","DOIUrl":"10.1016/j.jmro.2025.100190","url":null,"abstract":"<div><div>Metabolic magnetic resonance spectroscopic imaging using hyperpolarized contrast agents offers a non-invasive approach to monitoring real-time in vivo energy metabolism. The technique involves hyperpolarizing a contrast agent in a polarizer, administering it to a living system, and then imaging its distribution and metabolites using a magnetic resonance scanner. Over the past two decades, the method has transitioned from in vitro studies to clinical research, with an increasing focus on clinical applications.</div><div>Here, we present a hybrid system that adapts a clinical magnetic resonance scanner for pre-clinical rodent experiments. The hybrid system includes (1) a customizable, 3D-printable animal cradle setup and (2) optimized imaging strategies, including coil configurations, metabolic contrast agent administration, and proton imaging acquisition. The system enables <sup>13</sup>C dynamic imaging, which we illustrate with detection of hyperpolarized [1–<sup>13</sup>C]pyruvate and its metabolites in the mouse brain. We detail the experimental procedure, provide practical guidance, and showcase the capabilities of the system with example data from mouse brain imaging.</div><div>This hybrid setup bridges the gap between clinical and pre-clinical research, enabling iterative testing of equipment, imaging sequences, and hypotheses across phantoms, in vivo rodent models and clinical settings. By facilitating a smoother translation, both forward and reverse, between pre-clinical and clinical applications, this approach enhances the potential for advancing metabolic imaging research.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100190"},"PeriodicalIF":2.624,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143353597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.jmro.2025.100187
D. Levi Love, Michael R. Gryk, Adam D. Schuyler
In pursuit of an adaptive approach to nonuniform sampling (NUS), two critical determinants arise: (1) the ability to determine an endpoint by way of quantitatively assessing spectral quality and (2) the ability to systematically determine what additional FIDs to collect if the aforementioned stop criteria is not met. As previously established, in situ receiver operator characteristic (IROC, (Zambrello et al., 2017)) assesses the recovery of injected synthetic ground truth signals to define spectral quality. The Nonuniform Sampling Contest (NUScon, (Pustovalova et al., 2021)), defines a workflow for processing NUS experiments and quantitatively evaluating spectral quality. We augmented that workflow by including an IROC module, which we believe to be an effective component of defining stop criteria for adaptive FID collection. As for the decision of what additional FIDs, this study builds off the work of prior studies on the influence the seed used to generate a nonuniform sample schedule has on the quality of a NUS reconstruction (Hyberts et al., 2011), i.e., whether a sampling method yields “high-variance” or “low-variance” schedules (Zambrello et al., 2020). Namely, existing work has been focused on reducing seed-dependence (Eddy et al., 2012; Mobli, 2015; Worley, 2016) or “optimizing” the seed (Hyberts and Wagner, 2022) by evaluating sample schedules using a computationally inexpensive metric based on the characterization of the point-spread function, like sidelobe-to-peak ratio (Lustig et al., 2007) and peak-to-sidelobe ratio (PSR, (Eddy et al., 2012; Mobli, 2015; Worley, 2016; Craft et al., 2018)). This study assesses the ability of PSR, an a priori metric that is based solely on the nonuniform sample schedule, to predict spectral quality as assessed by IROC. This work uses IROC to show that seed optimization via PSR does not result in better quality spectra. In addition, the trends observed in the spectral quality reported by IROC informs our future designs for adaptive FID selection.
{"title":"Evaluating metrics of spectral quality in nonuniform sampling","authors":"D. Levi Love, Michael R. Gryk, Adam D. Schuyler","doi":"10.1016/j.jmro.2025.100187","DOIUrl":"10.1016/j.jmro.2025.100187","url":null,"abstract":"<div><div>In pursuit of an adaptive approach to nonuniform sampling (<strong>NUS</strong>), two critical determinants arise: (1) the ability to determine an endpoint by way of quantitatively assessing spectral quality and (2) the ability to systematically determine what additional FIDs to collect if the aforementioned stop criteria is not met. As previously established, <em>in situ</em> receiver operator characteristic (<strong>IROC</strong>, (Zambrello et al., 2017)) assesses the recovery of injected synthetic ground truth signals to define spectral quality. The Nonuniform Sampling Contest (<strong>NUScon</strong>, (Pustovalova et al., 2021)), defines a workflow for processing NUS experiments and quantitatively evaluating spectral quality. We augmented that workflow by including an IROC module, which we believe to be an effective component of defining stop criteria for adaptive FID collection. As for the decision of what additional FIDs, this study builds off the work of prior studies on the influence the seed used to generate a nonuniform sample schedule has on the quality of a NUS reconstruction (Hyberts et al., 2011), i.e., whether a sampling method yields “high-variance” or “low-variance” schedules (Zambrello et al., 2020). Namely, existing work has been focused on reducing seed-dependence (Eddy et al., 2012; Mobli, 2015; Worley, 2016) or “optimizing” the seed (Hyberts and Wagner, 2022) by evaluating sample schedules using a computationally inexpensive metric based on the characterization of the point-spread function, like sidelobe-to-peak ratio (Lustig et al., 2007) and peak-to-sidelobe ratio (<strong>PSR</strong>, (Eddy et al., 2012; Mobli, 2015; Worley, 2016; Craft et al., 2018)). This study assesses the ability of PSR, an <em>a priori</em> metric that is based solely on the nonuniform sample schedule, to predict spectral quality as assessed by IROC. This work uses IROC to show that seed optimization via PSR does not result in better quality spectra. In addition, the trends observed in the spectral quality reported by IROC informs our future designs for adaptive FID selection.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100187"},"PeriodicalIF":2.624,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.jmro.2025.100186
Haoyu Li , Yifan Song , Yu Yin , Juntao Xia , Yun Chen , Maria Grazia Concilio , Xueqian Kong
The phenomenon of intermolecular multiple-quantum coherences (iMQCs) has been known for decades, mainly for spin-1/2 nuclei. However, the iMQC of 23Na, a spin-3/2 quadrupolar nucleus, has not been studied previously. In this communication, we report the observation of 23Na iMQC signals arising from 23Na–23Na long-range dipolar interaction in the aqueous solutions of various sodium salts. We investigated the iMQC signal in response to different experimental parameters. We also formulated a theoretical model to explain the experimental results. Since sodium ions play important roles in biology and industry, 23Na iMQC experiments could bring new insights into ion dynamics and interactions in solutions.
{"title":"23Na intermolecular multiple-quantum coherences in salt solutions","authors":"Haoyu Li , Yifan Song , Yu Yin , Juntao Xia , Yun Chen , Maria Grazia Concilio , Xueqian Kong","doi":"10.1016/j.jmro.2025.100186","DOIUrl":"10.1016/j.jmro.2025.100186","url":null,"abstract":"<div><div>The phenomenon of intermolecular multiple-quantum coherences (iMQCs) has been known for decades, mainly for spin-1/2 nuclei. However, the iMQC of <sup>23</sup>Na, a spin-3/2 quadrupolar nucleus, has not been studied previously. In this communication, we report the observation of <sup>23</sup>Na iMQC signals arising from <sup>23</sup>Na–<sup>23</sup>Na long-range dipolar interaction in the aqueous solutions of various sodium salts. We investigated the iMQC signal in response to different experimental parameters. We also formulated a theoretical model to explain the experimental results. Since sodium ions play important roles in biology and industry, <sup>23</sup>Na iMQC experiments could bring new insights into ion dynamics and interactions in solutions.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100186"},"PeriodicalIF":2.624,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-27DOI: 10.1016/j.jmro.2024.100184
Ditte B. Christensen , Ingeborg S. Skre , Jan Henrik Ardenkjær-Larsen, Magnus Karlsson, Mathilde H. Lerche
Dissolution Dynamic Nuclear Polarization (dDNP) polarizers have achieved high field strengths and large sample volumes. These advancements necessitate new formulations of hyperpolarized metabolic contrast agents (HMCAs) to enable large animal studies. While several metabolic substrates have been investigated at lower field dDNP and tested as HMCAs in rodents, 13C-labeled pyruvate remains the most studied HMCA and is currently the only one actively used in clinical trials due to its favorable biological and physical properties. Effective human and large animal dDNP formulations require high molar substrate concentrations, low DNP sample viscosity for efficient dissolution, and adequate dilution of the DNP sample to minimize signal decay and maximize HMCA concentration.
We present substrate formulations optimized for high-field polarization and large-volume dissolution. Specifically, we validate the upscaling of [1–13C]pyruvate under high-field conditions and demonstrate that [1–13C]2-keto-isocaproate and [1,4–13C2]fumarate, which have been proven successful in rodent studies, can be formulated to yield high polarization at suitable concentrations and volumes for large animal metabolic MR imaging.
{"title":"Developing hyperpolarized metabolic contrast agents at high field dDNP for large animal research","authors":"Ditte B. Christensen , Ingeborg S. Skre , Jan Henrik Ardenkjær-Larsen, Magnus Karlsson, Mathilde H. Lerche","doi":"10.1016/j.jmro.2024.100184","DOIUrl":"10.1016/j.jmro.2024.100184","url":null,"abstract":"<div><div>Dissolution Dynamic Nuclear Polarization (dDNP) polarizers have achieved high field strengths and large sample volumes. These advancements necessitate new formulations of hyperpolarized metabolic contrast agents (HMCAs) to enable large animal studies. While several metabolic substrates have been investigated at lower field dDNP and tested as HMCAs in rodents, <sup>13</sup>C-labeled pyruvate remains the most studied HMCA and is currently the only one actively used in clinical trials due to its favorable biological and physical properties. Effective human and large animal dDNP formulations require high molar substrate concentrations, low DNP sample viscosity for efficient dissolution, and adequate dilution of the DNP sample to minimize signal decay and maximize HMCA concentration.</div><div>We present substrate formulations optimized for high-field polarization and large-volume dissolution. Specifically, we validate the upscaling of [1–<sup>13</sup>C]pyruvate under high-field conditions and demonstrate that [1–<sup>13</sup>C]2-keto-isocaproate and [1,4–<sup>13</sup>C<sub>2</sub>]fumarate, which have been proven successful in rodent studies, can be formulated to yield high polarization at suitable concentrations and volumes for large animal metabolic MR imaging.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100184"},"PeriodicalIF":2.624,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1016/j.jmro.2024.100183
Lisa M. Fries , Denis Moll , Ruhuai Mei , Theresa L․ K․ Hune , Josef Elsaßer , Stefan Glöggler
Magnetic Resonance Imaging (MRI) is a valuable non-invasive technique widely used in clinical diagnostics; however, its sensitivity is limited, posing challenges in various medical conditions. Hyperpolarization techniques represent a promising approach to dramatically enhance signals in magnetic resonance imaging (MRI) and allow the use endogenous metabolites as contrast media. In this study, we synthesized N-acetyl-alanine ethyl ester as a novel imaging agent and assessed its in vivo imaging capabilities, potentially offering diagnostic and monitoring capabilities for cardiovascular diseases. It is derived from N-acetyl-alanine, an endogenous metabolic end product of protein degradation. The in vivo experiments resulted in high-resolution images of the circulatory system acquired within sub-seconds. Our findings not only highlight the potential preclinical utility of this new, generally available agent, but also advance the frontier of hyperpolarized contrast agents.
{"title":"Assessing a hyperpolarized [1-13C]-labeled alanine derivative enhanced via parahydrogen for in vivo studies","authors":"Lisa M. Fries , Denis Moll , Ruhuai Mei , Theresa L․ K․ Hune , Josef Elsaßer , Stefan Glöggler","doi":"10.1016/j.jmro.2024.100183","DOIUrl":"10.1016/j.jmro.2024.100183","url":null,"abstract":"<div><div>Magnetic Resonance Imaging (MRI) is a valuable non-invasive technique widely used in clinical diagnostics; however, its sensitivity is limited, posing challenges in various medical conditions. Hyperpolarization techniques represent a promising approach to dramatically enhance signals in magnetic resonance imaging (MRI) and allow the use endogenous metabolites as contrast media. In this study, we synthesized N-acetyl-alanine ethyl ester as a novel imaging agent and assessed its <em>in vivo</em> imaging capabilities, potentially offering diagnostic and monitoring capabilities for cardiovascular diseases. It is derived from N-acetyl-alanine, an endogenous metabolic end product of protein degradation. The <em>in vivo</em> experiments resulted in high-resolution images of the circulatory system acquired within sub-seconds. Our findings not only highlight the potential preclinical utility of this new, generally available agent, but also advance the frontier of hyperpolarized contrast agents.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100183"},"PeriodicalIF":2.624,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-10DOI: 10.1016/j.jmro.2024.100182
Yi Ji , Kuizhi Chen , Aijing Hao , Guangjin Hou
Recent advances in the 17O-enrichment techiques and high-resolution nuclear magnetic resonance (NMR) methods have opened new opportunities to utilize 17O NMR to disentangle the zeolitic structure−property relationship that has not been well resolved through traditional 1H, 27Al, and 29Si NMR spectroscopy. Compared with one-dimensional 17O magic angle spinning (MAS) NMR experiments, 1H-17O correlation spectrocopy has become a crucial method for revealing the structures and dynamics of reactive hydroxyl species in zeolites with higher resolution and precision. However, the introduction of 17O can induce changes in 1H MAS NMR signals due to the second-order 1H-17O quadrupolar-dipolar (2nd-QD) cross interaction, which has recently been revealed by us on H-ZSM-5 (H-MFI) zeolites with 10-membered-ring (MR) channels. Herein, we performed various 1H-17O correlation experiments (1H{17O}-J-heteronuclear multiple quantum coherence (HMQC), 1H{17O}-D-HMQC, and 1H→17O-D-RINEPT) on two other types of 17O-enriched zeolites, i.e., H-Mordenite (H-MOR) with 8-/12-MR channels and H-ZSM-35 (H-FER) with 8-/10-MR channels. Notably, unusual 1H-17O correlation signals with tilted patterns and magnetic-field-dependent shifts were observed on both samples and all tested correlation experiments at high fields up to 18.8 T. These observations were further comprehensively explained by theoretical analysis of the 1H-17O quadrupolar-dipolar interaction, thus demonstrating that the 1H-17O 2nd-QD interaction generally affects the 1H and 1H-17O correlation MAS NMR spectra of the dehydrated 17O-enriched zeolites, irrespective of the framework types. Beyond zeolites, the non-ignorable 2nd-QD interaction on NMR spectroscopy can complicate NMR identification of 17O-labeled hydroxyls in many other inorganic materials and biomolecules. The analysis methods proposed in this study are expected to effectively address these challenges and provide clearer insights into such systems.
{"title":"Unveiling the impact of second-order 1H-17O Quadrupolar-Dipolar interaction on solid-state NMR spectroscopy","authors":"Yi Ji , Kuizhi Chen , Aijing Hao , Guangjin Hou","doi":"10.1016/j.jmro.2024.100182","DOIUrl":"10.1016/j.jmro.2024.100182","url":null,"abstract":"<div><div>Recent advances in the <sup>17</sup>O-enrichment techiques and high-resolution nuclear magnetic resonance (NMR) methods have opened new opportunities to utilize <sup>17</sup>O NMR to disentangle the zeolitic structure−property relationship that has not been well resolved through traditional <sup>1</sup>H, <sup>27</sup>Al, and <sup>29</sup>Si NMR spectroscopy. Compared with one-dimensional <sup>17</sup>O magic angle spinning (MAS) NMR experiments, <sup>1</sup>H-<sup>17</sup>O correlation spectrocopy has become a crucial method for revealing the structures and dynamics of reactive hydroxyl species in zeolites with higher resolution and precision. However, the introduction of <sup>17</sup>O can induce changes in <sup>1</sup>H MAS NMR signals due to the second-order <sup>1</sup>H-<sup>17</sup>O quadrupolar-dipolar (2nd-QD) cross interaction, which has recently been revealed by us on H-ZSM-5 (H-MFI) zeolites with 10-membered-ring (MR) channels. Herein, we performed various <sup>1</sup>H-<sup>17</sup>O correlation experiments (<sup>1</sup>H{<sup>17</sup>O}-<em>J</em>-heteronuclear multiple quantum coherence (HMQC), <sup>1</sup>H{<sup>17</sup>O}-<em>D</em>-HMQC, and <sup>1</sup>H→<sup>17</sup>O-<span><em>D</em></span>-RINEPT) on two other types of <sup>17</sup>O-enriched zeolites, i.e., H-Mordenite (H-MOR) with 8-/12-MR channels and H-ZSM-35 (H-FER) with 8-/10-MR channels. Notably, unusual <sup>1</sup>H-<sup>17</sup>O correlation signals with tilted patterns and magnetic-field-dependent shifts were observed on both samples and all tested correlation experiments at high fields up to 18.8 T. These observations were further comprehensively explained by theoretical analysis of the <sup>1</sup>H-<sup>17</sup>O quadrupolar-dipolar interaction, thus demonstrating that the <sup>1</sup>H-<sup>17</sup>O 2nd-QD interaction generally affects the <sup>1</sup>H and <sup>1</sup>H-<sup>17</sup>O correlation MAS NMR spectra of the dehydrated <sup>17</sup>O-enriched zeolites, irrespective of the framework types. Beyond zeolites, the non-ignorable 2nd-QD interaction on NMR spectroscopy can complicate NMR identification of <sup>17</sup>O-labeled hydroxyls in many other inorganic materials and biomolecules. The analysis methods proposed in this study are expected to effectively address these challenges and provide clearer insights into such systems.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100182"},"PeriodicalIF":2.624,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-10DOI: 10.1016/j.jmro.2024.100179
Wolfgang Kilian , Samira Gulich , Thomas Riemer , Lorenz Mitschang
The use of hyperpolarized media in combination with benchtop NMR spectrometers is currently extensively investigated to enable cost effective but highly sensitive applications. In this work, the instrumentation for the use of hyperpolarized 129Xe gas on a commercial benchtop-NMR spectrometer in a fully controllable yet automated mode is presented. A continuous-flow 129Xe polarizer is operated inline with the benchtop spectrometer. While the adjustment of the xenon gas partial pressure in the range of mbar to bar as well as the volume flow through the NMR sample is facilitated by the polarizer’s mass-flow controllers and two back-pressure regulators, respectively, the gas flow towards the NMR sample in situ in the benchtop magnet is time-controlled within the spectrometer’s RF pulse sequence programming. A calibration procedure for the gas flow control as well as thermally polarized xenon gas standards are introduced for quantification of the absolute 129Xe polarization. In this way, the 129Xe polarization achieved in the NMR measurement is determined in the 50% to 5% regime for very lean 1 mbar to high 500 mbar xenon partial pressure, respectively – in the optimum a more than 250,000-fold increase in comparison to thermal polarization. Such instrumentation may be implemented by combining any of the well-established continuous-flow 129Xe polarizer with any of the commercial benchtop spectrometers, thus facilitating high-performance hyperpolarized 129Xe benchtop NMR studies.
{"title":"Hyperpolarized 129Xe for benchtop NMR: Inline instrumentation for automated yet flexible operation yielding high polarization","authors":"Wolfgang Kilian , Samira Gulich , Thomas Riemer , Lorenz Mitschang","doi":"10.1016/j.jmro.2024.100179","DOIUrl":"10.1016/j.jmro.2024.100179","url":null,"abstract":"<div><div>The use of hyperpolarized media in combination with benchtop NMR spectrometers is currently extensively investigated to enable cost effective but highly sensitive applications. In this work, the instrumentation for the use of hyperpolarized <sup>129</sup>Xe gas on a commercial benchtop-NMR spectrometer in a fully controllable yet automated mode is presented. A continuous-flow <sup>129</sup>Xe polarizer is operated inline with the benchtop spectrometer. While the adjustment of the xenon gas partial pressure in the range of mbar to bar as well as the volume flow through the NMR sample is facilitated by the polarizer’s mass-flow controllers and two back-pressure regulators, respectively, the gas flow towards the NMR sample in situ in the benchtop magnet is time-controlled within the spectrometer’s RF pulse sequence programming. A calibration procedure for the gas flow control as well as thermally polarized xenon gas standards are introduced for quantification of the absolute <sup>129</sup>Xe polarization. In this way, the <sup>129</sup>Xe polarization achieved in the NMR measurement is determined in the 50% to 5% regime for very lean 1<!--> <!-->mbar to high 500<!--> <!-->mbar xenon partial pressure, respectively – in the optimum a more than 250,000-fold increase in comparison to thermal polarization. Such instrumentation may be implemented by combining any of the well-established continuous-flow <sup>129</sup>Xe polarizer with any of the commercial benchtop spectrometers, thus facilitating high-performance hyperpolarized <sup>129</sup>Xe benchtop NMR studies.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100179"},"PeriodicalIF":2.624,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1016/j.jmro.2024.100181
Reiya Yabuki , Koki Nishimura , Yuta Sawada , Masaaki Fuki , Yasuhiro Kobori , Nobuhiro Yanai
Chemically induced dynamic electron polarization (CIDEP) generates radical electron spins with high polarization at room temperature by quenching the photo-excited state of chromophores, which is useful for microwave-free optical dynamic nuclear polarization (DNP) in solution. While nitroxyl (TEMPO) radicals are typically used for this purpose, we show that a tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivative shows greater electron spin polarization than TEMPO by CIDEP using porphyrin chromophores. This is attributed to the longer spin-lattice relaxation time of TTM radicals, with a contribution of efficient quenching of chromophore photo-excited state by energy transfer from the triplet state of porphyrins to the doublet state of the TTM radicals. The porphyrin-TTM pair shows a larger nuclear spin polarization under continuous laser excitation than the porphyrin-TEMPO pair because of the larger polarization and longer spin-lattice relaxation time of the TTM radical electron spins. This work demonstrates the first example of in-solution CIDEP and optically-driven DNP using TTM radicals, opening new opportunities in a wide range of biological and medical applications.
{"title":"Dynamic electron and nuclear spin polarization in solution using porphyrin and tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivatives","authors":"Reiya Yabuki , Koki Nishimura , Yuta Sawada , Masaaki Fuki , Yasuhiro Kobori , Nobuhiro Yanai","doi":"10.1016/j.jmro.2024.100181","DOIUrl":"10.1016/j.jmro.2024.100181","url":null,"abstract":"<div><div>Chemically induced dynamic electron polarization (CIDEP) generates radical electron spins with high polarization at room temperature by quenching the photo-excited state of chromophores, which is useful for microwave-free optical dynamic nuclear polarization (DNP) in solution. While nitroxyl (TEMPO) radicals are typically used for this purpose, we show that a tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivative shows greater electron spin polarization than TEMPO by CIDEP using porphyrin chromophores. This is attributed to the longer spin-lattice relaxation time of TTM radicals, with a contribution of efficient quenching of chromophore photo-excited state by energy transfer from the triplet state of porphyrins to the doublet state of the TTM radicals. The porphyrin-TTM pair shows a larger nuclear spin polarization under continuous laser excitation than the porphyrin-TEMPO pair because of the larger polarization and longer spin-lattice relaxation time of the TTM radical electron spins. This work demonstrates the first example of in-solution CIDEP and optically-driven DNP using TTM radicals, opening new opportunities in a wide range of biological and medical applications.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100181"},"PeriodicalIF":2.624,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.jmro.2024.100180
Shushu Gao , Jiamin Yuan , Fangxiu Ye , Zhiqiang Liu , Anming Zheng , Shutao Xu
Molecular sieves possess unique properties and have emerged as the predominant catalysts with shape selectivity in the petrochemical industry because of their well-defined pore architectures. However, the existence of a constrained pore surroundings of molecular sieves can limit intracrystalline diffusion, leading to underutilization of the active volume of the molecular sieve or rapid catalysts deactivation during catalytic processes. Moreover, the mechanism of adsorption and diffusion of molecules inside molecular sieves is crucial for the optimization and advancement of catalysts in heterogeneous catalysis. Due to the complexity of the diffusion process in molecular sieve materials, it is very necessary to develop characterization methods that are more sensitive and informative for studying the adsorption and diffusion of guests inside pores. Advancements in characterization techniques and theoretical calculations have led to a more profound comprehension of the adsorption and diffusion properties of molecular sieves at the microscopic scale. This article mainly summarizes the research progress of molecular adsorption and diffusion in molecular sieve materials using advanced 129Xe NMR, hyperpolarized (HP) 129Xe NMR, and pulsed-field gradient (PFG) NMR techniques in recent years and focuses on the principles of these techniques and applicability of the relationship of adsorption-diffusion using these techniques within several molecular sieve systems. Moreover, the effects of the topology and pore connectivity of molecular sieves on the adsorption and diffusion of guest molecules as well as the effects of intracrystalline diffusion on catalytic reactions are discussed.
{"title":"Applications of 129Xe and PFG NMR techniques on adsorption and diffusion of molecular sieve materials","authors":"Shushu Gao , Jiamin Yuan , Fangxiu Ye , Zhiqiang Liu , Anming Zheng , Shutao Xu","doi":"10.1016/j.jmro.2024.100180","DOIUrl":"10.1016/j.jmro.2024.100180","url":null,"abstract":"<div><div>Molecular sieves possess unique properties and have emerged as the predominant catalysts with shape selectivity in the petrochemical industry because of their well-defined pore architectures. However, the existence of a constrained pore surroundings of molecular sieves can limit intracrystalline diffusion, leading to underutilization of the active volume of the molecular sieve or rapid catalysts deactivation during catalytic processes. Moreover, the mechanism of adsorption and diffusion of molecules inside molecular sieves is crucial for the optimization and advancement of catalysts in heterogeneous catalysis. Due to the complexity of the diffusion process in molecular sieve materials, it is very necessary to develop characterization methods that are more sensitive and informative for studying the adsorption and diffusion of guests inside pores. Advancements in characterization techniques and theoretical calculations have led to a more profound comprehension of the adsorption and diffusion properties of molecular sieves at the microscopic scale. This article mainly summarizes the research progress of molecular adsorption and diffusion in molecular sieve materials using advanced <sup>129</sup>Xe NMR, hyperpolarized (HP) <sup>129</sup>Xe NMR, and pulsed-field gradient (PFG) NMR techniques in recent years and focuses on the principles of these techniques and applicability of the relationship of adsorption-diffusion using these techniques within several molecular sieve systems. Moreover, the effects of the topology and pore connectivity of molecular sieves on the adsorption and diffusion of guest molecules as well as the effects of intracrystalline diffusion on catalytic reactions are discussed.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100180"},"PeriodicalIF":2.624,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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