Journal of Magnetic Resonance Open最新文献

{"title":"Dynamic electron and nuclear spin polarization in solution using porphyrin and tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivatives","authors":"Reiya Yabuki ,&nbsp;Koki Nishimura ,&nbsp;Yuta Sawada ,&nbsp;Masaaki Fuki ,&nbsp;Yasuhiro Kobori ,&nbsp;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":"2025-03-01","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}

{"title":"Unveiling the impact of second-order 1H-17O Quadrupolar-Dipolar interaction on solid-state NMR spectroscopy","authors":"Yi Ji ,&nbsp;Kuizhi Chen ,&nbsp;Aijing Hao ,&nbsp;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 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}-<em>J</em>-heteronuclear multiple quantum coherence (HMQC), ¹H{¹⁷O}-<em>D</em>-HMQC, and ¹H→¹⁷O-<span><em>D</em></span>-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.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100182"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","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}

{"title":"Developing hyperpolarized metabolic contrast agents at high field dDNP for large animal research","authors":"Ditte B. Christensen ,&nbsp;Ingeborg S. Skre ,&nbsp;Jan Henrik Ardenkjær-Larsen,&nbsp;Magnus Karlsson,&nbsp;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, 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.</div><div>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.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100184"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","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}

{"title":"Hyperpolarized 129Xe for benchtop NMR: Inline instrumentation for automated yet flexible operation yielding high polarization","authors":"Wolfgang Kilian ,&nbsp;Samira Gulich ,&nbsp;Thomas Riemer ,&nbsp;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 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.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100179"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","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}

{"title":"Assessing a hyperpolarized [1-13C]-labeled alanine derivative enhanced via parahydrogen for in vivo studies","authors":"Lisa M. Fries ,&nbsp;Denis Moll ,&nbsp;Ruhuai Mei ,&nbsp;Theresa L․ K․ Hune ,&nbsp;Josef Elsaßer ,&nbsp;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":"2025-03-01","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}

{"title":"23Na intermolecular multiple-quantum coherences in salt solutions","authors":"Haoyu Li ,&nbsp;Yifan Song ,&nbsp;Yu Yin ,&nbsp;Juntao Xia ,&nbsp;Yun Chen ,&nbsp;Maria Grazia Concilio ,&nbsp;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 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.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100186"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","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}

{"title":"DNA Binding Mechanism of The Virulence Regulator SarA in Staphylococcus aureus","authors":"Dihong Fu ,&nbsp;Xiaoyun Guo ,&nbsp;Bo Duan ,&nbsp;Bin Xia","doi":"10.1016/j.jmro.2025.100188","DOIUrl":"10.1016/j.jmro.2025.100188","url":null,"abstract":"<div><div><em>Staphylococcus aureus</em> infections have long been a significant challenge to public health, particularly due to the emergence of multiple drug-resistant strains. SarA is a critical global regulator in <em>S. aureus</em> which binds to AT-rich sequences in the promoter regions of various genes, but the DNA-binding mechanism of SarA remains unclear. Here, we determined the solution structures of a monomeric DNA binding domain of SarA (SarA^ΔN19) and its complex with an AT-rich double-stranded DNA. The winged helix domain of SarA^ΔN19 binds to DNA in a classic way, with the α4 helix binding to the major groove of DNA, while the L5 loop binding to the minor groove, covering 10 AT base pairs. Residues L53, P65, and V68 of the α4 helix have hydrophobic interactions with thymine bases and sugar rings. The side chains of Arg90 and Arg84 from the wing are inserted into the minor groove, forming hydrogen bonds with A/T bases. Multiple positively charged or hydrophilic residues, including Lys54, Lys63, Lys69, Lys72, Lys82, and Gln64, interact with the phosphate groups on the DNA backbones. This complex structure provides an in-depth understanding of the molecular mechanism for SarA to bind DNA, and a better structure basis for future anti-bacterial drug design targeting SarA.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100188"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422621","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}

{"title":"Tribute to Alexander Pines (1945-2024)","authors":"Lucio Frydman ,&nbsp;Jeffrey A. Reimer","doi":"10.1016/j.jmro.2025.100185","DOIUrl":"10.1016/j.jmro.2025.100185","url":null,"abstract":"","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100185"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520486","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}

{"title":"Improved 2D hydride detection for NMR-chemosensing via p‐H2 Hyperpolarization","authors":"Ruud L.E.G. Aspers,&nbsp;Marco Tessari","doi":"10.1016/j.jmro.2024.100170","DOIUrl":"10.1016/j.jmro.2024.100170","url":null,"abstract":"<div><div>2D NMR zero-quantum spectroscopy offers a robust and convenient way to resolve hydride resonances in non-hydrogenative ParaHydrogen Induced Polarization experiments. This approach has been recently applied to the detection and quantification of dilute components in biofluids and natural extracts. For certain classes of analytes, however, modulation of the zero-quantum coherence occurs at several kiloHertz frequency, which determines long measurement times for attaining the desired resolution in the indirect dimension. Here, we propose an alternative 2D approach to measure high-resolution NMR spectra that affords enhanced sensitivity and reduced experimental time for optimal sample throughput.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100170"},"PeriodicalIF":2.624,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653621","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}

{"title":"MQMAS spectra of half-integer quadrupolar nuclei enhanced by indirect DNP","authors":"Hiroki Nagashima ,&nbsp;Julien Trébosc ,&nbsp;Olivier Lafon ,&nbsp;Jean-Paul Amoureux","doi":"10.1016/j.jmro.2024.100177","DOIUrl":"10.1016/j.jmro.2024.100177","url":null,"abstract":"<div><div>The observation of half-integer quadrupolar nuclei, which represent 66 % of the NMR-active isotopes, is essential to understand the atomic-level structure of inorganic materials near the surfaces with applications in the field of catalysis, biomaterials and optoelectronics. For that purpose, we have recently introduced an efficient technique, which combines the sensitivity gain provided by indirect DNP (dynamic nuclear polarization) under MAS (magic-angle spinning) and the high resolution obtained by refocusing the second-order quadrupolar interaction (H. Nagashima et al.<em>, J. Phys. Chem. Lett.</em> 15 (2024) 4858). This technique combines (i) a <em>D</em>-RINEPT (dipolar-mediated refocused INEPT) transfer, (ii) an MQMAS (multiple-quantum MAS) filter, and (iii) a QCPMG (quadrupolar Carr-Purcell Meiboom-Gill) detection. We explain the design of several variants of this pulse sequence and notably the selection of the coherence transfer pathways. In particular, the amplitudes of the coherence transfer pathways through the ±3Q coherence orders of the quadrupolar isotope can be equalized using a train of π-pulses selective of the central transition, instead of a z-filter. This equalization method has the advantage to limit the length of the phase cycles and to enhance slightly the signal intensity. Moreover, for spin-3/2 nuclei subject to moderate or large quadrupolar interactions, more efficient excitation and conversion of 3Q coherences are achieved using cosine-modulated long-pulses (cos-lp), instead of fast-amplitude-modulated (FAM) pulses. The performances of the different <em>D</em>-RINEPT-MQMAS-QCPMG variants are compared through the observation of ³⁵Cl and ²⁷Al isotopes without DNP in <span>l</span>-histidine hydrochloride and isopropylamine-templated microporous aluminophosphate (ipa-AlPO₄–14), respectively, as well as the acquisition of DNP-enhanced high-resolution spectra of ¹¹B and ¹⁷O nuclei near the surface of partially oxidized boron nitride supported on dendritic and fibrous nanosilica and γ-alumina enriched in ¹⁷O isotope using a slurrying approach. The spectra recorded for γ-alumina show that the slurrying method produces less disorder than grinding assisted by ¹⁷O-enriched water.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100177"},"PeriodicalIF":2.624,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722642","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}