Journal of Magnetic Resonance Open最新文献

{"title":"Paramagnetic relaxation: Direct and Raman relaxation of spin S=12","authors":"W.Th. Wenckebach","doi":"10.1016/j.jmro.2025.100193","DOIUrl":"10.1016/j.jmro.2025.100193","url":null,"abstract":"<div><div>Paramagnetic relaxation in solids is a vast subject, about as vast as the range of manifestations of electron spin in matter. It is a complex subject as well: it is the interface between paramagnetic centres – be it transition metal ions, radicals or defects – and quantized vibrations: phonons. So it requires an understanding of both these phonons and those paramagnetic centres. Moreover, contrary to the case of integer spin, for half-integer spin the coupling between electron spins and phonons is indirect. Two interactions are needed, the spin–orbit interaction between the spin and the orbits of the paramagnetic centre and the orbit–phonon interaction between the latter and the phonons.</div><div>The present article is an effort to navigate the theory of this extensive subject for spin <span><math><mrow><mi>S</mi><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span> and aims to derive the main properties of the two most important mechanisms: direct and red Raman relaxation. It tries to do so from first principles, that is, it includes a generalized, but fundamental description of the vibrational states, the orbital and spin states on the one hand, and the orbit–phonon and spin–orbit interaction on the other. Based on these descriptions it derives the transition matrix elements responsible for paramagnetic relaxation, following the original approach of Van Vleck for paramagnetic centres with spin <span><math><mrow><mi>S</mi><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span>, a relatively weak spin–orbit interaction and embedded in an insulating, diamagnetic solid. Subsequently phonon statistics are included to derive the paramagnetic relaxation rates. No effort is done to review the vast body of experimental work on the subject.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100193"},"PeriodicalIF":2.624,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637503","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":"Ultrafast 2D benchtop NMR spectroscopy enhanced by flow Overhauser dynamic nuclear polarization","authors":"Joris Mandral ,&nbsp;Johnnie Phuong ,&nbsp;Jonathan Farjon ,&nbsp;Patrick Giraudeau ,&nbsp;Kerstin Münnemann ,&nbsp;Jean-Nicolas Dumez","doi":"10.1016/j.jmro.2025.100195","DOIUrl":"10.1016/j.jmro.2025.100195","url":null,"abstract":"<div><div>Benchtop Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical technique for the monitoring of reactions and processes due to its accessibility and lower cost compared to high-field NMR. However, benchtop NMR spectroscopy often suffers from limited sensitivity and resolution. In this work, we have combined ultrafast (UF) 2D NMR with Overhauser Dynamic Nuclear Polarization (ODNP) to tackle both problems. Compared to thermally polarized 1D NMR, UF 2D NMR provides improved spectral resolution in a single scan whereas ODNP boosts the NMR sensitivity. To demonstrate the possibility of combining UF 2D NMR with ODNP for process monitoring applications, experiments were carried out at different flow conditions. Our results show that ODNP at least compensated for the losses in sensitivity of UF 2D NMR that are normally induced by high flow velocities. Moreover, under certain flow conditions, ODNP brings additional sensitivity to UF 2D NMR spectra, with SNR increased by a factor of &gt;3 compared to thermal equilibrium acquisitions. The methods developed in this article are expected to be beneficial for more informative and sensitive acquisitions in the context of process monitoring.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100195"},"PeriodicalIF":2.624,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641918","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":"Probing nanoparticle proximity effects on selective butadiene hydrogenation over Pd-Au/TiO2 with parahydrogen-induced polarization NMR","authors":"Bintian Lu ,&nbsp;Weiyu Wang ,&nbsp;Shuangqin Zeng ,&nbsp;Xiuzhi Gao ,&nbsp;Jun Xu ,&nbsp;Feng Deng","doi":"10.1016/j.jmro.2025.100192","DOIUrl":"10.1016/j.jmro.2025.100192","url":null,"abstract":"<div><div>Selective butadiene hydrogenation to butene is a crucial process in the petrochemical industry, however, a comprehensive understanding of the underlying structure-activity relationships remains elusive. This study explores the influence of supported metal nanoparticle proximity on butadiene hydrogenation using parahydrogen-induced polarization NMR spectroscopy. A sol-immobilization method was employed to systematically control the spacing between PdAu nanoparticles on Pd-Au/TiO₂ catalysts, while preserving their overall physicochemical properties. Experimental results demonstrate that denser PdAu nanoparticle arrangements lead to enhanced catalytic activity. This improved activity is coupled with accelerated isomerization of the semi-hydrogenated butene and over-hydrogenation to butane, facilitated by enhanced butene adsorption and subsequent conversion. Furthermore, increasing the hydrogen content significantly boosts butadiene conversion and butane formation, while having a less impact on butene isomerization. The addition of an inert support material, altering the spatial distribution of catalyst particles, positively affects both catalytic activity and butene selectivity. These findings highlight the critical role of nanoparticle proximity in controlling reaction pathways in butadiene hydrogenation.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100192"},"PeriodicalIF":2.624,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577291","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":"Robotic arms for hyperpolarization-enhanced NMR","authors":"Kirill Sheberstov ,&nbsp;Erik Van Dyke ,&nbsp;Jingyan Xu ,&nbsp;Raphael Kircher ,&nbsp;Liubov Chuchkova ,&nbsp;Yinan Hu ,&nbsp;Sulaiman Alvi ,&nbsp;Dmitry Budker ,&nbsp;Danila A. Barskiy","doi":"10.1016/j.jmro.2025.100194","DOIUrl":"10.1016/j.jmro.2025.100194","url":null,"abstract":"<div><div>Optimization of nuclear spin hyperpolarization experiments often require varying one system parameter at a time (or several parameters in a nontrivial manner) as well as multiple repetitions of signal measurements. Use of automated robotic systems can significantly streamline this optimization process, accelerating data acquisition and improving reproducibility in the long term. In this work we show an exemplary system built on open-source components and demonstrate several benchtop and ultralow-field NMR experiments employing photo-CIDNP and SABRE-derived hyperpolarization. This work illustrates that open-source platforms employing benchtop NMR and robotic systems built in a modular manner with remote operation allow the implementation of various unconventional experiments in a reproducible manner.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100194"},"PeriodicalIF":2.624,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577292","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":"Introduction to average Hamiltonian theory. II. Advanced examples","authors":"Andreas Brinkmann","doi":"10.1016/j.jmro.2025.100191","DOIUrl":"10.1016/j.jmro.2025.100191","url":null,"abstract":"<div><div>Where the first part of our tutorial <em>Introduction to average Hamiltonian theory</em> (Brinkmann, 2016) introduced in detail the basic concepts and demonstrated the application to two composite radio-frequency (rf) pulses in nuclear magnetic resonance (NMR) spectroscopy, this second part will present in a comprehensive but educational manner two, more advanced examples for the application of average Hamiltonian theory in solid-state NMR spectroscopy, both to analyse and design rf pulse sequences: (i) The Rotational-Echo Double Resonance (REDOR) sequence, which recouples the heteronuclear dipolar coupling during sample rotation around an axis at the magic-angle of <span><math><mrow><mn>54</mn><mo>.</mo><mn>7</mn><msup><mrow><mn>4</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> with respect to the external static magnetic field. We will gradually increase the complexity of applying average Hamiltonian theory by first considering ideal, infinitesimally short rf pulses. Next, we will examine finite pulses with an rf phase of zero, and finally, we will explore finite pulses with arbitrary rf phases. In the latter case, if a first order average Hamiltonian proportional to heteronuclear longitudinal two-spin order (<span><math><mrow><mn>2</mn><msub><mrow><mi>I</mi></mrow><mrow><mi>z</mi></mrow></msub><msub><mrow><mi>S</mi></mrow><mrow><mi>z</mi></mrow></msub></mrow></math></span>) is desired, solutions for the choice of rf phases include the XY and MLEV type schemes. (ii) The Lee–Goldburg homonuclear dipolar decoupling sequence under static samples conditions and its improved successors, Flip-Flop Lee–Goldburg (FFLG) and Frequency-Switched Lee–Goldburg (FSLG).</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100191"},"PeriodicalIF":2.624,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474023","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":"2025-02-10","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":"Chiral recognition of some D and L-amino acids by microcrystalline cellulose assisted diffusion-ordered NMR spectroscopy","authors":"Bowen Han ,&nbsp;Jing He ,&nbsp;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}

{"title":"A hybrid setup for rodent hyperpolarized metabolic imaging using a clinical magnetic resonance scanner","authors":"Ditte Bentsen Christensen ,&nbsp;Ingeborg Sæten Skre ,&nbsp;Jan Henrik Ardenkjær-Larsen ,&nbsp;Mor Mishkovsky ,&nbsp;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 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.</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}

{"title":"Evaluating metrics of spectral quality in nonuniform sampling","authors":"D. Levi Love,&nbsp;Michael R. Gryk,&nbsp;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}