Magnetic Resonance Letters最新文献

{"title":"Heptanuclear iron complex as a potential contrast agent for MRI","authors":"Ekaterina E. Batueva,&nbsp;Alsu R. Sharipova,&nbsp;Olga A. Turanova,&nbsp;Alexander E. Klimovitskii,&nbsp;Alexander N. Turanov","doi":"10.1016/j.mrl.2025.200256","DOIUrl":"10.1016/j.mrl.2025.200256","url":null,"abstract":"<div><div>A heptanuclear complex of the composition [Fe(II)(CN)₆{Fe(III)](L)}₆](SCN)₂, where L = dianion N,N-bis(1-hydroxy-2-benzylidene)-1,7-diamino-4-azageptane has been studied as a potential contrast agent for magnetic resonance imaging. The longitudinal and transverse relaxation times of water in a colloidal solution of this molecular magnet with sodium dodecyl sulfate were measured by ¹H nuclear magnetic resonance spectroscopy, depending on the concentration, and its relaxivity was calculated. The obtained relaxation values indicate that this complex is a promising candidate for use as a contrast agent in magnetic resonance imaging. This preliminary study is aimed at identifying the possibility of applying the heptanuclear complex as a magnetic resonance imaging contrast agent.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200256"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398283/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586206","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":"NMR spectral simplification with imidazolium ionic liquid-coated silica nanoparticles","authors":"Ying Yang,&nbsp;Biling Huang,&nbsp;Qiong Wang,&nbsp;Guangjin Hou,&nbsp;Shaohua Huang","doi":"10.1016/j.mrl.2026.200259","DOIUrl":"10.1016/j.mrl.2026.200259","url":null,"abstract":"<div><div>NMR spectral simplification is a powerful strategy for facilitating the analysis and structural characterization of complex mixtures. In this work, we present a nanoparticle-assisted protocol that employs positively charged imidazolium ionic liquid-coated silica nanoparticles (<strong><em>1</em></strong>) to selectively interact with analytes. π-π interactions, electrostatic attractions, and hydrogen-bonding between the nanoparticles and target molecules extend the rotational correlation time, thereby accelerating relaxation processes. As a result, NMR signals from aromatic and negatively charged species undergo pronounced attenuation or even complete disappearance. In contrast, signals from positively charged analytes or compounds lacking π-bond systems remain largely unaffected. This selective suppression of resonances enables effective spectral simplification and highlights the potential of nanoparticle-based editing approaches for practical applications in the analysis and structural determination of complex mixtures.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200259"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147884041","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":"OFC: Outside Front Cover","authors":"","doi":"10.1016/S2772-5162(26)00040-9","DOIUrl":"10.1016/S2772-5162(26)00040-9","url":null,"abstract":"","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200296"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148635332","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":"Fast three-dimensional NMR spectroscopy reconstruction based on Hankel matrix with two-directional sliding windows","authors":"Tianyu Qiu,&nbsp;Hao Fu,&nbsp;Xiaobo Qu,&nbsp;Di Guo","doi":"10.1016/j.mrl.2025.200254","DOIUrl":"10.1016/j.mrl.2025.200254","url":null,"abstract":"<div><div>Nuclear magnetic resonance (NMR) spectroscopy has grown into a formidable tool in biomedical analysis and quantification. However, the lengthy acquisition for high-dimensional NMR spectroscopy hinders its broader applications. Non-uniform sampling (NUS) effectively reduces the acquisition time by acquiring partial data. Therefore, the need for reconstruction methods is motivated. The low-rank block Hankel matrix reconstruction method achieves notable reconstruction, but requiring prolonged computational time. In this work, a novel two-directional sliding window method is proposed to reduce the size of the low-rank matrix, effectively mitigating the computational time. Incorporating the parallel computation, further acceleration can be achieved. The numerical experiments on synthetic and real NMR spectroscopy illustrate that, among compared approaches, the proposed method accomplishes reconstruction in the shortest time without compromising the spectral quality.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200254"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398272/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586166","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":"Impact of mutual and environmental dipole-dipole interactions on the relaxation of MQ NMR coherences in two-spin system in course of their excitation and reconversion","authors":"Georgii A. Bochkin,&nbsp;Edward B. Fel'dman,&nbsp;Elena I. Kuznetsova,&nbsp;Sergey G. Vasil'ev,&nbsp;Alexander I. Zenchuk","doi":"10.1016/j.mrl.2026.200258","DOIUrl":"10.1016/j.mrl.2026.200258","url":null,"abstract":"<div><div>The relaxation of multiple-quantum (MQ) NMR coherences on the excitation and reconversion periods of MQ NMR experiment was investigated for the spin-pairs coupled by dipole-dipole interaction. The ¹H spin-pairs were obtained in the single crystal of hambergite at specific orientations in the external magnetic field. The planar zigzag arrangement of the protons in hambergite allows obtaining two situations with different strengths of interaction between spins in a pair and remote surrounding spins. The obtained experimental results show good agreement with the developed theory based on the Lindblad equation.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200258"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398281/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586155","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":"Chemical exchange saturation transfer NMR: An analytical tool and its applications","authors":"Lixia Wang,&nbsp;Jie Cui,&nbsp;Junfeng Xiang","doi":"10.1016/j.mrl.2025.200255","DOIUrl":"10.1016/j.mrl.2025.200255","url":null,"abstract":"<div><div>NMR spectroscopy has proven to be a powerful tool for elucidating structural information and studying dynamic processes. Among NMR techniques, chemical exchange saturation transfer (CEST) is particularly suitable for investigating systems with slow exchange rates and holds significant promise for tracking metastable intermediates to explore dynamic mechanisms. This review focuses on applications of CEST in chemistry, including: (1) detection of transient species in living systems, (2) kinetic characterization of chemical reactions and conformational changes, and (3) selective recognition facilitated by paramagnetic reagents. The CEST methodology thus offers novel approaches for organic chemists and chemical biologists, while providing insights into dynamic kinetics across diverse research fields.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 3","pages":"Article 200255"},"PeriodicalIF":1.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398279/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586210","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":"FlexCENT: A frequency-flexible CEST imaging network combining frequency offset encoding and three-dimensional U-Net","authors":"Jingyi Yu ,&nbsp;Mengying Zhu ,&nbsp;Yonggui Yang ,&nbsp;Congbo Cai ,&nbsp;Shuhui Cai","doi":"10.1016/j.mrl.2025.200240","DOIUrl":"10.1016/j.mrl.2025.200240","url":null,"abstract":"<div><div>This study proposes a deep learning-based method termed frequency-flexible chemical exchange saturation transfer (CEST) imaging network (FlexCENT), which enables robust CEST quantification across variable frequency offset schemes without requiring retraining. FlexCENT integrates frequency offset encoding with a three-dimensional (3D) U-Net to process CEST images and frequency offsets as inputs and predict Lorentzian parameters of the 4-pool model (water, MT, APT, rNOE), including <em>B</em>₀ inhomogeneity. By transforming frequency offsets into a continuous spectral feature representation, the frequency offset encoding allows FlexCENT to generalize to unseen frequency offset schemes. Trained on synthetic data generated from the 4-pool Lorentzian model, FlexCENT was validated through numerical simulations, tumor-bearing mouse experiments, and a human brain experiment, alongside comparisons with 4-pool Lorentzian fitting, DeepCEST, and LKAN networks. The results demonstrate that FlexCENT successfully quantified CEST parameters across all experiments, maintaining consistent performance under varying frequency offset conditions without retraining. It exhibited superior noise robustness in numerical simulations and enhanced anatomical delineation <em>in vivo</em> parametric mapping compared to other methods. In conclusion, by combining spectral information with spatial information, FlexCENT provides an efficient, flexible, and robust quantitative approach for CEST imaging. It significantly enhance the quantification capability and clinical potential of CEST imaging.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 2","pages":"Article 200240"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Passive water exchange between multiple sites can explain why apparent exchange rate constants depend on ionic and osmotic conditions in gray matter","authors":"Nathan H. Williamson ,&nbsp;Rea Ravin ,&nbsp;Teddy X. Cai ,&nbsp;Julian A. Rey ,&nbsp;Peter J. Basser","doi":"10.1016/j.mrl.2025.200225","DOIUrl":"10.1016/j.mrl.2025.200225","url":null,"abstract":"<div><div>Porous materials, such as biological tissue, often have heterogeneous microstructures where imbibed fluid experiences distinct environments on short timescales, but can exchange among different environments over long timescales. Nuclear magnetic resonance (NMR) methods such as diffusion exchange spectroscopy (DEXSY) can measure this exchange in water under steady-state and equilibrium conditions; however, modeling becomes more complex when more than two exchanging environments are involved. This complexity is particularly relevant in the central nervous system (CNS), where water diffusion and exchange at the cellular level play critical roles in homeostasis. While DEXSY can measure these processes, they may not be adequately modeled as two-site exchange between intracellular and extracellular spaces (ICS and ECS). Here we study the behavior of apparent exchange rate constants (AXR) estimated from DEXSY data numerically simulated using a three-site exchange model (3XM). The 3XM is based on gray matter microstructural characteristics, incorporating both transmembrane exchange between ECS and ICS and geometric exchange between environments within ICS where water mobility differs due to the complex architecture of neurons, glial cells, and the ECS. Inspired by the Na⁺/K⁺–ATPase pump–leak model of cell volume maintenance, the 3XM accounts for effects of osmolytes, ions, and voltage on ECS and ICS volume fraction. The model predicts a significant reduction in AXR and a smaller decrease in apparent diffusion coefficients (ADC) following the level of membrane depolarization expected from Na⁺/K⁺–ATPase inhibition. These changes were reversed by the addition of membrane-impermeable ECS osmolytes, independent of voltage, in agreement with previous experiments. While the exchange rate constants for each pathway simply follow first-order kinetics, the AXR's sensitivity to these pathways depends on the ECS volume fraction. When ECS is present, transmembrane exchange dominates, but when cells swell following pump inhibition, geometric exchange becomes the dominant pathway.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 2","pages":"Article 200225"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fragment-based discovery of TopBP1 inhibitors integrated with AI-driven molecular docking","authors":"Wenlong Chen ,&nbsp;Song Zhang ,&nbsp;Zihuan Li ,&nbsp;Lei Wang ,&nbsp;Jiahai Zhang ,&nbsp;Jia Gao ,&nbsp;Ke Ruan","doi":"10.1016/j.mrl.2025.200251","DOIUrl":"10.1016/j.mrl.2025.200251","url":null,"abstract":"<div><div>DNA topoisomerase IIβ-binding protein 1 (TopBP1) converges on multiple oncogenic pathways, e.g., Rb, p53, and PI3K/Akt, which are hallmarks of most cancer progression. However, the lack of structural studies makes the underlying mechanism of action of TopBP1 inhibitors promiscuous.</div><div>Herein, we employ a fragment-based screening approach to identify four small-molecule ligands against the TopBP1 BRCT7-8 domain: adamantane acetic acid (ADA), zaltoprofen, diclofenac sodium, and quinine. The dissociation constants of these compounds are determined by nuclear magnetic resonance (NMR) chemical shift perturbations, which suggests the former three hits bind to the same site, while quinine binds to a distinct site. The binding models of these four hits are further predicted by the deep learning model Chai-1. The complex crystal structure of the TopBP1 BRCT7-8 domain demonstrates ADA as an orthosteric inhibitor of TopBP1, as further validated by its binding to TopBP1 in competition with the native substrate BACH1. Our NMR screening nominates orthosteric inhibitors, as well as quinine, a potential allosteric inhibitor. It shall also facilitate following structure-based design of more potent allosteric and orthosteric inhibitors of TopBP1.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 2","pages":"Article 200251"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147884322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OFC: Outside Front Cover","authors":"","doi":"10.1016/S2772-5162(26)00021-5","DOIUrl":"10.1016/S2772-5162(26)00021-5","url":null,"abstract":"","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"6 2","pages":"Article 200277"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}