Magnetic Resonance Letters最新文献

{"title":"Unexpected temperature dependence of 1H paramagnetic shift in MAS NMR of nickelocene","authors":"Xinbiao Jiang,&nbsp;Jiefan Liu,&nbsp;Xiaobing Lou,&nbsp;Bingwen Hu,&nbsp;Ming Shen","doi":"10.1016/j.mrl.2024.200119","DOIUrl":"10.1016/j.mrl.2024.200119","url":null,"abstract":"<div><div>This work revisits the temperature dependence of ¹H paramagnetic shift in nickelocene as a potential nuclear magnetic resonance (NMR) thermometer under fast magic angle spinning (MAS) rate. Surprisingly, an abnormal temperature dependence of ¹H paramagnetic shift has been observed. In addition to a 1/<em>T</em> dependence term, a 1/<em>T</em>² dependence term must be included to correctly describe the curvature behavior of the <em>δ</em>^₁_H-<em>T</em> correlation under fast MAS rate.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200119"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140401608","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":"Enantiodifferentiation of chiral diols and diphenols via recognition-enabled chromatographic 19F NMR","authors":"Yilin Zeng ,&nbsp;Wenjing Bao ,&nbsp;Guangxing Gu ,&nbsp;Yanchuan Zhao","doi":"10.1016/j.mrl.2024.200112","DOIUrl":"10.1016/j.mrl.2024.200112","url":null,"abstract":"<div><div>A novel and efficient method for distinguishing between chiral diols and diphenols has been established through the use of ¹⁹F NMR spectroscopy. Central to this system's efficacy is a chiral amine, strategically modified with a CF₃ group. This amine reacts <em>in-situ</em> with 2-formylphenylboronic acid to create a chiral ¹⁹F-labeled probe. This probe demonstrates discriminatory capabilities by interacting with hydroxy-containing analytes to form boronic esters. These esters produce distinct ¹⁹F NMR signals that vary according to their stereoconfiguration, facilitating accurate chiral differentiation. The method's resolution capacity was demonstrated by successfully identifying 12 distinct chiral analytes (six pairs of enantiomers) in complex mixtures, highlighting its extensive potential in diverse chiral analysis applications.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200112"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139829624","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":"Diffusion tractography of kidney by high angular resolution diffusion imaging","authors":"Surendra Maharjan ,&nbsp;Jie Chen ,&nbsp;Adrienne Gaughan ,&nbsp;Neal X. Chen ,&nbsp;Nian Wang","doi":"10.1016/j.mrl.2024.200117","DOIUrl":"10.1016/j.mrl.2024.200117","url":null,"abstract":"<div><div>Diffusion magnetic resonance imaging (MRI) has been utilized to probe the renal microstructures but investigating the three-dimensional (3D) tubular network still presents significant challenges due to the complicated architecture of kidney. This study aims to assess whether high angular resolution diffusion imaging (HARDI) could improve the reconstruction of 3D tubular architectures. Kidneys from both mice and rats were imaged using 3D diffusion-weighted pulse sequences at 9.4 T. Five healthy mouse kidneys were scanned at an isotropic spatial resolution of 40 μm, with a <em>b</em> value of 1500 s/mm² across 46 diffusion encoding directions. The study employed diffusion tensor imaging (DTI) and generalized Q-sampling imaging (GQI) to examine the tubular orientation distributions and tractography, validated by conventional histology. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified and compared among the inner medullar (IM), outer medullar (OM), and cortex (CO) at different angular resolutions. FA values, estimated with 6 diffusion-weighted images (DWIs), were significantly overestimated by 49.9% (<em>p</em> &lt; 0.001) in IM, 179.4% (<em>p</em> &lt; 0.001) in OM, and 225.5% (<em>p</em> &lt; 0.001) in CO, compared to using 46 DWIs. In contrast, MD exhibited less variations to angular resolution variations (3.4% in IM, 4.2% in OM, and 4.6% in CO). Both DTI and GQI at high angular resolution successfully traced renal tubular structures throughout the kidney, with GQI demonstrating superior performance in generating more continuous tracts. Furthermore, disrupted renal tubule structures were observed in a chronic kidney disease (CKD) rat model. HARDI, especially when combined with the GQI approach, holds promise in tracking complicated 3D tubule architectures and may serve as a potent tool for kidney disease research.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200117"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140405734","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 T1 mapping MRI in preclinical and clinical settings using subspace-constrained joint-domain reconstructions","authors":"Lingceng Ma ,&nbsp;Qingjia Bao ,&nbsp;Ricardo P. Martinho ,&nbsp;Zhong Chen ,&nbsp;Lucio Frydman","doi":"10.1016/j.mrl.2024.200134","DOIUrl":"10.1016/j.mrl.2024.200134","url":null,"abstract":"<div><div>This work aims to develop fast <em>T</em>₁ mapping methods for preclinical and clinical scanners based on subspace-constrained reconstructions. Two sequences are explored for rapid <em>T</em>₁ characterizations: 1) Interleaved spatiotemporal encoding incorporating variable repetition times. 2) Inversion recovery gradient echo with random sampling of the phase-encoding (PE) dimension. For both sequences, the subspace reconstruction of the signal recovery was applied, to jointly reconstruct the down-sampled images while characterizing the <em>T</em>₁ relaxation. <em>In vivo</em> scans on human brains and abdomens confirmed the efficiency of the proposed methods, including compatibility with breath-holding. In addition, Scans on animals with abdominal tumors and dynamic contrast-enhanced <em>T</em>₁ mapping on kidneys support the applicability of the proposed methods also in preclinical settings.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200134"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722466","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 structural and dynamical features of chromatin using NMR spectroscopy","authors":"Xiangyan Shi","doi":"10.1016/j.mrl.2024.200153","DOIUrl":"10.1016/j.mrl.2024.200153","url":null,"abstract":"<div><div>Eukaryotic deoxyribonucleic acid (DNA) is wrapped around histone octamers (HOs) to form nucleosome core particles (NCPs), which in turn interact with linker DNA and linker histones to assemble chromatin fibers with more complex, high-order structures. The molecular properties of chromatin are dynamically regulated by several factors, such as post-translational modifications and effector proteins, to maintain genome stability. In the past two decades, high-resolution techniques have led to many breakthroughs in understanding the molecular mechanisms that govern chromatin regulation. Nuclear magnetic resonance (NMR) has emerged as one of the major techniques in this field, providing new insights into the nucleosomes and nucleosome-protein complexes in different states ranging from soluble form to condensed states. Solution-state NMR has proven valuable in elucidating the conformational dynamics and molecular interactions for histone N-terminal tails, histone core regions and DNA with the combination of specific isotopic labeling. Solid-state NMR, which is not constrained by the high molecular weights of complexes like nucleosomes, has been applied to capture the structural and dynamical characteristics of both flexible tails and rigid histone core regions in nucleosomes and their complexes with effector proteins. Furthermore, the combination of the two techniques allows tracking molecular properties of nucleosomes during phase separation processes, which potentially play essential roles in chromatin regulation. This review summarizes recent advances in NMR studies of chromatin structure and dynamics. It highlighted that NMR revealed unique molecular characteristics for nucleosomes that are often invisible experimentally by other techniques like cryogenic electron microscopy (cryo-EM) and X-ray diffraction (XRD). I envision that, with future efforts such as the development of NMR methods and optimization of sample production protocols, solution-state NMR and solid-state NMR will provide invaluable information to expand our understanding of chromatin activity and its regulatory processes.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200153"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839040","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":"Solid-state NMR of vulcanized natural rubber/butadiene rubber blends: Local organization and cross-linking heterogeneities","authors":"Pierre Daniel ,&nbsp;Cristina Coelho-Diogo ,&nbsp;Valérie Gaucher ,&nbsp;Grégory Stoclet ,&nbsp;Clément Robin ,&nbsp;Cédric Lorthioir","doi":"10.1016/j.mrl.2024.200155","DOIUrl":"10.1016/j.mrl.2024.200155","url":null,"abstract":"<div><div>Elastomer blends, among which natural rubber (NR) and butadiene rubber (BR), are involved in many components of the automotive/tire industry. A comprehensive understanding of their mechanical behavior requires, among other features, a detailed description of the cross-link density in these mixtures. In the case of vulcanized immiscible blends, the distribution of the cross-link density within each of the NR- and BR-rich domains is key information, but difficult to determine using the conventional approaches used for one-component cross-linked elastomers. In this study, the vulcanization within NR/BR blends is investigated using a robust ¹H double-quantum (DQ) MAS recoupling experiment, BaBa-xy16. Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component. The bulk organization of the resulting blends was first probed by analyzing the ¹H spin-lattice relaxation behavior. In a second step, BaBa-xy16 was used to investigate, in a selective way, the cross-link heterogeneities within NR/BR blends. In particular, for immiscible NR/BR mixtures, the distribution of the cross-link density between both phases was compared and the observed differences were discussed.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200155"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722467","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":"Progress in magnetic resonance imaging of the glymphatic system","authors":"Jinhao Lyu ,&nbsp;Xinyu Wang ,&nbsp;Qi Duan,&nbsp;Wanbing Wang,&nbsp;Runze Li,&nbsp;Xiaoyu Wang,&nbsp;Xin Lou","doi":"10.1016/j.mrl.2024.200154","DOIUrl":"10.1016/j.mrl.2024.200154","url":null,"abstract":"<div><div>The glymphatic system (GS) is a newly discovered brain anatomy. Its discovery improves our understanding of brain fluid flow and waste removal paths and provides an anatomical basis for the flow of cerebral interstitial fluid (ISF) and cerebrospinal fluid (CSF). GS occurs through a normal exchange within perivascular space (PVS), facilitating the elimination of metabolic wastes generated by nerve cells from the brain. Therefore, the GS is mainly responsible for the removal of metabolic waste. Reduced GS activity has been observed to be associated with central nervous system disorders such as cerebral small vessel disease (CSVD) and neurodegenerative diseases. Its activity is expected to be an indicator for diagnosing diseases and predicting their prognosis. This review introduces the magnetic resonance imaging (MRI) technology related to the GS suitable for clinical use and the difference in the system's activity in normal and abnormal states. Through a summary of previous research, imaging methods suitable for monitoring the activity of the GS in the clinic were proposed, and their diagnostic effect on different brain disorders was analyzed. This review aims to clarify ideas for the clinical translation of basic research focusing on GS and provide future clinical research directions and perspectives.</div></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 4","pages":"Article 200154"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722465","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":"Analysis of the electron transfer pathway in small laccase by EPR and UV–vis spectroscopy coupled with redox titration","authors":"","doi":"10.1016/j.mrl.2024.200116","DOIUrl":"10.1016/j.mrl.2024.200116","url":null,"abstract":"<div><p>Bacterial small laccases (SLAC) are promising industrial biocatalysts due to their ability to oxidize a broad range of substrates with exceptional thermostability and tolerance for alkaline pH. Electron transfer between substrate, copper centers, and O₂ is one of the key steps in the catalytic turnover of SLAC. However, limited research has been conducted on the electron transfer pathway of SLAC and SLAC-catalyzed reactions, hindering further engineering of SLAC to produce tunable biocatalysts for novel applications. Herein, the combinational use of electron paramagnetic resonance (EPR) and ultraviolet–visible (UV–vis) spectroscopic methods coupled with redox titration were employed to monitor the electron transfer processes and obtain further insights into the electron transfer pathway in SLAC. The reduction potentials for type 1 copper (T1Cu), type 2 copper (T2Cu) and type 3 copper (T3Cu) were determined to be 367 ± 2 mV, 378 ± 5 mV and 403 ± 2 mV, respectively. Moreover, the reduction potential of a selected substrate of SLAC, hydroquinone (HQ), was determined to be 288 mV using cyclic voltammetry (CV). In this way, an electron transfer pathway was identified based on the reduction potentials. Specifically, electrons are transferred from HQ to T1Cu, then to T2Cu and T3Cu, and finally to O₂. Furthermore, superhyperfine splitting observed via EPR during redox titration indicated a modification in the covalency of T2Cu upon electron uptake, suggesting a conformational alteration in the protein environment surrounding the copper sites, which could potentially influence the reduction potential of the copper sites during catalytic processes. The results presented here not only provide a comprehensive method for analyzing the electron transfer pathway in metalloenzymes through reduction potential measurements, but also offer valuable insights for further engineering and directed evolution studies of SLAC in the aim for biotechnological and industrial applications.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 3","pages":"Article 200116"},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516224000238/pdfft?md5=9be3abce237719dfdcdc2795a0079a5f&pid=1-s2.0-S2772516224000238-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140272181","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":"Solid-state NMR studies of proteins in condensed phases","authors":"Jiani Xiang ,&nbsp;Xialian Wu ,&nbsp;Angelo L. Chu ,&nbsp;Junxia Lu","doi":"10.1016/j.mrl.2024.200140","DOIUrl":"10.1016/j.mrl.2024.200140","url":null,"abstract":"<div><p>Some proteins perform their biological functions by changing their material states through liquid-liquid phase separation. Upon phase separation, the protein condenses into a concentrated liquid phase and sometimes into a gel phase, changing its dynamic properties and intermolecular interactions, thereby regulating cellular functions. Although the biological significance of this phenomenon has been widely recognized by researchers, there is still a lack of a comprehensive understanding of the structural and dynamic properties of the protein in the condensed phase. In this phase, molecules usually contain domains with varied dynamic properties and undergo intermediate exchanges. Magic angle spinning (MAS) solid-state NMR (SSNMR) experiments are very powerful in studying rigid protein polymers such as amyloid. The incorporation of solution-like experiments into SSNMR and the development of <em>J</em>-coupling based MAS SSNMR techniques extend its ability to study partially mobile segments of proteins in a condensed liquid or gel phase which are not visible by solution NMR or dipolar-coupling based SSNMR. Therefore, it has been applied in studying protein condensation and has provided very important information that is hard to obtain by other techniques.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 3","pages":"Article 200140"},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516224000470/pdfft?md5=a6d1ccfcd310ca75a05a0dcce0fe732e&pid=1-s2.0-S2772516224000470-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142040942","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":"Facile identification of fluorosurfactant category in aqueous film-forming foam concentrates via optimized 19F NMR","authors":"","doi":"10.1016/j.mrl.2023.12.005","DOIUrl":"10.1016/j.mrl.2023.12.005","url":null,"abstract":"<div><p>Aqueous film-forming foams (AFFFs) are the primary source of toxic perfluoroalkyl and polyfluoroalkyl substances (PFAS) in wastewater. Thus, it is urgent to develop a facile and fast method for identifying fluorosurfactants in commercially available AFFFs. In this work, fluorine nuclear magnetic resonance (¹⁹F NMR) spectroscopy was optimized to measure AFFFs directly with the extra addition of 5% D₂O as the locking reagent, and high-quality spectra could be acquired within 4 min (0.1% fluorosurfactant content). Recovery experiments demonstrated that the use of different AFFFs had no marked influence on the quantitative analysis of fluorosurfactants. Such method works with low-field NMR spectroscopy (1.4 T) as well. Two-dimensional (2D) ¹⁹F COSY NMR was used to make signal assignments for different fluorosurfactant derivatives. The optimized ¹⁹F NMR could quantify the commercially available fluorosurfactants in different AFFFs, identify them being in either the perfluorooctane sulfonate (PFOS) or fluorotelomer sulfonic acid (FTS) categories, and distinguish the head-group of PFOS and FTS derivatives, which exhibits great potentials in the developments of relevant commercial detections.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"4 3","pages":"Article 100097"},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516224000044/pdfft?md5=ef28de5a509c3d91aea064cf464ac76e&pid=1-s2.0-S2772516224000044-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139454054","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}