Journal of magnetic resonance最新文献_第5页

Advancing quantitative NMR for high-precision isotopic analysis with rnmrfit 2.0 推进定量核磁共振高精度同位素分析与rnmrfit 2.0。

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-10-31 DOI: 10.1016/j.jmr.2025.107991

Kathy Sharon Isaac , Phuong Mai Le , Theodore Street , Akila Wijerathna-Yapa , Stanislav Sokolenko

{"title":"Advancing quantitative NMR for high-precision isotopic analysis with rnmrfit 2.0","authors":"Kathy Sharon Isaac , Phuong Mai Le , Theodore Street , Akila Wijerathna-Yapa , Stanislav Sokolenko","doi":"10.1016/j.jmr.2025.107991","DOIUrl":"10.1016/j.jmr.2025.107991","url":null,"abstract":"<div><div>Quantitative NMR is widely utilized in isotopic ratio measurement for determining the origins and authenticity of chemical compounds. Achieving high precision required for such analyses depends on accurately separating signal from noise, which is essential for reliable quantification of resonance peak areas. In this study, we present rnmrfit 2.0, an NMR peak-fitting tool tailored for high precision isotopic analysis. This new version incorporates semi-global peak fitting with automated peak region selection, achieving greater robustness and computational efficiency than previously reported. The newly developed software was used to explore the impact of two common spectral processing techniques, line broadening and zero filling, as well as the choice of baseline span on peak fitting precision. All three were found to have a significant impact on fit precision, with optimal settings for line broadening and zero filling deviating from what is commonly recommended for 13C spectra, at 1–3 Hz and 0.5–1.0, respectively. Compared to commercial tools including TopSpin and MestReNova, rnmrfit demonstrated superior precision and trueness, achieving precision as low as 0.26% for 2H and 0.16% for 13C. The new version of rnmrfit is available as an open-source executable, offering a scalable solution for isotopic analysis with minimal user input, paving the way for more reliable isotopic quantification.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"381 ","pages":"Article 107991"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145524922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An experimental demonstration of the use of a cryogen-free system for high-resolution 1D and 2D solid and liquid state NMR 无低温系统用于高分辨率一维和二维固体和液态核磁共振的实验演示

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-10-08 DOI: 10.1016/j.jmr.2025.107985

Eugeny Kryukov , Alexander Karabanov , Denis Langlais , Dinu Iuga , Shashwata Moitra , Jeremy Good

引用次数: 0

Magnetic resonance imaging using a straight wire magnetic field for spatial signal encoding: Imaging verification with 2D experiments and 3D modeling 使用直线磁场进行空间信号编码的磁共振成像：用二维实验和三维建模进行成像验证。

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-10-30 DOI: 10.1016/j.jmr.2025.107990

Kaja Tušar , Igor Serša

{"title":"Magnetic resonance imaging using a straight wire magnetic field for spatial signal encoding: Imaging verification with 2D experiments and 3D modeling","authors":"Kaja Tušar , Igor Serša","doi":"10.1016/j.jmr.2025.107990","DOIUrl":"10.1016/j.jmr.2025.107990","url":null,"abstract":"<div><div>Spatial encoding in MRI is usually performed using gradient coils that produce a linearly increasing magnetic field <em>B</em><sub><em>z</em></sub> in a desired spatial direction such that its gradient is constant. However, it has been shown that spatial encoding in MRI can also be performed with coils that produce nonlinear magnetic fields. In this study, the performance of different types of nonlinear encoding coils, which have a simple design based on the use of a straight wire segment as a building block and a source of a highly nonlinear magnetic field, was experimentally tested in 2D and by simulation in 3D on coils with a nonsymmetric and a symmetric arrangement of these wire segments. All images were reconstructed using our newly presented method, in which the signals are first transformed from the time- to the frequency-domain, yielding a distorted image (spectrum), which is then geometrically and intensity corrected. The quality of the reconstructed images was quantified by comparing them with corresponding reference images obtained with conventional gradient coils. The reconstruction method was accurate for all tested encoding coils and showed that the symmetric coil type produced results that required significantly less corrections compared to the nonsymmetric coil type. Quantitative image quality measurements showed that all encoding coils, despite large differences in the magnetic field of the encoding coils, produce images of similar quality. The results of the study may help advance the design of “gradient” coils towards freer geometries, higher magnetic field gradients or lower inductance and thus faster switching times.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"381 ","pages":"Article 107990"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145446981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Passive shimming performance in 3 T MRI systems: Influence of shim parameters under varying magnet field distributions 3t MRI系统的被动摆振性能：不同磁场分布下摆振参数的影响。

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-09-27 DOI: 10.1016/j.jmr.2025.107969

Jinhao Liu , Miutian Wang , Wenchen Wang , Yaohui Wang , Wenhui Yang , Weimin Wang , Feng Liu

{"title":"Passive shimming performance in 3 T MRI systems: Influence of shim parameters under varying magnet field distributions","authors":"Jinhao Liu , Miutian Wang , Wenchen Wang , Yaohui Wang , Wenhui Yang , Weimin Wang , Feng Liu","doi":"10.1016/j.jmr.2025.107969","DOIUrl":"10.1016/j.jmr.2025.107969","url":null,"abstract":"<div><div>This study proposes a simple and computationally efficient method to optimize the structural design parameters of passive shimming slots, aiming to improve magnetic field homogeneity in cryogen-free 3 T/200 mm superconducting magnets used across diverse application environments. The proposed method combines Latin Hypercube Sampling (LHS), utilizing over 300 sampled configurations, with a linear programming (LP)-based optimization framework to explore high-dimensional design spaces while adhering to structural constraints. The method was applied to four distinct magnets, each characterized by unique field inhomogeneity patterns resulting from manufacturing and assembly variations. Through harmonic decomposition, system-specific sensitivities were identified and effectively mitigated using customized passive shimming strategies tailored to each magnet. The optimization process achieved substantial improvements in magnetic field homogeneity, with peak-to-peak (PP) values enhanced to 12.16, 10.04, 27.28, and 54.59 parts per million (ppm) for Magnets 1 to 4, respectively. Correspondingly, the root-mean-square error (RMSE) homogeneity improved to 2.28, 1.98, 5.07, and 9.68 ppm. Furthermore, the magnitudes of all harmonic terms were reduced by 1-2 orders of magnitude, with suppression levels exceeding 90%, while minimizing the use of ferromagnetic materials. The practical feasibility of the proposed strategy was validated on-site: Magnet 1 successfully delivered high-quality animal MRI imaging with excellent signal-to-noise ratios (SNRs), and the remaining magnets are currently undergoing final calibration and delivery. This work presents a robust and scalable optimization framework for precise and resource-efficient passive shimming, offering valuable guidance for future magnet design, customization, and deployment in biomedical and industrial applications.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"381 ","pages":"Article 107969"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145202542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

T2–T2∗ relaxation correlation measurement T2-T2 *松弛相关测量。

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-10-13 DOI: 10.1016/j.jmr.2025.107987

Dominic O. Couillard, Peiyuan Yan, Mohammad Sadegh Zamiri, Bruce J. Balcom, Benedict Newling

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NMR of chemical exchange: Revisited 核磁共振化学交换：重访

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-09-24 DOI: 10.1016/j.jmr.2025.107968

Janez Stepišnik , Aleš Mohorič

引用次数: 0

A simple algorithm to suppress diagonal peaks in high-resolution homonuclear chemical shift correlation NMR spectra 一种抑制高分辨率同核化学位移相关核磁共振谱对角峰的简单算法。

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-12-01 Epub Date: 2025-09-13 DOI: 10.1016/j.jmr.2025.107967

Shengyu Zhang , Jhinuk Saha , Yuchen Li , Xinhua Peng , Ryan P. McGlinchey , Ayyalusamy Ramamoorthy , Riqiang Fu

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Cryogenic magic-angle spinning continuous wave EPR and DNP spectroscopy at 7 T with a gyrotron 7 T低温魔角旋转连续波EPR和DNP光谱学

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-11-01 Epub Date: 2025-08-08 DOI: 10.1016/j.jmr.2025.107938

Marthe Millen , Nicholas Alaniva , Snædís Björgvinsdóttir , Alexander Däpp , Ioannis Gr. Pagonakis , Wolfgang Harneit , Alexander B. Barnes

{"title":"Cryogenic magic-angle spinning continuous wave EPR and DNP spectroscopy at 7 T with a gyrotron","authors":"Marthe Millen , Nicholas Alaniva , Snædís Björgvinsdóttir , Alexander Däpp , Ioannis Gr. Pagonakis , Wolfgang Harneit , Alexander B. Barnes","doi":"10.1016/j.jmr.2025.107938","DOIUrl":"10.1016/j.jmr.2025.107938","url":null,"abstract":"<div><div>Dynamic nuclear polarization (DNP) relies on the transfer of electron polarization to nuclei through microwave irradiation and is typically performed under cryogenic magic-angle spinning (MAS) at high magnetic fields. Gyrotrons are commonly used microwave sources in DNP because of their ability to produce high-power microwaves over a broad frequency range. An important step towards a more in-depth understanding of DNP mechanisms and rational optimization of DNP performance is the access to instrumentation, which can provide information about the DNP process. Continuous wave (CW) electron paramagnetic resonance (EPR) can reveal important information on the electron spin system during DNP experiments. Here, we present a dual CW EPR/DNP spectrometer operated under MAS at 100 K and 7 T using a frequency-agile 198 GHz gyrotron. The measured sensitivity for CW EPR at 198 GHz using an MAS stator is 4 <span><math><mo>×</mo></math></span> 10<sup>13</sup> spins/(G<span><math><msqrt><mrow><mi>H</mi><mi>z</mi></mrow></msqrt></math></span>). To illustrate the electron and nuclear detection capabilities of our setup, DNP profiles and CW EPR spectra of a diamond powder and a trityl sample were recorded under the same conditions, specifically at 100 K and under MAS.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"380 ","pages":"Article 107938"},"PeriodicalIF":1.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144866960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimisation and impact of gradient waveform modulation on Non-uniform Oscillating Gradient Spin-Echo sequences for microstructural characterisation 梯度波形调制对非均匀振荡梯度自旋回波序列微结构表征的优化及影响

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-11-01 Epub Date: 2025-08-08 DOI: 10.1016/j.jmr.2025.107940

Melisa L. Gimenez , Pablo Jimenez , Leonardo A. Pedraza Pérez , Diana Betancourth , Analia Zwick , Gonzalo A. Álvarez

{"title":"Optimisation and impact of gradient waveform modulation on Non-uniform Oscillating Gradient Spin-Echo sequences for microstructural characterisation","authors":"Melisa L. Gimenez , Pablo Jimenez , Leonardo A. Pedraza Pérez , Diana Betancourth , Analia Zwick , Gonzalo A. Álvarez","doi":"10.1016/j.jmr.2025.107940","DOIUrl":"10.1016/j.jmr.2025.107940","url":null,"abstract":"<div><div>Neurological diseases often result in changes at microscopic scales in the nervous system, emphasising the need for non-invasive imaging techniques that can quantify these alterations as potential biomarkers for diagnosis. Diffusion-weighted magnetic resonance imaging (DWI), particularly using modulated gradient spin-echo (MGSE) sequences, has significantly advanced in revealing tissue microstructure by probing molecular diffusion. Among the MGSE sequences, the Non-uniform Oscillating Gradient Spin-Echo (NOGSE) sequence generates a contrast based on selective microstructure sizes through a signal decay-shift, rather than probing conventional decay rates. In this study, we evaluate the performance of NOGSE in estimating microstructure sizes using a preclinical MRI scanner. Our results show that while sharp, instantaneous gradient modulations maximise the decay-shift, smooth gradient modulations still provide meaningful contrast. Through a combination of phantom experiments, numerical simulations and information-theoretic analysis, we optimise NOGSE parameters for accurate microstructural size estimation under both sharp and smooth gradient modulations. We identify optimal NOGSE parameters that are compatible with preclinical hardware constraints, providing reliable microstructure size characterisation. Especially smooth gradient modulations expand the range of compatible MRI scanners and are almost suitable for <em>in-vivo</em> applications. These findings represent a step toward developing quantitative imaging tools for probing microstructural features in diffusion-weighted magnetic resonance imaging.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"380 ","pages":"Article 107940"},"PeriodicalIF":1.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144842914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Specificity and reactivity of bromoacrylaldehyde spin labels 溴丙醛自旋标记的特异性和反应性

IF 1.9 3区化学

Journal of magnetic resonance Pub Date : 2025-11-01 Epub Date: 2025-08-12 DOI: 10.1016/j.jmr.2025.107953

Dominik Gendreizig , Christina Elsner , Svetlana Kucher , Gunnar Jeschke , Alistair J. Fielding , Enrica Bordignon

{"title":"Specificity and reactivity of bromoacrylaldehyde spin labels","authors":"Dominik Gendreizig , Christina Elsner , Svetlana Kucher , Gunnar Jeschke , Alistair J. Fielding , Enrica Bordignon","doi":"10.1016/j.jmr.2025.107953","DOIUrl":"10.1016/j.jmr.2025.107953","url":null,"abstract":"<div><div>Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labelling provides information on structure and dynamics of biomolecules. Increasing the availability of spin labels with different properties is an elegant way to foster a more accurate analysis of the EPR data in relation to the biological problem investigated. In this study, we present a comparative investigation of labelling efficiency, surface accessibility, site specificity and width of the distance distributions obtained on two proteins with the nitroxide-based bromoacrylaldehyde spin label (BASL) versus the two commercial spin labels MTSL (methanethiosulfonate spin label) and MAP (maleimido proxyl). Based on the predicted distances from a rotamer library approach and on the experimental distance distributions, BASL is shown to provide generally narrower distance distributions compared to the other nitroxide labels. The exquisite surface specificity of BASL with respect to MAP could be successfully exploited to selectively label surface cysteines in proteins containing a high number of native cysteines. In addition, the distinct site-reactivity of BASL and MAP towards two surface-exposed cysteines was leveraged for orthogonal labelling strategies with nitroxide and gadolinium labels.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"380 ","pages":"Article 107953"},"PeriodicalIF":1.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0