Journal of magnetic resonance最新文献

Hierarchical maximum likelihood estimation for time-resolved NMR data 时间分辨核磁共振数据的层次最大似然估计。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-04-01 Epub Date: 2026-02-25 DOI: 10.1016/j.jmr.2026.108044

Lennart H. Bosch , Pernille R. Jensen , Nico Striegler , Thomas Unden , Jochen Scharpf , Usman Qureshi , Philipp Neumann , Martin Gierse , John W. Blanchard , Stephan Knecht , Jochen Scheuer , Ilai Schwartz , Martin B. Plenio

Metabolic monitoring and reaction rate estimation using hyperpolarized NMR technology requires accurate quantitative analysis of multidimensional data scenarios. Currently, this analysis is often performed in a two-stage procedure, which is prone to errors in uncertainty propagation and estimation. We propose an approach derived from a Bayesian hierarchical model that intrinsically propagates uncertainties and operates on the full data to maximize the precision at minimal uncertainty. In an analytic treatment, we reduce the estimation procedure to a least-squares optimization problem which can be understood as an extension of the Variable Projection (VarPro) approach for data scenarios with two predictors. We investigate the method’s efficacy in two experiments with hyperpolarized metabolites recorded with conventional high-field NMR devices and a micronscale NMR setup using Nitrogen-Vacancy centers in diamond for detection, respectively. In both examples, the new approach improves estimates compared to Fourier methods and proves operational advantages over a two-stage procedure employing VarPro. While the approach presented is motivated by NMR analysis, it is straightforwardly applicable to further estimation scenarios with similar data structure, such as time-resolved photospectroscopy.

利用超极化核磁共振技术进行代谢监测和反应速率估计需要对多维数据场景进行精确的定量分析。目前，这种分析通常是分两阶段进行的，这在不确定性传播和估计中容易出现错误。我们提出了一种源自贝叶斯层次模型的方法，该方法本质上传播不确定性，并对完整数据进行操作，以最小的不确定性最大化精度。在分析处理中，我们将估计过程简化为最小二乘优化问题，该问题可以理解为具有两个预测因子的数据场景的变量投影（VarPro）方法的扩展。我们在两个实验中研究了该方法的有效性，分别用传统的高场核磁共振设备和微尺度核磁共振装置记录了超极化代谢物，并使用金刚石中的氮空位中心进行检测。在这两个例子中，与傅立叶方法相比，新方法提高了估算值，并证明了与使用VarPro的两阶段程序相比的操作优势。虽然提出的方法是由核磁共振分析驱动的，但它可以直接适用于具有类似数据结构的进一步估计场景，例如时间分辨光谱学。

{"title":"Hierarchical maximum likelihood estimation for time-resolved NMR data","authors":"Lennart H. Bosch , Pernille R. Jensen , Nico Striegler , Thomas Unden , Jochen Scharpf , Usman Qureshi , Philipp Neumann , Martin Gierse , John W. Blanchard , Stephan Knecht , Jochen Scheuer , Ilai Schwartz , Martin B. Plenio","doi":"10.1016/j.jmr.2026.108044","DOIUrl":"10.1016/j.jmr.2026.108044","url":null,"abstract":"<div><div>Metabolic monitoring and reaction rate estimation using hyperpolarized NMR technology requires accurate quantitative analysis of multidimensional data scenarios. Currently, this analysis is often performed in a two-stage procedure, which is prone to errors in uncertainty propagation and estimation. We propose an approach derived from a Bayesian hierarchical model that intrinsically propagates uncertainties and operates on the full data to maximize the precision at minimal uncertainty. In an analytic treatment, we reduce the estimation procedure to a least-squares optimization problem which can be understood as an extension of the Variable Projection (VarPro) approach for data scenarios with two predictors. We investigate the method’s efficacy in two experiments with hyperpolarized metabolites recorded with conventional high-field NMR devices and a micronscale NMR setup using Nitrogen-Vacancy centers in diamond for detection, respectively. In both examples, the new approach improves estimates compared to Fourier methods and proves operational advantages over a two-stage procedure employing VarPro. While the approach presented is motivated by NMR analysis, it is straightforwardly applicable to further estimation scenarios with similar data structure, such as time-resolved photospectroscopy.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"385 ","pages":"Article 108044"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147358017","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

Feasibility of oxygen-enhanced MRI at 7T for assessing lung functional alterations in rats 7T时氧增强MRI评估大鼠肺功能改变的可行性。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-04-01 Epub Date: 2026-02-11 DOI: 10.1016/j.jmr.2026.108031

Dmitrii B. Lebedev , Mikhail V. Gulyaev , Yury A. Pirogov

Oxygen-enhanced (OE) magnetic resonance imaging (MRI) provides a non-invasive approach for assessing lung function. Its application in preclinical models is challenging due to rapid respiratory motion, the intrinsically short T₂* of lung tissue and susceptibility to magnetic field inhomogeneity. These limitations can be largely overcome using standard radial pulse sequences with ultra-short echo, combined with robust T₁-mapping techniques that include B₁⁺-field correction to ensure accurate quantification of regional oxygenation. In this study, we applied the Double Angle Method (DAM) to correct B₁⁺-field inhomogeneity for variable flip angle (VFA) T₁-mapping. Lung images were acquired using a 3D ultrashort echo time (UTE) sequence, enabling assessment of regional T₁ values during ambient air and 95% O₂ inhalation. Both healthy control rats and animals with acute lung inflammation induced by intratracheal lipopolysaccharide (LPS) were studied. Baseline T₁ values in the lung parenchyma were higher in LPS-treated animals compared to controls, with visually identified inflamed regions showing the greatest elevation. Upon inhalation of 95% O₂, T₁ decreased in all groups, but the relative reduction was smaller in LPS-treated lungs than in controls and minimal in inflamed regions, indicating impaired regional oxygen responsiveness. These results demonstrate the feasibility of OE MRI for detecting localized functional impairments in the lungs caused by inflammation.

氧增强（OE）磁共振成像（MRI）提供了一种非侵入性的方法来评估肺功能。由于呼吸运动迅速、肺组织固有的T2*短以及对磁场不均匀性的敏感性，其在临床前模型中的应用具有挑战性。这些限制在很大程度上可以通过使用超短回波的标准径向脉冲序列，结合包括B1+场校正在内的强大的t1制图技术来克服，以确保准确量化区域氧合。在这项研究中，我们应用双角法（DAM）校正B1+场的不均匀性，用于变翻转角（VFA） t1映射。使用3D超短回波时间（UTE）序列获得肺部图像，可以评估环境空气和95% O2吸入时的区域T1值。以健康对照大鼠和气管内脂多糖（LPS）致急性肺炎症动物为研究对象。与对照组相比，lps治疗的动物肺实质的基线T1值更高，视觉识别的炎症区域显示出最大的升高。吸入95% O2后，所有组T1均下降，但lps治疗组的相对下降幅度小于对照组，炎症区最小，表明局部氧反应性受损。这些结果证明了OE MRI检测炎症引起的肺部局部功能损伤的可行性。

{"title":"Feasibility of oxygen-enhanced MRI at 7T for assessing lung functional alterations in rats","authors":"Dmitrii B. Lebedev , Mikhail V. Gulyaev , Yury A. Pirogov","doi":"10.1016/j.jmr.2026.108031","DOIUrl":"10.1016/j.jmr.2026.108031","url":null,"abstract":"<div><div>Oxygen-enhanced (OE) magnetic resonance imaging (MRI) provides a non-invasive approach for assessing lung function. Its application in preclinical models is challenging due to rapid respiratory motion, the intrinsically short T<sub>2</sub>* of lung tissue and susceptibility to magnetic field inhomogeneity. These limitations can be largely overcome using standard radial pulse sequences with ultra-short echo, combined with robust T<sub>1</sub>-mapping techniques that include <em>B</em><sub>1</sub><sup>+</sup>-field correction to ensure accurate quantification of regional oxygenation. In this study, we applied the Double Angle Method (DAM) to correct <em>B</em><sub>1</sub><sup>+</sup>-field inhomogeneity for variable flip angle (VFA) T<sub>1</sub>-mapping. Lung images were acquired using a 3D ultrashort echo time (UTE) sequence, enabling assessment of regional T<sub>1</sub> values during ambient air and 95% O<sub>2</sub> inhalation. Both healthy control rats and animals with acute lung inflammation induced by intratracheal lipopolysaccharide (LPS) were studied. Baseline T<sub>1</sub> values in the lung parenchyma were higher in LPS-treated animals compared to controls, with visually identified inflamed regions showing the greatest elevation. Upon inhalation of 95% O<sub>2</sub>, T<sub>1</sub> decreased in all groups, but the relative reduction was smaller in LPS-treated lungs than in controls and minimal in inflamed regions, indicating impaired regional oxygen responsiveness. These results demonstrate the feasibility of OE MRI for detecting localized functional impairments in the lungs caused by inflammation.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"385 ","pages":"Article 108031"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146215157","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

Characterization of shale using T2–T2∗ relaxation correlation measurements 利用T2-T2 *松弛相关测量表征页岩。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-04-01 Epub Date: 2026-02-18 DOI: 10.1016/j.jmr.2026.108033

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

Magnetic resonance 2D relaxation correlation measurements have been shown to be an incredibly effective way of characterizing complex porous media. Such porous media systems are important for various industries, including the energy industry. Organic shale is a prevalent example in the energy industry. In this paper, we demonstrate the characterization of a shale sample using our new

T_{2}

-

T_{2}^{*}

correlation measurement. We show that the measurement is capable of distinguishing between different hydrogen environments in shale, demonstrating analytical potential for composite porous media. We also show that

T_{2}^{*}

cannot always be used as an analogue to

T_{2}

in heterogeneous media, as shown by peak migrations away from contours of constant

T_{2}

/

T_{2}^{*}

, caused by changing the magnetic field strength.

磁共振二维弛豫相关测量已被证明是表征复杂多孔介质的一种非常有效的方法。这种多孔介质系统对包括能源行业在内的各个行业都很重要。有机页岩在能源行业是一个普遍的例子。在本文中，我们使用我们新的T2-T2 *相关测量证明了页岩样品的表征。我们表明，测量能够区分页岩中不同的氢环境，展示了复合多孔介质的分析潜力。我们还表明T2∗不能总是用作异质介质中T2的模拟物，正如改变磁场强度引起的峰值迁移远离恒定T2/T2∗的轮廓所示。

{"title":"Characterization of shale using T2–T2∗ relaxation correlation measurements","authors":"Dominic O. Couillard, Mohammad Sadegh Zamiri, Bruce J. Balcom, Benedict Newling","doi":"10.1016/j.jmr.2026.108033","DOIUrl":"10.1016/j.jmr.2026.108033","url":null,"abstract":"<div><div>Magnetic resonance 2D relaxation correlation measurements have been shown to be an incredibly effective way of characterizing complex porous media. Such porous media systems are important for various industries, including the energy industry. Organic shale is a prevalent example in the energy industry. In this paper, we demonstrate the characterization of a shale sample using our new <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-<span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span> correlation measurement. We show that the measurement is capable of distinguishing between different hydrogen environments in shale, demonstrating analytical potential for composite porous media. We also show that <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span> cannot always be used as an analogue to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> in heterogeneous media, as shown by peak migrations away from contours of constant <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>/<span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span>, caused by changing the magnetic field strength.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"385 ","pages":"Article 108033"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147313712","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

Unmatched delay line NMR probes for magnetic resonance 无与伦比的延迟线核磁共振探头的磁共振。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-04-01 Epub Date: 2026-02-19 DOI: 10.1016/j.jmr.2026.108032

Nathan Evetts

In magnetic resonance experiments the delay line probe is useful for its broadband impedance match and short ring down times. However, it is usually difficult to construct, and less sensitive than resonant probes. Additionally, the delay line has been widely misused in a manner that further degrades its performance due to an interference effect. We report that significant improvements in signal-to-noise ratio (

\sim

2x) are available when the probe is used with an unmatched termination. This improvement is experimentally demonstrated using both an

^{1}

H NMR signal in a variable electromagnet and with typical “sniffer” coil measurements that characterize

B_{1}

. A quantitative comparison is made with both resonant and bare-coil (“no-tune-no-match”) probes. A novel “echo” type signal is observed in the delay line free induction decay under certain conditions. To alleviate the difficulty of construction we describe an approach using printed circuit board fabrication methods. A PCB delay line probe operating from 4–400 MHz is realized for a magnetometry application. The probe is observed to be robust in cryogenic environments. Finally, we show how to better characterize and optimize a delay line style probe with ordinary vector network analyzer measurements. These practical details are missing from the literature, and relevant to several branches of physics in which broadband spin control is an important technique.

在磁共振实验中，延迟线探头具有宽带阻抗匹配和短停机时间的优点。然而，它通常很难构造，而且灵敏度不如谐振探头。此外，由于干扰效应，延迟线已被广泛滥用，从而进一步降低了其性能。我们报告说，当探头与不匹配的终端一起使用时，信噪比（~ 2x）可以得到显着改善。这种改进是通过实验证明的，使用可变电磁铁中的1H NMR信号和典型的“嗅探器”线圈测量来表征B1。对谐振探头和裸线圈探头（“无调谐-无匹配”）进行了定量比较。在一定条件下，在延迟线自由感应衰减中观察到一种新的“回声”型信号。为了减轻构造的困难，我们描述了一种使用印刷电路板制造方法的方法。实现了一种工作频率为4- 400mhz的PCB延迟线探头。据观察，该探针在低温环境中坚固耐用。最后，我们展示了如何用普通矢量网络分析仪测量更好地表征和优化延迟线式探头。这些实际的细节在文献中是缺失的，并且与物理学的几个分支相关，其中宽带自旋控制是一项重要的技术。

{"title":"Unmatched delay line NMR probes for magnetic resonance","authors":"Nathan Evetts","doi":"10.1016/j.jmr.2026.108032","DOIUrl":"10.1016/j.jmr.2026.108032","url":null,"abstract":"<div><div>In magnetic resonance experiments the delay line probe is useful for its broadband impedance match and short ring down times. However, it is usually difficult to construct, and less sensitive than resonant probes. Additionally, the delay line has been widely misused in a manner that further degrades its performance due to an interference effect. We report that significant improvements in signal-to-noise ratio (<span><math><mo>∼</mo></math></span>2x) are available when the probe is used with an unmatched termination. This improvement is experimentally demonstrated using both an <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H NMR signal in a variable electromagnet and with typical “sniffer” coil measurements that characterize <span><math><msub><mrow><mi>B</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>. A quantitative comparison is made with both resonant and bare-coil (“no-tune-no-match”) probes. A novel “echo” type signal is observed in the delay line free induction decay under certain conditions. To alleviate the difficulty of construction we describe an approach using printed circuit board fabrication methods. A PCB delay line probe operating from 4–400 MHz is realized for a magnetometry application. The probe is observed to be robust in cryogenic environments. Finally, we show how to better characterize and optimize a delay line style probe with ordinary vector network analyzer measurements. These practical details are missing from the literature, and relevant to several branches of physics in which broadband spin control is an important technique.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"385 ","pages":"Article 108032"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146260511","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

17O quadrupolar chemical exchange saturation transfer (Q-CEST) NMR for investigations of molecular dynamics in solids 17O四极性化学交换饱和转移（Q-CEST）核磁共振用于固体分子动力学的研究。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-04-01 Epub Date: 2026-02-26 DOI: 10.1016/j.jmr.2026.108045

Liliya Vugmeyster , Karen Basaves , Riqiang Fu , Sean T. Holmes , Dmitry Ostrovsky

We introduce quadrupolar chemical exchange saturation transfer (Q-CEST) for half-integer quadrupolar nuclei such as oxygen-17 as a complementary NMR tool for studies of molecular dynamics in solids. Experiments on the model compounds NaNO₃ and hydration water in fibrils formed by pyro-glutamate E3 Amyloid-β protein are combined with simulations and theoretical approaches to obtain parameters of molecular motions. We determine the rate constants for 3-site jumps of oxygen atoms in NaNO₃ and rate constants and populations of tetrahedral jumps of hydration water in the proximity to protein surface below the bulk freezing point. The detection is focused on the central transition (CT). However, during the saturation the transmitter is swept across a wide range of frequencies reaching the first satellite transitions. A detailed analysis is provided for CT Q-CEST profiles in the presence of molecular dynamics covering two dynamical transitions occurring approximately in the microsecond and nanosecond time scale ranges and paying special attention to correct inclusion of the dynamics averaging of the second order quadrupolar interaction.

我们介绍了四极性化学交换饱和转移（Q-CEST）的半整数四极性核，如氧-17作为一个补充的核磁共振工具，研究分子动力学的固体。采用模拟和理论相结合的方法，对热谷氨酸E3淀粉样蛋白-β形成的原纤维中的模型化合物NaNO3和水合水进行了实验，获得了分子运动参数。我们测定了NaNO3中氧原子的3位跳变速率常数和蛋白质表面附近水合水在体积冰点以下的四面体跳变速率常数和居群。检测的重点是中央过渡（CT）。然而，在饱和期间，发射机被扫过到达第一颗卫星转换的广泛频率范围。详细分析了分子动力学下的CT Q-CEST谱，包括大约在微秒和纳秒时间尺度范围内发生的两个动力学转变，并特别注意正确包含二阶四极相互作用的动力学平均。

{"title":"17O quadrupolar chemical exchange saturation transfer (Q-CEST) NMR for investigations of molecular dynamics in solids","authors":"Liliya Vugmeyster , Karen Basaves , Riqiang Fu , Sean T. Holmes , Dmitry Ostrovsky","doi":"10.1016/j.jmr.2026.108045","DOIUrl":"10.1016/j.jmr.2026.108045","url":null,"abstract":"<div><div>We introduce quadrupolar chemical exchange saturation transfer (Q-CEST) for half-integer quadrupolar nuclei such as oxygen-17 as a complementary NMR tool for studies of molecular dynamics in solids. Experiments on the model compounds NaNO<sub>3</sub> and hydration water in fibrils formed by pyro-glutamate E3 Amyloid-β protein are combined with simulations and theoretical approaches to obtain parameters of molecular motions. We determine the rate constants for 3-site jumps of oxygen atoms in NaNO<sub>3</sub> and rate constants and populations of tetrahedral jumps of hydration water in the proximity to protein surface below the bulk freezing point. The detection is focused on the central transition (CT). However, during the saturation the transmitter is swept across a wide range of frequencies reaching the first satellite transitions. A detailed analysis is provided for CT Q-CEST profiles in the presence of molecular dynamics covering two dynamical transitions occurring approximately in the microsecond and nanosecond time scale ranges and paying special attention to correct inclusion of the dynamics averaging of the second order quadrupolar interaction.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"385 ","pages":"Article 108045"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147367648","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

Spectral-band-selective multidimensional nuclear magnetic resonance spectroscopy using broadband dipolar recoupling schemes 使用宽带偶极重耦合方案的光谱带选择性多维核磁共振波谱学。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-03-01 Epub Date: 2026-02-04 DOI: 10.1016/j.jmr.2026.108022

Edward P. Saliba , Sarah A. Overall , Alexander B. Barnes

Nuclear magnetic resonance (NMR) spectroscopy is an important analytical tool for probing molecular structures and interactions. For high complexity samples, multidimensional spectroscopy is essential for improving the resolution of NMR data. However, multidimensional experiments cost significant experimental time which scales with the number of indirect points. This is particularly challenging when dealing with highly dispersed nuclei, such as ¹³C, due to the large chemical shift range, with large regions that are spectrally empty. Herein, we describe a method for limiting the spectral width of dipolar based multidimensional NMR experiments in the indirect dimension in a manner that can be easily integrated into relaxation and distance measuring schemes. We demonstrate the acquisition of narrow strips of broadband homonuclear recoupling ¹³C-¹³C correlation spectra on a range of biomolecular and cellular samples, allowing targeted acquisition of high-resolution spectra of the region of interest with a significant reduction in the acquisition time. We also demonstrate the use of the spectral-band-selective method for allowing fast acquisition of RFDR build-up experiments. The band-selective method is easy to implement in any dipolar-based multidimensional pulse sequence by an addition of one pulse per band-selected indirect dimension and a slight modification of the phase cycle.

核磁共振波谱是探测分子结构和相互作用的重要分析工具。对于高复杂性的样品，多维光谱技术对于提高核磁共振数据的分辨率至关重要。然而，多维实验耗费大量的实验时间，且实验时间与间接点的数量成正比。这在处理高度分散的原子核（如13C）时尤其具有挑战性，因为化学位移范围大，光谱上的大区域是空的。在此，我们描述了一种在间接维度上限制基于偶极子的多维核磁共振实验光谱宽度的方法，这种方法可以很容易地集成到弛豫和距离测量方案中。我们展示了在一系列生物分子和细胞样品上获取宽带同核重耦合13C-13C相关光谱的窄带，允许有针对性地获取感兴趣区域的高分辨率光谱，同时显著减少了采集时间。我们还演示了使用频谱波段选择方法来允许快速获取RFDR构建实验。在任何基于偶极子的多维脉冲序列中，通过在每个带选间接维中增加一个脉冲和稍微修改相位周期，可以很容易地实现带选择方法。

{"title":"Spectral-band-selective multidimensional nuclear magnetic resonance spectroscopy using broadband dipolar recoupling schemes","authors":"Edward P. Saliba , Sarah A. Overall , Alexander B. Barnes","doi":"10.1016/j.jmr.2026.108022","DOIUrl":"10.1016/j.jmr.2026.108022","url":null,"abstract":"<div><div>Nuclear magnetic resonance (NMR) spectroscopy is an important analytical tool for probing molecular structures and interactions. For high complexity samples, multidimensional spectroscopy is essential for improving the resolution of NMR data. However, multidimensional experiments cost significant experimental time which scales with the number of indirect points. This is particularly challenging when dealing with highly dispersed nuclei, such as <sup>13</sup>C, due to the large chemical shift range, with large regions that are spectrally empty. Herein, we describe a method for limiting the spectral width of dipolar based multidimensional NMR experiments in the indirect dimension in a manner that can be easily integrated into relaxation and distance measuring schemes. We demonstrate the acquisition of narrow strips of broadband homonuclear recoupling <sup>13</sup>C-<sup>13</sup>C correlation spectra on a range of biomolecular and cellular samples, allowing targeted acquisition of high-resolution spectra of the region of interest with a significant reduction in the acquisition time. We also demonstrate the use of the spectral-band-selective method for allowing fast acquisition of RFDR build-up experiments. The band-selective method is easy to implement in any dipolar-based multidimensional pulse sequence by an addition of one pulse per band-selected indirect dimension and a slight modification of the phase cycle.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"384 ","pages":"Article 108022"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146145366","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

Automated frequency tuning for broadband NMR spectroscopy: A LabVIEW-based solution 宽带核磁共振光谱的自动频率调谐：基于labview的解决方案

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.jmr.2026.108020

Yanan Li , Hadrien Mayaffre , Florian Bärtl , Steffen Krämer , Mladen Horvatić

This work introduces an automated frequency-tuning system for Nuclear Magnetic Resonance (NMR) spectroscopy. Developed using LabVIEW software, the system is designed for the top-tuning configurations of NMR probes commonly used in solid-state physics for broad-frequency-sweep spectra at very low temperatures and/or high magnetic fields. The system integrates a stepper motor, driver, phase shifter, and network analyzer to enable rapid, precise, and efficient probe tuning. Traditional manual tuning for broadband NMR is labor-intensive and time-consuming, often hindering timely data acquisition. Our automated solution significantly reduces tuning time and minimizes user intervention, thereby enhancing the efficiency and accuracy of NMR measurements. The system’s effectiveness is demonstrated with experimental ⁶³Cu and ⁶⁵Cu NMR results from an SrCu₂(BO₃)₂ sample in a high magnetic field. This automation is particularly valuable for streamlining research in ultra-high magnetic fields, which are exceptionally expensive to produce.

本文介绍了一种用于核磁共振（NMR）光谱的自动频率调谐系统。该系统使用LabVIEW软件开发，专为固态物理中常用的NMR探针的顶调谐配置而设计，用于在极低温度和/或高磁场下的宽频率扫描光谱。该系统集成了步进电机，驱动器，移相器和网络分析仪，以实现快速，精确和有效的探头调谐。传统的宽带核磁共振手动调优既费时又费力，往往影响数据的及时采集。我们的自动化解决方案显著减少了调优时间，最大限度地减少了用户干预，从而提高了核磁共振测量的效率和准确性。用高磁场下SrCu2(BO3)2样品的63Cu和65Cu核磁共振实验结果证明了该系统的有效性。这种自动化对于简化超高磁场的研究尤其有价值，超高磁场的生产成本非常高。

{"title":"Automated frequency tuning for broadband NMR spectroscopy: A LabVIEW-based solution","authors":"Yanan Li , Hadrien Mayaffre , Florian Bärtl , Steffen Krämer , Mladen Horvatić","doi":"10.1016/j.jmr.2026.108020","DOIUrl":"10.1016/j.jmr.2026.108020","url":null,"abstract":"<div><div>This work introduces an automated frequency-tuning system for Nuclear Magnetic Resonance (NMR) spectroscopy. Developed using LabVIEW software, the system is designed for the top-tuning configurations of NMR probes commonly used in solid-state physics for broad-frequency-sweep spectra at very low temperatures and/or high magnetic fields. The system integrates a stepper motor, driver, phase shifter, and network analyzer to enable rapid, precise, and efficient probe tuning. Traditional manual tuning for broadband NMR is labor-intensive and time-consuming, often hindering timely data acquisition. Our automated solution significantly reduces tuning time and minimizes user intervention, thereby enhancing the efficiency and accuracy of NMR measurements. The system’s effectiveness is demonstrated with experimental <sup>63</sup>Cu and <sup>65</sup>Cu NMR results from an SrCu<sub>2</sub>(BO<sub>3</sub>)<sub>2</sub> sample in a high magnetic field. This automation is particularly valuable for streamlining research in ultra-high magnetic fields, which are exceptionally expensive to produce.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"384 ","pages":"Article 108020"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102388","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

Heisenberg spin exchange and relaxation dynamics in EPR oximetry: A photoinduced transition from non-adiabatic rapid-sweeps to the rapid-scan regime EPR血氧测定中的海森堡自旋交换和弛豫动力学：从非绝热快速扫描到快速扫描的光诱导转变

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-03-01 Epub Date: 2026-01-27 DOI: 10.1016/j.jmr.2026.108021

Florian Johannsen, Malte Drescher

Rapid-scan electron paramagnetic resonance spectroscopy (RS EPR) has emerged as a powerful tool to monitor light-induced processes accompanied by changes of the EPR lineshape and is frequently used for measuring local oxygen concentrations. Here we use LiPc (lithium phthalocyanine) and CTPO (3-Carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-oxyl) as spin probes and demonstrate control over the oxygen partial pressure through a photochemical reaction. The resulting changes in

{pO}_{2}

manifest as characteristic distortions of the EPR lineshape and reveal how Heisenberg spin exchange influences relaxation dynamics. As a proof-of-concept, we investigate photopolymerization at reduced oxygen levels. These results highlight the potential of RS for studying oxidation processes in biochemical systems.

快速扫描电子顺磁共振波谱（RS EPR）已成为监测伴随EPR线形变化的光诱导过程的有力工具，并经常用于测量局部氧浓度。在这里，我们使用LiPc（酞菁锂）和CTPO（3-氨基甲酰-2,2,5,5-四甲基-3-吡咯啉-1-氧基）作为自旋探针，并通过光化学反应证明了对氧分压的控制。由此产生的pO2的变化表现为EPR线形状的特征扭曲，并揭示了海森堡自旋交换如何影响弛豫动力学。作为概念验证，我们研究了在低氧水平下的光聚合。这些结果突出了RS在研究生化系统氧化过程中的潜力。

引用次数: 0

Solvent PRE and effective near surface electrostatics: theory, methods, and biological insights 溶剂PRE和有效的近表面静电：理论、方法和生物学见解。

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-03-01 Epub Date: 2025-12-04 DOI: 10.1016/j.jmr.2025.108007

Sydney Griggs, Yusuke Okuno

Electrostatic interactions are central to biomolecular structure, dynamics, and function, yet experimentally probing local electrostatic potentials with residue-level resolution remains challenging. Solvent paramagnetic relaxation enhancement (sPRE) offers a powerful nuclear magnetic resonance (NMR) approach to directly quantify near-surface electrostatic environments without requiring structural information. In this review, we outline the theoretical framework underlying sPRE, emphasizing recent advances in spectral density analysis, spatial decomposition, and the influence of intermolecular potentials. We discuss the effective near-surface electrostatic potential (ENS), a derived quantity that captures local electrostatic fields by comparing transverse relaxation rates induced by paramagnetic cosolutes of differing charge. Applications to proteins, nucleic acids, and intrinsically disordered systems highlight the ability of sPRE and ENS to reveal electrostatic modulation in complex biological contexts, including phase separation, ion atmosphere structure, and protein–nucleic acid interactions. We also examine current limitations and provide a theoretical basis for interpreting ENS, offering perspectives for future methodological developments in electrostatics mapping by NMR.

静电相互作用是生物分子结构、动力学和功能的核心，但通过残留级分辨率实验探测局部静电电位仍然具有挑战性。溶剂顺磁弛豫增强（sPRE）提供了一种强大的核磁共振（NMR）方法来直接量化近表面静电环境，而不需要结构信息。在这篇综述中，我们概述了sPRE的理论框架，强调了在光谱密度分析、空间分解和分子间电位影响方面的最新进展。我们讨论了有效近表面静电势（ENS），这是一个通过比较不同电荷的顺磁co溶质诱导的横向弛豫率来捕获局部静电场的导出量。在蛋白质、核酸和内在无序系统中的应用突出了sPRE和ENS在复杂生物环境中揭示静电调制的能力，包括相分离、离子气氛结构和蛋白质-核酸相互作用。我们还研究了目前的局限性，并为解释ENS提供了理论基础，为未来核磁共振静电制图的方法发展提供了前景。

{"title":"Solvent PRE and effective near surface electrostatics: theory, methods, and biological insights","authors":"Sydney Griggs, Yusuke Okuno","doi":"10.1016/j.jmr.2025.108007","DOIUrl":"10.1016/j.jmr.2025.108007","url":null,"abstract":"<div><div>Electrostatic interactions are central to biomolecular structure, dynamics, and function, yet experimentally probing local electrostatic potentials with residue-level resolution remains challenging. Solvent paramagnetic relaxation enhancement (sPRE) offers a powerful nuclear magnetic resonance (NMR) approach to directly quantify near-surface electrostatic environments without requiring structural information. In this review, we outline the theoretical framework underlying sPRE, emphasizing recent advances in spectral density analysis, spatial decomposition, and the influence of intermolecular potentials. We discuss the effective near-surface electrostatic potential (ENS), a derived quantity that captures local electrostatic fields by comparing transverse relaxation rates induced by paramagnetic cosolutes of differing charge. Applications to proteins, nucleic acids, and intrinsically disordered systems highlight the ability of sPRE and ENS to reveal electrostatic modulation in complex biological contexts, including phase separation, ion atmosphere structure, and protein–nucleic acid interactions. We also examine current limitations and provide a theoretical basis for interpreting ENS, offering perspectives for future methodological developments in electrostatics mapping by NMR.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"384 ","pages":"Article 108007"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145800915","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

A high-performance ceramic volume coil for preclinical MRI 一种用于临床前MRI的高性能陶瓷体积线圈

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2026-02-01 Epub Date: 2026-01-23 DOI: 10.1016/j.jmr.2026.108019

Conner S. Ubert , Sergey V. Petryakov , Maciej M. Kmiec , Ryan C. O'Connell , Victor B. Kassey , Periannan Kuppusamy

A novel volume radio-frequency (RF) coil built around a cylindrical ceramic dielectric (relative permittivity ε_r = 270) was developed for high-field small-animal magnetic resonance imaging (MRI). Finite element simulations were used to optimize the resonator geometry, resulting in an inner diameter of 30 mm, an outer diameter of 47 mm and a length of 43 mm, which is tuned to approximately 400 MHz resonance frequency. The coil is tuned and matched solely by two inductively coupled loops, eliminating the need for lumped-element tuning and matching capacitors. In the loaded state the coil exhibits a quality factor of 105 and very uniform transmit fields, with a B₁ homogeneity of 98.2% in the unloaded condition. Phantom experiments show 97% signal uniformity across 0.7 mm slices and a signal-to-noise ratio (SNR) ranging from 55 to 220 along the coil axis. B₁ mapping confirms accurate excitation (mean actual-to-nominal flip-angle ratio = 1.05) with a coefficient of variation of 1.9%. High-resolution mouse images demonstrate that the ceramic resonator provides excellent anatomical detail, confirming its utility for preclinical MRI. This dielectric-resonator design delivers B₁ homogeneity comparable to or better than conventional coils while simplifying hardware, improving tuning stability and reducing RF losses, establishing it as a cost-effective and robust solution for quantitative high-field preclinical MRI.

采用圆柱形陶瓷介质（相对介电常数εr = 270）构建了一种新型体积射频线圈，用于高场小动物磁共振成像（MRI）。利用有限元模拟优化了谐振腔的几何形状，得到了内径为30 mm，外径为47 mm，长度为43 mm的谐振腔，谐振频率约为400 MHz。该线圈仅由两个电感耦合回路调谐和匹配，消除了对集总元件调谐和匹配电容器的需要。在负载状态下，线圈的质量系数为105，发射场非常均匀，在无负载状态下，B1均匀性为98.2%。模拟实验显示，在0.7毫米的切片上，97%的信号均匀性和沿线圈轴的信噪比（SNR）在55到220之间。B1映射证实了准确的激励（平均实际与标称翻转角比= 1.05），变异系数为1.9%。高分辨率小鼠图像表明，陶瓷谐振器提供了极好的解剖细节，证实了其在临床前MRI中的实用性。这种介电谐振器设计提供了与传统线圈相当或更好的B1均匀性，同时简化了硬件，提高了调谐稳定性并减少了RF损耗，使其成为定量高场临床前MRI的经济高效且强大的解决方案。

{"title":"A high-performance ceramic volume coil for preclinical MRI","authors":"Conner S. Ubert , Sergey V. Petryakov , Maciej M. Kmiec , Ryan C. O'Connell , Victor B. Kassey , Periannan Kuppusamy","doi":"10.1016/j.jmr.2026.108019","DOIUrl":"10.1016/j.jmr.2026.108019","url":null,"abstract":"<div><div>A novel volume radio-frequency (RF) coil built around a cylindrical ceramic dielectric (relative permittivity ε<sub>r</sub> = 270) was developed for high-field small-animal magnetic resonance imaging (MRI). Finite element simulations were used to optimize the resonator geometry, resulting in an inner diameter of 30 mm, an outer diameter of 47 mm and a length of 43 mm, which is tuned to approximately 400 MHz resonance frequency. The coil is tuned and matched solely by two inductively coupled loops, eliminating the need for lumped-element tuning and matching capacitors. In the loaded state the coil exhibits a quality factor of 105 and very uniform transmit fields, with a B<sub>1</sub> homogeneity of 98.2% in the unloaded condition. Phantom experiments show 97% signal uniformity across 0.7 mm slices and a signal-to-noise ratio (SNR) ranging from 55 to 220 along the coil axis. B<sub>1</sub> mapping confirms accurate excitation (mean actual-to-nominal flip-angle ratio = 1.05) with a coefficient of variation of 1.9%. High-resolution mouse images demonstrate that the ceramic resonator provides excellent anatomical detail, confirming its utility for preclinical MRI. This dielectric-resonator design delivers B<sub>1</sub> homogeneity comparable to or better than conventional coils while simplifying hardware, improving tuning stability and reducing RF losses, establishing it as a cost-effective and robust solution for quantitative high-field preclinical MRI.</div></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"383 ","pages":"Article 108019"},"PeriodicalIF":1.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022783","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