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| 1 | Progresses of hyperpolarized ^(129)Xe NMR application in porous materials and catalysis显示文摘^(129)Xe NMR has been proven to be a powerful tool to investigate the structure of porousmaterials. Xenon is a monatomic noble gas which could be used as a probe due to theextremely sensitive to its local environment. Optical pumping techniques for production ofhyperpolarized (HP) xenon have led to an increase of sensitivity up to orders of magnitudecompared with traditional ^(129)Xe NMR. This review summarizes the application of thistechnique in porous materials and heterogeneous catalysis in recent ten years, involving ofzeolites, metal-organic frameworks (MOFs), catalytic process and kinetics. | Benhan Fan Shutao Xu Yingxu Wei Zhongmin Liu | 2021 | Magnetic Resonance Letters2021，1，1： | 3 |
| 2 | NMR assignments and characterization of the DNA-binding domain of Arabidopsis transcription factor WRKY11--Dedicated to Professor Xiuwen Han on the occasion of her 80th birthday显示文摘The WRKY proteins are a family of plant-specific transcription factors(TFs)that are widely involved in plant development and anti-stress responses.Arabidopsis WRKY11(AtWRKY11)functions in regulating plant defense against abiotic stress and belongs to the Ild subgroup of WRKY TFs.We herein report the expres sion,purification and preliminary structural characterization of AtWRKY11 DNA-binding domain(DBD)using solution NMR Almost complete backbone chemical shift assignments of AtWRKY11-DBD have been ob-tained.Chemical shift-based secondary structure analysis suggests that AtWRKY11-DBD may exhibit local conformational diferences from the X-ray structure of the C-terminal WRKY domain of AtWRKY1,particularly in the β1 and β5 strands.Our current study provides the basis for further structural and interactional studies. | Jiannan Wang Yaling Lin Qinjun Zhu Jingfeng Zhang Maili Liu Yunfei Hu | 2021 | Magnetic Resonance Letters2021，1，2： | 2 |
| 3 | Evaluation of injuries caused by coronavirus disease 2019 using multi-nuclei magnetic resonance imaging显示文摘The ongoing pandemic of coronavirus disease 2019(COVID-19)has been a great burden for the healthcare system in many countries because of its high transmissibility,severity,and fatality.Chest radiography and computed tomography(CT)play a vital role in the diagnosis,detection of complications,and prognostication of COVID-19.Additionally,magnetic resonance imaging(MRI),especially multi-nuclei MRI,is another important imaging technique for disease diagnosis because of its good soft tissue contrast and the ability to conduct structural and functional imaging,which has also been used to evaluate COVID-19-related organ injuries in previous studies.Herein,we briefly reviewed the recent research on multi-nuclei MRI for evaluating injuries caused by COVID-19 and the clinical 1 H MRI techniques and their applications for assessing injuries in lungs,brain,and heart.Moreover,the emerging hyperpolarized 129Xe gas MRI and its applications in the evaluation of pulmonary structures and functional abnormalities caused by COVID-19 were also reviewed. | Qian Zhou Qiuchen Rao Haidong Li Ming Zhang Xiuchao Zhao Lei Shi Chaohui Ye Xin Zhou | 2021 | Magnetic Resonance Letters2021，1，1： | 1 |
| 4 | Influence of hierarchical ZSM-5 catalysts with various acidity on the dehydration of glycerol to acrolein显示文摘The main challenge in the dehydration of glycerol to acrolein lies in overcoming catalystdeactivation and improving the selectivity to acrolein. The relationship between theacidity in the mesoporous channels and catalytic performance of glycerol dehydration israrely reported. In this work, to investigate the influence of acidity in the mesoporouschannels of hierarchical ZSM-5 catalysts on the dehydration of glycerol to acrolein, a seriesof hierarchical ZSM-5 zeolites with comparable mesoporous volume and mesoporous sizebut different acid properties in mesopores have been successfully prepared via alkalinetreatment. The sample with the abundant mesoporosity and highest acidity display thebest performance. | Shufang Zhao Songlin He Kyung Du Kim Lizhuo Wang Ryong Ryoo Zichun Wang Jun Huang | 2021 | Magnetic Resonance Letters2021，1，1： | 1 |
| 5 | RF power design optimization in MRI system显示文摘Magnetic resonance image quality and patient safety have been the focus of engineering and research ever since the invention of equipment in the early 1970s.In high field(or ultrahigh field)MRI systems,the emerging techniques induced by B1 field challenges have promoted various potential solutions.This paper describes the relationship between RF power and B1þfield performance,and the overall requirements considered in RF subsystem design.The design of the RF in the MR system is systematically summarized,including the entire transmission chain,sequence algorithm and RF pulse design,and the probabilities for improvement and optimization in the system design are indicated.At the same time,the radio frequency related issues of the human whole-body 7 T MR and animal MR systems are discussed,especially the promising future showed by the technologies such as radio frequency parallel transmission technology in the ultrahigh field. | Baogui Zhang Kun Wang Tianzi Jiang | 2021 | Magnetic Resonance Letters2021，1，1： | 1 |
| 6 | Conformational dynamics in GPCR signaling by NMR显示文摘G-protein-coupled receptors(GPCRs)mediate a wide range of cellular responses to various ligands or stimuli,and are the most important drug targets associated with human diseases.While major advances in GPCR structural biology have greatly deepened our understanding of its activation mechanism,the highly complex changes in the structural dynamics of GPCRs during activation remain underdetermined and their links to physiological functions largely unknown.Solution nuclear magnetic resonance(NMR)spectroscopy is an essential technique that allows the characterization of protein structural dynamics at atomic level,and has been applied in the studies of GPCR structural-function relationship in the past decade.Herein,we summarize a few specific studies in which solution NMR methods were employed and provided novel insights into questions difficult to be addressed by other methods. | Yunfei Hu Changwen Jin | 2022 | Magnetic Resonance Letters2022，2，3： | 1 |
| 7 | Active shim coils design for Halbach magnet based on inverse boundary element method显示文摘With advantages of small volume,high field strength,and compact stray field,the Halbach array magnet is of great potential in desktop NMR applications.However,field inhomogeneity poses a main obstacle to its applications.Active shimming is necessary for improving the field homogeneity.An active shim coil design method for cylindrical Halbach magnet based on inverse boundary element method(iBEM)is introduced in this work.Shim coils targeting 1st~3rd and Z4/Z5/Z6 spherical harmonic(SH)terms were designed with constraints of field accuracy,resistance,inductance,and current density.Wire loops and symmetric property influence were discussed to further improve the performance of high-order shim coils.Finally,with the prototype of the shim coils constructed,field pattern and SH transformation proved that the coils designed could fit the target SH distribution,though contamination from low-order components existed in highorder terms.A practical shimming experiment on the Halbach magnet has improved the homogeneity from 40.3 ppm to 3.8 ppm in radius 2.5 mm,height 5 mm cylindrical sample space,verifying the coils'compensation ability.This work provides a flexible inverse coil design method for cylindrical Halbach magnet and discusses the high-order shim coil design and implementation,which is potential in nuclear magnetic resonance applications based on Halbach magnet arrays. | Yajie Xu Feng Wang Ya Wang Peng Yu Jingzhong Zhang Xiaodong Yang | 2022 | Magnetic Resonance Letters2022，2，3： | 1 |
| 8 | Utilizing 3D DOSY NMR in the characterization of organic compounds in coal chemical wastewater显示文摘Coal chemical wastewater(CCW)with the features of high toxicity and poor biodegradability is a big issue in environmental remediation,posing a great threat to aquatic ecosystems and to human beings.Such complex molecular mixtures are notoriously difficult to characterize without initial physical separation.Herein,we present the 3D diffusion ordered spectroscopy(DOSY)analysis for CCW using DOSY-COSY and DOSY-HSQC methods,the advantages of this strategy have been demonstrated in the analysis of mixtures of aliphatic oxygenates and aromatic compounds,before being implemented on a genuine CCW sample in this study.The results showed that 3D DOSY is a robust and reliable tool for providing superior resolution and virtual separation of complex pollutants,and can be used as a general approach for structural elucidation. | Hui Ma Christian M.Pedersen Qi Zhao Shiyu Jia Bin Yuan Xianglin Hou Yingxiong Wang | 2022 | Magnetic Resonance Letters2022，2，2： | 1 |
| 9 | Study on the synthesis of spin labeled poly(styrene-co-maleic acid)s and their segmental motion显示文摘Study of the segmental mobility of polymer chains is important when the polymer is used as drag reduction agents of crude oil.Electron spin resonance(ESR)spectroscopy can provide important information about segmental dynamics of polymer chains,which is related to their microenvironment.In this article,we employed an amphiphilic polymer to study the effect of hydrophilic/hydrophobic balance of the polymers on the segmental motion of polymer chains.Poly(styrene-co-maleic acid)(PSMA)was spin labeled with 4-amino TEMPO radicals by increasing the concentration of radical moiety on the polymer chains.The PSMA and spin labeled-PSMAs(SL-PSMAs)were characterized by nuclear magnetic resonance(NMR),Fourier transform infrared(FT-IR)spectroscopy,Cyclic voltammetry(CV)and ESR techniques.Inter-polymer complexes(IPCs)of SL-PSMA-2 were prepared by employing polyethylene glycols(PEGs)of varying molecular weights.The results showed that the increased hydrophobic interactions of nitroxide radicals on the SLPSMAs’chains reduced the rotational mobility of spin labels and the random coil-toglobular transition of polymer chains occurred at higher pH value for SL-PSMAs,which showed a slow motion component in the ESR spectra of SL-PSMAs.Further,by increasing the molecular weight of PEGs in IPCs the complexation was increased,which also reduced the rotational motion of spin labels due to interpolymer hydrogen bonding causing a slow motion component in the ESR spectra.©2021 The Authors. | Kaleem-Ur-Rahman Naveed Li Wang Haojie Yu Qian Zhang Wei Xiong Raja Summe Ullah Ahsan Nazir Muhammad Usman Shah Fahad Amin Khan Md Alim Uddin Di Shen | 2022 | Magnetic Resonance Letters2022，2，2： | 1 |
| 10 | NMR used to study the side-reactions between peroxides and antioxidants during the reactive extrusion process of the impact polypropylene显示文摘Side reaction pathways are observed to occur between antioxidants and peroxide during the processing of multiple resin grades mediated by controlled peroxide-induced degradation of impact polypropylene.In the present work,the reaction mechanism and main by-products between antioxidants and peroxides were investigated.The results demonstrate that peroxides greatly accelerate the decomposition reactions,and the free radicals formed from peroxide decomposition react with,for example,the antioxidant AO1010 to produce dehydrogenation of phenyl propionic unit(s)at the a position(cinnamic acid ester moiety),which generates a conjugated system leading to the increased color of the product.It is the first time to confirm the cinnamic acid moiety's existence and report its NMR data.Further,this work confirms the dehydrogenation mechanism by comparison with different sterically hindered phenolic antioxidants.It also systematically summarizes the oxidation and degradation mechanism of AO168 and AO1010 under air and peroxide environments,respectively.Based on present study,clear guidelines are obtained to improve the quality of polymeric products,especially the appearance and stability,during product development. | Chunfa Li Ting Huang Yubin Bao Zhe Chen Guangxin Lin | 2022 | Magnetic Resonance Letters2022，2，2： | 1 |
| 11 | Mechanisms of antimicrobial peptides as characterized by solid-state NMR显示文摘Antimicrobial peptides(AMP)are small proteins that play critical roles in host defense against microbe invasion.Many AMPs disrupt the cellular membrane of microbe,while the mechanism of action of AMPs can be very sophisticated.Solid-state NMR(SSNMR)technique is powerful in characterizing the mechanism of AMPs in vivo and in vitro.This review summarizes the recent advance of SSNMR technique in AMP mechanisms characterization.We highlight the sample preparation approaches,the SSNMR spectroscopic methods,and a number of outstanding examples of AMP mechanisms elucidated via SSNMR spectroscopy. | Rong Han Shenlin Wang | 2022 | Magnetic Resonance Letters2022，2，2： | 1 |
| 12 | Probe-assisted NMR:Recent progress on the surface study of crystalline metal oxides with various terminated facets显示文摘The development of metal oxides with specific facet exposure for better catalytic performance in targeted applications has been well-documented.However,the understanding of surface structure-activity correlation is severely hindered by the current poor resolution of conventional surface characterization tools.In this mini-review,some of the latest research developments on the characterization of the surface structure and properties of faceted ZnO and TiO_(2)by probe-assisted nuclear magnetic resonance spectroscopy(NMR)are discussed. | Yung-Kang Peng Shik-chi Edman Tsang | 2022 | Magnetic Resonance Letters2022，2，1： | 1 |
| 13 | Application of ammonia probe-assisted solid-state NMR technique in zeolites and catalysis显示文摘Solid-state NMR(ssNMR)spectroscopy is a powerful technique for characterizing the surface sites of solid acids and organic intermediates formed during the acid catalyzed reaction.As a very useful probe molecule,ammonia is often utilized to determine the density of solidacids’surface sites by ssNMR spectroscopy.The present mini-review summarizes some of the latest research developments on the quantitative characterization of the acid sites and carbenium ions during the zeolite catalytic reaction by ammonia probe-assisted ssNMR spectroscopy. | Chang Wang Weili Dai Guangjun Wu Naijia Guan Landong Li | 2022 | Magnetic Resonance Letters2022，2，1： | 1 |
| 14 | Solid-state NMR studies of sulfonated SBA-15 and the synergistic catalysis of fructose into 5-hydroxymethylfurfural with dimethyl sulfoxide显示文摘Sulfonic acid functionalized mesoporous SBA-15 was prepared using the grafting method.The structure and acid properties were comprehensively characterized using multi-nuclear and quantitative probe molecule solid-state NMR(SSNMR),together with powder X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM),N2 adsorption-desorption techniques.Its catalytic performance in the conversion of fructose to 5-hydroxymethylfurfural(HMF)in dimethyl sulfoxide(DMSO)was studied.Catalyst dosage,reaction time,reaction temperature and solvent effect have been investigated.A high yield of HMF up to 93%was obtained at a relatively low temperature of 373 K for 180 min.The Brønsted acid of SBA-15_SO3H together with the solvent DMSO was found to synergistically catalyze the reaction.The catalyst preserved most of its activity after five times reuse and the catalytic activity can be recovered by H2O2 process. | Xin Li Wanling Shen Han Sun | 2022 | Magnetic Resonance Letters2022，2，1： | 1 |
| 15 | Regulation of MRI contrast and cellular retention time by cellular interfacial distribution of Gd agents:Implications for stem cell tracking显示文摘Human mesenchymal stem cells(hMSCs)were labeled with Dotarem or(Gd-DOTA)2-EM7(EM7Gd2)via electroporation(EP).Cellular transmission electron microscopy(TEM)reveals free distribution of Gd agents and formation of EM7Gd2 clusters in the cytosol.Cellular magnetic resonance imaging(MRI)reveals that the free Gd agents induce MRI signal enhancement effect due to its fast exocytosis and subsequent interaction with intercellular water molecules.The EM7Gd2 clusters exhibits a longer intracellular retention time and induce a persistent MRI signal reduction effect.The cellular MRI results are interpreted by taking into account both T1 and T2 relaxation rates and their correlation with cellular binding structures of Dotarem and EM7Gd2. | Yanhui Zhang Binbin Li Bo Tan Hailu Zhang Zongwu Deng | 2022 | Magnetic Resonance Letters2022，2，1： | 1 |
| 16 | Two open metal sites on the same metal: Dynamics of CO_(2) in MOF UTSA-74--Dedicated to Professor Xiuwen Han on the occasion of her 80th birthday显示文摘Metal-organic frameworks(MOFs)are an emerging dass of porous materials with many unique properties that make them promising candidates for carbon dioxide(CO_(2))capture and storage.A better understanding of the behavior of CO_(2) adsorbed inside MOF will enable researchers to develop the ability of designing new MOF based materials with high CO_(2) adsorption capabilities.It is well known that presence of open metal sites(OMSs)can greatly enhance the gas adsorption capability of MOFs.MOF UTSA-74,a framework isomer of well-known MOF-74 has a unique feature that upon activation,a single metal ion has two OMSs.Therefore,it presents a unique opportunity to probe the dynamics of CO_(2) molecules adsorbed on these OMSs.In this work,the CO_(2) adsorptive properties of MOF UTSA-74 are examined with particular attention being paid to the dynamics of the CO_(2) adsorbed on these OMSs.Specifically,variable temperature 13C static solid-state nuclear magnetic resonance(SSNMR)experiments were conducted to directly monitor the behavior of BCO_(2) in UTSA-74 at different loadings.All CO_(2) molecules undergo localized wobbling.At low loadings,some CO_(2) molecules jump among three OMSs from three different Zn atoms in the cOsS section of the channel.Others hop back and forth between the two neighboring OMSs.At high loading,the three site jump has ceased,but two-site hopping persists.The dynamical behavior of CO_(2) in UTSA-74 results from the unique Zn coord ination environment It was discovered that CO_(2) is less mobile in UTSA-74 than in its.framework isomer,MOF-74-Zn. | Yingxian Li Wanli Zhang Yining Huang | 2021 | Magnetic Resonance Letters2021，1，2： | 1 |
| 17 | NMR signal separation of ionic liquids by poly( sodium-p-styrenesulfonate)-assisted chromatographic NMR spectroscopy--Dedicated to Professor Xiuwen Han on the occasion of her 80th birthday显示文摘Diffusion-ordered nuclear magnetic resonance spectroscopy(DOSY),dubbed chromato-graphic NMR spectroscopy,can be used to simultaneously distinguish and identify the structures of components in a mixture according to their different diffusion coefficients.In order to improve the resolution of DOSY on the diffusion dimension,a lot of matrices have been developed to expand the application of this technique in mixture analysis.However,there is no matrix to detect the mixture of ionic liquids(ILs).Herein,we introduced a new matrix,poly(sodium-p-styrenesulfonate)(PSSNa),which can be used to fully separate the signals of a mixture of different ILs.The mixture of three imidazolium ILs of 1-butyl-3-methylimidazolium bromide,1-allyl-3-vinylimidazolium bromide and 1-arboxymethy-3-methylimidazolium chloride could be fully distinguished by virtue of their different interactions with PSSNa.We also investigated the influences of PSSNa amount,IL con-centration and solution pH value on the signal resolution of mixtures.This work provides a scientific reference for the analysis of the other IL analytes. | Kui Yan Zhengwu Bai Shaohua Huang | 2021 | Magnetic Resonance Letters2021，1，2： | 1 |
| 18 | The NMR core analyzing tomograph:a multi-functional tool for non-destructive testing of building materials显示文摘NMR is becoming increasingly popular for the investigation of building materials as it is a non-invasive technology that does not require any sample preparation nor causes damage to the material.Depending on the specific application it can offer insights into properties like porosity and spatial saturation degree as well as pore structure.Moreover it enables the determination of moisture transport properties and the(re-)distribution of internal moisture into different reservoirs or chemical phases upon damage and curing.However,as yet most investigations were carried out using devices originally either designed for geophysical applications or the analysis of rather homogeneous small scale(<10 mL)samples.This paper describes the capabilities of an NMR tomograph,which has been specifically optimized for the investigation of larger,heterogeneous building material samples(diameters of up to 72 mm,length of up to 700 mm)with a high flexibility due to interchangeable coils allowing for a high SNR and short echo times(50-80 ms). | Sabine Kruschwitz Sarah Munsch Melissa Telong Wolfram Schmidt Thilo Bintz Matthias Fladt Ludwig Stelzner | 2023 | Magnetic Resonance Letters2023，3，3： | 0 |
| 19 | Dipolar NMR relaxation of adsorbates on surfaces of controlled wettability显示文摘In reservoir rocks,the term“ageing”refers to extended exposition to crude oil;a typically water-wet sandstone will then gradually become oil-wet as a consequence of the deposition of insoluble fractions of oil onto the surface grains.Rocks have been aged artificially by subjecting them to a bitumen solution at elevated temperature in order to achieve comparable surface properties for three different types of rock:Bentheimer,Berea Buff and Liege Chalk.Using saturated and aromatic model compounds as proxies for crude oil,the nuclear magnetic resonance(NMR)relaxation dispersion in native and aged rocks was compared and correlated to the properties of paramagnetic impurities in these rock types.Perfluorated liquids were found to follow the same trend as deuterated and naturally occurring oil components,suggesting they can be used as suitable tracers for wettability studies since the ^(19)F nucleus is absent in natural sources.By combining electron paramagnetic resonance(EPR)and dynamic nuclear polarization(DNP)it becomes possible to identify and quantify the origin of the dominating relaxation processes between native and aged rocks,providing an alternative approach to assess wettability in natural rocks. | Siegfried Stapf Igor Shikhov Christoph Arns Bulat Gizatullin Carlos Mattea | 2023 | Magnetic Resonance Letters2023，3，3： | 0 |
| 20 | On the sampling strategies and models for measuring diffusion exchange with a double diffusion encoding sequence显示文摘Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging(dMRI).Many analysis frameworks using dMRI data have been proposed to describe exchange,often using a double diffusion encoding(DDE)stimulated echo sequence.Techniques such as diffusion exchange weighted imaging(DEWI)and the filter exchange and rapid exchange models,use a specific subset of the full space DDE signal.In this work,a general representation of the DDE signal was employed with different sampling schemes(namely constant b1,diagonal and anti-diagonal)from the data reduction models to estimate exchange.A near-uniform sampling scheme was proposed and compared with the other sampling schemes.The filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling schemes.These subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR scanner.In synthetic data,the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground truth.In experimental data,the shifted diagonal and near-uniform sampling schemes outperformed the others,yielding the most consistent estimates with the full space estimation.The results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling schemes.In future studies,algorithms could be further developed for the optimization of sampling schemes,as well as incorporating additional properties,such as geometry and diffusion anisotropy,into exchange frameworks. | Alfredo Ordinola Shan Cai Peter Lundberg Ruiliang Bai Evren Ozarslan | 2023 | Magnetic Resonance Letters2023，3，3： | 0 |
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