Magnetic Resonance Letters最新文献

{"title":"A review of functional MRI application for brain research of Chinese language processing","authors":"Jianqiao Ge ,&nbsp;Jia-Hong Gao","doi":"10.1016/j.mrl.2022.12.001","DOIUrl":"10.1016/j.mrl.2022.12.001","url":null,"abstract":"<div><p>As one of the most widely used languages in the world, Chinese language is distinct from most western languages in many properties, thus providing a unique opportunity for understanding the brain basis of human language and cognition. In recent years, non-invasive neuroimaging techniques such as magnetic resonance imaging (MRI) blaze a new trail to comprehensively study specific neural correlates of Chinese language processing and Chinese speakers. We reviewed the application of functional MRI (fMRI) in such studies and some essential findings on brain systems in processing Chinese. Specifically, for example, the application of task fMRI and resting-state fMRI in observing the process of reading and writing the logographic characters and producing or listening to the tonal speech. Elementary cognitive neuroscience and several potential research directions around brain and Chinese language were discussed, which may be informative for future research.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"3 1","pages":"Pages 1-13"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42321938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The study of electrochemical cycle for LiCoO2 by dual-mode EPR","authors":"Bei Hu,&nbsp;Fushan Geng,&nbsp;Ming Shen,&nbsp;Bingwen Hu","doi":"10.1016/j.mrl.2022.04.002","DOIUrl":"10.1016/j.mrl.2022.04.002","url":null,"abstract":"<div><p>Dual-mode electron paramagnetic resonance (EPR) spectroscopy was employed to analyze redox mechanisms in lithium cobalt oxide LiCoO₂ (LCO) cathode material during delithiation and lithiation. It was found that the O3-II could not fully convert back to the pristine O3–I phase while oxygen vacancies quickly generate and accumulate during the cycling. Our study paves the way for better understanding the doping effects of different elements on LiCoO₂ in the future.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"3 1","pages":"Pages 61-66"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46373007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent advances on surface metal hydrides studied by solid-state nuclear magnetic resonance spectroscopy","authors":"Pan Gao,&nbsp;Guangjin Hou","doi":"10.1016/j.mrl.2022.09.001","DOIUrl":"10.1016/j.mrl.2022.09.001","url":null,"abstract":"<div><p>Metal hydrides (M–H) on solid surfaces, i.e., surface M–H, are ubiquitous but critical species in heterogeneous catalysis, and their intermediate roles have been proposed in numerous reactions such as (de)hydrogenation and alkanes activation, etc., however, the detailed spectroscopic characterizations remain challenging. Solid-state nuclear magnetic resonance (ssNMR) spectroscopy has become a powerful tool in surface studies, as it provides access to local structural characterizations at atomic level from multiple views, with comprehensive information on chemical bonding and spatial structures. In this review, we summarized and discussed the latest research developments on the successful application of ssNMR to characterize surface M–H species on solid catalysts including supported single-site heterogeneous catalysts, bulk metal oxides and metal-modified zeolites. We also discussed the opportunities and challenges in this field, as well as the potential application/development of state-of-the-art ssNMR technologies to enable further exploration of metal hydrides in heterogeneous catalysis.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"3 1","pages":"Pages 31-42"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47151402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Consideration of transmembrane water exchange in pharmacokinetic model significantly improves the accuracy of DCE-MRI in estimating cellular density: A pilot study in glioblastoma multiforme","authors":"Zhenfeng Pang ,&nbsp;Zejun Wang ,&nbsp;Bao Wang ,&nbsp;Kaiyue Guo ,&nbsp;Cheng Meng ,&nbsp;Yingchao Liu ,&nbsp;Xueqian Kong ,&nbsp;Ruiliang Bai","doi":"10.1016/j.mrl.2022.04.001","DOIUrl":"10.1016/j.mrl.2022.04.001","url":null,"abstract":"<div><p>Transmembrane water exchange (TWE) including transcytolemmal water exchange and transvascular water exchange is involved in many <em>in vivo</em> measurements and makes different contributions to the measuring results. In this study, we focus on the potential influence of TWE on the cell density parameter, intracellular water mole fraction <em>p</em>_i, derived by dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) which has been reported as a technique to characterize perfusion and vascularization of tissues, but its accuracy in measuring cell density (or interstitial space) has been questioned. Sixteen patients with glioblastoma multiforme (GBM) were enrolled since GBM shows strong intratumor heterogeneity in both cell density and TWE. All the subjects were collected with DCE-MRI and apparent diffusion coefficient (ADC) map. The latter was considered as a valid surrogate of cell density. Extended Tofts (eTofts) model considering TWE as infinitely large variables and shutter-speed model (SSM) considering TWE as finite ones were used to fit DCE-MRI data. Monte Carlo (MC) and finite difference (FD) methods were used to simulate the influence of TWE on DCE-MRI-derived <em>p</em>_i and ADC, respectively. The eTofts model shows a significant overestimation of <em>p</em>_i in comparison with SSM in GBM (<em>P</em> &lt; 0.001), which is in accordance with MC simulations, and this overestimation shows dependence on the intra-to-extracellular water exchange rate constant (<em>k</em>_io). Significant negative correlations between ADC and SSM-derived <em>p</em>_i were found in both voxel-wise analyses (<em>t</em>-test <em>P</em> &lt; 0.001, average <em>r</em> = −0.74) and inter-subject comparisons (<em>r</em> = −0.63, <em>P</em> = 0.009). But no consistent voxel-wise correlations (<em>P</em> &gt; 0.05) and a weaker inter-subject negative correlation (<em>r</em> = −0.56, <em>P</em> = 0.02) were found between ADC and eTofts-derived <em>p</em>_i. Further experimental and FD results revealed that <em>k</em>_io made a limited contribution to ADC values in the physiological <em>k</em>_io range in GBM, supporting ADC as a valid biomarker of cell density. These results suggest that the DCE-MRI pharmacokinetic shutter-speed model could significantly improve its accuracy in cell density estimation because of the considering transmembrane water exchange.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 243-254"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000171/pdfft?md5=05375a3ddca565e25a128274217de040&pid=1-s2.0-S2772516222000171-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42268531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR assisted studies on the solution structures and functions of antimicrobial peptides","authors":"Yaying Zhang ,&nbsp;Chunyang Cao","doi":"10.1016/j.mrl.2022.08.001","DOIUrl":"10.1016/j.mrl.2022.08.001","url":null,"abstract":"<div><p>Microbial resistance has now become a global public health concern, and the spread of multidrug-resistant bacteria also threatens human health. Antimicrobial peptides (AMPs) are a class of small peptides with antibacterial, anti-inflammatory, anti-infective, anti-oxidation, anti-tumor, antiviral functions and immune regulation activities. Due to the small sizes, their structures are easily studied by nuclear magnetic resonance (NMR) techniques. Compared to traditional antibiotics, AMPs have specific antibacterial mechanisms, and do not easily result in the production of drug-resistant strains. Thus, the development of new antimicrobial peptides and their wide use instead of chemical antibiotics are of great significance to human health. In this review, we first summarized the relationship between the structures and functions of antimicrobial peptides. Then, we focused on examples, cathelicidins, a group of cationic antimicrobial peptides with multiple biological activities. Especially, cathelicidin BF30 or BF34, composed of 30 or 34 amino acids, were from the venom glands of the <em>Bungarus fasciatus</em> snake and were considered to be the most active antibacterial peptides among different cathelicidin members. Their solution structures determined by NMR are α-helixes, which are useful in designing new and stable peptides with similar framework, including stapple peptides by inducing chemical modifications in the sidechains of some residues, as well as cyclic peptides by inducing disulfide bond between cysteines in the sequences.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 214-223"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000390/pdfft?md5=bab8a2bdc69737c0febcf086775489b4&pid=1-s2.0-S2772516222000390-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44801701","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":"Heteronuclear-filtered 1H homonuclear multi-quantum correlation experiment at 100 kHz magic-angle spinning","authors":"Mingji Zheng ,&nbsp;Shuangqin Zeng ,&nbsp;Xiumei Wang ,&nbsp;Xiuzhi Gao ,&nbsp;Qiang Wang ,&nbsp;Jun Xu ,&nbsp;Feng Deng","doi":"10.1016/j.mrl.2022.09.002","DOIUrl":"10.1016/j.mrl.2022.09.002","url":null,"abstract":"<div><p>Remarkable advances in fast magic-angle spinning (MAS) techniques significantly improve the resolution of ¹H solid-state nuclear magnetic resonance (NMR) spectra. Here, we introduce a heteronuclear-filtered ¹H homonuclear multi-quantum (MQ) correlation strategy available at a MAS rate of 100 kHz by combining ¹H{X} heteronuclear-filtered methods and ¹H homonuclear MQ correlation experiments. The proposed strategy was applied to selectively extract ¹H signals of aluminum lactate (Al-Lac) in a mixture of Al-Lac and zinc lactate (Zn-Lac) using ²⁷Al-filtered methods (i.e., ¹H{²⁷Al} heteronuclear multiple quantum correlation (HMQC) or ¹H{²⁷Al} symmetry-based resonance-echo saturation-pulse double-resonance (S-RESPDOR)). We demonstrate that incorporating these ²⁷Al-filtered methods into two-dimensional (2D) ¹H–¹H double-quantum (DQ)/single-quantum (SQ), triple-quantum (TQ)/SQ, and even three-dimensional (3D) ²⁷Al/¹H(DQ)/¹H(SQ) experiments can facilitate the acquisition of spectra without signal overlap and targeted characterization of the ¹H species surrounding ²⁷Al sites. The proposed strategy is considered to efficiently extract key structural information from complex spin systems.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 266-275"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000420/pdfft?md5=3f3d17d187252f9384b47e72062131e2&pid=1-s2.0-S2772516222000420-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45934650","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":"Ringing cancellation in Carr-Purcell-Meiboom-Gill-type sequences","authors":"Shin Utsuzawa ,&nbsp;Marcus Donaldson ,&nbsp;Yi-Qiao Song","doi":"10.1016/j.mrl.2022.03.002","DOIUrl":"10.1016/j.mrl.2022.03.002","url":null,"abstract":"<div><p>We propose a four-step phase cycling scheme that can cancel ringings from both the excitation and the refocusing pulses in Carr-Purcell-Meiboom-Gill (CPMG) measurements. It allows accurate measurements of the first echo with short echo spacing <em>t</em>_E, yielding improved precision of porosity, permeability, and fluid type identification in porous media study, at a cost of ∼25% signal reduction. In our example, we achieved <em>t</em>_E = 100 μs on a 6.8 MHz unilateral NMR sensor without using a Q-switch. These methods can be integrated in all nuclear magnetic resonance (NMR) protocols using CPMG, such as relaxation (<em>T</em>₁, <em>T</em>₂) and diffusion measurements, and do not require additional hardware (e.g., Q-switches) to cancel ringing (although it can be used with a Q-switch to further reduce residual ringing).</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 233-242"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277251622200016X/pdfft?md5=c059f3e98bf01a49601d85051916bf4f&pid=1-s2.0-S277251622200016X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45201625","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":"The parallel tetrameric DNA G-quadruplex formed by the two-repeat C9orf72 GGGGCC sequence in solution","authors":"Changdong Liu ,&nbsp;Bo Zhou ,&nbsp;Naining Xu ,&nbsp;Chun Po Fung ,&nbsp;Bing Yan ,&nbsp;Monica Ching Suen ,&nbsp;Zeguo Huang ,&nbsp;Guang Zhu","doi":"10.1016/j.mrl.2022.07.004","DOIUrl":"10.1016/j.mrl.2022.07.004","url":null,"abstract":"<div><p>The abnormal expansion of G-rich hexanucleotide repeat, GGGGCC (G4C2), in chromosome 9 open reading frame 72 (<em>C9orf72</em>) is known to be the prevailing genetic cause of two fatal degenerative neurological diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). It is well known that the DNA G4C2 repeat expansion with different lengths can form G-quadruplexes which affect gene transcription related to ALS/FTD, therefore it is crucial to understand DNA G4C2 G-quadruplex structures. Herein, by utilizing nuclear magnetic resonance (NMR) spectroscopy, we examined DNA G-quadruplex structure adopted by two G4C2 hexanucleotide repeats with an inosine substitution at position 4, d(G4C2)₂-I4. We show that d(G4C2)₂-I4 folds into an eight-layer parallel tetrameric G-quadruplex containing two parallel dimeric G-quadruplexes stacking together through π-π interaction via 5′-to-5′ mode in solution. Each dimeric G-quadruplex unit involves two propeller loops composed of two cytosine bases. This result is consistent with the observation in the crystal structure of d(G4C2)₂. Our work not only sheds light on the structural diversity of G-quadruplexes adopted by d(G4C2)_n but also provides a structural basis for drug design in treatment of ALS and FTD.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 196-204"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000389/pdfft?md5=8cca9854277d7406b5ca1df88bcaa775&pid=1-s2.0-S2772516222000389-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41778332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR and biochemical characterization of the interaction between FGFR1 juxtamembrane domain and phospholipids","authors":"Yunyan Li ,&nbsp;Yong Liu ,&nbsp;Huiqin Zhang ,&nbsp;Zhen Wang ,&nbsp;Maosen Ruan ,&nbsp;Jiarong Wang ,&nbsp;Jing Yang ,&nbsp;Bo Wu ,&nbsp;Junfeng Wang","doi":"10.1016/j.mrl.2022.07.002","DOIUrl":"10.1016/j.mrl.2022.07.002","url":null,"abstract":"<div><p>Fibroblast growth factor receptors (FGFRs) play an important role in the regulation of cell proliferation, migration and differentiation, while the juxtamembrane domain (JMD) of FGFRs is the key in mediating these transmembrane signal transduction processes. Here, we expressed and purified the JMD (398K-470R) of FGFR1 with the presence of transmembrane domain (377I-397Y). The results from nuclear magnetic resonance (NMR) chemical shift analysis demonstrate that the main structure of JMD is disordered. Yet, the N-terminus of JMD was observed to form a short α-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) into its membrane mimic bicelles. Moreover, the N-terminus of JMD interacts with FRS2α, which is a substrate 2α of FGFR. Hence, we propose a model that FGFR1-JMD may interact with FRS2α and negatively charged lipids competitively. Our study provides a new understanding on the role of the JMD of FGFRs.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 205-213"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000274/pdfft?md5=fe6259e165cab66398dc1a2c06a56580&pid=1-s2.0-S2772516222000274-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46074756","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":"Reduction and pH-responsive performance of nitroxide radical-containing copolymers probed by EPR spectroscopy","authors":"Md Alim Uddin,&nbsp;Haojie Yu,&nbsp;Li Wang","doi":"10.1016/j.mrl.2022.07.003","DOIUrl":"10.1016/j.mrl.2022.07.003","url":null,"abstract":"<div><p>Although stimuli-responsive polymers have appeared as promising materials for drug administration, the effectiveness of these materials on various bioinspired stimuli is still open for dispute. In this work, the stimuli-responsive behaviors of radical-containing nonamphiphilic copolymers were investigated using electron paramagnetic resonance (EPR) spectroscopy while altering the pH and reductant concentration. The concentration of radicals in the aqueous solution had a considerable impact on self-assembly. The nitroxide radicals (hydrophobic) were converted to hydroxylamine (hydrophilic) when ascorbic acid (Asc) was added as a reductant, and the assemblies were switched to dissolution with a rate control behavior. The behavior of morphological change was observed in the acidic pH due to the disproportionation reaction of nitroxide radicals forming cationic species. The acquired results give new insights into the colloidal nanoparticles of nonamphiphilic copolymers and encourage the development of comparable responsive nanoparticles with intriguing drug delivery applications.</p></div>","PeriodicalId":93594,"journal":{"name":"Magnetic Resonance Letters","volume":"2 4","pages":"Pages 255-265"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772516222000377/pdfft?md5=abb05d39e76fde95631c2a68bbd622d5&pid=1-s2.0-S2772516222000377-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46036503","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}