Journal of Magnetic Resonance Open最新文献_第10页

An introduction to one- and two-dimensional lineshape analysis of chemically exchanging systems 介绍化学交换体系的一维和二维线形分析

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2023-03-05 DOI: 10.1016/j.jmro.2023.100102

Christopher A. Waudby , Ignacio Alfonso

引用次数: 3

Perpetual hyperpolarization of allyl acetate from parahydrogen and continuous flow heterogeneous hydrogenation with recycling of unreacted propargyl acetate 对氢催化醋酸丙烯酯的永久超极化和未反应醋酸丙酯的连续流动非均相加氢

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100076

Tommy Yunpu Zhao , Michelle P. Lapak , Ranjan Behera , Hanqin Zhao , Maria-Jose Ferrer , Helena E. Hagelin Weaver , Wenyu Huang , Clifford R. Bowers

{"title":"Perpetual hyperpolarization of allyl acetate from parahydrogen and continuous flow heterogeneous hydrogenation with recycling of unreacted propargyl acetate","authors":"Tommy Yunpu Zhao , Michelle P. Lapak , Ranjan Behera , Hanqin Zhao , Maria-Jose Ferrer , Helena E. Hagelin Weaver , Wenyu Huang , Clifford R. Bowers","doi":"10.1016/j.jmro.2022.100076","DOIUrl":"https://doi.org/10.1016/j.jmro.2022.100076","url":null,"abstract":"<div>A novel closed loop, continuous flow (CF) reactor system for parahydrogen enhanced nuclear magnetic resonance (NMR) of liquids via heterogeneous catalysis is introduced which enables recycling of unreacted liquid substrate reactant. This system consists of an HPLC pump, a liquid substrate reservoir incorporating a gas diffuser, an all-metal packed bed catalytic reactor, and an AF-2400 tube-in-tube gas permeable membrane for removal of normal H2. Two types of supported metal nanoparticle catalysts were tested: mesoporous silica encapsulated Pt3Sn intermetallic nanoparticles and a Rh on anatase TiO2 support. In the CF hydrogenation of propargyl acetate to allyl acetate, the hyperpolarized signals exhibited stability over 20 min of recirculation, with signal enhancements of up to 626 using 99% p-H2 and negligible leaching of the catalyst into the flowing solutions. These results demonstrate the practicality of performing systematic optimization of conditions for continuous flow catalysis and polarization transfer to heteronuclei with important implications for biomedical magnetic resonance imaging.</div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"12 ","pages":"Article 100076"},"PeriodicalIF":2.624,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826384","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}

引用次数: 2

1H and 19F NMR chemical shifts for hydrogen bond strength determination: Correlations between experimental and computed values 氢键强度测定的1H和19F核磁共振化学位移:实验值和计算值之间的相关性

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100070

Claudio Dalvit , Marina Veronesi , Anna Vulpetti

引用次数: 2

Spatially encoded polarization transfer for improving the quantitative aspect of 1H–13C HSQC 提高1H-13C HSQC定量方面的空间编码极化转移

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100063

Bikash Baishya , Rajeev Verma , Rashmi Parihar

{"title":"Spatially encoded polarization transfer for improving the quantitative aspect of 1H–13C HSQC","authors":"Bikash Baishya , Rajeev Verma , Rashmi Parihar","doi":"10.1016/j.jmro.2022.100063","DOIUrl":"https://doi.org/10.1016/j.jmro.2022.100063","url":null,"abstract":"<div>Peak overlap hampers quantification in one-dimensional (1D) 1H NMR. 2D 1H -13C HSQC spectrum provides resolution superior to 1D 1H NMR. However, quantifying the components in a complex mixture with HSQC is not straightforward as in 1D 1H NMR. Quantification using HSQC could open up new avenues for studying metabolism. The variations in 1H–13C scalar couplings, T1, T2, and pulse imperfections contribute to this problem. Although T1 and T2 can be suitably chosen to minimize their deleterious effects, the differential polarization transfer for different resonances owing to large variations in 1H -13C couplings does not allow the cross-peak intensities to be directly correlated to the quantity of metabolites. Existing approaches are time-consuming. We show that spatial encoding of the polarization transfer delays in HSQC using sweep frequency pulses in the presence of a magnetic field gradient allows one to have a transfer of polarization from 1H to 13C insensitive to variations in 1H -13C couplings improving the quantitative aspect of HSQC. Comparisons to other QHSQC and perfected HSQC variants are also provided.</div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"12 ","pages":"Article 100063"},"PeriodicalIF":2.624,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826381","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}

引用次数: 1

Influence of stereoelectronic interactions on the 13C NMR chemical shift in iodine-containing molecules 立体电子相互作用对含碘分子13C核磁共振化学位移的影响

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100080

Renan V. Viesser , Cláudio F. Tormena

引用次数: 0

Revisiting dipolar relaxation of a homonuclear spin pair in the presence of a radio frequency field: A tutorial 在射频场存在下重访同核自旋对的偶极弛豫:教程

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100065

Yuki Toyama , Lewis E. Kay

{"title":"Revisiting dipolar relaxation of a homonuclear spin pair in the presence of a radio frequency field: A tutorial","authors":"Yuki Toyama , Lewis E. Kay","doi":"10.1016/j.jmro.2022.100065","DOIUrl":"https://doi.org/10.1016/j.jmro.2022.100065","url":null,"abstract":"<div>NMR studies exploit spin relaxation in a multitude of different ways, providing information on molecular structure and dynamics. Calculating the relaxation rates of NMR active nuclei in multi-spin systems is often a prerequisite for the proper analysis of experimental data. For many researchers the calculations appear complex, often involving different basis sets or expressions describing relaxation in different frames. In this tutorial paper we derive expressions for dipolar relaxation of an I-S two spin spin-system in the presence of a B1 radio frequency field, where spins I and S can be either like or unlike. We consider two different approaches for the derivation of relaxation elements that have been used in the literature, including one where a series of transformations are carried out to the interaction representation of the effective field, comprising B1 and Zeeman components. A second procedure is based on the well-known Solomon equations. We show that both approaches lead to identical results, in the process presenting a pedagogical description of relaxation theory.</div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"12 ","pages":"Article 100065"},"PeriodicalIF":2.624,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3135449","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}

引用次数: 0

Frontiers of NMR 核磁共振前沿

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100071

Miquel Pons

引用次数: 0

The Konrat's Festschrift - Editorial 康拉特音乐节

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100078

Nicolas Coudevylle , Julien Orts , Georg Kontaxis

引用次数: 0

An all-at-once 2D CEST by F1-spatial frequency encoding 由f1空间频率编码的一次性二维CEST

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100073

Markus Rotzinger, Sebastian Tassoti, Klaus Zangger

引用次数: 0

Accurate analysis and perspectives for systematic design of magnetic resonance experiments using single-spin vector and exact effective Hamiltonian theory 基于单自旋矢量和精确有效哈密顿理论的磁共振实验系统设计的精确分析与展望

IF 2.624

Journal of Magnetic Resonance Open Pub Date : 2022-12-01 DOI: 10.1016/j.jmro.2022.100064

Anders B. Nielsen, Niels Chr. Nielsen

{"title":"Accurate analysis and perspectives for systematic design of magnetic resonance experiments using single-spin vector and exact effective Hamiltonian theory","authors":"Anders B. Nielsen, Niels Chr. Nielsen","doi":"10.1016/j.jmro.2022.100064","DOIUrl":"https://doi.org/10.1016/j.jmro.2022.100064","url":null,"abstract":"<div>Aimed at fundamental understanding and design of advanced magnetic resonance experiments on basis of Hamiltonians, we describe highly convergent and exact effective Hamiltonian methods which alleviate important deficits of current less accurate methods. This involves single-spin vector effective Hamiltonian theory (SSV-EHT) to first order in the interaction frame of rf and chemical shift offsets as well as exact effective Hamiltonian theory (EEHT) being an exact approach to average Hamiltonian theory not relying on interaction frame transformations. Bringing these methods together, we present tools to analyze challenging experiments in need of considering large static components in Hamiltonian (e.g., offsets) while economizing with radiofrequency irradiation power. It is demonstrated how the two complementary tools may provide important new insight into the detailed effective Hamiltonians of advanced NMR experiments, noting that the methods are by no means restricted to NMR. This is demonstrated for isotropic mixing in liquid-state NMR and dipolar recoupling in solid-state NMR where insight into the delicate interplay between bilinear two-spin and linear single-spin terms in the effective Hamiltonian may increase understanding of determinants for broadband excitation and the formation of recoupling resonances. Furthermore, we demonstrate how simple products single-spin effective Hamiltonians may be used as generators of multiple-spin effective Hamiltonians and though this a new approach to density operator calculations for large multiple-spin systems.</div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"12 ","pages":"Article 100064"},"PeriodicalIF":2.624,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3340430","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}

引用次数: 0