Magnetic Resonance in Chemistry最新文献_第9页

Anisotropic NMR data acquisition with a prototype 400 MHz cryogen-free NMR spectrometer 各向异性核磁共振数据采集与原型400兆赫无低温核磁共振光谱仪

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-08-02 DOI: 10.1002/mrc.5380

Maria Victoria Silva Elipe, Ikenna Edward Ndukwe, Armando Navarro-Vázquez

{"title":"Anisotropic NMR data acquisition with a prototype 400 MHz cryogen-free NMR spectrometer","authors":"Maria Victoria Silva Elipe, Ikenna Edward Ndukwe, Armando Navarro-Vázquez","doi":"10.1002/mrc.5380","DOIUrl":"10.1002/mrc.5380","url":null,"abstract":"High-temperature superconducting (HTS) materials have recently been incorporated into the construction of HTS cryogen-free magnets for nuclear magnetic resonance (NMR) spectroscopy. These HTS NMR spectrometers do not require liquid cryogens, thereby providing significant cost savings and facilitating easy integration into chemistry laboratories. However, the optimal performance of these HTS magnets against standard cryogen NMR magnets must be evaluated, especially with demanding modern NMR applications such as NMR in anisotropic media. The stability of the HTS magnets over time and their performance with complex pulse sequence experiments are the main unknown factors of this new technology. In this study, we evaluate the utility of our prototype 400 MHz cryogen-free power-driven HTS NMR spectrometer, installed in the fumehood of a chemistry laboratory, for stereochemical analysis of three commercial natural products (artemisinin, artemether, and dihydroartemisinin) via measurement of anisotropic NMR data, in particular, residual dipolar couplings. The accuracy of measurement of the anisotropic NMR data with the HTS magnet spectrometer is evaluated through the CASE-3D fitting protocol, as implemented in the Mestrenova-StereoFitter software program.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5380","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10531300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Automated nuclear magnetic resonance fingerprinting of mixtures 混合物的自动核磁共振指纹识别

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-29 DOI: 10.1002/mrc.5381

Thomas Specht, Justus Arweiler, Johannes Stüber, Kerstin Münnemann, Hans Hasse, Fabian Jirasek

{"title":"Automated nuclear magnetic resonance fingerprinting of mixtures","authors":"Thomas Specht, Justus Arweiler, Johannes Stüber, Kerstin Münnemann, Hans Hasse, Fabian Jirasek","doi":"10.1002/mrc.5381","DOIUrl":"10.1002/mrc.5381","url":null,"abstract":"Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for qualitative and quantitative analysis. However, for complex mixtures, determining the speciation from NMR spectra can be tedious and sometimes even unfeasible. On the other hand, identifying and quantifying structural groups in a mixture from NMR spectra is much easier than doing the same for components. We call this group-based approach “NMR fingerprinting.” In this work, we show that NMR fingerprinting can even be performed in an automated way, without expert knowledge, based only on standard NMR spectra, namely, 13C, 1H, and 13C DEPT NMR spectra. Our approach is based on the machine-learning method of support vector classification (SVC), which was trained here on thousands of labeled pure-component NMR spectra from open-source data banks. We demonstrate the applicability of the automated NMR fingerprinting using test mixtures, of which spectra were taken using a simple benchtop NMR spectrometer. The results from the NMR fingerprinting agree remarkably well with the ground truth, which was known from the gravimetric preparation of the samples. To facilitate the application of the method, we provide an interactive website (https://nmr-fingerprinting.de), where spectral information can be uploaded and which returns the NMR fingerprint. The NMR fingerprinting can be used in many ways, for example, for process monitoring or thermodynamic modeling using group-contribution methods—or simply as a first step in species analysis.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5381","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10040078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction to “Revisiting aliasing noise to build more robust sparsity in nonuniform sampling 2D-NMR” 修正“重新审视混叠噪声以在非均匀采样2D-NMR中建立更健壮的稀疏性”

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-24 DOI: 10.1002/mrc.5383

{"title":"Correction to “Revisiting aliasing noise to build more robust sparsity in nonuniform sampling 2D-NMR”","authors":"","doi":"10.1002/mrc.5383","DOIUrl":"10.1002/mrc.5383","url":null,"abstract":"\u0000 Cullen, L. E., Marchiori, A., Rovnyak, D., Magn Reson Chem 2023, 61(9-10), 337. https://doi.org/10.1002/mrc.5340Figure S1 The convolutional filter developed in this work is illustrated schematically and then applied to a conservative 50% NUS schedule (512/1024, quantile qsin x = 2, e = 2). In (a), the general algorithm is summarized where a given schedule is expanded and gaps are zero-filled, while integer values in the sampling schedule are set to 1; a short filter sequence constituting a repeating pattern is convolved across the NUS sampling schedule. Metrics developed to characterize the repeat sequences are the (b) convolutional score histogram (CSH), displaying convolutional scores for given repeat sequences, and (c) the repeat length curve (RLC) which demonstrates the lengths and frequencies of a single repeat type in a schedule. The example in this figure means that there are 14 isolated occurrences of the test sequence, and only one tract that has four consecutive instances of the filter sequence. Note: A prior version of the Supporting Information contained a typo in panel (a), which is corrected here.We apologize for this error.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5383","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10531275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Observing exocrine pancreas metabolism using a novel pancreas perfusion technique in combination with hyperpolarized [1-13C]pyruvate 使用新型胰腺灌注技术结合超极化[1-13C]丙酮酸盐观察胰腺外分泌代谢。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-22 DOI: 10.1002/mrc.5382

Anna Rushin, Marc A. McLeod, Mukundan Ragavan, Matthew E. Merritt

{"title":"Observing exocrine pancreas metabolism using a novel pancreas perfusion technique in combination with hyperpolarized [1-13C]pyruvate","authors":"Anna Rushin, Marc A. McLeod, Mukundan Ragavan, Matthew E. Merritt","doi":"10.1002/mrc.5382","DOIUrl":"10.1002/mrc.5382","url":null,"abstract":"In a clinical setting, ex vivo perfusions are routinely used to maintain and assess organ viability prior to transplants. Organ perfusions are also a model system to examine metabolic flux while retaining the local physiological structure, with significant success using hyperpolarized (HP) 13C NMR in this context. We use a novel exocrine pancreas perfusion technique via the common bile duct to assess acinar cell metabolism with HP [1-13C]pyruvate. The exocrine component of the pancreas produces digestive enzymes through the ductal system and is often neglected in research on the pancreas. Real-time production of [1-13C]lactate, [1-13C]alanine, [1-13C]malate, [4-13C]malate, [1-13C]aspartate, and H13CO3− was detected. The appearance of these resonances indicates flux through both pyruvate dehydrogenase and pyruvate carboxylase. We studied excised pancreata from C57BL/6J mice and NOD.Rag1−/−.AI4α/β mice, a commonly used model of Type 1 Diabetes (T1D). Pancreata from the T1D mice displayed increased lactate to alanine ratio without changes in oxygen consumption, signifying increased cytosolic NADH levels. The mass isotopologue analysis of the extracted pancreas tissue using gas chromatography–mass spectrometry revealed confirmatory 13C enrichment in multiple TCA cycle metabolites that are products of pyruvate carboxylation. The methodology presented here has the potential to provide insight into mechanisms underlying several pancreatic diseases, such as diabetes, pancreatitis, and pancreatic cancer.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9849315","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 nuclear magnetic resonance: Recent advances and applications 17O核磁共振：最新进展和应用

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-14 DOI: 10.1002/mrc.5378

Leonid B. Krivdin

引用次数: 0

Nuclear magnetic resonance-based structural elucidation of novel marine glycans and derived oligosaccharides 基于核磁共振的新型海洋聚糖和衍生低聚糖结构阐释

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-13 DOI: 10.1002/mrc.5377

Rohini Dwivedi, Antim K. Maurya, Hoda Ahmed, Marwa Farrag, Vitor H. Pomin

{"title":"Nuclear magnetic resonance-based structural elucidation of novel marine glycans and derived oligosaccharides","authors":"Rohini Dwivedi, Antim K. Maurya, Hoda Ahmed, Marwa Farrag, Vitor H. Pomin","doi":"10.1002/mrc.5377","DOIUrl":"10.1002/mrc.5377","url":null,"abstract":"Marine glycans of defined structures are unique representatives among all kinds of structurally complex glycans endowed with important biological actions. Besides their unique biological properties, these marine sugars also enable advanced structure–activity relationship (SAR) studies given their distinct and defined structures. However, the natural high molecular weights (MWs) of these marine polysaccharides, sometimes even bigger than 100 kDa, pose a problem in many biophysical and analytical studies. Hence, the preparation of low MW oligosaccharides becomes a strategy to overcome the problem. Regardless of the polymeric or oligomeric lengths of these molecules, structural elucidation is mandatory for SAR studies. For this, nuclear magnetic resonance (NMR) spectroscopy plays a pivotal role. Here, we revisit the NMR-based structural elucidation of a series of marine sulfated poly/oligosaccharides discovered in our laboratory within the last 2 years. This set of structures includes the α-glucan extracted from the bivalve Marcia hiantina; the two sulfated galactans extracted from the red alga Botryocladia occidentalis; the fucosylated chondroitin sulfate isolated from the sea cucumber Pentacta pygmaea; the oligosaccharides produced from the fucosylated chondroitin sulfates from this sea cucumber species and from another species, Holothuria floridana; and the sulfated fucan from this later species. Specific 1H and 13C chemical shifts, generated by various 1D and 2D homonuclear and heteronuclear NMR spectra, are exploited as the primary source of information in the structural elucidation of these marine glycans.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9776722","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

Contributions towards variable temperature shielding for compact NMR instruments 为小型核磁共振仪器的变温屏蔽做出贡献

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-07-12 DOI: 10.1002/mrc.5379

Martin Bornemann-Pfeiffer, Klas Meyer, Jeremy Lademann, Matthias Kraume, Michael Maiwald

{"title":"Contributions towards variable temperature shielding for compact NMR instruments","authors":"Martin Bornemann-Pfeiffer, Klas Meyer, Jeremy Lademann, Matthias Kraume, Michael Maiwald","doi":"10.1002/mrc.5379","DOIUrl":"10.1002/mrc.5379","url":null,"abstract":"The application of compact NMR instruments to hot flowing samples or exothermically reacting mixtures is limited by the temperature sensitivity of permanent magnets. Typically, such temperature effects directly influence the achievable magnetic field homogeneity and hence measurement quality. The internal-temperature control loop of the magnet and instruments is not designed for such temperature compensation. Passive insulation is restricted by the small dimensions within the magnet borehole. Here, we present a design approach for active heat shielding with the aim of variable temperature control of NMR samples for benchtop NMR instruments using a compressed airstream which is variable in flow and temperature. Based on the system identification and surface temperature measurements through thermography, a model predictive control was set up to minimise any disturbance effect on the permanent magnet from the probe or sample temperature. This methodology will facilitate the application of variable-temperature shielding and, therefore, extend the application of compact NMR instruments to flowing sample temperatures that differ from the magnet temperature.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5379","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9764291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

CAT on MOUSE: Control and automation of temperature for single-sided NMR instruments such as NMR-MOUSE CAT on MOUSE：单面 NMR 仪器（如 NMR-MOUSE）的温度控制和自动化

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-06-21 DOI: 10.1002/mrc.5376

Sarah Mailhiot, Otto Mankinen, Jing Li, Yashu Kharbanda, Ville-Veikko Telkki, Mateusz Urbańczyk

引用次数: 0

Structure elucidation of olasubscorpioside C, a new rotameric biflavonoid glycoside from the stem barks of Olax subscorpioidea (Oliv) 山茱萸(Olax subscorpioidea, Oliv)茎皮中一种新的轮状双黄酮苷的结构解析

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-06-21 DOI: 10.1002/mrc.5375

Bienvenu Tsakem, Billy Tchegnitegni Toussie, Xavier Siwe-Noundou, Beaudelaire Kemvoufo Ponou, Rémy Bertrand Teponno, Syed Ghulam Musharraf, Leon Azefack Tapondjou

引用次数: 0

Structural applications of the isotropic liquid-phase deuterium nuclear magnetic resonance 各向同性液相氘核磁共振的结构应用

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-06-21 DOI: 10.1002/mrc.5374

Leonid B. Krivdin

引用次数: 0