Irina Kandarakova, Stanislav Yakushkin, Nikolay Nesterov, Alexey Philippov, Oleg Martyanov
Highly dispersed Ni-TiO2 catalyst has been studied in the process of preparation and under catalytic transfer hydrogenation reaction conditions in supercritical 2-propanol (250°C, 70 bar) using electron spin resonance in situ. Electron spin resonance in situ has been used to study the process of the catalyst passivation and subsequent reduction of the oxide layer in the gas flow. Reduction of the NiO layer on the surface of passivated Ni nanoparticles has been detected in supercritical 2-propanol, which is in agreement with kinetic modeling data. It has been found that the reduction of the nickel oxide layer in supercritical 2-propanol occurs at a lower temperature compared with the reduction in hydrogen flow, according to in situ electron spin resonance study.
{"title":"Reactivation of Ni-TiO2 catalysts in hydrogen flow and in supercritical 2-propanol—Comparative study by electron spin resonance in situ","authors":"Irina Kandarakova, Stanislav Yakushkin, Nikolay Nesterov, Alexey Philippov, Oleg Martyanov","doi":"10.1002/mrc.5385","DOIUrl":"https://doi.org/10.1002/mrc.5385","url":null,"abstract":"<p>Highly dispersed Ni-TiO<sub>2</sub> catalyst has been studied in the process of preparation and under catalytic transfer hydrogenation reaction conditions in supercritical 2-propanol (250°C, 70 bar) using electron spin resonance in situ. Electron spin resonance in situ has been used to study the process of the catalyst passivation and subsequent reduction of the oxide layer in the gas flow. Reduction of the NiO layer on the surface of passivated Ni nanoparticles has been detected in supercritical 2-propanol, which is in agreement with kinetic modeling data. It has been found that the reduction of the nickel oxide layer in supercritical 2-propanol occurs at a lower temperature compared with the reduction in hydrogen flow, according to in situ electron spin resonance study.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 11","pages":"574-581"},"PeriodicalIF":2.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50125420","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}
Panteleimon G. Takis, Varvara A. Aggelidou, Caroline J. Sands, Alexandra Louka
One-dimensional (1D) proton-nuclear magnetic resonance (1H-NMR) spectroscopy is an established technique for the deconvolution of complex biological sample types via the identification/quantification of small molecules. It is highly reproducible and could be easily automated for small to large-scale bioanalytical, epidemiological, and in general metabolomics studies. However, chemical shift variability is a serious issue that must still be solved in order to fully automate metabolite identification. Herein, we demonstrate a strategy to increase the confidence in assignments and effectively predict the chemical shifts of various NMR signals based upon the simplest form of statistical models (i.e., linear regression). To build these models, we were guided by chemical homology in serum/plasma metabolites classes (i.e., amino acids and carboxylic acids) and similarity between chemical groups such as methyl protons. Our models, built on 940 serum samples and validated in an independent cohort of 1,052 plasma-EDTA spectra, were able to successfully predict the 1H NMR chemical shifts of 15 metabolites within ~1.5 linewidths (Δv1/2) error range on average. This pilot study demonstrates the potential of developing an algorithm for the accurate assignment of 1H NMR chemical shifts based solely on chemically defined constraints.
一维质子核磁共振(1h - nmr)波谱是一种成熟的技术,通过小分子的鉴定/定量来反褶积复杂的生物样品类型。它具有很高的可重复性,可以很容易地自动化用于小型到大规模的生物分析,流行病学和一般代谢组学研究。然而,为了使代谢物鉴定完全自动化,化学位移可变性仍然是一个必须解决的严重问题。在此,我们展示了一种策略,以增加分配的置信度,并基于最简单的统计模型(即线性回归)有效地预测各种核磁共振信号的化学位移。为了建立这些模型,我们以血清/血浆代谢物类别(即氨基酸和羧酸)的化学同源性和化学基团(如甲基质子)之间的相似性为指导。我们的模型建立在940份血清样本上,并在1052份血浆edta光谱的独立队列中进行了验证,能够成功预测15种代谢物的1 H NMR化学位移,平均误差范围为1.5线宽(Δv1/2)。这项初步研究表明,开发一种仅基于化学定义约束的1 H NMR化学位移精确分配算法的潜力。
{"title":"Mapping of 1H NMR chemical shifts relationship with chemical similarities for the acceleration of metabolic profiling: Application on blood products","authors":"Panteleimon G. Takis, Varvara A. Aggelidou, Caroline J. Sands, Alexandra Louka","doi":"10.1002/mrc.5392","DOIUrl":"10.1002/mrc.5392","url":null,"abstract":"<p>One-dimensional (1D) proton-nuclear magnetic resonance (<sup>1</sup>H-NMR) spectroscopy is an established technique for the deconvolution of complex biological sample types via the identification/quantification of small molecules. It is highly reproducible and could be easily automated for small to large-scale bioanalytical, epidemiological, and in general metabolomics studies. However, chemical shift variability is a serious issue that must still be solved in order to fully automate metabolite identification. Herein, we demonstrate a strategy to increase the confidence in assignments and effectively predict the chemical shifts of various NMR signals based upon the simplest form of statistical models (i.e., linear regression). To build these models, we were guided by chemical homology in serum/plasma metabolites classes (i.e., amino acids and carboxylic acids) and similarity between chemical groups such as methyl protons. Our models, built on 940 serum samples and validated in an independent cohort of 1,052 plasma-EDTA spectra, were able to successfully predict the <sup>1</sup>H NMR chemical shifts of 15 metabolites within ~1.5 linewidths (Δ<i>v</i><sub>1/2</sub>) error range on average. This pilot study demonstrates the potential of developing an algorithm for the accurate assignment of <sup>1</sup>H NMR chemical shifts based solely on chemically defined constraints.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 12","pages":"759-769"},"PeriodicalIF":2.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5392","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10210349","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}
Anna-Laura Hasubek, Xiaoyu Wang, Ella Zhang, Marta Kobus, Jiashang Chen, Lindsey A. Vandergrift, Annika Kurreck, Felix Ehret, Sarah Dinges, Annika Hohm, Marlon Tilgner, Alexander Buko, Piet Habbel, Johannes Nowak, Nathaniel D. Mercaldo, Andrew Gusev, Adam S. Feldman, Leo L. Cheng
Prostate cancer (PCa) is one of the most prevalent cancers in men worldwide. For its detection, serum prostate-specific antigen (PSA) screening is commonly used, despite its lack of specificity, high false positive rate, and inability to discriminate indolent from aggressive PCa. Following increases in serum PSA levels, clinicians often conduct prostate biopsies with or without advanced imaging. Nuclear magnetic resonance (NMR)-based metabolomics has proven to be promising for advancing early-detection and elucidation of disease progression, through the discovery and characterization of novel biomarkers. This retrospective study of urine-NMR samples, from prostate biopsy patients with and without PCa, identified several metabolites involved in energy metabolism, amino acid metabolism, and the hippuric acid pathway. Of note, lactate and hippurate—key metabolites involved in cellular proliferation and microbiome effects, respectively—were significantly altered, unveiling widespread metabolomic modifications associated with PCa development. These findings support urine metabolomics profiling as a promising strategy to identify new clinical biomarkers for PCa detection and diagnosis.
{"title":"Differentiation of patients with and without prostate cancer using urine 1H NMR metabolomics","authors":"Anna-Laura Hasubek, Xiaoyu Wang, Ella Zhang, Marta Kobus, Jiashang Chen, Lindsey A. Vandergrift, Annika Kurreck, Felix Ehret, Sarah Dinges, Annika Hohm, Marlon Tilgner, Alexander Buko, Piet Habbel, Johannes Nowak, Nathaniel D. Mercaldo, Andrew Gusev, Adam S. Feldman, Leo L. Cheng","doi":"10.1002/mrc.5391","DOIUrl":"10.1002/mrc.5391","url":null,"abstract":"<p>Prostate cancer (PCa) is one of the most prevalent cancers in men worldwide. For its detection, serum prostate-specific antigen (PSA) screening is commonly used, despite its lack of specificity, high false positive rate, and inability to discriminate indolent from aggressive PCa. Following increases in serum PSA levels, clinicians often conduct prostate biopsies with or without advanced imaging. Nuclear magnetic resonance (NMR)-based metabolomics has proven to be promising for advancing early-detection and elucidation of disease progression, through the discovery and characterization of novel biomarkers. This retrospective study of urine-NMR samples, from prostate biopsy patients with and without PCa, identified several metabolites involved in energy metabolism, amino acid metabolism, and the hippuric acid pathway. Of note, lactate and hippurate—key metabolites involved in cellular proliferation and microbiome effects, respectively—were significantly altered, unveiling widespread metabolomic modifications associated with PCa development. These findings support urine metabolomics profiling as a promising strategy to identify new clinical biomarkers for PCa detection and diagnosis.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 12","pages":"740-747"},"PeriodicalIF":2.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10502504","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}
Hydroxypropyl methylcellulose acetyl succinate (HPMCAS) is widely used as a pharmaceutical excipient, making a detailed understanding of its tunable structure important for formulation design. Several recently reported peak assignments in the solid-state 13C NMR spectrum of HPMCAS have been corrected here using peak integrals in quantitative spectra, spectral editing, empirical chemical-shift predictions based on solution NMR, and full spectrum simulation analogous to deconvolution. Unlike in cellulose, the strong peak at 84 ppm must be assigned to C2 and C3 methyl ethers, instead of regular C4 of cellulose. The proposed assignment of signals at <65 ppm to OCH sites, including C5 of cellulose, could not be confirmed. CH2 spectral editing showed two resolved OCH2 bands, a more intense one from O-CH2 ethers of C6 at >69 ppm and a smaller one from its esters and possibly residual CH2-OH groups, near 63 ppm. The strong intensities of resolved signals of acetyl, succinoyl, and oxypropyl substituents indicated the substitution of >85% of the OH groups in HPMCAS. The side-group concentrations in three different grades of HPMCAS were quantified.
{"title":"Corrected solid-state 13C nuclear magnetic resonance peak assignment and side-group quantification of hydroxypropyl methylcellulose acetyl succinate pharmaceutical excipients","authors":"Zhaoxi Zheng, Yongchao Su, Klaus Schmidt-Rohr","doi":"10.1002/mrc.5390","DOIUrl":"https://doi.org/10.1002/mrc.5390","url":null,"abstract":"<p>Hydroxypropyl methylcellulose acetyl succinate (HPMCAS) is widely used as a pharmaceutical excipient, making a detailed understanding of its tunable structure important for formulation design. Several recently reported peak assignments in the solid-state <sup>13</sup>C NMR spectrum of HPMCAS have been corrected here using peak integrals in quantitative spectra, spectral editing, empirical chemical-shift predictions based on solution NMR, and full spectrum simulation analogous to deconvolution. Unlike in cellulose, the strong peak at 84 ppm must be assigned to C2 and C3 methyl ethers, instead of regular C4 of cellulose. The proposed assignment of signals at <65 ppm to OCH sites, including C5 of cellulose, could not be confirmed. CH<sub>2</sub> spectral editing showed two resolved OCH<sub>2</sub> bands, a more intense one from O-CH<sub>2</sub> ethers of C6 at >69 ppm and a smaller one from its esters and possibly residual CH<sub>2</sub>-OH groups, near 63 ppm. The strong intensities of resolved signals of acetyl, succinoyl, and oxypropyl substituents indicated the substitution of >85% of the OH groups in HPMCAS. The side-group concentrations in three different grades of HPMCAS were quantified.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 11","pages":"595-605"},"PeriodicalIF":2.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50155699","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}
Sulfur-33(33S) stable-isotope labeled taurine, 2-aminoethanesulfonic acid, has been synthesized, and a series of solution and solid-state 33S nuclear magnetic resonance (NMR) experiments at 14.1 and 18.8 T, respectively, have been carried out at room temperature. The single peak of a solution 33S NMR spectrum in 0.1-mM [33S]-taurine in D2O can be observed with the signal-to-noise (S/N) ratio of 9 in 40,000 scans, which paves the way toward in vivo analysis of pharmacokinetics and metabolism of 33S-labeled taurine. Undistorted magic-angle-spinning (MAS) and static 33S NMR spectra of polycrystalline [33S]-taurine are observed with sufficient S/N ratios for analysis, and the magnitudes of 33S EFG and CS tensors can be obtained.
{"title":"Solution and solid-state 33S NMR studies of 33S-labeled taurine","authors":"Yuichi Masuda, Shinobu Ohki, Yuuki Mogami, Kenzo Deguchi, Kenjiro Hashi, Atsushi Goto, Tadashi Shimizu, Kazuhiko Yamada","doi":"10.1002/mrc.5387","DOIUrl":"https://doi.org/10.1002/mrc.5387","url":null,"abstract":"<p>Sulfur-33(<sup>33</sup>S) stable-isotope labeled taurine, 2-aminoethanesulfonic acid, has been synthesized, and a series of solution and solid-state <sup>33</sup>S nuclear magnetic resonance (NMR) experiments at 14.1 and 18.8 T, respectively, have been carried out at room temperature. The single peak of a solution <sup>33</sup>S NMR spectrum in 0.1-mM [<sup>33</sup>S]-taurine in D<sub>2</sub>O can be observed with the signal-to-noise (S/N) ratio of 9 in 40,000 scans, which paves the way toward in vivo analysis of pharmacokinetics and metabolism of <sup>33</sup>S-labeled taurine. Undistorted magic-angle-spinning (MAS) and static <sup>33</sup>S NMR spectra of polycrystalline [<sup>33</sup>S]-taurine are observed with sufficient S/N ratios for analysis, and the magnitudes of <sup>33</sup>S EFG and CS tensors can be obtained.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 11","pages":"589-594"},"PeriodicalIF":2.0,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50141621","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}