Artigos de revistas: "NMR methodology"

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CHAZIN, W. "NMR structures and methodology". Current Biology 2, n.º 9 (setembro de 1992): 510. http://dx.doi.org/10.1016/0960-9822(92)90693-5.

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Chazin, Walter J. "NMR structures and methodology". Current Opinion in Biotechnology 3, n.º 4 (agosto de 1992): 326–32. http://dx.doi.org/10.1016/0958-1669(92)90159-g.

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Bell, Nicholle G. A., Lorna Murray, Margaret C. Graham e Dušan Uhrín. "NMR methodology for complex mixture ‘separation’". Chem. Commun. 50, n.º 14 (2014): 1694–97. http://dx.doi.org/10.1039/c3cc48907h.

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McDevitt, Jayne C., Riju A. Gupta, Sydney G. Dickinson, Phillip L. Martin, Jean Rieuthavorn, Amy Freund, Marie C. Pizzorno, Elizabeth A. Capaldi e David Rovnyak. "Methodology for Single Bee and Bee Brain 1H-NMR Metabolomics". Metabolites 11, n.º 12 (13 de dezembro de 2021): 864. http://dx.doi.org/10.3390/metabo11120864.

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The feasibility of metabolomic 1H NMR spectroscopy is demonstrated for its potential to help unravel the complex factors that are impacting honeybee health and behavior. Targeted and non-targeted 1H NMR metabolic profiles of liquid and tissue samples of organisms could provide information on the pathology of infections and on environmentally induced stresses. This work reports on establishing extraction methods for NMR metabolic characterization of Apis mellifera, the European honeybee, describes the currently assignable aqueous metabolome, and gives examples of diverse samples (brain, head, body, whole bee) and biologically meaningful metabolic variation (drone, forager, day old, deformed wing virus). Both high-field (600 MHz) and low-field (80 MHz) methods are applicable, and 1H NMR can observe a useful subset of the metabolome of single bees using accessible NMR instrumentation (600 MHz, inverse room temperature probe) in order to avoid pooling several bees. Metabolite levels and changes can be measured by NMR in the bee brain, where dysregulation of metabolic processes has been implicated in colony collapse. For a targeted study, the ability to recover 10-hydroxy-2-decenoic acid in mandibular glands is shown, as well as markers of interest in the bee brain such as GABA (4-aminobutyrate), proline, and arginine. The findings here support the growing use of 1H NMR more broadly in bees, native pollinators, and insects.

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Zı́dek, Lukáš, Richard Štefl e Vladimı́ř Sklenář. "NMR methodology for the study of nucleic acids". Current Opinion in Structural Biology 11, n.º 3 (junho de 2001): 275–81. http://dx.doi.org/10.1016/s0959-440x(00)00218-9.

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Sobolev, Anatoly, Donatella Capitani, Donato Giannino, Chiara Nicolodi, Giulio Testone, Flavio Santoro, Giovanna Frugis et al. "NMR-Metabolic Methodology in the Study of GM Foods". Nutrients 2, n.º 1 (13 de janeiro de 2010): 1–15. http://dx.doi.org/10.3390/nu2010001.

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Foston, Marcus B., Chistopher A. Hubbell e Art J. Ragauskas. "Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure". Materials 4, n.º 11 (7 de novembro de 2011): 1985–2002. http://dx.doi.org/10.3390/ma4111985.

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Sauers, Ronald R. "Cyclopropanes: Calculation of NMR spectra by ab initio methodology". Tetrahedron 54, n.º 3-4 (janeiro de 1998): 337–48. http://dx.doi.org/10.1016/s0040-4020(97)10276-9.

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Pileio, Giuseppe. "Singlet NMR methodology in two-spin-1/2 systems". Progress in Nuclear Magnetic Resonance Spectroscopy 98-99 (fevereiro de 2017): 1–19. http://dx.doi.org/10.1016/j.pnmrs.2016.11.002.

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Chalmers, Gordon R., Alexander Eletsky, Laura C. Morris, Jeong-Yeh Yang, Fang Tian, Robert J. Woods, Kelley W. Moremen e James H. Prestegard. "NMR Resonance Assignment Methodology: Characterizing Large Sparsely Labeled Glycoproteins". Journal of Molecular Biology 431, n.º 12 (maio de 2019): 2369–82. http://dx.doi.org/10.1016/j.jmb.2019.04.029.

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Saidian, Milad, Torben Rasmussen, Mosab Nasser, Andres Mantilla e Rick Tobin. "Qualitative and quantitative reservoir bitumen characterization: A core to log correlation methodology". Interpretation 3, n.º 1 (1 de fevereiro de 2015): SA143—SA158. http://dx.doi.org/10.1190/int-2014-0052.1.

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Reservoir bitumen is a highly viscous, asphaltene-rich hydrocarbon that can have important effects on reservoir performance. Discriminating between producible oil and reservoir bitumen is critical for recoverable hydrocarbon volume calculations and production planning, yet the lack of resistivity contrast between the two makes it difficult, if not impossible, to make such differentiation using conventional logs. However, the nuclear magnetic resonance (NMR) response in bitumen-rich zones is dominated by short transverse relaxation times ([Formula: see text]) and a low apparent fluid hydrogen index ([Formula: see text]), providing an opportunity to identify the presence of reservoir bitumen. Therefore, NMR logging technology becomes crucial in the characterization of reservoirs in which the presence of bitumen may be of concern. We used NMR and other log data to identify and quantify the occurrence of reservoir bitumen in a carbonate reservoir. A thorough petrophysical evaluation was performed using a full suite of logs, formation pressure measurements, and laboratory core analysis data. We discuss several quick methods to identify intervals with a higher chance of reservoir bitumen presence. The short transverse relaxation times ([Formula: see text]) and consequently lower [Formula: see text] logarithmic mean time values are characteristics of bitumen-rich zones. Another characteristic is low [Formula: see text] in these zones and consequently lower NMR porosity estimates when compared to porosity estimates from the density and neutron tools. We analyzed 2D longitudinal-transverse relaxation time ([Formula: see text]) maps for core samples at different depths to confirm the presence of reservoir bitumen in some wells using laboratory low-field NMR data. We observed a high [Formula: see text] ratio at various depths, which is an indication of high-molecular-weight hydrocarbons. The presence of bitumen at the same depths was confirmed by thin section analysis, and it is the likely cause for failed formation pressure testing attempts at those depth intervals. Partial cleaning of reservoir bitumen-rich core plugs results in helium-injection porosity estimates that are too low, and they are closer to the NMR porosity than to density porosity, the latter being more consistent with actual values. In addition, the grain density (GD) calculated by He injection is significantly lower than the GD estimated from elemental capture spectroscopy and X-ray diffraction techniques. Disregarding these effects complicates the core to log correlation, which is common practice for porosity calculations using the density log. A volumetric rock model was used to reconcile core and log data as well as to calculate the saturation of reservoir bitumen. The methodologies for reservoir bitumen characterization introduced here can be applied successfully in different reservoirs for more reliable and precise reservoir evaluation and production planning.

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Sobolev, Anatoly P., Cinzia Ingallina, Mattia Spano, Giacomo Di Matteo e Luisa Mannina. "NMR-Based Approaches in the Study of Foods". Molecules 27, n.º 22 (15 de novembro de 2022): 7906. http://dx.doi.org/10.3390/molecules27227906.

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In this review, the three different NMR-based approaches usually used to study foodstuffs are described, reporting specific examples. The first approach starts with the food of interest that can be investigated using different complementary NMR methodologies to obtain a comprehensive picture of food composition and structure; another approach starts with the specific problem related to a given food (frauds, safety, traceability, geographical and botanical origin, farming methods, food processing, maturation and ageing, etc.) that can be addressed by choosing the most suitable NMR methodology; finally, it is possible to start from a single NMR methodology, developing a broad range of applications to tackle common food-related challenges and different aspects related to foods.

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Jurkiewicz, Antoni, e Gary E. Maciel. "13C NMR Spin-Lattice Relaxation Properties and Quantitative Analytical Methodology of 13C NMR Spectroscopy for Coals". Analytical Chemistry 67, n.º 13 (julho de 1995): 2188–94. http://dx.doi.org/10.1021/ac00109a043.

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Sobolev, Anatoly, Luisa Mannina, Noemi Proietti, Simone Carradori, Maria Daglia, Anna Giusti, Riccarda Antiochia e Donatella Capitani. "Untargeted NMR-Based Methodology in the Study of Fruit Metabolites". Molecules 20, n.º 3 (4 de março de 2015): 4088–108. http://dx.doi.org/10.3390/molecules20034088.

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McLeod, Marc Avery, Mukundan Ravagan, Daniel Downes e Matthew E. Merritt. "Characterization Of Liver Metabolism By NMR‐Guided GC‐MS Methodology". FASEB Journal 34, S1 (abril de 2020): 1. http://dx.doi.org/10.1096/fasebj.2020.34.s1.09759.

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Bezençon, Jacqueline, Matthias B. Wittwer, Brian Cutting, Martin Smieško, Bjoern Wagner, Manfred Kansy e Beat Ernst. "pKa determination by 1H NMR spectroscopy – An old methodology revisited". Journal of Pharmaceutical and Biomedical Analysis 93 (maio de 2014): 147–55. http://dx.doi.org/10.1016/j.jpba.2013.12.014.

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Marble, Andrew E., Igor V. Mastikhin, Bruce G. Colpitts e Bruce J. Balcom. "An analytical methodology for magnetic field control in unilateral NMR". Journal of Magnetic Resonance 174, n.º 1 (maio de 2005): 78–87. http://dx.doi.org/10.1016/j.jmr.2005.01.009.

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García-Martínez, Fernando, Miguel Quiroga, Pedro Rodríguez-Dafonte, Mercedes Parajó e Luis Garcia-Rio. "Displacement assay methodology for pseudorotaxane formation in the millisecond time-scale". Pure and Applied Chemistry 89, n.º 6 (27 de junho de 2017): 821–27. http://dx.doi.org/10.1515/pac-2016-1101.

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AbstractRotaxanes, formed by an axis through the cavity of a macrocycle, are promising systems for the construction of molecular machines. A very limited number of experimental techniques are available for mechanistic studies since only mechanical bonds are formed, being NMR one of the most widely used. The major inconvenience derived from NMR use is the time-scale for threading/dethreading processes lasting a few minutes in the case of faster processes. In the present manuscript, we report the application of a new kinetic methodology based on a displacement assay for cyclodextrin-based pseudorotaxane formation. By coupling a very fast (microseconds time-scale) binding/dissociation of nitrophenol to α-CD with a dicationic axle threading/dethreading process, we have been able to study kinetic processes taking place in the millisecond time-scale.

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Zhang, Yu, Jianxiang Zhao, Ying Gu, Yu Zhang, Yi Chen, Ping Song e Tao Yang. "A Methodology Study on the Optimal Detection of Oil and Moisture Content in Soybeans Using LF-NMR and Its 2D T1-T2 Nuclear Magnetic Technology". Agronomy 13, n.º 4 (12 de abril de 2023): 1102. http://dx.doi.org/10.3390/agronomy13041102.

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In this study, we aimed to provide an accurate method for the detection of oil and moisture content in soybeans. Introducing two-dimensional low-field nuclear magnetic resonance (LF-2D-NMR) qualitatively solved the problem of overlapping component signals that one-dimensional (1D) LF-NMR techniques cannot distinguish in soybean detection research. Soxhlet extraction, oven drying, LF-NMR spectrum, and LF-NMR oil and moisture content software were used to detect soybean oil and moisture content. The comparison showed that the LF-NMR oil and moisture content software was faster and more accurate than the other methods. The specific identification of the oil and moisture signals of soybean seeds using longitudinal relaxation time (T1) and transverse relaxation time (T2) successfully solved the problems of less mobile water, overlapping free water, and oil signals. Therefore, LF-2D-NMR can complement conventional LF-NMR assays, and this study provides a new method for the analysis and detection of moisture and oil in soybeans.

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Vaara, Juha. "Quantum-Chemical Approach to Nuclear Magnetic Resonance of Paramagnetic Systems". Annales Academiae Scientiarum Fennicae, n.º 1 (30 de maio de 2023): 96–115. http://dx.doi.org/10.57048/aasf.130117.

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Nuclear magnetic resonance (NMR) is a central method for investigating the microscopic structure and dynamics of molecules and materials, with numerous applications in science, technology, and medicine. Computational modelling is indispensable in NMR research due to the indirect nature of NMR information and the rich physical phenomenology behind its observables. While NMR is conventionally used to study diamagnetic systems, paramagnetic NMR (pNMR) of electronically open-shell systems is rapidly gaining importance. This inaugural article concerns the methodology and application of computational molecular science to the observables pNMR, including current challenges and outlook for the future.

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Indra, Beni, Nur Indrawaty Lipoeto, Hardisman Hardisman, Andani Eka Putra, Djong Hon Tjong, Sukri Rahman, Elfira Yusri, Muhammad Ridho Bilhaq, Yusan Pratama e Yudha Risman. "The Severity of COVID-19 and its Correlation with Inflammation Biomarkers". Open Access Macedonian Journal of Medical Sciences 10, A (27 de maio de 2022): 911–15. http://dx.doi.org/10.3889/oamjms.2022.9639.

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Introduction: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov2) or Covid-19 has been spread quickly and caused 5 million deaths until February 2022. Severe symptoms of the infection may lead to death that prompt appropriate clinical diagnosis and adequate treatment going to be necessary. Covid-19 shows a severe inflammatory response which causes an imbalance in the immune response. Therefore, circulating biomarkers that can represent inflammation and immune status are potential predictors for the prognosis of COVID-19 patients. This study aims to know the role of Neutrophil-Lymphocyte Ratio (NLR), Neutrophil Monocyte Ratio (NMR), and Lymphocyte-monocyte Ratio (LMR) as inflammatory biomarkers for the severity of Covid-19. Methodology: This study is a single-center retrospective cohort study. The sample of this study was taken by consecutive sampling with complete clinical data from 893 Covid-19 patients from Andalas University Teaching Hospital from April 2020 to September 2021. This study uses SPSS Version 25.0 for data management and analysis. Result: Most of the degrees of Covid-19 infection were mild degrees as many as 597 people with an NLR average value of 2.07 (0.27-34.50), and NMR average value of 7.86 (3-46), an LMR average value of 3.67 (0.25-25), an ANC value of 3.990 (945-45). 14,608). Most of the degrees of infection in patients with negative PCR results were moderate degrees as many as 70 people with a mean NLR value of 9.0694 (0.51-47.50), a mean NMR value of 18.6199 (1.15-47.50), and a mean LMR was 3.0324 (0.29-19.50), the ANC value was 9769.73 (1.088-37,219). There was a relationship between the degree of Covid-19 infection and the NLR value (p=0.144), as well as the LMR (p=0.000), NMR(p=0.000), and ANC (p=0.000). There was no relationship between the degree of infection in the negative PCR patient group and the NLR value (p=0.000), as well as the LMR (p=0.700), NMR(p=0.120), and ANC (p=0.90). Conclusion: The severity of Covid-19 symptoms could be predicted through inflammatory biomarkers such as NLR, LMR, and NMR.

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Wu, Gang. "Recent developments in solid-state nuclear magnetic resonance of quadrupolar nuclei and applications to biological systems". Biochemistry and Cell Biology 76, n.º 2-3 (1 de maio de 1998): 429–42. http://dx.doi.org/10.1139/o98-045.

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Recent advances in nuclear magnetic resonance (NMR) methodology and improvements in high-field NMR instrumentation have generated a new wave of research interests in the application of solid-state NMR to the study of quadrupolar nuclei. These developments now permit increasingly complex biological systems to be probed by quadrupolar NMR. In this review I describe a few recent developments in NMR studies of quadrupolar nuclei and demonstrate the potential of solid-state quadrupolar NMR in the study of biological systems. In particular, I discuss the application of solid-state NMR of 17O, 67Zn, 59Co, 23Na, and 39K nuclei with a prognosis for future work.Key words: nuclear magnetic resonance, quadrupole, solid state, biological system.

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Monaco, Serena, Jonathan Ramírez-Cárdenas, Ana Teresa Carmona, Inmaculada Robina e Jesus Angulo. "Inter-Ligand STD NMR: An Efficient 1D NMR Approach to Probe Relative Orientation of Ligands in a Multi-Subsite Protein Binding Pocket". Pharmaceuticals 15, n.º 8 (21 de agosto de 2022): 1030. http://dx.doi.org/10.3390/ph15081030.

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In recent years, Saturation Transfer Difference NMR (STD NMR) has been proven to be a powerful and versatile ligand-based NMR technique to elucidate crucial aspects in the investigation of protein-ligand complexes. Novel STD NMR approaches relying on “multi-frequency” irradiation have enabled us to even elucidate specific ligand-amino acid interactions and explore the binding of fragments in previously unknown binding subsites. Exploring multi-subsite protein binding pockets is especially important in Fragment Based Drug Discovery (FBDD) to design leads of increased specificity and efficacy. We hereby propose a novel multi-frequency STD NMR approach based on direct irradiation of one of the ligands in a multi-ligand binding process, to probe the vicinity and explore the relative orientation of fragments in adjacent binding sub-sites, which we called Inter-Ligand STD NMR (IL-STD NMR). We proved its applicability on (i) a standard protein-ligand system commonly used for ligand-observed NMR benchmarking: Naproxen as bound to Bovine Serum Albumin, and (ii) the biologically relevant system of Cholera Toxin Subunit B and two inhibitors adjacently bound within the GM1 binding site. Relative to Inter-Ligand NOE (ILOE), the current state-of-the-art methodology to probe relative orientations of adjacent ligands, IL-STD NMR requires about one tenth of the experimental time and protein consumption, making it a competitive methodology with the potential to be applied in the pharmaceutical industries.

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Barrulas, Raquel V., Tiago G. Paiva e Marta C. Corvo. "NMR methodology for a rational selection of ionic liquids: extracting polyphenols". Separation and Purification Technology 221 (agosto de 2019): 29–37. http://dx.doi.org/10.1016/j.seppur.2019.03.077.

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Landucci, Lawrence L. "Quantitative13C NMR Characterization of Lignin 1. A Methodology for High Precision". Holzforschung 39, n.º 6 (janeiro de 1985): 355–60. http://dx.doi.org/10.1515/hfsg.1985.39.6.355.

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Pastor, Aurelia, e Eloísa Martínez-Viviente. "NMR spectroscopy in coordination supramolecular chemistry: A unique and powerful methodology". Coordination Chemistry Reviews 252, n.º 21-22 (novembro de 2008): 2314–45. http://dx.doi.org/10.1016/j.ccr.2008.01.025.

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SAUERS, R. R. "ChemInform Abstract: Cyclopropanes: Calculation of NMR Spectra by ab initio Methodology." ChemInform 29, n.º 20 (22 de junho de 2010): no. http://dx.doi.org/10.1002/chin.199820270.

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RAMALHO, TEODORICO C., ELAINE F. F. DA CUNHA, FERNANDO C. PEIXOTO e JOSÉ DANIEL FIGUEROA-VILLAR. "COMPUTATIONAL NMR INVESTIGATION OF RADIOSENSITIZER IN SOLUTION". Journal of Theoretical and Computational Chemistry 07, n.º 01 (fevereiro de 2008): 37–52. http://dx.doi.org/10.1142/s0219633608003575.

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15 N and 13 C NMR chemical shifts for four radiosensitizers have been calculated and compared with experimental data. The thermal and solvent effects on NMR spectra were simulated with the polarizable continuum model and an alternative molecular dynamics/quantum mechanics methodology. Magnetic shielding tensors were evaluated at the GIAO-B3LYP and GIAO-OPBE level using II' and 6-311+(2D,P) basis sets, showing that it is essential to incorporate the dynamics and solvent effects on NMR calculations in condensed phases.

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Li, Xiang, Huaili Zheng, Baoyu Gao, Yongjun Sun, Xiaomin Tang e Bincheng Xu. "Optimized preparation of micro-block CPAM by response surface methodology and evaluation of dewatering performance". RSC Advances 7, n.º 1 (2017): 208–17. http://dx.doi.org/10.1039/c6ra25245a.

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Kim, Jongphil, Hin Kyeol Woo, Dixon Vimalajeewa e Brani Vidakovic. "Analysis and classification of 1H-NMR spectra by multifractal analysis". PLOS ONE 18, n.º 6 (8 de junho de 2023): e0286205. http://dx.doi.org/10.1371/journal.pone.0286205.

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The objective of this research focuses on the development of a statistical methodology able to answer the question of whether variation in the intake of sulfur amino acids (SAA) affects the metabolic process. Traditional approaches, which evaluate specific biomarkers after a series of preprocessing procedures, have been criticized as not being fully informative, as well as inappropriate for translation of methodology. Rather than focusing on particular biomarkers, our proposed methodology involves the multifractal analysis that measures the inhomogeneity of regularity of the proton nuclear magnetic resonance (1H-NMR) spectrum by wavelet-based multifractal spectrum. With two different statistical models (Model-I and Model-II), three different geometric features of the multifractal spectrum of each 1H-NMR spectrum (spectral mode, left slope, and broadness) are employed to evaluate the effect of SAA and discriminate 1H-NMR spectra associated with different treatments. The investigated effects of SAA include group effect (high and low doses of SAA), depletion/repletion effect, and time over data effect. The 1H-NMR spectra analysis outcomes show that group effect is significant for both models. The hourly variation in time and depletion/repletion effects does not show noticeable differences for the three features in Model-I. However, these two effects are significant for the spectral mode feature in Model-II. The 1H-NMR spectra of the SAA low groups exhibit highly regular patterns with more variability than that of the SAA high groups for both models. Moreover, the discriminatory analysis conducted using the support vector machine and the principal components analysis shows that the 1H-NMR spectra of SAA high and low groups can be easily discriminatory for both models, while the spectra of depletion and repletion within these groups are discriminatory for Model-I and Model-II. Therefore, the study outcomes imply that the amount of SAA is important and that SAA intake affects mostly the hourly variation of the metabolic process and the difference between depletion and repletion each day. In conclusion, the proposed multifractal analysis of 1H-NMR spectra provides a novel tool to investigate metabolic processes.

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Monakhova, Yulia B., Gabriele Randel e Bernd W. K. Diehl. "Automated Control of the Organic and Inorganic Composition of Aloe vera Extracts Using 1H NMR Spectroscopy". Journal of AOAC INTERNATIONAL 99, n.º 5 (1 de setembro de 2016): 1213–18. http://dx.doi.org/10.5740/jaoacint.16-0020.

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Abstract Recent classification of Aloe vera whole-leaf extract by the International Agency for Research and Cancer as a possible carcinogen to humans as well as the continuous adulteration of A. vera's authentic material have generated renewed interest in controlling A. vera. The existing NMR spectroscopic method for the analysis of A. vera, which is based on a routine developed at Spectral Service, was extended. Apart from aloverose, glucose, malic acid, lactic acid, citric acid, whole-leaf material (WLM), acetic acid, fumaric acid, sodium benzoate, and potassium sorbate, the quantification of Mg2+, Ca2+, and fructose is possible with the addition of a Cs-EDTA solution to sample. The proposed methodology was automated, which includes phasing, baseline-correction, deconvolution (based on the Lorentzian function), integration, quantification, and reporting. The NMR method was applied to 41 A. vera preparations in the form of liquid A. vera juice and solid A. vera powder. The advantages of the new NMR methodology over the previous method were discussed. Correlation between the new and standard NMR methodologies was significant for aloverose, glucose, malic acid, lactic acid, citric acid, and WLM (P < 0.0001, R2 = 0.99). NMR was found to be suitable for the automated simultaneous quantitative determination of 13 parameters in A. vera.

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Besse, Pascale, Bruno Combourieu, Gaëlle Boyse, Martine Sancelme, Heleen De Wever e Anne-Marie Delort. "Long-Range 1H-15N Heteronuclear Shift Correlation at Natural Abundance: a Tool To Study Benzothiazole Biodegradation by Two RhodococcusStrains". Applied and Environmental Microbiology 67, n.º 4 (1 de abril de 2001): 1412–17. http://dx.doi.org/10.1128/aem.67.4.1412-1417.2001.

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ABSTRACT The biodegradation of benzothiazole and 2-hydroxybenzothiazole by two strains of Rhodococcus was monitored by reversed phase high-pressure liquid chromatography and by 1H nuclear magnetic resonance (NMR). Both xenobiotics were biotransformed into a hydroxylated derivative of 2-hydroxybenzothiazole by these two strains. The chemical structure of this metabolite was determined by a new NMR methodology: long-range 1H-15N heteronuclear shift correlation without any previous 15N enrichment of the compound. This powerful NMR tool allowed us to assign the metabolite structure to 2,6-dihydroxybenzothiazole.

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Crozier, Stuart, Stephen Dodd e David M. Doddrell. "A novel design methodology for Nth order, shielded longitudinal coils for NMR". Measurement Science and Technology 7, n.º 1 (1 de janeiro de 1996): 36–41. http://dx.doi.org/10.1088/0957-0233/7/1/005.

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Martin, Rachel W., John E. Kelly e Jessica I. Kelz. "Advances in instrumentation and methodology for solid-state NMR of biological assemblies". Journal of Structural Biology 206, n.º 1 (abril de 2019): 73–89. http://dx.doi.org/10.1016/j.jsb.2018.09.003.

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Sarotti, Ariel M., e Silvina C. Pellegrinet. "Application of the Multi-standard Methodology for Calculating 1H NMR Chemical Shifts". Journal of Organic Chemistry 77, n.º 14 (3 de julho de 2012): 6059–65. http://dx.doi.org/10.1021/jo3008447.

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Lee, Garry S. H., Kari M. Brinch, Kamali Kannangara, Michael Dawson e Michael A. Wilson. "A Methodology Based on NMR Spectroscopy for the Forensic Analysis of Condoms". Journal of Forensic Sciences 46, n.º 4 (1 de julho de 2001): 15052J. http://dx.doi.org/10.1520/jfs15052j.

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Basil Hans, V. "Role and Responsibilities of Managerial Economists: Empowering Business through Methodology and Strategy". Nitte Management Review 10, n.º 2 (21 de dezembro de 2016): 27. http://dx.doi.org/10.17493/nmr/2016/118221.

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Khaskel, Anamika, Pranjit Barman, Subir Kumar Maiti e Utpal Jana. "Nebivolol nanoparticles: a first catalytic use in Biginelli and Biginelli-like reactions". Canadian Journal of Chemistry 96, n.º 12 (dezembro de 2018): 1021–25. http://dx.doi.org/10.1139/cjc-2017-0621.

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Herein, we report the catalytic activity of nebivolol nanoparticles a novel organocatalyst for the synthesis of DHPMs and DHPM-5-carboxamides. The nanoparticles are confirmed by DSC, TEM, AFM, and IR spectroscopy. The catalyst can be readily recovered and reused for the next four runs without any significant impact on the yields of the products. The products are fully characterized by FTIR, 1H NMR, 13C NMR, and distortionless enhanced polarization transfer (DEPT) NMR. The methodology adopted here offers several advantages such as solvent-free reaction, low loading of catalyst, short reaction times, and quantifiable yields.

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Muniyappan, Srinivasan, Yuxi Lin, Young-Ho Lee e Jin Hae Kim. "17O NMR Spectroscopy: A Novel Probe for Characterizing Protein Structure and Folding". Biology 10, n.º 6 (21 de maio de 2021): 453. http://dx.doi.org/10.3390/biology10060453.

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Oxygen is a key atom that maintains biomolecular structures, regulates various physiological processes, and mediates various biomolecular interactions. Oxygen-17 (17O), therefore, has been proposed as a useful probe that can provide detailed information about various physicochemical features of proteins. This is attributed to the facts that (1) 17O is an active isotope for nuclear magnetic resonance (NMR) spectroscopic approaches; (2) NMR spectroscopy is one of the most suitable tools for characterizing the structural and dynamical features of biomolecules under native-like conditions; and (3) oxygen atoms are frequently involved in essential hydrogen bonds for the structural and functional integrity of proteins or related biomolecules. Although 17O NMR spectroscopic investigations of biomolecules have been considerably hampered due to low natural abundance and the quadruple characteristics of the 17O nucleus, recent theoretical and technical developments have revolutionized this methodology to be optimally poised as a unique and widely applicable tool for determining protein structure and dynamics. In this review, we recapitulate recent developments in 17O NMR spectroscopy to characterize protein structure and folding. In addition, we discuss the highly promising advantages of this methodology over other techniques and explain why further technical and experimental advancements are highly desired.

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Avram, Liat, Mark A. Iron e Amnon Bar-Shir. "Amplifying undetectable NMR signals to study host–guest interactions and exchange". Chemical Science 7, n.º 12 (2016): 6905–9. http://dx.doi.org/10.1039/c6sc04083g.

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Wu, Di, Yuanming Zhai, Jin Yan, Kailin Xu, Qing Wang, Yuanzhi Li e Hui Li. "Binding mechanism of tauroursodeoxycholic acid to human serum albumin: insights from NMR relaxation and docking simulations". RSC Advances 5, n.º 15 (2015): 11036–42. http://dx.doi.org/10.1039/c4ra11422a.

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Smith, Alan J. R., Richard York, Dušan Uhrín e Nicholle G. A. Bell. "New ¹⁹F NMR methodology reveals structures of molecules in complex mixtures of fluorinated compounds". Chemical Science 13, n.º 13 (2022): 3766–74. http://dx.doi.org/10.1039/d1sc06057k.

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19F-centred NMR structure determination protocol alleviates the need for compound separation. Disinfection byproducts of chloramination were unraveled by analyzing the reaction pathways of a single fluorinated molecule.

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Wüthrich, Kurt. "Nuclear magnetic resonance – from molecules to man". Quarterly Reviews of Biophysics 19, n.º 1-2 (fevereiro de 1987): 3–5. http://dx.doi.org/10.1017/s0033583500004005.

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Initial observations of the physical phenomenon of nuclear magnetic resonance (NMR) date back to the late 1940s. In the following two decades high-resolution NMR in solution became an indispensible analytical tool in chemistry, and solid state NMR had an increasingly important role in physics. Some of the potentialities of the method for investigations of complex biological systems had also long been anticipated, and initial experiments with biological specimens were described already 30 years ago. In practice, however, biological applications of NMR have become really attractive only during the last decade, following revolutionary advances in NMR instrumentation and the methodology for their use. NMR projects in biology and medicine now include studies of biomacromolecular structure and function, work on biological membranes, in vivo studies of biochemical processes, and imaging of macroscopic objects. Because of imminent practical applications in medical diagnosis and thanks to extensive coverage by the popular news media, interest in some of the recent developments spreads far beyond the scientific community, making NMR a widely popular field.

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Iglesias, Dacio Adhemar, Danila Luján Ruiz e Patricia Ercilia Allegretti. "2-Cyanobenzoic Acids: Tautomeric Equilibria Study". Australian Journal of Chemistry 68, n.º 3 (2015): 461. http://dx.doi.org/10.1071/ch14273.

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Evidence of ring–chain tautomerism in the gas phase from mass spectrometry and in solution determined by means of 1H NMR and 13C NMR is reported for 2-cyanobenzoic acids. The analysis of the corresponding spectra has allowed specific assignment of fragment ions to tautomers. The predictive value of this methodology is supported by the influence of the substitution pattern of these compounds on this equilibrium.

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Monakhova, Yulia B., Martina Betzgen e Bernd W. K. Diehl. "1H NMR as a release methodology for the analysis of phospholipids and other constituents in infant nutrition". Analytical Methods 8, n.º 41 (2016): 7493–99. http://dx.doi.org/10.1039/c6ay02063a.

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An ¹H NMR method was developed to control five phospholipid (PL) species, namely, phosphatidylcholine (PC), sphingomyelin (SPH), phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI) in infant nutrition.

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Borges, Ricardo Batista, Antonio Laverde Jr., André Luiz Meleiro Porto e Anita Jocelyne Marsaioli. "HR-DOSY and sulfoxide enantiomeric discrimination by cyclodextrin". Spectroscopy 14, n.º 4 (2000): 203–13. http://dx.doi.org/10.1155/2000/454903.

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Racemic and chiral ethyl-phenylsulfoxide (solute) andβ-cyclodextrin (chiral selector) were used to compare two NMR methodologies to predict RP-HPLC enantiomeric resolution efficiency. One of them based on the classical approach involving apparent binding constants and complexation‒induced chemical shifts at saturation and the other based on13C NMR signal splittings (solute and chiral selector in stoichiometric ratio) and HR-DOSY of the same solution. We have concluded that the latter methodology is rather efficient and though more elaborate from the NMR point of view, the results are promising and constitute an alternative method to investigate chiral recognition and other supramolecular phenomena.

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Paluch, Piotr, Tomasz Pawlak, Agata Jeziorna, Julien Trébosc, Guangjin Hou, Alexander J. Vega, Jean-Paul Amoureux, Martin Dracinsky, Tatyana Polenova e Marek J. Potrzebowski. "Analysis of local molecular motions of aromatic sidechains in proteins by 2D and 3D fast MAS NMR spectroscopy and quantum mechanical calculations". Physical Chemistry Chemical Physics 17, n.º 43 (2015): 28789–801. http://dx.doi.org/10.1039/c5cp04475h.

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Lachenmeier, Dirk W., Jan Teipel, Andreas Scharinger, Thomas Kuballa, Stephan G. Walch, Franziska Grosch, Mirko Bunzel, Alex O. Okaru e Steffen Schwarz. "Fully Automated Identification of Coffee Species and Simultaneous Quantification of Furfuryl Alcohol Using NMR Spectroscopy". Journal of AOAC INTERNATIONAL 103, n.º 2 (março de 2020): 306–14. http://dx.doi.org/10.1093/jaocint/qsz020.

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Abstract Background Coffee is a popular beverage with two species, Coffea canephora and C. arabica, being commercially exploited. The quality and commercial value of coffee is dependent on species and processing. C. arabica typically obtains a higher price on the market compared to C. canephora. Coffee beans undergo roasting during processing, resulting in the formation of flavor compounds including furfuryl alcohol which has been classified by the International Agency for Research on Cancer as possibly carcinogenic to humans (Group 2B). Objective The aim of this study was to identify coffee species and other properties using nuclear magnetic resonance (NMR) spectroscopy, specifically to conduct quantification of the roasting process contaminant furfuryl alcohol. Method The quantification of furfuryl alcohol was performed from the NMR spectra using the pulse length-based concentration (PULCON) methodology. Prior to NMR analysis, samples were extracted using deuterated chloroform. Results Roasting experiments identified the maximum roasting temperature to be the most significant factor in the formation of furfuryl alcohol. Among the coffee species, C. canephora was found to contain a relatively lower amount of furfuryl alcohol compared to C. arabica. The roasting of wet processed coffee resulted in higher contents of furfuryl alcohol. Geographical origin and variety within species had no influence on the furfuryl alcohol content. Conclusion Validation results show that NMR spectroscopy is fit-for-purpose to obtain targeted information of coffee samples. Highlights The PULCON NMR methodology allows a simple, rapid and accurate determination of constituents of coffee.

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Lencina, María M. Soledad, Franco L. Redondo, Camila Müller, Vivina Hanazumi, Cristian Vitale, Mario D. Ninago, Daniel A. Vega, Marcelo A. Villar e Andrés E. Ciolino. "A Straightforward Methodology for the Synthesis of α,ω-Telechelic Poly(dimethylsiloxane)s". Australian Journal of Chemistry 71, n.º 3 (2018): 160. http://dx.doi.org/10.1071/ch17508.

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In this work we report the synthesis of α,ω-telechelic poly(dimethylsiloxane)s (α,ω-PDMS) by employing a novel bifunctional initiator obtained from a commercially available siloxane precursor, diglycidylether-terminated poly(dimethylsiloxane) (PDMS-DGE). The synthetic strategy was easily followed by different colour changes, and involved the high-vacuum reaction of sec-Bu−Li+ with 1,1′-diphenylethylene (DPE) to afford the addition adduct (bright red) that was subsequently reacted with PDMS-DGE, promoting the nuclephilic ring-opening from epoxide-end chains. The resulting bifunctional initiator (light green) was then employed to polymerize hexamethyl(cyclotrisiloxane) monomer (D3) by using conventional anionic polymerization (from light green to pale yellow). From suitable terminating agents, silane (–SiH), vinyl (–CH=CH2), hydroxy (–OH), and even methacryloyl α,ω-PDMS were obtained. 1H NMR and FT-IR analyses confirmed the presence of the targeted functional groups in the resulting polymers. However, a careful siliconization procedure should be performed over glass surfaces during the fractionation of chlorosilane ampoules in order to avoid the presence of silanol moieties that decrease end-capping efficiency. This fact was observed not only from NMR but also from size exclusion chromatography (SEC) analyses, since narrow molar masses distributions (1.15 ≤ Mw/Mn ≤ 1.3) and a good control over the resulting molar masses were observed.

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Wu, Dazhi, Junyi Wang, Tong Miao, Keyu Chen e Zilong Zhang. "Performance Optimization of FA-GGBS Geopolymer Based on Response Surface Methodology". Polymers 15, n.º 8 (14 de abril de 2023): 1881. http://dx.doi.org/10.3390/polym15081881.

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Many scholars have focused on the workability and mechanical properties of fly ash (FA)- ground granulated blast furnace slag (GGBS) geopolymer. To enhance the compressive strength of geopolymer, zeolite powder was added in the present study. A series of experiments were carried out to investigate the effect of using zeolite powder as an external admixture on the per-formance of FA-GGBS geopolymer, 17 sets of experiments were designed and tested to deter-mine the unconfined compressive strength based on the response surface methodology, and then, the optimal parameters were obtained via modeling of 3 factors (zeolite powder dosage, alkali exciter dosage, and alkali exciter modulus) and 2 levels of compressive strength (3 d and 28 d). The experimental results showed that the strength of the geopolymer was the highest when the three factors were 13.3%, 40.3%, and 1.2. Finally, a combination of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and 29Si nuclear magnetic resonance (NMR) analysis was used to conduct micromechanical analysis and explain the reaction mechanism from a microscopic perspective. The SEM and XRD analysis revealed that the microstructure of the geopolymer was the densest when the zeolite powder was doped at 13.3%, and the strength increased accordingly. The NMR and Fourier transform infrared spectroscopy analyses revealed that the absorption peak wave number band shifted toward the lower wave number band under the optimal ratio, and the silica–oxygen bond was replaced by an aluminum–oxygen bond, which generated more aluminosilicate structures.

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