2,512 results match your criteria Magnetic Resonance in Chemistry [Journal]


EPR spectroscopy of multi-component, multi-spin molecular system obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon.

Magn Reson Chem 2019 Apr 17. Epub 2019 Apr 17.

Lehrstuhl für Organische Chemie II, Ruhr-Universität, D-44780, Bochum, Germany.

Complex multi-component, multi-spin molecular system, consisting of a septet trinitrene, two quintet dinitrenes and three triplet mononitrenes, was obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon. To identify these paramagnetic products, EPR spectroscopy in combination with line-shape spectral simulations and density functional theory calculations was used. The products of the photolysis was found to be triplet 2,4-diazido-3-cyano-5-fluoropyridyl-6-nitrene (D = 1. Read More

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http://dx.doi.org/10.1002/mrc.4877DOI Listing

Prenylflavanones and lignans from the twigs of Artocarpus pithecogallus.

Magn Reson Chem 2019 Apr 17. Epub 2019 Apr 17.

School of Pharmacy, Nanchang University, Nanchang, 330006, China.

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http://dx.doi.org/10.1002/mrc.4875DOI Listing

Improvement of Bioactive Metabolite Production in Microbial Cultures - A systems approach by OSMAC and deconvolution-based HNMR quantification.

Magn Reson Chem 2019 Apr 16. Epub 2019 Apr 16.

Nucleus of Bioassays, Biosynthesis and Ecophysiology of natural products (NuBBE), Organic Chemistry Depart., Institute of Chemistry, São Paulo State University (UNESP), St. Prof. Francisco Degni, 55, Quitandinha, 14800-060, Araraquara, SP, Brazil.

Traditionally, the screening of metabolites in microbial matrices is performed by monocultures. Nonetheless, the absence of biotic and abiotic interactions generally observed in nature still limit the chemical diversity and leads to "poorer" chemical profiles. Nowadays, several methods have been developed to determine the conditions under which cryptic genes are activated, in an attempt to induce these silenced biosynthetic pathways. Read More

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http://dx.doi.org/10.1002/mrc.4874DOI Listing

Computational H NMR: Part 1. Theoretical background.

Authors:
Leonid B Krivdin

Magn Reson Chem 2019 Apr 8. Epub 2019 Apr 8.

A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033, Irkutsk, Russia.

This is the first one of the three closely interrelated reviews to be published in Magnetic Resonance in Chemistry dealing with accordingly theoretical background, chemical applications and biochemical studies of and by means of computational H NMR. Presented in the first part of the review is a general outline of the modern theoretical methods and accuracy factors of computational H NMR involving locally dense basis set schemes, solvent effects, vibrational corrections, and relativistic effects performed at the DFT and/or non-empirical levels. This review is dedicated to Professor Stephan Sauer in view of his invaluable contribution to the field of computational NMR. Read More

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http://dx.doi.org/10.1002/mrc.4873DOI Listing
April 2019
1 Read

Synthesis of new cyano-substituted analogues of Tröger's bases from bromo-derivatives. A stereochemical dependence of long-range ( J , n = 4, 5, and 6) proton-proton and proton-carbon ( J , n = 1, 2, 3, 4, and 5) coupling constants of these compounds.

Magn Reson Chem 2019 Apr 2. Epub 2019 Apr 2.

Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506-6045, USA.

A free-catalyst microwave-assisted cyanation of brominated Tröger's base derivatives (2a-f) is reported. The procedure is simple, efficient and clean affording the nitrile compounds (3a-e, I) in very good yields. Complete assignment of H and C chemical shifts of 2a-f, I and 3a-d, I was achieved using gradient selected 1D NMR techniques (1D zTOCSY, PSYCHE, DPFGSE NOE and DEPT), homonuclear 2D NMR techniques (gCOSY, zTOCSY), and heteronuclear 2D NMR techniques (gHSQCAD/or pure-shift gHSQCAD, gHMBCAD, bsHSQCNOESY, and gHSQCAD-TOCSY) with adiabatic pulses. Read More

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http://dx.doi.org/10.1002/mrc.4872DOI Listing
April 2019
1 Read

Very low-temperature dynamic Si NMR study of the conformational equilibrium of (1,1'-phenyl-1,1'-silacyclohex-1-yl)disiloxane.

Magn Reson Chem 2019 Mar 23. Epub 2019 Mar 23.

A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russian Federation.

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http://dx.doi.org/10.1002/mrc.4870DOI Listing

NMR studies of new heterocycles tethered to purine moieties with anticancer activity.

Magn Reson Chem 2019 Mar 23. Epub 2019 Mar 23.

Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, Granada, Spain.

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http://dx.doi.org/10.1002/mrc.4871DOI Listing

NMR Crystallography.

Authors:
Maria Baias

Magn Reson Chem 2019 May;57(5):166

New York University Abu Dhabi, United Arab Emirates.

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http://dx.doi.org/10.1002/mrc.4868DOI Listing
May 2019
2 Reads

Structural and dynamical aspects of PEG/LiClO in solvent-mixtures via NMR spectroscopy.

Magn Reson Chem 2019 Mar 18. Epub 2019 Mar 18.

Department of Physical Sciences, Indian Institute of Science Education and Research, Mohali, 140306, India.

Motivated by the potential usefulness of PEG/Li salt mixtures in several industrial applications, the structure and dynamics of PEG/LiClO mixtures has been investigated in D O and its mixtures with CD CN and DMSO-D6, in a series of PEG-based polymers with a wide variation in their molecular weights. H NMR chemical shifts, T /T relaxation rates, pulsed field gradient (PFG) NMR diffusion experiments, and 2D-HOESY NMR studies have been performed to understand the structural and dynamical aspects of these mixtures. Increasing the temperature of the medium results in a significant perturbation in the H-bonded structure of PEG in its PEG/LiClO /D O mixtures as observed from the increase in chemical shifts. Read More

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http://dx.doi.org/10.1002/mrc.4867DOI Listing

Exploring the Crystallinity of Different Powder Sugars Through Solid Echo and Magic Sandwich Echo Sequences.

Magn Reson Chem 2019 Mar 14. Epub 2019 Mar 14.

Volga State University of Technology, Dept. of Phys., Yoshkar-Ola, Mari El, Russian Federation.

Time domain NMR (TD-NMR) techniques are frequently used in polymer, pharmaceutical and food industries as they offer rapid experimentation and generally do not require any considerable preliminary sample preparation. Detection of solid and liquid fractions in a sample is possible with the Free Induction Decay (FID). However, for the classical FID sequence that consists of a single pulse followed by relaxation decay acquisition, the dead time of the probe (ring-out of resonance circuitry) occurs and varies between 5-15 μs for standard 10 mm tubes. Read More

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http://dx.doi.org/10.1002/mrc.4866DOI Listing

NMR study of fresh cut salads: influence of temperature and storage time on leaf structure and water distribution in escarole.

Magn Reson Chem 2019 Mar 14. Epub 2019 Mar 14.

Irstea, UR OPAALE, 17 Avenue de Cucillé-CS 64427, F-35044, Rennes, France.

Consumption of fresh-cut vegetables has rapidly increased over the past decades. Among salads, escarole is one of the most popular varieties. Specific packaging limits gas exchange and consequently water loss and bacterial respiration, increasing the shelf life of salads. Read More

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http://dx.doi.org/10.1002/mrc.4865DOI Listing

Magnetic resonance studies of copper (II) sorbitol complex, in solution, reveals a supramolecular structure compatible to the crystal structure.

Magn Reson Chem 2019 Mar 13. Epub 2019 Mar 13.

Embrapa Instrumentação, Rua XV de novembro, 1452, 13560-970, São Carlos, SP, Brasil.

Although the Cu -Sorbitol complex [Cu -Sorb] structure in crystalline state has been determined by X rays it is not known in solution, where most studies of this complex is performed. Therefore, the goal of this work was to obtain information about the structure of this complex in aqueous solution using nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies. The magnetic resonance (MR) results indicate that the complex is formed at approximately pH 12. Read More

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http://dx.doi.org/10.1002/mrc.4863DOI Listing

A Non-destructive and Non-invasive Method to Determine Water Content in Lyophilized Proteins using Low field Time Domain NMR.

Magn Reson Chem 2019 Mar 12. Epub 2019 Mar 12.

Bristol-Myers Squibb, Drug Product Science and Technology, New Brunswick, New Jersey, 08903.

Determining the moisture content in lyophilized solids is a fundamental step towards predicting the quality and stability of lyophilized products, but conventional methods are time-consuming, invasive and destructive. High levels of residual moisture in a lyophilized product can lead to cake collapse, product degradation, and reduced shelf life. The aim of this study was to develop a fast, non-invasive, non-destructive and inexpensive method for determining the moisture content in a lyophilized monoclonal antibody (mAb) formulation using benchtop low-field time-domain nuclear magnetic resonance (TD NMR) spectroscopy. Read More

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http://dx.doi.org/10.1002/mrc.4864DOI Listing
March 2019
1 Read

SpinStudioJ: A cross-platform NMR data acquisition and processing workbench based on a plug-in architecture.

Authors:
Zao Liu Zhiwei Chen

Magn Reson Chem 2019 Mar 29. Epub 2019 Mar 29.

Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Research, Xiamen University, Xiamen, China.

Flexibility and extensibility are important issues in the design of nuclear magnetic resonance (NMR) software, as these determine the ability to integrate a variety of continuously evolving data acquisition and processing methods. Here, SpinStudioJ is introduced. It is an NMR data acquisition and processing workbench with a plug-in-based architecture. Read More

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http://dx.doi.org/10.1002/mrc.4862DOI Listing
March 2019
3 Reads

Rheo-NMR in food science - recent opportunities.

Magn Reson Chem 2019 Mar 10. Epub 2019 Mar 10.

SCPS, Victoria University of Wellington, Wellington, 6140, New Zealand.

For over 25 years, Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) techniques have been used to study materials under mechanical deformation. Collectively these methods are referred to as Rheo-NMR. In many cases it provides spatially and temporally resolved maps of NMR spectra, intrinsic NMR parameters (such as relaxation times) or motion (such as diffusion or flow). Read More

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http://dx.doi.org/10.1002/mrc.4861DOI Listing

Early stages of fat crystallisation evaluated by low field NMR and Small-Angle X-ray Scattering.

Magn Reson Chem 2019 Mar 6. Epub 2019 Mar 6.

School of Physics and Astronomy, University of Leeds, LS2 9JT, Leeds, UK.

Low field time-domain NMR (20 MHz) is commonly used in the studies of fats in the form of solid fat content (SFC) measurements. However, it has the disadvantage of low sensitivity to small amounts of crystalline material (0.5%), thus often incorrectly determining crystallisation induction times. Read More

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http://dx.doi.org/10.1002/mrc.4860DOI Listing
March 2019
1 Read

Optimal flip angle for robust practical quantitative NMR measurement using a fixed pulse length.

Magn Reson Chem 2019 Feb 26. Epub 2019 Feb 26.

Global Discovery Chemistry, Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, USA.

NMR quantification has been traditionally performed by using internal standards. Although methods using external reference in NMR quantification have been developed, the major obstacles in using external referencing method are the measurement deviations associated with changing sample conditions and the requirement of pulse width calibration for every sample in order to compensate these errors. The calibration process is time consuming and in some cases impossible. Read More

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http://dx.doi.org/10.1002/mrc.4859DOI Listing
February 2019

Single-shot measurement of solids and liquids T values by a small-angle flip-flop pulse sequence.

Magn Reson Chem 2019 Feb 23. Epub 2019 Feb 23.

Instituto de Macromoléculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Av. Horácio Macedo, 2.030, 21941-598, Rio de Janeiro, Brazil.

We propose the small-angle flip-flop (SAFF) pulse sequence as an alternative procedure for the rapid measurement of the H spin-lattice relaxation time in the laboratory frame (T ) of solid and liquid substances, in a time-domain NMR (TD-NMR) experiment. Based on the original flip-flop pulse sequence, this technique allows the fast estimation of T values of samples that require minutes to hours of acquisition time if traditional pulse sequences are employed. We have applied SAFF to different substances, with T ranging from microseconds up to seconds, including natural clays, polymers and organic and inorganic solvents. Read More

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http://dx.doi.org/10.1002/mrc.4858DOI Listing
February 2019
4 Reads

An evaluation of kefir grain size with magnetic resonance imaging to observe the fermentation of milk.

Magn Reson Chem 2019 Feb 22. Epub 2019 Feb 22.

School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.

Kefirian milk is a fermented beverage consumed worldwide. Originally produced in animal skins, it is now prepared both industrially and at home by adding symbiotic cultures of bacteria and yeast known as kefir grains to fresh milk. There is significant literature on the biological aspects of this process but little focus on the fermentation effects on the bulk milk as a function of the grain morphology. Read More

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http://dx.doi.org/10.1002/mrc.4853DOI Listing
February 2019
1 Read

Low field NMR for quality monitoring of 3D printed surimi from cod by-products: Effects of the pH-shift method compared with conventional washing.

Magn Reson Chem 2019 Feb 21. Epub 2019 Feb 21.

Matís ohf, Food and Biotech R&D, Research and Innovation, Reykjavik, Iceland.

Implementation of three-dimensional (3D) food printing and novel analytics can reduce food waste and increase utilization of seafood by-products. Low field nuclear magnetic resonance (LF-NMR) and chemometrics were used to investigate the printability and characteristics of surimi pastes from cod by-products as affected by different processing methods (the pH-shift method vs. conventional washing), addition of salt (0, 1. Read More

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http://dx.doi.org/10.1002/mrc.4855DOI Listing
February 2019
1 Read

Low-field NMR for quality control on oils.

Magn Reson Chem 2019 Feb 20. Epub 2019 Feb 20.

Institute for Mechanical Engineering and Mechanics, Karlsruher Institute of Technology (KIT), Karlsruhe, Germany.

Oil is a prominent, but multifaceted material class with a wide variety of applications. Technical oils, crude oils as well as edibles are main subclasses. In this review, the question is addressed how low-field NMR can contribute in oil characterization as an analytical tool, mainly with respect to quality control. Read More

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http://dx.doi.org/10.1002/mrc.4856DOI Listing
February 2019

H and C NMR data, occurrence, biosynthesis and biological activity of Piper amides.

Magn Reson Chem 2019 Feb 19. Epub 2019 Feb 19.

Centro de Investigaciones Químicas, IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, México.

Alkamides are the major and characteristic chemical compounds of the plants belonging to the Piper genus. These compounds are responsible for the flavor of pepper spices and for its broad use in cuisine across many regions of the world. Humans are in contact every day with these substances, which additionally show a broad variety of pharmacological activities, making them an important research target. Read More

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http://dx.doi.org/10.1002/mrc.4857DOI Listing
February 2019
1.179 Impact Factor

Influence of stereoelectronic effects on the J spin-spin coupling constant in fluorinated heterocyclic compounds.

Magn Reson Chem 2019 Feb 18. Epub 2019 Feb 18.

Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, Brazil.

The Perlin effect and its analog for fluorinated compounds (the fluorine Perlin-like effect) manifest on one-bond C─H (C─F for the fluorine Perlin-like effect) spin-spin coupling constants (SSCCs) in six-membered rings. These effects can be useful to probe the stereochemistry (axial or equatorial) of the C─H and C─F bonds, respectively. The origin of these effects has been debatable in the literature as being due to hyperconjugative interactions, dipolar effects, and induced current density. Read More

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http://dx.doi.org/10.1002/mrc.4854DOI Listing
February 2019

Nuclear magnetic relaxation and diffusion study of the ionic liquids 1-ethyl- and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide confined in porous glass.

Magn Reson Chem 2019 Feb 15. Epub 2019 Feb 15.

Department of Technical Physics II, Institute of Physics, Technische Universität Ilmenau, Ilmenau, Germany.

The molecular dynamics of the room-temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Bmim Tf2N) confined in porous glass is studied by nuclear magnetic resonance (NMR) relaxometry and diffusometry and is compared with the bulk dynamics over a wide temperature range. The molecular reorientation processes for anions and cations alike are found to be significantly affected by the presence of the glass interface at high temperatures. In this respect, the ionic liquid behaves similarly to polar liquids where proton NMR relaxation is governed by reorientations mediated by translational displacements (RMTDs). Read More

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http://dx.doi.org/10.1002/mrc.4852DOI Listing
February 2019

DFT computational schemes for N NMR chemical shifts of the condensed nitrogen-containing heterocycles.

Magn Reson Chem 2019 Feb 15. Epub 2019 Feb 15.

A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.

A systematic density functional theory (DFT) study of the accuracy factors (functionals, basis sets, and solvent effects) for the computation of N NMR chemical shifts has been performed in the series of condensed nitrogen-containing heterocycles. The behavior of the most representative functionals was examined based on the benchmark calculations of N NMR chemical shifts in the reference set of compounds. It was found that the best agreement with experiment was achieved with OLYP functional in combination with aug-pcS-3(N)//pc-2 locally dense basis set scheme providing mean absolute error of 5. Read More

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http://dx.doi.org/10.1002/mrc.4851DOI Listing
February 2019
1 Read

Identification of metabolites in coriander seeds (Coriandrum Sativum L.) aided by ultrahigh resolution total correlation NMR spectroscopy.

Magn Reson Chem 2019 Feb 14. Epub 2019 Feb 14.

Centre of Biomedical Research, SGPGIMS Campus, Lucknow, UP, India.

NMR is a fast method for obtaining a holistic snapshot of the metabolome and also offers quantitative information without separating the compounds present in a complex mixture. Identification of the metabolites present in a plant extract sample is a crucial step for all plant metabolomics studies. In the present work, we used various two dimensional (2D) NMR methods such as J-resolved NMR, total correlation spectroscopy (TOCSY), and heteronuclear single quantum coherence sensitivity enhanced NMR spectroscopy for the identification of 36 common metabolites present in Coriandrum sativum L. Read More

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http://dx.doi.org/10.1002/mrc.4850DOI Listing
February 2019
1 Read
1.179 Impact Factor

Monitoring dendrimer conformational transition using F and H O NMR.

Magn Reson Chem 2019 Feb 11. Epub 2019 Feb 11.

Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, 21201, USA.

The conformational transition of a fluorinated amphiphilic dendrimer is monitored by the H signal from water, alongside the F signal from the dendrimer. High-field NMR data (chemical shift δ, self-diffusion coefficient D, longitudinal relaxation rate R , and transverse relaxation rate R ) for both dendrimer ( F) and water ( H) match each other in detecting the conformational transition. Among all parameters for both nuclei, the water proton transverse-relaxation rate R ( H O) displays the highest relative scale of change upon conformational transition of the dendrimer. Read More

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http://dx.doi.org/10.1002/mrc.4849DOI Listing
February 2019

Reducing the computational cost of NMR crystallography of organic powders at natural isotopic abundance with the help of C- C dipolar couplings.

Magn Reson Chem 2019 May 11;57(5):256-264. Epub 2019 Mar 11.

Aix Marseille Univ, CNRS, ICR, Marseille, France.

Structure determination of functional organic compounds remains a formidable challenge when the sample exists as a powder. Nuclear magnetic resonance crystallography approaches based on the comparison of experimental and Density Functional Theory (DFT)-computed H chemical shifts have already demonstrated great potential for structure determination of organic powders, but limitations still persist. In this study, we discuss the possibility of using C- C dipolar couplings quantified on powdered theophylline at natural isotopic abundance with the help of dynamic nuclear polarization, to realize a DFT-free, rapid screening of a pool of structures predicted by ab initio random structure search. Read More

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http://doi.wiley.com/10.1002/mrc.4848
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http://dx.doi.org/10.1002/mrc.4848DOI Listing
May 2019
5 Reads

Phenylpropanoids, flavonoids, and terpenoids from Artemisia ordosica Krasch.

Magn Reson Chem 2019 Feb 7. Epub 2019 Feb 7.

College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, Tongliao, China.

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http://dx.doi.org/10.1002/mrc.4846DOI Listing
February 2019
2 Reads

Effect of d-psicose substitution on gelatin based soft candies: A TD-NMR study.

Magn Reson Chem 2019 Feb 7. Epub 2019 Feb 7.

Department of Food Engineering, Middle East Technical University, Ankara, Turkey.

Confectionary gels are considered as composite gel systems composed of high amount of sugar and gelling agent such as gelatin or starch. d-Psicose is classified as a type of rare sugar, which is a C-3 epimer of fructose and has 70% of the sweetness of sucrose with a caloric value of 0.39 kcal/g. Read More

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http://dx.doi.org/10.1002/mrc.4847DOI Listing
February 2019

A preliminary study of milk powder hydration using TEDSpiL continuous wave NMR.

Magn Reson Chem 2019 Feb 1. Epub 2019 Feb 1.

School of Science and Technology, Nottingham Trent University, Nottingham, UK.

Moisture content of foodstuffs are typically assessed by Titration or Near Infrared Spectroscopy, which are labour-intensive as a manual measurement or costly when automated. Magnetic resonance offers a method for moisture evaluation but is also normally costly. In this work, we revisit Look and Locker's "Tone Burst" experiment with a marginal oscillator to evaluate moisture content of powdered-skimmed milk subjected to increased humidity. Read More

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http://dx.doi.org/10.1002/mrc.4845DOI Listing
February 2019

Synthesis of α-fluoro-α,β-unsaturated esters monitored by 1D and 2D benchtop NMR spectroscopy.

Magn Reson Chem 2019 Jan 31. Epub 2019 Jan 31.

Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany.

For optimization and control of pharmaceutically and industrially important reactions, chemical information is required in real time. Instrument size, handling, and operation costs are important criteria to be considered when choosing a suitable analytical method apart from sensitivity and resolution. This present study explores the use of a robust and compact nuclear magnetic resonance (NMR) spectrometer to monitor the stereo-selective formation of α-fluoro-α,β-unsaturated esters from α-fluoro-β-keto esters via deprotonation and deacylation in real time. Read More

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http://dx.doi.org/10.1002/mrc.4843DOI Listing
January 2019

H- C HMBC NMR experiments as a structural and analytical tool for the characterization of elusive trans/cis hydroperoxide isomers from oxidized unsaturated fatty acids in solution.

Magn Reson Chem 2019 Apr 26;57(4):S69-S74. Epub 2019 Feb 26.

H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.

The radical-dependent oxidation of unsaturated fatty acids is a fundamental reaction in lipid chemistry, biochemistry, and technology. We report herein the first successful application of H- C HMBC NMR experiment for the identification and quantification of complex and minor (3.9% to 0. Read More

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http://dx.doi.org/10.1002/mrc.4844DOI Listing

Determination of the N chemical shift anisotropy in natural abundance samples by proton-detected 3D solid-state NMR under ultrafast MAS of 70 kHz.

Magn Reson Chem 2019 Jan 26. Epub 2019 Jan 26.

RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa, Japan.

Chemical shift anisotropy (CSA) is a sensitive probe of electronic environment at a nucleus, and thus, it offers deeper insights into detailed structural and dynamic properties of different systems, for example, chemical, biological, and materials. Over the years, massive efforts have been made to develop recoupling methods that reintroduce CSA interaction under magic angle spinning (MAS) conditions. Most of them require slow or moderate MAS (≤20 kHz) and isotopically enriched samples. Read More

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http://dx.doi.org/10.1002/mrc.4841DOI Listing
January 2019
1 Read

Water and oil signal assignment in low-moisture mozzarella as determined by time-domain NMR T relaxometry.

Magn Reson Chem 2019 Jan 24. Epub 2019 Jan 24.

Particle and Interfacial Technology Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.

A time-domain H nuclear magnetic resonance relaxometry method was elaborated for the rapid microstructural characterization of mozzarella cheese. For this purpose, there is a strong need to know how the experimentally determined T relaxation time distribution can be related to specific constituents in mozzarella. In this study, a detailed investigation is offered for fresh and aged low-moisture mozzarella cheese, often applied as a pizza cheese, by application of both a conventional Carr-Purcell-Meiboom-Gill (CPMG) sequence and a free-induction decay CPMG (FID-CPMG) sequence. Read More

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http://doi.wiley.com/10.1002/mrc.4842
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http://dx.doi.org/10.1002/mrc.4842DOI Listing
January 2019
2 Reads

NMR-based differentiation of conventionally from organically produced chicken eggs in Germany.

Magn Reson Chem 2019 Jan 24. Epub 2019 Jan 24.

Department of Food Chemistry and Phytochemistry Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.

Both the German and European organic food markets are growing fast, and there is also a rising demand for organic chicken eggs. Consumers are willing to pay higher prices for organic eggs produced in an animal-appropriate environment considering animal welfare. Strict labelling requirements do not prevent chicken eggs from being a subject of food fraud. Read More

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http://dx.doi.org/10.1002/mrc.4838DOI Listing
January 2019
14 Reads

Practical aspects of the simultaneous collection of COSY and TOCSY spectra.

Magn Reson Chem 2019 Apr 27;57(4):S85-S94. Epub 2019 Feb 27.

Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.

The practical aspects of some NMR experiments designed for the simultaneous acquisition of 2D COSY and 2D TOCSY spectra are presented and discussed. Several techniques involving afterglow-based, coherence transfer pathway (CTP)-based, and NMR by Ordered Acquisition using H-detection (NOAH)-based strategies for the collection of different free-induction signal decays (FIDs) within the same scan are evaluated and compared. These methods offer a faster recording of these spectra in small-molecule NMR when sensitivity is not a limiting factor, with a reduction in spectrometer time about 45-60% when compared with the conventional sequential acquisition of the parent experiments. Read More

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http://dx.doi.org/10.1002/mrc.4835DOI Listing

H and C NMR reassignment of some chemical shifts of lantanilic acid and camaric acid.

Magn Reson Chem 2019 Jan 24. Epub 2019 Jan 24.

Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, México.

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http://dx.doi.org/10.1002/mrc.4839DOI Listing
January 2019

Exploring the tumour extracellular matrix by in vivo Fast Field Cycling relaxometry after the administration of a Gadolinium-based MRI contrast agent.

Magn Reson Chem 2019 Jan 24. Epub 2019 Jan 24.

Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.

H Fast Field Cycling NMR (FFC-NMR) relaxometry is proposed as a powerful method to investigate tumour stroma in vivo upon the administration of a Gd-based contrast agent. To perform this study, an FFC-NMR equipment endowed with a wide bore magnet was used for the acquisition of Nuclear Magnetic Resonance Dispersion profiles on healthy muscle and tumour tissue in living mice. At magnetic field strengths < of ca. Read More

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http://doi.wiley.com/10.1002/mrc.4837
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http://dx.doi.org/10.1002/mrc.4837DOI Listing
January 2019
10 Reads

Fat crystals: A tool to inhibit molecular transport in W/O/W double emulsions.

Magn Reson Chem 2019 Jan 22. Epub 2019 Jan 22.

Particle and Interfacial Technology Group, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.

Water-in-oil-in-water (W/O/W) double emulsions are a promising technology for encapsulation applications of water soluble compounds with respect to functional food systems. Yet molecular transport through the oil phase is a well-known problem for liquid oil-based double emulsions. The influence of network crystallization in the oil phase of W/O/W globules was evaluated by NMR and laser light scattering experiments on both a liquid oil-based double emulsion and a solid fat-based double emulsion. Read More

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http://doi.wiley.com/10.1002/mrc.4840
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http://dx.doi.org/10.1002/mrc.4840DOI Listing
January 2019
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Regularized inversion of the Laplace transform for series of experiments.

Magn Reson Chem 2019 Jan 22. Epub 2019 Jan 22.

Institute of Concrete Structures and Building Materials, Karlsruhe Institute of Technology, Karlsruhe, Germany.

Not only in low-field nuclear magnetic resonance, Laplace inversion is a relevant and challenging topic. Considerable conceptual and technical progress has been made, especially for the inversion of data encoding two decay dimensions. Distortion of spectra by overfitting of even moderate noise is counteracted requiring a priori smooth spectra. Read More

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http://dx.doi.org/10.1002/mrc.4836DOI Listing
January 2019
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Identification of markers of thermal processing ("roasting") in aqueous extracts of Coffea arabica L. seeds through NMR fingerprinting and chemometrics.

Magn Reson Chem 2019 Jan 21. Epub 2019 Jan 21.

UMR 1145, AgroParisTech, INRA, Université Paris-Saclay, Massy, France.

Roasting of Coffea arabica L. seeds gives rise to chemical reactions that produce more than 800 compounds, some being responsible for the desired organoleptic properties for which the beverage called "coffee" is known. In the industry, the "roasting profile," that is, the times and temperatures applied, is key to influence the composition of roasted coffee beans and the flavour of the beverage made from them. Read More

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http://dx.doi.org/10.1002/mrc.4834DOI Listing
January 2019
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Full H and C NMR spectral assignment of conjugated valerolactone metabolites isolated from urine of black tea consumers by means of SPE-prepLC-MS-LC-MS-NMR.

Magn Reson Chem 2019 Jan 18. Epub 2019 Jan 18.

Spectroscopy & Imaging, Unilever Research and Development Vlaardingen, Vlaardingen, The Netherlands.

The health benefits of black tea have been linked to polyphenol metabolites that target specific modes of action in the human body. A major bottleneck in unravelling the underlying mechanisms is the preparative isolation of these metabolites, which hampers their structural elucidation and assessment of in vitro bioactivity. A solid phase extraction (SPE)-preparative liquid chromatography (prepLC)-MS-LC-MS-NMR workflow was implemented for preparative isolation of conjugated valerolactone metabolites of catechin-based polyphenols from urine of black tea consumers. Read More

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http://dx.doi.org/10.1002/mrc.4833DOI Listing
January 2019

Effect of long-term heat exposure on rheological and intrinsic water characteristics of bone-derived beef stocks.

Magn Reson Chem 2019 Jan 15. Epub 2019 Jan 15.

Department of Food Science, Research Centre Aarslev, Aarhus University, Aarslev, Denmark.

Bone-derived protein stocks are used in food industry to enhance taste of soups, sauces, and a range of other products. Both during commercial manufacturing and when used for culinary purposes, the stocks may be exposed to high temperatures for an extended time period. The present study investigated the effect of retention at 90°C for 0, 3, 6, 9, 24, 48, 72, and 168 hr on the functional attributes of concentrated bone-derived beef stocks (57% Dry matter (DM)). Read More

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http://dx.doi.org/10.1002/mrc.4831DOI Listing
January 2019
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QSAR studies of phenylhydrazine-substituted tetronic acid derivatives based on the H NMR and C NMR chemical shifts.

Magn Reson Chem 2019 Jan 11. Epub 2019 Jan 11.

Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing, China.

The quantitative structure-activity relationship models of 40 phenylhydrazine-substituted tetronic acid derivatives were established between the H nuclear magnetic resonance (NMR) and C NMR chemical shifts and the antifungal activity against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis, and Colletotrichum capsici. The models were validated by R, R , R , variance inflation factor, F, and P values testing and residual analysis. It was concluded from the models that the C NMR chemical shifts of C8, C10, C7, and the H NMR chemical shifts of Ha contributed positively to the activity against Fusarium graminearum, Botrytis cinerea, Colletotrichum capsici, and Rhizoctonia cerealis, respectively. Read More

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http://dx.doi.org/10.1002/mrc.4830DOI Listing
January 2019
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Characterization of gluten-free bread crumb baked at atmospheric and reduced pressures using TD-NMR.

Magn Reson Chem 2019 Jan 8. Epub 2019 Jan 8.

Irstea, OPAALE, IRM Food team, Rennes, France.

This research aimed to study the effects of using a partial vacuum for bread baking on macromolecules and water distribution in gluten-free bread. Bread baking under partial vacuum results in greater oven rise and a larger gas fraction in the crumb. Because water's boiling point decreases under reduced pressure, it was expected that its distribution within the dough and its interactions with the others dough's constituents (mainly starch) would differ from those in bread baked under atmospheric pressure. Read More

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http://dx.doi.org/10.1002/mrc.4829DOI Listing
January 2019
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Calculations of C NMR chemical shifts and F-C coupling constants of ciprofloxacin.

Magn Reson Chem 2019 Apr 31;57(4):S75-S84. Epub 2019 Jan 31.

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University "Ss. Cyril and Methodius", Skopje, Republic of Macedonia.

Ciprofloxacin is a widely used fluoroquinolone antibiotic. In this work, a comprehensive evaluation of MP2 and DFT with different functionals and basis sets was carried out to select the most suitable level of theory for the study of the NMR properties of ciprofloxacin. Their relative predictive capabilities were evaluated comparing the theoretically predicted and experimental spectral data. Read More

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http://dx.doi.org/10.1002/mrc.4827DOI Listing

In situ measurement of deposit layer formation during skim milk filtration by MRI.

Magn Reson Chem 2019 Jan 3. Epub 2019 Jan 3.

Karlsruhe Institute of Technology (KIT), Institute of Mechanical Process Engineering and Mechanics, Karlsruhe, Germany.

Filtration and separation via membranes are key processes in food processing. One major application of membrane filtration is in the dairy industry, aiming for the separation of different milk proteins. The various chemical components of milk possess different physiochemical properties and can be used most effectively in food processing if they are separately available and remain in their native state. Read More

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http://dx.doi.org/10.1002/mrc.4826DOI Listing
January 2019

Application of proton field-cycling NMR relaxometry for studying translational diffusion in simple liquids and polymer melts.

Magn Reson Chem 2019 Jan 2. Epub 2019 Jan 2.

Experimentalphysik and Nordbayerisches NMR-Zentrum, Universität Bayreuth, Bayreuth, Germany.

With the availability of commercial field-cycling relaxometers together with progress of home-built instruments nuclear magnetic resonance relaxometry has gained new momentum as a method of investigating the dynamics in viscous liquids and polymer melts. The method provides the frequency dependence of the spin-lattice relaxation rate. In the case of protons, one distinguishes intramolecular and intermolecular relaxation pathways. Read More

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http://dx.doi.org/10.1002/mrc.4823DOI Listing
January 2019
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A theoretical NMR study of polymorphism in crystal structures of azoles and benzazoles.

Magn Reson Chem 2019 Jan 2. Epub 2019 Jan 2.

Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva, 3, Madrid, E-28006, Spain.

The NMR chemical shifts of two azoles and one benzazole whose crystal structures present polymorphism have been computed using the GIPAW approach. N and C nuclei have been studied. Statistical analysis of the computed C and N chemical shifts indicates that the GIPAW chemical shifts reproduce with a high degree of accuracy those experimentally reported. Read More

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http://dx.doi.org/10.1002/mrc.4824DOI Listing
January 2019