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Journal articles on the topic 'Relaxation processes in nuclear magnetic resonance molecules'

Author: Grafiati

Published: 17 September 2021

Last updated: 1 February 2022

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1

Foster, Richard J., Robin A. Damion, Thomas G. Baboolal, Stephen W. Smye, and Michael E. Ries. "A nuclear magnetic resonance study of water in aggrecan solutions." Royal Society Open Science 3, no. 3 (2016): 150705. http://dx.doi.org/10.1098/rsos.150705.

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Aggrecan, a highly charged macromolecule found in articular cartilage, was investigated in aqueous salt solutions with proton nuclear magnetic resonance. The longitudinal and transverse relaxation rates were determined at two different field strengths, 9.4 T and 0.5 T, for a range of temperatures and aggrecan concentrations. The diffusion coefficients of the water molecules were also measured as a function of temperature and aggrecan concentration, using a pulsed field gradient technique at 9.4 T. Assuming an Arrhenius relationship, the activation energies for the various relaxation processes

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2

Sellies, Lisanne, Ruud L. E. G. Aspers, and Marco Tessari. "Determination of hydrogen exchange and relaxation parameters in PHIP complexes at micromolar concentrations." Magnetic Resonance 2, no. 1 (2021): 331–40. http://dx.doi.org/10.5194/mr-2-331-2021.

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Abstract. Non-hydrogenative para-hydrogen-induced polarization (PHIP) is a fast, efficient and relatively inexpensive approach to enhance nuclear magnetic resonance (NMR) signals of small molecules in solution. The efficiency of this technique depends on the interplay of NMR relaxation and kinetic processes, which, at high concentrations, can be characterized by selective inversion experiments. However, in the case of dilute solutions this approach is clearly not viable. Here, we present alternative PHIP-based NMR experiments to determine hydrogen and hydride relaxation parameters as well as t

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3

Yagihara, Shin, Hironobu Saito, Hironori Sugimoto, et al. "Evaluation of water structures in cotton cloth by fractal analysis with broadband dielectric spectroscopy." Journal of Materials Science 56, no. 31 (2021): 17844–59. http://dx.doi.org/10.1007/s10853-021-06419-7.

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AbstractBroadband dielectric spectroscopy measurements were performed on naturally dried cotton cloth, and a recently developed analytical technique for fractal analysis of water structures was applied to obtain existential states and locations of water molecules in the material. Three relaxation processes observed in GHz, MHz, and kHz frequency regions were attributed to dynamic behaviors of hydrogen bonding networks (HBNs) of water and interacting molecules, polymer chains with interacting ion and water molecules, and ions restricted on the interfaces of larger structures, respectively. Wate

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4

Rampino, Sergio, Mirco Zerbetto, and Antonino Polimeno. "Stochastic Modelling of 13C NMR Spin Relaxation Experiments in Oligosaccharides." Molecules 26, no. 9 (2021): 2418. http://dx.doi.org/10.3390/molecules26092418.

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A framework for the stochastic description of relaxation processes in flexible macromolecules including dissipative effects has been recently introduced, starting from an atomistic view, describing the joint relaxation of internal coordinates and global degrees of freedom, and depending on parameters recoverable from classic force fields (energetics) and medium modelling at the continuum level (friction tensors). The new approach provides a rational context for the interpretation of magnetic resonance relaxation experiments. In its simplest formulation, the semi-flexible Brownian (SFB) model h

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5

Hronský, V., J. Murín, and J. Uhrin. "Dynamic-mechanical and nuclear magnetic resonance study of relaxation processes in ultra-high molecular weight polyethylene fibres." Czechoslovak Journal of Physics 56, no. 3 (2006): 289–302. http://dx.doi.org/10.1007/s10582-006-0089-3.

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6

Martini, Silvia, Claudia Bonechi, Alberto Foletti, and Claudio Rossi. "Water-Protein Interactions: The Secret of Protein Dynamics." Scientific World Journal 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/138916.

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Water-protein interactions help to maintain flexible conformation conditions which are required for multifunctional protein recognition processes. The intimate relationship between the protein surface and hydration water can be analyzed by studying experimental water properties measured in protein systems in solution. In particular, proteins in solution modify the structure and the dynamics of the bulk water at the solute-solvent interface. The ordering effects of proteins on hydration water are extended for several angstroms. In this paper we propose a method for analyzing the dynamical prope

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7

Lim, Ae Ran. "Molecular dynamics of hybrid halide perovskite (CH3NH3)2CuX4 (X = Br and Cl) determined by nuclear magnetic resonance relaxation processes." Solid State Sciences 96 (October 2019): 105955. http://dx.doi.org/10.1016/j.solidstatesciences.2019.105955.

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8

Yamada, Shunji, Atsushi Kurotani, Eisuke Chikayama, and Jun Kikuchi. "Signal Deconvolution and Noise Factor Analysis Based on a Combination of Time–Frequency Analysis and Probabilistic Sparse Matrix Factorization." International Journal of Molecular Sciences 21, no. 8 (2020): 2978. http://dx.doi.org/10.3390/ijms21082978.

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Nuclear magnetic resonance (NMR) spectroscopy is commonly used to characterize molecular complexity because it produces informative atomic-resolution data on the chemical structure and molecular mobility of samples non-invasively by means of various acquisition parameters and pulse programs. However, analyzing the accumulated NMR data of mixtures is challenging due to noise and signal overlap. Therefore, data-cleansing steps, such as quality checking, noise reduction, and signal deconvolution, are important processes before spectrum analysis. Here, we have developed an NMR measurement informat

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9

Weisenberger, L. A., and J. L. Koenig. "NMR Imaging of Solvent Diffusion in Polymers." Applied Spectroscopy 43, no. 7 (1989): 1117–26. http://dx.doi.org/10.1366/0003702894203453.

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Nuclear magnetic resonance (NMR) imaging is sensitive to the mobile protons of solvent molecules and, as such, is well suited for studying the solvent diffusion in polymers. The fundamentals of NMR imaging are described, providing a platform for application of NMR imaging to diffusion processes in polymers. The constraints on the imaging experiment imposed by the diffusion process are discussed with respect to sample geometry and the rate of diffusion. A fast imaging scheme known as FLASH is described as an alternative method which reduces the influence of the diffusion rate and NMR relaxation

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10

Anthis, Nicholas J., and G. Marius Clore. "Visualizing transient dark states by NMR spectroscopy." Quarterly Reviews of Biophysics 48, no. 1 (2015): 35–116. http://dx.doi.org/10.1017/s0033583514000122.

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AbstractMyriad biological processes proceed through states that defy characterization by conventional atomic-resolution structural biological methods. The invisibility of these ‘dark’ states can arise from their transient nature, low equilibrium population, large molecular weight, and/or heterogeneity. Although they are invisible, these dark states underlie a range of processes, acting as encounter complexes between proteins and as intermediates in protein folding and aggregation. New methods have made these states accessible to high-resolution analysis by nuclear magnetic resonance (NMR) spec

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11

Salvi, Nicola, Anton Abyzov, and Martin Blackledge. "Solvent-dependent segmental dynamics in intrinsically disordered proteins." Science Advances 5, no. 6 (2019): eaax2348. http://dx.doi.org/10.1126/sciadv.aax2348.

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Protein and water dynamics have a synergistic relationship, which is particularly important for intrinsically disordered proteins (IDPs), although the details of this coupling remain poorly understood. Here, we combine temperature-dependent molecular dynamics simulations using different water models with extensive nuclear magnetic resonance (NMR) relaxation to examine the importance of distinct modes of solvent and solute motion for the accurate reproduction of site-specific dynamics in IDPs. We find that water dynamics play a key role in motional processes internal to “segments” of IDPs, stre

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12

Nelson, Madison L., Joelle E. Romo, Stephanie G. Wettstein, and Joseph D. Seymour. "Impact of Xylose on Dynamics of Water Diffusion in Mesoporous Zeolites Measured by NMR." Molecules 26, no. 18 (2021): 5518. http://dx.doi.org/10.3390/molecules26185518.

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Zeolites are known to be effective catalysts in biomass converting processes. Understanding the mesoporous structure and dynamics within it during such reactions is important in effectively utilizing them. Nuclear magnetic resonance (NMR) T2 relaxation and diffusion measurements, using a high-power radio frequency probe, are shown to characterize the dynamics of water in mesoporous commercially made 5A zeolite beads before and after the introduction of xylose. Xylose is the starting point in the dehydration into furfural. The results indicate xylose slightly enhances rotational mobility while

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13

Ribeiro, Ana C. F., and Miguel A. Esteso. "Transport Properties for Pharmaceutical Controlled-Release Systems: A Brief Review of the Importance of Their Study in Biological Systems." Biomolecules 8, no. 4 (2018): 178. http://dx.doi.org/10.3390/biom8040178.

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: The goal of this work was to comprehensive study the transport properties of controlled-release systems for the safe and reliable delivery of drugs. Special emphasis has been placed on the measurement of the diffusion of drugs, alone or in combination with carrier molecules for enhanced solubility and facilitated transport. These studies have provided detailed comprehensive information—both kinetic and thermodynamic—for the design and operation of systems for the controlled release and delivery of drugs. Cyclodextrins are among the most important carriers used in these systems. The basis for

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14

Szutkowski, Kosma, Emilia Sikorska, Iulia Bakanovych, et al. "Structural Analysis and Dynamic Processes of the Transmembrane Segment Inside Different Micellar Environments—Implications for the TM4 Fragment of the Bilitranslocase Protein." International Journal of Molecular Sciences 20, no. 17 (2019): 4172. http://dx.doi.org/10.3390/ijms20174172.

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The transmembrane (TM) proteins are gateways for molecular transport across the cell membrane that are often selected as potential targets for drug design. The bilitranslocase (BTL) protein facilitates the uptake of various anions, such as bilirubin, from the blood into the liver cells. As previously established, there are four hydrophobic transmembrane segments (TM1–TM4), which constitute the structure of the transmembrane channel of the BTL protein. In our previous studies, the 3D high-resolution structure of the TM2 and TM3 transmembrane fragments of the BTL in sodium dodecyl sulfate (SDS)

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15

Hertkorn, N., M. Harir, B. P. Koch, B. Michalke, P. Grill, and P. Schmitt-Kopplin. "High field NMR spectroscopy and FTICR mass spectrometry: powerful discovery tools for the molecular level characterization of marine dissolved organic matter from the South Atlantic Ocean." Biogeosciences Discussions 9, no. 1 (2012): 745–833. http://dx.doi.org/10.5194/bgd-9-745-2012.

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Abstract. Non target high resolution organic structural spectroscopy of marine dissolved organic matter (DOM) isolated on 27 November 2008 by means of solid phase extraction (SPE) from four different depths in the South Atlantic Ocean off the Angola coast (3.1° E; −17.7° S; Angola basin) provided molecular level information of complex unknowns with unprecedented coverage and resolution. The sampling was intended to represent major characteristic oceanic regimes of general significance: 5 m (FISH; near surface photic zone), 48 m (FMAX; fluorescence maximum), 200 m (upper mesopelagic zone) and 5

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16

Reusser, Jolanda E., René Verel, Daniel Zindel, Emmanuel Frossard, and Timothy I. McLaren. "Identification of lower-order inositol phosphates (IP<sub>5</sub> and IP<sub>4</sub>) in soil extracts as determined by hypobromite oxidation and solution <sup>31</sup>P NMR spectroscopy." Biogeosciences 17, no. 20 (2020): 5079–95. http://dx.doi.org/10.5194/bg-17-5079-2020.

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Abstract. Inositol phosphates (IPs) are a major pool of identifiable organic phosphorus (P) in soil. However, insight into their distribution and cycling in soil remains limited, particularly of lower-order IP (IP5 and IP4). This is because the quantification of lower-order IP typically requires a series of chemical extractions, including hypobromite oxidation to isolate IP, followed by chromatographic separation. Here, for the first time, we identify the chemical nature of organic P in four soil extracts following hypobromite oxidation using solution 31P NMR spectroscopy and transverse relaxa

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17

Hertkorn, N., M. Harir, B. P. Koch, B. Michalke, and P. Schmitt-Kopplin. "High-field NMR spectroscopy and FTICR mass spectrometry: powerful discovery tools for the molecular level characterization of marine dissolved organic matter." Biogeosciences 10, no. 3 (2013): 1583–624. http://dx.doi.org/10.5194/bg-10-1583-2013.

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Abstract. High-performance, non-target, high-resolution organic structural spectroscopy was applied to solid phase extracted marine dissolved organic matter (SPE-DOM) isolated from four different depths in the open South Atlantic Ocean off the Angola coast (3° E, 18° S; Angola Basin) and provided molecular level information with extraordinary coverage and resolution. Sampling was performed at depths of 5 m (Angola Current; near-surface photic zone), 48 m (Angola Current; fluorescence maximum), 200 m (still above Antarctic Intermediate Water, AAIW; upper mesopelagic zone) and 5446 m (North Atla

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18

Zerbetto, Mirco, and Antonino Polimeno. "Multiscale modeling for interpreting nuclear magnetic resonance relaxation in flexible molecules." International Journal of Quantum Chemistry 116, no. 22 (2016): 1706–22. http://dx.doi.org/10.1002/qua.25215.

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19

Jin, Dan, Wu Yao, An Ming She, and Xiao Yan Liu. "Nuclear Magnetic Resonance Studies on Microstructure of Cement Pastes." Advanced Materials Research 177 (December 2010): 518–21. http://dx.doi.org/10.4028/www.scientific.net/amr.177.518.

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For water filled porous materials, the difference between the relaxation time of molecules at the pore surface and the relaxation time of molecules in the bulk fluid can be interpreted by a fast diffusion model. With this model, the nuclear magnetic resonance (NMR) can be applied to investigate the microstructure of cement pastes. The cement pastes we tested are two series, one is of same water to cement ratio (w/c=0.4) at different curing time (7d, 28d and 90d), the other is of different water to cement ratio (w/c=0.3, 0.4 and0.5, respectively) at the same curing day. Comparing results by NMR

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20

Wüthrich, Kurt. "Nuclear magnetic resonance – from molecules to man." Quarterly Reviews of Biophysics 19, no. 1-2 (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 t

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21

Клименок, К. Л., А. Ю. Демьянов, and О. Ю. Динариев. "Surface relaxation effect on nuclear magnetic resonance flow propagators." Numerical Methods and Programming (Vychislitel'nye Metody i Programmirovanie), no. 1(55) (March 13, 2018): 112–20. http://dx.doi.org/10.26089/nummet.v19r110.

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Статья посвящена развитию подхода, ранее предложенного авторами для численного моделирования ядерного магнитного резонанса (ЯМР) в пористых средах с учетом движения фаз. Более детально рассмотрено влияние граничных условий на контакте "пористая среда-порода" и релаксационных процессов, протекающих в объеме флюида, на функцию потокового пропагатора. С использованием численного моделирования на примерах течений в модельных и реальных пористых средах показана значимость этих процессов. Сделан вывод о необходимости их учета в лабораторных экспериментах и представлена методика оценки влияния значен

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22

Kjær, L., C. Thomsen, H. B. W. Larsson, O. Henriksen, and P. Ring. "Evaluation of biexponential relaxation processes by magnetic resonance imaging." Acta Radiologica 29, no. 4 (1988): 473–80. http://dx.doi.org/10.3109/02841858809175023.

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23

Kjær, L., C. Thomsen, H. B. W. Larsson, O. Henriksen, and P. Ring. "Evaluation of Biexponential Relaxation Processes by Magnetic Resonance Imaging." Acta Radiologica 29, no. 4 (1988): 473–79. http://dx.doi.org/10.1177/028418518802900418.

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Despite the complexity of biologic tissues, a monoexponential behaviour is usually assumed when estimating relaxation processes in vivo by magnetic resonance imaging (MRI). This study was designed to evaluate the potential of biexponential decomposition of T1 and T2 relaxation curves obtained at 1.5 tesla (T). Measurements were performed on a phantom of bicompartmental perspex boxes with combinations of different CuSO4 concentrations. T1 determination was based on a 12-points partial saturation inversion recovery pulse sequence. T2 determination was provided by a multiple spin echo sequence wi

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24

Paczwa, Mateusz, Aleksej A. Sapiga, Marcin Olszewski, Nikolaj Sergeev, and Aleksej V. Sapiga. "23Na Nuclear Magnetic Resonance Study of the Structure and Dynamic of Natrolite." Zeitschrift für Naturforschung A 70, no. 4 (2015): 295–300. http://dx.doi.org/10.1515/zna-2014-0371.

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AbstractThe temperature dependences of nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR spectra of 23Na nuclei in natrolite (Na2Al2Si3O10·2H2O) have been studied. The temperature dependences of the spin-lattice relaxation times T1 in natrolite have also been studied. It has been shown that the spin-lattice relaxation of the 23Na is governed by the electric quadrupole interaction with the crystal electric field gradients modulated by translational motion of H2O molecules in the natrolite pores. The dipolar interactions with paramagnetic impurities become significant as a rela

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25

Yang, D., and K. Nagayama. "Permeation of small molecules into the cavity of ferritin as revealed by proton nuclear magnetic resonance relaxation." Biochemical Journal 307, no. 1 (1995): 253–56. http://dx.doi.org/10.1042/bj3070253.

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The NMR relaxation technique was used to investigate the permeation of molecules into the cavity of ferritin. Spin-lattice relaxation times in the rotating frame of various probe molecules were measured for solutions of recombinant horse L-apoferritin without iron and horse spleen apoferritin with very small amounts of ferric ions. The results show that molecules larger than the size of the ferritin channels can pass through the channels into the ferritin interior, and that the maximum size of molecules for the permeation is smaller than maltotriose.

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26

Buist, Richard J., and Donald R. Eaton. "Rotating frame nuclear magnetic resonance experiments on metal complexes." Canadian Journal of Chemistry 65, no. 7 (1987): 1653–57. http://dx.doi.org/10.1139/v87-276.

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Measurements of the rate of nuclear magnetic relaxation in the rotating frame (T1ρ) have the potential to provide significant information not readily available by other nmr methods. Some applications to metal complex chemistry are described. The method has been applied to 59Co nmr and used to obtain 59Co–14N spin–spin coupling constants for the tris(ethylenediamine)cobalt(III) and hexanitrocobaltate(III) ions. The larger coupling constant in the latter compound is related to the different hybridization of the nitrogen atom. Proton T1ρ measurements on thiourea and its zinc complex have demonstr

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27

Kruk, Danuta, Elzbieta Masiewicz, Anna M. Borkowska, et al. "Dynamics of Solid Proteins by Means of Nuclear Magnetic Resonance Relaxometry." Biomolecules 9, no. 11 (2019): 652. http://dx.doi.org/10.3390/biom9110652.

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1H Nuclear magnetic resonance (NMR) relaxometry was exploited to investigate the dynamics of solid proteins. The relaxation experiments were performed at 37 °C over a broad frequency range, from approximately 10 kHz to 40 MHz. Two relaxation contributions to the overall 1H spin–lattice relaxation were revealed; they were associated with 1H–1H and 1H–14N magnetic dipole–dipole interactions, respectively. The 1H–1H relaxation contribution was interpreted in terms of three dynamical processes occurring on timescales of 10−6 s, 10−7 s, and 10−8 s, respectively. The 1H–14N relaxation contribution s

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28

Ashley, David L., Elizabeth R. Barnhart, Donald G. Patterson, and Robert H. Hill. "Identification of Polychlorinated Pyrenes and Pyrene-Addition Products Using Proton Nuclear Magnetic Resonance Techniques." Applied Spectroscopy 41, no. 7 (1987): 1194–99. http://dx.doi.org/10.1366/0003702874447428.

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Nuclear magnetic resonance (NMR) techniques are used to determine the chlorination pattern on a number of chlorinated pyrenes and pyrene-addition products. Determining chemical shifts, couplings, and longitudinal relaxation rates makes the unequivocal assignment of these molecules possible. Chlorination under the conditions described here were found to follow the normal orientation rules for pyrene. Spectral parameters obtained from these molecules are consistent enough to allow further application to unknown compounds. This should simplify assigning NMR spectra to other chlorinated pyrene sta

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29

Chazin, Walter J., Lawrence D. Colebrook, Brian R. Davis, I. Ross N. McCormick, and Stephen J. Johnson. "The stereochemistry of some 7-hydroxyindene dimers: applications of 1H nuclear magnetic resonance relaxation pathway analysis." Canadian Journal of Chemistry 63, no. 8 (1985): 2332–38. http://dx.doi.org/10.1139/v85-385.

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1H spin-lattice relaxation rates and nuclear Overhauser effect difference spectra have been measured (at 400 MHz) for six dimers derived from methyl-substituted 7-hydroxyindenes. Used in combination, these measurements identify the relaxation pathways available to all of the protons in the molecules. Analysis of these pathways has permitted assignment of all chemical shifts, and identification of the relative stereochemistry at all chiral centres.

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30

Skalerič, U., J. Dolinšek, J. Stepisnik, P. Cevc, and M. Schara. "NMR Imaging in Dentistry: Relaxation and Diffusion Studies." Advances in Dental Research 1, no. 1 (1987): 85–87. http://dx.doi.org/10.1177/08959374870010011901.

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Magnetic resonance imaging has been widely used for medical diagnosis in recent years. The knowledge of the proton spin-lattice relaxation time, T1, represents the basis for NMR imaging. In the present study, we measured T1 in saliva, gingival fluid, gingival blood, and inflamed gingiva by means of a pulsed NMR Fourier-transform spectrometer. From several measurements, we found the following average T1 values: in saliva, T1 = 2550 msec; in gingival fluid, T1 = 2085 msec; in gingival blood, T1 = 1515 msec; and in inflamed gingiva samples, T1 = 840 msec. In addition, electron paramagnetic resona

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31

Laupretre, Françoise, Claudine Noël, W. N. Jenkins, and Graham Williams. "Dielectric, nuclear magnetic resonance and electron spin resonance studies of relaxation processes in a liquid-crystalline polyester." Faraday Discuss. Chem. Soc. 79 (1985): 191–99. http://dx.doi.org/10.1039/dc9857900191.

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Ichikawa, Kazuhiko. "The effect of chemical exchange on energy relaxation processes in nuclear magnetic resonance spectroscopy." Journal of the Chemical Society, Faraday Transactions 2 82, no. 11 (1986): 1913. http://dx.doi.org/10.1039/f29868201913.

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Lewis, J. S., E. Tomchuk, and E. Bock. "A carbon-13 nuclear magnetic resonance relaxation study of the reentrant 60CB–80CB." Canadian Journal of Physics 69, no. 12 (1991): 1454–58. http://dx.doi.org/10.1139/p91-216.

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The carbon-13 spin-lattice relaxation times of the protonated ring carbons of octyloxycyanobiphenyl (80CB) in a 26 wt.% mixture of perdeuterated hexyloxycyanobiphenyl (60CB–d21) in 80CB are measured as a function of temperature at 22.63 MHz in the nematic (N), smectic A(SA), and reentrant nematic (RN) phases. The deuterium spectral densities of the ring deuterons of 60CB–d21 in the same sample were studied previously, and the diffusion coefficients [Formula: see text] and [Formula: see text] found in that study are used to calculate the theoretical carbon-13 relaxation times of the protonated

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34

Erdem, Özlen F., André Pampel, and Dieter Michel. "Slow Motion of Confined Molecules: NMR and Broadband Dielectric Spectroscopy Investigations." Journal of Nanoscience and Nanotechnology 8, no. 2 (2008): 887–93. http://dx.doi.org/10.1166/jnn.2008.d003.

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Nuclear magnetic resonance (NMR) and broadband dielectric spectroscopy are used to investigate the dynamics of small glass-forming molecules confined to restricted geometries. Ethylene glycol molecules are embedded in the supercages of NaX zeolites. The combined application of NMR and broadband dielectric spectroscopy advances the understanding of the slowing down of the motion near the glass transition temperature of these confined molecules. In combination with nuclear spin relaxation and nuclear magnetic resonance spectroscopy, dielectric relaxation studies on glass forming molecules allow

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35

Kjær, L., C. Thomsen, O. Henriksen, P. Ring, M. Stubgaard, and E. J. Pedersen. "Evaluation of Relaxation Time Measurements by Magnetic Resonance Imaging." Acta Radiologica 28, no. 3 (1987): 345–51. http://dx.doi.org/10.1177/028418518702800323.

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Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different concentrations of CuSO4 and correlating the calculated T1 and T2 values with reference values obtained by two spectrometers (corrected to MRI-proton frequency=64 MHz) we found a maximum deviation of about 10 per cent. Measurements performed on a large water phantom in order to evaluate the homogenei

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36

Lusceac, S. A., C. Gainaru, M. Vogel, C. Koplin, P. Medick, and E. A. Rössler. "Secondary Relaxation Processes in Polybutadiene Studied by2H Nuclear Magnetic Resonance and High-Precision Dielectric Spectroscopy." Macromolecules 38, no. 13 (2005): 5625–33. http://dx.doi.org/10.1021/ma050022b.

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37

Weller, Andreas, Sven Nordsiek, and Wolfgang Debschütz. "Estimating permeability of sandstone samples by nuclear magnetic resonance and spectral-induced polarization." GEOPHYSICS 75, no. 6 (2010): E215—E226. http://dx.doi.org/10.1190/1.3507304.

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Two techniques to estimate permeability are compared in this paper: nuclear magnetic resonance (NMR) and spectral-induced polarization (SIP). Both methods are based on relaxation processes. NMR records the relaxation of hydrogen nuclei after excitation in an external magnetic field. The phenomenon of induced polarization can be characterized by a relaxation of ions after excitation by an electric field. Hydrogen nuclei are concentrated in the pore water, the current flow is restricted to the pore space for most reservoir rocks, and permeability is related to the pore space geometry. Based on t

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38

Haida, Munetaka, Masahiro Yamamoto, Hideshi Matsumura, Yukito Shinohara, and Minoru Fukuzaki. "Intracellular and Extracellular Spaces of Normal Adult Rat Brain Determined from the Proton Nuclear Magnetic Resonance Relaxation Times." Journal of Cerebral Blood Flow & Metabolism 7, no. 5 (1987): 552–56. http://dx.doi.org/10.1038/jcbfm.1987.104.

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The nuclear magnetic resonance method was used to investigate the state of water molecules in normal rat brain tissue in vitro. The transverse magnetization decay curve (TMDC) of the fresh brain tissue of adult rats (8- or 10-weeks-old) was biexponential, which could be interpreted in terms of two distinct transverse relaxation times ( T2). Several factors that may affect the TMDC are discussed. It was concluded that the fast and slow components of T2 correspond to those of the water molecules of the intracellular and the extracellular spaces of normal rat brain tissue, respectively.

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Krieger, Ju H., A. R. Semenov, and G. N. Chekhova. "Investigation of the mobility of paraffin molecules in channel urea clathrates by nuclear magnetic resonance relaxation spectroscopy." Physics of the Solid State 43, no. 11 (2001): 2060–62. http://dx.doi.org/10.1134/1.1417179.

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Xiang, Tian‐xiang, Fang Liu, and David M. Grant. "Stochastic dynamics ofn‐nonane and related molecules in solution compared with nuclear magnetic resonance coupled relaxation times." Journal of Chemical Physics 95, no. 10 (1991): 7576–90. http://dx.doi.org/10.1063/1.461384.

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Ebifegha, M. E., R. F. Code, K. G. McNeill, and M. Szyjkowski. "Nuclear-magnetic-resonance determinations of fluorine content and relaxation times in bone powder." Canadian Journal of Physics 64, no. 3 (1986): 282–88. http://dx.doi.org/10.1139/p86-050.

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The detection of trace amounts of fluoride ions from ground rat-bone samples using a 27-MHz solid-state single-coil pulsed nuclear-magnetic-resonance (NMR) spectrometer is described. The fluorine content in the bone samples as determined from the amplitudes of the free-induction-decay (FID) signals is in good agreement with analyses based on standard chemical and neutron-activation techniques. The value of the spin-lattice relaxation time T1 is 1.46 ± 0.07 s in dry rat-bone powder and is slightly longer in wet bone powder depending on the water content. The contribution of cross-relaxation pro

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Wagner, Gerhard, Geoffrey Bodenhausen, Norbert Mueller, et al. "Exchange of two-spin order in nuclear magnetic resonance: separation of exchange and cross-relaxation processes." Journal of the American Chemical Society 107, no. 23 (1985): 6440–46. http://dx.doi.org/10.1021/ja00309a002.

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Joyce, Daryl C., Paul D. Hockings, Roy A. Mazucco, and Anthony J. Shorter. "1H-Nuclear magnetic resonance imaging of ripening 'Kensington Pride' mango fruit." Functional Plant Biology 29, no. 7 (2002): 873. http://dx.doi.org/10.1071/pp01150.

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Physicochemical gradients occur in mango mesocarp tissue during ripening. These gradients are reflected in water activity, which is non-uniform throughout the mesocarp. Signal intensity in proton magnetic resonance images (first echo, proton density and T2) for green-mature `Kensington Pride' mesocarp tissue was highest near the endocarp and lowest near the exocarp. Relative signal intensity increased in the middle mesocarp as ripening proceeded, but remained relatively low in the outer mesocarp. T2 relaxation times for inner and middle mesocarp regions fell during ripening. The data suggest t

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BRUN, TODD A., and HSI-SHENG GOAN. "REALISTIC SIMULATIONS OF SINGLE-SPIN MEASUREMENT VIA MAGNETIC RESONANCE FORCE MICROSCOPY." International Journal of Quantum Information 03, supp01 (2005): 1–9. http://dx.doi.org/10.1142/s0219749905001201.

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The problem of measuring single electron or nuclear spins is of great interest for a variety of purposes, from imaging the structure of molecules to quantum information processing. One of the most promising techniques is magnetic resonance force microscopy (MRFM), in which the force between a spin and a small permanent magnet resonantly drives the oscillations of a microcantilever. Numerous issues arise in understanding this system: thermal noise in the cantilever, shot-noise and back-action from monitoring the cantilever's motion, spin relaxation, and interaction with higher cantilever modes.

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Kjær, L., C. Thomsen, and O. Henriksen. "Evaluation of Biexponential Relaxation Behaviour in the Human Brain by Magnetic Resonance Imaging." Acta Radiologica 30, no. 4 (1989): 433–37. http://dx.doi.org/10.1177/028418518903000420.

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Quantitative estimation of individual biologic components in relaxation curves obtained in vivo may increase the specificity of tissue characterization by magnetic resonance imaging. In this study, the potential of biexponential curve analysis was evaluated in T1 and T2 measurements on the human brain at 1.5 tesla. Optimal experimental conditions were carefully observed, including the use of long TR values and a very small voxel size. T1 determination was based on a 12-points partial saturation inversion recovery pulse sequence. T2 determination involved a multiple spin echo sequence with 32 e

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Zhang, Yapeng, Jingjing Cheng, and Wenzhong Liu. "Characterization and Relaxation Properties of a Series of Monodispersed Magnetic Nanoparticles." Sensors 19, no. 15 (2019): 3396. http://dx.doi.org/10.3390/s19153396.

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Magnetic iron oxide nanoparticles are relatively advanced nanomaterials, and are widely used in biology, physics and medicine, especially as contrast agents for magnetic resonance imaging. Characterization of the properties of magnetic nanoparticles plays an important role in the application of magnetic particles. As a contrast agent, the relaxation rate directly affects image enhancement. We characterized a series of monodispersed magnetic nanoparticles using different methods and measured their relaxation rates using a 0.47 T low-field Nuclear Magnetic Resonance instrument. Generally speakin

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Kondo, Yasushi, and Masayuki Matsuzaki. "Study of open systems with molecules in isotropic liquids." Modern Physics Letters B 32, no. 15 (2018): 1830002. http://dx.doi.org/10.1142/s0217984918300028.

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We are interested in dynamics of a system in an environment, or an open system. Such phenomena as crossover from Markovian to non-Markovian relaxation and thermal equilibration are of our interest. Open systems have experimentally been studied with ultra cold atoms, ions in traps, optics, and cold electric circuits because well-isolated systems can be prepared here and thus the effects of environments can be controlled. We point out that some molecules solved in isotropic liquid are well isolated and thus they can also be employed for studying open systems in Nuclear Magnetic Resonance (NMR) e

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Reynhardt, E. C. "A nuclear magnetic resonance study of 1H, 23Na, and 31P relaxation and molecular dynamics in the sodium salts of some pyrophosphates." Canadian Journal of Physics 67, no. 6 (1989): 592–98. http://dx.doi.org/10.1139/p89-108.

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Proton second moments and spin-lattice relaxation times in the laboratory and rotating frames and 31P and 23Na spin-lattice relaxation times in the laboratory frame have been measured over the temperature region 295 > T > 100 K for the sodium pyrophosphate salts, Na2P2O7∙10H2O and Na2H2P2O7. Laboratory-frame 31P and 23Na spin-lattice relaxation times have also been measured over the same temperature range for Na4P2O7. In the case of Na4P2O7∙10H2O, the results show clearly that the H2O molecules execute a twofold jump motion at higher temperatures. The potential barriers to these motions

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Brox, Timothy I., Mark L. Skidmore, and Jennifer R. Brown. "Characterizing the internal structure of laboratory ice samples with nuclear magnetic resonance." Journal of Glaciology 61, no. 225 (2015): 55–64. http://dx.doi.org/10.3189/2015jog14j133.

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AbstractDue to solute impurities and freezing-point depression in polycrystalline ice, a complicated and dynamic network of liquid water forms within the solid ice matrix at the boundaries between ice crystal grains. Impurity concentrations, temperature and pressure influence this network structure and impact physical, transport and rheological properties of ice. However, the nature of this internal network structure is not fully understood. Here we utilize nuclear magnetic resonance (NMR) measurements of diffusion and magnetic relaxation to study the geometry and interconnectivity of the liqu

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Mietchen, D., M. Aberhan, B. Manz, et al. "Three-dimensional Magnetic Resonance Imaging of fossils across taxa." Biogeosciences 5, no. 1 (2008): 25–41. http://dx.doi.org/10.5194/bg-5-25-2008.

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Abstract. The frequency of life forms in the fossil record is largely determined by the extent to which they were mineralised at the time of their death. In addition to mineral structures, many fossils nonetheless contain detectable amounts of residual water or organic molecules, the analysis of which has become an integral part of current palaeontological research. The methods available for this sort of investigations, though, typically require dissolution or ionisation of the fossil sample or parts thereof, which is an issue with rare taxa and outstanding materials like pathological or type

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