Insights into the Effect of Magnetic Confinement on the Performance of Magnetic Nanocomposites in Magnetic Hyperthermia and Magnetic Resonance Imaging.

The combination of superparamagnetic iron oxide nanoparticles (SPIONs) and lipid matrices enables the integration of imaging, drug delivery, and therapy functionalities into smart theranostic nanocomposites. SPION confinement creates new interactions primarily among the embedded SPIONs and then between the nanocomposites and the surroundings. Understanding the parameters that rule these interactions in real interacting (nano)systems still represents a challenge, making it difficult to predict or even explain the final (magnetic) behavior of such systems.

Dynamics of Arabic gum aqueous solutions as revealed by NMR relaxometry.

Background: The purpose of this article is to study molecular dynamics through nuclear magnetic relaxation (NMR) dispersion of Arabic gum aqueous solutions analysed in terms of two-fraction exchange model.

Results: The experiments revealed that relaxation of water molecules was non-monoexponential, which was interpreted in terms of a model describing the magnetization transfer due to exchange of water and polysaccharide protons. The analysis showed that water dynamics decreased slightly with gum content.

Water dynamics in eggs by means of Nuclear Magnetic Resonance relaxometry.

H Nuclear Magnetic Resonance relaxometry has been applied to reveal dynamical properties of water molecules embedded into egg yolk and white of three species: turkey, chicken and quail. Two fractions of water molecules, referred to as confined-water and free-water fractions, have been revealed. It has been demonstrated that translation diffusion of the confined-water fraction is three-dimensional.

Dynamics of Ionic Liquids in Confinement by Means of NMR Relaxometry-EMIM-FSI in a Silica Matrix as an Example.

H and F spin-lattice relaxation studies for 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide in bulk and mesoporous MCM-41 silica matrix confinement were performed under varying temperatures in a broad range of magnetic fields, corresponding to H resonance frequency from 5Hz to 30MHz.A thorough analysis of the relaxation data revealed a three-dimensional translation diffusion of the ions in the bulk liquid and two-dimensional diffusion in the vicinity of the confining walls in the confinement. Parameters describing the translation dynamics were determined and compared.

H spin-lattice NMR relaxation in the presence of residual dipolar interactions - Dipolar relaxation enhancement.

A model of spin-lattice relaxation for spin-1/2 nuclei in the presence of a residual dipole-dipole coupling has been presented. For slow dynamics the model predicts a bi-exponential relaxation at low frequencies, when the residual dipole-dipole interaction dominates the Zeeman coupling. Moreover, according to the model a frequency-specific relaxation enhancement, referred to as Dipolar Relaxation Enhancement (DRE) in analogy to the Quadrupole Relaxation Enhancement (QRE) is expected.

Slow dynamics of solid proteins - Nuclear magnetic resonance relaxometry versus dielectric spectroscopy.

H Nuclear Magnetic Resonance (NMR) relaxometry and Dielectric Spectroscopy (DS) have been exploited to investigate the dynamics of solid proteins. The experiments have been carried out in the frequency range of about 10 kHz-40 MHz for NMR relaxometry and 10Hz-20 MHz for DS. The data sets have been analyzed in terms of theoretical models allowing for a comparison of the correlation times revealed by NMR relaxometry and DS.

Dynamics of Molecular Crystals by Means of (1) H NMR Relaxometry: Dynamical Heterogeneity versus Homogenous Motion.

(1) H NMR relaxometry was used to reveal information on the dynamical properties of the molecular crystal (PyH)5 Bi2 Br11 (PyH=C5 H6 N, pyridinium cation), chosen as an example of a solid that exhibits a complex structure and rotational-like dynamics. Experimental studies were performed over a very broad frequency range, from 4 kHz to 40 MHz (referring to the (1) H resonance frequency) versus temperature. The extensive set of data was thoroughly analyzed in terms of two motional models differing with respect to the assumed mechanism (heterogeneous versus homogenous) of the motion of the PyH cations.

Non-cooperative immobilization of residual water bound in lyophilized photosynthetic lamellae.

This study applied 1H-NMR in time and in frequency domain measurements to monitor the changes that occur in bound water dynamics at decreased temperature and with increased hydration level in lyophilizates of native wheat photosynthetic lamellae and in photosynthetic lamellae reconstituted from lyophilizate. Proton relaxometry (measured as free induction decay = FID) distinguishes a Gaussian component S within the NMR signal (o). This comes from protons of the solid matrix of the lamellae and consists of (i) an exponentially decaying contribution L1 from mobile membrane protons, presumably from lipids, and from water that is tightly bound to the membrane surface and thus restricted in mobility; and (ii) an exponentially decaying component L2 from more mobile, loosely bound water pool.

Vibrations and reorientations of H2O molecules in [Sr(H2O)6]Cl2 studied by Raman light scattering, incoherent inelastic neutron scattering and proton magnetic resonance.

Vibrational-reorientational dynamics of H2O ligands in the high- and low-temperature phases of [Sr(H2O)6]Cl2 was investigated by Raman Spectroscopy (RS), proton magnetic resonance ((1)H NMR), quasielastic and inelastic incoherent Neutron Scattering (QENS and IINS) methods. Neutron powder diffraction (NPD) measurements, performed simultaneously with QENS, did not indicated a change of the crystal structure at the phase transition (detected earlier by differential scanning calorimetry (DSC) at TC(h)=252.9 K (on heating) and at TC(c)=226.