Structural Anomaly in Glasses: Molecular Dynamics Study of Organic Radical in Dibutylphthalate at Different Temperatures.

Understanding the heterogeneous nano/microscopic structures of various organic glasses is fundamental and necessary for many applications. Recently, unusual structural phenomena have been observed experimentally in various organic glasses near their glass transition temperatures (Tg), including dibutyl phthalate (DBP). In particular, the librational motion of radical probe in the glass is progressively suppressed upon temperature increase.

Phosphine oxides as NMR and IR spectroscopic probes for the estimation of the geometry and energy of PO⋯H-A hydrogen bonds.

In this work we evaluate the possibility of using the NMR and IR spectral properties of the PO group to estimate the geometry and strength of hydrogen bonds which it forms with OH-, NH- and CH-acids. The results of the DFT study of 70 hydrogen-bonded 1 : 1 complexes of a model trimethylphosphine oxide, MePO, with various proton donors in the gas phase and in aprotic medium (modelled as a polarizable continuum) are presented. Four types of hydrogen bonds with the general formula MePO⋯H-A were considered, where the A atom is O, C, and N (neutral or cationic acids).

[Guillain-Barre syndrome with cranial nerve damage as complication of COVID-19].

The article presents a clinical example of Guillain-Barre syndrome with a predominant involvement of cranial nerves, which developed after COVID-19. Comprehensive clinical and laboratory diagnostics, including examination of cerebrospinal fluid, electromyography, examination for possible etiological infectious agents, was carried out. A course of pathogenetic therapy was used in the form of plasmapheresis sessions, supportive therapy.

Inherent heterogeneities and nanostructural anomalies in organic glasses revealed by EPR.

Intriguing heterogeneities and nanostructural reorganizations of glassy ionic liquids (ILs) have recently been found using electron paramagnetic resonance (EPR) spectroscopy. Alkyl chains of IL cations play the key role in such phenomena and govern the anomalous temperature dependence of local density and molecular mobility. In this paper we evidence and study similar manifestations in a variety of common non-IL glasses, which also contain molecules with alkyl chains.

Mixed-Valence Compounds as Polarizing Agents for Overhauser Dynamic Nuclear Polarization in Solids*.

Herein, we investigate a novel set of polarizing agents-mixed-valence compounds-by theoretical and experimental methods and demonstrate their performance in high-field dynamic nuclear polarization (DNP) NMR experiments in the solid state. Mixed-valence compounds constitute a group of molecules in which molecular mobility persists even in solids. Consequently, such polarizing agents can be used to perform Overhauser-DNP experiments in the solid state, with favorable conditions for dynamic nuclear polarization formation at ultra-high magnetic fields.