Relaxation Dynamics and Phase Transitions in Ionic Liquids: Viscoelastic Properties from the Liquid to the Solid State.

In the present work we performed low-frequency mechanical spectroscopy experiments to measure the mechanical modulus of two ionic liquids and its variation during the main phase transitions occurring by varying the temperature, in the both liquid and the solid states. The liquids share the same anion, the bis(trifluoromethanesulfonyl)imide, and present different cations, 1-butyl-1-methylpyrrolidinium and 1-allyl-3-H-imidazolium. A thermally activated relaxation process is found in the liquid phase and is analyzed in terms of a modified Debye model. The obtained parameters provide indications about the nature and the mechanism giving rise to the peak, which is attributed to the ions motion by means of hopping processes. Moreover, density functional calculations were performed, and the comparison with the analysis of the experimental data suggests that the anion conformers are likely to be involved in the different configurations among which the ions can rearrange.

Interaction of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide with an electrospun PVdF membrane: Temperature dependence of the concentration of the anion conformers.

We measured the temperature dependence of the infrared absorption spectrum of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PY R14-TFSI) between 160 and 330 K, through all the phase transitions presented by this compound. The comparison of the experimental spectra with the calculated vibration modes of different conformers of the ions composing the ionic liquid allowed to detect the presence of both conformers of TFSI in the liquid, supercooled, and glass phases, while only the trans-conformer is retained in both solid phases. When the ionic liquid swells a polyvinylidenefluoride (PVdF) electrospun membrane, the cis-rotamer is detected in all phases, since the interaction between the polymer and the ionic liquid inhibits the complete transformation of TFSI into the trans-conformer in the solid phases. Computational results confirm that in the presence of a PVdF chain, cis-TFSI becomes the lowest energy conformer. Therefore, the interaction with the polymer alters the physical properties of the ionic liquid.

Stabilization of different conformers of bis(trifluoromethanesulfonyl)imide anion in ammonium-based ionic liquids at low temperatures.

The infrared absorption spectra of two ionic liquids with bis(trifluoromethanesulfonyl)imide (TFSI) as an anion and ammonium with different alkyl chains as cations are reported as a function of temperature. Using the comparison with ab initio calculations of the infrared-active intramolecular vibrations, the experimental lines were ascribed to the various ions composing the ionic liquids. In the liquid state of the samples, both conformers of the TFSI ion are present. In the solid state, however, the two conformers survive in N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI), while only cis-TFSI is retained in N-trimethyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide (TMHA-TFSI). We suggest that the longer alkyl chains of the former compound stabilize the less stable conformer of TFSI by means of stronger interactions between anions and cations.

[The isolated thyroid nodule: notes on our personal experience]. / Il nodo tiroideo isolato: appunti sulla nostra esperienza.

An analysis of 255 patients operated for isolated thyroid nodes is made. Of these, 81% were cold nodes and 19% hot. Carcinomas were present in 21 cases. One carcinoma appeared as a scintigraphically hot node. The frequency of carcinomas, in relation to the nodules observed, was roughly the same in the two sexes. There is parallelism in behaviour of the rate in the two sexes as regards cold nodes, while this is not true for hot nodes. The importance of some recent diagnostic techniques is briefly discussed.

[Behavior of calcemia in breast malignancy. Note I (author's transl)]. / Sul comportamento della calcemia nelle neoplasie della mammella. (Nota 1).

The authors report a statistical investigation conducted in 95 patients with mammary carcinoma, designed to show the behavior of calcemia in the course of this malignancy. The data were analyzed statistically by the binomial test, the scatter of values (F test of Snedecor), and the t test of Student. The authors confirmed the existence of a statistically significant alteration of calcemia only in the group of patients with metastasis to bone versus control subjects; conversely there was no significant difference of distribution in the various groups in regard to values beyond those given as normal.

[Incidence of recurrent nerve paralysis in personal cases of thyroid surgery]. / Incidenza della paralisi ricorrenziale nella nostra casistica di chirurgia tiroidea.

The authors review their series of thyroid operations, totaling 383 cases in the last seven years. In that series the incidence of recurrent nerve lesions leading to permanent sequels was 1.07% (all treated without surgical preparation of the nerve); an additional 0.53% of the patients developed transient paralysis of the recurrent nerve--of which the authors discuss the possible etiology. The authors conclude by stating the need for careful recognition of the recurrent nerve in all surgical procedures involving the thyroid gland, except some enucleo-resections; they confirm the importance of branches of the inferior thyroid artery and the inferior horn of the thyroid cartilage as reference points.