RESUMO
Recent hydrides-driven advent in the high-pressure phonon-mediated superconductivity motivates research on chemical elements which compound with hydrogen. It is desired that such elements should allow chemical pre-compression of hydrogen to assure the induction of the superconducting phase with the high transition temperature (T C). Herein, we present detailed theoretical insight into the properties of the superconducting state induced under pressure (p) in two of such component elements, namely selenium (Se) and tellurium (Te) at [Formula: see text] GPa and [Formula: see text] GPa, respectively. The assumed external pressure conditions allow us to conduct our analysis just above previously theoretically predicted bcc-fcc structural phase transition of Se and Te, and identify the possible associated discontinuity effect of the critical temperature. In particular, our numerical analysis is conducted within Migdal-Eliashberg formalism, due to the confirmed electron-phonon pairing mechanism and relatively high electron-phonon coupling constant in the materials of interest. We predict that T C values in Se and Te equal 8.13 K and 5.96 K, respectively, and mark the highest critical temperature values for these elements within the postulated fcc phase. Additionally, we supplement these results by the estimated maximum values of the superconducting energy band gap and the effective mass of electrons. We predict that all these parameters can be used as a guidelines for experimental observation of the critical temperature discontinuity and the corresponding bcc-fcc phase transition in Se and Te superconductors. Moreover, we show that the thermodynamics of superconducting phase in both elements may exhibit deviations from the conventional estimates of the Bardeen-Cooper-Schrieffer theory, and suggest existence of the strong-coupling and retardation effects. Finally, we note that our results can be also instructive for future screening of chemical elements for applications in superconducting hydrides.
RESUMO
The aim of this study was to investigate the potential beneficial effects of dietary anserine and carnosine (CRC) supplementation on cognitive functioning and physical activity of the elderly. The fifty-six subjects (65+) were allocated to the CRC group or placebo group at a 1:1 ratio. The double-blind procedure was used. Data were collected at the baseline and after 13-weeks of supplementation. In the follow up procedure fifty one subjects took part. Chicken meat extract (CME) containing 40% of CRC components (2:1 ratio of anserine to carnosine) was administered 2.5 g per day which allowed to rich the level of 1g CRC in dipeptides supplement. The cognitive function, physical capacity, body measurements, blood pressure and heart rate (HR) were assessed. After supplementation Body Mass Index (BMI) decreased significantly (p<0.05) in the CRC group performance comparing the placebo group. In two of six Senior Fitness Test the scores increased significantly (p<0.05) in CRC group comparing to the placebo group. The perceived exertion differed significantly (p<0.05) at the baseline and after follow up at the CRC group. The mean values of the Short Test of Mental Status (STMS) scores showed the significant (p<0.04) increase only in CRC group, in the subscores of construction/copying, abstraction and recall. Conducted anserine and carnosine supplementation in the elderly brings promising effects on cognitive functioning and physical capacity of participants. However, further studies are needed.