Biomedical subjects

A Cervellino

Publications and source records attributed to A Cervellino.

4 recordsLinked to original sources

PubMed2006

Effect of cabergoline added to levodopa treatment on sleep-wake cycle in idiopathic Parkinson's disease: an open label 24-hour polysomnographic study.

Few studies focused on the effects of cabergoline on sleep-wake cycle in PD. Twelve patients affected by PD treated with levodopa as monotherapy underwent two 24-hour ambulatory polysomnographic (A-PSG) sessions twice: in baseline condition (levodopa as monotherapy) and after addition of cabergoline. In each condition, a subjective evaluation of sleep quality and daytime sleepiness was obtained by means of Parkinson's disease Sleep Scale (PDSS) and the Epworth Sleepiness Scale. The statistical analysis of sleep parameters revealed a significant increase of sleep efficiency and slow wave sleep under cabergoline. The PDSS total score showed a significant improvement of overall sleep quality after cabergoline. No significant changes in daytime sleepiness were observed. No patient referred and/or showed sleep attacks before and after addition of cabergoline. We hypothesize that the long-lasting effect of cabergoline may improve the objective quality of nocturnal sleep in PD patients complaining nocturnal motor disability without inducing daytime sleepiness.

Aged↗

PubMed2006

Spin dynamics and magnetic order in magnetically frustrated Tb2Sn2O7.

We report a study of the geometrically frustrated magnetic material Tb2Sn2O7 by the positive muon-spin relaxation technique. No signature of a static magnetically ordered state is detected while neutron magnetic reflections are observed in agreement with a published report. This is explained by the dynamical nature of the ground state of Tb2Sn2O7: the Tb3+ magnetic moment characteristic fluctuation time is approximately 10(-10) s. The strong effect of the magnetic field on the muon-spin-lattice relaxation rate at low fields indicates a large field-induced increase of the magnetic density of states of the collective excitations at low energy.

Journal Article↗

PubMed2005

The algebraic approach to the phase problem.

A rather detailed report is presented on the present status of the algebraic approach to the phase problem in the case of an ideal crystal in order to make clear that some points must still be proven for it to apply to neutron scattering. To make this extension, the most important results that were previously obtained in the case of X-ray scattering are derived again by a different procedure. By so doing, the three-dimensional case is treated explicitly, the polynomial equations in a single variable whose roots determine the positions of the scattering centres are explicitly reported and the procedure is shown to generalize to neutron scattering, overcoming the difficulty related to the non-positivity of the scattering density. In this way, it is fully proven that the atomicity assumption removes the phase ambiguity in the sense that the full diffraction pattern of an ideal crystal can uniquely be reconstructed from a suitable finite portion of it in both X-ray and neutron scattering. The procedures able to isolate these portions that contain the pattern's full information are also given.

Algorithms↗

PubMed2001

Quasiperiodicity in decagonal phases forced by inclined net planes?

It is generally assumed that decagonal quasicrystals show periodically arranged atomic layers only on net planes perpendicular to the tenfold axis and quasiperiodically arranged ones parallel to it. However, there also do exist only slightly puckered atomic layers that are periodically arranged and inclined to the tenfold axis. They coincide with the net planes of the periodic average structures of the decagonal phase and are related to the strongest Bragg reflections. Since they link quasiperiodic and periodic directions, inclined net planes may play a crucial role for growth and stabilization of decagonal quasicrystals. In fact, it is shown how ideal quasiperiodic long-range order and inflation symmetry allow for the existence of inclined net planes with small corrugation and reinforce the relation with the periodic average structures.

Journal Article↗