Anomalous metamagnetic-like transition in a FeRh/Fe3_3Pt interface occurring at T120 K in the field-cooled-cooling curves for low magnetic fields

We report on the magnetic properties of a special configuration of a FeRh thin film. An anomalous behavior on the magnetisation vs. temperature was observed when low magnetic fields are applied in the plane of a thin layer of FeRh deposited on ordered Fe$_3$Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetisation curve at temperatures near 120 K in samples without any heat treatment.Comment: 7 pages, 5 figures. arXiv admin note: text overlap with arXiv:1008.195

Plaquette operators used in the rigorous study of ground-states of the Periodic Anderson Model in D=2D = 2 dimensions

The derivation procedure of exact ground-states for the periodic Anderson model (PAM) in restricted regions of the parameter space and D=2 dimensions using plaquette operators is presented in detail. Using this procedure, we are reporting for the first time exact ground-states for PAM in 2D and finite value of the interaction, whose presence do not require the next to nearest neighbor extension terms in the Hamiltonian. In order to do this, a completely new type of plaquette operator is introduced for PAM, based on which a new localized phase is deduced whose physical properties are analyzed in detail. The obtained results provide exact theoretical data which can be used for the understanding of system properties leading to metal-insulator transitions, strongly debated in recent publications in the frame of PAM. In the described case, the lost of the localization character is connected to the break-down of the long-range density-density correlations rather than Kondo physics.Comment: 34 pages, 5 figure

Screening of Fabry Disease of patients in renal replacement therapy in a population from Lazio (Italy)

Objective: Fabry's disease (FD) is a genetic disorder of lysosomal storage characterized by the intralysosomal accumulation of globotriaosylceramide (Gb3). This genetic mutation causes a total or partial deficit of the α-galactosidase (GAL) enzyme activity. FD has an incidence of 1:40000-60000 born alive. Its prevalence is higher in specific pathological conditions like chronic kidney disease (CKD). The aim of this study was to evaluate the FD prevalence in Italian renal replacement therapy (RRT) patients from Lazio region. Patients and methods: 485 patients in RRT (hemodialysis, peritoneal dialysis, and kidney transplantation) were recruited. The screening test was performed on venous blood sample. The latter was analyzed using specific FD diagnostic kit, based on the analysis of dried blood spots on filter paper. Results: We found 3 cases of positivity to FD (1 female and 2 males). In addition, 1 male patient was identified with biochemical alteration indicative of GAL enzyme deficiency with a genetic variant of the GLA gene of unknown clinical significance. The FD prevalence in our population was 0.60% (1 case out 163), it rises to 0.80% (1 case out of 122) if the genetic variant of unknown clinical significance is considered. Comparing the three subpopulations, we observed a statistically significant difference in GAL activity in transplanted patients compared to dialysis patients (p<0.001). Conclusions: Considering the presence of an enzyme replacement therapy able to modify FD clinical history, it is essential to try to implement FD early diagnoses. However, the screening is too expensive to be extended on large scale, due to the low prevalence of the pathology. The screening should be performed on high-risk populations

Sleep deprivation and Modafinil affect cortical sources of resting state electroencephalographic rhythms in healthy young adults

Objective: It has been reported that sleep deprivation affects the neurophysiological mechanisms underpinning the vigilance. Here, we tested the following hypotheses in the PharmaCog project (www.pharmacog.org): (i) sleep deprivation may alter posterior cortical delta and alpha sources of resting state eyes-closed electroencephalographic (rsEEG) rhythms in healthy young adults; (ii) after the sleep deprivation, a vigilance enhancer may recover those rsEEG source markers. Methods: rsEEG data were recorded in 36 healthy young adults before (Pre-sleep deprivation) and after (Post-sleep deprivation) one night of sleep deprivation. In the Post-sleep deprivation, these data were collected after a single dose of PLACEBO or MODAFINIL. rsEEG cortical sources were estimated by eLORETA freeware. Results: In the PLACEBO condition, the sleep deprivation induced an increase and a decrease in posterior delta (2–4 Hz) and alpha (8–13 Hz) source activities, respectively. In the MODAFINIL condition, the vigilance enhancer partially recovered those source activities. Conclusions: The present results suggest that posterior delta and alpha source activities may be both related to the regulation of human brain arousal and vigilance in quiet wakefulness. Significance: Future research in healthy young adults may use this methodology to preselect new symptomatic drug candidates designed to normalize brain arousal and vigilance in seniors with dementia