Superconducting nanowire quantum interference device based on Nb ultrathin films deposited on self-assembled porous Si templates

Magnetoresistance oscillations were observed on networks of superconducting ultrathin Nb nanowires presenting evidences of either thermal or quantum activated phase slips. The magnetic transport data, discussed in the framework of different scenarios, reveal that the system behaves coherently in the temperature range where the contribution of the fluctuations is important.Comment: accepted for publication on Nanotechnolog

Nonlinear current-voltage characteristics due to quantum tunneling of phase slips in superconducting Nb nanowire networks

We report on the transport properties of an array of N about 30 interconnected Nb nanowires, grown by sputtering on robust porous Si substrates. The analyzed system exhibits a broad resistive transition in zero magnetic field, H, and highly nonlinear V(I) characteristics as a function of H which can be both consistently described by quantum tunneling of phase slips.Comment: accepted for publication on Appl. Phys. Let

Quantum phase slips in superconducting Nb nanowire networks deposited on self-assembled Si templates

Robust porous silicon substrates were employed for generating interconnected networks of superconducting ultrathin Nb nanowires. Scanning electron microscopy analysis was performed to investigate the morphology of the samples, which constitute of polycrystalline single wires with grain size of about 10 nm. The samples exhibit nonzero resistance over a broad temperature range below the critical temperature, fingerprint of phase slippage processes. The transport data are satisfactory reproduced by models describing both thermal and quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires.Comment: accepted for publication on Applied Physics Letter

The endocannabinoid transport inhibitor AM404 differentially modulates recognition memory in rats depending on environmental aversiveness

Cannabinoid compounds may influence both emotional and cognitive processes depending on the level of environmental aversiveness at the time of drug administration. However, the mechanisms responsible for these responses remain to be elucidated. The present experiments investigated the effects induced by the endocannabinoid transport inhibitor AM404 (0.5–5 mg/kg, i.p.) on both emotional and cognitive performances of rats tested in a Spatial Open Field task and subjected to different experimental settings, named High Arousal (HA) and Low Arousal (LA) conditions. The two different experimental conditions influenced emotional reactivity independently of drug administration. Indeed, vehicle-treated rats exposed to the LA condition spent more time in the center of the arena than vehicle-treated rats exposed to the HA context. Conversely, the different arousal conditions did not affect the cognitive performances of vehicle-treated animals such as the capability to discriminate a spatial displacement of the objects or an object substitution. AM404 administration did not alter locomotor activity or emotional behavior of animals exposed to both environmental conditions. Interestingly, AM404 administration influenced the cognitive parameters depending on the level of emotional arousal: it impaired the capability of rats exposed to the HA condition to recognize a novel object while it did not induce any impairing effect in rats exposed to the LA condition. These findings suggest that drugs enhancing endocannabinoid signaling induce different effects on recognition memory performance depending on the level of emotional arousal induced by the environmental conditions

Superconducting properties of Nb thin films deposited on porous silicon templates

Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependence of the superconducting resistive transition width at H=1 Tesla. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.Comment: accepted for publication on Journal of Applied Physic

Communal nesting differentially attenuates the impact of pre-weaning social isolation on behavior in male and female rats during adolescence and adulthood

IntroductionEarly social isolation (ESI) disrupts neurodevelopmental processes, potentially leading to long-lasting emotional and cognitive changes in adulthood. Communal nesting (CN), i.e., the sharing of parental responsibilities between multiple individuals in a nest, creates a socially enriching environment known to impact social and anxiety-related behaviors.MethodsThis study examines the effects of (i) the CN condition and of (ii) ESI during the 3rd week of life (i.e., pre-weaning ESI) on motor, cognitive, and emotional domains during adolescence and adulthood in male and female rats reared in the two different housing conditions, as well as (iii) the potential of CN to mitigate the impact of ESI on offspring.ResultsWe found that in a spontaneous locomotor activity test, females exhibited higher activity levels compared to males. In female groups, adolescents reared in standard housing (SH) condition spent less time in the center of the arena, suggestive of increased anxiety levels, while the CN condition increased the time spent in the center during adolescence, but not adulthood, independently from ESI. The prepulse inhibition (PPI) test showed a reduced PPI in ESI adolescent animals of both sexes and in adult males (but not in adult females), with CN restoring PPI in males, but not in adolescent females. Further, in the marble burying test SH-ESI adolescent males exhibited higher marble burying behavior than all other groups, suggestive of obsessive-compulsive traits. CN completely reversed this stress-induced effect. Interestingly, ESI and CN did not have a significant impact on burying behavior in adult animals of both sexes.DiscussionOverall, our findings (i) assess the effects of ESI on locomotion, sensorimotor gating, and compulsive-like behaviors, (ii) reveal distinct vulnerabilities of males and females within these domains, and (iii) show how early-life social enrichment may successfully counteract some of the behavioral alterations induced by early-life social stress in a sex-dependent manner. This study strengthens the notion that social experiences during early-life can shape emotional and cognitive outcomes in adulthood, and points to the importance of social enrichment interventions for mitigating the negative effects of early social stress on neurodevelopment

Regulation of oxytocin receptor gene expression in obsessive–compulsive disorder: a possible role for the microbiota-host epigenetic axis

Background: Obsessive–compulsive disorder (OCD) is a prevalent and severe clinical condition. Robust evidence suggests a gene-environment interplay in its etiopathogenesis, yet the underlying molecular clues remain only partially understood. In order to further deepen our understanding of OCD, it is essential to ascertain how genes interact with environmental risk factors, a cross-talk that is thought to be mediated by epigenetic mechanisms. The human microbiota may be a key player, because bacterial metabolites can act as epigenetic modulators. We analyzed, in the blood and saliva of OCD subjects and healthy controls, the transcriptional regulation of the oxytocin receptor gene and, in saliva, also the different levels of major phyla. We also investigated the same molecular mechanisms in specific brain regions of socially isolated rats showing stereotyped behaviors reminiscent of OCD as well as short chain fatty acid levels in the feces of rats. Results: Higher levels of oxytocin receptor gene DNA methylation, inversely correlated with gene expression, were observed in the blood as well as saliva of OCD subjects when compared to controls. Moreover, Actinobacteria also resulted higher in OCD and directly correlated with oxytocin receptor gene epigenetic alterations. The same pattern of changes was present in the prefrontal cortex of socially-isolated rats, where also altered levels of fecal butyrate were observed at the beginning of the isolation procedure. Conclusions: This is the first demonstration of an interplay between microbiota modulation and epigenetic regulation of gene expression in OCD, opening new avenues for the understanding of disease trajectories and for the development of new therapeutic strategies

β-Adrenoreceptor Stimulation Mediates Reconsolidation of Social Reward-Related Memories

In recent years, the notion that consolidated memories become transiently unstable after retrieval and require reconsolidation to persist for later use has received strong experimental support. To date, the majority of studies on reconsolidation have focused on memories of negative emotions, while the dynamics of positive memories have been less well studied. Social play, the most characteristic social behavior displayed by young mammals, is important for social and cognitive development. It has strong rewarding properties, illustrated by the fact that it can induce conditioned place preference (CPP). In order to understand the dynamics of positive social memories, we evaluated the effect of propranolol, a β-adrenoreceptor antagonist known to influence a variety of memory processes, on acquisition, consolidation, retrieval and reconsolidation of social play-induced CPP in adolescent rats.Systemic treatment with propranolol, immediately before or after a CPP test (i.e. retrieval session), attenuated CPP 24 h later. Following extinction, CPP could be reinstated in saline--but not in propranolol-treated rats, indicating that propranolol treatment had persistently disrupted the CPP memory trace. Propranolol did not affect social play-induced CPP in the absence of memory retrieval or when administered 1 h or 6 h after retrieval. Furthermore, propranolol did not affect acquisition, consolidation or retrieval of social play-induced CPP.We conclude that β-adrenergic neurotransmission selectively mediates the reconsolidation, but not other processes involved in the storage and stability of social reward-related memories in adolescent rats. These data support the notion that consolidation and reconsolidation of social reward-related memories in adolescent rats rely on distinct neural mechanisms

Легенди та перекази кінця ХVI - початку ХVІІ ст. в записах Петра Могили

For the first time in the history of the Ukrainian folkloristics the author researches the records of legends made by sanctifier Petro Mohyla at the beginning of the 17th century mainly in Kyiv suburbs. The author focuses on authenticity of the texts, their links to the traditional legendry and hagiography as well as methods of recording