Detection of Tiny Mechanical Motion by Means of the Ratchet Effect

We propose a position detection scheme for a nanoelectromechanical resonator based on the ratchet effect. This scheme has an advantage of being a dc measurement. We consider a three-junction SQUID where a part of the superconducting loop can perform mechanical motion. The response of the ratchet to a dc current is sensitive to the position of the resonator and the effect can be further enhanced by biasing the SQUID with an ac current. We discuss the feasibility of the proposed scheme in existing experimental setups.Comment: 8 pages, 9 figure

Photon production from the vacuum close to the super-radiant transition: When Casimir meets Kibble-Zurek

The dynamical Casimir effect (DCE) predicts the generation of photons from the vacuum due to the parametric amplification of the quantum fluctuation of an electromagnetic field\cite{casimir1,casimir2}. The verification of such effect is still elusive in optical systems due to the very demanding requirements of its experimental implementation. This typically requires very fast changes of the boundary conditions of the problem, such as the high-frequency driving of the positions of the mirrors of a cavity accommodating the field. Here, we show that an ensemble of two-level atoms collectively coupled to the electromagnetic field of a cavity (thus embodying the quantum Dicke model\cite{dicke}), driven at low frequencies and close to a quantum phase transition, stimulates the production of photons from the vacuum. This paves the way to an effective simulation of the DCE through a mechanism that has recently found an outstanding experimental demonstration\cite{esslinger}. The spectral properties of the emitted radiation reflect the critical nature of the system and allow us to link the detection of DCE to the Kibble-Zurek mechanism for the production of defects when crossing a continuous phase transition\cite{KZ1,KZ2}. We illustrate the features of our proposal by addressing a simple cavity quantum-electrodynamics (cQED) setting of immediate experimental realisation.Comment: 4+1 pages, major changes in the second part of the paper. To appear in Physical Review Letter

Long Term Ecological Research (LTER) in the Marine Coastal Environment: Basic Concepts and Keystones from the Plankton Communities.

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Long non-coding RNA gas5 and intestinal mmp2 and mmp9 expression: A translational study in pediatric patients with IBD

Background: The long non-coding RNA (lncRNA) growth arrest–specific transcript 5 (GAS5) seems to be involved in the regulation of mediators of tissue injury, in particular matrix metalloproteinases (MMPs), implicated in the pathogenesis of inflammatory bowel disease (IBD). We investigated the role of GAS5 in regulating MMP2 and MMP9 expression in pediatric patients with IBD and in vitro. Methods: In total, 25 IBD patients were enrolled: For each patient paired inflamed and non-inflamed biopsies were collected. RNA was extracted and GAS5, MMP2, and MMP9 were quantified by TaqMan assay. The expression of GAS5 and MMPs was also determined in the human monocytic THP1 cells differentiated into macrophages and stimulated with lipopolysaccharide (LPS). The function of GAS5 was assessed by overexpressing the lncRNA and evaluating the MMPs levels. Results: Real-time PCR results demonstrated a downregulation of GAS5 and an upregulation of both MMPs in inflamed tissues. In vitro data confirmed the trend observed in patients for the three genes: The stimulation with LPS promoted a downregulation of GAS5 while an increase of MMPs was observed. Overexpression experiments showed that higher levels of GAS5 lead to a decrease of both enzymes. Conclusion: These results provide new information about the role of GAS5 in IBD: The lncRNA could mediate tissue damage by modulating the expression of MMPs

A Systematic Review of Cerebral Functional Near-Infrared Spectroscopy in Chronic Neurological Diseases—Actual Applications and Future Perspectives

Background: The management of people affected by age-related neurological disorders requires the adoption of targeted and cost-effective interventions to cope with chronicity. Therapy adaptation and rehabilitation represent major targets requiring long-term follow-up of neurodegeneration or, conversely, the promotion of neuroplasticity mechanisms. However, affordable and reliable neurophysiological correlates of cerebral activity to be used throughout treatment stages are often lacking. The aim of this systematic review is to highlight actual applications of functional Near-Infrared Spectroscopy (fNIRS) as a versatile optical neuroimaging technology for investigating cortical hemodynamic activity in the most common chronic neurological conditions. Methods: We reviewed studies investigating fNIRS applications in Parkinson’s Disease (PD), Alzheimer’s Disease (AD) and Mild Cognitive Impairment (MCI) as those focusing on motor and cognitive impairment in ageing and Multiple Sclerosis (MS) as the most common chronic neurological disease in young adults. The literature search was conducted on NCBI PubMed and Web of Science databases by PRISMA guidelines. Results: We identified a total of 63 peer-reviewed articles. The AD spectrum is the most investigated pathology with 40 articles ranging from the traditional monitoring of tissue oxygenation to the analysis of functional resting-state conditions or cognitive functions by means of memory and verbal fluency tasks. Conversely, applications in PD (12 articles) and MS (11 articles) are mainly focused on the characterization of motor functions and their association with dual-task conditions. The most investigated cortical area is the prefrontal cortex, since reported to play an important role in age-related compensatory mechanism and neurofunctional changes associated to these chronic neurological conditions. Interestingly, only 9 articles applied a longitudinal approach. Conclusion: The results indicate that fNIRS is mainly employed for the cross-sectional characterization of the clinical phenotypes of these pathologies, whereas data on its utility for longitudinal monitoring as surrogate biomarkers of disease progression and rehabilitation effects are promising but still lacking

RESTAURI ROMANTICI ALL'OMBRA DEL CAMPANILE

Il saggio ripercorre la storia dei restauro alla basilica di San'Abbondio a Como con una cronologia degli interventi e un'ipotesi sullo stato di consistenza dell'edificio prima dei restaur