131 research outputs found
Geometric phases in superconducting qubits beyond the two-level-approximation
Geometric phases, which accompany the evolution of a quantum system and
depend only on its trajectory in state space, are commonly studied in two-level
systems. Here, however, we study the adiabatic geometric phase in a weakly
anharmonic and strongly driven multi-level system, realised as a
superconducting transmon-type circuit. We measure the contribution of the
second excited state to the two-level geometric phase and find good agreement
with theory treating higher energy levels perturbatively. By changing the
evolution time, we confirm the independence of the geometric phase of time and
explore the validity of the adiabatic approximation at the transition to the
non-adiabatic regime.Comment: 5 pages, 3 figure
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
Electron tunneling into a quantum wire in the Fabry-Perot regime
We study a gated quantum wire contacted to source and drain electrodes in the
Fabry-Perot regime. The wire is also coupled to a third terminal (tip), and we
allow for an asymmetry of the tip tunneling amplitudes of right and left moving
electrons. We analyze configurations where the tip acts as an electron injector
or as a voltage-probe, and show that the transport properties of this
three-terminal set-up exhibit very rich physical behavior. For a
non-interacting wire we find that a tip in the voltage-probe configuration
affects the source-drain transport in different ways, namely by suppressing the
conductance, by modulating the Fabry-Perot oscillations, and by reducing their
visibility. The combined effect of electron electron interaction and finite
length of the wire, accounted for by the inhomogeneous Luttinger liquid model,
leads to significantly modified predictions as compared to models based on
infinite wires. We show that when the tip injects electrons asymmetrically the
charge fractionalization induced by interaction cannot be inferred from the
asymmetry of the currents flowing in source and drain. Nevertheless interaction
effects are visible as oscillations in the non-linear tip-source and tip-drain
conductances. Important differences with respect to a two-terminal set-up
emerge, suggesting new strategies for the experimental investigation of
Luttinger liquid behavior.Comment: 27 pages, 10 figure
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 arrestâspecific 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
Real Time Marine Data Acquisition: The Coastal Oceanographic Observatory Network in the Adriatic sea.
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Influence of a highâimpact multidimensional rehabilitation program on the gut microbiota of patients with multiple sclerosis
Multiple sclerosis (MS) is a neurodegenerative inflammatory condition mediated by autoreactive immune processes. Due to its potential to influence host immunity and gutâbrain communication, the gut microbiota has been suggested to be involved in the onset and progression of MS. To date, there is no definitive cure for MS, and rehabilitation programs are of the utmost importance, especially in the later stages. However, only a few people generally participate due to poor support, knowledge, and motivation, and no information is available on gut microbiota changes. Herein we evaluated the potential of a brief highâimpact multidimensional rehabilitation program (BâHIPE) in a leisure environment to affect the gut microbiota, mitigate MS symptoms and improve quality of life. BâHIPE resulted in modulation of the MSâtypical dysbiosis, with reduced levels of pathobionts and the replenishment of beneficial shortâchain fatty acid producers. This partial recovery of a eubiotic profile could help counteract the inflammatory tone typically observed in MS, as supported by reduced circulating lipopolysaccharide levels and decreased populations of proâinflammatory lymphocytes. Improved physical performance and fatigue relief were also found. Our findings pave the way for integrating clinical practice with holistic approaches to mitigate MS symptoms and improve patientsâ quality of life
Gene expression profiling in white blood cells reveals new insights into the molecular mechanisms of thalidomide in children with inflammatory bowel disease
Thalidomide has emerged as an effective immunomodulator in the treatment of pediatric patients with inflammatory bowel disease (IBD) refractory to standard therapies. Cereblon (CRBN), a component of E3 protein ligase complex that mediates ubiquitination and proteasomal degradation of target proteins, has been identified as the primary target of thalidomide. CRBN plays a crucial role in thalidomide teratogenicity, however it is unclear whether it is also involved in the therapeutic effects in IBD patients. This study aimed at identifying the molecular mechanisms underpinning thalidomide action in pediatric IBD. In this study, ten IBD pediatric patients responsive to thalidomide were prospectively enrolled. RNA-sequencing (RNA-seq) analysis and functional enrichment analysis were carried out on peripheral blood mononuclear cells (PBMC) obtained before and after twelve weeks of treatment with thalidomide. RNA-seq analysis revealed 378 differentially expressed genes before and after treatment with thalidomide. The most deregulated pathways were cytosolic calcium ion concentration, cAMP-mediated signaling, eicosanoid signaling and inhibition of matrix metalloproteinases. Neuronal signaling mechanisms such as CREB signaling in neurons and axonal guidance signaling also emerged. Connectivity Map analysis revealed that thalidomide gene expression changes were similar to those exposed to MLN4924, an inhibitor of NEDD8 activating enzyme, suggesting that thalidomide exerts its immunomodulatory effects by acting on the ubiquitin-proteasome pathway. In vitro experiments on cell lines confirmed the effect of thalidomide on candidate altered pathways observed in patients. These results represent a unique resource for enhanced understanding of thalidomide mechanism in pediatric patients with IBD, providing novel potential targets associated with drug response
Bridging the gap between chronic cerebrospinal venous insufficiency and Ménière disease
M\ue9ni\ue8re disease (MD) is a chronic illness of the inner ear that affects a substantial number of patients every year worldwide. Because of a dearth of well-controlled studies, the medical and surgical management of MD remains quite empirical. The main reason is that it is very difficult to investigate patients affected with \u201cCertain MD\u201d due to the post-mortem criterion necessary for this diagnostic grade. The aim of this paper is an attempt to approach MD into the context of the more recent findings about the global brain waste clearance system, to which inner ear is anatomically and functionally connected, in order to build a reasonable model of MD pathogenesis. it seems nowadays reasonable to state that CCSVI may be the anatomical background to develop endolymphatic hydrops in MD, the worldwide accepted pathogenetic mechanism of the disease. The mechanism leading from CCSVI to MD is still debated. Since MD has been correlated mostly to a wide and different diseases and treatments, CCSVI may be considered more than a cause of MD per se, rather the anatomical predisposition to develop the disease. CCSVI may lead to endolymphatic hydrops through a pure \u201chydraulic\u201d mechanism but in the model proposed in this paper CCSVI interplays with the Glymphatic (GS) and Brain Lymphatic System (LS) and MD development is due to a failure of the congenital venous abnormalities: MD develops when vascular and/or glymphatic and/or lymphatic compensation fails
Limnological studies on two acid sensitive lakes in the Central Alps (lakes Paione Superiore and Paione Inferiore, Italy)
A limnological study was performed during 1991 and 1992 on lakes Paione Superiore (LPS)and Paione Inferiore (LPI), located in the Ossola Valley, Central Alps. The two lakes are characterized by very low alkalinity values (LPI <3ueq l-1); notwithstanding the relatively low atmospheric acid load, diatom remains, carbonaceous particles and pigment profiles in the sediments all indicate that the two lakes have undergone acidification since the fifties. The biological communities (phyto-zooplankton and macrobenthic fauna) are simplified, in consequence of the extreme physical and chemical conditions. The biological characteristics of the two lakes are discussed in relation to the water chemistry and the presence or absence of stocked fis
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