1,015 research outputs found

    Microscopic dynamics and relaxation processes in liquid Hydrogen Fluoride

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    Inelastic x-ray scattering and Brillouin light scattering measurements of the dynamic structure factor of liquid hydrogen fluoride have been performed in the temperature rangeT=214÷283K T=214\div 283 K. The data, analysed using a viscoelastic model with a two timescale memory function, show a positive dispersion of the sound velocity c(Q)c(Q) between the low frequency value c0(Q)c_0(Q) and the high frequency value c∞α(Q)c_{\infty \alpha}(Q). This finding confirms the existence of a structural (α\alpha) relaxation directly related to the dynamical organization of the hydrogen bonds network of the system. The activation energy EaE_a of the process has been extracted by the analysis of the temperature behavior of the relaxation time τα(T)\tau_\alpha(T) that follows an Arrhenius law. The obtained value for EaE_a, when compared with that observed in another hydrogen bond liquid as water, suggests that the main parameter governing the α\alpha-relaxation process is the number of the hydrogen bonds per molecule.Comment: 9 pages and 12 figure

    Tunneling of polarized fermions in 3D double wells

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    We study the tunneling of a spin polarized Fermi gas in a three-dimensional double well potential, focusing on the time dynamics starting from an initial state in which there is an imbalance in the number of particles in the two wells. Although fermions in different doublets of the double well tunnel with different frequencies, we point out that (incoherent) oscillations of a large number of particles can arise, as a consequence of the presence of transverse degrees of freedom. Estimates of the doublet structure and of the occupation of transverse eigenstates for a realistic experimental setup are provided.Comment: 10 pages, Typos corrected and figures changed - published in Laser Physics, issue on the LPHYS'11 conference (Sarajevo, 2011

    On the origin of the λ\lambda-transition in liquid Sulphur

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    Developing a novel experimental technique, we applied photon correlation spectroscopy using infrared radiation in liquid Sulphur around TλT_\lambda, i.e. in the temperature range where an abrupt increase in viscosity by four orders of magnitude is observed upon heating within few degrees. This allowed us - overcoming photo-induced and absorption effects at visible wavelengths - to reveal a chain relaxation process with characteristic time in the ms range. These results do rehabilitate the validity of the Maxwell relation in Sulphur from an apparent failure, allowing rationalizing the mechanical and thermodynamic behavior of this system within a viscoelastic scenario.Comment: 5 pages, 4 eps figures, accepted in Phys. Rev. Let

    a consensus statement for the clinical use of the renal sodium glucose co transporter 2 inhibitor dapagliflozin in patients with type 2 diabetes mellitus

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    ABSTRACTIntroduction: The present review developed a clinical consensus based on a Delphi method on Dapagliflozin, a selective inhibitor of the renal sodium-glucose co-transporter-2 (SGLT2-I) in the treatment of patients with Type 2 diabetes mellitus.Areas covered: Panel members, using a 5-point scale, were asked to rate 9 statements on pharmakodinamic, mode of action on glycaemic and extra-glycaemic effects, and safety of dapaglifozin, Members also aimed to identify the patient most susceptible to the treatment with dapagliflozin .Expert commentary: Dapagliflozin is effective in lowering the plasma glucose concentration with a good safety profile. Dapagliflozin can be utilized in combination with all other antihyperglycaemic agents at all stages of the disease: however, a reduced GFR limits its efficacy. As for the other drugs of the class, Dapagliflozin positively modifies other risk factors for CV disease: these effects will be tested in the so far largest cardiovascular outcome trial for the SGLT2 inh..

    Natural history and risk factors for diabetic kidney disease in patients with T2D: lessons from the AMD-annals

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    The Associazione Medici Diabetologi (AMD) annals initiative is an ongoing observational survey promoted by AMD. It is based on a public network of about 700 Italian diabetes clinics, run by specialists who provide diagnostic confirmation and prevention and treatment of diabetes and its complications. Over the last few years, analysis of the AMD annals dataset has contributed several important insights on the clinical features of type-2 diabetes kidney disease and their prognostic and therapeutic implications. First, non-albuminuric renal impairment is the predominant clinical phenotype. Even though associated to a lower risk of progression compared to overt albuminuria, it contributes significantly to the burden of end-stage renal disease morbidity. Second, optimal blood pressure control provides significant but incomplete renal protection. It reduces albuminuria but there may be a J curve phenomenon with eGFR at very low blood pressure values. Third, hyperuricemia and diabetic hyperlipidemia, namely elevated triglycerides and low HDL cholesterol, are strong independent predictors of chronic kidney disease (CKD) onset in diabetes, although the pathogenetic mechanisms underlying these associations remain uncertain. Fourth, the long-term intra-individual variability in HbA1c, lipid parameters, uric acid and blood pressure plays a greater role in the appearance and progression of CKD than the absolute value of each single variable. These data help clarify the natural history of CKD in patients with type 2 diabetes and provide important clues for designing future interventional studies

    Immunolocalization of Nesfatin-1 in the Gastrointestinal Tract of the Common Bottlenose Dolphin Tursiops truncatus

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    SIMPLE SUMMARY: Nesfatin-1 (Nesf-1) is a neuropeptide that plays important roles in regulating food intake, mainly related to its anorexigenic effect, and it is mainly distributed in the digestive systems of all vertebrates. With this study, we expand knowledge on the localization of Nesf-1 in the digestive tract of an aquatic mammalian species, the common bottlenose dolphin (Tursiops truncatus), allowing comparative study on terrestrial mammals. Dolphin tissue samples (three gastric chambers and intestine) were provided by the Mediterranean Marine Mammal Tissue Bank of the Department of Comparative Biomedicine and Food Science of the University of Padova (Italy). ABSTRACT: First identified as an anorexigenic peptide, in the last decades, several studies have suggested that Nesfatin-1 (Nesf-1) is a pleiotropic hormone implicated in numerous regulatory processes in peripheral organs and tissues. In vertebrates, Nesf-1 is indeed expressed in the central nervous system and peripheral organs. In this study, we characterized the pattern of Nesf-1 distribution within the digestive tract of the common bottlenose dolphin (Tursiops truncatus), composed of three gastric chambers and an intestine without a clear subdivision in the small and large intestine, also lacking a caecum. Our results indicated that Nesf-1 is widely distributed in cells of the mucosal epithelium of the gastric chambers. Most of the immunoreactivity was observed in the second chamber, compared to the first and third chambers. Immunopositivity was also found in nerve fibers and neurons, scattered or/and clustered in ganglion structures along all the examined gastrointestinal tracts. These observations add new data on the highly conserved role of Nesf-1 in the mammalian digestive system

    Quantum Quenches in Integrable Field Theories

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    We study the non equilibrium time evolution of an integrable field theory in 1+1 dimensions after a sudden variation of a global parameter of the Hamiltonian. For a class of quenches defined in the text, we compute the long times limit of the one point function of a local operator as a series of form factors. Even if some subtleties force us to handle this result with care, there is a strong evidence that for long times the expectation value of any local operator can be described by a generalized Gibbs ensemble with a different effective temperature for each eigenmode

    Efficacy and safety of dapagliflozin in patients with type 2 diabetes and moderate renal impairment (chronic kidney disease stage 3A): The DERIVE Study

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    Aims: Dapagliflozin is a selective inhibitor of sodium glucose co-transporter 2 (SGLT2). This study assessed the efficacy and safety of dapagliflozin 10 mg vs placebo in patients with type 2 diabetes (T2D) and moderate renal impairment (estimated glomerular filtration rate [eGFR], 45-59mL/min/1.73m2; chronic kidney disease [CKD] stage 3A). Materials and methods: In this double-blind, parallel group, Phase 3 study (NCT02413398, clinicaltrials.gov) patients with inadequately controlled T2D (HbA1c 7.0%-11.0%) were randomized (1:1) to dapagliflozin 10 mg once daily (N=160) or matching placebo (N=161) for 24weeks. Randomization was stratified by pre-enrolment glucose-lowering therapy. The primary endpoint was change from baseline in HbA1c at Week 24. Results: At Week 24, compared with placebo, dapagliflozin significantly decreased HbA1c (difference [95% CI], -0.34% [-0.53, -0.15]; P < 0.001), body weight (difference [95% CI], -1.25kg [-1.90, -0.59]; P < 0.001), fasting plasma glucose (difference [95% CI], -0.9 mmol/L [-1.5, -0.4]; P = 0.001) and systolic blood pressure (difference [95% CI], -3.1 mmHg [-6.3, 0.0]; P < 0.05). Decreases from baseline in eGFR were greater with dapagliflozin than placebo at Week 24 (-2.49mL/min/1.73m2[-4.96, -0.02]), however, eGFR returned to baseline levels at Week 27 (3 weeks post-treatment) (0.61mL/min/1.73m2[-1.59, 2.81]). No increase in adverse events (AEs; 41.9% vs 47.8%) or serious AEs (5.6% vs 8.7%) were reported with dapagliflozin versus placebo. No AEs of bone fractures, amputations or DKA were reported. Conclusions: The findings of this study (NCT02413398, clinicaltrials.gov) support the positive benefit/risk profile of dapagliflozin for the treatment of patients with T2D and CKD 3A

    Quantum quench dynamics of the sine-Gordon model in some solvable limits

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    In connection with the the thermalization problem in isolated quantum systems, we investigate the dynamics following a quantum quench of the sine-Gordon model in the Luther-Emery and the semiclassical limits. We consider the quench from the gapped to the gapless phase as well as reversed one. By obtaining analytic expressions for the one and two-point correlation functions of the order parameter operator at zero-temperature, the manifestations of integrability in the absence of thermalization in the sine-Gordon model are studied. It is thus shown that correlations in the long time regime after the quench are well described by a generalized Gibbs ensemble. We also consider the case where the system is initially in contact with a reservoir at finite temperature. The possible relevance of our results to current and future experiments with ultracold atomic systems is also critically considered.Comment: 21 pages, no figures. To appear in New J. Phys

    Exact time evolution of space- and time-dependent correlation functions after an interaction quench in the 1D Bose gas

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    We consider the non-equilibrium dynamics of the interacting Lieb-Liniger gas after instantaneously switching the interactions off. The subsequent time evolution of the space- and time-dependent correlation functions is computed exactly. Different relaxation behavior is observed for different correlation functions. The long time average is compared with the predictions of several statistical ensembles. The generalized Gibbs ensemble restricted to a fixed number of particles is shown to give correct results at large times for all length scales.Comment: 9 pages, 11 figure
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