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Context. The Metis coronagraph on board Solar Orbiter offers a new view of coronal mass ejections (CMEs), observing them for the first time with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the H I Ly-alpha line at 121.567 nm, the so-called Metis UV channel. Aims. We show the first Metis observations of a CME, obtained on 16 and 17 January 2021. The event was also observed by the EUI/FSI imager on board Solar Orbiter, as well as by other space-based coronagraphs, such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are combined here with Metis data. Methods. Different images are analysed here to reconstruct the 3D orientation of the expanding CME flux rope using the graduated cylindrical shell model. This also allows us to identify the possible location of the source region. Measurements of the CME kinematics allow us to quantify the expected Doppler dimming in the Ly-alpha channel. Results. Observations show that most CME features seen in the visible-light images are also seen in the Ly-alpha images, although some features in the latter channel appear more structured than their visible-light counterparts. We estimated the expansion velocity of this event to be below 140 km s(-1). Hence, these observations can be understood by assuming that Doppler dimming effects do not strongly reduce the Ly-alpha emission from the CME. These velocities are comparable with or smaller than the radial velocities inferred from the same data in a similar coronal structure on the east side of the Sun. Conclusions. The first observations by Metis of a CME demonstrate the capability of the instrument to provide valuable and novel information on the structure and dynamics of these coronal events. Considering also its diagnostics capabilities regarding the conditions of the ambient corona, Metis promises to significantly advance our knowledge of such phenomena.

In this work, we present an investigation of the wind in the solar corona that has been initiated by observations of the resonantly scattered ultraviolet emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscopic observations that were performed during solar activity cycle 23 by simultaneously imaging the polarized visible light and the H I Lyman-alpha corona in order to obtain high spatial and temporal resolution maps of the outward velocity of the continuously expanding solar atmosphere. The Metis observations, taken on May 15, 2020, provide the first H I Lyman-alpha images of the extended corona and the first instantaneous map of the speed of the coronal plasma outflows during the minimum of solar activity and allow us to identify the layer where the slow wind flow is observed. The polarized visible light (580-640 nm) and the ultraviolet H I Ly alpha (121.6 nm) coronal emissions, obtained with the two Metis channels, were combined in order to measure the dimming of the UV emission relative to a static corona. This effect is caused by the outward motion of the coronal plasma along the direction of incidence of the chromospheric photons on the coronal neutral hydrogen. The plasma outflow velocity was then derived as a function of the measured Doppler dimming. The static corona UV emission was simulated on the basis of the plasma electron density inferred from the polarized visible light. This study leads to the identification, in the velocity maps of the solar corona, of the high-density layer about +/- 10 degrees wide, centered on the extension of a quiet equatorial streamer present at the east limb - the coronal origin of the heliospheric current sheet - where the slowest wind flows at about 160 +/- 18 km s(-1) from 4 R-circle dot to 6 R-circle dot. Beyond the boundaries of the high-density layer, the wind velocity rapidly increases, marking the transition between slow and fast wind in the corona.

Diarrhea is one of the most important causes of mortality in the developing world, being responsible for 2.5 million deaths each year. Many of these deaths are caused by enterotoxigenic strains of bacteria, like Escherichia coli, that produce enterotoxins that cause acute watery diarrhea, commonly defined as secretory diarrhea. Studies on symptomatic patients indicate a high prevalence of enterotoxigenic E. coli strains producing the heat-stable toxin, STa. STa is a small, cysteine-rich peptide that binds to the extracellular receptor domain of guanylyl cyclase C (GCC), located at the luminal membrane of intestinal epithelial cells. GCC and its endogenous peptide ligands, guanylin and uroguanylin, play a key role in balancing water absorption and hydration of the intestinal lumen, as exemplified by the finding that loss of GCC function causes severe dehydration of the intestinal lumen, culminating in intestinal obstruction. From a mechanistic viewpoint, reduction of GCC activity offers an efficient approach to limit enterotoxigenic E. coli- provoked secretory diarrhea. Inhibition of GCC-mediated cGMP production would not only reduce anion secretion, but would also restore NHE3 activity, resulting in a comprehensive antidiarrheal action. In the present study, two novel phenylpyrimidinone derivatives were simultaneously synthesized and tested for their ability to block STa-induced CFTR activity in T84 cells.

Introduction: Low-dose acetylsalicylic acid is used as antithrombotic agent and the enteric-coated formulations are widely used to minimize the gastrointestinal side effects. Aim: To compare the bioavailability of two acetylsalicylic acid formulations (Ecasil-81®, 81 mg coated tablet) in fasting healthy volunteers. Methods: Healthy volunteers (n=16) were recruited to a monocentric, open label, randomized, two-way crossover pharmacokinetic study, with seven days washout period between the treatments. They received a single 81 mg oral dose of a test (new formulation) or a standard reference formulation of acetylsalicylic acid (Ecasil-81®) after about 8 h fasting. Blood samples were collected over a period of 36 h. The salicylic acid plasma concentration was evaluated by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Noncompartmental pharmacokinetic analysis was performed using the WinNonlin program. Results: The maximum plasma concentration (Cmax) of salicylic acid was 5433 and 5719 ng/mL reached in 3.66 and 4.02 h (tmax) for the test and the reference formulation, respectively. The 90% confidence interval of the ratios of geometric means of Cmax and area under curve of plasma concentration until the last concentration observed (AUC0- last) were within the interval 80-125%. Conclusion: The new acetylsalicylic acid formulation has a bioavailability equivalent to the reference formulation for the rate and the extent of absorption.

In this paper, we propose a new method for the recovery of a sparse signal from few linear measurements using a reference signal as side information. Modeling the signal coefficients with a double Laplace mixture model, and assuming that the distribution of the components of the prior information differs slightly from the unknown signal, the problem is formulated as a weighted l1 minimization problem. We derive sufficient conditions for perfect recovery and we show that our method is able to reduce significantly the number of measurements required for reconstruction. Numerical experiments demonstrate that the proposed approach outperforms the best algorithms for compressed sensing with prior information and is robust in imperfect scenarios.

In this paper, we propose a method for estimating the sparsity of a signal from its noisy linear projections without recovering it. The method exploits the property that linear projections acquired using a sparse sensing matrix are distributed according to a mixture distribution whose parameters depend on the signal sparsity. Due to the complexity of the exact mixture model, we introduce an approximate two-component Gaussian mixture model whose parameters can be estimated via expectation-maximization techniques. We demonstrate that the above model is accurate in the large system limit for a proper choice of the sensing matrix sparsifying parameter. Moreover, experimental results demonstrate that the method is robust under different signal-to-noise ratios and outperforms existing sparsity estimation techniques.

Publication in the conference proceedings of EUSIPCO, Lisbon, Portugal, 2014

International audience; A new lossy compression scheme for distributed and sparse sources under a low complexity encoding con- straint is proposed. This architecture is able to exploit both intra- and inter-signal correlations typical of sig- nals monitored, for example, by a wireless sensor net- work. In order to meet the low complexity constraint, the encoding stage is performed by a lossy distributed compressed sensing (CS) algorithm. The novelty of the scheme consists in the combination of lossy distributed source coding (DSC) and CS. More precisely, we pro- pose a joint CS reconstruction lter, which exploits the knowledge of the side information to improve the qual- ity of both the dequantization and the CS reconstruction steps. The joint use of CS and DSC allows to achieve large bit-rate savings for the same quality with respect to the non-distributed CS scheme, e.g. up to 1.2 bps in the cases considered in this paper. Compared to the DSC scheme (without CS), we observe a gain increasing with the rate for the same mean square error.

Publication in the conference proceedings of EUSIPCO, Glasgow, Scotland, 2009

Publication in the conference proceedings of EUSIPCO, Toulouse, France, 2002

Publication in the conference proceedings of EUSIPCO, Toulouse, France, 2002