704 research outputs found

    Evidence for narrow resonant structures at W1.68W \approx 1.68 and W1.72W \approx 1.72 GeV in real Compton scattering off the proton

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    First measurement of the beam asymmetry Σ\Sigma for Compton scattering off the proton in the energy range Eγ=0.851.25E_{\gamma}=0.85 - 1.25 GeV is presented. The data reveals two narrow structures at Eγ=1.036E_{\gamma}= 1.036 and Eγ=1.119E_{\gamma}=1.119 GeV. They may signal narrow resonances with masses near 1.681.68 and 1.721.72 GeV, or they may be generated by the sub-threshold KΛK\Lambda and ωp\omega p production. Their decisive identification requires additional theoretical and experimental efforts.Comment: Published versio

    MR imaging of entrapment neuropathies of the shoulder

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    LEARNING OBJECTIVES: To describe the MRI features of most common entrapment neuropathies of the shoulder: - Parsonage-Turner syndrome - quadrilateral space syndrome (axillary neuropathy) - suprascapular nerve syndrome BACKGROUND: Entrapment neuropathies are characterized by alteration of nerve function secondary to compression by mechanical or dynamic forces. The compression may be acute, chronic or intermittent. Not infrequently compressive neuropathies are related to space-occupying lesions such as tumors, cysts, inflammatory processes, or post-traumatic conditions. IMAGING FINDINGS: The MR imaging appearance of Parsonage-Turner syndrome is quite characteristic, with marked edema in the affected muscles of the shoulder, most commonly those innervated by the suprascapular nerve, although deltoid muscle can also be compromised. MR imaging of quadrilateral space syndrome may reveal fatty atrophy or edema isolated to the teres minor muscle. MR imaging of suprascapular nerve syndrome is established when edema or fatty changes of supraspinatus and/or infraspinatus muscle is present along with a cyst or ganglion in the spinoglenoid or suprascapular notch. CONCLUSION: MRI is a powerful diagnostic imaging tool in the diagnosis of entrapment neuropathies of the shoulder and underlying causes, thus excluding other possible causes of shoulder pain. Moreover, MRI may recognize active changes of denervation in muscle from chronic denervation muscle changes or “fatty atrophy” in isolation, and therefore it may change treatment and management

    Stochastic Resonance in Two Dimensional Landau Ginzburg Equation

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    We study the mechanism of stochastic resonance in a two dimensional Landau Ginzburg equation perturbed by a white noise. We shortly review how to renormalize the equation in order to avoid ultraviolet divergences. Next we show that the renormalization amplifies the effect of the small periodic perturbation in the system. We finally argue that stochastic resonance can be used to highlight the effect of renormalization in spatially extended system with a bistable equilibria

    Development and characterization of an amorphous solid dispersion of furosemide in the form of a sublingual bioadhesive film to enhance bioavailability

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    Administered by an oral route, Furosemide (FUR), a diuretic used in several edematous states and hypertension, presents bioavailability problems, reported as a consequence of an erratic gastrointestinal absorption due to various existing polymorphic forms and low and pH-dependent solubility. A mucoadhesive sublingual fast-dissolving FUR based film has been developed and evaluated in order to optimize the bioavailability of FUR by increasing solubility and guaranteeing a good dissolution reproducibility. The Differential Scanning Calorimetry (DSC) analyses confirmed that the film prepared using the solvent casting method entrapped FUR in the amorphous state. As a solid dispersion, FUR increases its solubility up to 28.36 mg/mL. Drug content, thickness, and weight uniformity of film were also evaluated. The measured Young\ue2\u80\u99s Modulus, yield strength, and relative elongation of break percentage (EB%) allowed for the classification of the drug-loaded film as an elastomer. Mucoadhesive strength tests showed that the force to detach film from mucosa grew exponentially with increasing contact time up to 7667 N/m2. FUR was quickly discharged from the film following a trend well fitted with the Weibull kinetic model. When applied on sublingual mucosa, the new formulation produced a massive drug flux in the systemic compartment. Overall, the proposed sublingual film enhances drug solubility and absorption, allowing for the prediction of a rapid onset of action and reproducible bioavailability in its clinical application

    Large-Eddy simulation of pulsatile blood flow

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    Large-Eddy simulation (LES) is performed to study pulsatile blood flow through a 3D model of arterial stenosis. The model is chosen as a simple channel with a biological type stenosis formed on the top wall. A sinusoidal non-additive type pulsation is assumed at the inlet of the model to generate time dependent oscillating flow in the channel and the Reynolds number of 1200, based on the channel height and the bulk velocity, is chosen in the simulations. We investigate in detail the transition-to-turbulent phenomena of the non-additive pulsatile blood flow downstream of the stenosis. Results show that the high level of flow recirculation associated with complex patterns of transient blood flow have a significant contribution to the generation of the turbulent fluctuations found in the post-stenosis region. The importance of using LES in modelling pulsatile blood flow is also assessed in the paper through the prediction of its sub-grid scale contributions. In addition, some important results of the flow physics are achieved from the simulations, these are presented in the paper in terms of blood flow velocity, pressure distribution, vortices, shear stress, turbulent fluctuations and energy spectra, along with their importance to the relevant medical pathophysiology

    Force balance and membrane shedding at the Red Blood Cell surface

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    During the aging of the red-blood cell, or under conditions of extreme echinocytosis, membrane is shed from the cell plasma membrane in the form of nano-vesicles. We propose that this process is the result of the self-adaptation of the membrane surface area to the elastic stress imposed by the spectrin cytoskeleton, via the local buckling of membrane under increasing cytoskeleton stiffness. This model introduces the concept of force balance as a regulatory process at the cell membrane, and quantitatively reproduces the rate of area loss in aging red-blood cells.Comment: 4 pages, 3 figure
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