702 research outputs found

    Eosinophilic granulomatosis with polyangiitis (EGPA) and PRES: a case-based review of literature in ANCA-associated vasculitides

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    Eosinophilic granulomatosis with polyangiitis (EGPA) is a small-sized vessel systemic necrotizing vasculitis and belongs to the family of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides. The involvement of central nervous system in this condition is pretty rare. Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological entity described for the first time by Hinchey et al. (N Engl J Med 334(8):494-500, 1996) and characterized by MRI findings of reversible subcortical vasogenic edema predominantly in the white matter of posterior cerebral lobes. There are few case reports describing the concurrence of PRES with ANCA-associated vasculitides. We describe a case of PRES in a patient with a diagnosis of EGPA with a concise review of the literature. The exact cause of this syndrome is unknown. It has been related to eclampsia, drug-induced hypertension, renal insufficiency and also to rheumatologic diseases. Endothelial injury, hypertension and immunosuppressive medications can compromise the regulation of cerebral blood flow. In ANCA-associated vasculitides, patients presenting with symptoms of PRES represent a challenge to treatment with immunosuppressive medications. However, since an inflammatory process might be implicated, judicious use of these agents along with tight control of blood pressure and a supportive therapy may contribute to the resolution of the encephalopathic syndrome treating at the same time other manifestation related to the rheumatologic disease. Larger clinical studies are warranted to optimize the management of vasculitis-associated PRES

    FIRST RECORD OF DUGONGIDAE (MAMMALIA: SIRENIA) FROM THE FLORESTA CALCARENITES FORMATION (LATE BURDIGALIAN – EARLY LANGHIAN, REGGIO CALABRIA, SOUTHERN ITALY)

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    A sirenian rib has been recovered at Motta San Giovanni (Reggio Calabria) in the “Floresta Calcarenites”, a Formation cropping out in Sicily and Calabria and dated late Burdigalian-Langhian. Although the rib is not a diagnostic bone for taxonomy, its presence in southern Calabria extends the knowledge about the paleobiogeography of the Family Dugongidae in the Mediterranean basin. The find is hitherto the only record of sirenians in the Floresta calcarenites. Moreover, the specimen extends back to the Early-Middle Miocene (late Burdigalian-Langhian) the occurrence of sirenians in Calabria, previously determined thanks to substantial material from the Late Miocene (Tortonian) of the Monte Poro area (Vibo Valentia).  The paleoenvironment of the Floresta calcarenites was a warm and shallow sea, consistent with the paleoecology of Dugongidae

    Enhanced lipid extraction from unbroken microalgal cells using enzymes

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    The marine microalga Nannochloropsis sp. was chosen as a model organism to investigate the feasibility of using cell wall-degrading enzymes to enhance the recovery of intracellular lipids. An enzyme cocktail containing galactomannanase, 1,4-β-cellobiosidase and β-glucosidase as main components was prepared from commercial enzyme preparations. The effects of pretreatment time (P), enzyme dosage (D), pH and temperature (T) on the amount of extracted lipids were investigated using response surface methodology. Under the best conditions (P = 90 min, D = 1.3 mg g–1, pH = 5, T = 36°C) over 70% of the lipids present in the microalga were recovered. SEM and TEM characterization of enzyme-treated microalgae showed extensive cell damage with significant disruption of the cell wall and release of algal material. Overall, the results of this study strongly support the use of commercial enzyme preparations to improve lipid recovery from microalgae and provide useful information on the influence of process conditions on the treatment efficiency

    In systemic sclerosis skin perfusion of hands is reduced and may predict the occurrence of new digital ulcers

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    Systemic sclerosis (SSc) patients are at high risk for the development of ischemic digital ulcers (DUs). The aim of this study was to assess in SSc patients a correlation between skin perfusion evaluated by LDPI and DUs and to evaluate the prognostic value of skin perfusion to predict the new DUs occurrence. Fifty eight (47 female, 11 male) SSc patients were enrolled. Skin perfusion of hands and region of interest (ROIs) was measured by Laser Doppler perfusion Imager (LDPI). The proximal-distal gradient (PDG) was present when the perfusion mean difference between ROI1 and ROI2 was > 30 pU. The skin perfusion of hands is lower in SSc patients than in healthy controls. The skin perfusion decreased with severity of capillaroscopic damage. Both mean perfusion of hand and PDG are significantly (p < 0.01 and p < 0.0001, respectively) lower in SSc patients with new DUs than in SSc patients without DUs. Only 2 of 11 SSc patients (18.2%) with PDG developed new digital ulcers, conversely 36 of 47 (76.6%) SSc patients without PDG developed new digital ulcers (p < 0.001). The ROC curves demonstrated a good accuracy of new DUs prediction for PDG (0.78, p < 0.0001). Using this cut-off value of 30 pU, RR for new DUs development in SSc patients without PDG is 4,2 (p < 0.001). LDPI indices could be used in association to the capillaroscopic and clinical findings or serological tests in the identification of patients at high risk of developing DU

    Constraint-Based Visual Generation

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    In the last few years the systematic adoption of deep learning to visual generation has produced impressive results that, amongst others, definitely benefit from the massive exploration of convolutional architectures. In this paper, we propose a general approach to visual generation that combines learning capabilities with logic descriptions of the target to be generated. The process of generation is regarded as a constrained satisfaction problem, where the constraints describe a set of properties that characterize the target. Interestingly, the constraints can also involve logic variables, while all of them are converted into real-valued functions by means of the t-norm theory. We use deep architectures to model the involved variables, and propose a computational scheme where the learning process carries out a satisfaction of the constraints. We propose some examples in which the theory can naturally be used, including the modeling of GAN and auto-encoders, and report promising results in problems with the generation of handwritten characters and face transformations

    Combined use of volumetric expanders and Scheffler receivers to improve the efficiency of a novel direct steam solar power plant

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    This research proposes an innovative solar thermal plant able to generate mechanical power through an optimized system of heliostats with Scheffler-type solar receivers coupled with screw-type steam expanders. Scheffler receivers appear to perform better than parabolic trough collectors due to the high compactness of the focal receiver, which minimizes convective and radiative heat losses even at high vaporization temperatures. At the same time, steam screw expanders are volumetric machines that can be used to produce mechanical power with satisfactory efficiency also by admitting two-phase mixtures and with further advantages compared to steam turbines: low working fluid velocities, low operating pressures, and avoidance of overheating. This study establishes a mathematical model to assess the energetic advantages of the planned solar thermal power system by evaluating the solar-to-electricity efficiency for different off-design working conditions. For this purpose, a numerical model on the Scheffler receiver is initially investigated, thus assessing all the energy losses which affect the heat transfer phase. A thermodynamic model is then developed to evaluate the energy losses and performance of the screw expander under real working conditions. Finally, parametric optimization of the solar energy conversion is performed in a wide range of operating conditions by establishing thermodynamic formulations related to the whole solar electricity generation system. Water condensation pressure and vaporization temperature are so optimized with respect to global energy conversion efficiency which, under the best operating conditions achieved in this research, rises from 10.9% to 14.4% with increasing solar irradiation intensity. Hence, the combined use of screw expanders and Scheffler receivers for solar thermal power system application can be a promising technology with advantages over parabolic dish concentrators. Novelty statement: This research proposes an innovative direct steam solar power plant based on an SRC, with water utilized as both heat transfer and working fluid, equipped with Scheffler solar receivers as a thermal source and screw expanders as work-producing devices. Technical studies and energy assessments of this kind of SEGS at part-load operation do not exist in scientific literature; after reviewing the literature, it was determined that volumetric expanders have been rarely combined with Scheffler receivers for solar thermal power system application. In effect, combined use of screw expanders and Scheffler-type solar concentrator in a direct steam solar power system represents a completely new plant configuration; however, as a promising DSG solar system, at present numerical model of this new sort of SEGS is lacked in literature and the optimum operating conditions have yet to be defined. For this reason, the chief objective of this paper is to define a first parametric optimization of all thermodynamic variables involved to maximize global efficiency of the proposed solar thermal power generation system for ordinary working conditions
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