197,825 research outputs found
Fatigue in multiple sclerosis: Does the functional or structural damage prevail?
No full textFatigue in multiple sclerosis (MS) is a highly invalidating symptom, lacking efficacious drugs. This topical review aims at assessing the signs in the literature of functional versus structural damage prevalence at the origin of MS fatigue by focusing on papers that assessed the two counterparts in the same patients, paying attention that the fatigue levels do not correlate with clinical severity. We summarize and discuss evidence of increased levels of fatigue occurring together with the alterations of functional connectivity at multiple levels, in the absence of any relationship with lesion load and local atrophy of the involved structures. Specifically, neuronal communication mainly altered in the corticomuscular synchronizations, between hemispheric homologs and in the resting-state networks involved in emotion (cingulate cortex) and effort-reward balance (striatum and inferior parietal lobule). Finally, given the functional prevalence in neuronal network alterations at the origin of fatigue in MS, we highlight the relevance of developing treatments aiming at compensating the neuronal electric communication dysfunctions
Transcranial pulsed Doppler in the diagnosis of cerebrovascular pathology: methodology, indications and limitations
No full textDoppler analysis of flow in intracranial arteries is now possible using a 2 MHz probe, allowing sufficient penetration of bone to obtain signals noninvasively and to measure rate of flow in middle (MCA), anterior (ACA) and posterior (PCA) cerebral arteries and in basilar trunk. Practical applications of this new method are numerous in cerebrovascular disease and, despite certain limitations due to anatomic factors, transcranial Doppler may identify stenosis of the intracranial arteries and study the value of collateral flow across the anterior circle of Willis in patients with extracranial carotid artery stenosis
Symptomatyc subtotal occlusion of the innominate artery treated with balloon angioplasty and stenting
No full textPurpose: To report the endovascular treatment of a subtotal occlusion of the innominate artery giving rise to subclavian steal syndrome. Methods and Results: A 60-year-old man in general good health was admitted to the hospital for sudden onset of amaurosis in the right eye. Thrombosis of the central retinal artery was diagnosed. Physical examination, color flow duplex imaging, and aortic arch angiography showed a subtotal occlusion of the innominate artery with right subclavian steal syndrome. One month later, balloon dilation and stenting of the innominate artery was performed through a right axillary access without cerebral protection. The innominate artery was recanalized with correction of the steal syndrome and restoration of the right radial pulse; no complications occurred. Twelve months later, color flow duplex sonography confirmed innominate stent patency and antegrade flow in the right vertebral artery. Conclusions: Our experience supports the view that percutaneous endovascular techniques are appropriate and are the preferred treatment for lesions of the supra-aortic vessels. Continued surveillance will determine their long-term durability
Pounding Effects in Simply Supported Bridges Accounting for Spatial Variability of Ground Motion: A Case Study
No full textThis study carries out a parametrical analysis of the seismic response to asynchronous earthquake ground motion of a long multispan rc bridge, the Fener bridge, located on a high seismicity area in the north-east of Italy. A parametrical analysis has been performed investigating the influence of the seismic input correlation level on the structural response: a series of nonlinear time history analyses have been executed, in which the variation of the frequency content in the accelerograms at the pier bases has been described by considering the power spectral density function (PSD) and the coherency function (CF). In order to include the effects due to the main nonlinear behaviours of the bridge components, a 3D finite element model has been developed, in which the pounding of decks at cap-beams, the friction of beams at bearings, and the hysteretic behaviour of piers have been accounted for. The sensitivity analysis has shown that the asynchronism of ground motion greatly influences pounding forces and deck-pier differential displacements, and these effects have to be accurately taken into account for the design and the vulnerability assessment of long multispan simply supported bridges
Ecosistemes profunds de la Mediterrània: Biodiversitat, funcionament i vulnerabilitat
No full textMemoria de tesis doctoral presentada por Samuele Tecchio para optar al grado de Doctor en Biodiversidad por la Universitat de Barcelona (UB), realizada bajo la dirección del Dr. Francisco Sardà Amills y de la Dra. Eva Zoe Ramírez Llodra del Institut de Ciències del Mar (ICM-CSIC).-- 138 pagesThe deep sea is the portion of the ocean that stands below 200 m depth, both in the water column and in the benthos (Gage & Tyler 1991). It is the largest biome of planet Earth, with about 90% of the ocean area being deep sea (Ramírez-Llodra et al. 2010a). In the past decades, researchers have loved to refrain that “we know more about the surface of the Moon than about our deep oceans”. To date, this still holds true. The deep sea is considered impenetrable, difficult and expensive to reach and observe. [...]The author has been financed by a JAE pre-doctoral grant from the Spanish Research Council (CSIC), from December 2008 to November 2012. This work has been carried out in the framework of the following research projects:
- BIOFUN (CTM2007-28739-E), from the European Science
Foundation (ESF);
- PROMETEO (CTM2007-66316-C02/MAR), from the
CYCIT, Spain;
- HERMIONE (G.A. 226354), from the European UnionPeer reviewe
UN CASO DI FISTOLA PANCREATICA, INSORTA DOPO INTERVENTO DI RESEZIONE GASTRICA, TRATTATA CON SOMATOSTATINA
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