2,942 research outputs found
Guido Davide Neri alla Pennsylvania State University tra il 1967 e il 1968
No full textGuido Davide Neri alla Pennsylvania State University tra il 1967 e il 1968.
Un incontro di amicizia e di filosofia. La filosofia, il suo modo di viverla, è stata al centro della personalità di
Guido Neri, anche quando si occupò di arte o di teoria e grafica politica, di mondi culturali a essa apparentemente
lontani; ma ha investito anche il suo modo di vivere la propria morte, nella saggezza e nella serenità
Statistical analysis of dynamic light scattering data: Revisiting and beyond the Schätzel formulas
No full textWe revisited the classical Schätzel formulas (K. Schätzel, Quantum Optics, 2, 1990) of the variance and covariance matrix associated to the normalized auto-correlation function in a Dynamic Light Scattering experiment when the sample is characterized by a single exponential decay function. Although thoroughly discussed by Schätzel who also outlined a correcting procedure, such formulas do not include explicitly the effects of triangular averaging that arise when the sampling time ∆t is comparable or larger than the correlation time τc. If these effects are not taken into account, such formulas might be highly inaccurate. In this work we have solved this problem and worked out two exact analytical expressions that generalize the Schätzel formulas for any value of the ratio ∆t/τc. By the use of extensive computer simulations we tested the correctness of the new formulas and showed that the variance formula can be exploited also in the case of fairly broad bell-shaped polydisperse samples (polydispersities up to ∼ 50−100%) and in connection with single exponential decay cross-correlation functions, provided that the average count rate is computed as the geometrical mean of the average count rates of the two channels. Finally, when tested on calibrated polystyrene particles, the new variance formula is able to reproduce quite accurately the error bars obtained by averaging the experimental data
Matched pairs and Yetter-Drinfeld braces
Full text linkIt is proven that a matched pair of actions on a Hopf algebra H is equivalent to the datum of a Yetter–Drinfeld brace, which is a novel structure generalising Hopf braces. This improves a theorem by Angiono, Galindo and Vendramin, originally stated for cocommutative Hopf braces. These Yetter–Drinfeld braces produce Hopf algebras in the category of Yetter–Drinfeld modules over H, through an operation that generalises Majid’s transmutation. A characterisation of Yetter–Drinfeld braces via 1-cocycles, in analogy to the one for Hopf braces, is given. Every coquasitriangular Hopf algebra H will be seen to yield a Yetter–Drinfeld brace, where the additional structure on H is given by the transmutation. We compute explicit examples of Yetter–Drinfeld braces on the Sweedler’s Hopf algebra, on the algebras E(n), on SLq(2), and an example in the class of Suzuki algebras
Occult nasolacrimal duct ectasia in a child with acute sinusitis: clinicopathological considerations and literature review
No full textEnlargement of the nasolacrimal duct (NLD) in the absence of neoplasm is rare. As there are few reports on this condition in the literature, its pathologic significance and proper management remain unclear. We report a case of asymptomatic NLD enlargement incidentally discovered on high resolution computed tomography scan performed for a complicated acute sinusitis
Brain Protection and Cognitive Function: Cocoa Flavonoids as Nutraceuticals
No full textCognitive decline and dementia are major public health social problems, suggesting the specific need to provide research into risk factors for cognitive decline as priority topic. Increasing evidence supports the hypothesis that oxidative stress and neuroinflammation might play a crucial role in the pathophysiology of cognitive decline. Further, cognitive dysfunction and dementia in Alzheimer's disease as well as in vascular dementia seem to be also the consequence of cerebral blood flow decrease and deregulation, also suggesting a putative pathophysiological convergence of mechanisms between atherosclerosis and Alzheimer's disease. In keeping with this, a growing interest has been addressed to flavonoids as potential nutraceuticals with neuroprotective effects. Of interest, cocoa beans have been described as a fundamental source of anti-oxidant flavonoids with the flavan-3-ols and their derivatives being present in high concentrations. Therefore, recent studies specifically focused on the favorable effects of flavonoid-rich cocoa and chocolate on cerebrovascular risk factors and cognitive function. Aim of this review is to summarize new findings concerning the cocoa effects on cognitive function, particularly focusing on some putative mechanisms of vascular and antioxidant action involved in preventing dementia
Brain protection and cognitive function. cocoa flavonoids as nutraceuticals
No full textCognitive decline and dementia are major public health social problems, suggesting the specific need to provide research into risk factors for cognitive decline as priority topic. Increasing evidence supports the hypothesis that oxidative stress and neuroinflammation might play a crucial role in the pathophysiology of cognitive decline. Further, cognitive dysfunction and dementia in Alzheimer's disease as well as in vascular dementia seem to be also the consequence of cerebral blood flow decrease and deregulation, also suggesting a putative pathophysiological convergence of mechanisms between atherosclerosis and Alzheimer's disease. In keeping with this, a growing interest has been addressed to flavonoids as potential nutraceuticals with neuroprotective effects. Of interest, cocoa beans have been described as a fundamental source of anti-oxidant flavonoids with the flavan-3-ols and their derivatives being present in high concentrations. Therefore, recent studies specifically focused on the favorable effects of flavonoid-rich cocoa and chocolate on cerebrovascular risk factors and cognitive function. Aim of this review is to summarize new findings concerning the cocoa effects on cognitive function, particularly focusing on some putative mechanisms of vascular and antioxidant action involved in preventing dementia
New insight into urate-related mechanism of cardiovascular damage
No full textSeveral experimental and clinical studies reported that hyperuricemia may trigger hypertension, metabolic syndrome, vascular damage and renal disease. Furthermore, a substantial proportion of epidemiological studies are compatible with the hypothesis that hyperuricemia may be an indipendent risk factor for cardiovascular disease as well as for an increased cardiovascular mortality. Xanthine oxidase is a critical source of reactive oxygen species contributing to vascular inflammation and endothelial dysfunction. Although a causal relationship between these conditions has not been clearly clarified, the capacity of uric acid to negatively affect vascular function by pro-oxidant effects and by decreasing nitric oxide bioavailability and consequently induce endothelial dysfunction may explain the association among hyperuricemia, hypertension, metabolic syndrome, and cardiovascular disease, also by a common mechanicistic point of view
New Insight into Urate-Related Mechanism of Cardiovascular Damage
No full textSeveral experimental and clinical studies reported that hyperuricemia may trigger hypertension, metabolic syndrome, vascular damage and renal disease. Furthermore, a substantial proportion of epidemiological studies are compatible with the hypothesis that hyperuricemia may be an indipendent risk factor for cardiovascular disease as well as for an increased cardiovascular mortality. Xanthine oxidase is a critical source of reactive oxygen species contributing to vascular inflammation and endothelial dysfunction. Although a causal relationship between these conditions has not been clearly clarified, the capacity of uric acid to negatively affect vascular function by pro-oxidant effects and by decreasing nitric oxide bioavailability and consequently induce endothelial dysfunction may explain the association among hyperuricemia, hypertension, metabolic syndrome, and cardiovascular disease, also by a common mechanicistic point of view
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