186,727 research outputs found
Opusculum in quo una oratio, & duae questiones: altera de certitudine, & altera de medietate mathematicarum continentur
No full text[Francesco Barozzi]Exlibrisstempel: nicht entzifferbar 005213081_0001 Exemplar der ETH-BI
Il vescovo e le scienze: sull’insegnamento nell’Ateneo di Padova tra Quattrocento e Cinquecento
No full textEsame della figura del Barozzi, descritto da contemporanei come cultore di scienze matematiche, sullo sfondo dell'insegnamento matematico nell'Ateneo padovano tra '400 e primo '50
Saccule and tinnitus: a possible connection?
No full textThe saccule is the most mysterious organ of the labyrinth and, for this reason, one of the most fascinating.
For anatomic, embryologic and physiologic reasons the saccule has both auditory and vestibular characteristics, being the connecting link between the vibratory energy and the vestibular response: it is an anatomic bridge between the anterior and the posterior labyrinth; it has a common embryologic origin with the cochlea in the pars inferior of the labyrinth; it is the main hearing organ in fish and other ancestral vertebrates.
The saccule is an otolith organ involved in vertical linear movement detection and sensing gravitational changes; it controls the tonic components of the antigravity muscles contributing to the postural control. In addition, through the vestibule-sympathetic reflexes, it contributes to the control of blood pressure during movement and through postural changes.
The aim of this presentation is to show why the saccule should be taken into consideration for certain forms of tinnitus.
The anatomical proximity of the saccule to the stapes suggests that an excessive pressure on the footplate may damage the saccular neuroepithelium which lies close to the oval window.
The principal mechanisms suspected of being involved in saccular dysfunction are:
• chronic noise exposure [1,2].
• tonic tensor tympani contraction [3]
• Disturbance of blood circulation, aging, trauma.
While the effects of detached utricular otoconia are generally accepted as the cause of Benign Paroxysmal Positional Vertigo, what happens to saccular otoconia?
Gussen (1980) reported that a suffering saccular macula dislodges otolith debris that could reach the cochlea through the ductus reuniens and cochlear duct, thus also affecting the cochlear base and the high frequency hearing thresholds.[4]
An intermittent tinnitus has been described in patients with by BPPV, in the same ear affected by the lithiasis (Barozzi et al. 2014)[5]
Recently detached saccular otoconia have even been suggested as pathophysiological cause of Ménière disease (Hornibrook and Bird, 2017) [6,7].
We suggest that saccular debris can fall into the ductus reuniens and thereby disturb the endolymphatic flow in the cochlear base. This event can play a role in some ear symptoms, such as certain cases of tinnitus, fullness, mild vertigo/nausea, slight hearing loss or Ménière-like findings in patients with asymmetric VEMPs.
A possible role of the saccule should be considered in tinnitus.
This also corroborates the theory of the evolutionary basis of tinnitus as stimulus of alertness or vigilance that may have survival value; as the saccule controls the tonic components of the antigravity muscles, it could therefore participate in “fight or flight” responses.[8]
Based on these considerations, a cooperation between specialists of various disciplines (neurootologists, radiologists, neurophysiologists, cardiologists and dentists)would be beneficial to fully characterize the role of the vestibular organ on tinnitus
Prolusione
No full textSi illustra la figura di Pietro Barozzi, vescovo di Padova, nel contesto della storia del Rinascimento e della riforma della Chiesa
La produzione aurificiaria e gli orefici dell’età di Barozzi
No full textIl contributo presenta una mappatura degli orefici principali di Padova nella seconda metà del Quattrocento. L'indagine è stata condotta sulla base dei documenti d'archivio ed ha evidenziato quali fossero le personalità più in vista e rilevanti del periodo, valutando gli estimi, i testamenti e le commissioni ricevute, in particolare dal vescovado
Numerical Predictions for Stable Buoyant Regimes within a Square Cavity Containing a Heated Horizontal Cylinder
No full textBuoyancy-induced flow regimes are investigated numerically for the basic case of a horizontal cylinder centred into a long co-axial square-sectioned cavity. In the frame of the 2D assumption, the treshold for the occurrence of time-dependent behaviour is explored. Stable symmetric and non-symmetric steady-state solutions, as well as unsteady regimes are observed, depending on the Rayleigh number, Ra, and the aspect ratio of the cavity, d. Four d-values are considered (d = .2, .4, .6, and .8). Heat transfer results are correlated by a single equation covering the full subcritical region
Un metodo di analisi delle condizioni delle sponde di un corso d’acqua di pianura applicato al basso corso del Fiume Adda (Lombardia, Italia).
No full text
Pigmentary system of the adult alpine Salamander Salamandra atra atra (Laur., 1768)
No full textThe pigmentary system of the skin from adult specimens of the black alpine salamander Salamandra atra atra was investigated by light microscope, electron microscope, and biochemical studies. Results were compared with those obtained in previous study of the subspecies Salamandra atra aurorae. Unlike Salamandra atra aurorae, which presents epidermal xanthophores and iridophores, Salamandra atra atra is completely melanized, presenting only epidermal and dermal melanophores. The melanosomes in both the epidermis and the dermis appear to derive from a multivesicular premelanosome similar to that in the goldfish, and the epidermal melanosomes are smaller than those in the dermis. Premelanosomes with an internal lamellar matrix were not observed. The biochemical results have shown that in the ethanol extracts obtained from the skin in toto and from the melanosomes, pteridines and flavins are always present and are the same as those extracted from the black skin areas of Salamandra atra aurorae
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