Studio sui fondamenti teorici dell'effetto termoelastico nei materiali metallici

Heating and cooling of a solid material as a result of its elastic deformation is called thermoelastic effect. This work’s objective is to illustrate how thermoelastic effect can be analyzed and calculated through the methods of Continuum Mechanics. Special attention is paid to the main points of the theory and hypotheses made. The work ends with simple numerical examples about metals. The treatment is general, however only for linear, homogenous, isotropic case an explicit analysis is shown. In this context emerges that: • The volumetric dilatation rate is the macroscopic cause of temperature change and can be fictitiously viewed as a volumetric heat generation. • The theory leads to a coupled initial-boundary-value problem of four linear partial differential equations where temperature and three components of displacement are the unknowns. • Adiabatic assumption allows remarkable simplifications of the mathematical problem. • The theory is able to predict vibration damping. _____________________________________________________________________________ Il riscaldamento e raffreddamento di un materiale solido a seguito di una deformazione elastica è detto effetto termoelastico. L’obiettivo di questo studio è illustrare in che modo, attraverso i metodi della Meccanica dei Continui, è possibile studiare l’effetto termoelastico e ricavare un modello matematico adatto a prevederlo. Particolare attenzione viene rivolta ai passaggi fondamentali della teoria e alle ipotesi introdotte. Il lavoro si conclude con semplici esempi numerici relativi ad alcuni materiali metallici. La trattazione è generale, tuttavia viene analizzato in modo esplicito solo il caso lineare, omogeneo e isotropo. In questo contesto emerge che: • Il rate di deformazione volumica rappresenta la causa macroscopica della variazione di temperatura e può essere fittiziamente considerato come una generazione volumica di calore. • La teoria conduce ad un sistema di quattro equazioni differenziali alle derivate parziali, lineari, completamente accoppiate, in cui le incognite sono la temperatura e le tre componenti di spostamento. • Lipotesi di adiabaticità della deformazione, quando applicabile, permette di semplificare notevolmente il problema matematico. • La teoria è in grado di prevedere lo smorzamento delle vibrazioni

Positive effect of nutraceuticals on sperm DNA damage in selected infertile patients with idiopathic high sperm DNA fragmentation

The use of nutraceuticals to improve sperm parameters and male fertility is debatable, even if evidence suggests that selected infertile patients might benefit from their use. In particular, oxidative stress might play a role in idiopathic male infertility, leading to sperm membrane damage and high sperm DNA fragmentation (SDF). The aim of this study was to evaluate, in selected idiopathic infertile men with high SDF, the effect on sperm DNA damage and on standard semen parameters of a nutraceutical formulation containing myoinositol, alpha lipoic acid, coenzyme Q10, selenium, zinc and B vitamins

MUSCARINIC RECEPTORS STIMULATE CELL PROLIFERATION IN THE HUMAN UROTHELIUM-DERIVED CELL LINE UROtsa

The widespread non-neuronal synthesis of acetylcholine (ACh) has changed the paradigm of ACh acting solely as a neurotransmitter. Indeed, the presence of ACh in many types of proliferating cells suggests a role for this neurotransmitter in the control of cell division. The parasympathetic system is a major pathway regulating micturition, but ACh-mediated control plays a more complex role than previously described, acting not only in the detrusor muscle, but also influencing detrusor function through the activity of urothelial muscarinic receptors. Here we investigated the role of muscarinic receptors in mediating cell proliferation in the human UROtsa cell line, which is a widely used experimental model to study urothelium physiology and pathophysiology. Our results demonstrate that UROtsa cells express the machinery for ACh synthesis and that muscarinic receptors, with the rank order of M3>M2>M5>M1=M4, are present and functionally linked to their known second messengers. Indeed, the cholinergic receptor agonist carbachol (CCh) (1-100 μM) concentration-dependently raised IP(3) levels, reaching 66±5% over basal. The forskolin-mediated adenylyl cyclase activation was reduced by CCh exposure (forskolin: 1.4±0.14 pmol/ml; forskolin+100 μM CCh: 0.84±0.12 pmol/ml). CCh (1-100 μM) concentration-dependently increased UROtsa cell proliferation and this effect was inhibited by the non-selective antagonist atropine and the M(3)-selective antagonists darifenacin and J104129. Finally, CCh-induced cell proliferation was blocked by selective PI-3 kinase and ERK activation inhibitors, strongly suggesting that these intracellular pathways mediate, at least in part, the muscarinic receptor-mediated cell proliferatio