RESUMEN
The performance of porous scaffolds for tissue engineering (TE) applications is evaluated, in general, in terms of porosity, pore size and distribution, and pore tortuosity. These descriptors are often confounding when they are applied to characterize transport phenomena within porous scaffolds. On the contrary, permeability is a more effective parameter in (1) estimating mass and species transport through the scaffold and (2) describing its topological features, thus allowing a better evaluation of the overall scaffold performance. However, the evaluation of TE scaffold permeability suffers of a lack of uniformity and standards in measurement and testing procedures which makes the comparison of results obtained in different laboratories unfeasible. In this review paper we summarize the most important features influencing TE scaffold permeability, linking them to the theoretical background. An overview of methods applied for TE scaffold permeability evaluation is given, presenting experimental test benches and computational methods applied (1) to integrate experimental measurements and (2) to support the TE scaffold design process. Both experimental and computational limitations in the permeability evaluation process are also discussed.
Asunto(s)
Modelos Teóricos , Ingeniería de Tejidos , Andamios del Tejido , Animales , Humanos , PermeabilidadRESUMEN
The ticket, once considered just dissuasive or control instrument, has become citizens sharing of the costs of activities, services and performance of NHS. The difficult economic situation, that applies the main European countries, is leading in Italy to an increase measures of copayment. The use of over-sharing may drive, however, to important consequences in terms of equity, efficiency and cost containment of health. Copayment does not reduce the overall burden of spending, because often counterbalanced by a concomitant increase in private spending. In fact, Italian private expenditure on health "out of pocket" is the highest in Europe and more Italians discover the "low cost health care." The Authors propose to limite the introduction of new ticket or exacerbate the existing, focusing on the adherence of citizens to health and social integrative funds, that are now present on the national scene with about 5 million of members.
Asunto(s)
Control de Costos/organización & administración , Seguro de Costos Compartidos/tendencias , Atención a la Salud/economía , Costos de la Atención en Salud/tendencias , Control de Costos/legislación & jurisprudencia , Control de Costos/normas , Seguro de Costos Compartidos/legislación & jurisprudencia , Seguro de Costos Compartidos/normas , Europa (Continente) , ItaliaRESUMEN
The pars distalis from the pituitary gland of adult male ruin lizards (Podarcis sicula campestris De Betta), captured during the five periods of the annual sexual cycle (emergence from hibernation, reproductive period, summer regression, autumnal recrudescence, winter arrest), was studied immunohistochemically using specific antibodies against hFSHbeta, hLHbeta, oFSHbeta, and oLHbeta with the avidin-biotin complex (ABC) procedure to monitor the seasonal changes in shape, size and percentage area taken up from gonadotropes. FSH containing cells were specifically identified with anti-hFSHbeta and anti-oFSHbeta sera, whereas the LH cells were localized by anti-hLHbeta. The anti-oLHbeta serum showed cross-reactivity with the cells immunostained by the three above antisera (anti-hFSHbeta, anti-oFSHbeta, and anti-hLHbeta). None of the cells contained both gonadotropic hormones as shown by the double-immunostaining procedure. Generally, FSH cells were larger and more numerous than LH cells. FSH cells were elongated or pyriform in shape from spring to autumn, whereas they were round or oval during the winter stasis and until the emergence from hibernation. The size and the percentage area occupied by FSH cells showed an annual pattern with two distinct peaks in the reproductive and in the autumnal recrudescence periods. LH cells did not show seasonal changes in shape, being round or oval throughout the reproductive cycle, whereas their size and the area they occupied underwent seasonal variations. The LH cells reached the largest size during the reproductive period and the smallest size during the summer regression. The percentage area occupied by LH cells in the pars distalis peaked at the emergence from hibernation and during the summer refractory period, when FSH cells displayed their lowest values.