Le meraviglie di Roma antica e moderna: vedute, ricostruzioni, progetti nelle raccolte della Biblioteca di Archeologia e Storia dell'Arte; catalogo della mostra

Saggio su Rodolfo Lanciani archeologo e collezionista di disegni. Cura scientifica degli 80 disegni su Roma più significativi esposti nella mostra (Pirro Ligorio, G. B. Piranesi, A. Specchi, G. B. Nolli)

Protective effect of S-Adenosyl-L-Methionine in hepatic uroporphyria. Evaluation in an experimental model.

The potential use of S-adenosyl-L-methionine (SAMe) as therapy for human porphyria cutanea tarda was investigated in an experimental model of hepatic porphyria - that is, chronic treatment of female rats with 0.2% hexachlorobenzene (HCB) in the diet. Administration of SAMe (25 mg/kg subcutaneously twice daily) during the last 15 days of HCB administration halved porphyrin accumulation in the liver but did not alter HCB-induced massive inhibition of uroporphyrinogen decarboxylase. Equally unaffected were inhibition of glutathione peroxidase and stimulation of lipid peroxide formation induced by HCB. Hypothetically, the beneficial effect of SAMe on hepatic prophyrin accumulation might be linked to modifications of the cellular availability of adenosine triphosphat

Shape Memory Alloy—Polymer Composites: Static and Fatigue Pullout Strength under Thermo-Mechanical Loading

This work was carried out within the context of an R&D project on morphable polymer matrix composites (PMC), actuated by shape memory alloys (SMA), to be used for active aerodynamic systems in automotives. Critical issues for SMA–polymer integration are analyzed that are mostly related to the limited strength of metal–polymer interfaces. To this aim, materials with suitable thermo-mechanical properties were first selected to avoid premature activation of SMA elements during polymer setting as well as to avoid polymer damage during thermal activation of SMAs. Nonstandard samples were manufactured for both static and fatigue pullout tests under thermo-mechanical loading, which are made of SMA wires embedded in cylindrical resin blocks. Fully coupled thermo-mechanical simulations, including a special constitutive model for SMAs, were also carried out to analyze the stress and temperature distribution in the SMA–polymer samples as obtained from the application of both mechanical loads and thermal activation of the SMA wires. The results highlighted the severe effects of SMA thermal activation on adhesion strength due to the large recovery forces and to the temperature increase at the metal–polymer interface. Samples exhibit a nominal pullout stress of around 940 MPa under static mechanical load, and a marked reduction to 280 MPa was captured under simultaneous application of thermal and mechanical loads. Furthermore, fatigue run-out of 5000 cycles was achieved, under the combination of thermal activation and mechanical loads, at a nominal stress of around 200 MPa. These results represent the main design limitations of SMA/PMC systems in terms of maximum allowable stresses during both static and cyclic actuation

Bile and biliary lipid secretion in rats with hexachlorobenzene-induced porphyria. Effect of S-Adenosyl-L-Methionine administration.

We investigated liver morphology and biliary function in vivo in rats made porphyric by hexachlorobenzene (HCB). In one group of HCB rats were also evaluated whether S-adenosyl-L-methionine (SAMe), administered during the last 15 days of HCB treatment, attenuated liver injury and the accumulation of porphyrins (HCB + SAMe group). In HCB rats we found: (a) a 100% increase in liver weight; (b) a 500-fold increase in total liver porphyrins (TLP); (c) significantly increase serum bilirubin and cholesterol levels; (d) unchanged total bile flow (TBF) but enhanced levels of the bile acid independent fraction (BAIF); and (e) decreased excretion in bile of bile acids (BA), phospholipids (PL) and cholesterol (CHO) (58, 65 and 47%, respectively, expressed as mmol/min per kg liver). SAMe was found to partially reverse HCB-related effects. TLP levels were about 65% lower in HCB + SAMe treated rats than in HCB rats. However, while SAMe restored bile CHO excretion to control values, it did not influence bile excretion of BA, PL, or BAIF. In conclusion, HCB-induced porphyria was characterized by a complex derangement of liver morphology and biliary function that was unrelated to the extent of porphyrin accumulation in the live