Symposium: Italian Industrial Districts In The I99Os

This paper reviews the scholarship concerning the rise to economic prominence of the Italian industrial districts, and the causes of some of the difficulties in which some districts have found themselves since the mid-1980s. The paper develops the main lines of the economic advantages that districts enjoyed during a period of rapid growth, resulting from the operation of a market in common which blends competition and cooperation. The effects of globalisation are changing this somewhat ‘idyllic’ picture, as the structure of linkages between firms comes under pressure. Prospects for the Italian districts in these new circumstances are discussed.     

From hospital to municipal cogeneration systems: an Italian case study

A mixed integer linear programming model combined with a more traditional design by scenarios is proposed to optimize facilities size and operation mode of a municipal energy system involving significant civil centres and a hospital. Moving from the need of a new heat and power station for the local hospital due to the construction of new pavilions, the opportunity of involving other centres in the neighbourhood in a distributed cogeneration system is analysed, increasing system complexity step by step. Smaller cogeneration units tailored to hospital needs are rewarding ventures with relatively low risks but, in a country whose traditional power generation systems heavily rely on fossil fuels and where energy policy and market conditions can make it profitable to sell surplus power, district heating systems foster the installation of larger cogenerators and lead thereby to higher profits and to better performance as for primary energy savings and greenhouse gases emission reduction. Copyright © 2006 John Wiley & Sons, Ltd.     

The origin of the band at 1462 cm−1 generally appearing upon desorption of pyridine from acidic solids. Steps towards a more comprehensive understanding

The pyridine adsorption-desorption method, followed by IR spectroscopy, is generally applied for acidity determination of solid catalysts. A peculiar band at 1462 cm^–1 was observed by several authors upon pyridine desorption at higher temperatures and was interpreted in various ways. A new complex between Lewis framework acid sites and pyridine is proposed and several evidences are reported.     

Confocal Blood Flow Videomicroscopy of Thrombus Formation over Human Arteries and Local Targeting of P2X7

Atherothrombosis exposes vascular components to blood. Currently, new antithrombotic therapies are emerging. Herein we investigated thrombogenesis of human arteries with/without atherosclerosis, and the interaction of coagulation and vascular components, we and explored the anti-thrombogenic efficacy of blockade of the P2X purinoceptor 7 (P2X7). A confocal blood flow videomicroscopy system was performed on cryosections of internal mammary artery (IMA) or carotid plaque (CPL) determining/localizing platelets and fibrin. Blood from healthy donors elicited thrombi over arterial layers. Confocal microscopy associated thrombus with tissue presence of collagen type I, laminin, fibrin(ogen) and tissue factor (TF). The addition of antibodies blocking TF (aTF) or factor XI (aFXI) to blood significantly reduced fibrin deposition, variable platelet aggregation and aTF + aFXI almost abolished thrombus formation, showing synergy between coagulation pathways. A scarce effect of aTF over sub-endothelial regions, more abundant in tissue TF and bundles of laminin and collagen type I than deep intima, may suggest tissue thrombogenicity as molecular structure-related. Consistently with TF-related vascular function and expression of P2X7, the sections from CPL but not IMA tissue cultures pre-treated with the P2X7 antagonist A740003 demonstrated poor thrombogenesis in flow experiments. These data hint to local targeting studies on P2X7 modulation for atherothrombosis prevention/therapy.     

Selective Complexation and Membrane Transport of Guanidinium Salts by Calix[6]arene Amides

The p-tert-butylcalix[6]arene hexamide 2 and syn-1,3,5–trimethoxy-2,4,6-triamide 4 were synthesized by reaction of α-chloro-N,N-diethylacetamide and the corresponding calix[6]arenes 1 and 3 , respectively. ¹H NMR spectroscopy shows that 2 is a mixture of different conformations whereas 4 is fixed in a cone conformation. Extraction experiments, (S-L) and (H₂O–CDCl₃) with picrate salts, indicate that 2 complexes both alkali metal (1:2 complex) and guanidinium salts (1:1 complex) but 4 complexes only guanidinium (1:1 complex). Incorporated in supported liquid membranes (Accurel^® / o-nitrophenyl n-octyl ether) the calixarenes 2 and 4 transport guanidinium salts. The hexamide 2 is a more efficient carrier of guanidinium but the syn-1,3,5-trimethoxy-2,4,6-triamide 4 is much more selective. Both 2 and 4 are sufficiently lipophilic to give membranes that are stable over longer periods (weeks).     

An interface finite element for the simulation of localized membrane-bending deformation in shells

The folding of thin shells around localized lines occurs in several situations of engineering interest, such as in buckling induced deformation, as the consequence of crash, in industrial processes like metal forming, in the deployment of folded membranes, in packaging related processes. In this paper an interface element, allowing for displacement and rotation discontinuities, to be placed between two adjacent 4-node Mindlin–Reissner shell finite elements, is developed for a computationally effective simulation of this type of localized deformation. The large displacement and rotation kinematics of the interface element is discussed, arriving at a rigid-rotation free element tangent stiffness matrix. An adaptive dynamic relaxation scheme is proposed for the evolutionary analysis of the quasi-static structural response. To test the element formulation, a simple coupled membrane-bending elastoplastic behavior is assumed. The element is used for the simulation of few examples taken from the literature, where the structural response is characterized by the formation of plastic hinges, exhibiting good accuracy and computational effectiveness.