Premessa

L'edizione di questo libro nasce dall'esigenza di precisare e divulgare gli esiti del dibattito che, in occasione del quarto centenario dalla fondazione dei Quattro Canti, ha coinvolto studiosi italiani e stranieri. Il volume raccoglie i contributi elaborati in quella occasione con l'intento di aggiornare e approfondire il panorama delle conoscenze, in relazione alle diverse tematiche implicate in una vicenda pressoché unica

BIAXIAL CURVATURE AND DUCTILITY CAPACITY OF RC COLUMN BASE CROSS SECTIONS

The deformation performance of the base cross sections of reinforced concrete buildings is fundamental when large seismic events occur allowing the structure to have large excursions in nonlinear field and guaranteeing an overall ductile behaviour. It is well known that the axial force acting on columns significantly reduces the curvature capacity of the sections and for this reason the technical codes give design criteria stating a limitation in order to preserve the displacement capacity. It is also recognized that when biaxial bending occur the cross section undergo a loss in strength capacity. Starting the study of from Bresler (1960), which provided suitable expression to predict 3D limit interaction surfaces, several numerical and analytical models were developed to take into account the biaxial interaction in strength. Simultaneously it is noteworthy to point out that the presence of biaxial bending also influences the deformation capacity of sections causing in most of the cases a relevant loss of the curvature and ductility available with respect to the one owned along the principal axes. This important issue is not faced by technical codes and not exhaustively treated in scientific literature as it was done for strength. Moreover nonlinear structural models based on lumped plasticity do not take into account these interaction aspects when defining plastic hinge properties in terms of curvature capacity. The paper presents a numerical study in which the deformation capacity of RC cross sections subjected to axial load and biaxial bending is investigated by means of a fiber discretization. A procedure for the numerical definition of biaxial domains of ultimate curvature, yielding curvature and curvature ductility is provided and the sensitivity of the biaxial deformation performance to some geometrical and mechanical parameters (aspect ratio, concrete strength and confinement efficacy) is discussed.The deformation performance of the base cross sections of reinforced concrete buildings is fundamental when large seismic events occur allowing the structure to have large excursions in nonlinear field and guaranteeing an overall ductile behaviour. It is well known that the axial force acting on columns significantly reduces the curvature capacity of the sections and for this reason the technical codes give design criteria stating a limitation in order to preserve the displacement capacity. It is also recognized that when biaxial bending occur the cross section undergo a loss in strength capacity. Starting the study of from Bresler (1960), which provided suitable expression to predict 3D limit interaction surfaces, several numerical and analytical models were developed to take into account the biaxial interaction in strength. Simultaneously it is noteworthy to point out that the presence of biaxial bending also influences the deformation capacity of sections causing in most of the cases a relevant loss of the curvature and ductility available with respect to the one owned along the principal axes. This important issue is not faced by technical codes and not exhaustively treated in scientific literature as it was done for strength. Moreover nonlinear structural models based on lumped plasticity do not take into account these interaction aspects when defining plastic hinge properties in terms of curvature capacity. The paper presents a numerical study in which the deformation capacity of RC cross sections subjected to axial load and biaxial bending is investigated by means of a fiber discretization. A procedure for the numerical definition of biaxial domains of ultimate curvature, yielding curvature and curvature ductility is provided and the sensitivity of the biaxial deformation performance to some geometrical and mechanical parameters (aspect ratio, concrete strength and confinement efficacy) is discussed

Definition of seismic vulnerability maps for civil protection systems: The case of lampedusa Island

The opportunity to locate and quantify the major criticalities associated to natural catastrophic events on a territory allows to plan adequate strategies and interventions by civil protection bodies involved in local and international emergencies. Seismic risk depends, most of all, on the vulnerability of buildings belonging to the urban areas. For this reason, the definition, by a deep analysis of the territory, of instruments identifying and locating vulnerability, largely favours the activities of institutions appointed to safeguard the safety of citizens. This paper proposes a procedure for the definition of vulnerability maps in terms of vulnerability indexes and critical peak ground accelerations for mid-small urban centres belonging to Mediterranean areas. The procedure, tested on the city centre of the Island of Lampedusa, is based on a preliminary historical investigation of the urban area and of the main formal and technological features of buildings involved. Moreover, the vulnerability of the constructions is evaluated by fast assessment methods (filling of evaluation forms). The vulnerability model, allowing the definition of the fragility curves, is calibrated on the basis of the results of an identification process of prototype buildings, selected to be adequately representative. Their characterizations have been provided using the results of an experimental dynamic investigation to develop high representative numerical model. Critical PGA values have been determined by pushover analyses. The results presented provided an unambiguous representation of the major criticalities with respect to seismic vulnerability and risk, of the city centre of the island, being a suitable tool for planning and handling of emergencies

Anti-inflammatory and antioxidant effects of muscarinic acetylcholine receptor (mAChR) activation in the rat hippocampus

Recently we found that acute treatment with Oxotremorine (Oxo), a non-selective mAChRs agonist, up-regulates heat shock proteins and activates their transcription factor heat shock factor 1 in the rat hippocampus. Here we aimed to investigate: a) if acute treatment with Oxo may regulate pro-inflammatory or anti-inflammatory cytokines and oxidative stress in the rat hippocampus; b) if chronic restraint stress (CRS) induces inflammatory or oxidative alterations in the hippocampus and whether such alterations may be affected by chronic treatment with Oxo. In the acute experiment, rats were injected with single dose of Oxo (0.4 mg/kg) and sacrificed at 24 h, 48 h and 72 h. In the CRS experiment, the rats were exposed for 21 days to the CRS and then were treated with Oxo (0.2 mg/kg) for further 10 days. The acute Oxo treatment showed an ability to significantly reduce reactive oxygen species (ROS), singlet oxygen (1O2), pro-inflammatory cytokines levels (IL-1β and IL-6) and phosphorylated NF-κB-p65. Acute Oxo treatment also increased superoxide dismutase (SOD)-2 protein levels and stimulated SOD activity. No differences were detected in the anti-inflammatory cytokine levels, including IL-10 and TGF-β1. In the group of rats exposed to the CRS were found increased hippocampal IL-1β and IL-6 levels, together with a reduction of SOD activity level. These changes produced by CRS were counteracted by chronic Oxo treatment. In contrast, the upregulation of ROS and 1O2 levels in the CRS group was not counteracted by chronic Oxo treatment. The results revealed a hippocampal anti-inflammatory and antioxidant effect of Oxo treatment in both basal conditions and anti-inflammatory in the CRS rat model

Giorgio Vasari a Palazzo Abatellis. Percorsi del Rinascimento in Sicilia

La mostra si inserisce nell'ambito delle celebrazioni per i 500 anni della nascita di Giorgio Vasari (1511-2011), ricorrenza che, nel corso dell'anno, \ue8 stata oggetto di numerosi eventi culturali italiani e internazionali. L'iniziativa nasce dalla collaborazione tra la Biblioteca Centrale della Regione siciliana "A. Bombace", la sezione "Sfera" del Dipartimento di Architettura dell'Universit\ue0 degli Studi di Palermo, e la Galleria Interdisciplinare Regionale della Sicilia, istituzione che custodisce, nella prestigiosa sede di Palazzo Abatellis, due grandi dipinti su tavola di Vasari, costituenti le ricurve parti laterali del trittico della "Caduta della manna" realizzato nel 1545 per il refettorio di Santa Maria di Monteoliveto a Napoli. Le lunette vasariane, esposte in modo permanente dal 2009 ma ancora quasi del tutto sconosciute a studiosi e pubblico, per l'occasione sono state ricollocate secondo gli originali rapporti dimensionali con il perduto quadro centrale e poste in relazione con il disegno preparatorio dello stesso Vasari, oggi custodito presso l'Ecole nationale superieure des beaux-arts di Parigi. Il percorso analitico, che si \ue8 avvalso anche del prezioso contributo di Claudia Conforti, tra le pi\uf9 autorevoli studiose dell'artista aretino, e delle competenze tecniche dell'Associazione culturale LapiS, \ue8 stato svolto secondo tre tematiche connesse alla poliedrica attivit\ue0 vasariana e al suo contesto culturale: la pittura e l'arte del disegno, la produzione letteraria, l'architettura. Al patrimonio pittorico e grafico della Galleria, riconducibile a quella che lo stesso Vasari definisce \uabmaniera moderna\ubb, sono stati quindi associati preziosi volumi a stampa, a partire dalla rara edizione del 1568 delle "Vite de' pi\uf9 eccellenti architetti, pittori e scultori italiani", e pannelli illustrativi riferiti a opere siciliane di architetti e scultori citati nelle "Vite" vasariane, costituenti alcune pregnanti testimonianze del Rinascimento in Sicili

Molecular Epidemiology of HIV-1 Transmission in a Cohort of HIV-1 Concordant Heterosexual Couples from Dakar, Senegal

BACKGROUND: A large number of HIV-1 infections in Africa occur in married couples. The predominant direction of intracouple transmission and the principal external origins of infection remain important issues of debate. METHODS: We investigated HIV-1 transmission in 46 HIV-1 concordant positive couples from Dakar, Senegal. Intracouple transmission was confirmed by maximum-likelihood phylogenetic analysis and pairwise distance comparisons of HIV-1 env gp41 sequences from both partners. Standardized interview data were used to deduce the direction as well as the external sources of the intracouple transmissions. RESULTS: Conservative molecular analyses showed linked viruses in 34 (74%) couples, unlinked viruses in 6 (13%) couples, and indeterminate results for 6 (13%) couples. The interview data corresponded completely with the molecular analyses: all linked couples reported internal transmission and all unlinked couples reported external sources of infection. The majority of linked couples (93%) reported the husband as internal source of infection. These husbands most frequently (82%) reported an occasional sexual relationship as external source of infection. Pairwise comparisons of the CD4 count, antiretroviral therapy status, and the proportion of gp41 ambiguous base pairs within transmission pairs correlated with the reported order of infection events. CONCLUSIONS: In this suburban Senegalese population, a majority of HIV-1 concordant couples showed linked HIV-1 transmission with the husband as likely index partner. Our data emphasize the risk of married women for acquiring HIV-1 as a result of the occasional sexual relationships of their husbands

Newly Developed Mg2+–Selective Fluorescent Probe Enables Visualization of Mg2+ Dynamics in Mitochondria

Mg2+ plays important roles in numerous cellular functions. Mitochondria take part in intracellular Mg2+ regulation and the Mg2+ concentration in mitochondria affects the synthesis of ATP. However, there are few methods to observe Mg2+ in mitochondria in intact cells. Here, we have developed a novel Mg2+–selective fluorescent probe, KMG-301, that is functional in mitochondria. This probe changes its fluorescence properties solely depending on the Mg2+ concentration in mitochondria under physiologically normal conditions. Simultaneous measurements using this probe together with a probe for cytosolic Mg2+, KMG-104, enabled us to compare the dynamics of Mg2+ in the cytosol and in mitochondria. With this method, carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP)–induced Mg2+ mobilization from mitochondria to the cytosol was visualized. Although a FCCP–induced decrease in the Mg2+ concentration in mitochondria and an increase in the cytosol were observed both in differentiated PC12 cells and in hippocampal neurons, the time-courses of concentration changes varied with cell type. Moreover, the relationship between mitochondrial Mg2+ and Parkinson's disease was analyzed in a cellular model of Parkinson's disease by using the 1-methyl-4-phenylpyridinium ion (MPP+). A gradual decrease in the Mg2+ concentration in mitochondria was observed in response to MPP+ in differentiated PC12 cells. These results indicate that KMG-301 is useful for investigating Mg2+ dynamics in mitochondria. All animal procedures to obtain neurons from Wistar rats were approved by the ethical committee of Keio University (permit number is 09106-(1))