Simplified closed-form solution for the determination of the moment-curvature response of a circular RC section

A seismic vulnerability analysis of a multi-span simply supported bridge is often based on the seismic response of the most critical pier. This response is influenced by different collapse modes (flexural, shear, second order effects, lap-splice of longitudinal bars or their buckling). Among these the flexural behaviour is important and it's known if the equivalent plastic hinge length and the Moment-Curvature law of the fixed end are given. This paper provides a closed-form dimensionless solution to obtain a 5 point Moment-Curvature diagram for circular RC section. The solution is based only on three parameters: dimensionless axial force, mechanical percentage of longitudinal reinforcement, geometrical percentage of transversal reinforcement. A numerical example is presented to test the solution comparing it with a FEM analysis

Formulazione semplificata per il calcolo in forma chiusa del diagramma Momento-Curvatura di una sezione circolare cava in CA (in Italian)

Per un’analisi di vulnerabilità di un ponte a travata è possibile assumere che la curva di capacità della struttura sia approssimabile con la curva di capacità della pila critica. Il comportamento della pila critica può essere, in generale, influenzato da vari meccanismi quali la flessione, il taglio, gli effetti del second’ordine, lo sfilamento delle barre longitudinali o la loro instabilizzazione. Il comportamento flessionale è noto se si conosce il diagramma MomentoCurvatura della sezione d’incastro e la lunghezza di cerniera plastica. Considerando che gli altri meccanismi possono essere valutati con formulazioni approssimate l’aspetto chiave del problema è il diagramma MomentoCurvatura. Dopo aver valutato la sezione circolare piena in lavori precedenti, nella presente memoria si propone una procedura per valutare il diagramma Momento-Curvatura di una sezione circolare cava in C.A. definendo la posizione di alcuni suoi punti caratteristici. Per ognuno di questi si propone una soluzione adimensionale in forma chiusa che dipende da quattro parametri anch’essi adimensionali: rapporto tra raggio del foro e raggio esterno, rapporto di sforzo normale, rapporto meccanico di armatura longitudinale, rapporto volumetrico di staffatura. L’idea di base è quella di avere buone indicazioni sulle prestazioni dei materiali (snervamento, salto del copriferro, collasso, etc) basandosi su pochi parametri di input

Definizione della nicchia staminale nella colecisti normale e patologica. Isolamento, caratterizzazione,differenziazione, dimostrazione dell’abilità delle cellule staminali isolate di rigenerare il tessuto epatico in modelli sperimentali di danno epatico ed efficace criopreservazione.

All'interno delle ghiandole peribiliari dell’albero biliare umano adulto sono state evidenziate cellule staminali che esprimono marcatori di endoderma primitivo. Le stesse cellule hanno dimostrato di possedere la capacità di differenziarsi in vitro e in vivo in epatociti e colangiociti maturi e insule pancreatiche funzionanti. Nulla è finora conosciuto sull’esistenza di cellule staminali/progenitrici nella colecisti umana. Gli obiettivi dello studio sono stati la caratterizzazione della nicchia staminale della colecisti umana, la possibilità di isolare cellule staminali di origine endodermica dalla colecisti umana normale o patologica e la definizione delle condizioni ideali per la loro criopreservazione. N° 19 colecisti sono state ottenute da donatori cadavere adulti esenti da patologie epato-bilio-pancreatiche attraverso il Consorzio Regionale Trapianti d’Organo del Lazio (Italia). N°14 colecisti patologiche sono state prelevate da pazienti affetti da litiasi sintomatica o da pazienti affetti da litiasi asintomatica sottoposti ad exeresi chirurgica in corso di chirurgia bariatrica. Il tessuto colecistico è stato digerito con collagenasi e DNAsi e la sospensione cellulare è stata sottoposta ad immunoselezione per un marcatore di cellule staminali di origine endodermica (EpCAM-Epithelial Cell Adhesion Molecule). Le colture cellulari ottenute sono state mantenute in coltura in Kubota’s Medium (KM), un mezzo di coltura privo di fattori di crescita sviluppato per l’espansione di cellule staminali epatiche in vitro. La valutazione della multi potenzialità è stata effettuata in vitro utilizzando mezzi di coltura a base di KM arricchiti con fattori di crescita e di induzione specifici per i diversi destini maturi di derivazione endodermica (epatociti, colangiociti, isole pancreatiche). Risultati: La colecisti non contiene ghiandole peribiliari, tuttavia, all’interno delle cripte della mucosa colecisti umana sono state individuate popolazione cellulari che esprimono marcatori di cellule progenitrici bilio-pancreatiche (SOX17, PDX1, EpCAM) e di cellule di endoderma primitivo (CXCR4). I risultati dell’analisi morfologica e fenotipica della colecisti patologica sono paragonabili a quelli ottenuti nelle colecisti normali. Cellule immunoselezionate per EpCAM dalla colecisti umana si espandono clonogenicamente su plastica e in un mezzo privo di siero adattato per progenitori endodermici (KM). Cellule isolate dalle colonie, dopo un mese di coltura in KM, sono state trasferite in tre distinti medium bidimensionali ed hanno dato origine a colonie cellulari con caratteristiche epatocitarie, colangiocitarie e di insule pancreatiche funzionanti. Abbiamo condotto studi pre-clinici in modelli sperimentali di epatopatie (topi immunodeficenti SCID) trattati per 7 settimane con trettracloruro di carbonio (CCL4) attraverso l’utilizzo di cellule staminali/progenitrici della colecisti umana (human gallbladder stem/progenitor cells, hGSCs). Al termine gli animali sono stati sacrificati e dopo aver valutato l’attecchimento, la proliferazione, la differenziazione in vivo, abbiamo dimostrato, analizzando i test funzionali sul siero dei topi sacrificati, che solo i topi trattati con le hGSCs mostrano un miglioramento degli indici sierologici di funzionalità epatica. Al fine di individuare la migliore strategia per la criopreservazione delle hGSCs, è stato condotto uno studio in cui sono state analizzate soluzioni criopreservanti con diversa composizione. E’ stata identificata una metodica efficace per il congelamento di cellule staminali/progenitrici, comprese le hGSCs. Le hGSCs sono facilmente isolabili da tessuti umani di donatori di ogni età ed immediatamente utilizzabili per la creazione di banche di cellule staminali/progenitrici che possono essere conservate e utilizzate in pazienti con grave e letale compromissione della funzione del fegato, i quali spesso non sopravvivono all’attesa del trapianto di fegato

Non-linear analysis of RC masonry-infilled frames using the SLaMA method: part 1—mechanical interpretation of the infill/frame interaction and formulation of the procedure

The simple lateral mechanism analysis (SLaMA) is an analytical method to assess the force–displacement capacity curve of Reinforced Concrete (RC) structures composed of frames, cantilever walls or dual wall/frame systems. The current version of the method was proposed in the 2017 New Zealand guidelines for the seismic assessment (NZSEE in New Zealand Society for Earthquake Engineering, the seismic assessment of existing buildings—technical guidelines for engineering assessments, Wellington, 2017). Regarding frame structures, the possible influence of infill walls is currently considered locally with checks on the RC members. However, it is universally known that infills have a major effect on the global capacity curve of the frame. In this paper, a comprehensive SLaMA method for infilled frames is proposed, which allows considering the influence of the infills on the global force–displacement curve without any numerical algorithm. The extended SLaMA method is herein formalised and it is validated in a companion paper (part 2) through an extensive parametric analysis. The extended SLaMA is based on the possibility to separately calculate the base shear contributions of the frame and the infills, in turn based on global equilibrium considerations. Such considerations also allow defining a novel procedure to post-process the results of pushover or time-history analyses where infills are modelled as diagonal struts, or to interpret experimental tests. This allows, within a single numerical analysis, to decouple the frame and infills contributions to the base-shear capacity. The decoupling procedure is herein demonstrated for an ideal two-storey, one-bay masonry-infilled frame with different infills configurations

Echocardiographic evaluation of left ventricular outflow tract obstruction in complete transposition of the great arteries

Subpulmonic stenosis in complete d-transposition of the great arteries (d-TGA) is a frequently associated malformation, the precise diagnosis of which is essential for optimal medical and surgical treatment. Sixteen patients with d-TGA and subpulmonic stenosis have been studied by M-mode and two-dimensional (2DE) echocardiography and cardiac catheterization. Dynamic obstruction was found in six patients and fixed stenosis in 10. Systolic anterior motion of the mitral valve without fixed obstruction of the left ventricular outflow tract (LVOT) was present in patients with dynamic stenosis. Measurements of left ventricular end-diastolic posterior wall thickness to minor semiaxis ratio correlated well (p < 0.001) with the pressure gradient across the LVOT. Various types of anatomic fixed obstruction are described. M-mode echocardiography provides assessment of dynamic obstruction but does not allow quantitative evaluation of the length of the narrowed segment. The latter can be achieved by 2DE, which offers improved definition of different anatomic types

I fragili confini del territorio: a proposito dell’efficacia extraterritoriale dei diritti

Il contributo analizza i casi giurisdizionali di maggiore rilievo in tema di efficacia extraterritoriale dei diritti, soffermandosi sugli aspetti più critici e sottolineandone i profili di maggiore interesse. Copiosa è la giurisprudenza delle Corti Supreme degli Stati Uniti e del Canada, le quali hanno affrontato il problema con particolare riferimento al privilegio dell’habeas corpus e al giusto processo. Alcune recenti pronunce della Corte di giustizia UE e della Corte europea dei diritti dell’uomo mostrano invece come le attività di sorveglianza elettronica e di intelligence sharing pongano in una nuova luce la questione dell’efficacia territoriale delle Carte dei diritti. Un’ultima riflessione la impone una recente sentenza del Tribunale costituzionale federale tedesco, sempre in materia di sorveglianza elettronica, con cui è stato affermato – per la prima volta – che le autorità pubbliche sono vincolate al rispetto dei diritti sanciti in Costituzione anche quando agiscono all’estero.The contribution analyses the most important jurisdictional cases on the extraterritorial effectiveness of rights, focusing on the most critical aspects and highlighting the most interesting profiles. The case law of the Supreme Courts of the United States and Canada is substantial, and they have addressed the issue with particular reference to the habeas corpus privilege and due process. On the other hand, some recent rulings of the EU Court of Justice and the European Court of Human Rights show how electronic supervision and intelligence sharing activities shed new light on the question of the territorial effectiveness of the Charters of Rights. A last reflection is required by a recent ruling of the German Federal Constitutional Court, also on the subject of electronic supervision, which affirmed - for the first time - that public authorities are bound to respect the rights enshrined in the Constitution even when they act abroad

Echocardiographic assessment of congenital mitral stenosis.

To assess the severity and precise anatomy of congenital mitral stenosis (MS), 17 patients with congenital left ventricular inflow obstruction were studied by M-mode and two-dimensional echocardiography (2DE) and by cardiac catheterization. In six patients MS was an isolated lesion and in 11 it was combined with other cardiovascular malformations. The diagnosis was confirmed at operation or autopsy in 15 patients. Twenty normal subjects of the same age and sex were selected as controls. M-mode amplitude and speed of diastolic closure (E-F slope) of the anterior mitral valve leaflet were determined in all patients. Mitral valve areas were traced after careful short-axis 2DE scans in 15 patients. Supravalvar, valvar, or subvalvar obstruction was evaluated in patients with surgical or autopsy documentation. Analysis of M-mode echocardiograms showed a reduction of E-F slope in all patients compared to normal control subjects but a poor correlation between E-F slope and hemodynamic data (mitral valve areas or pressure gradients). Diastolic fluttering of either or both mitral valve leaflets was found in 12 patients. It is concluded that M-mode echocardiography may be useful for qualitative assessment of congenital MS, even in the presence of associated heart defects, but less useful in evaluating its severity. Analysis of 2DE revealed good correlation between mitral valve areas as calculated with 2DE and with the Gorlin formula at cardiac catheterization, despite the complexity of the congenital mitral lesion. Anatomic varieties of congenital left ventricular inflow obstruction, such as stenosing supravalvar mitral ring or parachute deformity of the mitral valve, were recognized at 2DE.(ABSTRACT TRUNCATED AT 250 WORDS

Cloud Capacity Spectrum Method: Accounting for record-to-record variability in fragility analysis using nonlinear static procedures

This paper investigates a number of computational issues related to the use of nonlinear static procedures in fragility analysis of structures. Such approaches can be used to complement nonlinear dynamic procedures, reducing the computational and modelling effort. Specifically, this study assesses the performance of the Capacity Spectrum Method (CSM) with real (i.e. recorded) ground motions (as opposed to code-based conventional spectra) to explicitly account for record-to-record variability in fragility analysis. The study focuses on single-degree-of-freedom systems, providing a basis for future multi-degree-of-freedom system applications. A case-study database of 2160 inelastic oscillators is defined through parametric backbones with different elastic periods, (yield) base shear coefficients, values of the ductility capacity, hardening ratios, residual strength values and hysteresis rules. These case studies are analysed using 100 real ground motions. An efficient algorithm to perform the CSM with real spectra is proposed, combined with a cloud-based approach (Cloud-CSM) to derive fragility relationships. Simple criteria to solve the issue of multiple CSM solutions (i.e. two or more points on the backbone satisfying the CSM procedure) are proposed and tested. It is demonstrated that the performance point selection can be carried out based on a particularly efficient intensity measure detected via optimal intensity measure analysis. The effectiveness of the proposed Cloud-CSM in fragility analysis is discussed through extensive comparisons with nonlinear time-history analyses, the code-based N2 method, and a simple method involving an intensity measure as a direct proxy for the performance displacement. The Cloud-CSM provides errors lower than ±20% in predicting the median of the fragility curves in most of the analysed cases and outperforms the other considered methodologies in calculating the fragility dispersion

Experimental Bayesian Quantum Phase Estimation on a Silicon Photonic Chip

Quantum phase estimation is a fundamental subroutine in many quantum algorithms, including Shor's factorization algorithm and quantum simulation. However, so far results have cast doubt on its practicability for near-term, non-fault tolerant, quantum devices. Here we report experimental results demonstrating that this intuition need not be true. We implement a recently proposed adaptive Bayesian approach to quantum phase estimation and use it to simulate molecular energies on a Silicon quantum photonic device. The approach is verified to be well suited for pre-threshold quantum processors by investigating its superior robustness to noise and decoherence compared to the iterative phase estimation algorithm. This shows a promising route to unlock the power of quantum phase estimation much sooner than previously believed

Simplified polynomial formulation for the calculation of the Moment-Curvature diagram of RC rectangular sections

The seismic response of multi-span RC bridges is often based on the response of the piers, provided that deck, bearings and foundations remain elastic. The seismic response of a RC bridge pier is influenced, in general, by different mechanisms (i.e. flexure, shear, lap-splice or buckling of the longitudinal reinforcement bars, second order effects). For mechanisms different from the flexural one, simplified formulations are available in literature. On the other hand, the flexural behaviour of the pier can be characterised by means of equivalent plastic hinge length and Moment-Curvature diagram of the base section, usually carried out with a computer software. In this paper, it is proposed a simplified analytical solution to obtain the Moment-Curvature relationship for rectangular RC sections, in both principal axes. The solution is based on adjusted polynomials, fitted against a database of 800 numerical Moment-Curvature analyses of rectangular RC sections. The proposed polynomials allow to define the cross-section capacity curve through the position of 6 characteristic points and they are based on 4 input parameters: depth-towidth ratio of the cross-section, axial force ratio, longitudinal reinforcement ratio, transversal reinforcement ratio. The solution is tested through the application to a RC rectangular section case study and comparison of the resulting capacity curves to the outcome of refined numerical Moment-Curvature analyses. The results show that the proposed analytical solution is a reliable method to characterise the flexural response of RC rectangular cross-sections