Gli effetti dell’introduzione della nuova mappa di pericolosità sulla valutazione del rischio sismico in Italia.

L’introduzione di una versione aggiornata della mappa di pericolosità sismica, definita per diversi periodi di ritorno e per svariati valori di ordinate spettrali, porta inevitabilmente a dei cambiamenti sul livello di rischio sismico del costruito italiano. Poiché la relazione tra domanda e capacità non è lineare per tutto il range di periodi di vibrazione strutturale, è necessario valutare il cambiamento del livello di rischio sismico calcolando esplicitamente la vulnerabilità sismica di strutture esistenti con diversi periodi di vibrazione, per diversi stati limite e considerando sia la nuova che la precedente definizione di pericolosità. Nel presente lavoro è stato eseguito un primo studio degli effetti che l’introduzione di mappe aggiornate della pericolosità sismica potrebbe avere sulla valutazione dei livelli di rischio sismico nel territorio italiano. Le caratteristiche generali del costruito sono state ricavate dai dati del 14° Censimento Generale della Popolazione e delle Abitazioni (ISTAT 2001), mentre una procedura probabilistica di valutazione sismica per edifici esistenti a scala urbana è stata impiegata per stimare la capacità. Sono stati considerati tutti i tre stati limite prescritti dall’Ordinanza (danno lieve, danno severo, collasso) in corrispondenza dei rispettivi valori di domanda, così come il cambiamento delle forme spettrali in funzione della localizzazione e del periodo di ritorno. I risultati dimostrano che la nuova mappa di pericolosità sismica porta a dei livelli di rischio sismico più realistici e meno allarmanti, rendendo leggermente meno gravoso, anche se non privo di problematiche, il panorama attuale di rischio in Italia

Low- and intermediate-temperature ammonia/hydrogen oxidation in a flow reactor: Experiments and a wide-range kinetic modeling

Understanding the chemistry behind the oxidation of ammonia/hydrogen mixtures is crucial for ensuring the flexible use of such mixtures in several applications, related to propulsion systems and power generation. In this work, the oxidation of ammonia/hydrogen blends was investigated through an experimental and kinetic-modeling study, where the low- and intermediate-temperature conditions were considered. An experimental campaign was performed in a flow reactor, at stoichiometric conditions and near-atmospheric pressure (126.7 kPa). The mole fraction of fuels, oxidizer and final products was measured. At the same time, a comprehensive kinetic model was set up, following a modular and hierarchical approach, and implementing the recently-available elementary rates. Such a model was used to interpret the experimental results, and to extend the analysis to literature data, covering several oxidation features. The reactivity boost provided by H2 addition was found to be approximately linear with its mole fraction in both flow- and jet-stirred-reactor conditions (except for the smallest H2 amounts in the flow reactor), in contrast with the more-than-linear increase in the laminar flame speed. The key role of HO2 in regulating fuel conversion and autoignition at low temperature was confirmed for binary mixtures, with H2NO being the bottleneck to the low-temperature oxidation of NH3-rich blends. On the other hand, the nitrogen fate was found to be mostly regulated by NHx + NO propagation and termination channels

Life events, anxious depression and personality: a prospective and genetic study.

Background: The association between life events and anxious depression might be due to causality or to gene-environment correlation. We examined unidirectional and reciprocal causality and a gene-environment correlation model, in which genes that influence the vulnerability for anxious depression also increase the risk of exposure to life events. The effect of genes that influence environmental exposure might be mediated through personality and we therefore also examined the association between life events and personality (neuroticism and extraversion). Method: Information on life events, anxious depression, neuroticism and extraversion was collected in 5782 monozygotic (MZ) and dizygotic (DZ) twins who participated in a longitudinal survey study of the Netherlands Twin Register. To examine causality, data were analysed longitudinally. To examine gene-environment correlation, the co-twin control method was used. Results: Anxious depression and, to a lesser extent, neuroticism scores increased after exposure to life events. Anxious depression and neuroticism also predicted the experience of life events. Prospectively, extraversion was not associated with life events. Anxious depression, neuroticism and extraversion scores did not differ between the non-exposed subjects of MZ and DZ twin pairs and unrelated subjects discordant for life events. Conclusions: Our findings suggest that reciprocal causation explains the relationship between life events and anxious depression and between life events and neuroticism. Extraversion is not related to life events. No evidence was found for gene-environment correlation, i.e. the genes that influence anxious depression, neuroticism or extraversion do not overlap with the genes that increase the risk of exposure to life events

Fully-resolved simulations of coal particle combustion using a detailed multi-step approach for heterogeneous kinetics

Fully-resolved simulations of the heating, ignition, volatile flame combustion and char conversion of single coal particles in convective gas environments are conducted and compared to experimental data (Molina and Shaddix, 2007). This work extends a previous computational study (Tufano et al., 2016) by adding a significant level of model fidelity and generality, in particular with regard to the particle interior description and hetero- geneous kinetics. The model considers the elemental analysis of the given coal and interpolates its properties by linear superposition of a set of reference coals. The improved model description alleviates previously made assumptions of single-step pyrolysis, fixed volatile composition and simplified particle interior properties, and it allows for the consideration of char conversion. The results show that the burning behavior is affected by the oxygen concentration, i.e. for enhanced oxygen levels ignition occurs in a single step, whereas decreasing the oxygen content leads to a two-stage ignition process. Char conversion becomes dominant once the volatiles have been depleted, but also causes noticeable deviations of temperature, released mass, and overall particle con- version during devolatilization already, indicating an overlap of the two stages of coal conversion which are usually considered to be consecutive. The complex pyrolysis model leads to non-monotonous profiles of the combustion quantities which introduce a minor dependency of the ignition delay time $τ_{ign}$ on its definition. Regardless of the chosen extraction method, the simulations capture the measured values of $τ_{ign}$ very well

Ophthalmoplegia due to Miller Fisher syndrome in a patient with myasthenia gravis

Here, we describe a 79-year-old man, admitted to our unit for worsening diplopia and fatigue, started a few weeks after an episode of bronchitis and flu vaccination. Past medical history includes myasthenia gravis (MG), well-controlled by Pyridostigmine, Azathioprine, and Prednisone. During the first days, the patient developed progressive ocular movement abnormalities up to complete external ophthalmoplegia, severe limb and gait ataxia, and mild dysarthria. Deep tendon reflexes were absent in lower limbs. Since not all the symptoms were explainable with the previous diagnosis of myasthenia gravis, other etiologies were investigated. Brain MRI and cerebrospinal fluid analysis were normal. Electromyography showed a pattern of predominantly sensory multiple radiculoneuritis. Suspecting Miller Fisher syndrome (MFS), the patient was treated with plasmapheresis with subsequent clinical improvement. Antibodies against GQ1b turned out to be positive. MFS is an immune-mediated neuropathy presenting with ophthalmoplegia, ataxia, and areflexia. Even if only a few cases of MFS overlapping with MG have been described so far, the coexistence of two different autoimmune disorders can occur. It is always important to evaluate possible differential diagnosis even in case of known compatible diseases, especially when some clinical features seem atypical

Topologically non-trivial metal-organic assemblies inhibit \u3b22-microglobulin amyloidogenesis

Inhibiting amyloid aggregation through high-turnover dynamic interactions could be an efficient strategy that is already used by small heat-shock proteins in different biological contexts. We report the interactions of three topologically non-trivial, zinc-templated metal-organic assemblies, a [2]catenane, a trefoil knot (TK), and Borromean rings, with two \u3b22-microglobulin (\u3b22m) variants responsible for amyloidotic pathologies. Fast exchange and similar patterns of preferred contact surface are observed by NMR, consistent with molecular dynamics simulations. In vitro fibrillation is inhibited by each complex, whereas the zinc-free TK induces protein aggregation and does not inhibit fibrillogenesis. The metal coordination imposes structural rigidity that determines the contact area on the \u3b22m surface depending on the complex dimensions, ensuring in vitro prevention of fibrillogenesis. Administration of TK, the best protein-contacting species, to a disease-model organism, namely a Caenorhabditis elegans mutant expressing the D76N \u3b22m variant, confirms the bioactivity potential of the knot topology and suggests new developments

C. elegans expressing D76N β2-microglobulin: a model for in vivo screening of drug candidates targeting amyloidosis

The availability of a genetic model organism with which to study key molecular events underlying amyloidogenesis is crucial for elucidating the mechanism of the disease and the exploration of new therapeutic avenues. The natural human variant of β2-microglobulin (D76N β2-m) is associated with a fatal familial form of systemic amyloidosis. Hitherto, no animal model has been available for studying in vivo the pathogenicity of this protein. We have established a transgenic C. elegans line, expressing the human D76N β2-m variant. Using the INVertebrate Automated Phenotyping Platform (INVAPP) and the algorithm Paragon, we were able to detect growth and motility impairment in D76N β2-m expressing worms. We also demonstrated the specificity of the β2-m variant in determining the pathological phenotype by rescuing the wild type phenotype when β2-m expression was inhibited by RNA interference (RNAi). Using this model, we have confirmed the efficacy of doxycycline, an inhibitor of the aggregation of amyloidogenic proteins, in rescuing the phenotype. In future, this C. elegans model, in conjunction with the INVAPP/Paragon system, offers the prospect of high-throughput chemical screening in the search for new drug candidates

Effect of maternal panic disorder on mother-child interaction and relation to child anxiety and child self-efficacy

To determine whether mothers with panic disorder with or without agoraphobia interacted differently with their children than normal control mothers, 86 mothers and their adolescents (aged between 13 and 23 years) were observed during a structured play situation. Maternal as well as adolescent anxiety status was assessed according to a structured diagnostic interview. Results showed that mothers with panic disorder/agoraphobia showed more verbal control, were more criticizing and less sensitive during mother-child interaction than mothers without current mental disorders. Moreover, more conflicts were observed between mother and child dyadic interactions when the mother suffered from panic disorder. The comparison of parenting behaviors among anxious and non-anxious children did not reveal any significant differences. These findings support an association between parental over-control and rejection and maternal but not child anxiety and suggest that particularly mother anxiety status is an important determinant of parenting behavior. Finally, an association was found between children’s perceived self-efficacy, parental control and child anxiety symptoms