514 research outputs found

    Structure of the Antarctic plate by analysis of surface-wave group speed and a global Haar-wavelet model representation

    Get PDF
    The unique tectonic setting of the Antarctic plate — all surrounded by active ocean ridges, geodynamically stationary, and crossed by the largest asymmetric continental rift — make it a very interesting subject, that recently has received increased attention because of the International Polar Year (IPY). We present a seismic tomographic study targeted at improving the resolution of previous models, by virtue of an extended dataset and a multiresolution spherical-wavelet based model representation. We limit the present study to modeling laterally-varying fundamental-mode Rayleigh wave group speed, that is mainly related to the structure of crust and uppermost mantle. We use single-station dispersion analysis on the surface wave train to measure group arrival times of the Rayleigh-wave fundamental mode in the period range between 30 and 150 s. On each seismogram we iteratively apply a multiple filter – to identify group arrival times with frequency – and a phase-matched filter, to isolate the fundamental mode within the wave train. We then use dispersion measurements to compute two-dimensional maps of wave group speed in the region. We parameterize the Earth using nearly-orthogonal spherical Haar wavelets based on iterative subdivisions of the icosahedron. This representation is particularly suited to implement multi-resolution, as needed for a regional model embedded into a global one. The model shows with increased detail important features such as the narrow transition between cratonic structure in East Antarctica and accreted West Antarctica, separated by the Transantarctic Mountains bordering the rift. Inclusion of data from temporary experiments carried on within the IPY, as they become available, will locally further improve resolution

    Meningococcal B vaccine antigen FHbp variants among disease-causing Neisseria meningitidis B isolates, Italy, 2014–2017

    Get PDF
    Background Typing of Neisseria meningitidis isolates is crucial for the surveillance of invasive meningococcal disease (IMD). We performed a molecular epidemiology study of N. meningitidis serogroup B (MenB) causing IMD in Italy between 2014 and 2017 to describe circulating strains belonging to this serogroup, with particular regards to the two factor H-binding protein (FHbp) subfamilies present in the bivalent MenB vaccine. Materials and methods A total of 109 culture positive and 46 culture negative MenB samples were collected within the National Surveillance System (NSS) of IMD in Italy and molecularly analyzed by conventional methods. Results Overall, 71 MenB samples showed the FHbp subfamily A and 83 the subfamily B. The subfamily variants were differently distributed by age. The most frequent variants, A05 and B231, were associated with cc213 and cc162, respectively. All MenB with the FHbp A05 variant displayed the PorA P1.22,14 and 85.7% of them the FetA F5-5. The majority of MenB with the FHbp B231 variant showed the PorA P1.22,14 (65.4%) and 84.6%, the FetA F3-6. Conclusion MenB circulating in Italy were characterized by a remarkable association between clonal complex and FHbp variants, although a high degree of genetic diversity observed over time. A dynamic trend in clonal complexes distribution within MenB was detected. Our results stress the importance of continued meningococcal molecular surveillance to evaluate the potential vaccine coverage of the available MenB vaccines

    THE IMPORTANCE OF DYNAMIC EFFECTS ON THE ENZYME ACTIVITY: X-RAY STRUCTURE AND MOLECULAR DYNAMICS OF ONCONASE MUTANTS.

    Get PDF
    Onconase (ONC), a member of the RNase A superfamily extracted from oocytes of Rana pipiens, is an effective cancer killer. It is currently used in treatment of various forms of cancer. ONC antitumor properties depend on its ribonucleolytic activity that is low in comparison with other members of the superfamily. The most damaging side effect from Onconase treatment is renal toxicity, which seems to be caused by the unusual stability of the enzyme. Therefore, mutants with reduced thermal stability and/or increased catalytic activity may have significant implications for human cancer chemotherapy. In this context, we have determined the crystal structures of two Onconase mutants (M23L-ONC and C87S,des103-104-ONC) and performed molecular dynamic simulations of ONC and C87S,des103-104-ONC with the aim of explaining on structural grounds the modifications of the activity and thermal stability of the mutants. The results also provide the molecular bases to explain the lower catalytic activity of Onconase compared with RNase A and the unusually high thermal stability of the amphibian enzyme

    Evolution of a single incised valley related to inherited geology, sea level rise and climate changes during the Holocene (Tirso river, Sardinia, western Mediterranean Sea)

    Get PDF
    We performed a morpho-stratigraphic study of the Tirso River incised valley (Sardinia Island, western Mediterranean Sea), an erosional feature crossing the Sinis fault, a major normal fault bordering the Campidano basin between the Gulf of Oristano and the western Sardinia shelf. High-resolution seismic reflection profiles and multibeam echosounder data, integrated by age-constrained stratigraphic logs derived from 9 sediment cores enabled us to reconstruct the valley evolution during the Holocene. We found that the Tirso valley is the result of a single event of incision and infill during the last eustatic cycle, strongly controlled by the presence of the Sinis fault. In fact, this structure represents a geological threshold that marks an abrupt change in substrate lithology and seabed slope, which controlled the valley morphology, narrow when downcutting early Pliocene formations along the steeper open shelf, and wider inside the Gulf, in the Pleistocene alluvial deposits of the flatter Gulf of Oristano. The sedimentary record starts with alluvial sediments filling the valley along the shelf during the initial phase of sea level rise, i.e., over 10 ka. During the last ~9.0 ka, a bay head delta developed, with the formation of barriers at the gulf entrance. In the mid-late Holocene, the progressive sea-level rise led to rapid drowning of the barrier system, recorded by marine and estuarine sediments filling the valley. Analysis of ecological associations in the cores, collected along a valley-normal transect, allowed for a detailed reconstruction of the paleo-environmental conditions during the latest phase of the incised valley filling controlled by global climatic variations in the Mediterranean region between ~9.0 and ~ 4.5 ka. Together with eustasy, our work reveals that the evolution and sedimentary infill of the Tirso incised valley was strongly controlled by inherited geological constraints, which influenced the morphology of the valley and the stratigraphic pattern

    Hospital Antibiotic Use during COVID-19 Pandemic in Italy

    Get PDF
    Antimicrobial resistance (AMR) represents a major issue in healthcare being correlated to global inappropriate use of antibiotics. The aim of this study was to compare the data on hospital antibiotic consumption in 2020–2021 with those related to 2019 in order to evaluate the impact of the COVID-19 pandemic on antibiotic prescriptions and appropriate use at national level and in the different geographical areas. To estimate the consumption of antibiotics, two indicators were calculated: “number of DDD per 1000 inhabitants per day” and “number of DDD per 100 hospitalisation days”. Consumption data on antibiotics dispensed in public health facilities were based on the Italian “traceability of medicines” information flow. Data on hospitalisation days were extracted from the Italian “hospital discharge form” flow. Pearson correlation analysis was performed between the number of patients hospitalised for COVID-19 and the consumption of antibiotics in public healthcare facilities. During 2020, about 1.7 DDD/1000 inhabitants per day (12.3% of the overall consumption of reimbursed antibiotics) were dispensed exclusively in Italian hospitals (+0.8% compared to 2019). Considering the number of DDD per 100 hospitalisation days, consumption increased by 19.3% in 2020 compared to 2019. Comparing the first semester of 2020 and 2019, a decrease of DDD/1000 inhabitants per day was observed (−1.6%) at national level, with opposite trends in the different geographical areas; an increase in the use of azithromycin and carbapenems was also observed, with a stable consumption of third-generation cephalosporins. The use of antibiotics in the second semester of 2020 compared to the same period of 2019 showed a clear reduction at national level (−8.5%), appreciable to a similar extent in all geographic areas. In the first semester of 2021 compared to the same period of 2020, there was a huge reduction (−31.4%) in consumption at national level. However, the variations were heterogeneous between different geographical areas. To our knowledge, this study represents the most comprehensive analysis performed on antibiotic consumption data in hospital settings in Italy during the COVID-19 pandemic to date. Despite international and national guideline recommendations, a substantial overall increase in antibiotic prescriptions was observed during the COVID-19 pandemic, with variability in terms of geographical distribution and prescription strategies. These findings may be related to the dichotomy between perceived and real significance of guidelines, expert panels, or consensus. Therefore, new approaches or strategies to antimicrobial stewardship should be proposed

    Diversity of Neisseria meningitidis invasive isolates in Italy in the period 2008-2010

    Get PDF
    In the period 2008-2010, 309 Neisseria meningitidis, isolated in Italy within the National Surveillance of the Invasive Meningococ- cal Diseases, have been tested for their phenotypic and genotypic characteristics. The main results obtained are: (a) an increase of the strains of serogroup B and a decrease of serogroup C; (b) a phenotypic and genotypic variability of the ST-41/44 clonal complex, the most frequently isolated among serogroup B strains; (c) a decrease of ST-8 clonal complex among serogroup C menin- gococci whereas strains belonging to ST-11 clonal complex are nowadays the most frequently isolated. The full article is free available on www.jpmh.or

    Esperienze di monitoraggio integrato: il caso della Rete Sismometrica dell’Italia centro orientale e dei suoi servizi

    Get PDF
    Viene presentata l’esperienza maturata dagli operatori della sede di Ancona dell’INGV (INGV-AN) nell’ambito delle collaborazioni tra l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e la Regione Marche per il miglioramento delle attivitĂ  di monitoraggio sismico. L’attivitĂ  dell’INGV-AN aveva due scopi: migliorare le conoscenze sulla sismicitĂ  regionale a fini scientifici e perfezionare il servizio di informazione svolto per il Dipartimento per le Politiche Integrate di Sicurezza e per la Protezione Civile (DPISPC). Per il raggiungimento degli scopi si Ăš proceduto all’incremento del numero di stazioni, alla trasformazione in real- time della vecchia rete dial-up, alla installazione di nuove stazioni accelerometriche, e all’utilizzo del complesso dei dati raccolti dalle stazioni accelerometriche e velocimetriche in funzione nel territorio regionale e in quelli immediatamente limitrofi, nonchĂ© allo scambio dati tra la sede INGV di Ancona e quella di Roma. I costi dell’intera operazione sono stati contenuti grazie all’utilizzo delle infrastrutture radio wireless della Regione Marche, della economica trasmissione UMTS, di acquisitori GAIA sviluppati dall’INGV e di economici ma efficaci accelerometri MEMS SF3000L della Colybris. Gli obiettivi raggiunti sono i presupposti per il proseguimento della collaborazione tra i due enti rivolta alla copertura piĂč ampia possibile del territorio regionale con reti di rilevamento accelerometrico a basso costo e alla realizzazione di servizi sempre piĂč finalizzati all’emergenza sismica

    Ceftolozane/tazobactam for the treatment of serious Pseudomonas aeruginosa infections: a multicentre nationwide clinical experience

    Get PDF
    This study describes the largest clinical experience using ceftolozane/tazobactam (C/T) for different Pseudomonas aeruginosa infections. A retrospective study was performed at 22 hospitals in Italy (June 2016\u2013March 2018). All adult patients treated with 654 days of C/T were enrolled. Successful clinical outcome was defined as complete resolution of clinical signs/symptoms related to P. aeruginosa infection and lack of microbiological evidence of infection. C/T treatment was documented in 101 patients with diverse infections, including nosocomial pneumonia (31.7%), acute bacterial skin and skin-structure infection (20.8%), complicated UTI (13.9%), complicated IAI (12.9%), bone infection (8.9%) and primary bacteraemia (5.9%). Over one-half of P. aeruginosa strains were XDR (50.5%), with 78.2% of isolates resistant to at least one carbapenem. C/T was used as first-line therapy in 39 patients (38.6%). When used as second-line or later, the most common reasons for discontinuation of previous antibiotics were in vitro resistance of P. aeruginosa and clinical failure of previous therapy. Concomitant antibiotics were reported in 35.6% of patients. C/T doses were 1.5 g q8h in 70 patients (69.3%) and 3 g q8h in 31 patients (30.7%); median duration of C/T therapy was 14 days. Overall clinical success was 83.2%. Significant lower success rates were observed in patients with sepsis or receiving continuous renal replacement therapy (CRRT). Mild adverse events were reported in only three patients. C/T demonstrated a favourable safety and tolerability profile regardless of the infection type. Clinicians should be aware of the risk of clinical failure with C/T therapy in septic patients receiving CRRT
    • 

    corecore