29 research outputs found
Efficacy of a new technique - INtubate-RECruit-SURfactant-Extubate - "IN-REC-SUR-E" - in preterm neonates with respiratory distress syndrome: Study protocol for a randomized controlled trial
Background: Although beneficial in clinical practice, the INtubate-SURfactant-Extubate (IN-SUR-E) method is not successful in all preterm neonates with respiratory distress syndrome, with a reported failure rate ranging from 19 to 69 %. One of the possible mechanisms responsible for the unsuccessful IN-SUR-E method, requiring subsequent re-intubation and mechanical ventilation, is the inability of the preterm lung to achieve and maintain an "optimal" functional residual capacity. The importance of lung recruitment before surfactant administration has been demonstrated in animal studies showing that recruitment leads to a more homogeneous surfactant distribution within the lungs. Therefore, the aim of this study is to compare the application of a recruitment maneuver using the high-frequency oscillatory ventilation (HFOV) modality just before the surfactant administration followed by rapid extubation (INtubate-RECruit-SURfactant-Extubate: IN-REC-SUR-E) with IN-SUR-E alone in spontaneously breathing preterm infants requiring nasal continuous positive airway pressure (nCPAP) as initial respiratory support and reaching pre-defined CPAP failure criteria. Methods/design: In this study, 206 spontaneously breathing infants born at 24+0-27+6 weeks' gestation and failing nCPAP during the first 24 h of life, will be randomized to receive an HFOV recruitment maneuver (IN-REC-SUR-E) or no recruitment maneuver (IN-SUR-E) just prior to surfactant administration followed by prompt extubation. The primary outcome is the need for mechanical ventilation within the first 3 days of life. Infants in both groups will be considered to have reached the primary outcome when they are not extubated within 30 min after surfactant administration or when they meet the nCPAP failure criteria after extubation. Discussion: From all available data no definitive evidence exists about a positive effect of recruitment before surfactant instillation, but a rationale exists for testing the following hypothesis: a lung recruitment maneuver performed with a step-by-step Continuous Distending Pressure increase during High-Frequency Oscillatory Ventilation (and not with a sustained inflation) could have a positive effects in terms of improved surfactant distribution and consequent its major efficacy in preterm newborns with respiratory distress syndrome. This represents our challenge. Trial registration: ClinicalTrials.gov identifier: NCT02482766. Registered on 1 June 2015
ï»żNotulae to the Italian alien vascular flora: 14
In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia
ï»żNotulae to the Italian alien vascular flora: 14
In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material
Determination of melamine in food by high performance liquid chromatography-UV detector.
Discharge of size segregated powders from a 2D - aerated silo
The effects of aeration on the discharge of silos loaded with initially segregated particles have been evaluated. Experiments were carried out on a two-dimensional laboratory-scale aerated silo, loaded according to either ideal or controlled natural segregation patterns. Two different systems of powders made up of two size cuts were tested, one system belonging to group A and the other to group B of the Geldart classification. One of the two cuts was colored to visualize the segregation changes and the solids flow during discharge. Time variations of the discharged solids discharged were evaluated by means of a rotating sample. Results of aerated discharge were compared with mass flow discharge. From analysis of the experimental results, it is possible to conclude that aerated discharges can effectively promote the uniform solids discharge of horizontally segregated solids of group A powders. In contrast, further segregation occurs for aerated discharges of group B powders below the minimum for fluidization
Rheological and mechanical properties of Nylon 6 nanocomposites submitted to reprocessing with single and twin extruders
Abstract
The effect of multiple extrusions on nanostructure and properties of nylon 6 nanocomposites was investigated. Nanocomposites at different silicate loadings were produced by melt compounding and submitted to further reprocessing by using single and twin screw extruders. Rheological, morphological and mechanical analyses were carried out on as-produced and reprocessed samples in order to explore the influence of the number and the type of extrusion cycles on silicate nanodispersion. Rheological measurements, correlated to TEM analyses, were used to probe the nanoscale arrangement developed with the reprocessing as well as the thermo-mechanical degradation involving both the neat matrix and the organoclay. The results have shown that the reprocessing by single screw extruder can modify the initial morphology since the re-agglomeration of the silicate layers can occur. On the other hand, a better nanodispersion was observed in the hybrids reprocessed by twin screw extruder. This was attributed to the additional mechanical stresses able to realizing a dispersive mixing that contributes to avoid re-agglomeration phenomena. The high shear stresses produced with twin screw geometry determined also a significant degradation of neat matrix, principally based on chain scission mechanism. A strong correlation between the rheological behaviour and mechanical properties was observed and all as-produced and reprocessed hybrids showed a substantial enhancement in tensile modulus with the adding of silicate. However, the entity of performance enhancements displayed by the reprocessed hybrids was found to be highly dependent on the degradation of both organoclay and polymer matrix as well as the silicate amount, the number and the type reprocessing
Mineralogical and Technological Characterization of Zeolites from Basin and Range as Pozzolanic Addition of Cement
The present paper assesses petrographic, mineralogical, chemical, and technological features of different zeolitic tuff samples from various western USA districts of the Basin and Range Province containing mainly erionite, mordenite, clinoptilolite/heulandite and phillipsite. The aim of this characterization is to evaluate the pozzolanic activity of these samples according to European normative UNI-EN 196/5 (Fratini test) to program a possible use as addition for blended cements. Petrographic and mineralogical results show that the two phillipsite-bearing tuffs have a higher theoretical Cation Exchange Capacity (CEC) than the other samples; technological characterization shows a pozzolanic behavior for all the samples but higher for the tuff samples containing phillipsite, which shows a higher reactivity with CaO. All the samples could be thus advantageously employed for the preparation of blended cements, potentially reducing CO2 emissions by 70–90%
Raccolta, caratterizzazione, valorizzazione e tutela di âtipi morfologiciâ di fagiolo (Phaseolus vulgaris L.) per l'ottenimento di produzioni tipiche certificate nel Parco del Cilento
Monitoring the genetic resources still âin situâ cultivating and keeping allowed to identify ecotype and natural population genetically stable in particular environments. In Casalbuono (SA) territory in âParco del Cilentoâ, South Italy, 97 common bean accessions were collected in the kitchen garden for family use: 39 with determinate and 58 with indeterminate growth habit. All accessions were grouped in 18 âmorphological typeâ by seed trait analysis and farmer interviews. The phaseolin patterns showed that the accessions were the 98.12% from Andean (âTâ e âCâ phaseolin type) and the 9.88% from Mesoamerican (âSâ phaseolin type) origin. Common bean determinate growth habit accessions had not âCâ phaseolin type. These results allowed to begin drawing up a technical policies for production of Casalbuono (SA) certificated common bean
Authigenic mineralization in Surtsey basaltic tuff deposits at 50Â years after eruption
Abstract Alteration of basaltic glass and in situ mineral growth are fundamental processes that influence the chemical and material properties of Earthâs oceanic crust. These processes have evolved at the basaltic island of Surtsey (SW Iceland) since eruptions terminated in 1967. Here, subaerial and submarine lapilli tuff samples from a 192Â m-deep borehole drilled in 2017 (SE-02b) are characterized through petrographic studies, X-ray powder diffraction analyses, and SEMâEDS imaging and chemical analyses. The integrated results reveal (i) multi-stage palagonitization processes in basaltic glass and precipitation of secondary minerals from matrix pore fluids, (ii) multi-stage crystallization of secondary phillipsite, analcime and Al-tobermorite in the vesicles of basaltic pyroclasts and (iii) variations in palagonitization processes as a function of thermal and hydrological domains. Although temperature appears to be an important factor in controlling rates of secondary mineralization, the chemistry of original basaltic components and interstitial fluids also influences reaction pathways in the young pyroclastic deposits. The integration of systematic mineralogical analyses of the 50-year-old tuff from one of the most carefully monitored volcanic sites on Earth, together with temperature monitoring in boreholes since 1980, provide a reference framework for evaluating mineralogical evolution in other Surtseyan-type volcanoes worldwide
Ancient Roman Mortars from Anfiteatro Flavio (Pozzuoli, Southern Italy): A Mineralogical, Petrographic and Chemical Study
This research is based on the characterization of ancient mortars from the Anfiteatro Flavio (Pozzuoli) dating back to the 1st and 2nd century CE through a multi-analytical approach involving macroscopic, mineralogical, petrographic, and chemical investigations. The goal that has been set is to deepen knowledge about mortar mix design, the provenance of used raw materials, and secondary minerogenetic processes that have occurred within ancient Roman mortars. Results show that: (i) raw materials for mortar preparation have a local provenance, i.e., Phlegraean Fields area; (ii) mortars can be considered as hydraulic; (iii) calcite presence could be due to a non-complete calcination process, an improper slaking or to exposition of materials to the subaerial environment; (iv) gypsum is due to calcite sulfation process; (v) halite presence is due to marine aerosol exposition. The achieved information testifies that, for at least two centuries, Roman builders considered the identified mortar mix as optimal for their buildings, but also contributes to the understanding of their technical skills and represents an important first step to planning future restoration operations