Comparison of “IN-REC-SUR-E” and LISA in preterm neonates with respiratory distress syndrome: a randomized controlled trial (IN-REC-LISA trial)

Background: Surfactant is a well-established therapy for preterm neonates affected by respiratory distress syndrome (RDS). The goals of different methods of surfactant administration are to reduce the duration of mechanical ventilation and the severity of bronchopulmonary dysplasia (BPD); however, the optimal administration method remains unknown. This study compares the effectiveness of the INtubate-RECruit-SURfactant-Extubate (IN-REC-SUR-E) technique with the less-invasive surfactant administration (LISA) technique, in increasing BPD-free survival of preterm infants. This is an international unblinded multicenter randomized controlled study in which preterm infants will be randomized into two groups to receive IN-REC-SUR-E or LISA surfactant administration. Methods: In this study, 382 infants born at 24+0–27+6 weeks’ gestation, not intubated in the delivery room and failing nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV) during the first 24 h of life, will be randomized 1:1 to receive IN-REC-SUR-E or LISA surfactant administration. The primary outcome is a composite outcome of death or BPD at 36 weeks’ postmenstrual age. The secondary outcomes are BPD at 36 weeks’ postmenstrual age; death; pulse oximetry/fraction of inspired oxygen; severe intraventricular hemorrhage; pneumothorax; duration of respiratory support and oxygen therapy; pulmonary hemorrhage; patent ductus arteriosus undergoing treatment; percentage of infants receiving more doses of surfactant; periventricular leukomalacia, severe retinopathy of prematurity, necrotizing enterocolitis, sepsis; total in-hospital stay; systemic postnatal steroids; neurodevelopmental outcomes; and respiratory function testing at 24 months of age. Randomization will be centrally provided using both stratification and permuted blocks with random block sizes and block order. Stratification factors will include center and gestational age (24+0 to 25+6 weeks or 26+0 to 27+6 weeks). Analyses will be conducted in both intention-to-treat and per-protocol populations, utilizing a log-binomial regression model that corrects for stratification factors to estimate the adjusted relative risk (RR). Discussion: This trial is designed to provide robust data on the best method of surfactant administration in spontaneously breathing preterm infants born at 24+0–27+6 weeks’ gestation affected by RDS and failing nCPAP or NIPPV during the first 24 h of life, comparing IN-REC-SUR-E to LISA technique, in increasing BPD-free survival at 36 weeks’ postmenstrual age of life. Trial registration: ClinicalTrials.gov NCT05711966. Registered on February 3, 2023

Experimental Study of Very Low Aspect Ratio Wings in Slender Bodies

The dynamics of very low aspect ratio wings (or strakes) vortices in slender bodies are complex due to the interaction of the shed vortex sheet and the body vortex. For missiles at supersonic speeds these interactions are not easily predicted using engineering level tools. To shed some new light onto this problem, an experimental study in a water channel for moderate Reynolds number (Re = 1000) was performed for a 19D body and strake configuration with strakes having a span to body diameter ratio of 1.25. Comparisons to numerical simulations in supersonic flow are also performed. Flow visualisation has been carried out to characterize the vortex dynamics at different angles of attack; these being 11°, 16°, 22° and 27°. The comparison between a slender body without strakes and the body-strake configuration has given some key indicators in relation to the vortex position of the core. Furthermore, unsteady wing-body interference has been observed at angles of attack above 20° for both experimental and numerical simulations. Consequently, the average position of the vortex core is located at larger distances from the missile in comparison to the body without strakes. The numerical simulations show good correlation with the experimental tests even though the dynamic convective interactions between the body vortex and strake vortex sheet are not predicted.</jats:p

Application of the Morphing Camber Concept to a Regional Aircraft

The paper summarizes the recent activities performed at inside FP7-NOVEMOR project related to the application of morphing technologies and in particular the variable camber concept. After a short reminder on the tools developed aiming at the design of variable camber morphing wings, the paper describes the main results obtained from the application of this morphing concept to a typical regional aircraft. Finally, the validation activities by means of the wind tunnel test campaigns are briefly introduced

Two-dimensional potential method simulations of a body-strake configuration

The lee-side flow over a cruciform wing-body configuration at supersonic speeds in the "+" orientation up to angles of 25 deg have been simulated using the single concentrated vortex and discrete vortex model methods. The wings or strakes are of very low aspect ratio of order 0.025 with taper ratio ≈1 with a length of 11.25 Dmounted on a 19D tangent ogive body. The simulations revealed that the single concentrated vortex model is only suitable at low angles, while the discrete vortex model can predict both the flowfield and normal force reasonably when the lee-side boundary-layer separation characteristics are modeled. The resulting secondary vortex due to the wing-body junction has been identified to significantly influence the lee-side flow topology, and its exclusion results in higher normal forces and incorrect prediction of vortex positions. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc