EXTUBATE: A randomised controlled trial of nasal biphasic positive airway pressure vs. nasal continuous positive airway pressure following extubation in infants less than 30 weeks' gestation: study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Respiratory distress syndrome remains a significant problem among premature infants. Mechanical ventilation through an endotracheal tube remains the mainstay of respiratory support but may be associated with lung injury and the development of chronic lung disease of prematurity. Efforts are needed to reduce the duration of mechanical ventilation in favour of less invasive forms of respiratory support and to improve rates of successful extubation.</p> <p>Non-invasive respiratory support has been demonstrated to be less injurious to the premature lung. Standard practice is to use nasal continuous positive airway pressure (n-CPAP) following extubation to support the baby's breathing. Many clinicians also use nasal biphasic positive airway pressure (n-BiPAP) in efforts to improve rates of successful extubation. However, there is currently no evidence that this confers any advantage over conventional nasal continuous positive airway pressure.</p> <p>Methods</p> <p>We propose an unblinded multi-centre randomised trial comparing n-CPAP with n-BiPAP in babies born before 30 weeks' gestation and less than two weeks old. Babies with congenital abnormalities and severe intra-ventricular haemorrhage will be excluded. 540 babies admitted to neonatal centres in England will be randomised at the time of first extubation attempt. The primary aim of this study is to compare the rate of extubation failure within 48 hours following the first attempt at extubation. The secondary aims are to compare the effect of n-BiPAP and n-CPAP on the following outcomes:</p> <p>1. Maintenance of successful extubation for 7 days post extubation</p> <p>2. Oxygen requirement at 28 days of age and at 36 weeks' corrected gestational age</p> <p>3. Total days on ventilator, n-CPAP/n-BiPAP</p> <p>4. Number of ventilator days following first extubation attempt</p> <p>5. pH and partial pressure of carbon dioxide in the first post extubation blood gas</p> <p>6. Duration of hospital stay</p> <p>7. Rate of abdominal distension requiring cessation of feeds</p> <p>8. Rate of apnoea and bradycardia</p> <p>9. The age at transfer back to referral centre in days</p> <p>The trial will determine whether n-BiPAP is safe and superior to n-CPAP in preventing extubation failure in babies born before 30 weeks' gestation and less than two weeks old.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN18921778">ISRCTN18921778</a></p

A dual weighted residual method applied to complex periodic gratings

An extension of the dual weighted residual (DWR) method to the analysis of electromagnetic waves in a periodic diffraction grating is presented. Using the α,0-quasi-periodic transformation, an upper bound for the a posteriori error estimate is derived. This is then used to solve adaptively the associated Helmholtz problem. The goal is to achieve an acceptable accuracy in the computed diffraction efficiency while keeping the computational mesh relatively coarse. Numerical results are presented to illustrate the advantage of using DWR over the global a posteriori error estimate approach. The application of the method in biomimetic, to address the complex diffraction geometry of the Morpho butterfly wing is also discussed

Statistical Evaluation of NDE Reliability in the Aerospace Industry

The goal of this paper is to review the statistical methods used in the aerospace industries to evaluate NDE reliability. The techniques presented are consistent with the damage tolerant design and structural maintenance philosophies of the aerospace industry. The first part of this paper establishes the evaluation criteria and discusses the history of NDE reliability evaluations. The second part describes the state-of-the-art analysis methods through examples from the retirement for cause (RFC) inspection system evaluation. The last part of the paper discusses some techniques used to rate operator performance and deal with false calls

The Emerging Scholarly Brain

It is now a commonplace observation that human society is becoming a coherent super-organism, and that the information infrastructure forms its emerging brain. Perhaps, as the underlying technologies are likely to become billions of times more powerful than those we have today, we could say that we are now building the lizard brain for the future organism.Comment: to appear in Future Professional Communication in Astronomy-II (FPCA-II) editors A. Heck and A. Accomazz

Comment mesurer les progrès de la lecture?

New observations of Neptune’s clouds in the near infrared were acquired in October 2013 with SINFONI on ESO’s Very Large Telescope (VLT) in Chile. SINFONI is an Integral Field Unit spectrometer returning a 64 × 64 pixel image with 2048 wavelengths. Image cubes in the J-band (1.09 – 1.41 μm) and H-band (1.43 – 1.87 μm) were obtained at spatial resolutions of 0.1″and 0.025″per pixel, while SINFONI’s adaptive optics provided an effective resolution of approximately 0.1″. Image cubes were obtained at the start and end of three successive nights to monitor the temporal development of discrete clouds both at short timescales (i.e. during a single night) as well as over the longer period of the three-day observing run. These observations were compared with similar H-band observations obtained in September 2009 with the NIFS Integral Field Unit spectrometer on the Gemini-North telescope in Hawaii, previously reported by Irwin et al., Icarus 216, 141-158, 2011, and previously unreported Gemini/NIFS observations at lower spatial resolution made in 2011. We find both similarities and differences between these observations, spaced over four years. The same overall cloud structure is seen with high, bright clouds visible at mid-latitudes (30 – 40°N,S), with slightly lower clouds observed at lower latitudes, together with small discrete clouds seen circling the pole at a latitude of approximately 60°S. However, while discrete clouds were visible at this latitude at both the main cloud deck level (at 2–3 bars) and in the upper troposphere (100–500mb) in 2009, no distinct deep (2–3 bar), discrete circumpolar clouds were visible in 2013, although some deep clouds were seen at the southern edge of the main cloud belt at 30–40°S, which have not been observed before. The nature of the deep sub-polar discrete clouds observed in 2009 is intriguing. While it is possible that in 2013 these deeper clouds were masked by faster moving, overlying features, we consider that it is unlikely that this should have happened in 2013, but not in 2009 when the upper-cloud activity was generally similar. Meanwhile, the deep clouds seen at the southern edge of the main cloud belt at 30 – 40°S in 2013, should also have been detectable in 2009, but were not seen. Hence, these observations may have detected a real temporal variation in the occurrence of Neptune’s deep clouds, pointing to underlying variability in the convective activity at the pressure of the main cloud deck at 2–3 bars near Neptune’s south pole and also in the main observable cloud belt at 30 – 40°S.</p

Predicting the Need for Ventilation in Term and Near-Term Neonates

To determine whether the need for respiratory support can be predicted by oxygen requirement within the first 72 h in term and near-term infants. Methods: To mimic the population of infants that would often be delivered outside a tertiary centre we studied a retrospective cohort of infants greater than or equal to 32 weeks requiring oxygen, divided into three groups: cot oxygen only, nasal continuous positive airway pressure (NCPAP) only, or intermittent positive pressure ventilation (IPPV). We recorded each infant's peak fraction of inspired oxygen (FiO2) - i.e. FiO 2 in the first 72 h in the cot oxygen only group or maximum FiO2 prior to commencing the highest level of respiratory support. The peak FiO2 was used as a diagnostic test to predict any respiratory support or IPPV-sensitivity and specificity were calculated and receiver operating characteristic (ROC) curves plotted (FiO2 0.21-1.00) to identify the best balance point for prediction. Results: The cohort included 592 infants: 516 cot oxygen only, 46 NCPAP only and 30 IPPV. The proportion ventilated increased with increasing peak FiO2 - above 0.45 the proportion of infants ventilated exceeded 50%. To predict any respiratory support, the cut-point balancing sensitivity and specificity was a FiO2 greater than or equal to 0.35-58/136 required respiratory support (sensitivity = 0.76, specificity = 0.85, positive predictive value (PPV) = 43%, negative predictive value (NPV) = 96%). To predict IPPV the cut-point was a FiO2 greater than or equal to 0.5-28/47 treated with IPPV (sensitivity = 0.93, specificity = 0.97, PPV = 60%, NPV = 100%). Conclusion: The need for respiratory support can be predicted by oxygen requirement within the first 72 h in term and near-term infants with reasonable sensitivity and excellent specificity

Post-translational insertion of boron in proteins to probe and modulate function

Boron is absent in proteins, yet is a micronutrient. It possesses unique bonding that could expand biological function including modes of Lewis acidity not available to typical elements of life. Here we show that post-translational Cβ–Bγ bond formation provides mild, direct, site-selective access to the minimally sized residue boronoalanine (Bal) in proteins. Precise anchoring of boron within complex biomolecular systems allows dative bond-mediated, site-dependent protein Lewis acid–base-pairing (LABP) by Bal. Dynamic protein-LABP creates tunable inter- and intramolecular ligand–host interactions, while reactive protein-LABP reveals reactively accessible sites through migratory boron-to-oxygen Cβ–Oγ covalent bond formation. These modes of dative bonding can also generate de novo function, such as control of thermo- and proteolytic stability in a target protein, or observation of transient structural features via chemical exchange. These results indicate that controlled insertion of boron facilitates stability modulation, structure determination, de novo binding activities and redox-responsive ‘mutation’

Post-translational insertion of boron in proteins to probe and modulate function

Boron is absent in proteins, yet is a micronutrient. It possesses unique bonding that could expand biological function including modes of Lewis acidity not available to typical elements of life. Here we show that post-translational Cβ–Bγ bond formation provides mild, direct, site-selective access to the minimally sized residue boronoalanine (Bal) in proteins. Precise anchoring of boron within complex biomolecular systems allows dative bond-mediated, site-dependent protein Lewis acid–base-pairing (LABP) by Bal. Dynamic protein-LABP creates tunable inter- and intramolecular ligand–host interactions, while reactive protein-LABP reveals reactively accessible sites through migratory boron-to-oxygen Cβ–Oγ covalent bond formation. These modes of dative bonding can also generate de novo function, such as control of thermo- and proteolytic stability in a target protein, or observation of transient structural features via chemical exchange. These results indicate that controlled insertion of boron facilitates stability modulation, structure determination, de novo binding activities and redox-responsive ‘mutation’