Feasibility of non-invasive pressure support ventilation in infants with respiratory failure after extubation: a pilot study

Objective: To evaluate the feasibility and effects of non-invasive pressure support ventilation (NIV) on the breathing pattern in infants developing respiratory failure after extubation. Design: Prospective pilot clinical study; each patient served as their own control. Setting: A nine-bed paediatric intensive care unit of a tertiary university hospital. Patients: Six patients (median age 5months, range 0.5-7months; median weight 4.2kg, range 3.8-5.1kg) who developed respiratory failure after extubation. Interventions: After a period of spontaneous breathing (SB), children who developed respiratory failure were treated with NIV. Measurements and results: Measurements included clinical dyspnoea score (DS), blood gases and oesophageal pressure recordings, which were analysed for respiratory rate (RR), oesophageal inspiratory pressure swing (dPes) and oesophageal pressure-time product (PTPes). All data were collected during both periods (SB and NIV). When comparing NIV with SB, DS was reduced by 44% (P<0.001), RR by 32% (P<0.001), dPes by 45% (P<0.01) and PTPes by 57% (P<0.001). A non-significant trend for decrease in PaCO2 was observed. Conclusion: In these infants, non-invasive pressure support ventilation with turbine flow generator induced a reduction of breathing frequency, dPes and PTPes, indicating reduced load of the inspiratory muscles. NIV can be used with some benefits in infants with respiratory failure after extubatio

The wonders of flap endonucleases: structure, function, mechanism and regulation.

Processing of Okazaki fragments to complete lagging strand DNA synthesis requires coordination among several proteins. RNA primers and DNA synthesised by DNA polymerase α are displaced by DNA polymerase δ to create bifurcated nucleic acid structures known as 5'-flaps. These 5'-flaps are removed by Flap Endonuclease 1 (FEN), a structure-specific nuclease whose divalent metal ion-dependent phosphodiesterase activity cleaves 5'-flaps with exquisite specificity. FENs are paradigms for the 5' nuclease superfamily, whose members perform a wide variety of roles in nucleic acid metabolism using a similar nuclease core domain that displays common biochemical properties and structural features. A detailed review of FEN structure is undertaken to show how DNA substrate recognition occurs and how FEN achieves cleavage at a single phosphate diester. A proposed double nucleotide unpairing trap (DoNUT) is discussed with regards to FEN and has relevance to the wider 5' nuclease superfamily. The homotrimeric proliferating cell nuclear antigen protein (PCNA) coordinates the actions of DNA polymerase, FEN and DNA ligase by facilitating the hand-off intermediates between each protein during Okazaki fragment maturation to maximise through-put and minimise consequences of intermediates being released into the wider cellular environment. FEN has numerous partner proteins that modulate and control its action during DNA replication and is also controlled by several post-translational modification events, all acting in concert to maintain precise and appropriate cleavage of Okazaki fragment intermediates during DNA replication

Obstacles in pedestrian simulations

This report presents two new models to simulate the behavior of pedestrians. The first model uses a potential field model approach invented by Hoogendoorn and Bovy, but calculates the field using a wave algorithm instead of partial differential equations. The second model uses significant points in the environment to generate first a visibility graph and then a minimal spanning tree using the algorithm from Dijkstra. The walking direction and speed of the pedestrians depends on three forces similar to the social force model by Helbing. The first force leads the agent toward its destination by using either the potential field or the calculated spanning tree. A second force regulates the interactions between agents, so ensuring that agents do not walk into other pedestrians and try to keep a certain distance from each other. The third force guarantees that agents do not walk into walls and that they try to keep a certain distance from walls. The behavior of pedestrians simulated with the two models is quite similar, the main difference lies in the models ’ performance. The spanning tree approach is slower than the potential field model when simple simulations are used, as it spends most time on the creation of the visibility graph. The advantages of the spanning tree model are found when more sophisticated simulations with different destinations are run, as all spannin

Redox properties of structural Fe in ferruginous smectite. A discussion of the standard potential and its environmental implications

International audienceThe aim of this study was to compare the redox properties of oxides and smectite structural Fe (FeStr). Structural Fe in smectite often accounts for about half of the Fe pool in soils and sediments, and is naturally reduced by indigenous bacteria. This reaction is, however, seldom taken into account in environmental studies. The equation for the oxidation-reduction of FeStr and its application to the calculation of the standard electrode potential of FeStr, E0, are discussed on the basis of literature review. The resulting redox properties were used in a new analysis of previously reported field monitoring data. This agreed well with experimental observations that remained unexplained, and showed that if equilibrium conditions prevail, the FeStr pool in soils will reduce prior to the Fe in oxides. The FeStr pool is, therefore, likely to play a major role in controlling the bio-geochemistry of temporarily water-logged soils, and this reaction should be taken into account in further studies

Rediscovery of Stactobia eatoniella McLachlan, 1880 (Trichoptera, Hydroptilidae) in Switzerland after more than seventy years

A specimen of Stactobia eatoniella, a hygropetric species of micro-caddisfly considered extinct in Switzerland, was discovered in the Morge in Valais in March 2020 during routine monitoring. This last instar larva in perfect condition is the first to be observed in Switzerland since 1944. Further research in the study area is needed to confirm the presence of a possible well-established population. This encouraging discovery should not hide the fact that two thirds of the micro-caddisfly species are on the Red List of threatened species of Switzerland, and that hygropetric habitats are both under-studied and highly endangered in Switzerland and worldwide