Endotracheal tubes (ETTs) constitute a resistive extra load for intubated patients. The ETT pressure drop (DeltaP(ETT)) is usually described by empirical equations that are specific to one ETT only. Our laboratory previously showed that, in adult ETTs, DeltaP(ETT) is given by the Blasius formula (F. Lofaso, B. Louis, L. Brochard, A. Harf, and D. Isabey. Am. Rev. Respir. Dis. 146: 974-979, 1992). Here, we also propose a general formulation for neonatal and pediatric ETTs on the basis of adimensional analysis of the pressure-flow relationship. Pressure and flow were directly measured in seven ETTs (internal diameter: 2.5-7.0 mm). The measured pressure drop was compared with the predicted drop given by general laws for a curved tube. In neonatal ETTs (2.5-3.5 mm) the flow regime is laminar. The DeltaP(ETT) can be estimated by the Ito formula, which replaces Poiseuille's law for curved tubes. For pediatric ETTs (4.0-7.0 mm), DeltaP(ETT) depends on the following flow regime: for laminar flow, it must be calculated by the Ito formula, and for turbulent flow, by the Blasius formula. Both formulas allow for ETT geometry and gas properties.

The effect of ingestion of the same amount (30 g) of a resistant starch (lintner) and cellulose on energy expenditure (EE), colonic fermentation (breath-hydrogen test), and blood glucose, insulin, and free fatty acid (FFA) concentrations were compared in seven healthy volunteers in a first experiment. In a second experiment the same indexes were measured in six healthy volunteers after the ingestion of diets composed of 50 g glucose alone or mixed with 30 g lintner, or cellulose, or pectin. In the first experiment no differences between lintner and cellulose were observed on the measured indexes. The notable difference was the increased apparent colonic fermentation with lintner after 6 h. In experiment 2, although insulin response was significantly lower in the pectin-added diet, the results obtained with the four different diets were not significantly different. The metabolic characteristics of lintner were closer to cellulose than to pectin. In conclusion, the acute effect of the ingestion of a resistant starch (lintner) on the measured metabolic indexes is similar to that of a known insoluble fiber--cellulose.

Preliminary testing of fuel cell catalysts in a model laboratory environment is an essential step in the technology readiness level progression of material candidates toward the commercial device. However, in the case of platinum alloy catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), there is no consensus on the protocol employed for catalyst conditioning (activation or break-in), leading to important discrepancies in the literature. Here, the effects of electrochemical conditioning on the PtNi nanocatalyst structure, chemical composition, and performance for the ORR are investigated using operando high-energy X-ray diffraction in both the liquid-electrolyte and solid-electrolyte X-ray transparent PEMFCs, online inductively coupled plasma mass spectrometry, and the rotating disk electrode (RDE) techniques, respectively. Our results show that for PtNi/C materials, the cost in ORR performance associated to complete surface stabilization at the potential of the ORR can be dramatic but can also be mitigated by adjusting the initial chemistry and structure of the catalyst. Overall, this study reveals how uncomplete catalyst conditioning in the RDE leads to highly erroneous conclusions regarding its performance and stability to be possibly found in a realistic PEMFC device and proposes simple strategies to close this gap.

the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic has caused a major health crisis. Between March 1 and April 30, SARS-CoV-2 led to an excess daily mortality of 33% compared with average values for the years 2000 to 2019. 1 As of 17th December 2020, a report published by the French National Public Health Agency indicates a cumulative number of 2 427 316 COVID-19 infected patients, with 59 619 deaths, 41 200 of these in hospital. 2 The purpose of this critical commentary is to describe the COVID-19 crisis from the perspective of French intensive care unit (ICU) nurses and to discuss how the pandemic has finally facilitated appropriate recognition for French critical care nurses. This major crisis was managed nationally by the Ministry ofHealth, but every hospital had to locally manage the increased activity due to the admissions of COVID-19 patients with its own means. Decades of political decisions to decrease health costs has led to equipment and staff deficiencies for hospitals. To cope with these limited resources, health care professionals had to create new organizations and set up new collaborations. In the first days of the pandemic in France, health authorities expected that many patients would need intensive care, and an important gap between ICU capacity and demand was feared. Before the pandemic, French ICUs were already under pressure: with only 2.4 ICU beds for 10 000 citizens, half of