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Shark scales on fast-swimming sharks have been shown to be movable to angles in excess of 50°, and we hypothesize that this characteristic gives this shark skin a preferred flow direction. During the onset of separation, flow reversal is initiated close to the surface. However, the movable scales would be actuated by the reversed flow thereby causing a greater resistance to any further flow reversal and this mechanism would disrupt the process leading to eventual flow separation. Here we report for the first time experimental evidence of the separation control capability of real shark skin through water tunnel testing. Using skin samples from a shortfin mako Isurus oxyrinchus, we tested a pectoral fin and flank skin attached to a NACA 4412 hydrofoil and separation control was observed in the presence of movable shark scales under certain conditions in both cases. We hypothesize that the scales provide a passive, flow-actuated mechanism acting as a dynamic micro-roughness to control flow separation.

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Summary To better understand outcomes in postpartum patients who receive peripartum anaesthetic interventions, we aimed to assess quality of recovery metrics following childbirth in a UK‐based multicentre cohort study. This study was performed during a 2‐week period in October 2021 to assess in‐ and outpatient post‐delivery recovery at 1 and 30 days postpartum. The following outcomes were reported: obstetric quality of recovery 10‐item measure (ObsQoR‐10); EuroQoL (EQ‐5D‐5L) survey; global health visual analogue scale; postpartum pain scores at rest and movement; length of hospital stay; readmission rates; and self‐reported complications. In total, 1638 patients were recruited and responses analysed from 1631 (99.6%) and 1282 patients (80%) at one and 30 days postpartum, respectively. Median (IQR [range]) length of stay postpartum was 39.3 (28.5–61.0 [17.7–513.4]), 40.3 (28.5–59.1 [17.8–220.9]), and 35.9 (27.1–54.1 [17.9–188.4]) h following caesarean, instrumental and vaginal deliveries, respectively. Median (IQR [range]) ObsQoR‐10 score was 75 ([62–86] 4–100) on day 1, with the lowest ObsQoR‐10 scores (worst recovery) reported by patients undergoing caesarean delivery. Of the 1282 patients, complications within the first 30 days postpartum were reported by 252 (19.7%) of all patients. Readmission to hospital within 30 days of discharge occurred in 69 patients (5.4%), with 49 (3%) for maternal reasons. These data can be used to inform patients regarding expected recovery trajectories; facilitate optimal discharge planning; and identify populations that may benefit most from targeted interventions to improve postpartum recovery experience.

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