Musculoskeletal systems cope with many environmental perturbations without neurological control. These passive preflex responses aid animals to move swiftly through complex terrain. Whether preflexes play a substantial role in animal flight is uncertain. We investigated how birds cope with gusty environments and found that their wings can act as a suspension system, reducing the effects of vertical gusts by elevating rapidly about the shoulder. This preflex mechanism rejected the gust impulse through inertial effects, diminishing the predicted impulse to the torso and head by 32% over the first 80 ms, before aerodynamic mechanisms took effect. For each wing, the centre of aerodynamic loading aligns with the centre of percussion, consistent with enhancing passive inertial gust rejection. The reduced motion of the torso in demanding conditions simplifies crucial tasks, such as landing, prey capture and visual tracking. Implementing a similar preflex mechanism in future small-scale aircraft will help to mitigate the effects of gusts and turbulence without added computational burden.

In gliding flight, birds morph their wings and tails to control their flight trajectory and speed. Using high-resolution videogrammetry, we reconstructed accurate and detailed three-dimensional geometries of gliding flights for three raptors (barn owl,Tyto alba; tawny owl,Strix aluco, and goshawk,Accipiter gentilis). Wing shapes were highly repeatable and shoulder actuation was a key component of reconfiguring the overall planform and controlling angle of attack. The three birds shared common spanwise patterns of wing twist, an inverse relationship between twist and peak camber, and held their wings depressed below their shoulder in an anhedral configuration. With increased speed, all three birds tended to reduce camber throughout the wing, and their wings bent in a saddle-shape pattern. A number of morphing features suggest that the coordinated movements of the wing and tail support efficient flight, and that the tail may act to modulate wing camber through indirect aeroelastic control.

E26 transformation‐specific (ETS) gene family contains a common DNA‐binding domain, the ETS domain, responsible for sequence‐specific DNA recognition on target promoters. The Fli‐1 oncogene, a member of ETS gene family, plays a critical role in hematopoiesis and is overexpressed in diverse hematological malignancies. This ETS transcription factor regulates genes controlling several hallmarks of cancer and thus represents an excellent target for cancer therapy. By screening compounds isolated from the medicinal plant Dysoxylum binectariferum in China, we identified two chemically related flavagline‐like compounds including 4′‐demethoxy‐3′,4′‐methylenedioxyrocaglaol and rocaglaol that strongly inhibited Fli‐1 transactivation ability. These compounds altered expression of Fli‐1 target genes including GATA1, EKLF, SHIP1, and BCL2. Consequently, the flavagline‐like compounds suppressed proliferation, induced apoptosis, and promoted erythroid differentiation of leukemic cells in culture. These compounds also suppressed erythroleukemogenesis in vivo in a Fli‐1‐driven mouse model. Mechanistically, the compounds blocked c‐Raf‐MEK‐MAPK/ERK signaling, reduced phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), and inhibited Fli‐1 protein synthesis. Consistent with its high expression in myelomas, B‐cell lymphoma, and B chronic lymphocytic leukemia (B‐CLL), pharmacological inhibition of Fli‐1 by the flavagline‐like compounds or genetic knock‐down via shRNA significantly hindered proliferation of corresponding cell lines and patients’ samples. These results uncover a critical role of Fli‐1 in growth and survival of various hematological malignancies and point to flavagline‐like agents as lead compounds for the development of anti‐Fli‐1 drugs to treat leukemias/lymphomas overexpressing Fli‐1.

Aerodynamic functions of the avian tail have been studied previously using observations of bird flight, physical models in wind tunnels, theoretical modelling and flow visualization. However, none of these approaches has provided rigorous, quantitative evidence concerning tail functions because (i) appropriate manipulation and controls cannot be achieved using live animals and (ii) the aerodynamic interplay between the wings and body challenges reductive theoretical or physical modelling approaches. Here, we have developed a comprehensive analytical drag model, calibrated by high-fidelity computational fluid dynamics (CFD), and used it to investigate the aerodynamic action of the tail by virtually manipulating its posture. The bird geometry used for CFD was reconstructed previously using stereo-photogrammetry of a freely gliding barn owl ( Tyto alba ) and we validated the CFD simulations against wake measurements. Using this CFD-calibrated drag model, we predicted the drag production for 16 gliding flights with a range of tail postures. These observed postures are set in the context of a wider parameter sweep of theoretical postures, where the tail spread and elevation angles were manipulated independently. The observed postures of our gliding bird corresponded to near minimal total drag.

A three-dimensional fluid–body interaction model was established to study the hydrodynamics of larval fish at a quick start with a turning angle of approximately 80°. The bending curves of the larval fish were attained by extracting the middle line of fish snapshots from a previously published paper. The fluid–body interaction was implemented to empower the self-propelling function of the larval fish. In this study, the swimmer’s kinematics of the body as well as hydrodynamics at preparatory and propulsive stages of the larval fish were extensively analysed. It shows that during the preparatory stage, the larval fish produces a significant force against the escaping direction. Nevertheless, this force leads to a large turning torque, helping to accomplish a quick turning. During the propulsive stage, the force increases quickly in the escape direction, resulting in a large velocity for the escape. The characteristics of body motion and the flow field are consistent with the previous observation on adult fish: the bimodal mode on velocity and tangential acceleration and three jets of fluids. In addition, the research also reveals that the forces generated at anterior and posterior parts of the larval fish generally point to the opposite directions at both preparatory and propulsive strokes of C-start.