PMC

Ejection mechanisms of a fungal cannon (E. muscae s. str.) and the soft water cannon (elastomeric tube). (a) SEM picture of conidiophores of the fungus E. muscae s. str. The tip of each cell differentiates into a conidium bounded by a septum (indicated in c). Scale bar, 20 µm. Inset: fly with distinctive white/yellowish bands of fungal conidiophores. (b) High-speed videography (15 000 fps) of the ejection of a conidium (solid blue trace) from its conidiophore (dotted grey trace) at the rupture line (red trace) just below the septum. Protoplasm (dotted white trace) is observed as a small satellite drop and a second liquid drop remaining attached to the conidiophore. Scale bar, 20 µm. (c) Mechanism of ejection for (top left, scale bar, 10 µm) the fungal cannon and (top right, scale bar, 1 mm) the soft water cannon. Bottom: the spore or projectile (blue) is released from the cannon (grey) with velocity v₀ when the increasing pressure p overcomes the restoring force; the fungal cannon has elastic line force F_el while the soft water cannon has contact friction force . (Online version in colour.)

a) Chest roentgenogram showing multiple cannon ball shadows; b) Computed tomography scan of chest with lung window settings showing multiple nodules consistent with cannon ball metastases.

Cannon wave (arrow) in a 52-year-old woman with palpitations.

Chest x-ray showing multiple large ‘cannon ball’ pulmonary nodules.