Abstract: There is disclosed a wound dressing comprised by an assembly of microfungal fibres which have been treated with alkali to expose chitin and chitosan. The fibres may be derived from hyphae or from sporangiophores. The assembly may include other fibres, may be bleached and incorporate other additives such as silver as an anti-bacterial agent.

Abstract: A knife of the kind having a blade (14, 43) and a handle has an extendible and retractable blade edge guard (16, 45). When the blade (14, 43) is extended, any violent movement of the knife with the cutting edge in a leading attitude acts inertially to disengage a detent (27, 55) from a recess (28, 57) in the guard (16, 45) so that a tension spring (17, 46) quickly extends the guard (16, 45) into its projecting, operative position to guard the blade edge (21, 50) and prevent at least serious injury. When the blade carrier (13, 42) is fully retracted, its engagement with a part (31, 58) of the guard (16, 45) causes that also to retract and be engaged again by the detent (27, 55) due to spring-bias.

Abstract: There is disclosed a method and apparatus for exchanging heat between a first fluid and a second fluid immiscible with said first fluid comprising the step of presenting one of said fluids in finely divided form for direct contact with the others. One fluid may be a molten metal which is sprayed or bubbled through the other.

Abstract: There is provided a knife having a blade and handle. The knife incorporates acceleration detection means adapted to cause automatic occlusion of the blade upon detection of violent movement of the knife of at least 25 meters per second per second.

Abstract: Clothing weatherproofed by being coated with plastics material of low permeability to water vapor is uncomfortable to wear.The present invention provides a breathable polyurethane film for coating on fabrics to make them waterproof. The film comprises a hard segment formed by reaction of a low molecular weight difunctional compound with excess diisocyanate to form a prepolymer and a soft segment provided by polyethylene glycol with which the prepolymer is reacted in a stoichiometric amount. If desired the film can be formed by reacting the polyethylene glycol with excess diisocyanate to form a prepolymer which is then reacted with a stoichiometric amount of a low molecular weight difunctional compound. The mechanical properties of the film can be improved by cross linking with a cross linking agent such as a triisocyanate.