Abstract: The invention relates to piping for use as a pyrolysis tube in a cracking furnace. The tube is formed such that it has at least one section whose centreline curves in three dimensions, to induce swirl flow in the tube. Preferably, the tube is formed as a helix, more preferably a low-amplitude helix. The invention also extends to various other uses of piping with low-amplitude helical geometry.

Abstract: Tubing or piping for carrying a multiphase flow is provided with means for inducing swirl flow, such that the denser components of the flow tend to the outer wall of the tubing or piping, and less dense components tend to the center of the tubing or piping. The flow thus exhibits a “centrifuge” effect, which prevents lighter or heavier components of the flow from accumulating in upper or lower regions respectively of the tubing or piping, and reduces the risk of airlocks and the like. Preferably, the tubing or piping is in the form of a helix, which may be a low amplitude helix.

Abstract: A stent for insertion in a fluid conduit of a human or animal body when the stent is in a collapsed condition and for expansion to an expanded condition, includes an outer wall for engagement with the conduit. The outer wall has a helical portion which in the expanded condition extends longitudinally and circumferentially, and which, upon expansion of the stent from the collapsed condition to the expanded condition, resists extension.

Abstract: Aqueous formulations suitable for intranasal administration comprise buprenorphine or a physiologically acceptable salt or ester thereof and (a) a pectin having a degree of esterification of less than 50%, (b) chitosan and a polyoxyethylene-polyoxypropylene copolymer (poloxamer) or (c) chitosan and hydroxypropylmethylcellulose. Such formulations can induce rapid and prolonged analgesia when delivered intranasally to a patient. The buprenorphine or buprenorphine salt or ester may be delivered to the bloodstream to produce within 30 minutes a therapeutic plasma concentration of buprenorphine, Cther, of 0.2 ng/ml or greater which is maintained for a duration Tmaint of at least 2 hours.