Abstract: A manufacturing process of a microstructured optical fiber including a void-containing region, includes the steps of: drawing a microstructured optical fiber along a longitudinal direction from a heated preform, wherein the optical fiber is continuously advanced along the longitudinal direction; directing a radiation beam at a longitudinal position in the longitudinal direction of the optical fiber so as to produce an interference pattern; detecting the interference pattern and producing at least one electrical detection signal corresponding to the interference pattern and including a plurality of signal fringe cycles; feeding the first detection signal into a first counter circuit; determining a first number of interference fringe increments in the plurality of signal wave fringe cycles of the at least one detection signal by using the first counter circuit; determining the outer diameter of the optical fiber, and controlling the microstructure of the optical fiber during advancement of the optical fiber.

Abstract: A manufacturing process of a microstructured optical fibre including a void-containing region, includes the steps of: drawing a microstructured optical fibre along a longitudinal direction from a heated preform, wherein the optical fibre is continuously advanced along the longitudinal direction; directing a radiation beam at a longitudinal position in the longitudinal direction of the optical fibre so as to produce an interference pattern; detecting the interference pattern and producing at least one electrical detection signal corresponding to the interference pattern and including a plurality of signal fringe cycles; feeding the first detection signal into a first counter circuit; determining a first number of interference fringe increments in the plurality of signal wave fringe cycles of the at least one detection signal by using the first counter circuit; determining the outer diameter of the optical fibre, and controlling the microstructure of the optical fibre during advancement of the optical fibre.

Abstract: There are provided compounds I ##STR1## wherein A is a hydrogen atom or an organic group,R.sub.1 is hydrogen or halogen atom or an organic group,R.sub.2 is hydrogen or halogen atom, C.sub.1 -C.sub.4 alkyl or acyloxy group,R.sub.3 is hydrogen atom, C.sub.1 -C.sub.4 alkyl or alkoxy, benzyl group or a methylene andR.sub.4 is chloro, fluoro, hydrogen atom or an organic group.The compounds I are elastase inhibitors. A process for their preparation is also provided, as are pharmaceutical compositions containing them.