Silicone adhesive multilayer foam dressings as adjuvant prophylactic therapy to prevent hospital-acquired pressure ulcers: a pragmatic noncommercial multicentre randomized open-label parallel-group medical device trial.

Background: Silicone adhesive multilayer foam dressings are used as adjuvant therapy to prevent hospital-acquired pressure ulcers (PUs).

Objectives: To determine whether silicone foam dressings in addition to standard prevention reduce the incidence of PUs of category 2 or worse compared with standard prevention alone.

Methods: This was a multicentre, randomized controlled medical device trial conducted in eight Belgian hospitals.

Confinement-induced liquid ordering investigated by x-ray phase retrieval.

Using synchrotron x-ray diffraction, we have determined the ensemble-averaged density profile of colloidal fluids within confining channels of different widths. We observe an oscillatory ordering-disordering behavior of the colloidal particles as a function of the channel width, while the colloidal solution remains in the liquid state. This phenomenon has been suggested by surface force studies of hard-sphere fluids and also theoretically predicted, but here we see it by direct measurements of the structure for comparable systems.

X-ray diffraction method for the investigation of contacts between solid surfaces.

A coherent X-ray scattering method for investigating the formation of the contact region between two solid surfaces is presented. Diffraction of X-rays from two crossed cylindrical quartz surfaces, coated with Cr and TiO(2), revealed a total contact area of 90 +/- 10 microm. In the so-called Hertz model for two surfaces in non-adhesive contact, this value is directly related to the displacement of the surfaces and the applied external force.

How do smectic liquid crystals of different molecular length mix in thin films?

We present a model for the structure of binary mixtures of smectic compounds in freely suspended films of 2-7 layers. The compounds are the hexyl (6AB) and dodecyl (10AB) homologues of p, p'-dialkylazoxybenzene that differ by about 40% in molecular length. X-ray reflectivity indicates that no demixing occurs between 6AB and 10AB molecules, while also there is no indication found of increased roughness at the film surfaces.