Incorporation of silicone oil into elastomers enhances barnacle detachment by active surface strain.

Silicone-oil additives are often used in fouling-release silicone coatings to reduce the adhesion strength of barnacles and other biofouling organisms. This study follows on from a recently reported active approach to detach barnacles, which was based on the surface strain of elastomeric materials, by investigating a new, dual-action approach to barnacle detachment using Ecoflex®-based elastomers incorporated with poly(dimethylsiloxane)-based oil additives. The experimental results support the hypothesis that silicone-oil additives reduce the amount of substratum strain required to detach barnacles. The study also de-coupled the two effects of silicone oils (ie surface-activity and alteration of the bulk modulus) and examined their contributions in reducing barnacle adhesion strength. Further, a finite element model based on fracture mechanics was employed to qualitatively understand the effects of surface strain and substratum modulus on barnacle adhesion strength. The study demonstrates that dynamic substratum deformation of elastomers with silicone-oil additives provides a bifunctional approach towards management of biofouling by barnacles.

Endothelial colony forming cells (ECFCs) as a model for studying effects of low-dose ionizing radiation: growth inhibition by a single dose.

Identification of measurable nontransient responses to low-dose radiation in human primary cell cultures remains a problem. To this end, circulating endothelial colony-forming (progenitor) cells (ECFCs) were examined as an experimental model. ECFCs were isolated from three cord blood donors. Cells were positive for endothelial cell markers and remained highly proliferative after long-term cryopreservation. A single dose of X-ray radiation (0.06-0.38 Gy) inhibited ECFC culture growth. This effect was evident at 48 hours and persisted up to 72 hr postirradiation. Such protracted cytostatic response of ECFCs to low-dose radiation suggests that ECFC primary cultures can be used to study low-dose radiation effects.