[The epidermal barrier]. / Barrière épidermique.

The skin acts as an interface between the body and its surrounding environment. The epidermis, the surface layer of the skin, is chiefly responsible for this interactive protective function. The epidermal barrier may be subdivided into three defensive systems: the photoprotective barrier, the immune barrier, and the physical and chemical barrier of the stratum corneum or horny layer. To protect against harmful ultraviolet radiation, the epidermis has absorption factors such as melanin, produced by melanocytes, and urocanic acid, which is a degradation product of filaggrin. The epidermal immune defence system comprises an innate component, which is rapid but non-specific, together with adaptive response, which is systemic and antigen-specific, initiated by Langerhans cells. The stratum corneum, derived from terminal differentiation of epidermal keratinocytes, plays a key role as a physical and chemical permeability barrier. This horny layer is made up of corneocytes, covered with horny envelopes and linked to one another by corneodesmosomes and by extracellular matrix sheets. The epidermal barrier, which is constantly being renewed, is characterised by its extremely great capacity of adaptation to changing conditions in the environment.

Aqueous dispersions of organogel nanoparticles - potential systems for cosmetic and dermo-cosmetic applications.

OBJECTIVE: The preparation and physicochemical characterization of organogel nanoparticles dispersed in water have been developed. These systems could be employed as nanocarrier for cosmetic applications or as hydrophobic reservoirs for drug delivery. METHODS: Gelled particles of organic liquid and 12-hydroxystearic acid (organogelator) were obtained by hot emulsification (T>Tgel), with a surfactant (acetylated glycol stearate) and polymers (sodium hyaluronate and polyvinyl alcohol) as stabilizing agents, and cooling at room temperature (T

Olive pulp and its effluents suitability for soil amendment.

Olive pulp (OP) and its effluents produced after digestion processes were characterised and their suitability as soil amendment materials were investigated. Results showed that OP and its effluent for hydrogen (EH2) and methane production (ECH4) contain high amount of organic matter, remarkable concentration of nutrients and negligible content of heavy metals. Decreasing concentrations of low molecular weight phenols (monomeric phenols) and increasing amount of humic-like materials were found passing from OP to EH2 and ECH4. The effects on both wheat seed germination and seedlings growth were also investigated. Addition of OP at the highest doses delayed both seed germination and seedling growth. These effects decreased when the OP and its effluents were incorporated into the soil. On the contrary an enhancement of seedlings growth was detected by addition of EH2 and ECH4. Enhancement effects also were found out by addition of lower OP concentrations. The phytotoxic effects decreased when the products were incorporated into the soil.