Permeation Of Chemicals Research Articles

Permeability characteristics of the human nail plate

Synopsis The permeation of chemicals across the nail plate and their consequent effects are discussed in relation to cosmetic toxicity and possible clinical efficacy. The reviewed data are then assessed and placed in context with recent observations on the direct assessment of permeability of the human nail plate. Although marked differences between the diffusional barrier characteristics of nail and stratum corneum are shown, a reasonably unified picture of nail plate permeability is drawn from the collective observations. The cosmetic and clinical implications of chemical penetration of the nail plate are briefly outlined and places where knowledge needs to be strengthened are identified.

Kinetic considerations of the permeation of organic vapours through a flexible packaging film

SummaryA new method is presented for measuring the rates of permeation of organic vapours through flexible packing films with the specific intent of studying flavour deterioration from packaged foodstuffs. The method is convenient, relatively rapid, quantitative and the results are presented as first order rate constants for the permeation of individual chemicals through a film. This allows ready calculation of such potentially useful data as the temperature effects on permeation rates, the half‐life of retention of a vapour by a film barrier or the energy necessary for permeation through a particular film. As an example of the method, data for the permeation of eight organic compounds through 50 μm polyethylene film over the temperature range ‐25°C to +35°C are given as well as the half‐lives of retention of these compounds and the permeation energies required. The permeability constants may also be readily calculated from the rate data.

Importance of skin temperature in the regulation of sweating.

Human sweating regulation at rest, evaluating thermal inputs effects on thermoregulatory center and internal hypothalamic and skin temperatures