Skin, mechanics

Kupper TS. Fuhlbrigge RC Immune surveillance in the skin mechanisms and clinical consequences. Nat Rev Immunol 2004 4 211-222. 

Thermoplastic structural foams with bulk densities not less than 50% of the solid resin densities are considered. Cellular morphology, uniform-density cell behaviour, the I-beam concept in designing, core-density profile and the role of the skin, mechanical properties, and ductile-brittle transitions are discussed. 63 refs. 

Coutts, A.A., Jorizzo, J.L., Eady, R.A.J., Greaves, M.W., Burnstock G. Adenosine triphosphate-evoked vascular changes in human skin mechanism of action, Eur. J. Pharmacol. 1981, 76, 391-401. 

The epidermis plays a role in skin mechanics. Thereby, hydrophilic as well as hydrophobic substances affect mechanical properties of the skin. Changes in skin mechanics can be the result of either a direct influence of a substance on the intercellular matrix, or an epiphenomenona, for example, a physiological shift of water between the tissues aimed to maintain physiological homeostasis, 50 The hydration level of the SC affects its mechanical properties. Increased hydration of the SC influences its extensibility and elasticity.51-54 Examples from human diseases such as ichthyotic and xerotic disorders indicate that thickening of the SC due to hyperkeratosis and increased corneocyte cohesion is responsible for a marked decrease in the flexibility of the entire SC.55... 

Overgaard Olsen, L. and Jemec, G.B. The influence of water, glycerin, paraffin oil and ethanol on skin mechanics. Acta Derm. Venereol. 1993,73 404-6. 

Jemec, G.B. and Serup, J. Epidermal hydration and skin mechanics. The relationship between electrical capacitance and the mechanical properties of human skin in vivo. Acta Derm. Venereol. 1990,70 245-7. 

Friction is an important characteristic of skin because it allows us to execute many of our daily activities. In addition, friction studies offer insight into how skin and the skin surface change across age, gender, race, anatomical site, and chemical applications. This can provide better information about expected skin variations in the population and why certain topical applications are effective. Comparative studies are particularly useful in following how the skin mechanically changes under different conditions. 

Gniadecka M, Ginadecki R, Serup J, Sondergaard J. Skin mechanical properties present adaptation to man s upright position. Acta Derm Venereol. 1994 74 188-190. 

Kim, Y. H., Ghanem, A. H., Mahmoud, H. and Higuchi, W. I. (1992a). Short-chain alkanols as transport enhancers for lipophilic and polar/ionic permeants in hairless mouse skin Mechanism(s) of action. nt. J. Pharm. 80 17-31. 

The present summary will cover only those technologies where the drug formulation itself is used to penetrate the skin via its mechanical energy. It will not describe any technology where a needle is used to puncture the skin, even if the needle is not visible to the patient or only the epidermis is punctured, such as mini-needles, microneedles, pen injectors, or autoinjectors. Also excluded are systems that ablate the skin mechanically or otherwise disrupt its chemical or mechanical structure to increase its permeability, such as laser ablation, microdermal ablation, electroporation, or iontophoresis. These are usually referred to as transdermal drug delivery, but can also be described as needle free. 

Prausnitz, M.R. Bose, V. Langer, R. Weaver, J.C. Electroporation of mammalian skin mechanism to enhance transdermal drug delivery. Proc. Natl. Acad. Sci. 1993, 90, 10504-10508. 

G Primaveia, E Beiatdesca, Sensitive skin mechanisms and diagnosis Int. J. Cosm. Set. 2005 271-10. 

Barel A. O., W. Courage and P. Clarys, 1995, Suction Method for Measurement of Skin Mechanical Proprietes, The Cutometer in Handbook of Non-lnvasive Methods of the Skin, Eds. J. Semp and G. B. E. Jemec, CRC Press, Boca Raton. 

Toxicology Non-irritating to skin mechanical eye irritant TSCA listed Precaution Wear safety glasses, chemical resistant gloves, NIOSH approved dust mask sensitive to static electricity Hazardous Decomp. Prods. CO, COj, nitrogen, water HMIS Health 1, Flammability 1, Reactivity 0 Storage Store ambient temps. 

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