This study reports the effect of liposome particle size at the nanoscale and bilayer deformability on the permeation through MatTek human skin equivalents and provides a comparative quantitative measure through calculation of diffusion coefficients. Exploring DOPC and DPPC fluorescent liposomes, our results demonstrate the faster diffusion of 50 nm liposomes compared with 100 and 200 nm liposomes when the lipid bilayer remains the same. Diffusion kinetics of the 50 nm particles appear not to depend on the rigidity of the lipid layer, whereas diffusion of particles larger than 100 nm is significantly affected by the rigidity of the bilayer, and DOPC liposomes diffuse faster than their DDPC equivalents. Our results suggest that liposomes composed of a rigid bilayer can be expected to remain intact after passing through the stratum corneum.

To predict very high cycle fatigue (VHCF) from data of standard monotonic tests the cumulative model of VHCF was elaborated. The model bases on the following assumptions: (1) Fatigue cracks are initiated, if the fraction of plastically dissipated energy corresponding to tensile stresses reaches the threshold; (2) This threshold is the constant for the given initial mechanical properties of alloys, if influence of the phase transformations on these properties is not significant, and the absolute temperatures of deformation are not above of temperatures of beginning recrystallization. The predicted values of VHCF for typical bearing, spring, stainless steels, and typical Ti‐ and Al‐alloys are in satisfied agreements with published values.

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