In vivo friction study of human skin: Influence of moisturizers on different anatomical sites

In order to understand the human haptic system, the mechanical characterization of skin contact is an important task. As the skin constitutes itself a surface, it is convenient to describe the problem using a contacting surface analysis, especially concerning the friction which occurs when the skin interacts with other surfaces. Several published works have shown that the analysis of the friction response of the skin can provide an indirect way to assess the skin condition.http://www.sciencedirect.com/science/article/B6V5B-4NT57HS-3W/1/d4ae2f1e00e46a09d2bc88be50b2a94

Simulation of polyelectrolyte solutions. The density of bound ions

We discuss a simple approach to describe the ion density around a polyelectrolyte chain, quantifying bound and bulk counterions, and allowing for the renormalization of the charge in the polyion. This approach is both physically motivated and readily extensible to systems containing other types of highly charged ions. The method addresses the problem in simulation experiments and allows to correlate ion condensation and compaction.http://www.sciencedirect.com/science/article/B6TFN-4DGDCY6-9/1/14f30c4cf6f0da32c52c85dc2c18897

Comparison of dissolution profiles of Ibuprofen pellets

In this work we use both model dependent and independent techniques to assess the difference between dissolution profiles in which ibuprofen, in the form of uncoated pellets, is used as a model drug. The choice of a proper regression function, the relevance of the estimated parameters and the influence of the choice of dissolution points in the assessment of differences is discussed. The results obtained via mean dissolution times (MDT) and fit-factors (f1 and f2) are also discussed and a non-quantitative method based on profiles correlation with graphical representation (concentration vs. concentration and rate vs. rate) presented. The tested methods discriminate similarly between curves, although not in all cases, but those based on modeling, MDT and fit-factors have shown to be less informative than the correlation approach.http://www.sciencedirect.com/science/article/B6T3D-48CT09D-6/1/963a3879961981b265df020d3ac842f

Science indicators and science patterns in Europe

http://www.sciencedirect.com/science/article/B83WV-4VK69B2-1/2/857bd537a0546fe2cb394c525b44341

Stratum corneum hydration: Phase transformations and mobility in stratum corneum, extracted lipids and isolated corneocytes

The outermost layer of skin, stratum corneum (SC), functions as the major barrier to diffusion. SC has the architecture of dead keratin filled cells embedded in a lipid matrix. This work presents a detailed study of the hydration process in extracted SC lipids, isolated corneocytes and intact SC. Using isothermal sorption microcalorimetry and relaxation and wideline 1H NMR, we study these systems at varying degrees of hydration/relative humidities (RH) at 25 °C. The basic findings are (i) there is a substantial swelling both of SC lipids, the corneocytes and the intact SC at high RH. At low RHs corneocytes take up more water than SC lipids do, while at high RHs swelling of SC lipids is more pronounced than that of corneocytes. (ii) Lipids in a fluid state are present in both extracted SC lipids and in the intact SC. (iii) The fraction of fluid lipids is lower at 1.4% water content than at 15% but remains virtually constant as the water content is further increased. (iv) Three exothermic phase transitions are detected in the SC lipids at RH = 91-94%, and we speculate that the lipid re-organization is responsible for the hydration-induced variations in SC permeability. (v) The hydration causes swelling in the corneocytes, while it does not affect the mobility of solid components (keratin filaments).http://www.sciencedirect.com/science/article/B6T1T-4NYSXNX-1/1/13ceda49278be1653e6556cd65cb3ef

The intersecting-state model: a link between molecular spectroscopy and chemical reactivity

The intersecting-state model is applied to calculate the energy barriers and rates of atom transfers, SN2 reactions, proton transfers and electron transfers, including electron transfer at the metal-electrolyte interface. The calculated rates are usually within one order of magnitude of the experimental ones. These applications of the model reveal the main factors that influence the rates of these chemical reactions. The structural and electronic properties of reactants that are used in the calculations are the reaction energy, the hypervalency at the transition state, the bond lengths and for constants of the reactive bonds.http://www.sciencedirect.com/science/article/B6TGS-435M5SD-3/1/77dc7dce5b87eab97a0480c42652da0