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Argatov I, Engblom J, Kocherbitov V. Modeling of composite sorption isotherm for stratum corneum. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183910. [PMID: 35300950 DOI: 10.1016/j.bbamem.2022.183910] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/18/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
Equilibrium water sorption in stratum corneum (SC) is considered by treating it as a biocomposite with two main phases, namely, corneocytes and lipids. To validate the rule of mixtures for the individual phase sorption isotherms, a new flexible fitting model is introduced by accounting for characteristic features observed in the variations of the thermodynamic correction factors corresponding to the individual sorption isotherms. The comparison of the model fitting performance with that of the five-parameter Park's model shows a remarkably good ability to fit experimental data for different types of sorption isotherms. The effect of the lipids content on the variance of the composite sorption isotherm of stratum corneum is highlighted. The sensitivity analysis reveals that for the typical water content 20-30 wt%, which corresponds to the SC in a stable condition, the sensitivity of the composite sorption isotherm to the variation of the lipids content on dry basis is predominantly positive and sufficiently small. The good agreement observed between the experimental sorption isotherm for SC and the composite isotherm, which is based on the rule of mixtures for the individual phase sorption isotherms, yields a plausible conclusion (hypothesis) that the corneocytes-lipids mechanical interaction during unconstrained swelling of the SC membrane in the in vitro laboratory experiment is negligible.
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Affiliation(s)
- Ivan Argatov
- Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden; Institut für Mechanik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Johan Engblom
- Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Vitaly Kocherbitov
- Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
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Choi C, Ma Y, Li X, Chatterjee S, Sequeira S, Friesen RF, Felts JR, Hipwell MC. Surface haptic rendering of virtual shapes through change in surface temperature. Sci Robot 2022; 7:eabl4543. [PMID: 35196072 DOI: 10.1126/scirobotics.abl4543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Compared to relatively mature audio and video human-machine interfaces, providing accurate and immersive touch sensation remains a challenge owing to the substantial mechanical and neurophysical complexity of touch. Touch sensations during relative lateral motion between a skin-screen interface are largely dictated by interfacial friction, so controlling interfacial friction has the potential for realistic mimicry of surface texture, shape, and material composition. In this work, we show a large modulation of finger friction by locally changing surface temperature. Experiments showed that finger friction can be increased by ~50% with a surface temperature increase from 23° to 42°C, which was attributed to the temperature dependence of the viscoelasticity and the moisture level of human skin. Rendering virtual features, including zoning and bump(s), without thermal perception was further demonstrated with surface temperature modulation. This method of modulating finger friction has potential applications in gaming, virtual and augmented reality, and touchscreen human-machine interaction.
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Affiliation(s)
- Changhyun Choi
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Yuan Ma
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA.,Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, P. R. China.,Research Institute for Intelligent Wearable Systems, The Hong Kong Polytechnic University, Hong Kong, P. R. China
| | - Xinyi Li
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Sitangshu Chatterjee
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Sneha Sequeira
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Rebecca F Friesen
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Jonathan R Felts
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - M Cynthia Hipwell
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
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