Cell membrane tensile strain under cyclic compression:A viscoelastic myoblast finite element model

Cyclic mechanical stimulation could lead to subsequent biomechanical and biological effects on cells.Viscoelastic cells could deform or show energy dissipation with hysteresis behavior in response to external cyclic compression.The aim of this study was to investigate the effect of cyclic compression on a single viscoelastic myoblast through a confocal–based cell–specific finite element model,including cell membrane tensile strain and damaged elements.Sinusoidal compression was applied to the apical surface of the myoblast(cell membrane)with compressive stress of 500
500 Pa(with stress offset at 500 Pa and amplitude of 500 Pa)at 0 Hz(static compression of 500 Pa),0.25 Hz,0.5 Hz,0.75 Hz,1 Hz,5 Hz,and 10 Hz.Results showed that the ratio of average tensile strain integral in all cell membrane elements over a certain period of time(T)to that duration(T)(MAS index)decreased under cyclic compression compared to that of static compression in the short term(within 4 s).Furthermore,compared to static compression,the percentage of damaged elements of cell membrane under cyclic compression decreased assuming a 3%cell membrane tensile strain damage threshold.The optimal cyclic compression frequency 0.25 Hz led to the largest difference of MAS index under cyclic compression and static compression.These results may provide support for the application of cyclic compressive stimulation in the prevention of cell damage.

Data-driven placemaking: Public space canopy design through multi-objective optimisation considering shading, structural and social performance

In the context of ongoing densification of cities and aging urban populations,public spaces are a crucial infrastructure to support the physical and mental wellbeing of urban residents.The design of public space furniture elements is often standardised,and not considered in relation to environmental conditions and mechanisms of social interaction.This article presents a digital workflow to generate site-specific designs for shaded public seating,considering the relationships of local public places to their surroundings.A strategy for customised and site-specific design is developed through the use of multiple software tools,employing evolutionary algorithms and multi-objective optimisation.The method is applied to a small public space canopy prototype installed within a public housing estate in Hong Kong,incorporating additional criteria to achieve a low-cost and light-weight structure.Through multiple stages of refinement and optimisation,a material,structural and social performance-driven outcome was achieved that creates a shaded space for public seating,people watching and social interaction.As part of a larger research agenda exploring architectural form-finding and environmental psychology,the project represents potential new applications in the emerging field of socially driven computational design.