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The lipid membranes of living cells form an integral part of biological systems, and the mechanical properties of these membranes play an important role in biophysical investigations. One interesting problem to be evaluated is the effect of protein insertion in one leaflet of a bilayer on the physical properties of lipid membrane. In the present study, an all atom (fine-grained) molecular dynamics simulation is used to investigate the binding of cytotoxin A3 (CTX A3), a cytotoxin from snake venom, to a phosphatidylcholine lipid bilayer. Then, a 5-microsecond [corrected] coarse-grained molecular dynamics simulation is carried out to compute the pressure tensor, lateral pressure, surface tension, and first moment of lateral pressure in each monolayer. Our simulations reveal that the insertion of CTX A3 into one monolayer results in an asymmetrical change in the lateral pressure and corresponding spatial distribution of surface tension of the individual bilayer leaflets. The relative variation in the surface tension of the two monolayers as a result of a change in the contribution of the various intermolecular forces may potentially be expressed morphologically.

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The new types of bladeless wind turbines and generating electricity using them is one of the most interesting topics for engineering nowadays. Electricity generation using the structural vibration due the resonance phenomenon is the concept behind a vortex bladeless turbine. The present study numerically investigates the effects of the drag force on the body frequency of an oscillating bladeless wind turbine. A 2-D numerical simulation was performed for a cylinder with a semi-circular cross-section in cross-flow in two different cases. The research was conducted for both uncontrolled and controlled oscillating cylinders. The controlling process was performed using a pair of ring magnets as a spring with a variable coefficient. The flow field, vibration, vortex shedding and structural frequencies, and the resonance phenomenon are studied in this research. Finally, the controlled and uncontrolled frequencies of the cylinder are explored, and the power spectrum for various velocities is analyzed in two different states, namely with and without a tuning system. From the results, it can be concluded that the usage of the controlling system in these turbines can greatly regulate the oscillations and increase the frequency value by limiting the vibration amplitude. According to this principle, it can be inferred that increasing the frequency of fluctuations greatly increases the production capacity of these turbines.

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