Characterizing persistence and pause dynamical behaviors in biological systems

This paper analyzed motion that randomly switches between the persistent motion runs and pause periods. A two-state continuous-time Markov chain is used to model the motion, which led to a system with coupled differential equations. Using a combined Fourier–Laplace transform, an analytical expression for calculating the mean-squared displacement is derived. The overall motion is investigated and identified from the obtained mean-squared displacement. The mean-squared displacement is a nonlinear function in time that is dependent on the phase transition rate, the direction switching rate, the average speed, and the initial state. It decays and grows with increasing the direction switching and average speed, respectively. The effective diffusivity descents exponentially in short times and remains constant in long times. The waiting time in each phase decayed exponentially. The probability density function for the position of a particle at a given time tends to be Gaussian in long times. The motion can be interpreted as a super-diffusion in short times and a standard diffusion in long times with a diffusion coefficient dependent on the phase transition rates, the direction switching rate and the average speed. Persistence influences the dynamical behavior for short times while for long times diffusive behavior is exhibited.

Bioinspired DNA Origami Quasi-Yagi Helical Antenna with Beam Direction and Beamwidth Switching Capability

We propose a bioinspired origami quasi-Yagi helical antenna with beam direction and beamwidth switching capability based on transformable DNA origami structure. Each DNA molecule consists of a double helical chain, and its length can be transformed by folding and unfolding. When three transformable origami DNA structures are applied to the quasi-Yagi helical antenna, beam direction and beamwidth can be controlled by folding and unfolding the origami DNA. The transformable DNA structures act as driven, director and reflector elements. The proposed DNA origami antenna provides four beam direction switching states (three states with narrow beamwidth and one state with wide beamwidth) at fixed frequency of 1.9 GHz. For example, the main beam direction of the proposed antenna can be steered to −30°, 0°, +30° and −40° for states 1, 2, 3 and 4, respectively. State 4 provides a 3-dB wider beamwidth of 104°, whereas the beamwidth of other states is narrower than 64°. The proposed concept is numerically and experimentally demonstrated.

Photocurrent Switching on Electrophoretic CdSe QD Electrodes with Different Ligands

Photoelectrochemical behavior of oleate- and sulfide-capped CdSe QD films fabricated via electrophoretic deposition has been investigated in Na2SO3 aqueous electrolyte. The oleate substitution for sulfide led to considerable increase in photocurrent efficiency. Films of the both types show photocurrent switching under 465-nm light irradiation. The photocurrent direction switching potential strongly depends on the particle size demonstrating negative shift of the potential with size: from 0.0[Formula: see text]V for 2.4[Formula: see text]nm to [Formula: see text][Formula: see text]V for 6.3[Formula: see text]nm.

A sensitive photoelectrochemical assay of miRNA-155 based on a CdSe QDs//NPC-ZnO polyhedra photocurrent-direction switching system and target-triggered strand displacement amplification strategy

A new photoelectrochemical biosensor based on a CdSe QD//NPC-ZnO polyhedra photocurrent-direction switching system and a target-triggered strand displacement amplification strategy was developed for the detection of miRNA-155.