Minoru Yoshimoto

Latex piezoelectric immunoassay: analysis of C-reactive protein in human serum

We constructed an integrated immunosensor system to combine a quartz crystal microbalance with the agglutination reaction of immunized latex beads. C-reactive protein (CRP) induced an immunoreaction due to the latex bends with anti-CRP antibody. We succeeded in determining the concentration of CRP necessary in human serum for disease diagnosis using a CRP Sensor I.

Asymmetric coupling stabilizes the out-of-phase mode : experimental evidence in the Belousov-Zhabotinsky reaction

Abstract The Belousov—Zhabotinsky reaction was studied for the system with two continuous-flow stirred tank reactors coupled to each other through mass transfer. The coupling strength was quantitatively controlled by changing the flow rate between the reactors with a peristaltic pump. It became clear that when the coupling between the reactors was symmetric, synchronization or entrainment with the in-phase mode was quite stable. On the other hand, the parameter space, or the basin, of the out-of-phase mode became greater with “asymmetric” coupling. Such an experimental trend is discussed in relation to the results of numerical simulations on coupled nonlinear differential equations.

Bromomalonic acid as a source of photochemically produced Br− ion in the Ru(bpy)32+-catalyzed Belousov-Zhabotinsky reaction

Abstract Experimental observation shows that bromomalonic acid (BrMA) is one of the sources of photo-induced Br− ion in the photosensitive Belousov-Zhabotinsky reaction. The rate of Br− production by visible light was measured using a Br−-ion-selective electrode in a solution containing BrMA, H2SO4 and Ru(bpy)3SO4 but no oxybromine species. The order of reaction was 1 for [BrMA] and [H+], and about 1 2 for the light intensity and [Ru(bpy)32+]. Two types of probable photocyclic mechanisms are proposed.

Phase-death mode in two-coupled chemical oscillators studied with reactors of different volume and by simulation

Abstract The behavior of the phase-death mode (cessation of oscillations and transition to a steady state) in the two-coupled Belousov–Zhabotinsky reactions is studied in the asymmetric coupling. In an experiment, the types of synchronized modes and their regions were investigated as an extension of our previous study. This experiment is compared to a simulation using the two-coupled three-variable Oregonator models. The results confirm that the phase-death mode changes from “bistable” to “monostable” and reveal the stable region of the latter.

Map-Based Analysis of Noise-Induced Convergence in Chaos

The mechanism and condition of appearance of order in chaos with Gaussian white noise is investigated based on the Poincare return map constructed from the three-variables ODE of the Belousov-Zhabotinsky reaction. When the noise is added to the chaos having the bifurcation parameter near period-three oscillation, it occasionally happens that topological entropy is constant but the Kolmogorov entropy decreases. Analysis on three-times iterated map reveals that this phenomenon, named “noise-induced convergence”, is caused by an increase of the length of laminar phase and the subsequent change of the invariant density. The same phenomenon is observed in m-times iterated map of the chaos of the logistic map. We consider that “noise-induced convergence” is characteristic of intermittent chaos.

Effect of Noise on Chaos in a One-Dimensional Map

The mechanism and the characteristics of appearance of order in chaos with Gaussian white noise are investigated in the logistic map. This order (noise-induced order) appears as the constancy of the topological entropy and the decrease of the Kolmogorov entropy. Analysis of n-times iterated map reveals that “noise-induced order” is caused by the increase of the length of the laminar region and the subsequent change of the invariant density, where “local structure” overcomes “global structure”. We find that “noise-induced order” is accelerated by an increase of the noise period, and takes place only in chaos near period-five and -under windows.

Effect of Noise on the Low Flow Rate Chaos in the Belousov-Zhabotinsky Reaction

We investigate systematically the effect of Gaussian white noise (type P noise) on the low flow rate chaos in both systems far from and close to bifurcation points using the three-variables ODE of the Belousov-Zhabotinsky reaction developed by Gyorgyi and Field. When the noise is added to the chaos with the bifurcation parameter far from bifurcation points, the chaos trajectories are slightly scattered. However, in the chaos having the bifurcation parameter near bifurcation points, it happens that topological entropy is constant but the Lyapunov exponent decreases. We have found that this phenomenon, named “noise-induced order”, appears in intermittent chaos with the internal structure of m -periodic oscillation, and that “noise-induced order” is caused by an increase in the length of laminar region and the subsequent change of the invariant density.

Effect of Noise on the High Flow Rate Chaos of the Belousov-Zhabotinsky Reaction

We systematically investigated the effect of Gaussian white noise on the high flow rate chaos of the Belousov–Zhabotinsky reaction in both the systems far from and close to a bifurcation point. Whe...

Effect of Zwitterionic Detergent on the Solution Viscosity and Density in the Belousov-Zhabotinsky Reaction

Minoru Yoshimoto,1 Shingo Kubo,1 and Shigeru Kurosawa2 Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba West, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan (Received April 6, 2015; Revised July 17, 2015)

Effect of Polyoxyethylene (10) Octylphenyl Ether on the Solution Viscosity and Density in the Belousov-Zhabotinsky Reaction

We investigated the dynamical behavior between the redox potential and the viscosity and density of the Belousov-Zhabotinsky (BZ) reaction by the systematic variation of the mixing level and the solution viscosity and density. The mixing level was controlled by the stirrer bar speed, and the solution viscosity and density was changed by the addition of polyoxyethylene (10) octylphenyl ether (Triton X-100). This study has revealed that three types of oscillations with phase difference appear, depending on the mixing level and the solution viscosity and density of the BZ reaction. It has also become clear that the critical micellization concentration (cmc) plays an important role in the behavior of the oscillation of the solution viscosity and density.