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Zhonghuai Hou

Publications and source records attributed to Zhonghuai Hou.

At least 19 recordsLinked to original sources
PubMed2006

Engineered internal noise stochastic resonator in gene network: a model study.

Based on a genetic bistable switch model coupled with a gene oscillator model, we have constructed a mesoscopic stochastic model for the coupled synthetic gene network, and studied how internal noise would influence the oscillation of such a system. We found that the state-to-state transitions can occur if the internal noise is taken into account, and the performance of resulting oscillation can reach a maximum in a certain internal noise level, which indicates the occurrence of internal noise stochastic resonance (SR) and makes the coupled gene network work as a stochastic resonator. The potential role of such an effect on gene expression systems is also discussed.

Biological Clocks↗
PubMed2006

Two system-size-resonance behaviors for calcium signaling: for optimal cell size and for optimal network size.

We have studied the collective calcium signaling behavior of an array of coupled N cells, taking into account the internal noises resulting from the small cell size V. The system's performance was characterized by the reciprocal coefficient of variance (RCV) of the calcium spike train. Two system-size resonances were observed, namely, the RCV value shows a clear peak when both N and V are optimal. Therefore, an optimal number of cells of optimal size work the best as a whole.

Animals↗
PubMed2006

Internal noise coherent resonance for mesoscopic chemical oscillations: a fundamental study.

The effect of internal noise for a mesoscopic chemical oscillator is studied analytically in a parameter region outside, but close to, the supercritical Hopf bifurcation. By normal form calculation and a stochastic averaging procedure, we obtain stochastic differential equations for the oscillation amplitude r and phase theta that is solvable. Noise-induced oscillation and internal noise coherent resonance, which has been observed in many numerical experiments, are reproduced well by the theory.

Journal Article↗
PubMed2006

Ordering spatiotemporal chaos in complex thermosensitive neuron networks.

We have studied the effect of random long-range connections in chaotic thermosensitive neuron networks with each neuron being capable of exhibiting diverse bursting behaviors, and found stochastic synchronization and optimal spatiotemporal patterns. For a given coupling strength, the chaotic burst-firings of the neurons become more and more synchronized as the number of random connections (or randomness) is increased and, rather, the most pronounced spatiotemporal pattern appears for an optimal randomness. As the coupling strength is increased, the optimal randomness shifts towards a smaller strength. This result shows that random long-range connections can tame the chaos in the neural networks and make the neurons more effectively reach synchronization. Since the model studied can be used to account for hypothalamic neurons of dogfish, catfish, etc., this result may reflect the significant role of random connections in transferring biological information.

Journal Article↗
PubMed2006

Frequency-selective response of FitzHugh-Nagumo neuron networks via changing random edges.

We consider a network of FitzHugh-Nagumo neurons; each neuron is subjected to a subthreshold periodic signal and independent Gaussian white noise. The firing pattern of the mean field changes from an internal-scale dominant pattern to an external-scale dominant one when more and more edges are added into the network. We find numerically that (a) this transition is more sensitive to random edges than to regular edges, and (b) there is a saturation length for random edges beyond which the transition is no longer sharpened. The influence of network size is also investigated.

Action Potentials↗
PubMed2005

Canard explosion and coherent biresonance in the rate oscillation of CO oxidation on platinum surface.

The relationship between canard explosion and coherent biresonance is analyzed by numerically investigating a temporal dynamical model of CO oxidation on Pt surface. Canard explosion, manifesting itself by a dramatic change in the amplitude and period of a periodic orbit within a very narrow interval of a control parameter, is the result of multiple time scales in a dynamical system and is common in excitable systems. Coherent biresonance, namely, two peaks on the signal-to-noise ratio (SNR) curve when varying noise intensity, is a novel phenomenon of coherent resonance which is well-known in excitable systems. When the control parameter is varied from a stable fixed point, crossing the supercritical Hopf bifurcation, one of the peaks that corresponds to relatively larger noise intensity, keeps a constant height and position, while the other becomes higher and moves to lower noise level. When we consider the case in which two control parameters are perturbed by independent noise simultaneously, an interesting picture of one valley between two ridges appears on the 3D surface of SNR.

Carbon Monoxide↗
PubMed2005

Frequency-selective response of periodically forced coupled FHN models via system size multi-resonance.

We consider system of globally coupled FitzHugh-Nagumo (FHN) models; each element is subjected to a subthreshold periodic signal and independent Gaussian white noise. With the variation of the system size, the spike train of the mean field of the system fires according to the period of the subthreshold external signal or to the interior time scale of the FHN model. The influence of the coupling strength is also investigated. It only influences the response of the mean field to external signal. If two external signals are injected to the system simultaneously, the least-common-multiple periods or other common multiples may be selected by different system sizes.

Computer Simulation↗
PubMed2005

Internal noise stochastic resonance for intracellular calcium oscillations in a cell system.

By constructing a mesoscopic stochastic model for intracellular calcium oscillations in a cell system, we have investigated how the internal noise would influence the calcium oscillations of such a system using stochastic simulation methods and chemical Langevin method. It is found that stochastic calcium oscillations appear when the internal noise is considered, while the deterministic model only yields steady state. The performance of such oscillations undergoes a maximum with the variation of the internal noise level, indicating the occurrence of internal noise stochastic resonance. Interestingly, we find that the optimal system size matches well with the real cell size when the control parameter is tuned near the left Hopf bifurcation point, and such a match is robust to the variation of the control parameters.

Biological Clocks↗
PubMed2005

Effects of internal noise for rate oscillations during CO oxidation on platinum surfaces.

We have studied the influence of internal noise on the reaction rate oscillation during carbon-monoxide oxidation on single crystal platinum surfaces using chemical Langevin equations. Considering that the surface is divided into small well-mixed cells, we have focused on the dynamic behavior inside a single cell. Internal noise can induce rate oscillations and the performance of the stochastic rate oscillations shows double maxima with the variation of the internal noise intensity, demonstrating the occurrence of internal noise coherent biresonance. The relationship between such a phenomenon with the deterministic bifurcation features of the system is also discussed.

Journal Article↗
PubMed2005

Internal noise stochastic resonance in NO reduction by CO on platinum surfaces.

We have studied the roles of internal noise in the oscillatory reaction kinetics during NO reduction by CO on low-index single crystal platinum surfaces using the chemical Langevin equation and the Poisson approximation algorithm. Considering that the surface is divided into small well-mixed cells, we have focused on the dynamical behavior inside a single cell. It is found that internal noise can induce rate oscillations and the performance of the stochastic rate oscillations undergoes a maximum with the variation of internal noise level for a given NO partial pressure, demonstrating the occurrence of internal noise stochastic resonance. Such a phenomenon is robust to the change of external parameters, such as NO pressures. Interestingly, it is also found that internal noise noticeably alters the oscillatory waveform and, hence, the reaction activity and oscillation signal intensity, but it nearly does not change the global reaction rate.

Journal Article↗
PubMed2003

Oscillator death on small-world networks.

We have investigated the oscillator death behavior on small-world networks. On one hand, we find that small-world connectivity can eliminate the oscillator death present in the regular lattice. On the other hand, the small-world connectivity can also lead to global oscillator death which is absent in the regular lattice or the completely random network.

Journal Article↗
PubMed2003

Ordering chaos by random shortcuts.

In this Letter, the effects of random shortcuts in an array of coupled nonlinear chaotic pendulums and their ability to control the dynamical behavior of the system are investigated. We show that random shortcuts can induce periodic synchronized spatiotemporal motions, even though all oscillators are chaotic when uncoupled. This process exhibits a nonmonotonic dependence on the density of shortcuts. Specifically, there is an optimal amount of random shortcuts, which can induce the most ordered motion characterized by the largest order parameter that is introduced to measure the spatiotemporal order. Our results imply that topological randomness can tame spatiotemporal chaos.

Journal Article↗