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Abstract: In this paper, we consider a HIV infection model with CTL-response delay and analyze the effect of time delay on stability of equilibria. We obtain the global stability of the infection-free equilibrium and give sufficient conditions for the local stability of the CTL-absent equilibrium and CTL-present equilibrium. By choosing the CTL-response delay as a bifurcation parameter, we prove that the CTL-present equilibrium is locally asymptotically stable in a range of delays and a Hopf bifurcation occurs as crosses a critical value. Numerical simulations are given to support the theoretical results. [Copyright &y& Elsevier]

Abstract: In this paper, we consider a tri-neuron network model with discrete and distributed delays. After discussing the distributions of the roots of the characteristic equation local stability analysis of the steady-state solution leads to, we analyze the stability of network models with instantaneous feedback and neural interaction history, delayed neural feedback and no neural interaction history and delayed neural feedback and neural interaction history; we give sufficient conditions for the linear stability of the equilibrium solution; we also show that a Hopf bifurcation can occur when the delays take certain critical values; and we further prove that there is a positive integer K such that there are K switches from stability to instability and back to stability. Numerical simulations are finally performed to illustrate the obtained results. [Copyright &y& Elsevier]

Abstract: We derive a class of delay difference equations with piecewise constant nonlinearity. The convergence of solutions and the existence of asymptotically stable periodic solutions are investigated, for such a class of difference equations. [Copyright &y& Elsevier]

This paper is concerned with a delay differential system with piecewise constant nonlinearity. Such a differential system can be regarded as a model of two-neuron artificial neural network with delayed feedback. Some interesting results are obtained for the convergence and periodicity of solutions of the system. [Copyright &y& Elsevier]

Abstract: In this paper, we consider a class of delay difference systems with piecewise constant nonlinearity, which includes the discrete version of an artificial neural network model of two neurons described by differential equations with piecewise constant arguments. Some interesting results are obtained for the periodicity and convergence of solutions of the systems. [Copyright &y& Elsevier]

Abstract: The effect of amount of flour in the pre-fermented form (10%, 20%, and 30% flour in the pre-fermented form), fermentation time (12, 24, and 36h), and amount of yeast (0.5%, 1.0%, and 1.5%) on acidity, specific volume, and crumb texture of Chinese Northern-style sourdough steamed breads were studied. Volatile compounds of the sourdough and non-sourdough steamed breads were also determined. The preferments were produced from spontaneous fermentation using all purpose (APF) and whole wheat flours (WWF). Specific volume was the highest at 20% preferment for APF sourdough steamed bread (ASSB) and 30% preferment for WWF sourdough steamed bread (WSSB). The softest texture was obtained with 20% preferment while at 30% preferment there was excessive gluten weakening due to high acidification. A total of 89 volatile compounds were identified in steamed breads with ethanol and 3-methyl-1-butanol being the most abundant compounds. [Copyright &y& Elsevier]

This paper gives new conditions ensuring global asymptotic stability and global exponential stability for cellular neural networks with constant delay and variable delay, respectively. These conditions are derived by using the essence of piecewise linearity of the output function of cellular neural networks and by constructing Lyapunov functions and functionals. Furthermore, these conditions are significantly weaker than those given in existing literature. [Copyright &y& Elsevier]