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Thomas Wilhelm - One of the best experts on this subject based on the ideXlab platform.

  • the smallest chemical reaction system with Bistability
    BMC Systems Biology, 2009
    Co-Authors: Thomas Wilhelm
    Abstract:

    Background Bistability underlies basic biological phenomena, such as cell division, differentiation, cancer onset, and apoptosis. So far biologists identified two necessary conditions for Bistability: positive feedback and ultrasensitivity.

  • The smallest chemical reaction system with Bistability
    BMC Systems Biology, 2009
    Co-Authors: Thomas Wilhelm
    Abstract:

    BACKGROUND: Bistability underlies basic biological phenomena, such as cell division, differentiation, cancer onset, and apoptosis. So far biologists identified two necessary conditions for Bistability: positive feedback and ultrasensitivity.\n\nRESULTS: Biological systems are based upon elementary mono- and bimolecular chemical reactions. In order to definitely clarify all necessary conditions for Bistability we here present the corresponding minimal system. According to our definition, it contains the minimal number of (i) reactants, (ii) reactions, and (iii) terms in the corresponding ordinary differential equations (decreasing importance from i-iii). The minimal bistable system contains two reactants and four irreversible reactions (three bimolecular, one monomolecular).We discuss the roles of the reactions with respect to the necessary conditions for Bistability: two reactions comprise the positive feedback loop, a third reaction filters out small stimuli thus enabling a stable 'off' state, and the fourth reaction prevents explosions. We argue that prevention of explosion is a third general necessary condition for Bistability, which is so far lacking discussion in the literature.Moreover, in addition to proving that in two-component systems three steady states are necessary for Bistability (five for tristability, etc.), we also present a simple general method to design such systems: one just needs one production and three different degradation mechanisms (one production, five degradations for tristability, etc.). This helps modelling multistable systems and it is important for corresponding synthetic biology projects.\n\nCONCLUSION: The presented minimal bistable system finally clarifies the often discussed question for the necessary conditions for Bistability. The three necessary conditions are: positive feedback, a mechanism to filter out small stimuli and a mechanism to prevent explosions. This is important for modelling Bistability with simple systems and for synthetically designing new bistable systems. Our simple model system is also well suited for corresponding teaching purposes.

Marko Loncar - One of the best experts on this subject based on the ideXlab platform.

Raji Shankar - One of the best experts on this subject based on the ideXlab platform.

Lisa M Bishop - One of the best experts on this subject based on the ideXlab platform.

  • the chemical master equation approach to nonequilibrium steady state of open biochemical systems linear single molecule enzyme kinetics and nonlinear biochemical reaction networks
    International Journal of Molecular Sciences, 2010
    Co-Authors: Hong Qian, Lisa M Bishop
    Abstract:

    We develop the stochastic, chemical master equation as a unifying approach to the dynamics of biochemical reaction systems in a mesoscopic volume under a living environment. A living environment provides a continuous chemical energy input that sustains the reaction system in a nonequilibrium steady state with concentration fluctuations. We discuss the linear, unimolecular single-molecule enzyme kinetics, phosphorylation-dephosphorylation cycle (PdPC) with Bistability, and network exhibiting oscillations. Emphasis is paid to the comparison between the stochastic dynamics and the prediction based on the traditional approach based on the Law of Mass Action. We introduce the difference between nonlinear Bistability and stochastic Bistability, the latter has no deterministic counterpart. For systems with nonlinear Bistability, there are three different time scales: (a) individual biochemical reactions, (b) nonlinear network dynamics approaching to attractors, and (c) cellular evolution. For mesoscopic systems with size of a living cell, dynamics in (a) and (c) are stochastic while that with (b) is dominantly deterministic. Both (b) and (c) are emergent properties of a dynamic biochemical network; We suggest that the (c) is most relevant to major cellular biochemical processes such as epi-genetic regulation, apoptosis, and cancer immunoediting. The cellular evolution proceeds with transitions among the attractors of (b) in a “punctuated equilibrium” manner.

SUDIP KUMAR BATABYAL - One of the best experts on this subject based on the ideXlab platform.

  • Electrical Bistability and memory switching phenomenon in Cu_2FeSnS_4 thin films: role of p-n junction
    Journal of Solid State Electrochemistry, 2019
    Co-Authors: Sreejith P. Madhusudanan, Kallol Mohanta, SUDIP KUMAR BATABYAL
    Abstract:

    Electrical Bistability of Cu_2FeSnS_4 (CFTS) thin films fabricated via successive ionic layer adsorption and reaction (SILAR) method was studied here. The SILAR method is a simple and cost-effective method for large area thin film production. Though CFTS thin films have been fabricated for the last few years, neither the electrical memory applications nor the electrical Bistability of these films has been studied yet. In this report, we have shown that the electrical characteristics of the CFTS films could be useful for the random-access memory (RAM) applications. A detailed investigation to understand the electrical Bistability has been carried out. We found that conducting channels were formed inside the films when a suitable bias voltage is applied and that could be reset with an opposite bias voltage to establish electrical Bistability. The p-n junction configuration restricted the percolation and formation of conducting filament. Thus, no electrical Bistability were observed for the CFTS p-n junction.