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Vanag VK. Plasticity in networks of active chemical cells with pulse coupling. CHAOS (WOODBURY, N.Y.) 2022; 32:123108. [PMID: 36587337 DOI: 10.1063/5.0110190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/09/2022] [Indexed: 06/17/2023]
Abstract
A method for controlling the coupling strength is proposed for pulsed coupled active chemical micro-cells. The method is consistent with Hebb's rules. The effect of various system parameters on this "spike-timing-dependent plasticity" is studied. In addition to networks of two and three coupled active cells, the effect of this "plasticity" on the dynamic modes of a network of four pulse-coupled chemical micro-cells unidirectionally coupled in a circle is studied. It is shown that the proposed adjustment of the coupling strengths leads to spontaneous switching between network eigenmodes.
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Affiliation(s)
- Vladimir K Vanag
- Centre for Nonlinear Chemistry, Immanuel Kant Baltic Federal University, 14 A. Nevskogo St., Kaliningrad 236041, Russia
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Bose A, Gorecki J. Computing With Networks of Chemical Oscillators and its Application for Schizophrenia Diagnosis. Front Chem 2022; 10:848685. [PMID: 35372264 PMCID: PMC8966613 DOI: 10.3389/fchem.2022.848685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/03/2022] [Indexed: 11/25/2022] Open
Abstract
Chemical reactions are responsible for information processing in living organisms, yet biomimetic computers are still at the early stage of development. The bottom-up design strategy commonly used to construct semiconductor information processing devices is not efficient for chemical computers because the lifetime of chemical logic gates is usually limited to hours. It has been demonstrated that chemical media can efficiently perform a specific function like labyrinth search or image processing if the medium operates in parallel. However, the number of parallel algorithms for chemical computers is very limited. Here we discuss top-down design of such algorithms for a network of chemical oscillators that are coupled by the exchange of reaction activators. The output information is extracted from the number of excitations observed on a selected oscillator. In our model of a computing network, we assume that there is an external factor that can suppress oscillations. This factor can be applied to control the nodes and introduce input information for processing by a network. We consider the relationship between the number of oscillation nodes and the network accuracy. Our analysis is based on computer simulations for a network of oscillators described by the Oregonator model of a chemical oscillator. As the example problem that can be solved with an oscillator network, we consider schizophrenia diagnosis on the basis of EEG signals recorded using electrodes located at the patient’s scalp. We demonstrated that a network formed of interacting chemical oscillators can process recorded signals and help to diagnose a patient. The parameters of considered networks were optimized using an evolutionary algorithm to achieve the best results on a small training dataset of EEG signals recorded from 45 ill and 39 healthy patients. For the optimized networks, we obtained over 82% accuracy of schizophrenia detection on the training dataset. The diagnostic accuracy can be increased to almost 87% if the majority rule is applied to answers of three networks with different number of nodes.
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Hunter I, Norton MM, Chen B, Simonetti C, Moustaka ME, Touboul J, Fraden S. Pattern formation in a four-ring reaction-diffusion network with heterogeneity. Phys Rev E 2022; 105:024310. [PMID: 35291089 DOI: 10.1103/physreve.105.024310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 01/28/2022] [Indexed: 11/07/2022]
Abstract
In networks of nonlinear oscillators, symmetries place hard constraints on the system that can be exploited to predict universal dynamical features and steady states, providing a rare generic organizing principle for far-from-equilibrium systems. However, the robustness of this class of theories to symmetry-disrupting imperfections is untested in free-running (i.e., non-computer-controlled) systems. Here, we develop a model experimental reaction-diffusion network of chemical oscillators to test applications of the theory of dynamical systems with symmeries in the context of self-organizing systems relevant to biology and soft robotics. The network is a ring of four microreactors containing the oscillatory Belousov-Zhabotinsky reaction coupled to nearest neighbors via diffusion. Assuming homogeneity across the oscillators, theory predicts four categories of stable spatiotemporal phase-locked periodic states and four categories of invariant manifolds that guide and structure transitions between phase-locked states. In our experiments, we observed that three of the four phase-locked states were displaced from their idealized positions and, in the ensemble of measurements, appeared as clusters of different shapes and sizes, and that one of the predicted states was absent. We also observed the predicted symmetry-derived synchronous clustered transients that occur when the dynamical trajectories coincide with invariant manifolds. Quantitative agreement between experiment and numerical simulations is found by accounting for the small amount of experimentally determined heterogeneity in intrinsic frequency. We further elucidate how different patterns of heterogeneity impact each attractor differently through a bifurcation analysis. We show that examining bifurcations along invariant manifolds provides a general framework for developing intuition about how chemical-specific dynamics interact with topology in the presence of heterogeneity that can be applied to other oscillators in other topologies.
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Affiliation(s)
- Ian Hunter
- Brandeis University Physics, Waltham, Massachusetts 02453, USA
| | - Michael M Norton
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Bolun Chen
- Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02453, USA.,Department of Physics, Boston University, Boston Massachusetts 02215, USA
| | - Chris Simonetti
- Brandeis University Physics, Waltham, Massachusetts 02453, USA
| | | | - Jonathan Touboul
- Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02453, USA.,Brandeis University Mathematics Department, Waltham, Massachusetts 02453, USA
| | - Seth Fraden
- Brandeis University Physics, Waltham, Massachusetts 02453, USA
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Zhang Z, Xu L, Huang J. Controlling Chemical Waves by Transforming Transient Mass Transfer. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202100375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Zeren Zhang
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Shanghai 200438 China
| | - Liujun Xu
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Shanghai 200438 China
| | - Jiping Huang
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Shanghai 200438 China
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Mallphanov IL, Vanag VK. Chemical micro-oscillators based on the Belousov–Zhabotinsky reaction. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr5009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
The results of studies on the development of micro-oscillators (MOs) based on the Belousov –Zhabotinsky (BZ) oscillatory chemical reaction are integrated and systematized. The mechanisms of the BZ reaction and the methods of immobilization of the catalyst of the BZ reaction in micro-volumes are briefly discussed. Methods for creating BZ MOs based on water microdroplets in the oil phase and organic and inorganic polymer microspheres are considered. Methods of control and management of the dynamics of BZ MO networks are described, including methods of MO synchronization. The prospects for the design of neural networks of MOs with intelligent-like behaviour are outlined. Such networks present a new area of nonlinear chemistry, including, in particular, the creation of a chemical ‘computer’.
The bibliography includes 250 references.
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Safonov DA, Vanag VK. Oscillatory microcells connected on a ring by chemical waves. CHAOS (WOODBURY, N.Y.) 2021; 31:063134. [PMID: 34241281 DOI: 10.1063/5.0046051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
The dynamics of four coupled microcells with the oscillatory Belousov-Zhabotinsky (BZ) reaction in them is analyzed with the aid of partial differential equations. Identical BZ microcells are coupled in a circle via identical narrow channels containing all the components of the BZ reaction, which is in the stationary excitable state in the channels. Spikes in the BZ microcells generate unidirectional chemical waves in the channels. A thin filter is put in between the end of the channel and the cell. To make coupling between neighboring cells of the inhibitory type, hydrophobic filters are used, which let only Br2 molecules, the inhibitor of the BZ reaction, go through the filter. To simulate excitatory coupling, we use a hypothetical filter that let only HBrO2 molecules, the activator of the BZ reaction, go through it. New dynamic modes found in the described system are compared with the "old" dynamic modes found earlier in the analogous system of the "single point" BZ oscillators coupled in a circle by pulses with time delay. The "new" and "old" dynamic modes found for inhibitory coupling match well, the only difference being much broader regions of multi-rhythmicity in the "new" dynamic modes. For the excitatory type of coupling, in addition to four symmetrical modes of the "old" type, many new asymmetrical modes coexisting with the symmetrical ones have been found. Asymmetrical modes are characterized by the spikes occurring any time within some finite time intervals.
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Affiliation(s)
- Dmitry A Safonov
- Centre for Nonlinear Chemistry, Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., Kaliningrad 236041, Russia
| | - Vladimir K Vanag
- Centre for Nonlinear Chemistry, Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., Kaliningrad 236041, Russia
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Proskurkin IS, Smelov PS, Vanag VK. Experimental verification of an opto-chemical "neurocomputer". Phys Chem Chem Phys 2020; 22:19359-19367. [PMID: 32822448 DOI: 10.1039/d0cp01858a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A theoretically predicted hierarchical network of pulse coupled chemical micro-oscillators and excitable micro-cells that we call a chemical "neurocomputer" (CN) or even a chemical "brain" is tested experimentally using the Belousov-Zhabotinsky reaction. The CN consists of five functional units: (1) a central pattern generator (CPG), (2) an antenna, (3) a reader for the CPG, (4) a reader for the antenna unit, and (5) a decision making (DM) unit. A hybrid CN, in which such chemical units as readers and DM units are replaced by electronic units, is tested as well. All these variations of the CN respond intelligently to external signals, since they perform an automatic transition from a current to a new dynamic mode of the CPG, which is similar to the antenna dynamic mode that in turn is induced by external signals. In other words, we show for the first time that a network of pulse coupled chemical micro-oscillators is capable of intelligent adaptive behavior.
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Affiliation(s)
- Ivan S Proskurkin
- Centre for Nonlinear Chemistry, Immanuel Kant Baltic Federal University, Kaliningrad, 236041, Russia.
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