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An alternative approach using visible chemical waves for ethanol determination is presented. The method is based on the dynamic change of chemical waves in the Belousov-Zhabotinsky (BZ) reaction by perturbation with ethanol. The observablepropagating waves, generatedina Petri dish, can be recorded by using a smartphone camera. The propagating distances are measured from photographic images and then plotted as a function of time to attain the wave velocity. It is found that wave velocities are inversely proportional to ethanol concentrations. By using this linear relationship, the ethanol content can be efficiently quantified with good intra-day and inter-day precision (<3% RSD). Validated by the GC technique, the developed method is highly reliable and successfully applied for quantifying the ethanol content in beer, colored whisky, and vodka samples. Hence, this new method provides an alternative practical strategy for simple quantitative detection of ethanol without the need for instruments. [ABSTRACT FROM AUTHOR]

Abstract: We report our experimental observation of modulated standing waves that invade bulk oscillations exhibited by the Belousov‐Zhabotinsky‐Aerosol OT reverse microemulsion system. The modulated standing waves form within domains bounded by a traveling wave. We also observe that the modulated standing waves give way to traveling waves, which we connect to numerical simulations in a simple chemical model. [ABSTRACT FROM AUTHOR]

Temporal oscillations of the cerium(IV)-catalysed Belousov-Zhabotinsky reaction under addition of various Br- concentrations are investigated. The relationship between the induction period and Br- concentration, which is a controlling species in the BZ oscillating reaction, is reported. The oscillations of the Ce(IV) catalyst are followed by using UV-Vis spectrophotometric methods under closed batch and oxygen free systems. Experimental observations demonstrate that increasing Br- concentration decreases the induction period exponentially, whereas it increases the oscillation period linearly. The results reveal that the oscillations without induction period are observed by the addition of 1.0 × 10-2 M Br- concentration. Addition of Br- into the BZ solution mainly involves the process A of the FKN mechanism. Numerical results reveal that the addition of Br- increases the production of BrMA, but decreases the induction period. [ABSTRACT FROM AUTHOR]

Spiral waves are observed in wide variety of reaction-diffusion systems. Those observed in cardiac tissues are important since they are related to serious disease that threatens human lives, such as atrial or ventricular fibrillation. We consider the unpinning of spiral waves anchored to a circular obstacle on excitable media using high-frequency pacing. Here, we consider two types of the obstacle; i.e., that without any diffusive interaction with the environment, and that with diffusive interaction. We found that the threshold frequency for success in unpinning is lower for the obstacle with diffusive interaction than for the one without it. We discuss the threshold frequency based on the angular velocity of a chemical wave anchoring the obstacle. [ABSTRACT FROM AUTHOR]

An enhanced version of the Wireworld cellular automaton called Wireworld++ is introduced. It can be considered as a generalization of Wireworld suitable for modeling digital electronic circuits that have intersections of unconnected wires. As most electronic circuits except trivial ones have wire crossings, Wireworld++ is a more convenient cellular automaton for modeling digital electronics than the conventional Wireworld. Wireworld++ is two dimensional; it has a small number of states and simple and intuitive rules. Despite that, it allows simulation of three-dimensional elements of digital circuits, for instance, wire crossings or electronic components placed on both sides of printed circuit boards. The key electronic parts, such as logic gates, implemented in Wireworld++ exhibit more symmetry and utilize fewer cells than their Wireworld counterparts. Wireworld++ can also be applied to simulation of computing devices in a sub-excitable, light-sensitive Belousov-Zhabotinsky medium organized in a rectangular grid of vesicles. [ABSTRACT FROM AUTHOR]

A novel gel undergoes the Belousov-Zhabotinsky (BZ) reaction in strong-acid-free conditions. Under such conditions, the gel can switch the BZ reaction on or off in conventional self-oscillating gels that undergo self-oscillation only in aqueous solutions with strong acids, such as HNO3 or H2SO4. The self-oscillation of the polymer chain can be controlled by varying the temperature, owing to its thermoresponsive property. Moreover, the polymer chain undergoes viscosity self-oscillations in strong-acid-free conditions. In this review, the direct observation of self-oscillations in polymer chains attached to glass or gold surfaces, by using scanning probe microscopy and quartz crystal microbalances with dissipation monitoring, is discussed.

Oscillatory chemical reactions have been drawing the attention of researchers for a number of decades. More recently, the ability of the reactions to work as the driving force for smart materials became attractive in the quest for biomedical applications, such as pulsatile drug delivery and controlled tissue proliferation. Owing to recent developments in the field, these fascinating reactions have advanced from taking place in solution to polymer based soft materials. In this review we discuss the current state of the art and steps on the way to fully autonomous all-polymeric rhythmic materials and share our personal perspective about the future of oscillatory chemical reactions. [ABSTRACT FROM AUTHOR]

Waves of chemical concentration, created by the interaction between reaction and diffusion, occur in a number of chemical systems far from equilibrium. In appropriately chosen polymer gels, these waves generate mechanical forces, which can result in locomotion. When a component of the system is photosensitive, light can be used to modulate and control these waves. In this Concept article, we examine various forms of photo-control of such systems, focusing particularly on the Belousov-Zhabotinsky oscillating chemical reaction. The phenomena we consider include image storage and image processing, feedback-control and feedback-induced clustering of waves, and phototropic and photophobic locomotion. Several of these phenomena have analogues in or potential applications to biological systems. [ABSTRACT FROM AUTHOR]

Periodic to-and-fro migration is a sophisticated mode of locomotion found in many forms of active matter in nature. Providing a general description of periodic migration is challenging, because many details of animal migration remain a mystery. We study periodic migration in a simpler system using a mechanistic model of a photosensitive, active material in which a stimulus-responsive polymer gel is propelled by chemical waves under the regulation of an illumination gradient sensed by the gel, which plays a role analogous to the environment in periodic animal migration. The reciprocating gel migration results from autonomous transitions between retrograde and direct wave locomotion modes arising from the gradient distribution of the illumination intensity. The local dynamics of the chemical waves modulates the asymmetry between push and pull forces to achieve repeated reorientation of the direction of locomotion. Materials that display similar intelligent, self-adaptive locomotion might be tailored for such functions as drug delivery or self-cleaning systems. [ABSTRACT FROM AUTHOR]

Spiral waves are often observed in wide variety of reaction-diffusion systems. Those in cardiac tissues are important since they are related to serious disease that threatens human lives, such as atrial and ventricular fibrillation. We consider the unpinning of spiral waves around two types of defects using high-frequency pacing. The defects are classified into two kinds, i.e, that without any diffusive interaction with the environment, and that with diffusive interaction. We found that the threshold frequency is lower for the defect with diffusive interaction than for the one without it. [ABSTRACT FROM AUTHOR]

The continuous increment in the performance of classical computers has been driven to its limit. New ways are studied to avoid this oncoming bottleneck and many answers can be found. An example is the Belousov-Zhabotinsky (BZ) reaction which includes some fundamental and essential characteristics that attract chemists, biologists, and computer scientists. Interaction of excitation wave-fronts in BZ system, can be interpreted in terms of logical gates and applied in the design of unconventional hardware components. Logic gates and other more complicated components have been already proposed using different topologies and particular characteristics. In this study, the inherent parallelism and simplicity of Cellular Automata (CAs) modeling is combined with an Oregonator model of light-sensitive version of BZ reaction. The resulting parallel and computationally-inexpensive model has the ability to simulate a topology that can be considered as a one-bit full adder digital component towards the design of an Arithmetic Logic Unit (ALU). [ABSTRACT FROM AUTHOR]

Dynamical synchronous modes in a network of four nearly identical chemical oscillators unidirectionally coupled via inhibitory pulse coupling with time delay τ (when a spike in one oscillator inhibits the next oscillator in the circle after time delay τ), are obtained experimentally. The Belousov-Zhabotinsky reaction is used as a chemical oscillator. The existence of four main modes is confirmed experimentally: in-phase (IP) oscillations; an anti-phase (AP) mode, in which any two neighboring oscillators have a phase shift equal to half of global period T; a walk mode (W), in which oscillators produce consecutive spikes in the direction of the connection with a phase shift between neighboring oscillators equal to T/4; and a walk-reverse mode (WR), when the oscillators produce consecutive spikes (with phase shift T/4), but in the direction opposite the connections (the mode opposite to the W mode). In addition to the main modes, OS modes in which at least one of the four oscillators is suppressed, and '2+1+1' modes in which two neighboring oscillators produce spikes simultaneously and the phases of the third and the fourth oscillators are shifted by T/3 and 2 T/3, respectively, are found. It is shown that the modes found experimentally correspond to those found in simulations. [ABSTRACT FROM AUTHOR]

This paper describes the nonlinear behaviour of the acetaminophen-based uncatalysed Belousov-Zhabotinsky oscillator and its dynamics in the presence of ferroin as catalyst. The role of free metal ions as catalysts was examined and the results compared with those of corresponding complexed catalysts. Free metal ions were found to be sluggish with respect to the evolution of the oscillatory regime as compared to complexed ones. The effect was monitored of change of the ligand moiety of the catalyst complex on the oscillatory parameters. Since ethanol potentiates the hepatotoxicity caused by acetaminophen in vivo, it is thought to understand this interaction by virtue of causing perturbation of the acetaminophen-based oscillator with different concentrations of ethanol with and without ferroin as catalyst. Another dimension to the ethanol effect was examined by perturbation of the system with ethanol at different stages of the reaction so as to get an idea as to whether it is acetaminophen or some reactive intermediate generated in the reaction system which reacts with ethanol. Further, the ferroin-catalysed oscillator is taken as a prototype inorganic model of the acetaminophen- ethanol syndrome, as ferroin and hypobromous acid (HOBr) act as inorganic replacements for cytochrome P450 and nicotinamide adenine dinucleotide phosphate (NADPH) in alcohol metabolism. [ABSTRACT FROM AUTHOR]

Ruthenium-functionalized poly( N-isopropyl acrylamide)-based chemically oscillating microgels with diameters between 1 and 6 µm are synthesized by a modified precipitation polymerization approach. It is found that the initial amount of N-isopropyl acrylamide (NIPAAm) can significantly affect the final sizes of the microgels. 2.5 g of initial NIPAAm results in microgels with maximum average diameter of ≈6 ± 0.5 µm. Making use of their fluorescence due to their ruthenium contents and their larger sizes compared to microgels prepared using other traditional methods, the impact of changes in the NaBrO3 concentrations on their microscopic behavior is studied using a combination of fluorescence microscopy and dynamic light scattering techniques. When increasing the concentration of NaBrO3 in a solution, the microgels first experience a decrease in size followed by aggregation that leads to the loss of colloidal stability. Finally, the redox potential behavior and optical performance of the Belousov-Zhabotinsky reaction catalyzed by these microgels are studied by electrochemical and spectroscopic means. [ABSTRACT FROM AUTHOR]

Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ) medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, , , and Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies. [ABSTRACT FROM AUTHOR]

• Quartz botryoids in Apex and Strelley Pool cherts simulate those developed by the COR. • These Palaeoarchean structures originated from decarboxylation of carboxylic acids. • An abiotic model for early diagenetic growth of the studied quartz botryoids is proposed. Chemically oscillating reactions (COR) are abiotic processes that generate self-repeating circularly concentric morphologies during decarboxylation of organic acids. The geometry and millimetre to centimetre size dimensions of laminated quartz botryoids recorded in the Palaeoarchean Apex and Strelley Pool chert horizons in Western Australia simulate the self-similar fractal patterns arising in vitro from COR using classical and modified reactants of the Belousov-Zhabotinsky (B-Z) reaction. The botryoidal patterns akin to those developed by the COR include circular concentric laminae, open-book features, microbialite- and stromatolite-like laminations, wavy and domal structures, and rosettes. The mineral composition and organic matter (OM) distribution of these objects indicates an origin from the early diagenetic decarboxylation of carboxylic acids. Pore-water alkalinity decrease is likely due to the decomposition of OM, the generation of carbonic acid, and the cessation of chemical wave diffusion. The chemical waves developed from primary circular oxidation spots, under solubility equilibrium with respect to silica could trigger diagenetic precipitation of quartz. The presence of Fe2+-bearing hematite in various botryoidal geometries in the Apex chert is an analogue of ferroin-derived Fe in B-Z solutions, whereas the presence of Fe and Zn sulphides in the Strelley Pool quartz botryoids is akin to sulphur redox intermediates in B-Z experiments. Correlated microscopy and Raman spectral analysis corroborate that the metamorphosed OM associated with these Palaeoarchean botryoids is indigenous and syngenetic with the host chert. OM in botryoidal quartz displays circular concentric laminations as well as gradients of its density. Accordingly, an abiotic model of COR for the diagenetic growth of the studied Apex and Strelley Pool quartz botryoids is proposed. Comparisons with the chemical compositions, geometric morphology and range of size dimensions of self-similar patterns have been the criteria for development of this model expression. The explored ancient botryoids can thus represent abiotic sedimentological signatures of carbon cycling. [ABSTRACT FROM AUTHOR]

In this work we present results about the deuterium isotope effect on the globalkinetics of a Belousov-Zhabotinsky reaction in batch conditions. A nonlinear dependenceof the Induction Period upon the percentage of deuterated reactants was found. The isotopiceffect on the bromination reaction of malonic acid was evaluated.

Crawling motion mediated by retrograde and direct waves, that is, in the opposite or the same direction, respectively, as the muscular wave that generates it, is a fundamental mode of biological locomotion, from which more complex and sophisticated locomotion modes involving outgrowths such as limbs and wings may have evolved. A detailed general description of muscular wave locomotion and its relationship with other modes of locomotion is a challenging task. We employ a model of a photosensitive self-oscillating gel, in which chemical pulse waves and a stimulus-responsive medium play roles analogous to nerve pulses and deformable muscles in an animal, to generate retrograde and direct waves under non-uniform illumination. Analysis reveals that the directional locomotion arises from a force asymmetry that results in unequal translation lengths in the push and pull regions associated with a pulse wave. This asymmetry can be modulated by the kinetic parameters of the photosensitive Belousov-Zhabotinsky reaction and the performance parameters of the gel, enabling a transition between retrograde and direct wave locomotion. [ABSTRACT FROM AUTHOR]

The fractional-order Belousov-Zhabotinsky (BZ) reaction with different time scales is investigated in this paper. Based on the stability theory of fractional-order differential equation, the critical condition of Hopf bifurcation with two parameters in fractional-order BZ reaction is discussed. By comparison of the fractional-order and integer-order systems, it is found that they will behave in different stabilities under some parameter intervals, and the parameter intervals may become larger with the variation of fractional order. Furthermore, slow-fast effect is firstly studied in fractional-order BZ reaction with two time scales coupled, and the Fold/Fold type slow-fast oscillation with jumping behavior is found, whose generation mechanism is explained by using the slow-fast dynamical analysis method. The influences of different fractional orders on the slow-fast oscillation behavior as well as the internal mechanism are both analyzed. [ABSTRACT FROM AUTHOR]

Core/shell double emulsions were fabricated using glasscapillary based microfluidic techniques. Poly(butadiene) 46-bpoly(ethylene oxide)30 in mixture with cyclo-hexane/chloroform were contained as the shell part of droplets, whose core part was the full 1,4-cyclohexadiene based Belousov-Zhabotinsky reaction solution of unknown osmolality. The droplets were collected in solutions of both low and relatively high concentrations of salt. This resulted in the respective increase or decrease of the core part diameter. In both cases, after an incubation period, the droplets eventually evolved into polymer vesicles. In solutions with low concentration of salt, the droplets evolved into polymer vesicles after the evaporation of the vola-tile solvent contained in the shell part. Due to the dewetting of the shell and core parts，droplets in solutions of relatively high salt concentration evolved into polymer vesicles only after three days of incubation. The dewetted shell part displayed crescent-moon-shapes with different curvatures. The final diameter of the vesicles differed from the diameter of the initial core droplets. We demonstrate that vesicles with unknown osmolality core parts are formed in both solutions of very low or relatively high concentration of salt; furthermore, we also demonstrate that they follow different formation pathways. In the appropriate conditions, the vesicles experienced a form of “collapsing” behavior due to the activity of the entrapped chemical reaction. [ABSTRACT FROM AUTHOR]

Some new experimental evidence of complex irregular oscillations in the Belousov–Zhabotinsky reaction realized in a batch reactor is presented. The results were obtained under relatively low cerium and malonic acid concentrations. One-dimensionalmaps were used for general discussion, and, particularly, for the influence of noise on the evolution of the oscillations.