The collective behavior of an ensemble of multimode stochastic oscillators is investigated. The oscillators are pulse coupled; they are able to emit pulses and to detect the pulses emitted by the others. As a function of the output intensity in the system they can operate in different modes having different pulsing periods. The system is designed to optimize the output intensity around a fixed f* output threshold. In order to do so a simple dynamics is considered. Whenever the total output intensity in the system is lower than f*, a mode with a higher interpulse period is chosen. If the light intensity in the system is higher than f*, a mode with a lower interpulse period is selected. As a side effect of this simple optimization rule, for a given f* interval a nontrivial synchronization of the oscillators is observed. The synchronization level is studied by computer simulations, investigating the influence of model parameters (number of modes, stochasticity of the oscillators, the f* threshold value, and interaction topology). An experimental realization of this system is also considered; an ensemble of electronic oscillators communicating with light pulses was constructed and studied. The experimental system behaves in many ways similar to the theoretically considered multimode stochastic oscillator ensemble.
Due to the continuously increasing trend in the costs of the traditional fossil fuels, the development of residential or commercial buildings with reduced energy needs becomes a significant and more pressing scientific challenge. At the same time, consumers are increasingly demanding more comfortable buildings, where the energy needs are addressed using locally available renewable energy resources. Consumers also require a higher level of security, supervision, and control of the building, depending on the needs of the users. The abovementioned expectations present building automation systems design engineers with a challenging situation, which is difficult to approach using classical methods or strategies. As a result, this paper outlines novel facilities and solutions offered by the current level microelectronics in building mechatronics systems development and implementation. In the first step of this endeavor, the benefits of the reconfigurable technology are highlighted and explained. Next, available hardware resources are presented, especially examining the novel FPGA processors-based architectures suited for building automation applications. The feasibility and versatility of such a reconfigurable hardware configuration and parallel computing digital system were tested in a concrete building supervising and control application. The experimental results met the designers' expectations, indicating that the proposed hardware represents a viable solution for a wide range of high performance building automation systems design and development.
The cell-based structure, which makes up the majority of biological organisms, offers the ability to grow with fault-tolerance abilities and selfrepair. By adapting these mechanisms and capabilities to nature, scientific approaches have promoted research for understanding related phenomena and associated principles to engine complex novel digital systems and improve their capability. Founded by these observations, the paper is focused on computeraided modeling, simulation and experimental research of embryonic systems, with the purpose to implement very large scale integrated hardware structures which are able to imitate cells or artificial organism operation mode, with similar robustness and fault-tolerance properties like their biological equivalents from nature. Field Programmable Gate Array (FPGA)-based artificial cell model configuration provided with strongly network communication capabilities is proposed and developed. The presented theoretical and simulation approaches were tested on a laboratory prototype embryonic system (embryonic machine), for study and implementation of basic abilities of living organisms.
Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment.
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