Modeling and optimization of adaptive foraging in swarm robotic systems

Understanding the effect of individual parameters on the collective performance of swarm robotic systems in order to design and optimize individual robot behaviors is a significant challenge. In this paper we present a macroscopic probabilistic model of adaptive collective foraging in a swarm of robots, where each robot in the swarm is capable of adjusting its time threshold parameters following the rules described by Liu et al. 2007. The swarm adapts the ratio of foragers to resters (division of labor) in order to maximize the net swarm energy for a given food density. A probabilistic finite state machine (PFSM) and a number of difference equations are developed to describe collective foraging at a macroscopic level. To model adaptation we introduce the new concepts of the sub-PFSM and private/public time thresholds. The model has been validated extensively with simulation trials, and results show that the model achieves very good accuracy in predicting the group performance of the swarm. Finally, a real-coded genetic algorithm is used to explore the parameter spaces and optimize the parameters of the adaptation algorithm. Although this paper presents a macroscopic probabilistic model for adaptive foraging, we argue that the approach could be applied to any adaptive swarm system in which the heterogeneity of the system is coupled with its time parameters

Involvement of Mast Cells in the Pathophysiology of Pain

Mast cells (MCs) are immune cells and are widely distributed throughout the body. MCs are not only classically viewed as effector cells of some allergic diseases but also participate in host defense, innate and acquired immunity, homeostatic responses, and immunoregulation. Mounting evidence indicates that activation of MCs releasing numerous vasoactive and inflammatory mediators has effects on the nervous system and has been involved in different pain conditions. Here, we review the latest advances made about the implication of MCs in pain. Possible cellular and molecular mechanisms regarding the crosstalk between MC and the nervous system in the initiation and maintenance of pain are also discussed

Adaptive foraging for simulated and real robotic swarms: The dynamical response threshold approach

Developing self-organised swarm systems capable of adapting to environmental changes as well as to dynamic situations is a complex challenge. An efficient labour division model, with the ability to regulate the distribution of work among swarm robots, is an important element of this kind of system. This paper extends the popular response threshold model and proposes a new adaptive response threshold model (ARTM). Experiments were carried out in simulation and in real-robot scenarios with the aim of studying the performance of this new adaptive model. Results presented in this paper verify that the extended approach improves on the adaptability of previous systems. For example, by reducing collision duration among robots in foraging missions, our approach helps small swarms of robots to adapt more efficiently to changing environments, thus increasing their self-sustainability (survival rate). Finally, we propose a minimal version of ARTM, which is derived from the conclusions drawn through real-robot and simulation results

Open-hardware e-puck Linux extension board for experimental swarm robotics research

In this paper we describe the implementation of a Linux extension board for the e-puck educational mobile robot, designed to enhance the computation, memory and networking performance of the robot at very low cost. The extension board is based on a 32-bit ARM9 microprocessor and provides wireless network support. The ARM9 extension board runs in parallel with the dsPIC microprocessor on the e-puck motherboard with communication between the two via an SPI bus. The extension board is designed to handle computationally intensive image processing, wireless communication and high-level intelligent robot control algorithms, while the dsPIC handles low-level sensor interfacing, data processing and motor control. The extension board runs an embedded Linux operating system, along with a Debian-based port of the root file system stored in a Micro SD card. The extended e-puck robot platform requires minimal effort to integrate the well-known open-source robot control framework Player and, when placed within a TCP/IP networked infrastructure, provides a powerful and flexible platform for experimental swarm robotics research. © 2010 Elsevier B.V. All rights reserved

Advanced liposome-loaded scaffolds for therapeutic and tissue engineering applications

Liposome is one of the most commonly used drug delivery systems in the world, due to its excellent biocompatibility, satisfactory ability in controlling drug release, and passive targeting capability. However, some drawbacks limit the application of liposomes in clinical, such as problems in transporting, storing, and difficulties in maintaining the drug concentration in the local area. Scaffolds usually are used as implants to supply certain mechanical supporting to the defective area or utilized as diagnosis and imaging methods. But, in general, unmodified scaffolds show limited abilities in promoting tissue regeneration and treating diseases. Therefore, liposome-scaffold composite systems are designed to take advantages of both liposomes’ biocompatibility and scaffolds’ strength to provide a novel system that is more suitable for clinical applications. This review introduces and discusses different types of liposomes and scaffolds, and also the application of liposome-scaffold composite systems in different diseases, such as cancer, diabetes, skin-related diseases, infection and human immunodeficiency virus, and in tissue regeneration like bone, teeth, spinal cord and wound healing.Peer reviewe

SIPA1 Is a modulator of HGF/MET induced tumour metastasis via the regulation of tight junction-based cell to cell barrier function

Background: Lung cancer is the leading cause of cancer death. SIPA1 is a mitogen induced GTPase activating protein (GAP) and may hamper cell cycle progression. SIPA1 has been shown to be involved in MET signaling and may contribute to tight junction (TJ) function and cancer metastasis. Methods: Human lung tumour cohorts were analyzed. In vitro cell function assays were performed after knock down of SIPA1 in lung cancer cells with/without treatment. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to analyze expression of HGF (hepatocyte growth factor), MET, and their downstream markers. Immunohistochemistry (IHC) and immunofluorescence (IFC) staining were performed. Results: Higher expression of SIPA1 in lung tumours was associated with a poorer prognosis. Knockdown of SIPA1 decreased invasiveness and proliferation of in vitro cell lines, and the SIPA1 knockdown cells demonstrated leaky barriers. Knockdown of SIPA1 decreased tight junction-based barrier function by downregulating MET at the protein but not the transcript level, through silencing of Grb2, SOCS, and PKCμ (Protein kinase Cµ), reducing the internalization and recycling of MET. Elevated levels of SIPA1 protein are correlated with receptor tyrosine kinases (RTKs), especially HGF/MET and TJs. The regulation of HGF on barrier function and invasion required the presence of SIPA1. Conclusions: SIPA1 plays an essential role in lung tumourigenesis and metastasis. SIPA1 may be a diagnostic and prognostic predictive biomarker. SIPA1 may also be a potential therapeutic target for non-small cell lung cancer (NSCLC) patients with aberrant MET expression and drug resistance

Distribution and colocalization of melatonin 1a-receptor and NADPH-d in the trigeminal system of rat

Melatonin and nitric oxide (NO) are involved in orofacial signal processing in the trigeminal sensory system. The aim of the present study was to examine the distribution of melatonin 1a-receptor (MT1) and its colocalization with nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in the spinal trigeminal nucleus (STN), the trigeminal ganglion (TG), and the mesencephalic trigeminal nucleus (MTN) in the rat, using histochemistry and immunohistochemistry. Our results show that MT1-positive neurons are widely distributed in the TG and the subnucleus caudalis of the STN. Furthermore, we found that MT1 colocalizes with NADPH-d throughout the TG and MTN, most extensively in the TG. The distribution pattern of MT1 and its colocalization with NADPH-d indicate that melatonin might play an important role in the trigeminal sensory system, which could be responsible for the regulation of NO levels