Consensus of self-driven agents with avoidance of collisions

In recent years, many efforts have been addressed on collision avoidance of collectively moving agents. In this paper, we propose a modified version of the Vicsek model with adaptive speed, which can guarantee the absence of collisions. However, this strategy leads to an aggregated state with slowly moving agents. We therefore further introduce a certain repulsion, which results in both faster consensus and longer safe distance among agents, and thus provides a powerful mechanism for collective motions in biological and technological multi-agent systems.Comment: 8 figures, and 7 page

Accelerating consensus of self-driven swarm via adaptive speed

In resent years, Vicsek model has attracted more and more attention and been well developed. However, the in-depth analysis on the convergence time are scarce thus far. In this paper, we study some certain factors that mainly govern the convergence time of Vicsek model. By extensively numerical simulations, we find the convergence time scales in a power law with $r^2\ln N$ in the noise-free case, where $r$ and $N$ are horizon radius and the number of particles. Furthermore, to accelerate the convergence, we propose a new model in which the speed of each particle is variable. The convergence time can be remarkably shortened compared with the standard Vicsek model.Comment: 11 pages, 6 figure

Sublytic C5b-9 Induces Glomerular Mesangial Cell Apoptosis Through miR-3546/SOX4/Survivin Axis in Rat Thy-1 Nephritis

Background/Aims: The activation of complement system and the formation of C5b-9 complex have been confirmed in the glomeruli of patients with mesangioproliferative glomerulonephritis (MsPGN). However, the role and mechanism of C5b-9-induced injury in glomerular mesangial cell (GMC) are poorly understood. Rat Thy-1N is an animal model for studying MsPGN. It has been revealed that the attack of C5b-9 to the GMC in rat Thy-1N is sublytic, and sublytic C5b-9 can cause GMC apoptosis, but the underlying mechanism is not fully elucidated. To explore the role and regulatory mechanism of C5b-9 in MsPGN lesion, we used rat Thy-1N model and first detected the change of microRNA (miRNA) profiles both in Thy-1N rat renal tissues (in vivo) and in the cultured GMCs with sublytic C5b-9 stimulation (in vitro). Then we determined the effect of miR-3546, which increased both in vivo and in vitro, on GMC apoptosis upon sublytic C5b-9 as well as the involved mechanism. Methods: Rat Thy-1N model was established and GMCs were treated with sublytic C5b-9. The rat renal cortex and the stimulated GMCs were obtained for miRNA microarray detection. Subsequently, the increased miRNAs were verified by real-time PCR. Meanwhile, to ascertain the ability of some miRNAs to upregulate cleaved caspase 3 and induce GMC apoptosis, the corresponding miRNA mimics were transfected into GMCs, followed by western blotting (WB) and flow cytometry mesurement. Thereafter, the miR-3546-targeted gene (SOX4) was predicted using bioinformatics approaches, and SOX4 expression in Thy-1N tissues and in the GMCs upon sublytic C5b-9 stimulation or miR-3546 mimic/inhibitor transfection were detected using real-time PCR and WB. To prove that miR-3546 can affect SOX4 gene transcription and SOX4 can regulate survivin expression, dual luciferase reporter assay, real-time PCR, WB and chromatin immunoprecipitation (ChIP) assays were performed. Furthermore, the role of miR-3546/SOX4/survivin axis in the GMC apoptosis induced by sublytic C5b-9 was examined using WB and flow cytometry. Results: Compared with normal renal tissues and untreated GMCs, there were 43 and 62 upregulated miRNAs (> 2-fold) in Thy-1N tissues and sublytic C5b-9-stimulated GMCs respectively. A total of 17 miRNAs were increased both in vivo and in vitro, 11 of which were validated by real-time PCR. Among them, miR-3546 could markedly promote GMC apoptosis and inhibit SOX4 or survivin expression in response to sublytic C5b-9, and either SOX4 or survivin overexpression markedly rescued the GMC apoptosis mediated by miR-3546 mimic. Additionally, SOX4 overexpression could reverse the survivin suppression by miR-3546 mimic, and SOX4 could bind to survivin promoter (-1,278 to -853 nt) and activate survivin gene transcription. Conclusion: MiR-3546/ SOX4/survivin axis has a promoting role in the GMC apoptosis triggered by sublytic C5b-9, and our findings may provide a new insight into the pathogenesis of rat Thy-1N and human MsPGN

Secreted protein Del-1 regulates myelopoiesis in the hematopoietic stem cell niche

Hematopoietic stem cells (HSCs) remain mostly quiescent under steady-state conditions but switch to a proliferative state following hematopoietic stress, e.g., bone marrow (BM) injury, transplantation, or systemic infection and inflammation. The homeostatic balance between quiescence, self-renewal, and differentiation of HSCs is strongly dependent on their interactions with cells that constitute a specialized microanatomical environment in the BM known as the HSC niche. Here, we identified the secreted extracellular matrix protein Del-1 as a component and regulator of the HSC niche. Specifically, we found that Del-1 was expressed by several cellular components of the HSC niche, including arteriolar endothelial cells, CXCL12-abundant reticular (CAR) cells, and cells of the osteoblastic lineage. Del-1 promoted critical functions of the HSC niche, as it regulated long-term HSC (LT-HSC) proliferation and differentiation toward the myeloid lineage. Del-1 deficiency in mice resulted in reduced LT-HSC proliferation and infringed preferentially upon myelopoiesis under both steady-state and stressful conditions, such as hematopoietic cell transplantation and G-CSF- or inflammation-induced stress myelopoiesis. Del-1-induced HSC proliferation and myeloid lineage commitment were mediated by β3 integrin on hematopoietic progenitors. This hitherto unknown Del-1 function in the HSC niche represents a juxtacrine homeostatic adaptation of the hematopoietic system in stress myelopoiesis

Modulation of Myelopoiesis Progenitors Is an Integral Component of Trained Immunity

Trained innate immunity fosters a sustained favorable response of myeloid cells to a secondary challenge, despite their short lifespan in circulation. We thus hypothesized that trained immunity acts via modulation of hematopoietic stem and progenitor cells (HSPCs). Administration of β-glucan (prototypical trained-immunity-inducing agonist) to mice induced expansion of progenitors of the myeloid lineage, which was associated with elevated signaling by innate immune mediators, such as IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF), and with adaptations in glucose metabolism and cholesterol biosynthesis. The trained-immunity-related increase in myelopoiesis resulted in a beneficial response to secondary LPS challenge and protection from chemotherapy-induced myelosuppression in mice. Therefore, modulation of myeloid progenitors in the bone marrow is an integral component of trained immunity, which to date, was considered to involve functional changes of mature myeloid cells in the periphery

Comparative analysis of ascorbate peroxidases (APXs) from selected plants with a special focus on Oryza sativa employing public databases.

Reactive oxygen species (ROS) are produced by plants. Hydrogen peroxide (H2O2) is one important component of ROS and able to modulate plant growth and development at low level and damage plant cells at high concentrations. Ascorbate peroxidase (APX) shows high affinity towards H2O2 and plays vital roles in H2O2-scavenging. In order to explore the differences of APXs from selected plant species, bioinformatics methods and public databases were used to evaluate the physicochemical properties, conserved motifs, potential modifications and cis-elements in all the APXs, and protein-protein network and expression profiles of rice APXs. The results suggested that APXs in the selected plant species showed high evolutionary conservation and were able to divide into seven groups, group I to VII. Members in the groups contained abundant phosphorylation sites. Interestingly, group I and VII had only PKC site. Additionally, promoters of the APXs contained abundant stress-related cis-elements. APXs in rice plant were able to interact with dehydroascorbate reductase 2. The eight APXs expressed differently in root, leaf, panicle, anther, pistil and seed. Drought, Pi-free, Cd and Xanthomonas oryzae pv. oryzicola B8-12 treatments were able to significantly alter the expression profiles of rice APXs. This study increases our knowledge to further explore functions and mechanisms of APXs and also guides their applications

Research on Method of Simulation Model Validation Based on Improved Grey Relational Analysis

AbstractSimulation model validation was one of the important contents in modeling and simulation technology. Traditional grey relational analysis method just considered data curves’ geometrical shape. Aiming at the limitation of traditional grey relational analysis, this paper proposed the improved grey relational analysis based on weighted linear. It took into account of data curves’ geometrical shape, similar degree of data value and decision-makers’ preference together. Therefore, it made the result more credible. The rationality and effectiveness of improved grey relational analysis were verified with example

Fault Diagnosis under Variable Working Conditions Based on STFT and Transfer Deep Residual Network

Fault diagnosis plays a very important role in ensuring the safe and reliable operations of machines. Currently, the deep learning-based fault diagnosis is attracting increasing attention. However, fault diagnosis under variable working conditions has been a significant challenge due to the domain discrepancy problem. This problem is also unavoidable in deep learning-based fault diagnosis methods. This paper contributes to the ongoing investigation by proposing a new approach for the fault diagnosis under variable working conditions based on STFT and transfer deep residual network (TDRN). The STFT was employed to convert vibration signal to time-frequency image as the input of the TDRN. To address the domain discrepancy problem, the TDRN was developed in this paper. Unlike traditional deep convolutional neural network (DCNN) methods, by combining with transfer learning, the TDRN can make a bridge between two different working conditions, thereby using the knowledge learned from a working condition to achieve a high classification accuracy in another working condition. Moreover, since the residual learning is introducing, the TDRN can overcome the problems of training difficulty and performance degradation existing in traditional DCNN methods, thus further improving the classification accuracy. Experiments are conducted on the popular CWRU bearing dataset to validate the effectiveness and superiority of the proposed approach. The results show that the developed TDRN outperforms those methods without transfer learning and/or residual learning in terms of the accuracy and feature learning ability for the fault diagnosis under variable working conditions