A Swarm Robotic Approach to Inspection of 2.5 D Surfaces in Orbit

Robotic inspection offers a robust, scalable, and flexible alternative to deploying fixed sensor networks or humaninspectors. While prior work has mostly focused on single robot inspections, this work studies the deployment of a swarm ofinspecting robots on a simplified surface of an in-orbit infrastructure. The robots look for points of mechanical failure and inspectthe surface by assessing propagating vibration signals. In particular, they measure the magnitude of acceleration they sense ateach location on the surface. Our choice for sensing and analyzing vibration signals is supported by the established position ofvibration analysis methods in industrial infrastructure health assessment. We perform simulation studies in Webots, a physicsbased robotic simulator, and present a distributed inspection algorithm based on bio-inspired particle swarm optimization andevolutionary algorithm niching techniques to collectively localize an a priori unknown number of mechanical failure points. Toperform the vibration analysis and obtain realistic acceleration data, we use the ANSYS multi-physics simulation software andmodel mechanical failure points as vibration sources on the surface. We deploy a robot swarm comprising eight robots of 10-cmsize that use a bio-inspired inchworming locomotion pattern. The swarm is deployed on 2.5D (that is curved 2D) cylindricalsurfaces with and without obstacles to investigate the robustness of the algorithm in environments with varying geometric complexity. We study three performance metrics: (1) proximity of the localized sources to their ground truth locations, (2) time tolocalize each source, and (3) time to finish the inspection task given an 80% surface coverage threshold. Our results show thatthe robots accurately localize all the failure sources and reach the coverage threshold required to complete the inspection. Thiswork demonstrates the viability of deploying robot swarms for inspection of potentially complex 3D environments.<br/

An Approach Based on Particle Swarm Optimization for Inspection of Spacecraft Hulls by a Swarm of Miniaturized Robots

The remoteness and hazards that are inherent to the operating environments of space infrastructures promote their need for automated robotic inspection. In particular, micrometeoroid and orbital debris impact and structural fatigue are common sources of damage to spacecraft hulls. Vibration sensing has been used to detect structural damage in spacecraft hulls as well as in structural health monitoring practices in industry by deploying static sensors. In this paper, we propose using a swarm of miniaturized vibration-sensing mobile robots realizing a network of mobile sensors. We present a distributed inspection algorithm based on the bio-inspired particle swarm optimization and evolutionary algorithm niching techniques to deliver the task of enumeration and localization of an a priori unknown number of vibration sources on a simplified 2.5D spacecraft surface. Our algorithm is deployed on a swarm of simulated cm-scale wheeled robots. These are guided in their inspection task by sensing vibrations arising from failure points on the surface which are detected by on-board accelerometers. We study three performance metrics: (1) proximity of the localized sources to the ground truth locations, (2) time to localize each source, and (3) time to finish the inspection task given a 75% inspection coverage threshold. We find that our swarm is able to successfully localize the present so

Luteolin triggers global changes in the microglial transcriptome leading to a unique anti-inflammatory and neuroprotective phenotype

<p>Abstract</p> <p>Background</p> <p>Luteolin, a plant derived flavonoid, exerts a variety of pharmacological activities and anti-oxidant properties associated with its capacity to scavenge oxygen and nitrogen species. Luteolin also shows potent anti-inflammatory activities by inhibiting nuclear factor kappa B (NFkB) signaling in immune cells. To better understand the immuno-modulatory effects of this important flavonoid, we performed a genome-wide expression analysis in pro-inflammatory challenged microglia treated with luteolin and conducted a phenotypic and functional characterization.</p> <p>Methods</p> <p>Resting and LPS-activated BV-2 microglia were treated with luteolin in various concentrations and mRNA levels of pro-inflammatory markers were determined. DNA microarray experiments and bioinformatic data mining were performed to capture global transcriptomic changes following luteolin stimulation of microglia. Extensive qRT-PCR analyses were carried out for an independent confirmation of newly identified luteolin-regulated transcripts. The activation state of luteolin-treated microglia was assessed by morphological characterization. Microglia-mediated neurotoxicity was assessed by quantifying secreted nitric oxide levels and apoptosis of 661W photoreceptors cultured in microglia-conditioned medium.</p> <p>Results</p> <p>Luteolin dose-dependently suppressed pro-inflammatory marker expression in LPS-activated microglia and triggered global changes in the microglial transcriptome with more than 50 differentially expressed transcripts. Pro-inflammatory and pro-apoptotic gene expression was effectively blocked by luteolin. In contrast, mRNA levels of genes related to anti-oxidant metabolism, phagocytic uptake, ramification, and chemotaxis were significantly induced. Luteolin treatment had a major effect on microglial morphology leading to ramification of formerly amoeboid cells associated with the formation of long filopodia. When co-incubated with luteolin, LPS-activated microglia showed strongly reduced NO secretion and significantly decreased neurotoxicity on 661W photoreceptor cultures.</p> <p>Conclusions</p> <p>Our findings confirm the inhibitory effects of luteolin on pro-inflammatory cytokine expression in microglia. Moreover, our transcriptomic data suggest that this flavonoid is a potent modulator of microglial activation and affects several signaling pathways leading to a unique phenotype with anti-inflammatory, anti-oxidative, and neuroprotective characteristics. With the identification of several novel luteolin-regulated genes, our findings provide a molecular basis to understand the versatile effects of luteolin on microglial homeostasis. The data also suggest that luteolin could be a promising candidate to develop immuno-modulatory and neuroprotective therapies for the treatment of neurodegenerative disorders.</p

Mass and Magnetic Moments of the Heavy Flavored Baryons with J=3/2J=3/2 in Light Cone QCD Sum Rules

Inspired by the results of recent experimental discoveries for charm and bottom baryons, the masses and magnetic moments of the heavy baryons with $J^P=3/2^+$ containing a single heavy quark are studied within light cone QCD sum rules method. Our results on the masses of heavy baryons are in good agreement with predictions of other approaches, as well as with the existing experimental values. Our predictions on the masses of the states, which are not yet discovered in the experiments, can be tested in the future experiments. A comparison of our results on the magnetic moments of these baryons and the hyper central model predictions is presented.Comment: 33 Pages, 16 Figures and 3 Table

First steps Toward Ultrasound-Based Motion compensation for imaging and Therapy: calibration with an Optical system and 4D PeT imaging

Target motion, particularly in the abdomen, due to respiration or patient movement is still a challenge in many diagnostic and therapeutic processes. Hence, methods to detect and compensate this motion are required. Diagnostic ultrasound (US) represents a non-invasive and dose-free alternative to fluoroscopy, providing more information about internal target motion than respiration belt or optical tracking. The goal of this project is to develop an US-based motion tracking for real-time motion correction in radiation therapy and diagnostic imaging, notably in 4D positron emission tomography (PET). In this work, a workflow is established to enable the transformation of US tracking data to the coordinates of the treatment delivery or imaging system - even if the US probe is moving due to respiration. It is shown that the US tracking signal is equally adequate for 4D PET image reconstruction as the clinically used respiration belt and provides additional opportunities in this concern. Furthermore, it is demonstrated that the US probe being within the PET field of view generally has no relevant influence on the image quality. The accuracy and precision of all the steps in the calibration workflow for US tracking-based 4D PET imaging are found to be in an acceptable range for clinical implementation. Eventually, we show in vitro that an US-based motion tracking in absolute room coordinates with a moving US transducer is feasible

Toxicity of three types of arsenolipids : species-specific effects in Caenorhabditis elegans

This work was supported by the German Research Foundation (DFG), grant number SCHW 903/10-1 and the Austrian Science Fund (FWF), project number I2412-B21. MA was supported in part by grants from the NIEHS, R01ES10563 and R0107331.Peer reviewedPostprin