Monocular depth estimation for 2D mapping of simulated environments

This article addresses the problem of constructing maps for 2D simulated environments. An algorithm based on monocular depth estimation is proposed achieving comparable accuracy to methods utilizing expensive sensors such as RGBD cameras and LIDARs. To solve the problem, we employ a multi-stage approach. First, a neural network predicts a relative disparity map from an RGB flow provided by RGBD camera. Using depth measurements from the same camera, two parameters are estimated that connect the relative and absolute displacement maps in the form of a linear regression relation. Based on a simpler RGB camera, by applying a neural network and estimates of scaling parameters, an estimate of the absolute displacement map is formed, which allows to obtain an estimate of the depth map. Thus, a virtual scanner has been designed providing Cartographer SLAM with depth information for environment mapping. The proposed algorithm was evaluated on a ROS 2.0 simulation of a simple mobile robot. It achieves faster depth prediction compared to other depth estimation algorithms. Furthermore, maps generated by our approach demonstrated a high overlap ratio with those obtained using an ideal RGBD camera. The proposed algorithm can find applicability in crucial tasks for mobile robots, like obstacle avoidance, and path planning. Moreover, it can be used to generate accurate cost maps, enhancing safety and adaptability in mobile robot navigation

The Role of Mislocalized Phototransduction in Photoreceptor Cell Death of Retinitis Pigmentosa

Most of inherited retinal diseases such as retinitis pigmentosa (RP) cause photoreceptor cell death resulting in blindness. RP is a large family of diseases in which the photoreceptor cell death can be caused by a number of pathways. Among them, light exposure has been reported to induce photoreceptor cell death. However, the detailed mechanism by which photoreceptor cell death is caused by light exposure is unclear. In this study, we have shown that even a mild light exposure can induce ectopic phototransduction and result in the acceleration of rod photoreceptor cell death in some vertebrate models. In ovl, a zebrafish model of outer segment deficiency, photoreceptor cell death is associated with light exposure. The ovl larvae show ectopic accumulation of rhodopsin and knockdown of ectopic rhodopsin and transducin rescue rod photoreceptor cell death. However, knockdown of phosphodiesterase, the enzyme that mediates the next step of phototransduction, does not. So, ectopic phototransduction activated by light exposure, which leads to rod photoreceptor cell death, is through the action of transducin. Furthermore, we have demonstrated that forced activation of adenylyl cyclase in the inner segment leads to rod photoreceptor cell death. For further confirmation, we have also generated a transgenic fish which possesses a human rhodopsin mutation, Q344X. This fish and rd10 model mice show photoreceptor cell death caused by adenylyl cyclase. In short, our study indicates that in some RP, adenylyl cyclase is involved in photoreceptor cell death pathway; its inhibition is potentially a logical approach for a novel RP therapy

Risks and Remedies in ISRA University e-Learning System

Information technology brought radical changes in various aspects of contemporary life and education sector in general and in higher education particularly. Our institute (Isra University) decided to be more responsive to these dramatic changes and rapid developments and effectively employ information technology and modern communications to improve the quality of teaching and learning through a gradual shift from web-enhanced courses towards blended learning, distance learning, and open learning to achieve better learning outcomes excellence and competition. Our institution uses Moodle system to offer web-enhanced courses with timed on-line quizzes as well as a vehicle for students to submit homework assignments and gain access to different course related resources. Isra university e-learning center (IUELC) investigated the risks at Isra university e-learning system (IUELS) may encounter at this level of offering web-enhanced courses and the suitable solutions to these risks. This paper outlines the identified risks (IUELS-risks) and their remedies (IUELS-remedies)

Risks and Remedies in ISRA University e-Learning System

Information technology brought radical changes in various aspects of contemporary life and education sector in general and in higher education particularly. Our institute (Isra University) decided to be more responsive to these dramatic changes and rapid developments and effectively employ information technology and modern communications to improve the quality of teaching and learning through a gradual shift from web-enhanced courses towards blended learning, distance learning, and open learning to achieve better learning outcomes excellence and competition. Our institution uses Moodle system to offer web-enhanced courses with timed on-line quizzes as well as a vehicle for students to submit homework assignments and gain access to different course related resources. Isra university e-learning center (IUELC) investigated the risks at Isra university e-learning system (IUELS) may encounter at this level of offering web-enhanced courses and the suitable solutions to these risks. This paper outlines the identified risks (IUELS-risks) and their remedies (IUELS-remedies)

Risks and Remedies in ISRA University e-Learning System

Information technology brought radical changes in various aspects of contemporary life and education sector in general and in higher education particularly. Our institute (Isra University) decided to be more responsive to these dramatic changes and rapid developments and effectively employ information technology and modern communications to improve the quality of teaching and learning through a gradual shift from web-enhanced courses towards blended learning, distance learning, and open learning to achieve better learning outcomes excellence and competition. Our institution uses Moodle system to offer web-enhanced courses with timed on-line quizzes as well as a vehicle for students to submit homework assignments and gain access to different course related resources. Isra university e-learning center (IUELC) investigated the risks at Isra university e-learning system (IUELS) may encounter at this level of offering web-enhanced courses and the suitable solutions to these risks. This paper outlines the identified risks (IUELS-risks) and their remedies (IUELS-remedies)

Seed-mediated hot-injection synthesis of tiny Ag nanocrystals on nanoscale solid supports and reaction mechanism

Controlling the size and shape of noble Ag nanocrystals (NCs) is of great interest because of their unique size-and shape-dependent properties, especially below 20 nm, and because of interesting applications in drug delivery, sensing, and catalysis. However, the high surface energy and tendency of these tiny NCs to aggregate deteriorates their unique properties and limits their applications. to avoid the aggregation of Ag NCs and improve their performance, we report a. seed-mediated hot injection approach to synthesize highly dispersed tiny Ag NCs on a nanosized solid CaCO3 support. This simple, low-cost, and effective chemical approach allows for synthesizing highly uniform Ag NCs (similar to 10 nm) on the surface of presynthesized CaCO3 single NCs (similar to 52 nm) without any aggregation of the Ag NCs. Viscose fibers were coated with the Ag@CaCO3 composite nanoparticles (NPs) produced, as well as with similar to 426 nm Ag NPs for reference. The Ag@CaCO3 composite NPs show excellent UV protection and antibacterial activity against Escherichia coli. In addition, they give a satin sheen gold to a dark gold color to the viscose fibers, while the Ag NPs (similar to 426 nm) result in a silver color. The proposed synthesis approach is highly versatile and applicable for many other noble metals, like Au or Pt

Isocyanate free condensed tannin-based polyurethanes

International audienceCondensed flavonoid tannins from Maritime Pine (Pious pinaster), Mimosa (Acacia mearnsii), and Radiata Pine barks, and Quebracho (Schinopsis lorentzii and balansae) wood, were first reacted with dimethyl carbonate. Then hexamethylenediamine was added to these mixtures to form urethane linkages. The resulting materials were analyzed by Fourier transform infrared (FTIR) spectroscopy, matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). Finally the resulting analysis indicated that the products obtained are polyurethanes. Initial wood coating applications tests were carried out under conditions of higher temperature and some pressure, and the contact angle of the surface coatings so prepared was measured

Colored, photocatalytic, antimicrobial and UV-protected viscose fibers decorated with Ag/Ag2CO3 and Ag/Ag3PO4 nanoparticles

Surface modification of textile fibers with nanoparticles (NPs) has been widely investigated for multiple different uses. Herein, a simple and highly efficient technique was developed to impart multifunctional properties to viscose rayon fibers by in situ adding Ag/Ag2CO3 and Ag/Ag3PO4 NPs. Firstly, Ag2CO3 and Ag3PO4 NPs were precipitated via ultrasonic irradiation synthesis. Subsequently, Ag NPs were synthesized in situ by photoreduction of the excess Ag+ ions under UV-irradiation. The viscose rayon fibers decorated with Ag/Ag2CO3 and Ag/Ag3PO4 NPs showed excellent photocatalytic activity, and were protective against pathogenic microorganisms and UV radiation. Additionally, the modified viscose rayon fibers exhibited different colors ranging from pale yellow for Ag/Ag2CO3/viscose fibers to pale purple/violet for Ag/Ag3PO4/viscose fibers

Evaluation of the Morphological, Electrical and Antibacterial Properties of Polyaniline Nanocomposite Based on Zn/Al-Layered Double Hydroxides

International audienceIn this work, polyaniline (PAn) based on Zinc aluminum layered double hydroxides (3:1; Zn/Al-LDHs) nanocomposites; containing various concentrations of LDHs were successfully prepared via free emulsion polymerization using ammonium peroxydisulfate (APS) as an oxidizing agent. The morphology of the synthesized LDHs and its nanocomposites were investigated using transmission electron microscope (TEM), scanning electron microscope (SEM) and X-Ray diffraction (XRD). TEM and SEM results showed that LDHs nanoparticles were obviously located in the polymer, with good dispersion. While the XRD results were demonstrated intercalated or exfoliated nanocomposites morphologies depending on the modification of the LDHs. The surface area of the fashioned nanocomposites was investigated. It was found that the surface area for PAn/LDHs, PAn/LDH-DS and LDH-DBS nanocomposites increased to 34.26 m2 g−1, 36.83 m2 g−1and 36.62 m2 g−1, respectively, while neat polyaniline was (23.84 m2 g−1). Moreover, the electrical conductivity for the investigated nanocomposites was enhanced with increasing the ratio of LDHs in the prepared nanocomposite. The fashioned nanocomposites exhibited good antibacterial activity against G+ve, G−ve bacteria and fungi. Therefore, it could be a promising candidate in various electrical and biological applications