SECONDARY METABOLITES FROM RICE CULTURE OF ASPERGILLUS SP. ISOLATED FROM MELALEUCA SUBULATA (CHEEL) CRAVEN LEAVES AND THEIR ANTICANCER ACTIVITY

Objective: Aspergillus fungus is a rich source of natural products with broad biological activities. This study was conducted to identify secondary metabolites from the rice culture of Aspergillus species isolated from Melaleuca subulata leaves and evaluated their anticancer activity. Methods: Ethyl acetate extract was fractionated on silica gel and Sephadex columns. Structures of the compounds were established using physical and chemical methods. Cytotoxic activities of the extract and pure compounds against two human cancer cell lines (Mcf-7and Hep G2) were evaluated using microculture tetrazolium assay as well as the mode of the cytotoxicity was evaluated. Molecular docking studies have been performed using the Hsp 90 enzyme as an anticancer target. Results: Methyl linoleate (1), arugosin C (2), ergosterol (3), sterigmatocystin (4), diorcinol (5), alternariol-5-O-methyl ether (6), averufin (7), averufanin (8), and alternariol (9) were identified from ethyl acetate extract. All tested compounds exhibit week activity against MCF-7 and Hep G2 cell lines but a mixture of compounds 7 and 8 is considered to be more active towards both MCF-7 and Hep G 2 in comparison to other compounds. Compound 4 exhibits moderate activity against Hep G2 only as well as the ethyl acetate extract exerts moderate activity against MCF-7 cell line Moreover, compound 4 and a mixture of 7 and 8 caused a decrease in the number of Hep G2 cancer cells due to apoptotic and necrotic processes. Most active anticancer candidates 7 and 8 showed binding to the active site similar to geldanamycin reference ligand. Conclusion: Secondary metabolites identified from Aspergillus sp. and their anticancer activity were evaluated. Molecular docking suggested active candidates as Hsp 90 inhibitors

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations : design, characterisation, toxicity and transcorneal permeation studies

This study was aimed at preparing, characterising and evaluating in situ gel formulations based on a blend of two hydrophilic polymers i.e. poloxamer 407 (P407) and poloxamer 188 (P188) for a sustained ocular delivery of ketorolac tromethamine (KT). Drug-polymer interaction studies were performed using {DSC} and FT-IR. The gelation temperature (Tsol-gel), gelation time, rheological behaviour, mucoadhesive characteristics of these gels, transcorneal permeation and ocular irritation as well as toxicity was investigated. {DSC} and FT-IR studies revealed that there may be electrostatic interactions between the drug and the polymers used. {P188} modified the Tsol/gel of {P407} bringing it close to eye temperature (35°C) compared with the formulation containing {P407} alone. Moreover, gels that comprised {P407} and {P188} exhibited a pseudoplastic behaviour at different concentrations. Furthermore, mucoadhesion study using mucin discs showed that in situ gel formulations have good mucoadhesive characteristics upon increasing the concentration of P407. When comparing formulations {PP11} and PP12, the work of adhesion decreased significantly (P < 0.001) from 377.9 ± 7.79 mN.mm to 272.3 ± 6.11 mN.mm. In vitro release and ex vivo permeation experiments indicated that the in situ gels were able to prolong and control {KT} release as only 48 of the {KT} released within 12 h. In addition, the HET-CAM and {BCOP} tests confirmed the non-irritancy of {KT} loaded in situ gels, and HET-CAM test demonstrated the ability of ocular protection against strongly irritant substances. {MTT} assay on primary corneal epithelial cells revealed that in situ gel formulations loaded with {KT} showed reasonable and acceptable percent cell viability compared with control samples

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Neural inverse reinforcement learning in autonomous navigation

International audienc

Virtual traffic simulation with neural network learned mobility model.

International audienceVirtual traffic simulation plays an important role in easing traffic congestion and reducing traffic pollution. As the transportation network expands, the former rule-based mobility models showed several limitations in producing convincing virtual vehicles. A more realistic model with example-based method is in demand. In this paper, a neural network is employed with carefully selected traffic trajectory data. The virtual vehicle production is driven by the proposed mobility model and organized by a specified structure. Then, the virtual traffic simulation could be given for an indicated scenario

Contribution to intelligent vehicle platoon control

Ce mémoire est consacré à la mise en œuvre de commandes d'un train de véhicules intelligents sur autoroute ayant pour objectifs principaux de réduire la congestion et d améliorer la sécurité routière. Après avoir présenté l'état de l'art sur des systèmes de conduite automatisée, des modèles de la dynamique longitudinale et latérale du véhicule sont présentés. Ensuite, des stratégies de contrôle longitudinal et latéral sont étudiées.D'abord, le contrôle longitudinal est conçu pour être hiérarchique avec un contrôleur de niveau supérieur et un contrôleur de niveau inférieur. Pour celui de niveau supérieur, une régulation d'inter-distance SSP (Safety Spacing Policy) est proposée. Nous avons constaté que la SSP peut assurer la stabilité de la chaîne et la stabilité des flux de trafic et augmenter ainsi la capacité de trafic. Puis, pour celui de niveau inférieur, une loi de commande floue coordonnée est proposée pour gérer l'accélérateur et le freinage. Ensuite, une loi de commande multi-modèle floue est conçue pour le contrôle latéral. De plus, pour réaliser des transformations lisses entre les différentes opérations latérales, une architecture de contrôle hiérarchique est proposée. Puis, l'intégration des commandes longitudinale et latérale est étudiée. Enfin, l'estimation des variables d états du véhicule est discutée. Un filtre de Kalman-Bucy est conçu pour estimer les états du véhicule. En outre, un prototype de véhicule intelligent à échelle réduite est également présenté. Les performances des divers algorithmes de commande proposés ont été testées par simulations, et les résultats ont été confirmés par les premières expériences en utilisant le prototypeThis PhD thesis is dedicated to the control strategies for intelligent vehicle platoon in highway with the main aims of alleviating traffic congestion and improving traffic safety. After a review of the different existing automated driving systems, the vehicle longitudinal and lateral dynamic models are derived. Then, the longitudinal control and lateral control strategies are studied respectively. At first, the longitudinal control system is designed to be hierarchical with an upper level controller and a lower level controller. For the upper level controller, a safety spacing policy (SSP) is proposed. It is shown that the proposed SSP can ensure string stability, traffic flow stability and improve traffic capacity. Then, a coordinated throttle and brake fuzzy controller (lower level controller) is designed, in which a logic switch is designed to coordinate the two actuators (throttle and brake pedals). Second, for the lateral control, a multi-model fuzzy controller is designed. And a hierarchical lateral control architecture is also proposed, which can effectuate flexible switch between different lateral operations. After that, the integration of the longitudinal controller and lateral controller is also studied. Finally, the estimation of vehicle states is discussed. A Kalman-Bucy filter is designed to estimate vehicle states in lateral dynamics. Moreover, a reduced scale multi-sensor intelligent vehicle prototype is also presented. The performances of the divers control algorithms proposed in this thesis have been tested in numerical simulations, and the first step experiments with the reduced scale vehicle prototype gave encouraging resultsVILLENEUVE D'ASCQ-ECLI (590092307) / SudocSudocFranceF

V2X-Based Decentralized Cooperative Adaptive Cruise Control in the Vicinity of Intersections

International audienceCooperative driving with V2X communication is widely researched due to its considerable potential to improve the safety and efficiency of road transportation systems. In this paper, a decentralized cooperative adaptive cruise control algorithm using V2X for vehicles in the vicinity of intersections (CACC-VI) is proposed. This algorithm is designed to improve the throughput of intersection by reorganizing the vehicle platoons around it, in consideration of safety, fuel consumption, speed limit, heterogeneous features of vehicles, and passenger comfort. Within a platoon, vehicles try to find the optimal control input by a distributed particle swarm optimization (PSO) algorithm, in order to reduce tracking errors, while respecting different constraints. A concept of opportunity space is proposed to facilitate platoon reorganization, in which a subplatoon or an individual vehicle can choose to accelerate to join in the preceding platoon or to decelerate to depart from the current one. The main idea is to make full use of the road capacity and to distribute it to most vehicles that are capable to find an accelerating trajectory to get through the intersection within a limited period. The originality of our algorithm is the introduction of a novel application of V2X communication to make the traffic more intelligent, in terms of safety, time saving, and environment friendly

Virtual reality platform design & development for intelligent vehicles control

Cette thèse est consacrée au domaine interdisciplinaire des Systèmes de Transport Intelligents et des technologies de Réalité Virtuelle. Elle se concentre sur l amélioration des stratégies de commande des véhicules intelligents en tenant compte des impacts de l environnement naturel ainsi que sur l analyse de performance, la visualisation et la vérification de la validité des algorithmes de commande sur la plateforme de véhicules intelligents réalité virtuelle (IVVR).La plateforme IVVR comprend trois sous-systèmes : un sous-système de commande de véhicules intelligents, un sous-système de visualisation et un sous-système virtuel sans fil. Le synthétique environnement naturel a été modélisé et simulé pour la simulation et l analyse de performance des stratégies de commande sous conditions environnementales complexes. Ensuite, les expérimentations concernant le trafic équipé du régulateur de vitesses adaptatives (ou coopérative) sont exécutés et ils montrent que les systèmes existants ont échoué à maintenir une espace inter-véhiculaire de sécurité lorsque les conditions d environnement naturel sont défavorables. Dans ce cas, nous proposons un nouvel algorithme de commande appelé NECACC pour le contrôle longitudinal du véhicule en maintenant une espace inter-véhiculaire de sécurité et garantissant une capacité de circulation optimisée même dans des conditions environnementales complexes. Cet algorithme est ensuite simulé, vérifié et validé sur la plateforme IVVR. Enfin, les démonstrations de trafic virtuel effectuant des manœuvres communes de circulation contrôlés par les systèmes de commande intégrés proposées sont présentées sous diverse conditions environnementalesThis thesis is dedicated to the interdisciplinary area of Intelligent Transportation Systems and Virtual Reality technologies. It focuses on the improvement of intelligent vehicles control strategies by considering the natural environment impacts as well as the visualization, the verification and performance analysis of proposed control algorithms on the proposed Intelligent Vehicles Virtual Reality (IVVR) platform.The IVVR platform includes three subsystems: Vehicle Intelligent Control Subsystem, Visualization Subsystem and Virtual Wireless Subsystem. For realizing the control strategy simulation and performance analysis under complex natural environment conditions, Synthetic Natural Environment has been modeled and simulated in this IVVR platform. Therefore, experiments of Adaptive Cruise Control (ACC) or Cooperative ACC system equipped traffic are executed and show that normal ACC/CACC system fails to keep a safe inter-vehicle space when the natural environment condition is variable or adverse especially in stiff conditions. For solving this problem, we propose a new control algorithm called NECACC (Natural Environment based CACC) for longitudinal vehicle control in maintaining a safe inter-vehicle distance as well as guaranteeing an appropriate traffic capacity even under complex environmental conditions. This algorithm is then simulated and verified in IVVR platform as a proof of concept . Finally, some virtual traffic demonstrations performing common traffic maneuvers are presented in IVVR platform under various environmental conditions. The vehicle platoon is controlled by proposed integrated control system and the safety can be ensured all the timeVILLENEUVE D'ASCQ-ECLI (590092307) / SudocSudocFranceF