31 research outputs found
A Multi Agent Based Organizational Architecture for Dynamic Pickup and Delivery Problem
Pickup and Delivery Problem (PDP) consists of searching an optimal set of vehicles and an optimal set of routes, one route by each vehicle, in order to pickup items from a set of origins and deliver them to another set of destinations. Pickup and delivery problem is a class of complex systems whose complexity is NP Hard. In PDP real life applications, heuristics and meta heuristics methods are used in order to obtain an acceptable solution in reasonable execution time. When unpredictable events, like for example path cut and vehicles failure, may occur during the PDP schedule execution, we say that the PDP is dynamic (DPDP) and in this case we have to revise this schedule. In this paper, we propose a multi agent architecture for DPDP based on an organizational architecture. Supported by a formal framework, the proposed architecture allows us to show, through a case study that computed solution for the studied problem could be done in a parallel manner which attenuates substantially the problem complexity
Synthèse verte et caractérisation des nanoparticules de ZnO à l’aide d’extrait des feuilles de Phoenix dactylifera L et leur applications.
Les développements actuels des méthodes de synthèse, les nanomatériaux forment un champ
d'investigation de plus en plus intéressant et actif. Dans cette étude, des nanoparticules de l’oxyde de
zinc sous forme de poudre ont été obtenu par la synthèse verte utilisant l’extrait de feuilles de Phoenix
Dactylifera. L.
L'extrait des feuilles de Phoenix Dactylifera L a été utilisé en tant que réducteur des ions de zinc
pour l’élaboration des nanoparticules ZnO. En effet, pour améliorer la taille de ces NPs, nous nous
sommes basés sur l’étude de un seul paramètre : la concentration massique de l’acétate de zinc dans la
gamme de (0,2 à 1,0 g). Ensuite, les nanoparticules d'oxyde de zinc obtenu ont été caractérisées par les
techniques suivantes : UV-Vis, FT-IR, XRD et MEB. L'analyse UV-Vis montre une absorption
maximale à 275 nm liée à ZnO. Les spectres FT-IR présentent un faible pic à 673 et 559 cm-1 attribué à
la vibration du ZnO. DRX montre la bonne qualité cristalline du produit ZnO avec des pics très bien
définis sur les plans (002), (100) et (101) indexés comme une structure hexagonale (würtzite). La taille
des grains de nanoparticules de ZnO synthétisés sont comprises entre 13,58 et 16,66 nm. L'image MEB
montre que les NPs obtenues en général, ont une forme sphérique irrégulière. Enfin l’activité
antioxydant des NPs a été évaluée par les tests à savoir : CAT et DPPH
Gi/o-protein coupled receptors in the aging brain
Cells translate extracellular signals to regulate processes such as differentiation, metabolism and proliferation, via transmembranar receptors. G protein-coupled receptors (GPCRs) belong to the largest family of transmembrane receptors, with over 800 members in the human species. Given the variety of key physiological functions regulated by GPCRs, these are main targets of existing drugs. During normal aging, alterations in the expression and activity of GPCRs have been observed. The central nervous system (CNS) is particularly affected by these alterations, which results in decreased brain functions, impaired neuroregeneration, and increased vulnerability to neuropathologies, such as Alzheimer's and Parkinson diseases. GPCRs signal via heterotrimeric G proteins, such as Go, the most abundant heterotrimeric G protein in CNS. We here review age-induced effects of GPCR signaling via the Gi/o subfamily at the CNS. During the aging process, a reduction in protein density is observed for almost half of the Gi/o-coupled GPCRs, particularly in age-vulnerable regions such as the frontal cortex, hippocampus, substantia nigra and striatum. Gi/o levels also tend to decrease with aging, particularly in regions such as the frontal cortex. Alterations in the expression and activity of GPCRs and coupled G proteins result from altered proteostasis, peroxidation of membranar lipids and age-associated neuronal degeneration and death, and have impact on aging hallmarks and age-related neuropathologies. Further, due to oligomerization of GPCRs at the membrane and their cooperative signaling, down-regulation of a specific Gi/o-coupled GPCR may affect signaling and drug targeting of other types/subtypes of GPCRs with which it dimerizes. Gi/o-coupled GPCRs receptorsomes are thus the focus of more effective therapeutic drugs aiming to prevent or revert the decline in brain functions and increased risk of neuropathologies at advanced ages.This work was supported by Fundação para a Ciência e
Tecnologia, Centro 2020 and Portugal 2020, the COMPETE
program, QREN, and the European Union (FEDER program)
via the GoBack project (PTDC/CVT-CVT/32261/2017),
the pAGE program (Centro-01-0145-FEDER-000003), and
Institute for Biomedicine iBiMED (UID/BIM/04501/2013;
UID/BIM/04501/2019).publishe