Red blood cell lingering modulates hematocrit distribution in the microcirculation

The distribution of red blood cells (RBCs) in the microcirculation determines the oxygen delivery and solute transport to tissues. This process relies on the partitioning of RBCs at successive bifurcations throughout the microvascular network, and it has been known since the last century that RBCs partition disproportionately to the fractional blood flow rate, therefore leading to heterogeneity of the hematocrit (i.e., volume fraction of RBCs in blood) in microvessels. Usually, downstream of a microvascular bifurcation, the vessel branch with a higher fraction of blood flow receives an even higher fraction of RBC flux. However, both temporal and time-average deviations from this phase-separation law have been observed in recent studies. Here, we quantify how the microscopic behavior of RBC lingering (i.e., RBCs temporarily residing near the bifurcation apex with diminished velocity) influences their partitioning, through combined in vivo experiments and in silico simulations. We developed an approach to quantify the cell lingering at highly confined capillary-level bifurcations and demonstrate that it correlates with deviations of the phase-separation process from established empirical predictions by Pries et al. Furthermore, we shed light on how the bifurcation geometry and cell membrane rigidity can affect the lingering behavior of RBCs; e.g., rigid cells tend to linger less than softer ones. Taken together, RBC lingering is an important mechanism that should be considered when studying how abnormal RBC rigidity in diseases such as malaria and sickle-cell disease could hinder the microcirculatory blood flow or how the vascular networks are altered under pathological conditions (e.g., thrombosis, tumors, aneurysm)

Consideration of long-run effects in choosing farming systems in Morocco

Les auteurs proposent une méthode d'analyse des facteurs environnementaux et socioéconomiques d'une région de bassins versants au Maroc. Les objectifs de cette méthode sont d'estimer : la possibilité d'adoption de nouvelles technologies proposées par les chercheurs et ses effets à cour et long terme sur les différentes exploitations et sur l'environnement; simuler des politiques d'incitation alternatives en faveur de l'adoption de ces technologies par les producteurs et d'évaluer les externalités de leur mise en palce. Les données utilisées dans cette étude proviennet des résultats d'une enquête réalisée à Boughergouh en 199

Clustering-based algorithm for connectivity maintenance in Vehicular Ad-Hoc Networks

International audienceAmong recent advances in wireless communication technologies' field, Vehicular Ad-hoc Networks (VANETs) have drawn the attention of both academic and industry researchers due to their potential applications including driving safety, entertainment, emergency applications, and content sharing. VANET networks are characterized by their high mobile topology changes. Clustering is one of the control schemes used to make this global topology less dynamic. It allows the formation of dynamic virtual backbone used to organize the medium access, to support quality of service and to simplify routing. Mainly, nodes are organized into clusters with at least one cluster head (CH) node that is responsible for the coordination tasks of its cluster. In this sight, our paper introduces a clustering mechanism based for connectivity maintenance in VANET. The proposed solution is experimentally evaluated using NS2 simulator

Comparative Study on the Total Phenolics, Total Flavonoids, and Biological Activities of <i>Papaver rhoeas</i> L. Extracts from Different Geographical Regions of Morocco

In this research, a comparative analysis was carried out to characterize the content of phenolics and biological activities of the whole plant of Papaver rhoeas L. (P. rhoeas) from different geographical regions of Morocco, as well as to determine the synergistic antimicrobial and antioxidant effects of all parts of P. rhoeas. The determination of total polyphenol content (TPC), total flavonoid content (TFC), and total anthocyanin content (TA) in extracts of whole plants of P. rhoeas from three different geographical regions: Taounate (P1E), Fez (P2E), and Sefrou (P3E) were estimated by the Folin–Ciocalteu reaction, the aluminum trichloride method and the differential pH absorption technique, respectively. Two tests were used to evaluate the antioxidant power of our samples: the DPPH test and the TAC test. Using two methods, disk diffusion and microdilution, antimicrobial activity was studied against four pathogenic bacteria and one yeast. The results of TPC, TFC, and TA show that the P3E sample is the richest in polyphenols, flavonoids, and anthocyanins, with values 37.33 ± 1.307 mg GAE/g, 4.72 ± 0.346 QE/g, and 1.77 ± 0.026 CGE/g, respectively. In addition, P3E showed the best antioxidant activity with an IC50 = 0.27 ± 0.001 mg/mL and TAC = 9.99 ± 0.768 mg AAE/g, respectively. The results of antimicrobial activity showed significant activity on almost all the tested strains. The lowest MIC was recorded for P3E against E. coli ATCC 25922 and E. coli CIP 53126 strains at 0.78 and 0.78 mg/mL, respectively. These results show that the geographical region can influence the plant’s phytochemistry and then these biological activities

Field Study and Chemical Analysis of Plant Waste in the Fez-Meknes Region, Morocco

Throughout the entire world, the biomass plant remains an important source of renewable energy. However, in Morocco, the energy recovery of this biomass is little or badly exploited compared to other solar, hydraulic, and wind resources. The aim of this study is to know the extent to which Moroccan companies are involved in the valorization of green waste and to identify among the latter those that have great energy and industrial value. The field investigation was carried out with the use of a questionnaire to different sectors of activity. The chemical analyses of the waste samples were carried out by different methods: Van Soest to investigate the fiber content, dinitrosalicylic acid and phenol-sulfuric acid to determine sugars, while the Folin&ndash;Ciocalteu method was employed for the determination of phenolic compounds. These are the ASTM standard methods to determine elemental, proximate composition, and calorific value (CV). The results of this survey showed that solid vegetable waste is diverse and represents 68.4% of the total green waste, of which 98% is not treated. Moreover, the chemical analysis displayed that forestry waste (FW), extracted parts wastes (EPW), and unused parts wastes (UPW) of medicinal and aromatic plants have high contents of cellulose (respectively 34.75, 48.44, and 54.19%) and hemicelluloses (28.44, 27.19 and 28.50%) and containing low amounts of lignin and phenolic compounds compared to olive waste (OW), olive pomace (OP), and household waste (HW). Almost all biomass wastes, except HW, have a low moisture (&lt;12%), ash content less than 5.1%, a significant percentage of C and H, and CV between 14.5 and 21.6 MJ/Kg. The PCA analysis showed a discrepancy in terms of components between the set formed by FW, UPW, and EPW with other solid waste. In conclusion, FW, UPW, and EPW, specially can be potentially energetic biomass and valorized together in the form of a mixture