On Traffic Patterns of HTTP Applications

International audienc

Adaptive Parametric Routing Based on Dynamic Metrics for Wireless Sensor Networks

International audienceDesigning a QoS-aware, yet energy-saving routing protocol for WSNs is a notoriously hard problem. However, the outstanding interest for this technology, and the growing number of envisioned applications, motivate the need to introduce the notion of Quality of Service (QoS) in these networks. This paper introduces EDEAR (Energy and Delay Efficient Adaptive Routing), an adaptive routing algorithm based on route exploration and reinforcement learning. We evaluate EDEAR with simulations, under various network mobility conditions. Our results show that EDEAR outperforms any other routing protocol, delivering packets with the shortest delay, while reducing energy consumption. As a result, EDEAR's features allow to increase the network lifetime by 9-18

Étude biologique de deux espèces d'Aleurodes Bemisia tabaci Gennadius et Trialeurodes vaporariorum West (Homoptera, Aleurodidae) sur tomate dans la région du Souss Massa

L’étude biologique de deux espèces d’aleurodes inféodées à la tomate (Bemisia. tabaci et Trialeurodes vaporariorum) a été réalisée, d’une part, dans la station expérimentale d’Ait Amira et, d’autre part, dans trois exploitations dans région du Souss Massa. L’analyse de la composition démographique de leurs populations sur feuilles et le suivi de leurs adultes sur plaques jaunes ont permis de montrer que B. tabaci est le ravageur nuisible et le vecteur le mieux représenté sur tomate dans la région. Il atteint des proportions variant de 52 à 92%. L’espèce semble évoluer en 3 à 4 générations chevauchantes lorsqu’on se base sur le suivi hebdomadaire de ses pupes et la chronologie d’émergence de ses adultes

Valorisation du marc du café : extraction de l’huile et évaluation de son activité antioxydante

The spent coffee grounds are considered as a solid waste generated by coffee consumers. The present work aims to enhance this co-product rich in high value-added molecules. Indeed, the spent coffee grounds are extracted by two methods, Soxhlet and decoction. The solvent used in both processes to extract the lipid fraction was n-hexane. Both extractions, Soxhlet and decoction, were conducted under the same operating conditions. The Soxhlet extract 11% (dray mass) of oil after three hours of extraction and decoction extract 8% (dry mass) of oil after only 30 minutes. Preliminary characterization of these extracts, by the Folin Ciocalteu protocol, provided 28 mg GAE/g of total phenolic compounds for the Soxhlet extract, and 30 mg GAE/g for the decoction extract. The antioxidant activity of different extracts was assessed by two methods, the test of free radical scavenging, using the diphenyl picrylhydrazyl (DPPH•), and Ferric Reducing Antioxidant Power (FRAP) test. The extracts showed significant antioxidant potential. 70% of inhibition of DPPH° free radicals were observed for 30 min decoction extract and a higher iron reducing power for Soxhlet and decoction extracts.Le marc du café est considéré comme un déchet solide généré par les consommateurs de café moulu. Le présent travail a pour but de valoriser ce coproduit riche en molécules de haute valeur ajoutée. En effet, le marc du café est soumis à une extraction par deux procédés, le Soxhlet et la décoction. Le solvant utilisé dans les deux procédés pour extraire la fraction lipidique est le n-hexane. Les deux extractions, par Soxhlet et par décoction, ont été conduites dans les mêmes conditions opératoires. Le procédé Soxhlet abouti à 11% (base sèche) de l’huile totale de marc de café après trois heures d’extraction et environ 8% (base sèche) d’huile après seulement 30 minutes d’extraction par décoction. La caractérisation préliminaire de ces extraits a fourni, selon la méthode de Folin Ciocalteu, une teneur en composés phénoliques totaux de 28 mg GAE/g pour l’extrait de trois heures par Soxhlet, et 30 mg GAE/g pour l’extrait d’une heure par décoction. L’activité antioxydante des différents extraits a été évaluée par deux méthodes. Le test de piégeage du radical libre DiPhényl Picryl Hydrazyl (DPPH•) et le teste de réduction des ions de fer Ferric Reducing Antioxidant Power (FRAP). Les extraits ont manifesté un important potentiel antioxydant. Un pourcentage d’inhibition de 70% du radical DPPH remarqué pour l’extrait de 30 minutes par décoction et un pouvoir réducteur de fer plus élevé pour l’extrait de 4 heures par Soxhlet et celui de 3 heures par décoction

Characterization of immunoglobulin G antibodies to Plasmodium falciparum sporozoite surface antigen MB2 in malaria exposed individuals

<p>Abstract</p> <p>Background</p> <p>MB2 protein is a sporozoite surface antigen on the human malaria parasite <it>Plasmodium falciparum</it>. MB2 was identified by screening a <it>P. falciparum </it>sporozoite cDNA expression library using immune sera from a protected donor immunized via the bites of <it>P. falciparum</it>-infected irradiated mosquitoes. It is not known whether natural exposure to <it>P. falciparum </it>also induces the anti-MB2 response and if this response differs from that in protected individuals immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes. The anti-MB2 antibody response may be part of a robust protective response against the sporozoite.</p> <p>Methods</p> <p>Fragments of polypeptide regions of MB2 were constructed as recombinant fusions sandwiched between glutathione S-transferase and a hexa histidine tag for bacterial expression. The hexa histidine tag affinity purified proteins were used to immunize rabbits and the polyclonal sera evaluated in an <it>in vitro </it>inhibition of sporozoite invasion assay. The proteins were also used in immunoblots with sera from a limited number of donors immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes and plasma and serum obtained from naturally exposed individuals in Kenya.</p> <p>Results</p> <p>Rabbit polyclonal antibodies targeting the non-repeat region of the basic domain of MB2 inhibited sporozoites entry into HepG2-A16 cells <it>in vitro</it>. Analysis of serum from five human volunteers that were immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes that developed immunity and were completely protected against subsequent challenge with non-irradiated parasite also had detectable levels of antibody against MB2 basic domain. In contrast, in three volunteers not protected, anti-MB2 antibodies were below the level of detection. Sera from protected volunteers preferentially recognized a non-repeat region of the basic domain of MB2, whereas plasma from naturally-infected individuals also had antibodies that recognize regions of MB2 that contain a repeat motif in immunoblots. Sequence analysis of eleven field isolates and four laboratory strains showed that these antigenic regions of the basic domain of the <it>MB2 </it>gene are highly conserved in parasites obtained from different parts of the world. Moreover, anti-MB2 antibodies also were detected in the plasma of 83% of the individuals living in a malaria endemic area of Kenya (n = 41).</p> <p>Conclusion</p> <p>A preliminary analysis of the human humoral response against MB2 indicates that it may be an additional highly conserved target for immune intervention at the pre-erythrocytic stage of <it>P. falciparum </it>life cycle.</p

Antioxidant and cytotoxic activities of sulfated polysaccharides from five different edible seaweeds

In recent times, there has been a growing interest in the exploration of antioxidants and global trend toward the usage of seaweeds in the food industries. The low molecular weight up to 14 kDa sulfated polysaccharides of seaweeds (Portieria hornemannii, Spyridia hypnoides, Asparagopsis taxiformis, Centroceras clavulatum and Padina pavonica) were evaluated for in vitro antioxidant activities and cytotoxic assay using HeLa cell line and also characterized by FTIR. The high yield (7.74% alga dry wt.) of sulfated polysaccharide was observed in P. hornemannii followed by S. hypnoides (0.69%), C. clavulaum (0.55%) and A. taxiformis (0.17%). In the brown seaweed P. pavonica, the sulfated polysaccharide yield was 2.07%. High amount of sulfate was recorded in the polysaccharide of A. taxiformis followed by C. clavulaum, P. pavonica, S. hypnoides and P. hornemannii as indicative for bioactivity. The FTIR spectroscopic analysis supports the sulfated polysaccharides of S. hypnoides, C. clavulatum and A. taxiformis are similar to agar polymer whereas the spectral characteristics of P. hornemannii have similarities to carrageenan. The higher DPPH activity and reducing power were recorded in the polysaccharide of brown seaweed P. pavonica than the red seaweeds as follows: DPPH activities: S. hypnoides > A. taxiformis > C. clavulatum > P. hornimanii; Reducing power: A. taxiformis > P. hornimanii > S. hypnoides > C. clavulatum. The polysaccharide fractions contain up to 14 kDa from red seaweeds P. hornemannii and S. hypnoides followed by brown seaweed P. pavonica exhibit cytotoxic activity in HeLa cancer cell line (and are similar to structural properties of carrageenan extracted from P. hornemannii). The low molecular weight agar like polymer of S. hypnoides and alginate like brown seaweed P. pavonica showing better in vitro antioxidant activities that are capable of exhibiting cytotoxicity against HeLa cell line can be taken up further in-depth investigation for nutraceutical study.University of Algarve: DL 57/2016info:eu-repo/semantics/publishedVersio

Delineation of Stage Specific Expression of Plasmodium falciparum EBA-175 by Biologically Functional Region II Monoclonal Antibodies

EBA-175 binds its receptor sialic acids on glycophorin A when invading erythrocytes. The receptor-binding region (RII) contains two cysteine-rich domains with similar cysteine motifs (F1 and F2). Functional relationships between F1 and F2 domains and characterization of EBA-175 were studied using specific monoclonal antibodies (mAbs) against these domains..The role of the F1 and F2 domains in erythrocyte invasion and binding was elucidated with mAbs. These mAbs interfere with native EBA-175 binding to erythrocyte in a synergistic fashion. The stage specific expression of EBA-175 showed that the primary focus of activity was the merozoite stage. A recombinant RII protein vaccine consisting of both F1 and F2 domains that could induce synergistic activity should be optimal for induction of antibody responses that interfere with merozoite invasion of erythrocytes

Why Functional Pre-Erythrocytic and Bloodstage Malaria Vaccines Fail: A Meta-Analysis of Fully Protective Immunizations and Novel Immunological Model

Background: Clinically protective malaria vaccines consistently fail to protect adults and children in endemic settings, and at best only partially protect infants. Methodology/Principal Findings: We identify and evaluate 1916 immunization studies between 1965-February 2010, and exclude partially or nonprotective results to find 177 completely protective immunization experiments. Detailed reexamination reveals an unexpectedly mundane basis for selective vaccine failure: live malaria parasites in the skin inhibit vaccine function. We next show published molecular and cellular data support a testable, novel model where parasite-host interactions in the skin induce malaria-specific regulatory T cells, and subvert early antigen-specific immunity to parasite-specific immunotolerance. This ensures infection and tolerance to reinfection. Exposure to Plasmodium-infected mosquito bites therefore systematically triggers immunosuppression of endemic vaccine-elicited responses. The extensive vaccine trial data solidly substantiate this model experimentally. Conclusions/Significance: We conclude skinstage-initiated immunosuppression, unassociated with bloodstage parasites, systematically blocks vaccine function in the field. Our model exposes novel molecular and procedural strategies to significantly and quickly increase protective efficacy in both pipeline and currently ineffective malaria vaccines, and forces fundamental reassessment of central precepts determining vaccine development. This has major implications fo