On the Link Between Strongly Connected Iteration Graphs and Chaotic Boolean Discrete-Time Dynamical Systems

Chaotic functions are characterized by sensitivity to initial conditions, transitivity, and regularity. Providing new functions with such properties is a real challenge. This work shows that one can associate with any Boolean network a continuous function, whose discrete-time iterations are chaotic if and only if the iteration graph of the Boolean network is strongly connected. Then, sufficient conditions for this strong connectivity are expressed on the interaction graph of this network, leading to a constructive method of chaotic function computation. The whole approach is evaluated in the chaos-based pseudo-random number generation context

Action antibactérienne de l’extrait éthanolique 70% de Clerodendrum splendens (G. Don) (Verbenacae) sur des souches bactériennes isolées de selles chez des enfants diarrhéiques

L’apparition des bactéries résistantes aux antibiotiques et leur diffusion dans la population humaine constituent un réel problème de santé publique. C’est ainsi que le monde scientifique a découvert de nombreux traitements qui ont permis de réduire l’indice des maladies causées par ces germes. Malgré ce succès, on ne cesse d’enregistrer la résistance des bactéries aux antibactériens. Ainsi, le développement de nouveaux agents antibactériens s’avère indispensable pour lutter contre ces fléaux. C’est dans ce but que notre objectif vise à tester l’extrait éthanolique 70% de Clerodendrum splendens (G.don) sur quelques entérobactéries isolées de selles chez des enfants diarrhéiques. La méthode de dilution en milieu liquide gélosé Muller-Hinton® utilisant différentes concentrations d’extrait a permis d’évaluer l’activité antibactérienne de l’extrait. Les résultats obtenus montrent que toutes les souches bactériennes sont sensibles à l’extrait éthanolique 70%. Cet extrait est bactéricide sur Proteus mirabilis et bactériostatique sur Escherichia coli, Salmonella typhi et Shigella sp.Mots clés: Extrait éthanolique 70%, Clerodendrum splendens, Entérobactéries, Diarrhée, Bactériostatique, Bactéricide

A Topological Study of Chaotic Iterations. Application to Hash Functions

International audienceChaotic iterations, a tool formerly used in distributed computing, has recently revealed various interesting properties of disorder leading to its use in the computer science security field. In this paper, a comprehensive study of its topological behavior is proposed. It is stated that, in addition to being chaotic as defined in the Devaney's formulation, this tool possesses the property of topological mixing. Additionally, its level of sensibility, expansivity, and topological entropy are evaluated. All of these properties lead to a complete unpredictable behavior for the chaotic iterations. As it only manipulates binary digits or integers, we show that it is possible to use it to produce truly chaotic computer programs. As an application example, a truly chaotic hash function is proposed in two versions. In the second version, an artificial neural network is used, which can be stated as chaotic according to Devaney

In vitro antifungal activity of the soap formulation of the hexane leaf extract of morinda morindoides (morinda; rubiaceae)

Purpose: The aim of this study was to formulate the hexane extract of the leaves of Morinda morindoides (Baker) Milne-Redh (Rubiaceae) as soap and evaluate its antifungal activity against fungal isolates of human origin. Method: The hexane extract of Morinda morindoides was incorporated as an antifungal agent in soap (SMM) and tested against 4 strains of dermatophytes (Candida albicans, Trichophyton rubrum, Trichophyton mentagrophytes and Aspergillus fumigatus) using basic soap (BS) as control. Agar dilution method at serial concentrations ranging from 125 mg/ml to 3.9 mg/ml was used for the determination of the antimicrobial parameters - MIC (minimum inhibitory concentration) and IC50 (concentration producing 50 % inhibition) for these strains.Result: The growth of all fungal strains tested was inhibited by the Morinda morindoides extract soap (SMM) at MIC of 31.25 mg/ml. On the other hand, basic soap (control) inhibited Candida albicans at MIC of 125 mg/ml and at MIC of 62.50 mg/ml for the other 3 strains tested. Thus, SMM showed stronger antifungal activity against the strains tested than the control (basic soap). Conclusion: The hexane extract of Morinda morindoides leaves incorporated in soap exerted antifungal activity against the fungal strains tested. Thus, this soap formulation may find use in the treatment of dermatomycoses.Keywords: Morinda morindoides; Antifungal activity; Hexane extract; Soap; Dermatophyte

Cholinergic and anticholinesterase activities of total protein extract of Morinda morindoïdes on isolated rabbit duodenum

Traditional herbal medicines such as Morinda morindoïdes are used for treatment of intestinal disorders including constipation in Ivory Coast. The aim of present study was to investigate the effect of total protein of Morinda morindoïdes extract (PT-Mm) on rabbit duodenum contractility and the involved possible mechanism(s). PT-Mm was extracted according to the saturation method of Dawson with ammonium sulfate. The cholinergic effect of the extract was determined by the in vitro organ bath method. The acetylcholinesterase (AChE) extracted from rabbit duodenum and it activity was determined by Ellman’s assay using acetylthiocholine (ASCh) as substrate. PT-Mm concentrations (40, 80, 120 and 200 μg/mL) showed dose-dependent effect a both tonicity and amplitude of the duodenum spontaneous contractions. The effective concentration which induces 50% effect of PT-Mm (EC50) was obtained with 68.57 ± 0.89 μg/mL. The antagonist tests carried out showed a considerable reduction (90%) in the amplitudes of duodenal contractions in the presence of atropine, but with nifedipine, the contractions were completely inhibited. PT-Mm also exerted non-competitive inhibition on AChE (Vmax = 5687 mM/min and KM = 578 μM). These results suggest that PT-Mm could stimulate duodenum smooth muscle contraction because it contains anti-AChE and cholinomimetic substances which, through muscarinic receptors, increase Ca2+ mobilization from extracellular. Therefore, PT-Mm could be used as a laxative, due to its stimulating effects on duodenal contractility.Keywords: Morinda morindoides, acetylcholinesterase, duodenum, contractio

Long term response to steroid therapy in Rasmussen encephalitis

SummaryRasmussen encephalitis (RE) is a severe and progressive focal epilepsy of unknown origin that leads to deterioration of motor and cognitive function. In a previous study, we described positive effect of high doses of steroids during the first year after the onset of RE. The objective of this study was to evaluate this therapy at long term.We reviewed 11 patients (7 girls and 4 boys) with RE of the right hemisphere (7) and the left (4) at a follow-up of 9±2 years. Age at onset of RE ranged from 2 to 14 years.Six patients had no benefit from steroid therapy and underwent hemispherotomy. Five had significant reduction of seizure frequency with disappearance of epilepsia partialis continua, and improved motor function. Of these, two died of unexpected sudden death 5 and 7 years after seizure control. Two others with initial response experienced progressive recurrence of seizures 1 to 4 years after the end of steroid therapy and required hemispherotomy. Finally, only one patient exhibited total cessation of seizures with steroids for 3 years, but seizures progressively recurred although the frequency was moderate.Our data confirm that although steroid treatment can be useful when given early in the course of RE, long term relapse can occur among the good responders requiring delayed hemispheric disconnection

Effet antibactérien de l’extrait aqueux de l’écorce de Terminalia glaucescens Planch ex Benth (Combretaceae) sur la croissance in vitro des entérobactéries productrices de bêta-lactamases à spectre élargi (EBLSE)

Les bacteries productrices de beta-lactamases a spectre elargi sont responsables des echecs therapeutiques a infection bacterienne. Cette etude vise a evaluer les effets antibacteriens de lfextrait aqueux du macere d'fecorce de tige de Terminalia glaucescens Planch ex Benth (Combretaceae) sur huit enterobacteries productrices de beta-lactamases a spectre elargi (EBLSE) et deux souches de reference de Escherichia coliATCC. Les methodes de diffusion et de dilution sur Muller-Hinton ont permis dfevaluer l'factivite antibacterienne de l'fextrait. L'factivite  antibacterienne in vitro de l'fextrait aqueux de l'fecorce de tige de T.glaucescens est plus elevee que celle de la ceftriaxone (30 µg) et de la cefotaxime (30 µg) vis-a-vis des souches bacteriennes. Toutes ces souches sont resistantes aux deux antibiotiques, a l''fexception de celles de E. coli ATCC 25922 et 35218. L'fextrait aqueux de T. glaucescens est actif sur les 10 souches. Les zones d'finhibition a 200 mg/ml sont comprises entre 13±0,6 a 19,3±0,6 mm. Les CMI de l'extrait aqueux varient de 1,56 a 50 mg/ml. L'fextrait est bactericide sur toutes les souches apres 24 et 48 heures d'fincubation. Cette etude a montre que l'extrait de T. glaucescens pourrait etre utilise dans le traitement des maladies infectieuses.Mots cles: Terminalia glaucescens, extrait aqueux, activite antibacterienne

Epileptic Spasms in Congenital Disorders of Glycosylation

Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, characterized by impaired glycosylation. Multisystemic involvement is common and neurological impairment is notably severe and disabling, concerning the central and peripheral nervous system. Epilepsy is frequent, but detailed electroclinical description is rare. We describe, retrospectively, the electroclinical features in five children with CDG and epileptic spasms. Epileptic spasms were observed in patients with ALG1-, ALG6, ALG11-CDG and CDG-Ix, and occurred at an early age, before 6 months in all cases, except one who had spasms that started at 18 months. In this patient, spasms had an unusual aspect; they did not occur in clusters and were immediately preceded by a myoclonus. All but one child also presented rare myoclonias. On EEG, background activity was poorly organized with abundant posterior spike and fast rhythm activity, but without hypsarrhythmia. At the last evaluation (age range: 6-12 years), two patients still presented epileptic spasms and subcortical myoclonias, one showed rare generalized tonic-clonic seizures, and two were seizure-free. CDG disorders can be associated with epileptic spasms showing particular features, such as absence of hypsarrhythmia, posterior EEG anomalies, and an unusual combination of epileptic spasms with myoclonus. These features, associated with pre-existing developmental delay and subcortical myoclonias, may shift toward CDG screening. [Published with video sequence and supplemental EEG plates on www.epilepticdisorders.com].info:eu-repo/semantics/publishedVersio

Analyse phytochimique et évaluation de la toxicité aiguë par voie orale chez des rats de l’extrait total aqueux des feuilles de Abrus precatorius Linn (Fabaceae)

Abrus precatorius est reconnue en médecine traditionnelle pour ses nombreuses vertus thérapeutiques. En Côte d’Ivoire, les feuilles sont utilisées dans une boisson pour le traitement des troubles gynécoobstétriques. Au Nigeria, le décocté des feuilles est utilisé dans le traitement du diabète. Des travaux antérieurs sur la plante ont mis en évidence la présence de l’abrine qui est un composé chimique toxique contenu dans les feuilles et dans les graines. L’intérêt de l’utilisation des feuilles de Abrus precatorius exige qu’une approche de sa toxicité puisse être entreprise en vue d’évaluer son innocuité chez l’homme. La présente étude a consisté évaluer la toxicité aiguë par voie orale de l’extrait total aqueux des feuilles de Abrus precatorius (ETAAP) chez des rats. Une analyse phytochimique basée sur des réactions de coloration et/ou de précipitation a été effectué afin d’identifier les composés chimiques présent dans l’extrait. La Dose Létale 50 (DL50) a été déterminée et les animaux ont été observés durant 14 jours après un gavage unique à des doses de 5 mg/kg, 50 mg/kg, 300 mg/kg, 2000 mg/kg et 5000 mg/kg de poids corporels (pc) contre un témoin. La DL50 obtenue a été supérieure à 5000 mg/kg de pc, aucune mortalité et aucun signe clinique de toxicité n’a été observé chez tous les animaux. Cette étude révèle que l’ETAAP est non toxique par voie orale chez des rats. L’analyse phytochimique a montré une hétérogénéité de groupes chimiques (alcaloïdes, tanins, flavones, coumarines, saponines, stérols, triterpènes et des composés réducteurs) dont la présence dans l’extrait pourrait être responsable des propriétés thérapeutiques attribuées à Abrus precatorius.Mot clés : Abrus precatorius L, médecine traditionnelle, innocuité, DL50

Secure Data Aggregation in Wireless Sensor Networks. Homomorphism versus Watermarking Approach

International audienceWireless sensor networks are now in widespread use to monitor regions, detect events and acquire information. Since the deployed nodes are separated, they need to cooperatively communicate sensed data to the base station. Hence, transmissions are a very energy consuming operation. To reduce the amount of sending data, an aggregation approach can be applied along the path from sensors to the sink. However, usually the carried information contains confidential data. Therefore, an end-to-end secure aggregation approach is required to ensure a healthy data reception. End-to-end encryption schemes that support operations over cypher-text have been proved important for private party sensor network implementations. These schemes offer two main advantages: end-to-end concealment of data and ability to operate on cipher text, then no more decryption is required for aggregation. Unfortunately, nowadays these methods are very complex and not suitable for sensor nodes having limited resources. In this paper, we propose a secure end-to-end encrypted-data aggregation scheme. It is based on elliptic curve cryptography that exploits a smaller key size. Additionally, it allows the use of higher number of operations on cypher-texts and prevents the distinction between two identical texts from their cryptograms. These properties permit to our approach to achieve higher security levels than existing cryptosystems in sensor networks. Our experiments show that our proposed secure aggregation method significantly reduces computation and communication overhead and can be practically implemented in on-the-shelf sensor platforms. By using homomorphic encryption on elliptic curves, we thus have realized an efficient and secure data aggregation in sensor networks. Lastly, to enlarge the aggregation functions that can be used in a secure wireless sensor network, a watermarking-based authentication scheme is finally proposed