Colistin is one of the last-line therapies against multidrug-resistant Gram-negative pathogens, especially carbapenemase-producing isolates, making resistance to this compound a major global public-health crisis. Until recently, colistin resistance in Gram-negative bacteria was known to arise only by chromosomal mutations. However, a plasmid-mediated colistin resistance mechanism was described in late 2015. This mechanism is encoded by different mobile colistin resistance (mcr) genes that encode phosphoethanolamine (pEtN) transferases. These enzymes catalyse the addition of a pEtN moiety to lipid A in the bacterial outer membrane leading to colistin resistance. MCR-producing Gram-negative bacteria have been largely disseminated worldwide. However, their environmental dissemination has been underestimated. Indeed, water environments act as a connecting medium between different environments, allowing them to play a crucial role in the spread of antibiotic resistance between the natural environment and humans and other animals. For a better understanding of the role of such environments as reservoirs and/or dissemination routes of mcr genes, this review discusses primarily the various water habitats contributing to the spread of antibiotic resistance. Thereafter, we provide an overview of existing knowledge regarding the global epidemiology of mcr genes in water environments. This review confirms the global distribution of mcr genes in several water environments, including wastewater from different origins, surface water and tap water, making these environments reservoirs and dissemination routes of concern for this resistance mechanism.

Ephedra altissima Desf. est une plante médicinale de la famille des Ephedraceae, largement utilisée en médecine traditionnelle pour le traitement des maladies respiratoires et le diabète. L’objectif de la présente étude est l’évaluation des activités biologiques in vitro et la caractérisation phytochimique des extraits (éther de pétrole, acétate d’éthyle et n-butanol) obtenus à partir de la plante Ephedra altissima. Des dosages colorimétriques ont été effectués pour révéler la présence de différentes classes de métabolites secondaires. La détermination des teneurs en polyphénols, flavonoïdes et tanins condensés a été réalisée par des dosages spectrophotométriques. L’activité antioxydante a été évaluée par huit méthodes différentes, l’activité anti-artéritiques a été réalisée par la méthode d’inhibition de la dénaturation du sérum d’albumine bovin, les activités inhibitrices de l’α-amylase et de la lipase pancréatique in vitro ont été estimées par des méthodes colorimétriques en utilisant de l'amidon et du p-nitrophényl butyrate en tant que substrats. Les conditions physiologiques de la digestion humaine ont été simulées par le modèle de la digestion gastro-intestinale (DGI) in vitro. L’activité antibactérienne a été déterminée par la méthode de diffusion sur disques en milieu gélosé contre sept souches bacteriennes. L’analyse et la quantification des composés phénoliques ont été effectuées par LC-DAD-ESI/MS. L’investigation phytochimique de l’extrait n-butanolique a été réalisée par l’utilisation en alternance de diverses méthodes chromatographiques (VLC, CC, CCE et CCM). Les structures des deux composés isolés A et B ont été identifiées par analyse spectroscopique ESI-MS, l’UV et la RMN dans ses multiples techniques, RMN 1H, RMN 13C, et RMN 2D (COSY, HSQC, HMBC et TOCSY). A l’issue de ces travaux, nous retiendrons la richesse de cette plante en métabolites secondaires. En effet, l’extrait AcOEt présente la teneur la plus élevée en polyphénols (125,62 μg EAG mg-1), et le n-BuOH possède la teneur la plus élevée en flavonoïdes (19,18 μg EQ mg-1). Tous les extraits ont des activités antioxydantes dans divers systèmes et l'extrait aqueux a montré une bonne activité antioxydante par la méthode potentiométrique. L’extrait AcOEt exhibe la plus forte activité anti-artéritique, activités inhibitrices de de l’α-amylase et de la lipase pancréatique avec des valeurs de CI50 (126,4 ± 2,36, 8,07 ± 0,15 et 289,1 ± 0,53 μg/ml) respectivement. Tous les extraits testés exercent une activité antibactérienne dose dépendante contre au moins trois souches avec des CMI allant de (3,12 à 50 μg/ml). L’analyse par LC-DAD-ESI/MS a permis de détecter la présence de dix-neuf composés différents, huit sont des acides phénoliques simples et des dérivés d'acide phénolique, et onze sont des flavonoïdes liés à des groupes glycosyles. L’investigation phytochimique réalisée sur l’extrait n-batanolique conduit à l’isolement et identification structurale de deux flavonoides glycosylés nommés : Isorhamnétine 3-O- α-L-rhamnopyranosyl (1’’’-6’’)- β-D-galactopyranoside et Kaempférol 3-O- α-L-rhamnopyranosyl (1’’’-6’’)- β-D-glucopyranoside.

The Biocheck.UGent scoring system was developed to measure and quantify the level of biosecurity in animal husbandry. This tool is composed of all the relevant elements of biosecurity in poultry farms (broilers and laying hens) and is subdivided into external and internal biosecurity. The peculiarity of this scoring system is that it takes into account the relative importance of the different aspects of biosecurity, resulting in a risk-weighted score. The biosecurity scores obtained are provided immediately after completing the questionnaire and the scores for each sub-category can be compared to global averages to allow the poultry farmer to compare the results obtained and correct any anomalies that are on their farm. In Algeria, preliminary results from a survey in poultry houses of 30.000 laying hens show a wide range of biosecurity levels on that farm, with internal biosecurity scores ranging from 6 to 72% and external biosecurity scores ranging from 28 to 92% in the subgroups. The overall scores were 50% and 54%, respectively. These early results show that despite the well-known importance of biosecurity, there is a lack of implementation of many biosecurity measures.

The Mio-Plio-Quaternary groundwater of Mchira-Teleghma suffers from an increasing rate of salinity especially in the northwestern part. To identify the reason for the water’s salinity and its aptitude for irrigation, physico-chemical analyses of 20 water samples, which were based on the different physical and chemical parameters (electric conductivity EC, pH, Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃⁻, Cl⁻, SO₄²⁻, NO₃⁻ and Sr²⁺), were carried out during the period of October 2015. This study showed disquieting anomalies of electric conductivity that reached the value of 4376.14 µS cm⁻¹. The statistical analyses, the multivariate statistics: the principal component analysis, Q-mode cluster analyses, Sr²⁺/Ca²⁺ ratio and water type showed that the hydrochemistry of Mchira-Teleghma groundwater is controlled by the dissolution of carbonate rocks and the leaching of evaporite processes, which proved that these anomalies of the MPQ groundwater’s salinity of Mchira-Teleghma are mainly determined by the leaching of Triassic gypsum formations process. This hydrogeochemical process generates an unsuitable quality of water based on Wilcox’s and Water Quality Index’s methods, whereas Richard’s method classifies all water samples to C3S1 and C4S1 classes as they are recommended to be used with salt-tolerant species in well-drained and leached soils.

Purpose: To determine the anti-inflammatory and anti-ulcer properties of the aerial parts of Centaurea tougourensis Boiss. & Reut.

 

Methods: The effects of n-butanol (n-BuOH) extract of the aerial part of Centaurea tougourensis on carrageenan-induced paw edema and ethanol-induced gastric mucosal damage were determined at 2 doses (200 and 400 mg/kg, po) in a mouse model. For each test, the animals were randomly divided into negative and positive control groups, as well as extract-treated groups. The mice were observed for any sign of inflammation for a period of 24h.

 

Results: Reduction of paw edema by C. tougourensis extract was highly significant (p < 0.001) at a dose of 400 mg/kg 24 h after carrageenan injection, with 55.26 % inhibition, followed very closely by 53.15 % inhibition at the dose of 200 mg/kg; indomethacin group showed an inhibition of 60 %. Histological examination supported the inhibition results. A significant reduction in inflammation by the extract at a dose of 400 mg/kg was also observed. No sign of ulcer was observed with C. tougourensis at the two doses (200 and 400 mg/kg). The total polyphenol content of the n-BuOH extract was 85.44 цg gallic acid equivalent/mg of extract. Tannins were the most abundant fraction (51.87 цg tannic acid equivalent/mg of extract), followed by flavonoids (25.55 цg quercetin equivalent/mg of extract).

 

Conclusion: The results indicate that C. tougourensis may have potential beneficial effects in the treatment of diseases associated with inflammation and pain, besides its protective effect on the gastrointestinal tract.

In this article, we consider a coupled system of two nonlinear hyperbolic equations, where the exponents in the damping and source terms are variables. First, we prove a theorem of existence and uniqueness of weak solution, by using the Faedo Galerkin approximations and the Banach fixed point theorem. Then, using the energy method, we show that certain solutions with positive initial energy blow up in finite time. We also give some numerical applications to illustrate our theoretical results.

This paper provides a new proof of the existence and uniqueness of the solution for a nonlinear boundary value problem

which describes the study of two-phase Stefan problems on the semi-infinite line [0, ∞). This result considerably extends the analysis of a recent work. A highly accurate analytic approximate solution of this problem is also provided via the Adomian decomposition method.

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000oC with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400oC.

In the present study, both experimental and numerical were conducted on a free surface flow over an obstacle. Numerical simulations were performed using the Renormalization Group (RNG-k-ɛ) based Reynolds-Averaged Navier–Stokes (RANS) turbulence model coupled with the Volume OF Fluid (VOF) method in FLUENT Software to investigate the effect of the channel slope on the flow pattern upstream, above and downstream the obstacle. Respectively, 5%, 7%, 8%, 10%, 20% and 50% channel slopes were considered. Numerical simulation has showed a good agreement compared against experimental results. Effect of the slope on the flow is observed particularly upstream of the obstacle where the flow takes the vertical direction after hitting the upstream wall. The more the slope becomes steeper, the higher the level of the water is. Recirculation zones in the case of a horizontal channel are elongated downstream the weir, whereas in the case of a sloped channel, they are localized just at the foot of the downstream wall.

The present study focuses on the investigation of the behaviour of a reduced model of a reinforced soil massif by a sand column tested in the laboratory. These tests involved the installation of sand columns in clay specimens (kaolin) by different methods. The specimens thus obtained are subjected to the same oedometric loading program. The first part of this work aims to study the effect of the intensity of the compaction stress of the sand columns on the surrounding soil and the effect on the behaviour of the soil-column massif. The sand columns were installed with the soil replacement method and with compacting of the columns (WR_WC). Three different compaction stresses were used to install the columns. In the second part, a sand column 20 mm in diameter was installed by two methods: one with replacement of the soil (WR) and without compaction and the other with displacement of the soil (WD). A comparison between the two methods has been established. By determining the equivalent characteristics for the soil-column massif, this study made it possible to characterize the effect of the installation method of the columns on the settlements, the void ratioe of kaolin, the equivalent void ratio e_eq of the massif soil-column and on the compressibility parameters of the massif (equivalent compression index C_ceq and swelling index C_seq), by comparing the results obtained with those of the unreinforced soils that constitute the reference case. The results obtained showed that the techniques used for the installation of columns have significant effects on the behaviour of reinforced massifs.

In this paper, the exact solutions to the AB nonlinear system are investigated. This system is reduced via two different transformations to a sine-Gordon equation and a quasilinear equation for a new dependent variable ϕ. Solutions to a sineGordon equation and a quasilinear equation are found. Hence, the original system can well be solved for such ϕ. Also, a similar approach is proposed to solve analytically an eventual extension system for the case of variable coefficients.

In recent years the development of health science to improve people’s lives and reduce the death rate from cardiovascular disease, researchers have invested in the solution of stents to treat cardiovascular disease. Usually a permanent implant (metal stent) is used to treat a temporary disease, effective on elastic recoil and negative remodeling, but promoting intimate proliferation. This is combated by an active stent, which nevertheless induces chronic inflammation and delayed healing (because of active drugs), with the risk of late thrombosis. The idea of resolution leads to the study of the behavior of temporary stent biodegradable and bioresorbable, once the healing process is completed. The purpose of this study is to reduce the disadvantages of metal stents, to do this; a biodegradable material (polylactic acid) is used. The fatigue behavior of a stent after its placement using geometric parameters selected from clinical cases (diastole and systole). A finite element numerical study in the field of biomaterial fatigue is proposed in order to investigate and understand the biodegradable behavior of the stent. The results of the numerical study show the predicted lifetime of the biodegradable fragrance.

The integration of a fault tolerance mechanism in critical real-time embedded systems is an important and required property to ensure the continuity of delivering the expected service even in the presence of faults to avoid catastrophic consequences that can be generated in the event of failure of these systems. In this research paper we present a solution to tolerate permanent faults of one processor in heterogeneous distributed real-time embedded systems by using software redundancy solutions based on active and passive replication of dependent tasks in the point-to-point connection. The methodology proposed consists to generate a distribution/scheduling of tasks on hardware architecture and also to tolerate permanent faults of a single processor by executing simultaneously two replicas of a task, the first which ends its execution blocks the second is running. this principle saves very considerable time in distribution/scheduling length with and without errors.

Contrairement à l’abstention-surveillance, la surveillance active est une modalité de prise en charge curative. Elle vise à retarder le traitement d’une tumeur peu agressive jusqu’au moment où elle le deviendra tout en restant dans la fenêtre de curabilité de la maladie. À travers une lecture de littératures, nous allons essayer de maitre la lumière sur la place et les modalités de la surveillance active, dans les groupes favorables des cancers de la prostate et de répondre aux questions suivantes : Pourquoi la surveillance active ? Pour qui ? Comment l’instauré ? et quand doit-on l’arrêter ? La majorité des essais, cliniques publiés s’accordent à dire, que la surveillance active est une attitude parfaitement adaptée aux patients du groupe favorable d’AMICO, voire même une partie du groupe intermédiaire bas risque. Les résultats en matière de survie globale et d’évènement métastatiques, sont similaires à ceux des patients traités d’emblée par chirurgie et ou radiothérapie, avec en plus moins de toxicité. La surveillance est basée essentiellement sur le dosage périodique du PSA, rebiopsie selon des protocoles propres à chaque équipe. La décision du passage aux traitements invasifs, sera conditionnée par la progression du score Gleason, selon des algorithmes dont certains, sont déjà validés à l’international. La surveillance active, doit faire partie intégrante des décisions de prise en charge des adénocarcinomes prostatiques localisés favorables. Cette attitude nous permet, d’éviter de surtraiter un grand nombre, de petites lésions non évolutives, tout en ayant la possibilité et les moyens, de rattraper les lésions qui progressent.

Image classification has been one of the most widely topic in artificial intelligence, deep models need larger datasets and powerful hardware to improve the highperformance classification. ImageNet Challenge was started in 2010 to classify 100,000 test images into 1000 different classes. Tiny ImageNet challenge is similar to ImageNet challenge, where images are taken from the standard ImageNet and resized to be 64x64. In this paper a fine-tuned Xception to classify images into the 200 classes is presented using the standard Tiny ImageNet dataset, the down-sampling (64x64) of images and the low similarity inter-class makes feature extraction and classification difficult and more challenging. We used a transfer learning algorithm to fine-tune the Xception architecture using the Extreme version of the Inception module to achieve a high validation accuracy of 65.14%.

The novel coronavirus outbreak (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents the actual greatest global public health crisis. The lack of efficacious drugs and vaccines against this viral infection created a challenge for scientific researchers in order to find effective solutions. One of the promising therapeutic approaches is the search for bioactive molecules with few side effects that display antiviral properties in natural sources like medicinal plants and vegetables. Several computational and experimental studies indicated that flavonoids especially flavonols and their derivatives constitute effective viral enzyme inhibitors and possess interesting antiviral activities. In this context, the present study reviews the efficacy of many dietary flavonols as potential antiviral drugs targeting the SARS-CoV-2 enzymes and proteins including Chymotrypsin-Like Protease (3CL^pro), Papain Like protease (PL^pro), Spike protein (S protein) and RNA-dependent RNA polymerase (RdRp), and also their ability to interact with the angiotensin-converting enzyme II (ACE2) receptor. The relationship between flavonol structures and their SARS-CoV-2 antiviral effects were discussed. On the other hand, the immunomodulatory, the anti-inflammatory and the antiviral effects of secondary metabolites from this class of flavonoids were reported. Also, their bioavailability limitations and toxicity were predicted.

Floods become major concerns in most gobe regions due to socio-economic and environmental consequences caused by these phenomena in recent decades. Most Algerian cities are exposed to flood risks and suffered from its consequences. The purpose of this paper is the spatialization of flood hazard in the city of Chemora (Algeria) by hydraulic modelling in a GIS environment whose objective is prevention, which requires a set of hydrological and hydraulic informations in order to achieve a comprehensive and effective management.