Strojno učenje i neuronske mreže u modeliranju zadržavanja polarnih farmaceutski aktivnih tvari nanofiltracijom i reverznom osmozom

The retention of polar pharmaceutical active compounds (PPhACs) by nanofiltration and reverse osmosis (NF/RO) membranes is of paramount importance in membrane separation processes. The retention of 21 PPhACs was correlated using artificial intelligence techniques: multi-layer perceptron (MLP), feedforward neural network with radial basis function (RBF), and support vector machine (SVM). A database of 541 retention values has been collected from the literature. The results showed a high predictive capacity of the MLP model for the retention of PPhACs by NF/RO with a very high correlation coefficient (R = 0.9714) and a very low root mean squared error (RMSE = 3.9139 %) for the entire data set. The comparison between the three models showed the superiority of the MLP model. The sensitivity analysis emphasised that the retention of PPhACs is governed by three interactions arranged in descending order: polarity interactions (hydrophobicity/hydrophilicity), electrostatic repulsion, and steric hindrance. This research suggests that the PPhACs retention on the NF/RO membrane strongly depends on the topological polar surface area.Zadržavanje polarnih farmaceutski aktivnih tvari (PPhAC) tijekom nanofiltracije i reverzne osmoze (NF/RO) od iznimne je važnosti u membranskim separacijskim procesima. Membransko zadržavanje 21 PPhAC-a korelirano je sa svojstvima PPhAC-a, karakteristikama membrane i uvjetima provedbe procesa filtracije. Pri tome su primijenjene tehnike umjetne inteligencije: višeslojni perceptron (MLP), neuronska mreža s radijalnom baznom funkcijom (RBF) i metoda potpornih vektora (SVM). Iz literature je prikupljena 541 vrijednost zadržavanja. Rezultati su pokazali visok kapacitet predviđanja MLP modela za cijeli skup podataka, s vrlo visokom vrijednošću koeficijenta korelacije (R = 0,9714) i vrlo niskom vrijednošću korijena srednje kvadratne pogreške (RMSE = 3,9139 %). Usporedba s preostala dva modela (RBF i SVM) pokazala je superiornost MLP modela. Analiza osjetljivosti ukazala je na to da zadržavanjem PPhAC-a upravljaju tri interakcije i to (padajućim redoslijedom): polarne interakcije (hidrofobnost/hidrofilnost), elektrostatsko odbijanje i steričke smetnje. Provedenoo istraživanje sugerira da zadržavanje PPhACs na NF/RO membrani snažno ovisi o topologiji polarne površine

Itinéraires spécifiques vers le professorat des écoles à La Réunion

La réussite au concours de professorat des écoles est généralement associée à certaines caractéristiques individuelles des candidats, sur le plan scolaire ou socio-démographique. Dans le contexte particulier d’un département français ultra-marin, La Réunion, ces variables exercent une influence parfois différente. Le parcours de formation post-bac et les expériences professionnelles de certains candidats témoignent de la construction d’un itinéraire explicitement ou implicitement contextualisé. Dans la mesure où cette influence contextuelle est généralement perçue comme un handicap difficile à surmonter, une interrogation peut être légitimement suscitée quant à l’application des principes d’égalité et d’équité sur l’ensemble du territoire national.The achievement in primary school teaching examination appears to be mainly linked with the individual background of the applicants. In the specific context of Reunion Island, which is one of the four French overseas regional areas, the social and economic background could have quite a different impact. We notice that for some applicants the specific context operates more or less significantly on the professional experience and the higher education curriculum. If we take into consideration the perception of this specific context as a problematic handicap, the accuracy of equality and equity principles could be questioned from a national point of view

Modeli umjetne neuronske mreže za predviđanje gustoće i kinematičke viskoznosti različitih sustava biogoriva i njihovih mješavina s dizelskim gorivom. Usporedna analiza

In the present article, two models based on the artificial neural network methodology (ANN) have been optimised to predict the density (ρ) and kinematic viscosity (μ) of different systems of biofuels and their blends with diesel fuel. An experimental database of 1025 points, including 34 systems (15 pure systems, 14 binary systems, and 5 ternary systems) was used for the development of these models. These models use six inputs, which are temperature (T) in the range of −10 – 200 °C, volume fractions (X1, X2, X3) in the range of 0–1, and to distinguish these systems, we used kinematic viscosity at 20 °C in the range of 0.67–74.19 mm2 s–1 and density at 20 °C in the range of 0.7560–0.9188 g cm–3. The best results were obtained with the architecture of {6-26-2: 6 neurons in the input layer – 26 neurons in the hidden layer – 2 neurons in the output layer}. Results of comparison between experimental and simulated values in terms of the correlation coefficients were: R2 = 0.9965 for density, and R2 = 0.9938 for kinematic viscosity. A 238 new database experimental of 4 systems (2 pure systems, 1 binary system, and 1 ternary system) was used to check the accuracy of the two ANN models previously developed. Results of prediction performances in terms of the correlation coefficients were: R2 = 0.9980 for density, and R2 = 0.9653 for kinematic viscosity. Comparison of validation results with those of the other studies shows that the neural network models gave far better results. This work is licensed under a Creative Commons Attribution 4.0 International License.U ovom članku dva modela zasnovana na metodologiji umjetne neuronske mreže (ANN) optimizirana su za predviđanje gustoće (ρ) i kinematičke viskoznosti (μ) različitih sustava biogoriva i njihovih mješavina s dizelskim gorivom. Za razvoj tih modela upotrijebljena je eksperimentalna baza podataka od 1025 točaka, uključujući 34 sustava (15 čistih sustava, 14 binarnih sustava i 5 ternarnih sustava). Ti modeli koriste šest ulaza: temperatura (T) u rasponu od −10 do 200 °C, volumni udjeli (X1, X2, X3) u rasponu 0 – 1, a za razlikovanje tih sustava korištena je kinematička viskoznost pri 20 °C u rasponu 0,67 – 74,19 mm2 s–1 i gustoća pri 20 °C u rasponu 0,7560 – 0,9188 g cm–3. Najbolji rezultati dobiveni su arhitekturom {6-26-2: 6 neurona u ulaznom sloju – 26 neurona u skrivenom sloju – 2 neurona u izlaznom sloju}. Rezultati usporedbe eksperimentalnih i simuliranih vrijednosti u smislu korelacijskih koeficijenata bili su: R2 = 0,9965 za gustoću i R2 = 0,9938 za kinematičku viskoznost. Za provjeru točnosti dva prethodno razvijena modela ANN upotrijebljeno je 238 novih eksperimentalnih baza podataka s 4 sustava (2 čista sustava, 1 binarni sustav i 1 ternarni sustav). Rezultati performansi predviđanja s obzirom na korelacijske koeficijente bili su: R2 = 0,9980 za gustoću i R2 = 0,9653 za kinematičku viskoznost. Usporedba rezultata validacije s rezultatima drugih studija pokazuje da su modeli neuronske mreže dali znatno bolje rezultate. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Antibacterial activity of various honey types of Algeria against Staphylococcus aureus and Streptococcus pyogenes

AbstractObjectiveTo assess the in vitro antibacterial activity of honey from different geographical location on Gram negative organismes.MethodsDifferent concentrations (Undiluted honey, 10 %, 30%, 50% and 70% wt/vol) of honey were studied in vitro using Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes), briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MICs were determined by both visual inspection and spectrophotometric assay at 620 nm. These honey samples were compared with standard antibiotics like ampicillin, penicillin G, amoxicillin, gentamycin, tobramycin, erythromycin and chloramphenicol was determined by the disc diffusion method.ResultsThe diameter of zone of the inhibition (ZDI) of honey has various concentrations tested for the isolates ranged 0–46 mm for S. aureus, 0–44 mm for S. pyogenes. While the MIC (%) ranged 12%-95%, 25%-73% respectively.ConclusionsAlgeria honey, in-vitro, possess antibacterial activity

A Quantitative Structure Activity Relationship for acute oral toxicity of pesticides on rats: Validation, Domain of Application and Prediction

International audienceQuantitative Structure Activity Relationship (QSAR) models are expected to play an important role in the risk assessment of chemicals on humans and the environment. In this study, we developed a validated QSAR model to predict acute oral toxicity of 329 pesticides to rats because a few QSAR models have been devoted to predict the Lethal Dose 50 (LD50) of pesticides on rats. This QSAR model is based on 17 molecular descriptors, and is robust, externally predictive and characterized by a good applicability domain. The best results were obtained with a 17/9/1 Artificial Neural Network model trained with the Quasi Newton back propagation (BFGS) algorithm. The prediction accuracy for the external validation set was estimated by the Q2ext and the Root Mean Square error (RMS) which are equal to 0.948 and 0.201, respectively. 98.6% of external validation set is correctly predicted and the present model proved to be superior to models previously published. Accordingly, the model developed in this study provides excellent predictions and can be used to predict the acute oral toxicity of pesticides, particularly for those that have not been tested as well as new pesticides

Estimation of Properties of Liquid-Vapor Mixture of Some Refrigerants at High Pressure for Solar-Photovoltaic Refrigeration

Abstract. In this work, a hybrid method based on neural network and particle swarm optimization is applied to literature data to develop and validate a model that can predict with precision vapor-liquid equilibrium data for the binary systems (hexafluoroethane (R116(1)), 1,1,1,2-tetrafluoroethane (R134a) and R1234ze) . ANN was used for modelling the non-linear process. The PSO was used for two purposes: replacing the standard back propagation in training the ANN and optimizing the process. The training and validation strategy has been focused on the use of a validation agreement vector, determined from linear regression analysis of the predicted versus experimental outputs, as an indication of the predictive ability of the neural network model. Statistical analysis of the predictability of the optimized neural network model shows excellent agreement with experimental data (coefficient of correlation equal to 0.998). Furthermore, the comparison in terms of average relative deviation (AARD%) between, the predicted results for the whole temperature and pressure range shows that the ANN-PSO model can predict far better the mixture properties than cubic equations of state

Les garrots de prélèvement, un drame chez le nourrisson: à propos de 3 cas

Le délai pour la levée d'un garrot sur un membre est limité, tout retard, surtout après la 3ème heure expose à un risque d'amputation de celui-ci. Notre objectif a été de rapporter trois cas de gangrène ischémique de membre par oubli d'un garrot après un prélèvement sanguin, afin d'interpeler le personnel soignant sur ses dangers. Il s'est agi de trois nourrissons dont deux de 3 mois et un de 5 mois, reçus aux urgences viscérales du CHU-Yalgado Ouédraogo pour tuméfaction du membre thoracique gauche. Dans leurs antécédents, on a noté une pose de garrot pour prélèvement de sang qui a été oublié pendant 24 heures dans deux cas et 48 heures dans un cas. L'examen avait retrouvé un oedème diffus associé à un sphacèle du membre supérieur remontant jusqu'au 1/3 moyen du bras; une abolition des pouls ulnaire et radial ainsi que de la sensibilité de la main dans 2 cas. Dans un cas les signes étaient atténués. Le diagnostic de gangrène ischémique de membre a été retenu dans tous les cas. La biologie réalisée était normale. En urgence, il a été réalisé une amputation trans-humérale dans 2 cas et un débridement associé à une amputation de quatre doigts dans un cas. L'évolution a été simple dans tous les cas. La gangrène sèche iatrogène de membre par garrot en milieu hospitalier ne devrait pas se concevoir. Cela passe par la rigueur dans l'administration des soins et une surveillance régulière et attentive des patients.Pan African Medical Journal 2016; 2

Complications du diverticule de Meckel (DM) chez l’adulte: à propos de 11 cas au CHU-Yalgado Ouédraogo au Burkina Faso

Le diverticule de Meckel (DM) est la persistance partielle du canal omphalomésentérique. Ses complications sont rares. Le diagnostic est le plus souvent per opératoire. L’objectif a été de décrire les complications du diverticule de Meckel chez l'adulte dans le service de chirurgie générale et digestive du CHU Yalgado Ouédraogo. Il s'est agi d'une étude transversale descriptive sur 10 ans (janvier 2004-décembre 2013) portant sur les dossiers des patients âgés de plus de 15 ans ayant présenté un DM compliqué. Durant la période d'étude, 11 cas ont été colligés. L'incidence annuelle a été de 11 cas. Nous avons noté une prédominance masculine avec un sex-ratio de 4,5. L'âge moyen des patients était de 29,8 ans. Le diagnostic préopératoire a été dans huit cas une occlusion intestinale aiguë, une appendicite aiguë dans deux cas, une péritonite aiguë généralisée dans un cas. Il a été diagnostiqué en peropératoire une occlusion intestinale dans neuf cas; une diverticulite dans un cas et un cas de perforation du DM. Tous les DM avaient été réséqués dont huit résections segmentaires iléales emportant le DM et trois résections cunéiformes. Tous les DM étaient situés à moins d'un mètre de la jonction iléo-caecale. L'histologie réalisée dans deux cas avait conclu à une diverticulite. Les suites opératoires ont été simples dans neuf cas, compliquées dans deux cas dont une éventration et un décès. Les complications du diverticule de Meckel sont rares. Le diagnostic préopératoire est difficile. Le traitement est essentiellement chirurgical.Pan African Medical Journal 2015; 2