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On a non-autonomous reaction-convection diffusion model to study the bacteria distribution in a river

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International Journal of Biomathematics 2017年第6期10卷 25-49页

作者： Imene Meriem Mostefaoui Ali Moussaoui laboratoire de mathematiques Image et Applications Universite de La Rochelle Pdle Sciences et Technologies Avenue Michel Crepeau 17000 La Rochelle France laboratoire D'analyse Non Lineaire et mathematiques appliquees Universite de Tlemcen Tlemcen Algeria laboratoire D'analyse Non Lineaire et mathematiques appliquees departement de Mathematique Faculte des Sciences Universite de Tlemcen Tlemcen Algeria

In this paper, we propose a non-autonomous convection-reaction diffusion system （CDI） with a nonlinear reaction source function. This model refers to the quantification and the distribution of antibiotic resistant bacteria （ARB） in a river. The main contributions of this paper are：（i） the determination of the limit set of the system by applying the semigroups theory, it is shown that it is reduced to the solutions of the associated elliptic system （CDI）e, （ii） sufficient conditions for the existence of a positive solution of （CDI）e based on the Leray-Schauder＇s degree theory. Numerical simulations which support our theoretical analysis are also given.

关键词： Reaction-diffusion systems steady states problems degree theory semi-groups.

Multivariate Approach to Characterizing Soil Quality of Gabonese’s Ferralitic Soils

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Open Journal of Soil Science 2024年第4期14卷 237-268页

作者： Neil-Yohan Musadji Rolf Gaël Mabicka Obame Michel Mbina Mounguengui Jean Aubin Ondo Lydie-Stella Koutika Eric Ravire Claude Geffroy laboratoire de Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement Des Sciences Fondamentales De L&#8217Ing&#233nieur Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Institut de Chimie des Milieux et Maté riaux De Poitiers (IC2MP) Universit&#233 De Poitiers Poitiers France laboratoire de Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement De Phytotechnologie Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Dé partement De G&#233ologie Facult&#233 Des Sciences Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon laboratoire Pluridisciplinaire des Sciences Ecole Normale Sup&#233rieure Libreville Gabon Centre de Recherche Sur La Productivité et La Durabilit&#233 Des Plantations Industrielles Pointe Noire Republic of Congo Sucaf Gabon Somdiaa Franceville Gabon

Assessing soil quality is essential for crop management and soil temporal changes. The present study aims to evaluate soil quality in the Ferralitic soils context countrywide. This assessment was done using multivariate soil quality indice (SQI) models, such as additive quality index (AQI), weighted quality indexes (WQIadd and WQIcom) and Nemoro quality index (NQI), applied to two approaches of indicator selection: total data set (TDS) and minimum data set (MDS). Physical and chemical soil indicators were extracted from the ORSTOM’s reports resulting from a sampling campaign in different provinces of Gabon. The TDS approach shows soil quality status according to eleven soil indicators extracted from the analysis of 1,059 samples from arable soil layer (0 - 30 cm depth). The results indicated that 87% of all provinces presented a very low soil quality (Q5) whatever the model. Among soil indicators, exchangeable K+ and Mg2+, bulk density and C/N ratio were retained in MDS, using principal component analysis (PCA). In the MDS approach, 50 to 63% of provinces had low soil quality grades with AQI, WQIadd and NQI, whereas the total was observed with WQIcom. Only 25% of provinces had medium soil quality grades with AQI and NQI models, while 12.5% (NQI) and 25% (AQI) presented high quality grades. Robust statistical analyses confirmed the accuracy and validation (0.80 r P ≤ 0.016) of AQI, WQIadd and NQI into the TDS and MDS approaches. The same sensitivity index value (1.53) was obtained with AQI and WQIadd. However, WQIadd was chosen as the best SQI model, according to its high linear regression value (R2 = 0.82) between TDS and MDS. This study has important implications in decision-making on monitoring, evaluation and sustainable management of Gabonese soils in a pedoclimatic context unfavorable to plant growth.

关键词： Gabon Ferralitic Soil Soil Indicators Standard Score Function Soil Quality Indices Sustainable Soil Soil Management

Hexavalent Chromium Cr (VI) Removal from Water by Mango Kernel Powder

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Journal of Materials Science and Chemical Engineering 2024年第1期12卷 84-103页

作者： Amadou Sarr Gning Cheikh Gaye Antoine Blaise Kama Pape Abdoulaye Diaw Diène Diégane Thiare Modou Fall laboratoire de Chimie Physique Organique et d’analyses Environnementales (LCPOAE) Université Cheikh Anta Diop Dakar Sénégal Equipe Chimie des Matériaux Inorganique et Organique (ECMIO) Université Alioune Diop Bambey Sénégal Equipe des Matériaux Electrochimie et Photochimie Analytiques (EMEPA) Université Alioune Diop Bambey Sénégal laboratoire de Photochimie et d’analyse (LPA) Université Cheikh Anta Diop Dakar Sénégal

Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate surface properties and morphology of the adsorbent.

关键词： Adsorption Chromium Mango Kernel Powder Spectroscopy Analysis Water Treatment

Evaluation of the Inhibitory Gel Aloe vera against Corrosion of Reinforcement Concrete in NaCl Medium

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Materials Sciences and Applications 2024年第5期15卷 101-112页

作者： Malang Bodian Dame Keinde Kinda Hannawi Modou Fall Aveline Darquennes Prince William Agbodjan laboratoire de Chimie Physique Organique et d’ Analyse Environnementales (LCPOAE) D&#233partement de Chimie Universit&#233 Cheikh Anta Diop de Dakar Dakar Senegal laboratoire de Gé nie Civil et G&#233nie M&#233canique (LGCGM) INSA Rennes Universit&#233 de Rennes Rennes France Civil Engineering Materials Laboratory (LMGC) Ecole Sup&#233rieure Polytechnique de Dakar (Senegal) Universit&#233 Cheikh Anta Diop Dakar S&#233n&#233gal

Most reinforced concrete structures in seaside locations suffer from corrosion damage to the reinforcement, limiting their durability and necessitating costly repairs. To improve their performance and durability, we have investigated in this paper Aloe vera extracts as a green corrosion inhibitor for reinforcing steel in NaCl environments. Using electrochemical methods (zero-intensity chronopotentiometry, Tafel lines and electrochemical impedance spectroscopy), this experimental work investigated the effect of these Aloe vera (AV) extracts on corrosion inhibition of concrete reinforcing bar (HA, diameter 12mm) immersed in a 0.5M NaCl solution. The results show that Aloe vera extracts have an average corrosion-inhibiting efficacy of around 86% at an optimum concentration of 20%.

关键词： Reinforced Concrete Green Inhibitor Corrosion Reinforcement Electrochemical Methods

Evaluation of the Level of Pollution by Heavy Metals of Market Garden Soils along the Chari River in Ndjamena: Case of the 9th and 7th Districts

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Agricultural Sciences 2024年第8期15卷 939-961页

作者： Kotva Wana Mackaye Hassane Taisso Likius Andossa Béral djétenbé laboratoire Gosciences Dpartement des Sciences de la Terre Facult des Sciences Universit de NDjamena NDjamena Chad laboratoire Gosciences Dpartement des Sciences de la Terre Facult des Sciences Universit de Mongo Mongo Chad laboratoire Sol et Environnement (LASEN) Dpartement des Sciences de la Terre Facult des Sciences Universit de Ngaoundr Ngaoundr Cameroun

The main aim of this study was to characterize the metal content of soils used for market gardening along the Chari river: the 7th and 9th districts of Ndjaména. To achieve this, two sites were selected: Gassi and Walia, and two control sites (Gassi and Walia). A total of fifty (50) soil samples were taken (24 from the Gassi site, 24 from the Walia site and 2 as control soils) and then analyzed to determine a number of physico-chemical parameters (pH, OM and electrical conductivity) and heavy metal concentrations in the various soils. The TME content (As, Cd, Cu, Cr, Ni, Pb, Hg and Zn) of the soils was determined by plasma-coupled Atomic Emission Spectrometry. In order to assess the level of contamination in Gassi and Walia soils, the geoaccumulation index (GeoIndex), contamination factor and degree of contamination were calculated. Results for physico-chemical parameters revealed that pH ranged from acidic (4.6) to moderately neutral (6.5), electrical conductivity was higher in cultivated soils (mean 292.14 μs/cm) than in control soils (mean 149.33 μs/cm), and soils were rich in organic matter. Overall, heavy metal concentrations in cultivated soils were higher than in control soils. The pollution estimate shows that soils in the area have no moderate contamination. The increase in TME concentrations in cultivated soils is thought to be due to the input of agricultural inputs to the soil. However, these levels are below the Average shale reference and Canadian guidelines for agricultural soil quality. Principal component analysis shows that metals are positively and significantly correlated with each other, and negatively and moderately significantly correlated with each other.

关键词： Contamination Agricultural Soils City of N’djaména etM Gassi Walia

Electrochemical Study of the Corrosion Inhibitory Capacity of Calcined Attapulgite in Reinforced Concrete Medium

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Advances in Materials Physics and Chemistry 2024年第5期14卷 76-94页

作者： Malang Bodian Kinda Hannawi Dame Keinde Modou Fall Aveline Darquennes Prince William Agbodjan Faculté des Sciences et Techniques D&#233partement de Chimie Universit&#233 Cheikh Anta Diop de Dakar (S&#233n&#233gal) Laboratoire de Chimie Physique Organique et d&#8217Analyse Environnementales (LCPOAE) Dakar Senegal Dé partement de G&#233nie Civil Universit&#233 de Rennes INSA Rennes Laboratoire de G&#233nie Civil et G&#233nie M&#233canique (LGCGM) Rennes France Dé partement de G&#233nie Civil Universit&#233 Cheikh Anta Diop Ecole Sup&#233rieure Polytechnique de Dakar (S&#233n&#233gal) Laboratoire de Mat&#233riaux de G&#233nie Civil (LMGC) Dakar Senegal

The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main factors of corrosion of reinforced concrete structures. This study aims to valorize a clay inhibitor against reinforcement corrosion in reinforced concrete. This clay (Attapulgite) was incorporated into reinforced concretes at different percentages of substitution of calcined attapulgite (0%, 5% and 10%) to cement in the formulation. The corrosion inhibitory power of attapulgite is evaluated in reinforced concretes subjected to the action of chloride ions at different intervals in the NaCl solution (1 day, 21 days and 45 days) by electrochemical methods (zero current chronopotentiometry, polarization curves and electrochemical impedance spectroscopy). This study showed that in the presence of chloride ions, the composition based on 10% attapulgite has an appreciable inhibitory effect with an average inhibitory efficiency of 82%.

关键词： Attapulgite Electrochemical Methods Inhibitor Reinforced Concrete

On a certain non-split cubic surface

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Science China Mathematics 2019年第12期62卷 2435-2446页

作者： Regis de la Breteche Kevin destagnol Jianya Liu Jie Wu Yongqiang Zhao Institut de mathematiques de Jussieu Universite Paris-DiderotParis 75205France IST Austria Klosterneuburg 3400Austria School of Mathematics Shandong UniversityJinan 250100China laboratoire d'analyse et de mathematiques appliquees Univer site Paris-Est CreteilCNRSUMR 8050Creteil 94010France School of Science Westlake UniversityHangzhou 310024China

This paper establishes an asymptotic formula with a power-saving error term for the number of rational points of bounded height on the singular cubic surface of P3 Qgiven by the following equation x0（x12+ x22）-x33= ... 详细信息

关键词： Manin-Peyre conjecture rational points singular cubic surface non-split toric surface descent on torsors asymptotic formula

Mg(OH)_2 Nanorods Synthesized by A Facile Hydrothermal Method in the Presence of CTAB

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Nano-Micro Letters 2011年第3期3卷 153-159页

作者： Hassouna Dhaouadi Hedia Chaabane Fathi Touati "laboratoire des Matriaux Utiles" Institut National de Recherche et d’analyse Physico-chimique Ple technologique de Sidi-Thabet "laboratoire de Microbiologie" Institut National de Recherche et d’analyse Physico-chimique Ple technologique de Sidi-Thabet

Magnesium hydroxide(Mg(OH)_2) nanorods were synthesized by a simple and facile hydrothermal method in the presence of cetyltetramethylammonium bromide(CTAB) as a surfactant. Nanorods of magnesium oxide Mg O were also induced by thermal decomposition of Mg(OH)_2 nanorods at 700. By using disk diffusion technique, the Mg(OH)_2 nanorods were found to exhibit higher antibacterial efficiency against several tested bacterial strains.

关键词： Nanorods Morphology Hydrothermal synthesis

Mother-to-Child Transmission of Human Papillomavirus in Burkina Faso

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American Journal of Molecular Biology 2024年第1期14卷 13-24页

作者： Koudpoko Madeleine Kabre djénéba Ouermi Théodora Mahoukèdè Zohoncon Fatié Porzé Wilfried Traore Prosper Bado Abdoul Karim Ouattara Ouamini Pulchérie de Prisca Gnoumou Rogomenoma Alice Ouedraogo Albert Théophane Yonli Punya Akouélé Kuassi-Kpede Charlemagne Marie Ragnag-Néwendé Ouedraogo Jacques Simpore laboratoire de Biologie Moléculaire et de Génétique (LABIOGENE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Centre de Recherche Biomoléculaire Pietro Annigoni (CERBA) Ouagadougou Burkina Faso Faculté des Sciences de la Santé Université Saint Thomas d’Aquin Ouagadougou Burkina Faso laboratoire de Biologie Moléculaire H&#244pital Saint Camille de Ouagadougou (HOSCO) Ouagadougou Burkina Faso University Joseph Ki-Zerbo UFR/SDS Ouagadougou Burkina Faso

Introduction: Human papillomavirus (HPV) infection is the most widespread sexually transmitted infection in the world. Today, there is growing evidence that HPV can be transmitted early in life, and one potential route is mother-to-child transmission. Data on this route of HPV transmission are scarce in Africa and particularly in Burkina Faso, where no data on the subject are yet available. The aim of our study was to estimate the rate of mother-to-child transmission of HPV infection and to identify circulating genotypes. Methodology: Cervico-uterine samples were collected from 100 full-term pregnant women and, buccal samples were obtained from their newborns at Hopital Saint Camille de Ouagadougou (HOSCO) by the specialist physician. HPV DNA amplification and genotyping were performed by PCR followed by hybridization using the HPV Direct Flow Chips kit, detecting 36 genotypes including 18 high-risk and 18 low-risk. Results: The prevalence of HPV in newborns was 8% (8/100). Six (6) HPV-positive neonates had HPV-positive mothers, while 2 HPV-positive neonates had HPV-negative mothers. The vertical transmission rate was 26.09% (6/23). Mother-newborn genotypes were concordant. However, the genotype profile of the newborns was more restricted than that of the mothers. Conclusion: HPV DNA was found in 8% of newborns in our study. The genotype profile of the mother-newborn pair was concordant. Asymptomatic HPV infection in a pregnant woman could constitute a risk factor for vertical transmission.

关键词： Mother-to-Child Transmission Human Papillomavirus PCR Genotypes Burkina Faso