Publications récentes
ARTICLE
Identification and phylogenetic analysis of carbapenemase genes from clinical strains of Klebsiella pneumoniae
Boukaré Kaboré, Ganamé A Ouédraogo, Henri S Ouédraogo, Hama Cissé, Oumarou Zongo, Koudbi J Zongo, Boukaré Zeba, Idrissa Sanou, Aly SavadogoIntroduction: Klebsiella pneumoniae is an encapsulated Gram-negative bacterium that is responsible for numerous infections in healthcare facilities worldwide and is frequently isolated. The World Health Organization has listed K. pneumoniaeas as a critical antibiotic resistant bacterial pathogen for which new antibiotics are urgently needed. This study aimed to use molecular tools to identify and examine antibiotic resistance in clinical strains of K. pneumoniae.
Methodology: A total of 15 unduplicated K. pneumoniae strains isolated from patient samples with multidrug-resistant (MDR) profiles were subjected to polymerase chain reaction (PCR) to amplify the most common carbapenem resistance genes. (GTG)5 PCR and phylogenetic analysis were performed to identify the genetic relationship between the strains.
Results: All strains yielded a (GTG)5-PCR profile, and this allowed us to group these strains into 8 groups according to the size and number of characteristic bands. Phylogenetic analysis was done using the free software UPGMA and a single bacterial clone with a correlation coefficient of over 97% was identified. New Delhi metallo-beta-lactamase NDM-like (blaNDM) carbapenem resistance genes were detected in three strains of K. pneumoniae, which represented a resistance rate of 20%. However, carbapenemases type A [Klebsiella pneumoniae carbapenemase (KPC) and imipenem-hydrolysing beta-lactamase (IMI), type D [oxacillinase-48 (OXA-48)], and other metallo-β-lactamase [Verona integron-encoded metallo-beta-lactamase (VIM), and enzyme active on imipenem (IMP)] were not detected.
Conclusions: We identified and grouped the blaNDM resistance genes of Klebsiella pneumonia strains.
ARTICLE
COPULA OF BERNSTEIN AND DEGREE OF DISCORDANCE
Vini Yves Bernadin LOYARA, Fabrice OUOBA et Rémi Guillaume BAGREThe analytical expression for the degree of multivariate discordance in probability has a high level of mathematical elegance. This is why we were interested in the degree of discrepancy. In addition, while working on this expression, an application to the Bernstein copula appeared more accessible. We therefore modeled the expression for the Bernstein copula and the degree of discordance.
ARTICLE
Optimal Sizing of Output Energy of PV Power Plants under Extreme Climate Conditions: Case of Sudanian Sahel
Boubacar SORO, Amadou DIALLO, Serge Dimitri Y. B. BAZYOMO, Adama OUEDRAOGO, Seyni SALACK; Dieudonné Joseph BATHIEBO, Sié KAMThe present work analyzes the energy production of three 50kWp photovoltaic (PV) power plants which are placed in three climate zones. The Sudano-Sahelian and Sudanian climates have lower average temperatures than the Sahelian environment. The Sudanian climate, next the Sudano-Sahelian zone, and finally the Sahelian region, have the best performance for PV power plants. The performance of silicon PV cells may suffer due to temperature. The Sahelian climatic zone experiences its highest levels of PV output between April and October due to longer sunshine hours and a reduction in sand dust. In the Sudano-Sahelian region, PV output is at its peak between May and October. The best PV generation in the Sudanian environment occurs between June and November. The theoretical forecasting for the various climate zones is consistent with the PV mini-grid real energy output in various situations. The humidity, cloud cover, and rainfall in all climatic zones will make August the worst month for PV energy generation. Due to the type of load compared to the Sudanian climate where the PV power plant is situated in a university, the usage of batteries is crucial in the Sudano-Sahelian climate.
ARTICLE
Greenhouse gas emission from prescribed fires is influenced by vegetation types in West African Savannas
Valaire Séraphin Ouehoudja Yaro, Loyapin Bondé , Pawend‑taoré Christian Bougma, Issoufou Sedgo, Reginald Tang Guuroh, Amanuel Woldeselassie Gebremichael, Tiga Neya, Anja Linstädter, Oumarou OuédraogoGreenhouse gas (GHG) emissions from prescribed fires are poorly investigated, resulting in a high uncertainty in GHG budgets. Using, a carbon mass balance approach and experimental prescribed fires in 80 plots, this study assessed carbon emissions and established emission factors (EFs) for carbon dioxides (CO2), carbon monoxide (CO), and methane (CH4) across climate zones and vegetation types. In grass and shrub savannas, fires could burn intensely due to the lower moisture content and continuous spatial distribution of biomass fuel, causing greater carbon emissions with 1.61 ± 0.13 t C ha−1 and 1.01 ± 0.13 t C ha−1, respectively. Despite their low carbon emissions, tree savannas
(1658.17 ± 11.13 g kg−1) and woodlands (1629.94 ± 12.23 g kg−1) have the highest EFs, which can be attribute to the high carbon content of biomass fuel in these vegetation types. Vegetation types and their interaction with climate zones have a substantial impact on carbon emissions and carbon species EFs, and should therefore be considered in assessing GHG emissions from fires. The findings from this study provide a useful basis for improving the national measurement, reporting, and verification of GHG emissions and for improving the measurement of the global balance of GHG emissions from fires.
ARTICLE
Assurance-vie, développement financier et croissance économique en Afrique subsaharienne : une nouvelle approche
Relwendé Sawadogo, Benjamin Natama, et Daouda DraboLa littérature sur l’impact de l’assurance-vie sur la performance économique dans les pays en développement reste peu concluante. Dans cet article, nous examinons la possibilité que les pays suivent des régimes de croissance différents, et testons l’hypothèse selon laquelle l’assurance-vie affecte différemment la croissance économique dépend du régime de croissance auquel appartient une économie. Ainsi, en utilisant un modèle de mélange fini sur 34 pays d’Afrique subsaharienne au cours de la période 1999-2022, nous identifions deux régimes de croissance. L’assurance-vie a un effet positif et significatif dans le premier, tandis que dans le second, elle n’a pas d’effet significatif. De plus, nous utilisons le modèle à effet aléatoire de Mundlak (1978) pour capter le fait que le développement financier augmente la possibilité qu’un pays appartienne à un régime dans lequel l’assurance-vie influence positivement la croissance économique. Ces résultats suggèrent que le secteur financier peut être un canal permettant d’accentuer l’effet de l’assurance-vie sur la croissance.
ARTICLE
Pharmaceutical approaches for enhancing solubility and oral bioavailability of poorly soluble drugs
Isaïe Nyamba , Charles B Sombié, Moussa Yabré , Hermine Zimé-Diawara , Josias Yaméogo , Salfo Ouedraogo , Anna Lechanteur, Rasmané Semdé , Brigitte EvrardHigh solubility in water and physiological fluids is an indispensable requirement for the pharmacological efficacy of an active pharmaceutical ingredient. Indeed, it is well established that pharmaceutical substances exhibiting limited solubility in water are inclined towards diminished and inconsistent absorption following oral administration, consequently resulting in variability in therapeutic outcomes. The current advancements in combinatorial chemistry and pharmaceutical design have facilitated the creation of drug candidates characterized by increased lipophilicity, elevated molecular size, and reduced aqueous solubility. Undoubtedly, the issue of poorly water-soluble medications has been progressively escalating over recent years. Indeed, 40% of the top 200 oral medications marketed in the United States, 33% of drugs listed in the US pharmacopoeia, 75% of compounds under development and 90% of new chemical entities are insufficiently water-soluble compounds. In order to address this obstacle, formulation scientists employ a variety of approaches, encompassing both physical and chemical methods such as prodrug synthesis, salt formation, solid dispersions formation, hydrotropic substances utilization, solubilizing agents incorporation, cosolvent addition, polymorphism exploration, cocrystal creation, cyclodextrins complexation, lipid formulations, particle size reduction and nanoformulation techniques. Despite the utilization of these diverse approaches, the primary reason for the failure in new drug development persists as the poor aqueous solubility of pharmaceutical compounds. This paper, therefore, delves into the foundational principles that underpin the implementation of various formulation strategies, along with a discussion on the respective advantages and drawbacks associated with each approach. Additionally, a discourse is provided regarding methodological frameworks for making informed decisions on selecting an appropriate formulation strategy to effectively tackle the key challenges posed during the development of a poorly water-soluble drug candidate.
ARTICLE
Exploration of entomotherapeutic potential of bees’ products and termite nests from Burkina Faso
Mamadou Ouango, Hama Cissé, Rahim Romba, Samuel Fogné Drabo, Rasmané Semdé, Aly Savadogo, Olivier GnankinéIn Burkina Faso, products and nests of insect are used for therapeutic purposes in traditional medicine. However, this
use by local populations is marginal and empirical. The objective of this study was to evaluate the antimicrobial activity of extracts of bees’ products and termite nests. Thus, the collected termite nests were finely ground. Hydroethanolic extraction of bioactive molecules with potential antibacterial activity was performed according to standard methods. The agar diffusion method was used to test the antibacterial activity of hydroethanolic extracts of honey bee, bee wax, propolis, and termite nests against 22 pathogenic strains by inhibition diameter. Imipenem and nystatin were used as a positive control for bacterial and fungal strains respectively. The extraction yields varied from 7.33 to 35.39% depending on the content of soluble matter. All extracts of bees’ products and termite nests tested showed inhibitory activities. The inhibition diameters varied depending on the extract and strain tested. The largest diameter of inhibition (26 ± 0.0 mm) was obtained using the nest extract of Macrotermes bellicosus against Salmonella Typhimurium ATCC14028. The lowest diameter of inhibition was 7 ± 0.0 mm obtained with honey extract against Pseudomonas aeruginosa ATCC27853. Index multi-resistance of the extracts tested were between 0.2 and 0.6. Interestingly, the inhibition diameters and activity coefficient of certain products and nest extracts of insects were sometimes greater than those of imipenem/nystatin against the strains tested. This study revealed the antimicrobial potential of termite nest extracts and hive products against pathogens.
ARTICLE
CONSTRUCTION OF A CLASS OF COPULAS WITH HORIZONTAL OR VERTICAL SECTION OF A HOMOGRAPHIC FUNCTION
Herman Tiemtoré, Bagre Remi Guillaume, Loyara Vini Yves BernadinThe construction of multivariate distributions with arbitrary margins has been a problem of interest to statisticians for many years, but nowadays, by virtue of Sklar’s theorem, this problem can be reduced to the construction of a copula. However, there is no general method for constructing a copula. In order to provide a partial solution to this problem, we present in this article, a construction of a new class of ratio-type copulas called a class of copulas with horizontal or vertical section of a homographic function. Indeed, the horizontal section of the copulas of this class can be considered as a homographic function of variable u whose coefficients are functions of v (formula (8)) and the vertical section can be considered as a homographic function of variable v whose coefficients are functions of u (formula (9)). This class can be also considered as a generalization of Ali-Mikhail-Haq family of copulas. We present some examples of copulas in this class.
ARTICLE
On exponential stability of mild solution of a stochastic integrodifferential equation in a complex Hilbert space
Wahabo BAGUIAN; Victorien KONANE; Claude YAMEOGOIn this work, we consider a system of stochastic integrodifferential
equations in a complex Hilbert space. We first establish the existence
and uniqueness of mild solutions for equation (1) under non-Lipschitz
conditions. Then we show under certain assumptions that the found
mild solution is exponentially stable on average of order n. Note that
the same equation was studied in [10] where the authors found the
solution in a real Hilbert space. We now provide a generalization of
this result in a complex Hilbert space. We obtain existence and
uniqueness results by using the Lipschitz global and growth conditions
ARTICLE
Dynamics of a SVEIR Epidemic Model with a Delay in Diagnosis in a Changing Environment
Hamadoum Dicko, Ali Traoré, Désiré OuedraogoSVEIR epidemic model with a delay in diagnosis is studied in a constant and variable environment. The mathematical analysis shows that the dynamics of the model in the constant environment are completely determined by the magnitude of the delay-induced reproduction number Rα. We established that if Rα<1, the disease-free equilibrium is globally asymptotically stable, and when Rα>1 the endemic equilibrium is globally asymptotically stable. In the variable environment, the model undergoes a transcritical bifurcation for Rα=1 leading to changes in the stability of the equilibrium points. The analytical effect of the delays in epidemic diagnosis is investigated. A minimum diagnosisrateαminhas been determined to face or control the disease effectively. Finally, numerical illustrations were presented tosupport the theoretical results