Cyclic voltammetry and reduction mechanistic studies of styrylpyrylium perchlorates

The reduction and oxidation potentials of methylated 4-styrylpyrylium and 6-styrylpyrylium perchlorates have been evaluated using cyclic voltammetry, in comparison to their non-methylated derivatives values. The reduction peak of all studied compounds remained chemically irreversible. The presence of the electron-donating methyl group on pyrylium ring leads to a shift of the styrylpyrylium perchlorates reduction potential towards cathodic values. Kinetic studies on platinum electrodes based on the variation of the peak potential at different scan rates and upon substrate concentrations confirm, in another way, the mechanism of electron transfer. KEY WORDS: Styrylpyrylium perchlorates, Cyclic voltammetry, Reduction potential, Kinetic study Bull. Chem. Soc. Ethiop. 2013, 27(1), 117-124.DOI: http://dx.doi.org/10.4314/bcse.v27i1.1

Etude des paramètres opératoires d’électrocoagulation pour le traitement d’un effluent de textile : Exemple du bleu de méthylène

Les effluents industriels issus des activités textiles présentent une grande charge polluante difficilement biodégradable et qui a des impacts non négligeables sur l’environnement et l’Homme. Leur décontamination par les procédés conventionnels biologiques ou physiques est souvent inefficace et nécessite par conséquent le recours à des procédés d’oxydation avancée dont l’électrocoagulation. Dans le présent travail, nous avons étudié l’élimination par électrocoagulation du bleu de méthylène, modèle de colorant synthétique textile, en utilisant des électrodes de fer et d’aluminium. L’étude des paramètres pouvant influencer l’élimination par électrocoagulation du bleu de méthylène tels que le pH, la durée de l’électrolyse, la densité de courant et la nature de l’anode a montré que les meilleurs traitements sont obtenus avec un effluent de pH égal à 7 pendant 4 heures d’électrolyse à une densité de courant de 3,75 A/cm2 en utilisant l’électrode de fer. Dans ces conditions, le pourcentage d’élimination du bleu de méthylène dans les eaux atteint 80,1%. Des électrodes en fer seraient donc plus intéressantes pour l’élimination du bleu de méthylène, comparativement à des électrodes en aluminium.Mots clés : Electrocoagulation, fer, aluminium, effluents industriels, bleu de méthylène.   English Title: Study of operator parameters in electrocoagulation for the treatment of a synthetic textile effluent: example of methylene blueIndustrial effluents from textile activities have a large polluting load that is difficult to biodegrade and which has significant impacts on the environment and on humans. Their decontamination by conventional biological or physical processes is often ineffective and therefore requires the use of advanced oxidation processes including electrocoagulation. In the present work, we investigated the  electrocoagulation removal of methylene blue, a synthetic textile dye model, using iron and aluminum electrodes. The study of the parameters of EC which can influence the elimination of methylene blue in wastewater, such as the pH, the duration of the electrolysis, the  current density and the nature of the anode showed that the best treatment are obtained with a pH effluent equal to 7, for 4 hours of electrolysis with an iron electrode at a current density of 3.75 A / cm2. Under these conditions, the percentage of elimination of methylene blue in water reaches 80.1%. Iron electrodes would therefore be more advantageous for the removal of methylene blue, compared to aluminum electrodes.Keywords: Electrocoagulation, iron, aluminum, industrial effluents, methylene blue

Phytochemical Screening and Antioxidant and Cytotoxic Effects of Acacia macrostachya

Acacia macrostachya is used in Burkina Faso folk medicine for the treatment of inflammation and cancer. The purpose of this study was to evaluate the antioxidant and cytotoxic effects of this plant. The cytotoxic effects of root (dichloromethane B1 and methanol B2) and stem (dichloromethane B3 and methanol B4) bark extracts of A. macrostachya were assessed on chronic K562 and acute U937 myeloid leukemia cancer cells using trypan blue, Hoechst, and MitoTracker Red staining methods. The antioxidant content of extracts was evaluated using DPPH (2,2-diphenyl-1-picryl-hydrazyl) and FRAP (ferric reducing antioxidant power) methods. The root bark extracts B1 and B2 of A. macrostachya demonstrated higher cytotoxicity with IC50 values in a low µg/mL range on both U937 and K562 cells, while the stem bark B4 extract selectively affected U937 cells. Overall, healthy proliferating peripheral blood mononuclear cells (pPBMCs) were not or barely impacted in the range of concentrations cytotoxic to cancer cells. In addition, A. macrostachya exhibited significant antioxidant content with 646.06 and 428.08 µg ET/mg of extract for the B4 and B2 extracts, respectively. Phytochemical screening showed the presence of flavonoids, tannins, alkaloids, and terpenoids/steroids. The results of this study highlight the interest of A. macrostachya extracts for the isolation of anticancer molecules

The role and contribution of civil society and community actors in COVID-19 prevention and control: the case of the COMVID COVID-19 movement in Burkina Faso

Communities should play a crucial role in the fight against public health emergencies but ensuring their effective and sustained engagement remains a challenge in many countries. In this article, we describe the process of mobilising community actors to contribute to the fight against COVID-19 in Burkina Faso. During the early days of the pandemic, the national COVID-19 response plan called for the involvement of community actors, but no strategy had been defined for this purpose. The initiative to involve community actors in the fight against COVID-19 was taken, independently of the government, by 23 civil society organisations gathered through a platform called ‘Health Democracy and Citizen Involvement (DES-ICI)’. In April 2020, this platform launched the movement ‘Communities are committed to Eradicate COVID-19 (COMVID COVID-19)’ which mobilised community-based associations organised into 54 citizen health watch units (CCVS) in Ouagadougou city. These CCVS worked as volunteers, performing door-to-door awareness campaigns. The psychosis created by the pandemic, the proximity of civil society organisations to the communities and the involvement of religious, customary and civil authorities facilitated the expansion of the movement. Given the innovative and promising nature of these initiatives, the movement gained recognition that earned them a seat on the national COVID-19 response plan. This gave them credibility in the eyes of the national and international donors, thus facilitating the mobilisation of resources for the continuity of their activities. However, the decrease in financial resources to offset the community mobilisers gradually reduced the enthusiasm for the movement. In a nutshell, the COMVID COVID-19 movement fostered dialogues and collaboration among civil society, community actors and the Ministry of Health, which plans to engage the CCVS beyond the COVID-19 response, for the implementation of other actions within the national community health policy

Corrélations entre les caractéristiques phénotypiques et détermination d’une formule barymétrique chez le taurin Kouri du Niger

Objectif: Cette étude vise à contribuer à la connaissance des caractéristiques phénotypiques du taurin Kouri du Niger.Méthodologie et résultats: Les caractéristiques phénotypiques du taurin Kouri du Niger ont fait l’objet d’une étude conduite dans la région de Diffa au niveau des sites situés aux alentours de Kinjandi dans la commune de Gueskerou et au Centre Secondaire de Multiplication du Bétail de Sayam. Des mensurations ont été effectuées directement sur des animaux et ont permis d’enregistrer des paramètres quantitatifs. Des paramètres qualitatifs ont été renseignés sur la base de l’observation des animaux. Un total de 475 animaux (423 femelles, 36 mâles entiers et 16 mâles castrés) âgés d’au moins 4 ans a été concerné par l’étude. Les moyennes des paramètres phénotypiques quantitatifs suivants ont été notées : Hauteur au garrot (HG) : 125,65±6,08 cm ; Périmètre thoracique (PT) : 157,95±10 cm ; Hauteur au sacrum (HS) : 133,50±6,10 cm ; Largeur aux ischions (LI) : 14,41±2,75. Des différences significatives ont été observées entre les sexes. Le PT est le paramètre le plus corrélé au poids avec un coefficient de corrélation de 0,843. Trois modèles barymétriques sont proposés et ont permis de noter des coefficients d’ajustement de R12=0,79 ; R22= 0,74 et R32= 0,71. Les paramètres phénotypiques qualitatifs ont fait ressortir un profil rectiligne dominant (85,86%) ; des oreilles à orientation latérale (99,79 %) ; des cornes présentes (97,89%) et fixées (97,41%), un dos rectiligne chez 86,50% des animaux. Aussi la couleur blanche de la robe domine avec 50,84 %. Conclusion et application des résultats: En somme, le taurin Kouri du Niger peut être considéré comme une race assez hétérogène sur le plan phénotypique. Cette variabilité pourrait être favorable à une sélection en vue d’une amélioration génétique de la race.Mots clés: phénotype, formule barymétrique, taurin Kouri, NigerEnglish Title: Correlations between Phenotypic measurements and determination of a Barymetric Formula in Niger Kuri cattle breedEnglish AbstractObjective: The main objective of this study is to contribute to increase knowledge on Niger Kuri phenotypic characteristics.Methodology and Results: Phenotypic characteristics of Niger Kuri cattle breed have been assessed in the region of Diffa, Niger, including sampling sites around Kinjandi in Gueskerou commune, and in the Sayam Cattle Secondary Multiplication Center. Measurements were made directly on animals and allowed to record quantitative parameters. Qualitative parameters were given based on the observation of the animals. A total of 475 individuals (423 females, 36 males and 16 castrated males) with at least 4 years age have been sampled. The means values of phenotypic traits measured were as follow: quantitative phenotypic parameters were measured. Height at withers: 125.65 ± 6.08 cm, Heart girth: 157.95 ± 10 cm, height at hips: 133. 50 ± 6.10 cm, Ischium width: 14.41 ± 2.75. Significant differences were observed between sexes. Heart girth is the most correlated parameter to the weight with a correlation coefficient of 0.843. Three barymetric models were used and showed adjusted coefficients of R12 = 0.79, R22 = 0.74 and R32 = 0.71. The qualitative phenotypic parameters revealed à dominant straight profile (85.86%), lateral oriented ears (99.79%), presence of horns (97.89%) and fixed (97.41%), straight back (86.50%) among the individuals. Besides, the white color pattern is predominant (50.84 %).Conclusion and application of results: Overall, Niger Kuri cattle breed may be considered as heterogeneous breed at phenotypic level. This variability may be favorable for selection strategy for this valuable breed improvement.Keywords: phenotype, barymetric formula, Kuri, Nige