PREPARATION OF NICKEL - COBALT SPINEL OXIDES NixCO3-xO4.COMPARISON OF TWO PHYSICAL PROPERTIES STEMMING FROM FOUR DIFFERENT PREPARATION METHODS AND USING CARBON PASTE ELECTRODE

A comparative study of two electro-physical properties (porosity and electrical conductivity) of binary nickel cobalt oxides electrodes with spinels mixed oxides NixCo3-xO4 as active matter, was carried out. Four different routes were used to prepare spinel-type NixCo3-xO4 (0 ≤ x ≤ 2.5) compounds in order to link these properties with the preparation method. The substitution of Ni for Co increases the conductivity and the porosity of the electrode till a certain ratio of nickel. X-ray diffraction patterns showed that the oxides crystallize in a cubic spinel phase. Electrical conductivity as well as porosity depends on the preparation route. KEY WORDS: Nickel cobalt spinel oxides, Porosity, Electrical conductivity, Mixed oxides electrodes, Carbon paste electrode, Pechini sol-gel method Bull. Chem. Soc. Ethiop. 2007, 21(2), 255-262

SYNTHESIS AND CHARACTERIZATION OF Ni0.4Co2.6O4 SPINEL MIXED OXIDES POWDER: STUDY OF ITS SURFACE PROPERTIES BY VOLTAMMETRY, X-RAY, FTIR, UV-VIS-NIR SPECTROSCOPY AND SCANNING ELECTRON MICROSCOPY

Electrochemical studies were carried out on Ni0.4Co2.6O4 powders prepared by sol-gel via propionic acid method using cyclic and steady state voltammetries. The oxide surface was characterized by scanning electron microscopy (SEM), X-ray diffraction, UV-vis-NIR and FTIR spectroscopies. The results showed that the formation of homogeneous oxide with a single spinel phase occurred at 350°C. The surface redox couple NiOOH/Ni(OH)2 is confined on the surface material l. KEY WORDS: Ni0.4Co2.6O4 spinel mixed oxides powder, Sol-gel process, Surface properties Bull. Chem. Soc. Ethiop. 2005, 19(2), 213-220

Quality of hydro-alcoholic products used in Senegal: pilot study

Antisepsis and disinfection have always played an important role in the fight against infectious diseases. The use of these products has been effective in breaking the chain of transmission of microorganisms. Today, with the advent of COVID-19, the main recommendations are, among other things, physical distance and the use of antiseptic products, including hydro-alcoholic products. In Senegal, with poor regulations on the acquisition and distribution of antiseptics and disinfectants, this situation has led to a proliferation of antiseptics and disinfectants on the national market. this work aimed to study the quality of hydroalcoholic products found in the trade. We evaluated ten samples of hydro-alcohol products collected during the month of March 2020. Physical and microbiological controls were performed at the National Drug Control Laboratory. The alcohol content of the samples ranged from 63 to 85% and were consistent with WHO recommendations except for samples E3 and E5. The pH values varied between 4.02 and 6.64 and the densities of the hydro-alcoholic gel samples ranged from 0.84 to 0.92 g/cm3; E2, E4, E5, E6 samples had densities greater than 0.89 g/cm3. The samples of hydro-alcoholic products all conformed to the sterility test and no microbiological contamination was observed. Antimicrobial activities of the hydro-alcoholic samples tested ranged from 58.3 to 100% with two samples showing no activity (E2 and E5). In view of the results of this study, it would be relevant to expand and deepen investigations by a significant increase in the number of samples and by carrying out as complete an analysis as possible

Gouvernance transfrontalière du changement climatique dans les régions semi-arides : cas d'étude du Sénégal

Department for International Development (DFiD

Effect of pre-exposure prophylaxis on risky sexual behaviour of female sex workers in Dakar, Senegal:A randomised controlled trial

Background HIV prevention through pre-exposure prophylaxis (PrEP) may encourage riskier sexual behaviours that undermine the protection afforded by PrEP and generate negative spillovers through sexually transmitted infections (STIs). Tests for such risk compensatory behaviour in high-risk populations, such as female sex workers (FSWs), are lacking. This study aims to assess whether risk compensatory behaviours were observed among FSWs in Senegal after the rollout of PrEP. Methods and findings In a randomised controlled trial with a Zelen design, we stratified FSWs in Dakar (Senegal) by self-reported sexual risk-taking and prior PrEP experience and randomly assigned them to immediate referral for oral PrEP (Treatment) from 7 September 2021 to end January 2022 or delayed PrEP referral (Control). We compared outcomes 3–8 months after the referral of the treatment group and before the referral of the control group. Primary outcomes were self-reported condom use with clients and perceived HIV/STI risks from sex with clients with and without a condom. The analysis is a modified intention-to-treat analysis. We estimated effects of PrEP referral as well as effects of oral PrEP use induced by randomised assignment to active PrEP referral. Out of 500 individuals randomised, 308 (61.6%) were included in the analysis (Treatment: 182/300=60.7%; Control: 126/200=63%). PrEP referral increased the probability of using oral PrEP by 34.5 percentage points (pp) (95% CI [25.4, 43.6]; p&lt;0.001). Estimated effects of PrEP referral and PrEP use on condom use with the last client were positive but not statistically significantly different from zero. PrEP referral was estimated to increase the probability of condom use with all of the last three clients by 11.0 pp (95% CI [0.8, 21.2]; p=0.034). PrEP use was estimated to increase this probability by 25.8 pp (95% CI [5.2, 46.4]; p=0.014). Main limitations were low power, high attrition, self-reported outcomes and a limited follow-up period. Conclusions This study, conducted in one location, did not find evidence that PrEP referral or oral PrEP use increased self-reported risky sex behaviours of FSWs within 3–8 months. The robustness of this finding needs to be tested with larger cohorts followed for longer periods in other settings, and using survey instruments that allow further examination of whether PrEP users are more likely to overreport condom use.</p

Feasibility and safety of integrating mass drug administration for helminth control with seasonal malaria chemoprevention among Senegalese children: a randomized controlled, observer-blind trial

BACKGROUND: The overlap in the epidemiology of malaria and helminths has been identified as a potential area to exploit for the development of an integrated control strategy that may help to achieve elimination of malaria and helminths. A randomized, controlled, observer-blind trial was conducted to assess the feasibility and safety of combining mass drug administration (MDA) for schistosomiasis and soil transmitted helminths (STH) with seasonal malaria chemoprevention (SMC) among children living in Senegal. METHODS: Female and male children aged 1-14 years were randomized 1:1:1, to receive Vitamin A and Zinc on Day 0, followed by SMC drugs (sulfadoxine-pyrimethamine and amodiaquine) on Days 1-3 (control group); or praziquantel and Vitamin A on Day 0, followed by SMC drugs on Days 1-3 (treatment group 1); or albendazole and praziquantel on Day 0, followed by SMC drugs on Days 1-3 (treatment group 2). Safety assessment was performed by collecting adverse events from all children for six subsequent days following administration of the study drugs. Pre- and post-intervention, blood samples were collected for determination of haemoglobin concentration, malaria microscopy, and PCR assays. Stool samples were analyzed using Kato-Katz, Merthiolate-iodine-formalin and PCR methods. Urine filtration, PCR and circulating cathodic antigen tests were also performed. RESULTS: From 9 to 22 June 2022, 627 children aged 1-14 years were randomized into the three groups described above. Mild, transient vomiting was observed in 12.6% (26/206) of children in treatment group 2, in 10.6% (22/207) in group 1, and in 4.2% (9/214) in the control group (p = 0.005). Pre-intervention, the geometric mean value of Plasmodium falciparum parasite density was highest among children who received albendazole, praziquantel with SMC drugs. Post-intervention, the parasite density was highest among children who received SMC drugs only. Children who received praziquantel and SMC drugs had a lower risk of developing severe anaemia than their counterparts who received SMC drugs alone (OR = 0.81, 95% CI 0.13-5.00, p = 0.63). CONCLUSIONS: Integration of MDA for helminths with SMC drugs was safe and feasible among Senegalese children. These findings support further evaluation of the integrated control model. TRIAL REGISTRATION: The study is registered at Clinical Trial.gov NCT05354258

Promotion of cardiovascular health in Africa: the Alliance for Medical Research in Africa (AMedRA) expert panel

This proposed scientific statement is focused on providing new insights regarding challenges and opportunities for cardiovascular health (CVH) promotion in Africa. The statement includes an overview of the current state of CVH in Africa, with a particular interest in the cardiometabolic risk factors and their evaluation through metrics. The statement also explains the main principles of primordial prevention, its relevance in reducing noncommunicable disease and the different strategies that have been effective worldwide. Also, the statement addresses challenges for implementing primordial prevention strategies in Africa, such as socioeconomic, cultural, lifestyle, and environmental factors, and highlights the importance of adapting strategies to the context. Finally, the statement recommends fundamental approaches for promoting CVH with the help of various partnerships and the involvement of communities