Experimental and theoretical investigations of new Schiff base compound adsorption on aluminium in 1 M HCl

The new Schiff base, 2,2\u27-((1Z,1\u27Z)-(((propane-1,3-diylbis(oxy))bis(2,1-phenyle­ne))bis­(me­tha­­nyl­­ylidene))bis(azanylylidene))diethanol, was investigated as a cor­ro­sion inhibitor of aluminium in 1 M HCl. Polarization and electrochemical impedance mea­surements were used for this purpose. Polarization curves showed that the compound is a mixed-type corrosion inhibitor. Also, the results showed an increase in inhibition efficiency as the concentration of the compound increased. The maximum corrosion inhibition effici­ency of approximately 81 % was reached at the concentration of 2 mg/L of the inhibitor. The results of the density functional theory method were consistent with the experimental results. The surface morphology of the samples was examined under atomic force microscopy

Impacts Potentiels du Changement Climatique sur les Rendements du Mil et du Sorgho Cultivés dans les Communes Rurales au Niger

Le changement climatique constitue une menace majeure pour les populations de l’Afrique de l’Ouest, en général et du sahel, en particulier. Le Niger est, pleinement, concerné par cette situation qui se traduit par une grande variabilité pluviométrique et une forte récurrence de sècheresses depuis les années 1970s. Cette étude analyse l’impact du changement climatique sur les rendements du mil et du sorgho dans les Communes rurales de Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria et Mokko, au Niger. Deux variétés de mil (HKP et SOMNO) et une de sorgho (Caudatum) ont été testées. Les données climatiques, utilisées sur la période de référence 1990-2020, proviennent de la Météorologie Nationale du Niger et de l’AGRHYMET Centre Climatique Régional pour l’Afrique de l’Ouest et le Sahel. Le modèle SARRA-H (V33) a été utilisé pour simuler les rendements des différentes variétés sur la période de référence et les périodes futures (2010-2039 et 2040-2069), sur la base des RCP4.5 et 8.5. Pour chaque Commune, les données des scénarios futurs de changement climatique ont été générées par 05 modèles globaux choisis parmi les 29 testés dans le cadre du projet AgMIP, en tenant compte de 05 conditions climatiques : Fraiche et Humide, Fraiche et Sèche, Moyenne, Chaude et Humide, Chaude et Sèche. Trois dates de semis (Dates précoce, moyenne et tardive), deux types de sols (sableux et sablo-argileux) et deux niveaux de fertilité du sol (Fertile et Non-Fertile) ont été considérés dans le modèle SARRA-H, pour chaque Commune. Les rendements simulés pour les variétés de mil et de sorgho sur la période 1990-2020 ont été plus élevés dans la Commune de Magaria et plus faibles dans celles de Balleyara et Illéla, en particulier pour un semis tardif fait sur un sol non-fertile. Les impacts des scénarios climatiques futurs se sont traduits par des baisses de rendements des variétés testées, allant de -5% à -70% selon les RCP, les horizons, les Communes, les types de sol et les dates de semis. La variété de mil photopériodique SOMNO a été la moins sensible aux scénarios climatiques testés et la variété de sorgho Caudatum la plus sensible. Ces résultats montrent que le choix des variétés et des dates de semis les plus adaptées aux conditions pédoclimatiques locales peut atténuer l’impact du changement climatique sur les rendements agricoles au Niger, notamment avec l’apport de fertilisants et le déploiement de mesures de réduction des impacts négatifs des déficits pluviométriques.   Climate change is a major threat to the populations of West Africa in general, and the Sahel in particular. Niger is fully concerned by this situation, which has resulted in high rainfall variability and recurrent droughts since the 1970s. This study analyzes the impact of climate change on millet and sorghum yields in the rural Communes of Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria and Mokko, Niger. Two millet varieties (HKP and SOMNO) and one sorghum variety (Caudatum) were tested. Climatic data for the reference period 1990-2020 were obtained from the Niger National Meteorology Service and the AGRHYMET Regional Climate Center for West Africa and the Sahel. The SARRA-H (V33) model was used to simulate yields of different varieties over the reference and future periods (2010-2039 and 2040-2069), based on RCP4.5 and 8.5. For each Commune, data for future climate change scenarios were generated by 05 global models chosen from the 29 tested as part of the AgMIP project, considering 05 climatic conditions: Cool and Humid, Cool and Dry, Medium, Hot and Humid, Hot and Dry. Three sowing dates (early, medium, and late), two soil types (sandy and sandy-clay) and two soil fertility levels (Fertile and Non-Fertile) were considered in the SARRA-H model, for each Commune. Simulated yields for millet and sorghum varieties over the period 1990-2020 were higher in the Commune of Magaria and lower in those of Balleyara and Illéla, particularly for late sowing on non-fertile soil. The impacts of future climate scenarios translated into yield reductions for the varieties tested, ranging from -5% to -70% depending on the RCP, horizons, Communes, soil types and sowing dates. The photoperiodic millet variety SOMNO was the least sensitive to the climatic scenarios tested, and the sorghum variety Caudatum the most sensitive. These results show that the choice of varieties and sowing dates best suited to local soil and climate conditions can mitigate the impact of climate change on agricultural yields in Niger, notably through the use of fertilizers and the deployment of measures to reduce the negative impacts of rainfall deficits

Impacts Potentiels du Changement Climatiques sur les Rendements des Principales Céréales (Mil et Sorgho) Cultivées au Niger : Cas des Communes de Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria et Mokko

Le changement climatique constitue une menace majeure pour la population de l’Afrique de l’Ouest et du sahel. Le Niger est pleinement concerné par cette situation se traduisant par une grande variabilité pluviométrique et une forte récurrence de sècheresses depuis les années 1970s. Cette étude, analyse l’impact du changement climatique sur les rendements du mil et du sorgho dans les communes rurales de Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria et Mokko au Niger. Deux variétés de mil (HKP et SOMNO) et une de sorgho (Caudatum) ont été testées. Les données climatiques utilisées sur la période de référence 1990-2020 proviennent de la Météorologie Nationale du Niger et de l’AGRHYMET Centre Climatique Régional pour l’Afrique de l’Ouest et le Sahel. Le modèle SARRA-H (V33) a été utilisé pour simuler les rendements des différentes variétés sur la période de référence et les périodes futures (2010-2039 et 2040-2069), sur la base des RCP4.5 et 8.5. Pour chaque commune, les données des scénarios futurs de changement climatique ont été générées par 05 modèles globaux choisis parmi les 29 testés dans le cadre du projet AgMIP, en tenant compte de 05 conditions climatiques : Fraiche et Humide, Fraiche et Sèche, Moyenne, Chaude et Humide, Chaude et Sèche. Trois dates de semis, deux types de sols et deux niveaux de fertilité du sol ont été considérées dans le modèle SARRA-H, pour chaque commune. Les rendements simulés pour les variétés de mil et de sorgho sur la période 1990-2020 ont été plus élevés dans la commune de Magaria et plus faibles dans celles de Balleyara et Illéla, en particulier pour un semis tardif fait sur un sol non-fertile. Les impacts des scénarios climatiques futurs se sont traduits par des baisses de rendements des variétés testées allant de -5% à -70% selon les RCP, les horizons, les communes, les types de sol et les dates de semis. La variété de mil photopériodique SOMNO a été la moins sensible aux scénarios climatiques testés et la variété de sorgho Caudatum la plus sensible. Ces résultats montrent que le choix des variétés et des dates de semis les plus adaptées aux conditions pédoclimatiques locales peut atténuer l’impact du changement climatique sur les rendements agricoles au Niger et au Sahel, notamment avec l’apport de fertilisants et le déploiement de mesures de réduction des impacts négatifs des déficits pluviométriques.   Climate change is a major threat to the population in West Africa and the Sahel. Niger is fully affected by this situation, resulting in high rainfall variability and a strong recurrence of droughts since the 1970s. This study analyzes the impact of climate change on millet and sorghum yields in the rural communes of Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria and Mokko in Niger. Two varieties of millet (HKP and SOMNO) and one of sorghum (Caudatum) were tested. The climate data used for the reference period 1990-2020 come from the Niger National Meteorology Service and the AGRHYMET Regional Climatic Center for West Africa and the Sahel. The SARRA-H (V33) crop model was used to simulate the yields of the different varieties over the reference period and future periods (2010-2039 and 2040-2069), based on RCP4.5 and 8.5. For each municipality, data on future climate change scenarios were generated by 5 global models chosen from the 29 tested as part of the AgMIP project, considering 5 climatic conditions: Cool and Humid, Cool and Dry, Average, Hot and Wet, Hot and Dry. Three sowing dates, two soil types and two soil fertility levels were considered in the SARRA-H model for each municipality. The simulated yields for millet and sorghum varieties over the period 1990-2020 were higher in the commune of Magaria and lower in those of Balleyara and Illéla, specially for the late sowing date on non-fertile soil. The impacts of future climate scenarios resulted in reductions in yields of the varieties tested ranging from -5% to -70% depending on the RCP, horizons, municipalities, soil types and sowing dates. The photoperiod sensitive millet variety SOMNO was the least sensitive to the climatic scenarios tested and the Caudatum sorghum variety the most sensitive. These results show that the choice of varieties and sowing dates best suited to local soil and climate conditions can reduce the impact of climate change on agricultural yields in Niger and the Sahel, particularly with the provision of fertilizers and the deployment of measures that reduce the negative impacts of rainfall deficits

Green and Fast Extraction of Chitin from Waste Shrimp Shells: Characterization and Application in the Removal of Congo Red Dye

Due to their detrimental and carcinogenic effects, synthetic organic dyes pose significant environmental and health risks. Consequently, addressing the bioremediation of industrial wastewater containing these organic dyes has become an urgent environmental concern. The adsorption using low-cost and green materials is one of the best alternative techniques for the removal of dyes. This study aims to investigate the use of chitin to eliminate Congo red (CR), an anionic dye, from wastewater. The chitin was produced from shrimp shell in a quick and environmentally friendly manner by utilizing a co-solvent (glycerol/citric acid (GLC)). The resulting adsorbent was characterized through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and FT-IR spectroscopy. The effectiveness of CR removal with chitin was studied with respect to contact time, adsorbent dose, initial pH, equilibrium isotherms, and kinetic and thermodynamic parameters. It was observed that variations in the dye concentration and pH significantly influenced the removal of CR with chitin. Under optimal operating conditions (pH = 7, contact time = 130 min, temperature = 50 °C), the adsorption capacity reached 29.69 ± 0.2 mg/g. The experimental data revealed that CR adsorption onto a chitin adsorbent is better represented by a Langmuir isotherm

Removal of Malachite Green Dye from Aqueous Solution by Catalytic Wet Oxidation Technique Using Ni/Kaolin as Catalyst

In this study, natural Algerian kaolin was used as a support and impregnated with nickel at different loading amounts (2 wt.%, 5 wt.%, and 7 wt.%) in order to prepare a supported catalyst. The wet impregnation technique was used in this preparation; nickel oxide (NiO) was the active phase precursor of the catalyst, and the catalysts were designated as follows: 2%, 5%, and 7% Ni/kaolin. These catalysts were put to the test in catalytic wet peroxide oxidation (CWPO) for degrading the organic contaminant malachite green dye (MG). Analytical techniques such as FTIR spectroscopy, X-ray diffraction, BET, and X-fluorescence were used to examine the structure, morphology, and chemical composition of the support and the produced catalysts. Several parameters, including temperature, catalytic dose, metal loading, hydrogen peroxide volume, and kinetic model were systematically investigated. The combination of improved parameters resulted in a significant increase in the catalytic activity, achieving a high removal rate of MG dye of 98.87%

A refined estimate of the malaria burden in Niger

<p>Abstract</p> <p>Background</p> <p>The health authorities of Niger have implemented several malaria prevention and control programmes in recent years. These interventions broadly follow WHO guidelines and international recommendations and are based on interventions that have proved successful in other parts of Africa. Most performance indicators are satisfactory but, paradoxically, despite the mobilization of considerable human and financial resources, the malaria-fighting programme in Niger seems to have stalled, as it has not yet yielded the expected significant decrease in malaria burden. Indeed, the number of malaria cases reported by the National Health Information System has actually increased by a factor of five over the last decade, from about 600,000 in 2000 to about 3,000,000 in 2010. One of the weaknesses of the national reporting system is that the recording of malaria cases is still based on a presumptive diagnosis approach, which overestimates malaria incidence.</p> <p>Methods</p> <p>An extensive nationwide survey was carried out to determine by microscopy and RDT testing, the proportion of febrile patients consulting at health facilities for suspected malaria actually suffering from the disease, as a means of assessing the magnitude of this problem and obtaining a better estimate of malaria morbidity in Niger.</p> <p>Results</p> <p>In total, 12,576 febrile patients were included in this study; 57% of the slides analysed were positive for the malaria parasite during the rainy season, when transmission rates are high, and 9% of the slides analysed were positive during the dry season, when transmission rates are lower. The replacement of microscopy methods by rapid diagnostic tests resulted in an even lower rate of confirmation, with only 42% of cases testing positive during the rainy season, and 4% during the dry season. Fever alone has a low predictive value, with a low specificity and sensitivity. These data highlight the absolute necessity of confirming all reported malaria cases by biological diagnosis methods, to increase the accuracy of the malaria indicators used in monitoring and evaluation processes and to improve patient care in the more remote areas of Niger. This country extends over a large range of latitudes, resulting in the existence of three major bioclimatic zones determining vector distribution and endemicity.</p> <p>Conclusion</p> <p>This survey showed that the number of cases of presumed malaria reported in health centres in Niger is largely overestimated. The results highlight inadequacies in the description of the malaria situation and disease risk in Niger, due to the over-diagnosis of malaria in patients with simple febrile illness. They point out the necessity of confirming all cases of suspected malaria by biological diagnosis methods and the need to take geographic constraints into account more effectively, to improve malaria control and to adapt the choice of diagnostic method to the epidemiological situation in the area concerned. Case confirmation will thus also require a change in behaviour, through the training of healthcare staff, the introduction of quality control, greater supervision of the integrated health centres, the implementation of good clinical practice and a general optimization of the use of available diagnostic methods.</p

Destructive quantum interference in <i>meta</i>-oligo(phenyleneethynylene) molecular wires with gold-graphene heterojunctions.

Quantum interference (QI) is well recognised as a significant contributing factor to the magnitude of molecular conductance values in both single-molecule and large area junctions. Numerous structure-property relationship studies have shown that para-connected oligo(phenyleneethynylene) (OPE) based molecular wires exemplify the impact of constructive quantum interference (CQI), whilst destructive quantum interference (DQI) effects are responsible for the orders of magnitude lower conductance of analogous meta-contacted OPE derivatives, despite the somewhat shorter effective tunnelling distance. Since molecular conductance is related to the value of the transmission function, evaluated at the electrode Fermi energy, T(EF), which in turn is influenced by the presence and relative energy of (anti)resonances, it follows that the relative single-molecule conductance of para- and meta-contacted OPE-type molecules is tuned both by the anchor group and the nature of the electrode materials used in the construction of molecular junctions (gold|molecule|gold vs. gold|molecule|graphene). It is shown here that whilst amine-contacted junctions show little influence of the electrode material on molecular conductance due to the similar electrode-molecule coupling through this anchor group to both types of electrodes, the weaker coupling between thiomethyl and ethynyl anchors and the graphene substrate electrode results in a relative enhancement of the DQI effect. This work highlights an additional parameter space to explore QI effects and establishes a new working model based on the electrode materials and anchor groups in modulating QI effects beyond the chemical structure of the molecular backbone

Increasing the uptake of Intermittent Preventive Treatment of malaria in pregnancy using Sulfadoxine-Pyrimethamine (IPTp-SP) through seasonal malaria chemoprevention channel delivery: protocol of a multicenter cluster randomized implementation trial in Mali and Burkina Faso

Background: The uptake of Intermittent Preventive Treatment of malaria in pregnancy using Sulfadoxine-Pyrimethamine (IPTp-SP) remains unacceptably low, with more than two-thirds of pregnant women in sub-Saharan Africa still not accessing the three or more doses recommended by the World Health Organisation (WHO). In contrast, the coverage of Seasonal Malaria Chemoprevention (SMC), a more recent strategy recommended by the WHO for malaria prevention in children under five years living in Sahelian countries with seasonal transmission, including Mali and Burkina-Faso, is high (up to 90%). We hypothesized that IPTp-SP delivery to pregnant women through SMC alongside antenatal care (ANC) will increase IPTp-SP coverage, boost ANC attendance, and increase public health impact. This protocol describes the approach to assess acceptability, feasibility, effectiveness, and cost-effectiveness of the integrated strategy. Methods and analysis: This is a multicentre, cluster-randomized, implementation trial of IPTp-SP delivery through ANC + SMC vs ANC alone in 40 health facilities and their catchment populations (20 clusters per arm). The intervention will consist of monthly administration of IPTp-SP through four monthly rounds of SMC during the malaria transmission season (July to October), for two consecutive years. Effectiveness of the strategy to increase coverage of three or more doses of IPTp-SP (IPTp3 +) will be assessed using household surveys and ANC exit interviews. Statistical analysis of IPT3 + and four or more ANC uptake will use a generalized linear mixed model. Feasibility and acceptability will be assessed through in-depth interviews and focus group discussions with health workers, pregnant women, and women with a child < 12 months. Discussion: This multicentre cluster randomized implementation trial powered to detect a 45% and 22% increase in IPTp-SP3 + uptake in Mali and Burkina-Faso, respectively, will generate evidence on the feasibility, acceptability, effectiveness, and cost-effectiveness of IPTp-SP delivered through the ANC + SMC channel. The intervention is designed to facilitate scalability and translation into policy by leveraging existing resources, while strengthening local capacities in research, health, and community institutions. Findings will inform the local national malaria control policies