Diagnostic de la contamination des eaux par les éléments traces métalliques dans la zone aurifère de Komabangou – Tillabéri, Niger

A Komabangou, dans la région de Tillabéri au Niger, l’or est exploité, durant des décennies, de manière artisanale avec l’utilisation des méthodes inadéquates et des substances peu respectueuses de l’environnement comme le mercure et le cyanure. La présente étude a pour objectif de déterminer les teneurs en éléments traces métalliques (ETM) des eaux de Komabangou afin de prévoir les risques environnementaux et sanitaires liés à leur utilisation. Ainsi, des prélèvements d’eau ont été effectués sur 8 sites d’extraction d’or, 4 forages et 3 mares, et leurs concentrations en métaux tels que As, Cd, Cu, Hg, Ni, Pb et Zn ont été analysées par spectrométrie de masse avec plasma à couplage inductif (ICP-MS). Les résultats obtenus révèlent une contamination importante de ces eaux et soulignent une variabilité significative des concentrations des ETM en fonction du métal analysé et du type d’eau. Dans la plupart des eaux, les valeurs limites réglementaires notamment celles de l’OMS ont été dépassées, cela pourrait poser des problèmes de toxicité pour les plantes, les animaux et la population locale. Par conséquent, la mise en place d’un programme de surveillance et de traitement des eaux contaminées de la zone de Komabangou serait nécessaire pour réduire les risques de contamination humaine.Mots clés : ETM, eaux, risque, site aurifère, Komabangou, Niger

Effect of wearing a helmet on the occurrence of head injuries in motorcycle riders in Benin: a case-control study

BACKGROUND: In Benin, motorcycles are the main means of transport for road users and are involved in more than half of crashes. This study aims to determine the effect of wearing a helmet on reducing head injuries in road crashes in Benin. METHODS: This case-control study took place in 2020 and focused on road trauma victims. The sample, consisting of 242 cases (trauma victims with head injuries) for 484 controls (without head injuries), was drawn from a database of traffic crash victims recruited from five hospitals across the country from July 2019 to January 2020. Four groups of independent variables were studied: socio-demographic and economic variables, history, behavioural variables including helmet use and road-related and environmental variables. To assess the shape of the association between the independent variables and the dependent variable, a descending step-by-step binary logistic regression model was performed using an explanatory approach. RESULTS: Fewer of the subjects with a head injury were wearing a helmet at the time of the crash 69.8% (95% CI = 63.6-75.6) compared to those without a head injury 90.3% (95% CI = 87.3-92.8). Adjusting for the other variables, subjects not wearing helmets were at greater risk of head injuries (OR = 3.8, 95% CI (2.5-5.7)); the head injury rating was 1.9 (95% CI = 1.2-3.3) times higher in subjects who were fatigued during the crash than among those who were not and 2.0 (95% CI = 1.2-3.3) times higher in subjects with no medical history. CONCLUSION: Failure to wear a helmet exposes motorcyclists to the risk of head injuries during crashes. It is important to increase awareness and better target such initiatives at the subjects most at risk

Corrigendum to “Synthesis of unnatural 2- and 3-deoxyfuranose analogues” [Tetrahedron Lett. 55 (2014) 3706–3708]

International audienc

Avaliação do sistema de pontuação para o diagnóstico da tuberculose na infância preconizado pelo Ministério da Saúde, Brasil Evaluation of a scoring system recommended by the Brazilian Ministry of Health for the diagnosis of childhood tuberculosis

A tuberculose é conhecida como uma das mais importantes causas de mortalidade no mundo. O diagnóstico da tuberculose na infância tem entre suas muitas dificuldades o achado bacteriológico do Mycobacterium tuberculosis. Este foi um estudo de caso-controle aninhado em uma coorte prospectiva com crianças que coletaram lavado gástrico em nível ambulatorial e hospitalar, com o objetivo de identificar se o sistema de pontuação para o diagnóstico de tuberculose em crianças negativas à baciloscopia, proposto pelo Ministério da Saúde, poderia ser utilizado como instrumento inicial de identificação do diagnóstico da tuberculose na infância. Um total de 108 crianças foi submetido ao lavado gástrico, sendo que 53 tiveram diagnóstico de tuberculose e 55 com diagnóstico descartado. O sistema de pontuação proposto pelo Ministério da Saúde para o diagnóstico de tuberculose em crianças com baciloscopia negativa apresentou uma boa sensibilidade em ambos os grupos estudados, sendo o melhor ponto de corte o critério 1 (possível diagnóstico de tuberculose) com sensibilidade de 92% podendo, então, ser usado como um auxiliar na investigação diagnóstica de crianças que se submeterão ao lavado gástrico. Nossa recomendação é que o sistema de pontuação do Ministério da Saúde seja utilizado nos serviços de saúde para auxiliar o médico a decidir sobre continuar ou não a investigação da tuberculose infantil, e não somente em crianças que já foram submetidas ao procedimento e tiveram suas amostras com resultado negativo.<br>Tuberculosis is currently one of the main causes of death in the world. One of the difficulties for tuberculosis diagnosis in childhood is the bacteriological identification of Mycobacterium tuberculosis. This nested case-control study aimed to compare the diagnostic values of a scoring system proposed by the Brazilian Ministry of Heath for diagnosis of childhood tuberculosis using gastric washing samples taken in the outpatient and hospital settings. A total of 108 children underwent gastric washing (53 with and 55 without tuberculosis). The scoring system proposed by the Brazilian Ministry of Heath for diagnosis of tuberculosis in children with negative sputum smears showed good sensitivity in both groups, and the best cutoff point was "1" (possible tuberculosis), with 92% sensitivity, thus feasible for use as an ancillary diagnostic test in children submitted to gastric washing. Our recommendation is that the Ministry of Health scoring system be used by health services to assist the physician in deciding on whether to continue the investigation of childhood tuberculosis, and not only in children who have already undergone the procedure and who have shown negative results

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento Whitening mechanism in injection molded polypropylene with TiO2 as pigment

Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de espectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento.<br>We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance