ABSTRACT
RESUMO Este estudo avaliou as propriedades físico-químicas envolvidas no processo de adsorção para subsidiar o potencial uso de biocarvão produzido com folhas secas de amendoeira-da-praia, Terminalia catappa, como remediador em águas contaminadas com metais. O biocarvão utilizado foi produzido por conversão à baixa temperatura e caracterizado por apresentar bandas de O-H, CH2, C-O e C-O-C; teores de 48,8% de carbono, 46,6% de oxigênio, 3,3% de hidrogênio e demais entre enxofre e nitrogênio; presença de macroporos e passado em peneira (100 mesh). Para o estudo, preparou-se um coquetel de radiotraçadores (Co-57, Mn-54 e Zn-65), que foi adicionado à água deionizada e massas de biocarvão com o objetivo de obter parâmetros tais como pH, tempo de equilíbrio e capacidade de adsorção por meio das isotermas de Langmuir e Freundlich. O detector de Germânio Hiperpuro foi utilizado para quantificar as atividades dos radiotraçadores por meio da técnica de espectroscopia gama para geração e tratamento de dados. Os resultados obtidos mostraram aumento na adsorção do pH 3,8 em diante e tempo de equilíbrio de 30 minutos ou mais. As isotermas de Langmuir e Freundlich construídas apresentaram bons ajustes, com valores de n maiores que 1, indicando preferência dos metais pelo material adsorvente. Além disso, levando-se em conta a competição pelos sítios ativos e a concentração inicial das soluções (ordem de picogramas), foram encontradas capacidades de adsorção de 1,273 ng.g-1 para o Zn-65, de 3.271 ng.g-1 para o Co-57 e de 9,026 ng.g-1 para o Mn-54.
ABSTRACT This study evaluated the physical-chemical properties of the adsorption process in biochar produced from dry leaves of beach-almond, Terminalia catappa, as a useful tool for remediation purposes in water contaminated with metals. The biochar was characterized by having: bands of O-H, CH2, C-O, and C-O-C; contents of 48.8% carbon, 46.6% oxygen, 3.3% hydrogen and the others between sulfur and nitrogen; the presence of macropores; and being sieved (100 mesh). Parameters such as pH, equilibrium time and adsorption capacity by the Langmuir and Freundlich isotherms were determined from experiments using a radiotracer cocktail (Co-57, Mn-54 and Zn-65) which was added to deionized water and a constants mass of biochar. The high-purity germanium detector (HPGe) was used to quantify the radiotracer activity by gamma spectroscopy. The results showed better adsorption from pH 3.8 and 30 minutes equilibrium time. The Langmuir and Freundlich isotherms had a good model fit, with n values higher than 1, and showed affinity between the metals and the biochar. The adsorption capacities of Zn-65, Co-57 and Mn-54 were 1.273 ng.g−1, 3.271 ng.g−1 and 9.026 ng.g−1, respectively.
ABSTRACT
Leishmaniasis remains one of the world's leading infectious diseases and a public health problem for Bahia and Brazil. We made a retrospective cohort study of leishmaniasis cases reported between 2007 and 2016 in the Barreiras city, an important agribusiness city whose urbanization process was recent. Leishmaniasis presented epidemiological data with similar characteristics of the disease in other regions of the Brazil, that is, with the highest prevalence of visceral leishmaniasis found in children, while cutaneous leishmaniais was found in adults. The disease presented an urban configuration with wide distribution in the Barreiras city. We found the vectors of the different clinical forms of the disease occurring in the urban area of Barreiras city, particularly the sand fly of the Lutzmyia longipalpis, Evandromyia sallesi and Nyssomyia intermedia species. More studies will be necessary to indentify whether these species are really incriminated in the urban transmission of the parasites in the urban areas. This study indicates the places of the spatio-temporal greatest occurrence and transmission of the disease in the urban zones of Barreiras city.
Subject(s)
Leishmaniasis , Psychodidae , Animals , Brazil/epidemiology , Humans , Leishmaniasis/epidemiology , Psychodidae/parasitology , Retrospective Studies , UrbanizationABSTRACT
We describe the relationship between lesion outcome and histopathological hallmarks in susceptible (BALB/c) and resistant (C57BL/6 and IL-4-deficient BALB/c) mouse strains over the course of a 12-week-infection with Leishmania major in the ear. The infiltration of mononuclear cells and polymorphonuclear cells occurred within 6 h and mononuclear cells predominated one week post-infection. Permissive intracellular growth of the pathogen was associated with non-healing lesions. In contrast, tissue damage and clearance of the parasite was observed in healing lesions and was associated with inducible nitric oxide synthase expression. The identification of the structural components of tissue reaction to the parasite in this study furthers our understanding of subjacent immune effector mechanisms.
Subject(s)
Ear, External/parasitology , Interleukin-4/immunology , Leishmania major , Leishmaniasis, Cutaneous/pathology , Nitric Oxide Synthase Type II/immunology , Animals , Disease Susceptibility , Ear, External/pathology , Female , Interleukin-4/deficiency , Leishmaniasis, Cutaneous/immunology , Male , Mast Cells/pathology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BLABSTRACT
We describe the relationship between lesion outcome and histopathological hallmarks in susceptible (BALB/c) and resistant (C57BL/6 and IL-4-deficient BALB/c) mouse strains over the course of a 12-week-infection with Leishmania major in the ear. The infiltration of mononuclear cells and polymorphonuclear cells occurred within 6 h and mononuclear cells predominated one week post-infection. Permissive intracellular growth of the pathogen was associated with non-healing lesions. In contrast, tissue damage and clearance of the parasite was observed in healing lesions and was associated with inducible nitric oxide synthase expression. The identification of the structural components of tissue reaction to the parasite in this study furthers our understanding of subjacent immune effector mechanisms.
