Navegando por Assunto "Iron"

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Acesso aberto (Open Access)
Efeitos do quelante de ferro, a deferoxamina, sobre as alterações oxidativas e cognitivas induzidas pela dapsona, em modelo animal
(Universidade Federal do Pará, 2020-11-17) MENDES, Paulo Fernando Santos; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390; https://orcid.org/ 0000-0002-3328-5650
Dapsone (DDS) is an antibiotic that works by inhibiting folate synthesis, showing good bacteriostatic action. However, it can lead to severe adverse events such as neurological disorders, methemoglobinemia and hemolysis. These hematological disorders lead to the alteration of iron homeostasis and thereby increase the formation of ROS that can lead to cellular and tissue damage. This change plays an important role in neurodegenerative diseases, whether as a causative and / or intensifying agent in these diseases. In this context, we used an iron chelator, deferoxamine (DFX), to evaluate its effects on the formation of ROS triggered by the increase in free iron induced by the use of DDS. For this, the alteration of iron homeostasis was induced in Swiss mice, using DDS, followed by the administration of DFX. After that, oxidative stress parameters were measured in the hippocampus and plasma, in addition to the measurement of iron levels. Our results showed that DDS decreased TEAC and that DFX treatment was restored. In addition, DDS decreased GSH and DFX treatment was restored. It increased the LPO and the treatment with DFX reduced this effect, increased the concentration of iron and that was reversed by the treatment with DFX. Additionally, the animals were submitted to the Morris water maze, where our results showed that animals treated with DDS showed a reduction in mnemonic capacity and that treatment with DFX was able to inhibit loss. These results suggest that the use of iron chelators may be an alternative to reduce the effects of iron accumulation on the nervous system observed in neurodegenerative diseases.
Acesso aberto (Open Access)
Influência da temperatura de calcinação na redução da hematita e na liberação do titânio na lama vermelha (resíduo do processo bayer)
(Universidade Federal do Pará, 2016-12-26) VIEGAS, Bruno Marques; MAGALHÃES, Edilson Marques; CV: http://lattes.cnpq.br/1570353513360972; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
In this work a technological route was proposed aiming at the reduction of hematite to magnetite and the release of titanium present in red mud from Hydro Alunorte. The fluorescence and x ray diffraction analysis showed that the red mud presents in their composition approximately 5% of titanium oxide as anatase and 28% of iron oxide in the forms of hematite and goethite. Therefore, the proposed route will enable the obtainment of a material with magnetic characteristics which can be used as source of titanium after extraction of iron compounds in magnetic form. So, the reduction of the hematite to the magnetite was carried out by thermal treatment in a reducing atmosphere. To accomplish this, mixtures were made in different concentrations of red mud and charcoal. These mixtures were calcined at temperatures of 500, 600 and 1000 ° C for two hours. Then, X ray diffraction analysis were performed, which showed that the hematite was reduced to magnetite in all experimental conditions and, for the mixtures calcined at 1000 ° C, besides the formation of the magnetite, there was also the formation of maghemite. Through analysis of Raman spectroscopy and scanning electron microscopy, it was verified that for calcination temperatures of 500 to 600° C titanium remained in the free form of anatase, but for the calcination carried out at 1000° C this passed to the combined form with iron (ilmenite). The technological route allowed the formation of magnetite from the red mud, which can be extracted with the use of a magnetic separator.