RESUMO
In this study, five types of modified Ziziphus joazeiro barks were investigated for the removal of Pb(II) ions from aqueous solutions. The samples tested were natural barks, natural powder, washed with water, ethanol at 80% (EE) and 0.5 N NaOH. Batch kinetics experiments were performed under the conditions: 24−25 °C, pH 5.5−5.8, 102 mg·L−1 Pb(NO3)2, 100 rpm and 0.1 g of adsorbent, and analyses of pHpzc and Fourier transform infrared spectroscopy. All adsorbents tested showed potential to remove Pb(II) ions, but the adsorbent washed by 0.5 N NaOH obtained the highest experimental performance (25.5 mg·g−1 at 30 min), while the EE had the least performance (20.4 mg·g−1 at 60 min), and maximum removals of 99.9%. The kinetic models pointed to a probable chemisorption due to the best fit of pseudo-second order and Elovich, and Boyd's model, suggesting that intraparticle diffusion limits the adsorption until the initial minutes of contact. The Langmuir isotherm fitted better to the experimental data for the NaOH adsorbent, with maximum adsorption capacity equal to 62.5 mg·g−1, although the Temkin model partially fitted, both suggesting the occurrence of chemisorption. The adsorption process is reversible (>81% at 20 min) and hence the adsorbents can be recycled and the Pb(II) ions recovered.
Assuntos
Poluentes Químicos da Água , Purificação da Água , Poluentes Químicos da Água/análise , Termodinâmica , Concentração de Íons de Hidrogênio , Adsorção , Purificação da Água/métodos , Cinética , Íons , Água , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
PURPOSE: To investigate the presence of the variants of lysyl oxygenase (LOX) and superoxide dismutase 1 (SOD1) genes in Brazilian patients with advanced keratoconus. METHODS: Donor genomic DNA extracted from blood samples was screened for 5'UTR, exonic LOX, and SOD1 variants in a subset of 26 patients presenting with advanced keratoconus (KISA > 1000% and I-S > 2.0) by Sanger sequencing. The impact of non-synonymous amino acid changes was evaluated by SIFT, PMUT, and PolyPhen algorithms. The Mutation Taster tool was used to evaluate the potential impact of formation of new donor and acceptor splice sites in the promoter region of affected volunteers carrying sequence variants. A 7-base SOD1 deletion (IVS2 + 50del7bp) previously associated with keratoconus was screened in 140 patients presenting classical keratoconus by gel fragment analysis, and positive samples were sequenced for confirmation. RESULTS: We found an unreported missense variant in LOX exon 6 in one heterozygous patient, leading to substitution of proline with threonine at residue 392 (p. Thr392Pro) of LOX protein sequence. This mutation was predicted to be potentially damaging to LOX protein. Another LOX variant, Arg158Gln, was also detected in another patient but predicted to be non-pathogenic. Two additional new polymorphisms in LOX 5'UTR region (-116C > T and -58C > T) were found in two patients presenting with advanced keratoconus and were predicted to modulate or create donor/acceptor splice sites in LOX transcripts. Additionally, SOD1 deletion was detected in one patient presenting with severe keratoconus, not in control samples. CONCLUSION: We described three novel LOX polymorphisms identified for the first time in Brazilian patients with advanced keratoconus, as well as a previously described SOD1 deletion strongly associated with keratoconus. A possible role of these variants in modulating transcript levels in the cornea of affected individual requires further investigation.
RESUMO
PURPOSE: To screen visual system homeobox 1 (VSX1) gene in Brazilian subjects affected with keratoconus (KCN). METHODS: Seventy-three patients with KCN and 106 healthy controls were enrolled in this study. Patients were diagnosed with KCN based on eye examination and corneal topographic features according to Rabinowitz's criteria (K > 47.2, I-S > 1.4 and KISA > 100%). DNA from blood samples was extracted from donors, and the exons and exon-intron boundaries of VSX1 were sequenced. The potential impact of the identified amino acid changes was assessed with Poly-Phen2, SIFT, and PMUT analysis tools. Genotyping was confirmed by RLFP technique, which was also applied to genotype non-affected individuals. RESULTS: We found three non-synonymous substitutions (L68H, R131S, and D105E) in VSX1 exon 1, with L68H mutation as a novel variation in this gene. In silico analysis indicated that all variations found were predicted to be probably damaging to VSX1 structure and function. Examination of R131S and L68H variations segregating in one family suggested a strong effect of these variations in increasing disease severity in the proband, which presented bilateral KCN leading to corneal grafting before the age of sixteen. We found a novel synonymous substitution (P79P) and two previously described exonic polymorphisms, with unknown roles in VSX1 pathogenesis. CONCLUSION: VSX1 polymorphisms found in the Brazilian population support a genetic component in KCN pathogenesis. L68H is a novel mutation, and the phenotypic data suggest that this mutation might enhance disease severity when combined with other polymorphisms. However, further investigations are needed.
RESUMO
Water is a basic natural resource for the maintenance of life and is indispensable in all human activities. Since it is a limited natural resource, concern on the conservation of its quality is high, coupled with efficacious mechanisms that may diminish negative environmental impacts. Current analysis applies the Water Quality Index (WQI) for hydraulic barriers in the urban stretch of Mossoró RN Brazil and verifies the water body conditions according to usage classes, with special reference to predominant factors and previous classification of the water body. Collection of water for analysis of WQI parameters was undertaken in July 2010 in three barriers within the urban stretch and geo-referenced for the indication of critical sites. Possible exploratory activities linked to the contamination of the water body were listed. An evaluation of rates was undertaken and compared with current legislation guidelines. According to CONAMA n. 357/2005, results showed that analyses during the dry period referred to the salinity of the water body when related to preponderant usage indexes, or Class 1. Total phosphorus failed to comply with rates when parameters were analyzed one by one and compared to standards established by CONAMA n. 357/2005. Water was of good quality at the first barrier and fair in the others from the entrance of the city and downstream, due to the great load of home
A água é um recurso natural fundamental para a vida, sendo indispensável em praticamente todas as atividades antrópicas. Sendo um recurso natural limitado, a preocupação com a conservação da qualidade da água tornou-se crescente, concomitante a procura de mecanismos eficazes, capazes de mitigar os impactos ambientais negativos. O presente trabalho tem como objetivo aplicar o Índice de Qualidade de Água (IQA) aos barramentos hidráulicos situados no trecho urbano do município de Mossoró-RN, sendo, posteriormente, feita a verificação da condição do corpo hídrico de acordo com as classes de uso, ressaltando os preponderantes, além da classificação prévia do corpo hídrico. As coletas de água para análise dos parâmetros referentes ao IQA foram realizadas no mês de julho de 2010, distribuídas em três barramentos situados no trecho urbano, sendo georreferenciadas, subsidiando a indicação dos pontos críticos. Foram elencadas as possíveis atividades exploratórias contribuintes com a contaminação do corpo hídrico. Por fim realizada a avaliação individual dos valores obtidos comparados com as diretrizes das legislações vigentes. Com os resultados obtidos, baseado na resolução CONAMA nº 357/2005, verificou-se que as análises para o período de estiagem, evidenciam a condição do corpo hídrico quanto a salinidade como água salobra, em relação aos usos preponderantes, Classe 1. Entretanto, quan
RESUMO
Water is a basic natural resource for the maintenance of life and is indispensable in all human activities. Since it is a limited natural resource, concern on the conservation of its quality is high, coupled with efficacious mechanisms that may diminish negative environmental impacts. Current analysis applies the Water Quality Index (WQI) for hydraulic barriers in the urban stretch of Mossoró RN Brazil and verifies the water body conditions according to usage classes, with special reference to predominant factors and previous classification of the water body. Collection of water for analysis of WQI parameters was undertaken in July 2010 in three barriers within the urban stretch and geo-referenced for the indication of critical sites. Possible exploratory activities linked to the contamination of the water body were listed. An evaluation of rates was undertaken and compared with current legislation guidelines. According to CONAMA n. 357/2005, results showed that analyses during the dry period referred to the salinity of the water body when related to preponderant usage indexes, or Class 1. Total phosphorus failed to comply with rates when parameters were analyzed one by one and compared to standards established by CONAMA n. 357/2005. Water was of good quality at the first barrier and fair in the others from the entrance of the city and downstream, due to the great load of home
A água é um recurso natural fundamental para a vida, sendo indispensável em praticamente todas as atividades antrópicas. Sendo um recurso natural limitado, a preocupação com a conservação da qualidade da água tornou-se crescente, concomitante a procura de mecanismos eficazes, capazes de mitigar os impactos ambientais negativos. O presente trabalho tem como objetivo aplicar o Índice de Qualidade de Água (IQA) aos barramentos hidráulicos situados no trecho urbano do município de Mossoró-RN, sendo, posteriormente, feita a verificação da condição do corpo hídrico de acordo com as classes de uso, ressaltando os preponderantes, além da classificação prévia do corpo hídrico. As coletas de água para análise dos parâmetros referentes ao IQA foram realizadas no mês de julho de 2010, distribuídas em três barramentos situados no trecho urbano, sendo georreferenciadas, subsidiando a indicação dos pontos críticos. Foram elencadas as possíveis atividades exploratórias contribuintes com a contaminação do corpo hídrico. Por fim realizada a avaliação individual dos valores obtidos comparados com as diretrizes das legislações vigentes. Com os resultados obtidos, baseado na resolução CONAMA nº 357/2005, verificou-se que as análises para o período de estiagem, evidenciam a condição do corpo hídrico quanto a salinidade como água salobra, em relação aos usos preponderantes, Classe 1. Entretanto, quan