Os Processos Oxidativos Avançados (ou Processos Avançados de Oxidação), conhecidos pela sigla POA's, são processos que se baseiam na geração de radicais livres, principalmente o radical hidroxil (•OH), que possui alto poder oxidante e pode promover a degradação de vários compostos poluentes eficientemente. Esses processos têm obtido grande atenção devido ao aumento da complexidade e dificuldade no tratamento de águas residuárias, o que tem sido motivo para a busca de novas metodologias visando a remediação desses rejeitos. Diante disso, o presente trabalho teve por objetivo relacionar quatro metodologias de tratamento via Oxidação Avançada: processos envolvendo H2O2, sistemas Fenton e Foto-Fenton, Fotocatálise Heterogênea e sistemas fundamentados na utilização de ozônio. A revisão realizada descreve os principais fundamentos destes processos e discute mecanismos de degradação de poluentes orgânicos. As principais vantagens da utilização destes processos estão em sua inespecificidade, podendo ser utilizados para degradar substratos de qualquer natureza química, na possibilidade de emprego para degradar poluentes cuja concentração seja muito baixa (μg L-1) e na não geração de resíduos. Por outro lado, algumas desvantagens são observadas, como os custos que podem ser elevados e a formação de subprodutos de reação.
The incidence of 21-hydroxylase deficiency (CYP21 D) congenital adrenal hyperplasia (CAH) in Brazil is purportedly one of the highest in the world (1:7,533). However, this information is not based on official data. The aim of this study was to determine the incidence of CYP21 D CAH in the state of Goiás, Brazil, based on the 2005 results of government-funded mandatory screening. Of the live births during this period, 92.95% were screened by heel-prick capillary 17alpha-hydroxyprogesterone (17-OHP). Of these, 82,343 were normal, 28 were at high risk for CAH and 232 at low risk for CAH. Eight cases, all from the high risk group, were confirmed. Eight asymptomatic children at 6-18 months of age still have high 17-OHP levels and await diagnostic definition. Based on the number of confirmed CYP21 D CAH cases among the 82,603 screened, the estimated annual incidence of the disease was 1:10,325, lower than the previously reported rate in Brazil.
Neonatal screening for congenital adrenal hyperplasia (CAH) is useful in diagnosing salt wasting form (SW). However, there are difficulties in interpreting positive results in asymptomatic newborns. The main objective is to analyze genotyping as a confirmatory test in children with neonatal positive results. Patients comprised 23 CAH children and 19 asymptomatic infants with persistently elevated 17-hydroxyprogesterone (17OHP) levels. CYP21A2 gene was sequenced and genotypes were grouped according to the enzymatic activity of the less severe allele: A1 null, A2 < 2%, B 3-7%, C > 20%. Twenty-one children with neonatal symptoms and/or 17OHP levels > 80 ng/ml carried A genotypes, except two virilized girls (17OHP < 50 ng/ml) without CAH genotypes. Patients carrying SW genotypes (A1, A2) and low serum sodium levels presented with neonatal 17OHP > 200 ng/ml. Three asymptomatic boys carried simple virilizing genotypes (A2 and B): in two, the symptoms began at 18 months; another two asymptomatic boys had nonclassical genotypes (C). The remaining 14 patients did not present CAH genotypes, and their 17OHP levels were normalized by 14 months of age. Molecular analysis is useful as a confirmatory test of CAH, mainly in boys. It can predict clinical course, identify false-positives and help distinguish between clinical forms of CAH.
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