143 research outputs found

    Computation of human health risk in surface water in Ado-Odo Ota, Ogun State, Nigeria

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    Heavy metals find their way into surface and groundwater due to degrading environmental conditions, and as such consistent monitoring to avoid the adverse health implications associated with the consumption of polluted water is required. This study examined the concentrations for Lead (Pb), Nickel (Ni), Zinc (Zn), Chromium (Cr), Cadmium (Cd), Copper (Cu) and Arsenic (As) in the Surface water of River Balogun in Ota, Ogun State, Nigeria during the wet season and estimated the human health risk resulting from prolonged consumption by children and adult of dissimilar age groups without treatment. Although there were persistent occurrence of Nickel (Ni), Copper (Cu), Zinc (Zn) and Arsenic (As) in all stations sampled, the health risk assessment conducted revealed that both population groups are more likely to be affected by high concentration levels of Arsenic than any other Heavy metal present

    Associação de marcadores moleculares SNP com o conteúdo de ácido linolênico em sementes de soja.

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    O objetivo deste trabalho foi validar a associação de marcadores moleculares do tipo ?single nucleotide polymorphism? (SNP) para os genes FAD3A, FAD3B e FAD3C com o conteúdo de ácido linolênico (18:3) em sementes de soja e analisar a influência dos parâmetros genéticos destes marcadores nesta característica. Foram genotipadas 185 progênies F2 derivadas do cruzamento entre A29 (mutante para os três genes FAD3, 1% de 18:3) e Tucunaré (genótipo selvagem, 11% de 18:3). Os marcadores moleculares para os genes FAD3A, FAD3B e FAD3C explicaram a variação do conteúdo de 18:3 nas populações segregantes F2 e F2:3. Além disso, as substituições alélicas no loco FAD3A proporcionam maiores variações no conteúdo de 18:3 que as substituições nos outros dois locos

    Análise do acúmulo de transcritos de ?-3-dessaturases em genótipos de soja contrastantes para o teor de ácido linolênico.

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    Os ácidos graxos poliinsaturados, como linoléico e linolênico, são os principais responsáveis pela alta instabilidade oxidativa a altas temperaturas do óleo destinado a frituras e à fabricação de biodiesel. A biossíntese de ácidos graxos poliinsaturados é catalisada pelas dessaturases. A -6-dessaturase converte ácido oléico (18:19) a linoléico (18:29,12) e a -3-dessaturase produz ácido linolênico (18:39,12,15) a partir de 18:29,12. Três genes principais (GmFAD3A, GmFAD3B e GmFAD3C) foram caracterizados como responsáveis pela produção de -3-dessaturase em soja. Os mecanismos precisos de regulação da produção de ácido linolênico ainda não são muito claros, o que dificulta o processo de obtenção de genótipos com baixo conteúdo desse ácido graxo. A análise molecular de mutantes de soja com baixo conteúdo de ácido linolênico poderá ajudar a elucidar tais mecanismos. Os objetivos principais deste trabalho foram determinar os níveis de mRNAs das principais -3-dessaturases, correlacionando-os com as concentrações relativas de ácidos linolênico durante a ontogenia da semente de soja em genótipos normais e mutantes. Para isso, foram utilizados três genótipos contrastantes para essa característica: A29, (~1% 18:315,12,9); N85-2176 (~3% 18:315,12,9) e Tucunaré (Variedade comercial, ~8% 18:315,12,9). As plantas foram cultivadas em casa de vegetação e suas sementes foram coletadas separadamente em 5 estádios de desenvolvimento de acordo com o peso úmido da semente: 1º estádio: 0 a 125 mg; 2º estádio: 126 a 250 mg; 3º estádio: 251 a 375 mg; 4º estádio: superior a 376 mg; 5 º estádio: semente madura. Os teores de ácidos graxos na fração óleo das sementes nos cinco estádios de desenvolvimento foram determinados por cromatografia gasosa e a expressão gênica, por PCR quantitativo, utilizando como o controle endógeno o gene da GAPDH (gliceraldeído-3-fosfato desidrogenase). De modo geral, o conteúdo de 18:39,12,15 decresceu drasticamente nos estádios iniciais em todos os genótipos. No entanto, não foi observada expressão diferencial entre os genes GmFAD3A, GmFAD3B e GmFAD3C, que pudessem explicar tais alterações. O genótipo A29, seguido de N85-2176, apresentou a menor concentração de 18:39,12,15 durante todo o desenvolvimento da semente. Estes genótipos apresentaram expressão praticamente nula do gene GmFAD3A. Além disso, A29 apresentou expressão reduzida do gene GmFAD3B. Assim, pelo menos em parte, os níveis de transcritos dos genes GmFAD3A e GmFAD3B explicam as diferenças na concentração de ácidos graxos da fração óleo em A29 e N85-2176. Apoio financeiro: CNPq e CAPES

    Cluster Development in a Transforming Economy: The Case of Motorcycle Spare Parts Firms in Nnewi, Anambra State of Nigeria

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    This paper examined the impact of cluster development in Nnewi, Anambra State of Nigeria. The estimated parsimonious model revealed that capital and labour were significant determinants of sales made by the firms while the cluster dummy variable was insignificant. This insignificance of the cluster dummy variable implied that, in terms of total sales, there was no significant difference between firms in the cluster and firms outside the cluster. For the profit model, we found that capital, labour and the cluster dummy were significant at 1% level. Capital, labour and cluster dummy have a positive relationship with firm profit. The positive coefficient of the cluster dummy variable indicated that the profit of firms in the cluster was significantly higher than that of the firms outside the cluster by about ₦31,050. It was therefore concluded that cluster residency made a significant difference in firm profit and recommended that government should encourage cluster development to accelerate the transformation of the economy

    Influência da posição da estaca no ramo ortotrópico na propagação de dois genótipos de Coffea Canephora Pierre irrigados pelo método de microaspersão por nebulização.

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    O uso de mudas de qualidade é fundamental para assegurar a produtividade das lavouras de café conilon. O uso de estacas provenientes de ramos ortotrópicos é a alternativa mais utilizada. Porém, ainda permanecem questões que devem ser investigadas, relativasa o processo de propagação, pois fatores exógenos e endógenos podem limitar a brotação, mesmo quando as condições sejam favoráveis para este processo. Assim, objetivou-se avaliar a produção de mudas e a taxa fotossintética, a partir de estacas provenientes de três diferentes posições no ramo ortotrópico, ápice, meio e base do ramo ortotrópico em dois genótipos de café conilon (12V e 748). Determinou-se a taxa fotossintética líquida (A-?mol CO2m-2s-1) aos 0, 13, 26 e 39 dias após o plantio das estacas (DAP) e o porcentual de estacas enraizadas e de estacas com brotaçãoque emitiram raiz aos 39 DAP. As curvas ajustadas pela equação de regressão não linear para a taxa fotossintética líquida indica um padrão de aclimatação e recuperação durante a produção de mudas. Não houve influência dos fatores genótipo e posição do ramo na fotossíntese. O genótipo 748 e os terços mediano e basaldo ramo ortotrópico apresentaram melhor enraizamento

    Deep Sequencing of MYC DNA-Binding Sites in Burkitt Lymphoma

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    BACKGROUND: MYC is a key transcription factor involved in central cellular processes such as regulation of the cell cycle, histone acetylation and ribosomal biogenesis. It is overexpressed in the majority of human tumors including aggressive B-cell lymphoma. Especially Burkitt lymphoma (BL) is a highlight example for MYC overexpression due to a chromosomal translocation involving the c-MYC gene. However, no genome-wide analysis of MYC-binding sites by chromatin immunoprecipitation (ChIP) followed by next generation sequencing (ChIP-Seq) has been conducted in BL so far. METHODOLOGY/PRINCIPAL FINDINGS: ChIP-Seq was performed on 5 BL cell lines with a MYC-specific antibody giving rise to 7,054 MYC-binding sites after bioinformatics analysis of a total of approx. 19 million sequence reads. In line with previous findings, binding sites accumulate in gene sets known to be involved in the cell cycle, ribosomal biogenesis, histone acetyltransferase and methyltransferase complexes demonstrating a regulatory role of MYC in these processes. Unexpectedly, MYC-binding sites also accumulate in many B-cell relevant genes. To assess the functional consequences of MYC binding, the ChIP-Seq data were supplemented with siRNA- mediated knock-downs of MYC in BL cell lines followed by gene expression profiling. Interestingly, amongst others, genes involved in the B-cell function were up-regulated in response to MYC silencing. CONCLUSION/SIGNIFICANCE: The 7,054 MYC-binding sites identified by our ChIP-Seq approach greatly extend the knowledge regarding MYC binding in BL and shed further light on the enormous complexity of the MYC regulatory network. Especially our observations that (i) many B-cell relevant genes are targeted by MYC and (ii) that MYC down-regulation leads to an up-regulation of B-cell genes highlight an interesting aspect of BL biology

    Beyond oxygen: complex regulation and activity of hypoxia inducible factors in pregnancy

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    In the first trimester the extravillous cytotrophoblast cells occlude the uterine spiral arterioles creating a low oxygen environment early in pregnancy, which is essential for pregnancy success. Paradoxically, shallow trophoblast invasion and defective vascular remodelling of the uterine spiral arteries in the first trimester may result in impaired placental perfusion and chronic placental ischemia and hypoxia later in gestation leading to adverse pregnancy outcomes. The hypoxia inducible factors (HIFs) are key mediators of the response to low oxygen. We aimed to elucidate mechanisms of regulation of HIFs and the role these may play in the control of placental differentiation, growth and function in both normal and pathological pregnancies. The Pubmed database was consulted for identification of the most relevant published articles. Search terms used were oxygen, placenta, trophoblast, pregnancy, HIF and hypoxia. The HIFs are able to function throughout all aspects of normal and abnormal placental differentiation, growth and function; during the first trimester (physiologically low oxygen), during mid-late gestation (where there is adequate supply of blood and oxygen to the placenta) and in pathological pregnancies complicated by placental hypoxia/ischemia. During normal pregnancy HIFs may respond to complex alterations in oxygen, hormones, cytokines and growth factors to regulate placental invasion, differentiation, transport and vascularization. In the ever-changing environment created during pregnancy, the HIFs appear to act as key mediators of placental development and function and thereby are likely to be important contributors to both normal and adverse pregnancy outcomes

    Four year follow-up of a randomised controlled trial comparing open and laparoscopic Nissen fundoplication in children

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    The article examines why some postconflict societies defer the recovery of those who forcibly disappeared as a result of political violence, even after a fully fledged democratic regime is consolidated. The prolonged silences in Cyprus and Spain contradict the experience of other countries such as Bosnia, Guatemala, and South Africa, where truth recovery for disappeared or missing persons was a central element of the transition to peace and democracy. Exhumations of mass graves containing the victims from the two periods of violence in Cyprus (1963-1974) and the Spanish Civil War (1936-1939) was delayed up until the early 2000s. Cyprus and Spain are well suited to explain both prolonged silences in transitional justice and the puzzling decision to become belated truth seekers. The article shows that in negotiated transitions, a subtle elite agreement links the noninstrumental use of the past with the imminent needs for political stability and nascent democratization. As time passes, selective silence becomes an entrenched feature of the political discourse and democratic institutions, acquiring a hegemonic status and prolonging the silencing of violence
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