48 research outputs found

    Optimal sulphuric acid production using Acidithiobacillus caldus (DSM 8584): Bioprocess design for application in ion-exchange

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    An optimised bioprocess was designed for the optimal production of sulphuric acid for application in an isotope recovery ion-exchange process. Firstly, the production of sulphuric acid (H2SO4) was optimised in aerated batch bioreactors using Acidithiobacillus caldus (DSM 8584) using elemental sulphur, achieving H2SO4 concentration of >0.4 to ~0.5 M (0.45 M average) with the following bioprocess parameters: product yield of 3.06 (Yp/s), oxygen uptake rate of 1.35 g/L.day (OUR), 52% sulphur conversion at a rate of 0.83 g/L.day (dS°/dt), achieving a sulphuric acid production rate of 2.76 g/L.day (dP/dt), while the oxidation of elemental sulphur per dissolved oxygen consumed was 0.67 g S°/g O2. Secondly, after 80% (v/v) moisture loss from the recovered biological H2SO4 titres, the acid solution was used for the recovery of nuclear grade lithium 7 (7Li+) from a degraded resin, achieving >80% recovery rate within two bed volumes (60 ml) at an averaged desorption rate K¯ of 0.1829 min -1 and eluent rate of 6.65 ml.min-1 in comparison to the ~60% 7Li+ recovery rate using a commercial grade mineral H2SO4 using similar operational ion-exchange reactor parameters. The designed bioprocess proved to be an effective and environmentally friendly bioprocess for the recovery of valuable metals adsorbed onto ion-exchange resin.Keywords: Acidithiobacillus caldus, sulphuric acid, ion-exchange, desorption, lithium 7 isotop

    Genome-wide Associations Reveal Human-Mouse Genetic Convergence and Modifiers of Myogenesis, CPNE1 and STC2

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    Acknowledgements The authors would like to acknowledge Dr David A. Blizard for his role in the development of the ideas that led to this study and feedback on the manuscript, Professor Helen Macdonald for valuable advice on study design, Dr Leslie R. Noble for help with the UK Biobank data, and Dr Joseph P. Gyekis for help genotyping cohort 2 mice. The authors would like to acknowledge funding from the University of Aberdeen for the Maxwell computer cluster, the Elphinstone and IMS studentship for AIHC; a Schweppe Foundation Career Development Award (AAP), and the NIH (NIAMS (AL: R01AR056280) and NIDA (AAP:R01DA021336, AAP:R21DA024845, AAP:T32MH020065, NMG:F31DA03635803), NIGMS (NMG:T32GM007197), NHGRI (MA:R01HG002899))Peer reviewedPostprin

    Spatial clustering of childhood leukaemia: summary results from the EUROCLUS project.

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    The interpretation of reports of clusters of childhood leukaemia is difficult, first because little is known about the causes of the disease, and second because there is insufficient information on whether cases show a generalized tendency to cluster geographically. The EUROCLUS project is a European collaborative study whose primary objective is to determine whether the residence locations of cases at diagnosis show a general tendency towards spatial clustering. The second objective is to interpret any patterns observed and, in particular, to see if clustering can be explained in terms of either infectious agents or environmental hazards as aetiological agents. The spatial distribution of 13351 cases of childhood leukaemia diagnosed in 17 countries between 1980 and 1989 has been analysed using the Potthoff-Whittinghill method. The overall results show statistically significant evidence of clustering of total childhood leukaemia within small census areas (P=0.03) but the magnitude of the clustering is small (extra-Poisson component of variance (%) = 1.7 with 90% confidence interval 0.2-3.1). The clustering is most marked in areas that have intermediate population density (150-499 persons km[-2]). It cannot be attributed to any specific age group at diagnosis or cell type and involves spatial aggregation of cases of different ages and cell types. The results indicate that intense clusters are a rare phenomenon that merit careful investigation, although aetiological insights are more likely to come from investigation of large numbers of cases. We present a method for detecting clustering that is simple and readily available to cancer registries and similar groups

    The transcription factor Spores Absent A is a PKA dependent inducer of Dictyostelium sporulation

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    Abstract Sporulation in Dictyostelium fruiting bodies evolved from amoebozoan encystation with both being induced by cAMP acting on PKA, but with downstream components still being unknown. Using tagged mutagenesis to find missing pathway components, we identified a sporeless mutant defective in a nuclear protein, SpaA. Expression of prespore genes was strongly reduced in spaA- cells, while expression of many spore stage genes was absent. Chromatin immunoprecipitation (ChIP) of a SpaA-YFP gene fusion showed that (pre)spore gene promoters bind directly to SpaA, identifying SpaA as a transcriptional regulator. SpaA dependent spore gene expression required PKA in vivo and was stimulated in vitro by the membrane-permeant PKA agonist 8Br-cAMP. The PKA agonist also promoted SpaA binding to (pre)spore promoters, placing SpaA downstream of PKA. Sequencing of SpaA-YFP ChIPed DNA fragments revealed that SpaA binds at least 117 (pre)spore promoters, including those of other transcription factors that activate some spore genes. These factors are not in turn required for spaA expression, identifying SpaA as the major trancriptional inducer of sporulation

    The Dictyostelium discoideum acaA Gene Is Transcribed from Alternative Promoters during Aggregation and Multicellular Development

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    Background: Extracellular cAMP is a key extracellular signaling molecule that regulates aggregation, cell differentiation and morphogenesis during multi-cellular development of the social amoeba Dictyostelium discoideum. This molecule is produced by three different adenylyl cyclases, encoded by the genes acaA, acrA and acgA, expressed at different stages of development and in different structures. Methodology/Principal Findings: This article describes the characterization of the promoter region of the acaA gene, showing that it is transcribed from three different alternative promoters. The distal promoter, promoter 1, is active during the aggregation process while the more proximal promoters are active in tip-organiser and posterior regions of the structures. A DNA fragment containing the three promoters drove expression to these same regions and similar results were obtained by in situ hybridization. Analyses of mRNA expression by quantitative RT-PCR with specific primers for each of the three transcripts also demonstrated their different temporal patterns of expression. Conclusions/Significance: The existence of an aggregation-specific promoter can be associated with the use of cAMP as chemo-attractant molecule, which is specific for some Dictyostelium species. Expression at late developmental stages indicates that adenylyl cyclase A might play a more important role in post-aggregative development than previously considered

    Social factors influencing child health in Ghana

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    Objectives Social factors have profound effects on health. Children are especially vulnerable to social influences, particularly in their early years. Adverse social exposures in childhood can lead to chronic disorders later in life. Here, we sought to identify and evaluate the impact of social factors on child health in Ghana. As Ghana is unlikely to achieve the Millennium Development Goals’ target of reducing child mortality by two-thirds between 1990 and 2015, we deemed it necessary to identify social determinants that might have contributed to the non-realisation of this goal. Methods ScienceDirect, PubMed, MEDLINE via EBSCO and Google Scholar were searched for published articles reporting on the influence of social factors on child health in Ghana. After screening the 98 articles identified, 34 of them that met our inclusion criteria were selected for qualitative review. Results Major social factors influencing child health in the country include maternal education, rural-urban disparities (place of residence), family income (wealth/poverty) and high dependency (multiparousity). These factors are associated with child mortality, nutritional status of children, completion of immunisation programmes, health-seeking behaviour and hygiene practices. Conclusions Several social factors influence child health outcomes in Ghana. Developing more effective responses to these social determinants would require sustainable efforts from all stakeholders including the Government, healthcare providers and families. We recommend the development of interventions that would support families through direct social support initiatives aimed at alleviating poverty and inequality, and indirect approaches targeted at eliminating the dependence of poor health outcomes on social factors. Importantly, the expansion of quality free education interventions to improve would-be-mother’s health knowledge is emphasised

    Transmembrane signalling in eukaryotes: a comparison between higher and lower eukaryotes

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