738 research outputs found

    Estimation de la biomasse bactérienne dans les effluents urbains par mesure de l'activité exoprotéolytique potentielle

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    Des études récentes ont montré que, lors du rejet d'eaux usées dans une rivière, la quantité de biomasse bactérienne hétérotrophe amenée par les effluents influence considérablement la cinétique de biodégradation de la matière organique dans la rivière et donc les caractéristiques du déficit d'oxygène généralement observé dans le milieu naturel en aval du rejet. La mesure de la biomasse bactérienne contenue dans un rejet domestique est donc nécessaire afin de bien comprendre la cinétique de biodégradation. Cette biomasse peut être estimée en microscopie à épifluorescence après coloration des cellules bactériennes par un fluorochrome. Cette technique appliquée aux eaux usées est néanmoins difficile et fastidieuse. Dans cette étude, une méthode alternative à l'estimation de la biomasse bactérienne dans les eaux usées a été testée ; elle consiste à mesurer l'activité exoprotéolytique potentielle (AEP) des bactéries. Nous avons montré qu'il existait, dans les eaux usées, une corrélation significative entre l'AEP et la biomasse bactérienne estimée en microscopie à épifluorescence ce qui permet d'utiliser l'AEP pour estimer facilement et rapidement la biomasse bactérienne dans ce type d'échantillon. Comme exemple d'application, des mesures d'AEP nous ont permis d'étudier l'impact de divers types de traitement dans plusieurs stations d'épuration sur la biomasse bactérienne hétérotrophe des effluents urbains. Sur base de ces mesures, les charges spécifiques en biomasse bactérienne (charge par habitant et par jour) des eaux brutes et traitées ont pu être calculées.Recent studies have shown that when wastewaters are discharged into a river, heterotrophic bacterial biomass in the effluent exerts considerable influence on the biodegradation kinetics of organic matter and provokes the oxygen deficits often observed downstream from outfalls. Quantification of bacterial biomass in wastewaters is required for a good understanding the biodegradation kinetics. Bacterial biomass can be estimated by epifluorescence microscopy after staining cells with fluorochrome. Applying this technique to wastewater samples, however, is painstaking and difficult. In this study, an alternative method for estimating bacterial biomass in wastewaters was tested; it consists of measuring the potential exoproteolytic activity (PEA) of bacteria. Previous studies on other types of aquatic systems have shown that bacterial biomass can be estimated from PEA. After optimising the PEA procedure for use with wastewater, we found a significant correlation between PEA and the bacterial biomass estimated by epifluorescence microscopy. This opens the way for PEA measurements for rapid and easy estimates of bacterial biomass in wastewaters. As an example of the application of this technique, the impact of wastewater treatment on bacterial biomass in effluent was investigated at various treatment plants. On the basis of our procedure, specific loads of bacterial biomass (load per inhabitant and per day) were calculated for raw and treated wastewaters

    Theme Analysis of Flora Nwapa’s Never Again: A Systemic Functional Approach

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    This paper deals with theme analysis of Flora Nwapa’s Never Again. The theory that underpins this study is systemic functional linguistics, which is one of the approaches proposed by scholars such as M.A.K Halliday, S. Eggins, J. R. Martin, R. Fowler, J. D. Benson to mention but a very few, for the study of language and its function(s). In this system, the study of language involves three functional labels: experiential, interpersonal and textual meanings. This study aims at describing and analysing linguistic features which connote textual meaning in Never Again so as to have a deep understanding of the novel and provide a new interpretation of it. It also aims at uncovering the deep messages conveyed through the novel. Both quantitative and qualitative methods have been used in this study. Thus, two extracts have been selected from Never Again and systemic functional linguistic theories have been applied to each of them for the purpose of exploring how language is used to organise itself. The study of the internal organisation and communicative nature of the selected Texts has enabled the researchers to come up with valuable findings. Indeed, through Mood adjuncts that conflate interpersonal themes, participants in Text 1 have expressed particular attitudes and judgments about the limited power of women and the roles of women and children during war whereas those in Text 2 have expressed a high degree of certainty and inclination. This study enables the researchers to provide a deeper understanding of Never Again by contending that the deep messages conveyed through the novel are the Nigerian civil war and the roles of women and children in our societies especially during war time. Keywords: Metafunctions, register variables, systemic functional linguistics, theme patterns

    Measurements of hydrogen cyanide (HCN) and acetylene (C2H2) from the Infrared Atmospheric Sounding Interferometer (IASI)

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    Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform InfraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values

    Cholesterol metabolism is a potential therapeutic target in Duchenne muscular dystrophy

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    Background: Duchenne muscular dystrophy (DMD) is a lethal muscle disease detected in approximately 1:5000 male births. DMD is caused by mutations in the DMD gene, encoding a critical protein that links the cytoskeleton and the extracellular matrix in skeletal and cardiac muscles. The primary consequence of the disrupted link between the extracellular matrix and the myofibre actin cytoskeleton is thought to involve sarcolemma destabilization, perturbation of Ca homeostasis, activation of proteases, mitochondrial damage, and tissue degeneration. A recently emphasized secondary aspect of the dystrophic process is a progressive metabolic change of the dystrophic tissue; however, the mechanism and nature of the metabolic dysregulation are yet poorly understood. In this study, we characterized a molecular mechanism of metabolic perturbation in DMD. Methods: We sequenced plasma miRNA in a DMD cohort, comprising 54 DMD patients treated or not by glucocorticoid, compared with 27 healthy controls, in three groups of the ages of 4–8, 8–12, and 12–20 years. We developed an original approach for the biological interpretation of miRNA dysregulation and produced a novel hypothesis concerning metabolic perturbation in DMD. We used the mdx mouse model for DMD for the investigation of this hypothesis. Results: We identified 96 dysregulated miRNAs (adjusted P-value <0.1), of which 74 were up-regulated and 22 were down-regulated in DMD. We confirmed the dysregulation in DMD of Dystro-miRs, Cardio-miRs, and a large number of the DLK1-DIO3 miRNAs. We also identified numerous dysregulated miRNAs yet unreported in DMD. Bioinformatics analysis of both target and host genes for dysregulated miRNAs predicted that lipid metabolism might be a critical metabolic perturbation in DMD. Investigation of skeletal muscles of the mdx mouse uncovered dysregulation of transcription factors of cholesterol and fatty acid metabolism (SREBP-1 and SREBP-2), perturbation of the mevalonate pathway, and the accumulation of cholesterol in the dystrophic muscles. Elevated cholesterol level was also found in muscle biopsies of DMD patients. Treatment of mdx mice with Simvastatin, a cholesterol-reducing agent, normalized these perturbations and partially restored the dystrophic parameters. Conclusions: This investigation supports that cholesterol metabolism and the mevalonate pathway are potential therapeutic targets in DMD. 2

    The Ordovician of France and neighbouring areas of Belgium and Germany

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    The Ordovician successions of France and neighbouring areas of Belgium and Germany are reviewed and correlated based on international chronostratigraphic and regional biostratigraphic charts. The same three megasequences related to the rift, drift and docking of Avalonia with Baltica can be tracked in Belgium and neighbouring areas (Brabant Massif and Ardenne inliers), western (Rhenish Massif) and northeastern Germany (Rügen). The remaining investigated areas were part of Gondwana in the Ordovician. The Armorican Massif shares with the Iberian Peninsula a Furongian–Early Ordovician gap (Toledanian or Norman gap), and a continuous Mid–Late Ordovician shelf sedimentation. The Occitan Domain (Montagne Noire and Mouthoumet massifs), eastern Pyrenees and northwestern Corsica share with southwestern Sardinia continuous shelf sedimentation in the Early Ordovician, and a Mid Ordovician ‘Sardic gap’. In the Ordovician, the Maures Massif probably belonged to the same Sardo-Occitan domain. The Vosges and Schwarzwald massifs display compa-rable, poorly preserved Ordovician successions, suggesting affinities with the Teplá-Barrandian and/or Molda-nubian zones of Central Europe.This paper is a contribution to the International Geoscience Programme (IGCP) projects 653 "The onset of the Great Ordovician Biodiversification Event" and 735 “Rocks and the Rise of Ordovician Life: Filling knowledge gaps in the Early Palaeozoic Biodiversification". The authors are particularly grateful to Annalisa Ferretti, David A.T. Harper and Petr Kraft for their careful and constructive reviews, comments and suggestions, which greatly improved the quality and relevance of the paper

    Combination disease-modifying treatment in spinal muscular atrophy: A proposed classification

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    We sought to devise a rational, systematic approach for defining/grouping survival motor neuron-targeted disease-modifying treatment (DMT) scenarios. The proposed classification is primarily based on a two-part differentiation: initial DMT, and persistence/discontinuation of subsequent DMT(s). Treatment categories were identified: monotherapy add-on, transient add-on, combination with onasemnogene abeparvovec, bridging to onasemnogene abeparvovec, and switching to onasemnogene abeparvovec. We validated this approach by applying the classification to the 443 patients currently in the RESTORE registry and explored the demographics of these different groups of patients. This work forms the basis to explore the safety and efficacy profile of the different combinations of DMT in SMA

    The emergence of international food safety standards and guidelines: understanding the current landscape through a historical approach

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    Following the Second World War, the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) teamed up to construct an International Codex Alimentarius (or 'food code') which emerged in 1963. The Codex Committee on Food Hygiene (CCFH) was charged with the task of developing microbial hygiene standards, although it found itself embroiled in debate with the WHO over the nature these standards should take. The WHO was increasingly relying upon the input of biometricians and especially the International Commission on Microbial Specifications for Foods (ICMSF) which had developed statistical sampling plans for determining the microbial counts in the final end products. The CCFH, however, was initially more focused on a qualitative approach which looked at the entire food production system and developed codes of practice as well as more descriptive end-product specifications which the WHO argued were 'not scientifically correct'. Drawing upon historical archival material (correspondence and reports) from the WHO and FAO, this article examines this debate over microbial hygiene standards and suggests that there are many lessons from history which could shed light upon current debates and efforts in international food safety management systems and approaches
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