Removal of dimethylsulfide, n-hexane and toluene from waste air in a flat membrane bioreactor under continuous conditions

Dimethylsulfide (DMS), n-hexane and toluene removal from a waste air was carried out by using a flat composite membrane bioreactor under continuous feeding conditions. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 1.5 μm supported with a porous polyacrylonitrile layer of 50 μm. The membrane bioreactor (MBR) was operated during 9 months in which several operational conditions were applied. The inlet load of each compound ranged from 0 to 350 g m-3 h-1 and removal efficiencies of 80, 70 and 0 to 30 % were reached for DMS, toluene and hexane respectively. Two different empty bed residence time (EBRT) were applied on the MBR in order to check the influence of the residence time on the reactor performance. In this case, DMS and toluene removal increased with an increasing EBRT, while the removal of hexane remained constant. By increasing the flow rate of the recirculated liquid from 22 l min-1 to 45 l min-1, the total performance of the biofilter decreased. To increase the mass transfer of hexane in order to get a higher removal, an emulsion of water/silicone oil 80/20 V% was used as recirculated medium at the liquid side of the reactor. This caused a decrease in DMS removal while the removal of toluene remained constant. The variation on the hexane removal decreased significantly, so the reactor became more reliable for degrading hexane

Modelling complex livestock-agricultural systems at a regional scale : A case study in La Reunion

Réunion Island, situated in the Indian Ocean, presents a unique case study to model regional bio-economic parameters of the dairy industry. It is a good example of a closed system for movement of animals, available labour, consumption of products, and available land. The present study models the dairy sector at a regional (island) level, in close collaboration with key stakeholders, to study the impact of new agricultural policies in terms of changes to subsidy norms, price fluctuations and environment, with reference to nitrogen excess. The model can be used to generate a number of scenarios, to explore the effects of various industry controls, such as fixing the stocking rate according to EU norms, increasing or reducing the milk subsidy, intensification (such as an increase in milk production to 40 million litres per year) and labour and price constraints (such as an increase or reduction in the milk price or a reduction in labour hours). The model is being consulted by the local dairy cooperative as a discussion support tool at a regional scale to look at implications of expanding the sector and its economic, environmental and social impact. (Résumé d'auteur

Intratympanic steroids as a salvage therapy for severe to profound idiopathic sudden sensorineural hearing loss

Background: Idiopathic sudden sensorineural hearing loss (ISSNHL) is defined as a decline in hearing affecting three or more frequencies by 30 dB Objective: The aim of this study was to evaluate the results of intratympanic steroids as a salvage treatment for severe ISSNHL. Materials and methods: A regimen of three IT steroid injections was offered to patients who failed a 7-days intravenous steroid treatment. Eighty-four patients underwent IT salvage treatment (IT group). Their outcomes were compared with those of 255 patients with severe ISSNHL who received the same intravenous steroid regimen without salvage IT steroid therapy (Control group). Results: 56% of the patients in the IT group had a hearing improvement of >15 dB after one month. The average hearing improvements were 26.5 ± 28 dB and 27.9 ± 24 dB in the IT group and the Control group, respectively (p ¼ .67). However, patients with a type E audiogram pattern (total deafness), displayed a substantial hearing gain. Conclusion: Intratympanic steroids failed to show a global auditory benefit as a salvage treatment in patients with severe ISSNHL. Significance: Our data suggest that a salvage treatment with intratympanic dexamethasone may be offered to patients with total deafness for whom the first systemic treatment has failed

Integrated DNA walking system to characterize a broad spectrum of GMOs in food/feed matrices

Background: In order to provide a system fully integrated with qPCR screening, usually used in GMO routine analysis, as well as being able to detect, characterize and identify a broad spectrum of GMOs in food/feed matrices, two bidirectional DNA walking methods targeting p35S or tNOS, the most common transgenic elements found in GM crops, were developed. These newly developed DNA walking methods are completing the previously implemented DNA walking method targeting the t35S pCAMBIA element. Results: First, the newly developed DNA walking methods, anchored on the sequences used for the p35S or tNOS qPCR screening, were tested on Bt rice that contains these two transgenic elements. Second, the methods were assessed on a maize sample containing a low amount of the GM MON863 event, representing a more complex matrix in terms of genome size and sensitivity. Finally, to illustrate its applicability in GMO routine analysis by enforcement laboratories, the entire workflow of the integrated strategy, including qPCR screening to detect the potential presence of GMOs and the subsequent DNA walking methods to characterize and identify the detected GMOs, was applied on a GeMMA Scheme Proficiency Test matrix. Via the characterization of the transgene flanking region between the transgenic cassette and the plant genome as well as of a part of the transgenic cassette, the presence of GMOs was properly confirmed or infirmed in all tested samples. Conclusion: Due to their simple procedure and their short time-frame to get results, the developed DNA walking methods proposed here can be easily implemented in GMO routine analysis by the enforcement laboratories. In providing crucial information about the transgene flanking regions and/or the transgenic cassettes, this DNA walking strategy is a key molecular tool to prove the presence of GMOs in any given food/feed matrix