Évaluation de la validité des modèles de risque pour prédire l’incidence des gastroentérites d’origine hydrique au Québec

Les analyses de risque microbiologique, dont l'ÉQRM (évaluation quantitative du risque microbien) proposent de nouvelles techniques pour évaluer les conséquences sanitaires liées à la contamination microbiologique de l'eau potable. Ces modèles intègrent les données physico-chimiques et microbiologiques des usines de traitement d'eau pour quantifier un risque à la santé. Le projet visait à évaluer le lien entre le risque estimé selon un modèle ÉQRM et l’incidence de giardiase observée. Les banques de données des maladies à déclaration obligatoire et d’INFO-SANTÉ ont été utilisées pour comparer le résultat de l’analyse de risque à celui des analyses épidémiologiques. Les municipalités considérées les plus à risque par l'ÉQRM ont une incidence de gastroentérite et de parasitoses plus élevée. Cependant, l'ampleur du risque prédit ne correspond pas à celui observé. Il est souhaitable que les modèles d’ÉQRM incorporent des données populationnelles pour prédire avec une plus grande exactitude le risque épidémiologique

The leading thread: video, media, installation: a conversation with Federica Marangoni.

Federica Marangoni is an important Italian media artist and designer based in Venice. She is a pioneer of video, performance and installation in Italy. Marangoni's exhibition "Il filo conduttore = The leading thread" (2015, held at Ca'Pesaro International Gallery of Modern Art, Venice), was curated by Gabriella Belli. The exhibition was organised by the Fondazione Musei Civici di Venezia in response to the Venice Biennale's 56th International Art Exhibition "All The World's Futures". The following interview consists of several conversations held before and after this major exhibition, and forms part of the AHRC-funded research project "EWVA European Women's Video Art in the 70s and 80s", based at the Duncan of Jordanstone College of Art and Design, University of Dundee

Decoding the biosynthesis of hydrocarbons in ants

Dissertação de mestrado em Biologia Celular e Molecular apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de CoimbraHá cerca de vinte anos pensava-se que a tuberculose era uma doença em vias de erradicação no entanto, hoje em dia, é uma das doenças mais mortíferas do mundo. A Organização Mundial de Saúde estima que mais de um terço da população mundial esteja infectada com tuberculose. A maltocinase (Mak) é uma enzima essencial para o crescimento micobacteriano que se encontra presente na maioria dos genomas micobacterianos anotados. Contudo, o papel fisiológico desta enzima ainda não é totalmente conhecido. Numa tentativa de elucidar o papel desempenhado pela Mak na fisiologia micobacteriana foram, neste trabalho, exploradas funções adicionais da proteína, in vitro. Foram testados substratos alternativos (aceitadores de grupo fosforil), bem como a possibilidade de a enzima estar envolvida na inactivação de antibióticos aminoglicosídeos. Foi ainda realizado um ensaio preliminar para análise das respostas transcripcionais do gene correspondente em M. smegmatis, em diferentes condições nutricionais. Simultaneamente, para confirmar o papel essencial proposto para a Mak, o organismo M. marinum foi seleccionado, como ferramenta para construção de um mutante knock-out condicional para mak, para deste modo avaliar os efeitos do silenciamento do gene no fenótipo do mutante. A proteína recombinante, com cauda de histidinas, foi purificada com vista a serem efectuados testes de especificidade de substratos. O protocolo de purificação foi modificado, através da alteração do pH do tampão fosfato de sódio, de modo a encurtar a duração da purificação. Em seguida, vários substratos foram testados comoaceitadores de grupos fosforil, nomeadamente antibióticos aminoglicosídeos, dissacarídeos e trissacarídeos. No entanto, não foi detectada qualquer actividade, excepto para a maltose, o que implica que em M. smegmatis o papel de aceitador de grupos fosfatos deve ser específico para este açúcar. É pois extremamente improvável que a proteína Mak confira resistência a aminoglicosídeos. Para avaliar a relação entre a expressão do gene mak de M. smegmatis e diferentes fontes de carbono no meio de cultura, determinámos a actividade da enzima em extractos celulares de M. smegmatis. Os resultados indicam que a actividade da Mak é significativamente afectada pela presença de maltose no meio. Com o objectivo de analisar as respostas trascripcionais do gene mak em diferentes condições nutricionais uma experiência de RT-PCR foi optimizada. No entanto, devido a uma série de problemas de ordem técnica e limitações a nível temporal, não foi possível progredir para além do que é apresentado neste trabalho. O desenho e construção para a criação do mutante condicional para a mak apresentado neste trabalho vão permitir, futuramente, a expressão condicional de genes essenciais ao crescimento micobacteriano, permitindo deste modo um melhor entendimento do seu envolvimento no metabolismo destas bactérias.Twenty years ago Human tuberculosis (TB) was thought to be a disease on the verge of eradication. Nowadays TB is one of the deadliest diseases in the world and the WHO estimates that more than one-third of the world’s population is infected with TB. Maltokinase (Mak) is an enzyme essential for mycobacterial growth that is present in nearly all mycobacterial genomes. Nonetheless the physiological role of this enzyme remains to be fully elucidated. In an effort towards unveiling the role of Mak in mycobacterial physiology additional functions of the enzyme in vitro were explored, namely by testing possible alternative substrates (phosphoryl acceptors) as well as the possibility of the involvement of this enzyme in the inactivation of aminoglycoside antibiotics. A preliminary analysis of the transcriptional responses of the corresponding gene in M. smegmatis, in different nutritional conditions, was attempted. Concurrently, to confirm the proposed essentiality of Mak, M. marinum was selected as the tool for the construction of a mak conditional knock-out mutant, and thus, evaluate the effects of silencing the gene on the mutant’s phenotype. Recombinant His-tagged Mak was purified to further test substrate specificity. The purification protocol was made less laborious by the modification of the sodium phosphate buffer pH. Subsequently several substrates were tested as phosphoryl group acceptors Namely aminoglycoside antibiotics, disaccharides and trisaccharides, however no activity was detected, except for maltose, implicating that in M. smegmatisthe role of phosphate acceptor might be specific to maltose. It is then extremely unlikely the protein could render aminoglycoside resistance to bacteria. To evaluate the relation between mak expression and the nutritional source in the growth medium the activity of the enzyme was determined in M. smegmatis cell-free extracts. The results indicate that Mak activity is significantly affected by the presence of maltose in the medium. In order to analyze the transcriptional responses of the mak gene in different nutritional conditions an RT-PCR experiment was optimized but due to technical problems and time constraints, no further progress could be made beyond this stage. The design and construction for the engineering of the mak conditional mutant done in this work will, in the future, allow the conditional expression of genes essential for mycobacterial growth and in doing so, provide a better understanding of their involvement in mycobacterial metabolism

Mask-based dual-axes tomoholography using soft x-rays

We explore tomographic mask-based Fourier transform x-ray holography with respect to the use of a thin slit as a reference wave source. This imaging technique exclusively uses the interference between the waves scattered by the object and the slit simplifying the experimental realization and ensuring high data quality. Furthermore, we introduce a second reference slit to rotate the sample around a second axis and to record a dual-axes tomogram. Compared to a single-axis tomogram, the reconstruction artifacts are decreased in accordance with the reduced missing data wedge. Two demonstration experiments are performed where test structures are imaged with a lateral resolution below 100 nm

Body, Sign and Double: a Parallel Analysis of Elaine Shemilt’s Doppelganger, Federica Marangoni’s The Box of Life and Sanja Ivekovic ́’s Instructions N°1 and Make up - Make down

Body, identity, self-representation, sexuality, stereotypical images of women portrayed by the society and the media, and the condition of female professional artists: these themes were expressed and developed in several early video works in the 70s and early 80s by women artists that didn’t have direct knowledge or contact between each other. This simultaneity of thematic is an unusual phenomenon that reveals common, contemporary sensibilities within both Europe and the USA

Cuticular Hydrocarbon Analysis in Forensic Entomology: A Review

Blowflies are the first inhabitants of decomposing remains and are therefore of forensic relevance for post mortem interval estimations. Forensic entomology is becoming widely accepted as a branch of forensic science and is being utilised more within forensic casework. This wider use has driven an increase in research being carried out within the field, in particular, in less “classical” techniques such as DNA and chemical analysis in the form of cuticular hydrocarbon analysis. This short review will examine the research currently being studied in the area of cuticular hydrocarbon analysis of forensically important Diptera for species identification and ageing

Potential mechanisms for the effects of far-infrared on the cardiovascular system:a review

Far-infrared (FIR) is a form of thermal radiation, which may have beneficial effects on cardiovascular health. Clinical studies suggest that FIR irradiation may have therapeutic effects in heart failure, myocardial ischaemia and may improve flow and survival of arteriovenous fistula. Animal studies have suggested a wide range of potential mechanisms involving endothelial nitric oxide synthase and nitric oxide bioavailability, oxidative stress, heat shock proteins and endothelial precursor cells. However, the exact cellular and molecular mechanism of FIR on the cardiovascular system remains elusive. The purpose of this review is to discuss the current literature, focusing on mechanistic studies involving the cardiovascular system, and with a view to highlighting areas for future investigation.<br/

Use of cost-effectiveness analysis to compare the efficiency of study identification methods in systematic reviews

BACKGROUND: Meta-research studies investigating methods, systems, and processes designed to improve the efficiency of systematic review workflows can contribute to building an evidence base that can help to increase value and reduce waste in research. This study demonstrates the use of an economic evaluation framework to compare the costs and effects of four variant approaches to identifying eligible studies for consideration in systematic reviews. METHODS: A cost-effectiveness analysis was conducted using a basic decision-analytic model, to compare the relative efficiency of 'safety first', 'double screening', 'single screening' and 'single screening with text mining' approaches in the title-abstract screening stage of a 'case study' systematic review about undergraduate medical education in UK general practice settings. Incremental cost-effectiveness ratios (ICERs) were calculated as the 'incremental cost per citation 'saved' from inappropriate exclusion' from the review. Resource use and effect parameters were estimated based on retrospective analysis of 'review process' meta-data curated alongside the 'case study' review, in conjunction with retrospective simulation studies to model the integrated use of text mining. Unit cost parameters were estimated based on the 'case study' review's project budget. A base case analysis was conducted, with deterministic sensitivity analyses to investigate the impact of variations in values of key parameters. RESULTS: Use of 'single screening with text mining' would have resulted in title-abstract screening workload reductions (base case analysis) of >60 % compared with other approaches. Across modelled scenarios, the 'safety first' approach was, consistently, equally effective and less costly than conventional 'double screening'. Compared with 'single screening with text mining', estimated ICERs for the two non-dominated approaches (base case analyses) ranged from £1975 ('single screening' without a 'provisionally included' code) to £4427 ('safety first' with a 'provisionally included' code) per citation 'saved'. Patterns of results were consistent between base case and sensitivity analyses. CONCLUSIONS: Alternatives to the conventional 'double screening' approach, integrating text mining, warrant further consideration as potentially more efficient approaches to identifying eligible studies for systematic reviews. Comparable economic evaluations conducted using other systematic review datasets are needed to determine the generalisability of these findings and to build an evidence base to inform guidance for review authors