Evaluating portable air cleaner effectiveness in residential settings to reduce exposures to biomass smoke resulting from prescribed burns

AIM: Prescribed burning is the most common method employed to reduce fuel loads in flammable landscapes. This practice is designed to reduce the hazard associated with uncontrolled bushfires. Prescribed burns are frequently conducted close to residential areas, and the associated smoke impacts can adversely affect community health. Particulate matter is the predominant pollutant within the smoke and is strongly and consistently linked with adverse health effects. Outdoor smoke readily infiltrates buildings and reduces the quality of indoor air. Portable air cleaners containing high-efficiency particulate air (HEPA) filters are a promising indoor air quality intervention for reducing outdoor smoke exposure.METHODS: We provided 10 homes from semirural regions of Victoria, Australia, with HEPA cleaners and conducted continuous monitoring of indoor and outdoor fine particulate matter (PM2.5) for 2-4 weeks during prescribed burning periods. We calculated the potential improvements to indoor air quality when operating a HEPA cleaner during a smoke episode. Ventilation measures were conducted to identify points of smoke ingress and housing characteristics that could lead to higher infiltration rates.RESULTS: Depending on the house, the use of HEPA cleaners resulted in a reduction in indoor PM2.5 concentrations of 30-74%.CONCLUSIONS: HEPA cleaners have the potential to substantially improve indoor air quality during episodic smoke episodes.</p

Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC pp collision data at root s=7 and 8 TeV

70 pages plus author lists + cover page (104 pages total), 32 figures, 22 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-07/ and at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIG-15-002/Combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes, namely gluon fusion, vector boson fusion, and associated production with a $W$ or a $Z$ boson or a pair of top quarks, and of the six decay modes $H \to ZZ, WW$, $\gamma\gamma, \tau\tau, bb$, and $\mu\mu$. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined measurement by the ATLAS and CMS experiments. The analysis uses the CERN LHC proton--proton collision data recorded by the ATLAS and CMS experiments in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and 20 fb$^{-1}$ at $\sqrt{s} = 8$ TeV. The Higgs boson production and decay rates measured by the two experiments are combined within the context of three generic parameterisations: two based on cross sections and branching fractions, and one on ratios of coupling modifiers. Several interpretations of the measurements with more model-dependent parameterisations are also given. The combined signal yield relative to the Standard Model prediction is measured to be 1.09 $\pm$ 0.11. The combined measurements lead to observed significances for the vector boson fusion production process and for the $H \to \tau\tau$ decay of $5.4$ and $5.5$ standard deviations, respectively. The data are consistent with the Standard Model predictions for all parameterisations considered.Peer reviewe

Aptitude de Salmonella à contaminer l'oeuf coquille et élaboration d'un revêtement antibactérien

Salmonella enterica est une des espèces bactériennes les plus impliquées dans les toxi-infections alimentaires collectives (Tiac). Cette bactérie ubiquitaire, provoquant des gastroentérites, est capable de contaminer un large panel d aliments. Cependant, l apparition de Tiac est majoritairement provoquée par la consommation de volaille et d œufs. Dans ce contexte, l objectif de ce travail a été premièrement de caractériser quatre souches bactériennes du genre Salmonella, trois sérovar Enteritidis et un sérovar Typhimurium, et d évaluer leur aptitude à pénétrer dans l œuf coquille par contamination horizontale. Dans un second temps, l objectif s est porté sur la réalisation d un film alimentaire aux propriétés antibactériennes. Au cours de la caractérisation des quatre souches de Salmonella, leur morphologie et leur croissance à différentes températures ont été observées. La persistance de Salmonella dans l environnement a ensuite été analysée par l étude du morphotype rdar et l aptitude des quatre souches à former des biofilms. Des tests de mobilité bactérienne, swimming , twitching et swarming , ont également été effectués, ainsi que l extraction et la caractérisation des lipopolysaccharides. Enfin, l étude de la pénétration de ces quatre souches a été réalisée par la méthode agar-moulding afin de corréler les différents comportements et facteurs évoqués précédemment avec l aptitude de Salmonella à contaminer et à pénétrer dans l œuf coquille. La deuxième partie de ce travail concerne la réalisation d un film alimentaire aux propriétés antibactériennes vis-à-vis de Salmonella Enteritidis. Parmi trois biopolymères, le chitosan a été sélectionné et a été réticulé avec du tripolyphosphate pour améliorer sa stabilité. Une attention particulière s est ensuite portée sur l activité antibactérienne de la photocatalyse du dioxyde de titane afin d incorporer ce dernier au film de chitosan. Finalement, le film de chitosan seul, a été appliqué sur une population d œufs, qui a ensuite été contaminée dans le but d évaluer l impact du film sur la pénétration de Salmonella Enteritidis dans l œuf coquille.Salmonella enterica is one of the most common species responsible for foodborne disease throughout the world. This ubiquitous bacteria, inducing gastroenteritis, can contaminate a wide range of foods. Foodborne gastroenteritis is usually due to the consumption of poultry and eggs. In this context, the aim of this work was, first, to characterize four Salmonella strains and to evaluate the ability of the strains to penetrate eggs through the eggshell and secondly, to develop an antibacterial food coating. Salmonella characterization consists in studying bacterial morphology and growth at several temperatures. Next, Salmonella persistence in environment was evaluated by studying the rdar morphotype and the biofilm formation using confocal laser scanning microscopy. Bacterial motility was also observed: swimming , swarming , and twitching tests were performed. Finally, lipopolysaccharides were extracted and characterized by SDS-PAGE electrophoresis. All these experiments were carried out on four Salmonella enterica strains to determine if these behaviours and factors influenced the penetration of Salmonella in the egg content through the eggshell. Thus in conclusion, the ability of the four strains to penetrate through the eggshell was studied performing the agar-moulding method. The second part of the work related the elaboration of a food coating providing an antibacterial activity against Salmonella Enteritidis. Among three biopolymers, chitosan was chosen and was reticulated with tripolyphosphate to increase it stability. The antibacterial activity of the photocatalysis of titanium dioxide was also studied. The aim was to add titanium dioxide in the chitosan coating. It was then applied on eggs which were then contaminated with Salmonella Enteritidis to evaluate the impact of the chitosan coating on bacterial penetration in egg content.LORIENT-BU (561212106) / SudocSudocFranceF

Conception de peintures biodégradables, non toxiques, et facilitant l'élimination des salissures marines

LORIENT-BU (561212106) / SudocSudocFranceF

Conception de peintures biodégradables, non toxiques, et facilitant l'élimination des salissures marines

LORIENT-BU (561212106) / SudocSudocFranceF

Effect of biocidal coatings on microfouling In vitro and in situ results

Coatings containing booster biocide (diuron and tolylfluanid) and copper thiocyanate were exposed to marine bacteria and diatoms. The effect of biocides included in coatings on cells adhesion and biofilm formation was studied in different conditions of immersion. In vitro, two marine bacterial strains (Pseudoalteromonas sp. and Bacillus sp.) and two diatom strains (Cytlndrotheca closterium and Amphora sp.) were used in mono-species culture. In situ (French Atlantic Ocean, Lorient Harbour), the colonization process of natural microfouling onto coatings were evaluated. Confocal laser scanning microscopy was used to observe and quantify cells adhesion on the coatings. The results demonstrated that biocidal coatings are more active against diatom attachment (inhibition) than against bacterial adhesion (no effect). Microalgae were more sensitive to coating. The results between in vitro and in situ assays showed a difference in behaviour according to the mode of presentation of biocide (biocidal solution or coating) or the environment (mono-species culture or marine consortium)

Monitoring de la croissance de bactéries / biofilms bactériens via une sonde coaxiale

International audienceLe but de ce travail est de développer une sonde radiofréquence pour le suivi du développement de bactéries et/ou de biofilm bactérien. Il s'agit d'une sonde coaxiale ouverte plongée dans un réservoir rempli d'une solution. Des simulations HFSS ont été effectuées afin de vérifier la faisabilité de la sonde. Le suivi de la prolifération de deux bactéries modèles a été testé avec succès. La détermination de la présence d'un biofilm est aussi possible. Ces suivis peuvent être obtenus à une fréquence unique permettant un suivi temps réel à faible coût

Metal resistance genes enrichment in marine biofilm communities selected by biocide-containing surfaces in temperate and tropical coastal environments

International audienceMicroorganisms able to form biofilms in marine ecosystems are selected depending on immersed surfaces and environmental conditions. Cell attachment directly on toxic surfaces like antifouling coatings suggests a selection of tolerant (or resistant) organisms with characteristics conferring adaptive advantages. We investigated if environment would drive metal resistance gene abundance in biofilms on artificial surfaces. Biofilms were sampled from three surfaces (a PVC reference and two antifouling coatings) deployed in three coastal waters with dissimilar characteristics: The Mediterranean Sea (Toulon) and Atlantic (Lorient) and Indian (Reunion) Oceans. The two coatings differed in metals composition, either Cu thiocyanate and Zn pyrithione (A3) or Cu2O (Hy). Metal resistance genes (MRG) specific to copper (cusA, copA, cueO) or other metals (czcA and pbrT) were monitored with qPCR in parallel to the microbial community using 16S rRNA gene metabarcoding. A lower α-diversity on A3 or Hy than on PVC was observed independent on the site. Weighted Unifrac suggested segregation of communities primarily by surface, with lower site effect. Metacoder log2 fold change ratio and LeFSe discrimination suggested Marinobacter to be specific of Hy and Altererythrobacter, Erythrobacter and Sphingorhabdus of A3. Likewise, the relative abundance of MRG (MRG/bacterial 16S rRNA) varied between surfaces and sites. A3 presented the greatest relative abundances for cusA, cueO and czcA. The latter could only be amplified from A3 communities, except at Toulon. Hy surface presented the highest relative abundance for copA, specifically at Lorient. These relative abundances were correlated with LeFSe discriminant taxa. Dasania correlated positively with all MRG except cueO. Marinobacter found in greater abundance in Hy biofilm communities correlated with the highest abundances of copA and Roseovarius with czcA. These results prove the selection of specific communities with abilities to tolerate metallic biocides forming biofilms over antifouling surfaces, and the secondary but significant influence of local environmental factors