Effects of urban coarse particles inhalation on oxidative and inflammatory parameters in the mouse lung and colon

Background

Air pollution is a recognized aggravating factor for pulmonary diseases and has notably deleterious effects on asthma, bronchitis and pneumonia. Recent studies suggest that air pollution may also cause adverse effects in the gastrointestinal tract. Accumulating experimental evidence shows that immune responses in the pulmonary and intestinal mucosae are closely interrelated, and that gut-lung crosstalk controls pathophysiological processes such as responses to cigarette smoke and influenza virus infection. Our first aim was to collect urban coarse particulate matter (PM) and to characterize them for elemental content, gastric bioaccessibility, and oxidative potential; our second aim was to determine the short-term effects of urban coarse PM inhalation on pulmonary and colonic mucosae in mice, and to test the hypothesis that the well-known antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of PM inhalation.

Results

The collected PM had classical features of urban particles and possessed oxidative potential partly attributable to their metal fraction. Bioaccessibility study confirmed the high solubility of some metals at the gastric level. Male mice were exposed to urban coarse PM in a ventilated inhalation chamber for 15 days at a concentration relevant to episodic elevation peak of air pollution. Coarse PM inhalation induced systemic oxidative stress, recruited immune cells to the lung, and increased cytokine levels in the lung and colon. Concomitant oral administration of NAC reversed all the observed effects relative to the inhalation of coarse PM.

Conclusions

Coarse PM-induced low-grade inflammation in the lung and colon is mediated by oxidative stress and deserves more investigation as potentiating factor for inflammatory diseases.

     

Metal transfer to plants grown on a dredged sediment: use of radioactive isotope 203Hg and titanium

Improperly disposed of dredged sediments contaminated with metals may induce long-term leaching and an increase of metal concentrations in ground waters and vegetal cover plants. The objective of the study was to quantify the sediment-to-plant transfer of Cu, Pb, Hg and Zn with a particular focus on the pathway of Hg and to determine whether the establishment of vegetal cover modifies the metal availability. A pot experiment with rape (Brassica napus), cabbage (Brassica oleraccea) and red fescue (Festuca rubra) was set up using a sediment first spiked with the radioisotope 203Hg. Zinc concentrations (197-543 mg kg(-1) DM) in leaves were higher than Cu concentration (197-543 mg kg(-1) DM), Pb concentration (2.3-2.6 mg kg(-1) DM) and Hg concentration (0.9-1.7 mg kg(-1) DM). Leaves-to-sediment ratios decreased as follows: Zn > Cu > Hg > Pb. According to Ti measurements, metal contamination by dry deposition was less than 1%. Mercury concentration in plant leaves was higher than European and French thresholds. Foliar absorption of volatile Hg was a major pathway for Hg contamination with a root absorption of Hg higher in rape than in cabbage and red fescue. Growth of each species increased Cu solubility. Zinc solubility was increased only in the presence of rape. The highest increase of Cu solubility was observed for red fescue whereas this species largely decreased Zn solubility. Dissolved organic carbon (DOC) measurements suggested that Cu solubilisation could result from organic matter or release of natural plant exudates. Dissolved inorganic carbon (DIC) measures suggested that the high Zn solubility in the presence of rape could originate from a generation of acidity in rape rhizosphere and a subsequent dissolution of calcium carbonates. Consequently, emission of volatile Hg from contaminated dredged sediments and also the potential increase of metal solubility by a vegetal cover of grass when used in phytostabilisation must be taken into account by decision makers.     

Experimental and numerical study of heavy gas dispersion in a ventilated room

In order to better evaluate the consequences of an accidental release of heavy gas, such as uranium hexafluoride (UF(6)), in some installations in the nuclear fuel cycle, an experimental and numerical study was conducted by IRSN on heavy gas dispersion in a ventilated room. This study was based on about 20 injection configurations of a large quantity of a heavy tracer gas, sulphur hexafluoride (SF(6)), inside two ventilated rooms of different sizes. Stratification of the tracer gas was detected in all the configurations studied, even at low concentrations. Numerical simulations performed with the multidimensional CFX code enabled the stratification and the concentration levels reached in the rooms to be predicted overall, and the higher the air flow rate, the more satisfactory the comparison between simulation and experiment.     

Inverse-problem approach for particle digital holography: accurate location based on local optimization

We propose a microparticle localization scheme in digital holography. Most conventional digital holography methods are based on Fresnel transform and present several problems such as twin-image noise, border effects, and other effects. To avoid these difficulties, we propose an inverse-problem approach, which yields the optimal particle set that best models the observed hologram image. We resolve this global optimization problem by conventional particle detection followed by a local refinement for each particle. Results for both simulated and real digital holograms show strong improvement in the localization of the particles, particularly along the depth dimension. In our simulations, the position precision is > or =1 microm rms. Our results also show that the localization precision does not deteriorate for particles near the edge of the field of view.     

Promoting energy-saving behaviour: formal social groups as promising middle actors for municipal interventions

City governments worldwide are trying to motivate their citizens to reduce their energy use—a particular challenge as they try to reach individual households. A promising strategy to engage the public broadly entails collaborating with middle actors to multiply the effects of municipal interventions. Some of these middle actors are formal social groups (e.g. sports clubs and neighbourhood associations). We conducted an online experiment (N = 136) to determine whether such interventions were more effective when they are communicated through formal social groups than when communicated through city governments. Participants received letters containing advice for saving energy in the household. Willingness to participate was higher when the letters came from formal social groups than when they came from a city agency. Furthermore, actual members of formal social groups generally were more willing to participate. Our evidence suggests that formal social groups are promising middle actors for energy conservation campaigns and that city governments should engage more often with these groups to communicate with residents.     

The Study of a 231 French Patient Cohort Significantly Extends the Mutational Spectrum of the Two Major Usher Genes MYO7A and USH2A

Usher syndrome is an autosomal recessive disorder characterized by congenital hearing loss combined with retinitis pigmentosa, and in some cases, vestibular areflexia. Three clinical subtypes are distinguished, and MYO7A and USH2A represent the two major causal genes involved in Usher type I, the most severe form, and type II, the most frequent form, respectively. Massively parallel sequencing was performed on a cohort of patients in the context of a molecular diagnosis to confirm clinical suspicion of Usher syndrome. We report here 231 pathogenic MYO7A and USH2A genotypes identified in 73 Usher type I and 158 Usher type II patients. Furthermore, we present the ACMG classification of the variants, which comprise all types. Among them, 68 have not been previously reported in the literature, including 12 missense and 16 splice variants. We also report a new deep intronic variant in USH2A. Despite the important number of molecular studies published on these two genes, we show that during the course of routine genetic diagnosis, undescribed variants continue to be identified at a high rate. This is particularly pertinent in the current era, where therapeutic strategies based on DNA or RNA technologies are being developed.     

Engineering of an MBR supernatant fouling layer by fine particles addition: a possible way to control cake compressibility

For membrane bioreactors (MBR) applied to wastewater treatment membrane fouling is still the prevalent issue. The main limiting phenomena related to fouling is a sudden jump of the transmembrane pressure (TMP) often attributed to the collapse of the fouling layer. Among existing techniques to avoid or to delay this collapse, the addition of active particles membrane fouling reducers (polymer, resins, powdered activated carbon (PAC), zeolithe…) showed promising results.Thus the main objective of this work is to determine if fouling can be reduced by inclusion of inert particles (500 nm and inert compared to other fouling reducers) and which is the impact on filtration performances of the structuring of the fouling. Those particles were chosen for their different surface properties and their capability to form well structured layer.Results, obtained at constant pressure in dead end mode, show that the presence of particles changes foulant deposition and induces non-compressible fouling (in the range of 0.5-1 bar) and higher rejection values compared to filtration done on supernatant alone. Indeed dead end filtration tests show that whatever interactions between biofluid and particles, the addition of particles leads to better filtration performances (in terms of rejection, and fouling layer compressibility). Moreover results confirm the important role played by macromolecular compounds, during supernatant filtration, creating highly compressible and reversible fouling.In conclusion, this study done at lab-scale suggests the potential benefit to engineer fouling structure to control or to delay the collapse of the fouling layer. Finally this study offers the opportunities to enlarge the choice of membrane fouling reducers by taking into consideration their ability to form more consistent fouling (i.e. rigid, structured fouling).     

Performance-friendly rule extraction in large water data-sets with AOC posets and relational concept analysis

In this paper, we consider data analysis methods for knowledge extraction from large water data-sets. More specifically, we try to connect physico-chemical parameters and the characteristics of taxons living in sample sites. Among these data analysis methods, we consider formal concept analysis (FCA), which is a recognized tool for classification and rule discovery on object–attribute data. Relational concept analysis (RCA) relies on FCA and deals with sets of object–attribute data provided with relations. RCA produces more informative results but at the expense of an increase in complexity. Besides, in numerous applications of FCA, the partially ordered set of concepts introducing attributes or objects (AOC poset, for Attribute–Object–Concept poset) is used rather than the concept lattice in order to reduce combinatorial problems. AOC posets are much smaller and easier to compute than concept lattices and still contain the information needed to rebuild the initial data. This paper introduces a variant of the RCA process based on AOC posets rather than concept lattices. This approach is compared with RCA based on iceberg lattices. Experiments are performed with various scaling operators, and a specific operator is introduced to deal with noisy data. We show that using AOC poset on water data-sets provides a reasonable concept number and allows us to extract meaningful implication rules (association rules whose confidence is 1), whose semantics depends on the chosen scaling operator.     

Bacterial formation of tooeleite and mixed arsenic(III) or arsenic(V)-iron(III) gels in the Carnoulès acid mine drainage,France. A XANES,XRD, and SEM study

The oxidation of Fe(II) in acid mine drainage (AMD) leads to the precipitation of Fe(III) compounds which may incorporate toxic elements, such as arsenic (As), within their structure or adsorb them at their surface, thus limiting their mobility. The present work provides evidence for spatial and seasonal variations of microbial activity that influence arsenite oxidation and As immobilization in the heavily contaminated AMD from the Carnoulès mine, Gard, France ([As III] = 80 to 280 mg x L(-1) in the acidic spring draining the waste-pile). In the first tens of meters of the AMD, the rapid oxidation of Fe(II) leads to the coprecipitation of large amounts of As with Fe(III) in bacterial mats. XRD, XANES, and SEM analyses of sediments and stromatolite samples revealed the unusual formation of As(III)-rich compounds, especially nanocrystalline tooeleite, Fe6(AsO3)4(SO4)(OH)4 x 4H2O, a rare ferric arsenite sulfate oxy-hydroxide mineral, together with XRD-amorphous mixed As(III)/As(V)-Fe(III) oxy-hydroxide compounds. In the wet season, the suspended sediments of the upstream zone essentially consist of tooeleite associated with am-As(III)-Fe(III) oxy-hydroxides, while am-As(V)-Fe(III) oxy-hydroxides, having As:Fe molar ratios as high as 0.6-0.8, dominate in the dry season. Comparing natural and bioassay samples revealed that the formation of As(III)-rich compounds in the wet season may be related to the metabolic activity of bacterial strains able to oxidize Fe(II) but not As(III). One of these strains, having an Acidithiobacillus ferrooxidans genotype, has been isolated from the Carnoulès AMD. In contrast, the formation of As(V)-rich compounds in the dry season can be related to both biotic and abiotic oxidation of As(III) to As(V). Some Thiomonas strains isolated from the Carnoulès AMD were shown to be able to catalyze the oxidation of As(III) to As(V) in solution. Therefore, they can promote the formation of mixed As(V)-Fe(III) oxy-hydroxides, provided enough Fe(II) oxidizes. These results yield a better understanding of natural processes at this site and may help in designing efficient As-removal processes.