Experimental Infection of Captive Red Foxes (Vulpes vulpes) with Mycobacterium bovis

[EN] In Europe, animal tuberculosis (TB) due to Mycobacterium bovis involves multi-host communities that include cattle and wildlife species, such as wild boar (Sus scrofa), badgers (Meles meles) and red deer (Cervus elaphus). Red fox (Vulpes vulpes) infections have also been recently reported in some TB endemic regions in the Iberian Peninsula and France, with some of the infected animals shedding M. bovis in urine and feces. In order to understand the pathogenesis of M. bovis infection in foxes and the associated risk of transmission, 12 captive foxes (6 females and 6 males) were inoc-ulated orally with 2 × 107 colony-forming units of a French field isolate of M. bovis. Clinical samples (urine, feces and oropharyngeal swabs) were collected every four weeks and tested for molecular diagnosis and bacteriology. Serological responses were measured by IDEXX M. bovis Ab Test and Multi Antigen Print Immunoassay (MAPIA). At a post-mortem examination performed 12 weeks post infection (wpi), tissues were tested for the presence of M. bovis and associated gross and microscopic TB-like lesions. M. bovis was detected by PCR in bladder swabs of 3 animals at 12 wpi. It was also detected pre-mortem at different time points of the experiment in the oropharyngeal mu-cus of three individuals and in the feces of nine foxes, with two of them confirmed by bacteriology. All 12 foxes had at least 4 PCR positive samples (out of the 23 tested), and all but 1 fox had at least 1 culture positive sample. The culture negative fox was PCR positive in both retropharyngeal and mesenteric lymph nodes, in line with the results of the other animals. Seroconversion was observed in all foxes except one during the experiment, and in nine at the final time point. No gross visible lesions were found in any animal at the post-mortem examination. The histology showed small granulomas within the lymph nodes, tonsils, liver and lungs from eight animals, with the presence of few acid-fast bacilli. These results confirmed that all orally-infected foxes developed mild TB lesions but they were able to shed mycobacteria in about 75% of cases, 1 month post-infection (9 out 12 foxes). These results show that it is possible to induce typical TB infection experimentally in captive foxes, with measurable M. bovis excretion; such an experimental system could be useful for future evaluations of diagnostics and vaccines in this speciesSIThe French Ministry of Agriculture mainly financed the sampling and the analyses in the framework of the RFSA call on TB projects (Anses-DGAl credit agreement RFSA 2017-326). The animals and the running cost of the BSL3 facilities and technical resources were financed by the European Commission in the context of Horizon 2020?Vetbionet Transnational Access Activities (TNA) call. This work is also partially the result of the I+D+i research project RTI2018-096010-B-C21, funded by the Spanish MCIN/AEI/10.13039/501100011033/ Ministry of Science, Innovation and the European Regional Development Funds (FEDER Una manera de hacer Europa), and of PCTI 2021? 2023 (GRUPIN: IDI2021-000102) funded by Principado de Asturias and FEDE

Identifying cost-competitive greenhouse gas mitigation potential of French agriculture

The agriculture, forestry and other land use sector are responsible for 24% (10–12 Pg CO2e per year) of anthropogenic greenhouse gas (GHG) emissions worldwide, with concomitant opportunities for mitigation. A scientific panel used deliberative methods to identify ten technical measures comprising 26 sub-measures to reduce GHG emissions from agriculture in France. Their abatement potential and cost are compared. The proposed measures concern nitrogen (N) management, management practices that increase carbon stocks in soils and biomass, livestock diets, and energy production and consumption on farms. Results show that the total abatement potential can be divided into three parts. One third of the cumulated abatement potential corresponds to sub-measures that can be implemented at a negative technical cost. These sub-measures focus on increased efficiency in input use including N fertilisers, animal feed and energy. The second third are sub-measures with moderate cost (€25 per metric Mg of avoided CO2e). These require investment with no direct financial return, the purchase of particular inputs, dedicated labour time or involve production losses. Assuming additivity, the cumulated abatement is 32.3 Tg CO2e per year in 2030, but only 10 Tg (i.e. 10% of current agricultural emissions) when calculated under current inventory rules. This study confirms that a significant abatement potential exists in the agricultural sector, with two thirds of this potential at low or even negative cost. This is likely to be an underestimated as it is based on a status quo of the current agricultural system. Results also emphasise the need to upgrade inventory rules so that efforts to reduce emissions can be accounted for

Gradual internal reforming of methane: A demonstration

International audienceInternal steam reforming of natural gas in SOFCs is an attractive option offering faster response to load variations and significant cost reductions due to higher efficiency and to simpler balance of plant. An alternative approach for the direct use of natural gas has been previously proposed, i.e., the gradual internal steam reforming of methane. A set-up was developed for the demonstration of this concept that was tested up to high methane/water vapor ratios, i.e., CH4/H2O = 12, without carbon deposition. The gradual Internal Reforming of methane was demonstrated in this first approach, in spite of very low current densities (3.2 mA cm− 2 at 200 mV). The poor adherence between lanthanum chromite and electrolyte explains the high electrolyte/anode interfacial resistance that finally leads to low performances of lanthanum chromite as anode material. The current density was higher with CH4–H2O mixtures than with hydrogen, and was finally found to increase with the CH4/H2O ratio

Control and monitoring of oxygen content in molten metals. Application to lead and lead-bismuth melts

International audienceThe sources of error in potentiometric measurements of the oxygen activity in molten metals and the methods proposed to reduce these measurement errors are described. Specific constraints related to low temperature measurements are emphasized. Two set-ups for control of the oxygen activity in molten lead and lead-bismuth were developed. They involve zirconia-based cells, i.e., an oxygen pump and an oxygen probe. The performance of the set-ups was characterized. Attempts to reduce the working temperature (T < 4500°C) are discussed

A Solid Oxide Fuel Cell Operating in Gradual Internal Reforming Conditions under Pure Dry Methane

International audienceA planar solid oxide fuel cell (SOFC) was designed to be operated in gradual internal reforming conditions under pure dry methane. Stable operation was achieved for about 30 h. This result was obtained by deposition onto a Ni–yttria-stabilized zirconia cermet of a highly active and carbon-deposition-resistant catalyst layer consisting of Ir/CeO2. The performances of this layer were first evaluated in situ at open-circuit voltage, and then the principle of gradual internal reforming associated with electrocatalytic dissociation was demonstrated. The best cell performances with CH4/H2O=1/4 were 0.1  A  cm−2 at 0.55 V (about 55  mW cm−2) at 1173 K

Direct methane solid oxide fuel cell working by gradual internal steam reforming: Analysis of operation

International audienceA solid oxide fuel cell was designed to be operated with pure hydrocarbons, without additive or carrier gas, in order to bring technological simplifications, cost reductions and to extend the fuel flexibility limits. The cell was built-up from a conventional cell (LSM/YSZ/Ni-YSZ), to which was added a Ir–CeO2 catalyst layer at the anode side and an original current collecting system. The cell was first operated with steam in gradual internal reforming (GIR) conditions (R = [H2O]/[CH4] −2 at max power for 120 h. Small but abrupt deterioration of the performances was observed, but no carbon deposition. Electrical and chemical analysis of this degradation are provided.At total, the fuel cell was operated for more than 200 h in pure dry methane, demonstrating that gradual internal reforming actually occurred efficiently in the anode compartment, which make possible operation without reforming agent such as H2O or CO2 for other hydrocarbon fuels

Electrochemical promotion of NO reduction by propene on Pt/YSZ

International audienceThe reduction of NO by C3H6 in the presence of oxygen, is of great environmental importance. Platinum-based catalysts are very active but not selective towards N2 production and mainly convert NO into N2O, which participates to the greenhouse effect. Moreover, their operating temperature window is quite narrow. Electrochemical promotion was used to improve platinum catalytic behaviour. Platinum was deposited on YSZ (Y2O3 — stabilised ZrO2), an O2-conductor. It was found that a negative current increased the rate of NO reduction and CO2 formation. This rate enhancement was non-Faradaic with an apparent Faradaic efficiency (Λ) close to 180 indicating the manifestation of a NEMCA effect. However, the current application had no effect on the N2 selectivit

Kinetics of the O₂, Pt/YSZ interface at moderate temperature in the presence of C₃H₈ in the gas phase

International audienceThe catalytic activity of polycrystalline Pt deposited on Yttria Stabilized Zirconia (YSZ) for the oxidation of propane to CO2 can be affected using the effect of Non-faradaic Electrochemical Modification of Catalytic Activity (NEMCA). It was found that by applying positive overpotentials and thus, supplying O2- onto catalyst surface, up to 3.2-fold increase in the catalytic rate of 3H8 oxidation could be obtained at 365 °C. At 305 °C, no effect was evidenced. Using cyclic voltammetry and impedance spectroscopy, we have shown the modifications induced by the addition of C3H8 on the kinetics of the 02, Pt/YSZ interface in the temperature range 300–400 °C. A decrease of the coverage of adsorbed oxygen species produced electrochemically was evidenced as well as a decrease of the oxygen electrode reaction rate under anodic potential

Development of an Innovative Non-Destructive and Field-Oriented Method to Quantify the Bond Quality of Composite Strengthening Systems on Concrete Structures

International audienceOver the last 30 years, structural reinforcement and retrofitting with externally bonded composite materials have proven to be efficient and cost-effective solutions to increase both the safety and the lifespan of civil engineering structures, including nuclear power plants. The effectiveness of the strengthening system highly depends on the level of adhesion between the fiber-reinforced polymer (FRP) composite material and the concrete surface. Therefore, on-site evaluation of the bond quality is critical to assess the performance and predict the durability of the system in place. The direct tension pull-off test is most commonly used to quantify the adhesion level, but this standardized method has many drawbacks. In the present study, it is proposed to evaluate the bond properties by using a nondestructive test (NDT) derived from the standard pull-off test. This innovative test enables the measurement of an interfacial "stiffness" which may be used as a bond quality criterion. This paper gives an insight into the performance of the proposed NDT method, when applied in laboratory conditions to concrete slabs reinforced with bonded pultruded carbon FRP plates (CFRP). Three different epoxy adhesive systems with a broad range of Young's moduli were used for the specimens' preparation, in order to vary the stiffness of the concrete/CFRP interface. The purpose was to simulate different levels of interfacial adhesion that could be observed for a single adhesive system. It was shown that the test method was able to detect differences in the interface stiffness beyond experimental uncertainties, and it should therefore enable the detection of differences in the bond quality for a given adhesive system as well. The sensitivity of the NDT was then discussed, and its detection capabilities were predicted for standard field conditions. In the last part, strain measurements were collected during the NDT, thanks to distributed optical fiber sensors (DOFS) embedded in the adhesive joints of the strengthened specimens. An analysis of the strain profiles was found to provide complementary information on the quality of the adhesive bond

Nulling Stabilization in the Presence of Perturbation

International audienc