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25 p. This study was carried out to determine the occurrence and characteristics of enteropathogenic 18 Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) strains in cow’s milk, cheese 19 and dairy cattle farm environments, and to estimate distribution of antimicrobial resistance. A 20 collection of 18 atypical EPEC -aEPEC, 14 STEC, and one E. albertii was obtained and 21 characterized from 502 samples. Occurrence of aEPEC in cow’s milk was high (>6%) whereas non- 22 O157 STEC was isolated in ca. 2% of milk samples. Detection of these diarrheagenic E. coli was absent in more than 100 cheese samples obtained from raw milk. This is the first 23 report identifying 24 E. albertii (O69:HNM) in a dairy cattle farm. Nearly one-third of aEPEC strains showed 25 antimicrobial resistance, mostly presenting a multidrug resistance pattern. One clonal complex 26 (ST20 Cplx) containing aEPEC strains from milk and faecal samples was determined. Two STEC 27 strains belonged to serotypes with importance in human disease (O91:H21 and O55:H8) and were 28 isolated from air samples which suggests a high dissemination potential. Spanish bulk tank cow’s 29 milk can constitute an important source of aEPEC strains besides STEC, bearing multiple 30 antimicrobial resistance and with high diversity of both serotypes and genetic features linked to 31 potential human infection SI

Colistin is an antimicrobial polypeptide commonly employed for controlling and treating neonatal and post-weaning diarrhoea (PWD) diseases caused by Enterotoxigenic and Shiga toxin-producing Escherichia coli (ETEC and STEC). The plasmid-mediated colistin resistance gene, mcr-1 was first described in late 2015 and, since then, multiple studies have reported its global distribution. In addition, five different mcr genes have been identified. The aim of this study was to characterise the colistin-resistant E. coli clonal groups implicated in PWD in farms of intensive pig production. Of 186 ETEC and STEC isolated in Spain from 2006 to 2017, 76.9% showed resistance to colistin. Of those, 102 were mcr-4 carriers, 37 mcr-1 and 5 mcr-5, with co-occurrence of mcr-1/mcr-4, mcr-1/mcr-5 and mcr-4/mcr-5 in five isolates. Three different mcr-4 variants were detected, including the new mcr-4.4 and mcr-4.5 described here. Interestingly, the clonal group ST10-A (CH11-24) appears to be primarily responsible for the spread of mcr-4. In summary, our results show that the pig industry is an important reservoir of colistin-resistant E. coli, carriers of other additional risk genes, such as blaESBL. These food-producing animals might be spreading a cocktail of multiple resistances, posing a worrisome threat to human health.

International audience; CuCrZr is a precipitation hardening alloy, used for its good electrical and thermal properties combined to high mechanical properties. Using additive manufacturing technologies, and more specifically the laser powder bed fusion (L-PBF) process, allows designing highly complex parts such as compact and efficient CuCrZr heat exchangers. Additional understanding of the specific CuCrZr metallurgy during this manufacturing process is still needed to fully take advantages of these possibilities. This work aimed (i) to clarify the impact of the L-PBF process and post-fabrication heat treatments on the microstructure of L-PBF CuCrZr alloy, (ii) to determine the corresponding mechanical and electrical properties and (iii) to quantify the contributions of the different nano-scale strengthening mechanisms (nano-precipitation, dislocations, solid solution, grain size refinement) depending on the different heat treatments. The microstructures of the CuCrZr samples are carefully analyzed at different scales thanks to scanning electron and transmission electron microscopy, highlighting the effect of the different heat treatments. In all heat-treated samples, Cr nano-precipitates are uniformly dispersed in the Cu matrix; few Zr nano-precipitates are observed either at grain boundaries, next to Cr nano-precipitates, or inside the Cu matrix. Moreover, the mean grain size, dislocation density, mean radius and volume fraction of the Chromium nano-precipitates are measured. These data are introduced in the identified hardening mechanisms to estimate the yield strengths (YS) of the different analyzed CuCrZr microstructures. The results are compared to the experimental values, including those of a reference wrought heat-treated CuCrZr, and discussed. A good correlation is found between calculated and experimental values. For the first time, the main hardening mechanisms of L-PBF CuCrZr are quantified and the interest of the L-PBF+Direct Age Hardening (DAH) process route to get a high amount of Cr nano-precipitates is confirmed. The DAH applied to L-PBF materials provides high mechanical properties (184 HV1 hardness, YS=527 MPa, UTS=585MPa) while keeping a good elongation (14%) and electrical conductivity (42 MS.m-1). These results are due to a combination between (i) a high Cr nano-precipitates density, leading to a high precipitation hardening, and (ii) a high dislocation density associated to the presence of remaining solidification cells.

We investigate the physical properties of soap films and soap foams, the liquid phase of which contains a stable colloidal suspension of magnetic particles. The physical properties of such systems result from the equilibrium between the capillary forces, the gravity and the local magnetic forces. Therefore, they depend on the strength of an applied magnetic field or force, which makes it possible to act from outside on the system. We present the effect of the external field on the magnetic soap foams and films through two studies. First, we show that the dynamics of drainage in a freely suspended magnetic soap film is modified by an external magnetic field. Second, we present the control, via an external magnetic force, of the structure adopted by a monodisperse foam in a cylindrical tube. Those studies open possible applications of the ferrofluid foam, in the field of technological applications, but also as a model experimental system to study the drainage, the dynamical rheology, and the stability of soap foams.

In a Langmuir monolayer made of pure fluorescent NBD stearic acid, an ordered anisotropic phase was observed. The molecular structure of this solid phase was determined by electron scattering after transfer of the layer onto a solid substrate by the usual Langmuir-Blodgett technique. The electron diffraction pattern shows sharp peaks, indicating two-dimensional long-range positional order. The diffraction pattern is analyzed by comparison with Fourier transforms of models of molecular arrangements. The simulations reveal that the aliphatic chains are positioned along parallel strips, in agreement with optical studies.

A film of amphiphilic carbocyanine dye is spread on water and observed by fluorescence and polarized light techniques. With ClO4− counterions in the subphase, a first order transition occurs between an isotropic liquid phase and a solid one, made of birefringent elongated domains. On pure or acidified water, this transition takes place at a higher surface pressure, close to the monolayer collapse. When the carbocyanine is mixed with a fraction x of stearic acid another condensed phase appears, made of birefringent disks growing around a central disinclination. We report data concerning the phase diagram, and present a photometric method to measure the film thickness. We also discuss the nature of the different phases, and the possibility of a smectic-to-isotropic transition at x = 0.6.

Recent experiments and analyses involving vibration-to-vibration (VV) pumped carbon monoxide are presented. Pure CO, and COAr mixtures, in a flowing-gas cell, are vibrationally excited by absorption of CO laser radiation. The pump laser is a slow-flow liquid-nitrogen wall-cooled device, which can be operated in either Q -switched or cw mode for these experiments. There is output down to the v =1−0 vibrational transition ( Q -switched) or v =2−1 (cw). CO has been VV pumped in these experiments to very high vibrational quantum levels, at partial pressures up to 65 Torr. The rotational/translational mode temperature has been measured by emission spectroscopy of rotationally resolved Swan bands of C 2 formed from reaction of the VV pumped CO. Measured rotational mode temperatures up to 1500 K have been achieved with strong VV pumping. Low levels of ionization have been observed under these extreme pumping conditions. Results of time-resolved experiments exploring the kinetics are presented. These results are analyzed using a time-dependent kinetic master equation modeling code for the vibrational state kinetics.

Summary Four groups of rats were fed, for 45 days, one of the following semipurified diets containing sucrose 55% (w/w) and (a) casein 25%, (b) casein 24%, saponins (from Saponaria officinalis ) 1% (c) isolated soy protein 25%, (d) soy protein 24%, saponins 1%. The soy protein diet, compared to the casein one, produced an increase in the fecal excretion of neutral sterols on the 29th and 42nd days, without any modification in the liver, aorta and serum cholesterol concentrations. The effect of soy protein cannot be attributed to its saponin content but other substances associated to soy protein may interfere. With the casein diet, added saponins increased the fecal excretion of neutral sterols and bile acids and decreased liver and aorta cholesterol levels. Serum cholesterol was found unchanged. The effects of saponins were suppressed or greatly reduced with the soy protein diet. These results could be explained by binding of the sterols in insoluble forms.