Identification of K 99 and 987 P attaching antigens of Escherichia coli in the pig in France

Les auteurs font état de l’identification en France des antigènes d’attachement K 99 et 987 P, à partir de souches d ’Escherichia coli responsables de diarrhée du porcelet nouveau-né. Ils discutent à ce propos des difficultés du diagnostic, des enquêtes épidémiologiques et de l’intérêt de l’incorporation de ces nouvelles valences dans les vaccins.Identification of K 99 and 987 P attaching antigens of ESCHERICHIA COLI IN THE PIG IN FRANCE The authors relate the detection of K 99 and 987 P pilus antigens on Escherichia coli enteropathogens for piglets in France. They dis cuss about the difficulty of the diagnostic and the prevalence of these pilus antigens and the interest of their incorporation in the vaccines

Serological surwey of antibodies frequency in France against anti-K 88, anti-K 99, anti-987 P, anti-F 41 of Escherichia coli on sow

Devant les difficultés d'isolement des souches d 'Escherichia coli, pourvues d’antigènes d’attachement différents des K88, les auteurs pré sentent les résultats d’une enquête sérologique concernant 200 truies environ, de 13 élevages différents. 41.8 % des truies possèdent des anticorps anti-K 88, 59,5 % anti-K 99, 78 % anti-987 P et 62,5 % anti-F 41, dont 87,5 % vis-à-vis de plusieurs pili. Après discussion sur l’importance respective de ces anticorps et de leur répartition à l’intérieur d’un même élevage et pour un même animal, les auteurs concluent sur la preuve de l’existence en France de souches entérotoxinogènes pourvues de nouveaux pili et sur l’intérêt de leur incorporation dans les vaccins destinés à lutter contre la colibacillose des porcelets nouveau-nés.With regards to difficulties to isolated piliated strains of enterotoxi genic Escherichia coli different from K 88, the authors yield results of serological survey of about 200 sows from 13 different herds. 41.8 % of the sows have antibodies against K 88, 59,5 % against K 99, 78 % against 987 P and 62,5 % whose 87,5 % against several pili. After discussion of respective importance of these antibodies and of their share, among one herd a same animal, the authors conclude in favor of existence in France of enteropathogenic strains with new pili and of the interest of incorporating these structures in the bacterines for the fighting against neonatal colibacillosis

Ti–Si–C thin films produced by magnetron sputtering : correlation between physical properties, mechanical properties and tribological behavior

Ti–Si–C thin films were deposited onto silicon, stainless steel and high-speed steel substrates by magnetron sputtering, using different chamber configurations. The composition of the produced films was obtained by Electron Probe Micro-Analysis (EPMA) and the structure by X-ray diffraction (XRD). The hardness and residual stresses were obtained by depth-sensing indentation and substrate deflection measurements (using Stoney’s equation), respectively. The tribological behavior of the produced films was studied by pin-on-disc. The increase of the concentration of non-metallic elements (carbon and silicon) caused significant changes in their properties. Structural analysis revealed the possibility of the coexistence of different phases in the prepared films, namely Ti metallic phase ( alpha-Ti or beta-Ti) in the films with higher Ti content. The coatings with highest carbon contents, exhibited mainly a sub-stoichiometric fcc NaCl TiC-type structure. These structural changes were also confirmed by resistivity measurements, whose values ranged from 10E3 Ohm/sq for low non-metal concentration, up to 10E6 Ohm /sq for the highest metalloid concentration. Astrong increase of hardness and residual stresses was observed with the increase of the non-metal concentration in the films. The hardness (H) values ranged between 11 and 27 GPa, with a clear dependence on both crystalline structure and composition features. Following the mechanical behavior, the tribological results showed similar trends, with both friction coefficients and wear revealing also a straight correlation with the composition and crystalline structure of the coatings

Optimization and thermal stability of TiAlN-Mo multilayers

In this work we focus on the optimization and thermal stability of nanocomposite TiAlN/Mo multilayers that were produced by reactive magnetron sputtering on high-speed steel substrates, with modulation periods below 5 nm. These multilayers were annealed between 600– 900 ºC for 1 h in a vacuum furnace. Preliminary X-ray diffraction results reveal that these coatings are very stable up to 900 ºC, since the multilayer chemical modulation is not severely affected. At intermediate annealing temperatures the modulation period decreases due to interdiffusion at the interface, resulting in a thicker interface between metal/nitride and hence decreasing the thickness of those layers.Portuguese FCT/MCES scientific program

Enquête sur la colibacillose du porcelet nouveau né

Renault Lucien, Le Bourhis Elizabeth, Maire Cl., Vaissaire Josée. Enquête sur la colibacillose du porcelet nouveau-né. In: Bulletin de l'Académie Vétérinaire de France tome 128 n°8, 1975. pp. 397-403

Enquête sur la colibacillose du porcelet au moment du sevrage

Les auteurs ont fait l'étude sérologique de 113 souches d’Escherichia coli isolées de porcelets atteints de colibacillose à l'occasion du sevrage. Les résultats indiquent que la majorité appartient à des souches entéro- pathogènes et principalement aux sérogroupes 0149 : K 91, K 88 a, c et 0141 : K 85 a, c

Effect of thermal treatments on the structure of MoNxOy thin films

Article in PressMoNxOy films were deposited on steel substrates by dc reactive magnetron sputtering. The depositions were carried out from a pure molybdenum target, varying the flow rate of reactive gases. X-ray diffraction (XRD) results revealed the occurrence of cubic MoNx and hexagonal (d-MoN) phases for the films with high nitrogen flow rates. The increase of oxygen content induces the decrease of the grain size of the molybdenum nitride crystallites. The thermal stability of a set of samples was studied in vacuum, for an annealing time of 1 h, for temperatures ranging from 500 to 800 C in 100 C steps. The results showed that pure molybdenum nitride films changed their structure from a meta-stable cubic MoN to hexagonal d-MoN and cubic g-Mo2N-type structures with increasing annealing temperatures. The samples with molybdenum nitride films evidenced a good thermal stability, but those with molybdenum oxynitride coatings showed a tendency to detach with the increase of the annealing temperature.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/CTM/38086/200

ZrOxNy decorative thin films prepared by the reactive gas pulsing process

Zirconium oxynitride thin films were deposited by dc reactive magnetron sputtering. A zirconium metallic target was sputtered in an Ar + N2 + O2 atmosphere. Argon and nitrogen flow rates were maintained constant whereas oxygen was pulsed during the deposition, implementing the reactive gas pulsing process (RGPP). A constant pulsing period T = 3 s was used following an exponential periodic signal versus time. The introduction time of oxygen was systematically changed from 17% to 83% of the period. The RGPP allowed the synthesis of ZrOxNy films with tuneable metalloid concentrations adjusting the introduction time of the oxygen. Composition and structural variations associated with mechanical, optical and electrical properties exhibited a smooth transition, from metallic-like characteristics, typical of the fcc-ZrN phase, to semi-conducting behaviour corresponding to a mixture of orthorhombic-Zr3N4(O) and γ -Zr2ON2 crystalline phases.Fundação para a Ciência e Tecnologia (FCT) - PTDC/CTM/69362/2006

Recognition of vitamin B metabolites by mucosal-associated invariant T cells

The mucosal-associated invariant T-cell antigen receptor (MAIT TCR) recognizes MR1 presenting vitamin B metabolites. Here we describe the structures of a human MAIT TCR in complex with human MR1 presenting a non-stimulatory ligand derived from folic acid and an agonist ligand derived from a riboflavin metabolite. For both vitamin B antigens, the MAIT TCR docks in a conserved manner above MR1, thus acting as an innate-like pattern recognition receptor. The invariant MAIT TCR a-chain usage is attributable to MR1-mediated interactions that prise open the MR1 cleft to allow contact with the vitamin B metabolite. Although the non-stimulatory antigen does not contact the MAIT TCR, the stimulatory antigen does. This results in a higher affinity of the MAIT TCR for a stimulatory antigen in comparison with a non-stimulatory antigen. We formally demonstrate a structural basis for MAIT TCR recognition of vitamin B metabolites, while illuminating how TCRs recognize microbial metabolic signatures