International Clostridium difficile animal strain collection and large diversity of animal associated strains

Background: Clostridium difficile is an important cause of intestinal infections in some animal species and animals might be a reservoir for community associated human infections. Here we describe a collection of animal associated C. difficile strains from 12 countries based on inclusion criteria of one strain (PCR ribotype) per animal species per laboratory. Results: Altogether 112 isolates were collected and distributed into 38 PCR ribotypes with agarose based approach and 50 PCR ribotypes with sequencer based approach. Four PCR ribotypes were most prevalent in terms of number of isolates as well as in terms of number of different host species: 078 (14.3% of isolates; 4 hosts), 014/020 (11.6%; 8 hosts); 002 (5.4%; 4 hosts) and 012 (5.4%; 5 hosts). Two animal hosts were best represented; cattle with 31 isolates (20 PCR ribotypes; 7 countries) and pigs with 31 isolates (16 PCR ribotypes; 10 countries). Conclusions: This results show that although PCR ribotype 078 is often reported as the major animal C. difficile type, especially in pigs, the variability of strains in pigs and other animal hosts is substantial. Most common human PCR ribotypes (014/020 and 002) are also among most prevalent animal associated C. difficile strains worldwide. The widespread dissemination of toxigenic C. difficile and the considerable overlap in strain distribution between species furthers concerns about interspecies, including zoonotic, transmission of this critically important pathogen

Economic processing of metal matrix composites by combination of direct pressure sintering and thixo forging

In der Vergangenheit konnten Metall-Matrix-Verbundwerkstoffe trotz vielversprechender Eigenschaften die in sie gesetzten Erwartungen hinsichtlich eines breiten Anwendungsspektrums nicht erfüllen. Dies ist dadurch bedingt, dass der Einsatz solcher MMC-Werkstoffe aufgrund der kostenintensiven Herstellung der Materialien und der Schwierigkeiten bei der Verarbeitung bis heute noch nicht wirtschaftlich realisiert werden kann. Die hier vorgestellte Verfahrenskombination des Drucksinterns mit anschließendem Thixoschmieden stellt eine neuartige und effiziente Prozessroute zur Herstellung von MMC-Bauteilen in (near-) net-shape Qualität dar. Ein großer Vorteil der direkten Drucksintertechnologie ist dabei die Ausnutzung der Freiheiten der Pulvermetallurgie. Auf diese Weise kann bei der Komposition von Matrixlegierung und keramischer Verstärkung eine Anpassung des Werkstoffes an den späteren Belastungsfall erfolgen. Durch erste Untersuchungen mit verschiedensten Kombinationen von Aluminium-Matrizes und Verstärkungsphasen am IFAM Dresden konnte die Effizienz dieser Technologie bereits nachgewiesen werden. Die Weiterverarbeitung der druckgesinterten Halbzeuge mit verstärkenden SiC-Anteilen von bis zu 40% erfolgte am IFÜ Stuttgart mittels des Thixoschmiedeverfahrens. Anhand einer komplexen Hebelgeometrie wurde die prinzipielle Verarbeitung solcher MMC-Werkstoffe im teilflüssigen Materialzustand nachgewiesen. Dabei konnte gezeigt werden, dass das im vorangegangenen Prozessschritt eingestellte homogene Materialgefüge auch nach der Verarbeitung im teilflüssigen Zustand erhalten blieb, und zudem eine Verdichtung des Materials bis hin zur theoretischen Dichte des Werkstoffes eintrat

Semi-solid Formgebung von AMC-Werkstoffen: Potentiale einer neuartigen Prozessroute zur Herstellung von Hochleistungskomponenten

With regard to the processing of particle-reinforced aluminum matrix composites (AMC) into complex parts with net-shape quality, high dimensional accuracy and favorable mechanical properties, the semi-solid forming technology provides good perspectives. In this context, this article deals with a new process flow for the production of high-performance components from such AMC materials and presents its potential

ISO.Wind - A monitoring system for wind parks using passive radar

Intelligent wind park monitoring systems may allow cutting the levelized cost of wind-generated electricity by deploying maintenance personnel more efficiently. The non-contacting passive radar technology and advanced sensing technologies on the plant side offer significant potential for such monitoring systems. The goal of the 3-year-long project ISO.Wind is to identify the most cost-efficient sensing technologies to detect maintenance-relevant damages and to use them for a wind park monitoring system. For this purpose a commercial 3MW wind turbine is instrumented with strain gauges following IEC standard 61400-13 and a network of accelerometers. It is also monitored by passive radar technology. A learning algorithm is developed and fed with available data from the sensor systems and operational data from the instrumented wind turbine. The algorithm is capable of detecting operational patterns and damage cases of the wind turbine. A graphic user interface illustrates these conditions in a comprehensible way. First field measurements show the suitability of the passive radar technology to detect the damage-relevant dynamics of the instrumented wind turbine. Validated simulations of typical damage cases prove that both instrumentation on the plant side and the passive radar sensing technology allow reliable damage detection for the examined wind turbine

Third and fifth harmonic responses in viscous liquids

International audienceWe review the works devoted to third and fifth harmonic susceptibilities in glasses, namely χ (3) 3 and χ (5) 5. We explain why these nonlinear responses are especially well adapted to test whether or not some amorphous correlations develop upon cooling. We show that the experimental frequency and temperature dependences of χ (3) 3 and of χ (5) 5 have anomalous features, since their behavior is qualitatively different to that of an ideal gas, which is the high-temperature limit of a fluid. Most of the works have interpreted this anomalous behavior as reflecting the growth, upon cooling, of amorphously ordered domains, as predicted by the general framework of Bouchaud and Biroli (BB). We explain why most—if not all—of the challenging interpretations can be recast in a way which is consistent with that of Bouchaud and Biroli. Finally, the comparison of the anomalous features of χ (5) 5 and of χ (3) 3 shows that the amorphously ordered domains are compact, i.e., the fractal dimension d f is close to the dimension d of space. This suggests that the glass transition of molecular liquids corresponds to a new universality class of critical phenomena