61 research outputs found
Phenotypic and genotypic study on antibiotic resistance and pathogenic factors of staphylococcus aureus isolates from small ruminant mastitis milk in south of italy (Sicily)
Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections
Processing of UHTCMCs
There is an increasing demand for advanced materials with temperature capability in highly corrosive environments for aerospace. Rocket nozzles of solid/hybrid rocket motors must survive harsh thermochemical and mechanical environments produced by high performance solid propellants (2700-3500°C). Thermal protection systems (TPS) for space vehicles flying at Mach 7 must withstand projected service temperatures up to 2500°C associated to convective heat fluxes up to 15 MWm-2 and intense mechanical vibrations at launch and re-entry into Earth’s atmosphere. The combination of extremely hot temperatures, chemically aggressive environments and rapid heating/cooling is beyond the capabilities of current materials.
As indicated by the previous talk, the main purpose of C3HARME is to design, develop, manufacture, test and validate a new class of out-performing, reliable, cost-effective and scalable Ultra High Temperature Ceramic Matrix Composites (UHTCMCs) based on C fibre preforms enriched with ultra-high temperature ceramics (UHTCs) and capable of in-situ repairing damage induced during operation in severe aerospace environments. Two main applications are envisaged: near-ZERO erosion rocket nozzles that must maintain dimensional stability during firing in combustion chambers, and near-ZERO ablation thermal protection systems enabling hypersonic space vehicles to maintain flight performance.
This talk aims at providing an indication of progress to date within Work Package 2, which is focused on the processing of Cf-ZrB2 UHTCMCs. Four primary routes are being investigated, these include: green forming of fibre reinforced UHT ceramics followed by spark plasma sintering; radio-frequency enhanced chemical vapour infiltration of UHTCMCs; reactive melt infiltration of UHTCMCs and polymer infiltration and pyrolysis of UHTCMCs. All four approaches will be outlined and conclusions drawn, plus there will be a brief mention of ongoing work into atomistic modelling of processes at materials interfaces and nanoparticle dispersion with a view to imparting self-healing properties.
Acknowledgements: This work has received funding from the European Union’s Horizon 2020 “Research and innovation programme” under grant agreement N°685594 (C3HARME
The long journey towards standards for engineering biosystems: Are the Molecular Biology and the Biotech communities ready to standardise?
Standards are the basis of technology: they allow rigorous description and exact measurement of properties, reliable reproducibility and a common “language” that enables different communities to work together. Molecular biology was in part created by physicists; yet, the field did not inherit the focus on the quantitation, the definition of system boundaries and the robust, unequivocal language that is characteristic of the other natural sciences. However, synthetic biology (SynBio) increasingly requires scientific, technical, operational and semantic standards for the field to become a full-fledged engineering discipline with a high level of accuracy in the design, manufacturing and performance of biological artefacts. Although the benefits of adopting standards are clear, the community is still largely reluctant to accept them, owing to concerns about adoption costs and losses in flexibility
An Experimental Investigation of Colonel Blotto Games
"This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a 'guerilla warfare' strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a 'stochastic complete coverage' strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields." (author's abstract)"Dieser Artikel untersucht das Verhalten von Individuen in einem 'constant-sum Colonel Blotto'-Spiel zwischen zwei Spielern, bei dem die Spieler mit unterschiedlichen Ressourcen ausgestattet sind und die erwartete Anzahl gewonnener Schlachtfelder maximieren. Die experimentellen Ergebnisse bestätigen alle wichtigen theoretischen Vorhersagen. Im Durchgang, in dem wie in einer Auktion der Sieg in einem Schlachtfeld deterministisch ist, wenden die Spieler, die sich im Nachteil befinden, eine 'Guerillataktik' an, und verteilen ihre Ressourcen stochastisch auf eine Teilmenge der Schlachtfelder. Spieler mit einem Vorteil verwenden eine Strategie der 'stochastischen vollständigen Abdeckung', indem sie zufällig eine positive Ressourcenmenge auf allen Schlachtfeldern positionieren. Im Durchgang, in dem sich der Gewinn eines Schlachtfeldes probabilistisch wie in einer Lotterie bestimmt, teilen beide Spieler ihre Ressourcen gleichmäßig auf alle Schlachtfelder auf." (Autorenreferat
N-glycosylation of mouse TRAIL-R and human TRAIL-R1 enhances TRAIL-induced death.
APO2L/TRAIL (TNF-related apoptosis-inducing ligand) induces death of tumor cells through two agonist receptors, TRAIL-R1 and TRAIL-R2. We demonstrate here that N-linked glycosylation (N-glyc) plays also an important regulatory role for TRAIL-R1-mediated and mouse TRAIL receptor (mTRAIL-R)-mediated apoptosis, but not for TRAIL-R2, which is devoid of N-glycans. Cells expressing N-glyc-defective mutants of TRAIL-R1 and mouse TRAIL-R were less sensitive to TRAIL than their wild-type counterparts. Defective apoptotic signaling by N-glyc-deficient TRAIL receptors was associated with lower TRAIL receptor aggregation and reduced DISC formation, but not with reduced TRAIL-binding affinity. Our results also indicate that TRAIL receptor N-glyc impacts immune evasion strategies. The cytomegalovirus (CMV) UL141 protein, which restricts cell-surface expression of human TRAIL death receptors, binds with significant higher affinity TRAIL-R1 lacking N-glyc, suggesting that this sugar modification may have evolved as a counterstrategy to prevent receptor inhibition by UL141. Altogether our findings demonstrate that N-glyc of TRAIL-R1 promotes TRAIL signaling and restricts virus-mediated inhibition
A Survey of Experimental Research on Contests, All-Pay Auctions and Tournaments
Many economic, political and social environments can be described as contests in which agents exert costly efforts while competing over the distribution of a scarce resource. These environments have been studied using Tullock contests, all-pay auctions and rankorder tournaments. This survey provides a review of experimental research on these three canonical contests. First, we review studies investigating the basic structure of contests, including the contest success function, number of players and prizes, spillovers and externalities, heterogeneity, and incomplete information. Second, we discuss dynamic contests and multi-battle contests. Then we review research on sabotage, feedback, bias, collusion, alliances, and contests between groups, as well as real-effort and field experiments. Finally, we discuss applications of contests to the study of legal systems, political competition, war, conflict avoidance, sales, and charities, and suggest directions for future research. (author's abstract
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