Phase transitions of extended-range probabilistic cellular automata with two absorbing states

We study phase transitions in a long-range one-dimensional cellular automaton with two symmetric absorbing states. It includes and extends several other models, like the Ising and Domany-Kinzel ones. It is characterized by a competing ferromagnetic linear coupling and an antiferromagnetic nonlinear one. Despite its simplicity, this model exhibits an extremely rich phase diagram. We present numerical results and mean-field approximations.Comment: New and expanded versio

Synchronization of non-chaotic dynamical systems

A synchronization mechanism driven by annealed noise is studied for two replicas of a coupled-map lattice which exhibits stable chaos (SC), i.e. irregular behavior despite a negative Lyapunov spectrum. We show that the observed synchronization transition, on changing the strength of the stochastic coupling between replicas, belongs to the directed percolation universality class. This result is consistent with the behavior of chaotic deterministic cellular automata (DCA), supporting the equivalence Ansatz between SC models and DCA. The coupling threshold above which the two system replicas synchronize is strictly related to the propagation velocity of perturbations in the system.Comment: 16 pages + 12 figures, new and extended versio

De Gustibus Disputandum

We propose a simple method to predict individuals' expectations about products using a knowledge network. As a complementary result, we show that the method is able, under certain conditions, to extract hidden information at neural level from a customers' choices database

In vivo analysis of staphylococcus aureus-infected mice reveals differential temporal and spatial expression patterns of fhuD2

Staphylococcus aureus is an opportunistic human pathogen and a major cause of invasive infections such as bacteremia, endocarditis, pneumonia and wound infections. FhuD2 is a staphylococcal lipoprotein involved in the uptake of iron-hydroxymate and is under the control of the iron uptake regulator Fur. The protein is part of an investigational multi-component vaccine formulation that has shown protective efficacy in several murine models of infection. Even though fhuD2 expression was shown to be upregulated in murine kidneys infected with S. aureus, it is unknown whether the bacterium undergoes increased iron deprivation during prolonged infection. Furthermore, different infection niches of S. aureus might provide different environments and iron availability resulting in different fhuD2 expression pattern within different host organs. To address these questions, we characterized the in vitro expression of the fhuD2 gene and confirmed Fur-dependent iron-regulation of its expression. We further investigated its expression in mice infected with a bioluminescent reporter strain of S. aureus expressing the luciferase operon under the control of the fhuD2 promoter. The emission of bioluminescence in different organs was followed over a seven-day time course, as well as quantitative real-time PCR analysis of the RNA transcribed from the endogenous fhuD2 gene. Using this approach, we could show that fhuD2 expression was induced during infection in all organs analyzed and that differences in expression were observed in the temporal expression profiles, and between infected organs. Our data suggest that S. aureus undergoes increased iron deprivation during progression of infection in diverse host organs and accordingly induces dedicated iron acquisition mechanisms. Since FhuD2 plays a central role in providing the pathogen with the required iron, further knowledge of the patterns of fhuD2 expression in vivo during infection is instrumental in better defining the role of this antigen in S. aureus pathogenesis and as a vaccine antigen

In vivo gene expression profiling of Staphylococcus aureus during infection informs design of stemless leukocidins LukE and -D as detoxified vaccine candidates

A.F.H. and L.L. were funded by Marie Sklodowska-Curie Intra-European Fellowships (PIEF-GA-2012-328377 and PIEF-GA-2013-623168, respectively).Staphylococcus aureus is a clinically important bacterial pathogen that has become resistant to treatment with most routinely used antibiotics. Alternative strategies, such as vaccination and phage therapy, are therefore actively being investigated to prevent or combat staphylococcal infections. Vaccination requires that vaccine targets are expressed at sufficient quantities during infection so that they can be targeted by the host’s immune system. While our knowledge of in vitro expression levels of putative vaccine candidates is comprehensive, crucial in vivo expression data are scarce and promising vaccine candidates during in vitro assessment often prove ineffective in preventing S. aureus infection. Here, we show how a newly developed high-throughput quantitative reverse transcription-PCR (qRT-PCR) assay monitoring the expression of 84 staphylococcal genes encoding mostly virulence factors can inform the selection and design of effective vaccine candidates against staphylococcal infections. We show that this assay can accurately quantify mRNA expression levels of these genes in several host organs relying only on very limited amounts of bacterial mRNA in each sample. We selected two highly expressed genes, lukE and lukD, encoding pore-forming leukotoxins, to inform the design of detoxified recombinant proteins and showed that immunization with recombinant genetically detoxified LukED antigens conferred protection against staphylococcal skin infection in mice. Consequently, knowledge of in vivo-expressed virulence determinants can be successfully deployed to identify and select promising candidates for optimized design of effective vaccine antigens against S. aureus. Notably, this approach should be broadly applicable to numerous other pathogens.Publisher PDFPeer reviewe

Robotic rectal surgery: State of the art

Laparoscopic rectal surgery has demonstrated its superiority over the open approach, however it still has some technical limitations that lead to the development of robotic platforms. Nevertheless the literature on this topic is rapidly expanding there is still no consensus about benefits of robotic rectal cancer surgery over the laparoscopic one. For this reason a review of all the literature examining robotic surgery for rectal cancer was performed. Two reviewers independently conducted a search of electronic databases (PubMed and EMBASE) using the key words “rectum”, “rectal”, “cancer”, “laparoscopy”, “robot”. After the initial screen of 266 articles, 43 papers were selected for review. A total of 3013 patients were included in the review. The most commonly performed intervention was low anterior resection (1450 patients, 48.1%), followed by anterior resections (997 patients, 33%), ultra-low anterior resections (393 patients, 13%) and abdominoperineal resections (173 patients, 5.7%). Robotic rectal surgery seems to offer potential advantages especially in low anterior resections with lower conversions rates and better preservation of the autonomic function. Quality of mesorectum and status of and circumferential resection margins are similar to those obtained with conventional laparoscopy even if robotic rectal surgery is undoubtedly associated with longer operative times. This review demonstrated that robotic rectal surgery is both safe and feasible but there is no evidence of its superiority over laparoscopy in terms of postoperative, clinical outcomes and incidence of complications. In conclusion robotic rectal surgery seems to overcome some of technical limitations of conventional laparoscopic surgery especially for tumors requiring low and ultra-low anterior resections but this technical improvement seems not to provide, until now, any significant clinical advantages to the patients