80 research outputs found

    On the hardness of switching to a small number of edges

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    Seidel's switching is a graph operation which makes a given vertex adjacent to precisely those vertices to which it was non-adjacent before, while keeping the rest of the graph unchanged. Two graphs are called switching-equivalent if one can be made isomorphic to the other one by a sequence of switches. Jel\'inkov\'a et al. [DMTCS 13, no. 2, 2011] presented a proof that it is NP-complete to decide if the input graph can be switched to contain at most a given number of edges. There turns out to be a flaw in their proof. We present a correct proof. Furthermore, we prove that the problem remains NP-complete even when restricted to graphs whose density is bounded from above by an arbitrary fixed constant. This partially answers a question of Matou\v{s}ek and Wagner [Discrete Comput. Geom. 52, no. 1, 2014].Comment: 19 pages, 7 figures. An extended abstract submitted to COCOON 201

    A New Perspective on Clustered Planarity as a Combinatorial Embedding Problem

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    The clustered planarity problem (c-planarity) asks whether a hierarchically clustered graph admits a planar drawing such that the clusters can be nicely represented by regions. We introduce the cd-tree data structure and give a new characterization of c-planarity. It leads to efficient algorithms for c-planarity testing in the following cases. (i) Every cluster and every co-cluster (complement of a cluster) has at most two connected components. (ii) Every cluster has at most five outgoing edges. Moreover, the cd-tree reveals interesting connections between c-planarity and planarity with constraints on the order of edges around vertices. On one hand, this gives rise to a bunch of new open problems related to c-planarity, on the other hand it provides a new perspective on previous results.Comment: 17 pages, 2 figure

    Bifidobacterium longum CECT 7347 Modulates Immune Responses in a Gliadin-Induced Enteropathy Animal Model

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    Coeliac disease (CD) is an autoimmune disorder triggered by gluten proteins (gliadin) that involves innate and adaptive immunity. In this study, we hypothesise that the administration of Bifidobacterium longum CECT 7347, previously selected for reducing gliadin immunotoxic effects in vitro, could exert protective effects in an animal model of gliadin-induced enteropathy. The effects of this bacterium were evaluated in newborn rats fed gliadin alone or sensitised with interferon (IFN)-γ and fed gliadin. Jejunal tissue sections were collected for histological, NFκB mRNA expression and cytokine production analyses. Leukocyte populations and T-cell subsets were analysed in peripheral blood samples. The possible translocation of the bacterium to different organs was determined by plate counting and the composition of the colonic microbiota was quantified by real-time PCR. Feeding gliadin alone reduced enterocyte height and peripheral CD4+ cells, but increased CD4+/Foxp3+ T and CD8+ cells, while the simultaneous administration of B. longum CECT 7347 exerted opposite effects. Animals sensitised with IFN-γ and fed gliadin showed high cellular infiltration, reduced villi width and enterocyte height. Sensitised animals also exhibited increased NFκB mRNA expression and TNF-α production in tissue sections. B. longum CECT 7347 administration increased NFκB expression and IL-10, but reduced TNF-α, production in the enteropathy model. In sensitised gliadin-fed animals, CD4+, CD4+/Foxp3+ and CD8+ T cells increased, whereas the administration of B. longum CECT 7347 reduced CD4+ and CD4+/Foxp3+ cell populations and increased CD8+ T cell populations. The bifidobacterial strain administered represented between 75–95% of the total bifidobacteria isolated from all treated groups, and translocation to organs was not detected. These findings indicate that B. longum attenuates the production of inflammatory cytokines and the CD4+ T-cell mediated immune response in an animal model of gliadin-induced enteropathy

    Spectrum of gluten-related disorders: consensus on new nomenclature and classification

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    A decade ago celiac disease was considered extremely rare outside Europe and, therefore, was almost completely ignored by health care professionals. In only 10 years, key milestones have moved celiac disease from obscurity into the popular spotlight worldwide. Now we are observing another interesting phenomenon that is generating great confusion among health care professionals. The number of individuals embracing a gluten-free diet (GFD) appears much higher than the projected number of celiac disease patients, fueling a global market of gluten-free products approaching $2.5 billion (US) in global sales in 2010. This trend is supported by the notion that, along with celiac disease, other conditions related to the ingestion of gluten have emerged as health care concerns. This review will summarize our current knowledge about the three main forms of gluten reactions: allergic (wheat allergy), autoimmune (celiac disease, dermatitis herpetiformis and gluten ataxia) and possibly immune-mediated (gluten sensitivity), and also outline pathogenic, clinical and epidemiological differences and propose new nomenclature and classifications

    Seasonal dynamics of ergasilosis in reservoir fish

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    We evaluated ergasilosis seasonal dynamics at two reservoirs (Hubenov, Korycany) in the Morava River Basin (Czech Republic). Samples of fish were obtained at monthly intervals between April and October 2014. In total, 189 fish of 11 species were caught using electrofishing and seine nets. Highest overall values for E. sieboldi infection intensity and abundance were recorded at Hubenov in June and September. Prevalence ranged between 80 and 100%. Two highest peaks of infection intensity and abundance were recorded at Korycany in May and the second around September and October, prevalence ranging between 33 and 100%. As the nauplius and copepod stages of arthropods form part of the zooplankton assemblage, they will be found at highest numbers in reservoirs with low predatory pressure, i.e. where predatory fish suppress zooplanktonophagic fish species

    Hyposmia after vaccination against tick-borne encephalitis - case story

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    Introduction: During last several years the number of vaccination against infectious diseases increased. Therefore, it is expected to meet new adverse effects of this kind of prevention. In a case story we report a patient with hyposmia after receiving tick-borne encephalitis vaccine. Methods: Woman, 59 years old, came to our department due to loss of smell after vaccination against tick-born encephalitis. The vaccine was applied two weeks ago. She reported olfactory decrease second day after the vaccination. Other side effect symptoms of the vaccination were present as well - headache and tiredness. Regular ENT examination was performed including rhinoendoscopy and smell testing (OMT and Sniffin' Sticks Test). Patient underwent regular examination at neurology and infectology. X-ray of paranasal sinuses and MRI of head were performed. Smell testing was performed one month later. Results: There was no pathology found at ENT and neurological examination. Smell testing proved hyposmia in both tests (OMT 8 points, Sniffin' Sticks TDI 23.25 points). Serological analysis of antibody against tick-born encephalitis was negative and X-ray and MRI did not show any possible cause of smell loss. No systemic treatment was prescribed. One month later patient reported slight improvement of sense of smell. This was not proved by olfactometry (OMT 9 points, Sniffin' Sticks TDI 24.25 points). Conclusion: We present a patient with hyposmia after vaccination against tick-borne encephalitis. The question remains, whether this was caused by vaccine itself or this was coincidence of other etiology (postviral). Nevertheless, smell deterioration should be considered as a possible adverse effect of vaccination against tick-born encephalitis. Supported by: Grant project of the Ministry of Heath of the Czech Rebulic (No.1A/8667-4
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