Xylose substrate as the only nutrient in the operation of microbial fuel cells

Microbial fuel cells are bioelectrochemical devices converting chemical energy of organic compounds (i.e. biomass) into electrical energy by catalytic reactions of microbes under anaerobic conditions. The operation of two-chamber microbial fuel cells by Shewanella putrefaciens and mesophilic anaerobic sludge was studied comparatively, using xylose and glucose as solo substrates during the experiments. It was found that higher electric power was generated by the multicultural system than by the monoculture

Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to antimicrobial drugs. The aim of this study was to determine and compare the in vitro susceptibility of planktonic cells and biofilms of M. pachydermatis isolates to ketoconazole and itraconazole. The presence of biofilm formation was confirmed by crystal violet staining and absorbance measurement at 595 nm wavelength, and by a scanning electron microscopy method. Cell viability was determined by the Celltiter 96 Aqueous One solution assay containing a water-soluble tetrazolium compound (MTS) with absorbance measurement at 490 nm. Planktonic cell minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of ketoconazole and itraconazole were very low: MIC90 and MFC90 were 0.032 and 0.125 μg/ml for ketoconazole, while 0.063 and 0.25 μg/ml for itraconazole, respectively. Also, the half maximal effective concentrations (EC50) of itraconazole were higher for planktonic cells and biofilms compared to ketoconazole. The EC50 values of ketoconazole were 18–169 times higher and those of itraconazole 13–124 times higher for biofilms than for planktonic cells. Biofilm EC50 levels exceeded MICs 103–2060 times for ketoconazole and 84–1400 times for itraconazole. No significant difference was found between these values of the two substances. In conclusion, biofilms of all examined M. pachydermatis strains were much less susceptible to ketoconazole and itraconazole than their planktonic forms

Containment and equivalence of weighted automata: Probabilistic and max-plus cases

This paper surveys some results regarding decision problems for probabilistic and max-plus automata, such as containment and equivalence. Probabilistic and max-plus automata are part of the general family of weighted automata, whose semantics are maps from words to real values. Given two weighted automata, the equivalence problem asks whether their semantics are the same, and the containment problem whether one is point-wise smaller than the other one. These problems have been studied intensively and this paper will review some techniques used to show (un)decidability and state a list of open questions that still remain

A reconfigurations analogue of Brooks’ theorem.

Let G be a simple undirected graph on n vertices with maximum degree Δ. Brooks’ Theorem states that G has a Δ-colouring unless G is a complete graph, or a cycle with an odd number of vertices. To recolour G is to obtain a new proper colouring by changing the colour of one vertex. We show that from a k-colouring, k > Δ, a Δ-colouring of G can be obtained by a sequence of O(n 2) recolourings using only the original k colours unless G is a complete graph or a cycle with an odd number of vertices, or k = Δ + 1, G is Δ-regular and, for each vertex v in G, no two neighbours of v are coloured alike. We use this result to study the reconfiguration graph R k (G) of the k-colourings of G. The vertex set of R k (G) is the set of all possible k-colourings of G and two colourings are adjacent if they differ on exactly one vertex. It is known that if k ≤ Δ(G), then R k (G) might not be connected and it is possible that its connected components have superpolynomial diameter, if k ≥ Δ(G) + 2, then R k (G) is connected and has diameter O(n 2). We complete this structural classification by settling the missing case: if k = Δ(G) + 1, then R k (G) consists of isolated vertices and at most one further component which has diameter O(n 2). We also describe completely the computational complexity classification of the problem of deciding whether two k-colourings of a graph G of maximum degree Δ belong to the same component of R k (G) by settling the case k = Δ(G) + 1. The problem is O(n 2) time solvable for k = 3, PSPACE-complete for 4 ≤ k ≤ Δ(G), O(n) time solvable for k = Δ(G) + 1, O(1) time solvable for k ≥ Δ(G) + 2 (the answer is always yes)

Random Generation and Enumeration of Accessible Determinisitic Real-time Pushdown Automata

This papers presents a general framework for the uniform random generation of deterministic real-time accessible pushdown automata. A polynomial time algorithm to randomly generate a pushdown automaton having a fixed stack operations total size is proposed. The influence of the accepting condition (empty stack, final state) on the reachability of the generated automata is investigated.Comment: Frank Drewes. CIAA 2015, Aug 2015, Umea, Sweden. Springer, 9223, pp.12, 2015, Implementation and Application of Automata - 20th International Conferenc

Dependence, plans to quit, quitting self-efficacy and past cessation behaviours among menthol and other flavoured cigarette users in Europe: The EUREST-PLUS ITC Europe Surveys

INTRODUCTION: This study characterises smoking and cessationrelated behaviours among menthol and other flavoured cigarette users in Europe prior to the implementation of the European Tobacco Products Directive (TPD) ban on the sale of flavoured cigarettes. METHODS: An analysis of cross-sectional data from the 2016 EUREST-PLUS ITC Europe Surveys was conducted among a sample of 10760 adult smokers from eight European Union Member States. Respondents were classified as menthol, other flavoured, unflavoured, or no usual flavour cigarette users and compared on smoking and cessation behaviours and characteristics. Data were analysed in SPSS Complex Samples Package using bivariate and multivariate regression analyses adjusted for sociodemographic characteristics, dependence, and country. RESULTS: In bivariate analyses, cigarette flavour was significantly associated with all outcomes (p<0.001). After adjusting for sociodemographic characteristics, these associations attenuated but remained significant and in the same direction for dependence, self-efficacy, plans to quit, past quit attempts, and ever e-cigarette use. In fully adjusted models, compared to smokers of non-flavoured cigarettes, menthol smokers were less likely to smoke daily (AOR=0.47, 95% CI: 0.32–0.71), smoke within 30 min of waking (0.52,0.43–0.64), consider themselves addicted (0.74,0.59–0.94), and more likely to have ever used e-cigarettes (1.26,1.00–1.57); other flavoured cigarette smokers were less likely to smoke daily (0.33,0.15–0.77), and have higher self-efficacy (1.82,1.20–2.77); no usual flavour smokers were less likely to smoke daily (0.34,0.22–0.51), smoke within 30 min of waking (0.66,0.55–0.80), consider themselves addicted (0.65,0.52–0.78), have ever made a quit attempt (0.69,0.58– 0.84), have ever used e-cigarettes (0.66,0.54–0.82), and had higher self-efficacy (1.46,1.19–1.80). CONCLUSIONS: Smokers of different cigarette flavours in Europe differ on smoking and cessation characteristics. The lower dependence of menthol cigarette smokers could lead to greater success rates if quit attempts are made, however cross-country differences in smoking behaviours and quitting intentions could lead to the TPD ban on cigarette flavours having differential impact if not accompanied by additional measures, such as smoking cessation support

Revisiting the growth of polyregular functions: output languages, weighted automata and unary inputs

Polyregular functions are the class of string-to-string functions definable by pebble transducers (an extension of finite automata) or equivalently by MSO interpretations (a logical formalism). Their output length is bounded by a polynomial in the input length: a function computed by a $k$-pebble transducer or by a $k$-dimensional MSO interpretation has growth rate $O(n^k)$. Boja\'nczyk has recently shown that the converse holds for MSO interpretations, but not for pebble transducers. We give significantly simplified proofs of those two results, extending the former to first-order interpretations by reduction to an elementary property of $\mathbb{N}$-weighted automata. For any $k$, we also prove the stronger statement that there is some quadratic polyregular function whose output language differs from that of any $k$-fold composition of macro tree transducers (and which therefore cannot be computed by any $k$-pebble transducer). In the special case of unary input alphabets, we show that $k$ pebbles suffice to compute polyregular functions of growth $O(n^k)$. This is obtained as a corollary of a basis of simple word sequences whose ultimately periodic combinations generate all polyregular functions with unary input. Finally, we study polyregular and polyblind functions between unary alphabets (i.e. integer sequences), as well as their first-order subclasses.Comment: 27 pages, not submitted ye