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Kridlo O.,University of Pavol Jozef Safarik | Ojeda-Aciego M.,University of Malaga
CEUR Workshop Proceedings | Year: 2016

This work focuses on the definition of a consequence relation between contexts with which we can decide whether certain contextual information is a logical consequence from a set of contexts considered as underlying hypotheses. © 2016, CEUR-WS. All rights reserved.

Kridlo O.,University of Pavol Jozef Safarik | Ojeda-Aciego M.,University of Malaga
Annals of Mathematics and Artificial Intelligence | Year: 2014

Continuing our categorical study of L-fuzzy extensions of formal concept analysis, we provide a representation theorem for the category of L-Chu correspondences between L-formal contexts and prove that it is equivalent to the category of completely lattice L-ordered sets. © 2014, Springer International Publishing Switzerland.

Kridlo O.,University of Pavol Jozef Safarik | Ojeda-Aciego M.,University of Malaga
CEUR Workshop Proceedings | Year: 2013

We continue our study of the general notion of L-Chu correspondence by introducing the category CRL-ChuCors incorporating residuation to the underlying complete lattice L, specifically, on the basis of a residuation-preserving isotone Galois connection λ Then, the L-bonds are generalized within this same framework, and its structure is related to that of the extent of a suitably defined λ-direct product. © paper author(s), 2013.

Balint S.,ICFO - Institute of Photonic Sciences | Balint S.,University of Pavol Jozef Safarik | Rao S.,ICFO - Institute of Photonic Sciences | Marro M.,ICFO - Institute of Photonic Sciences | And 4 more authors.
Journal of Raman Spectroscopy | Year: 2011

The local pH inside individual live glioma (U-87 MG) cancer cells was monitored after treatment by the photodynamic therapy drug 6-methyl-1,3,8- trihydroxyanthraquinone (emodin). The cellular pH is tracked by the real-time measurement of the surface-enhanced Raman scattering (SERS) from a probe that is embedded in the cell. The probe is a micrometer-sized silica bead that is covered by nanosized silver colloids, which enhance Raman signal, and 4-mercaptobenzoic acid (pMBA) whose molecular vibrations and resulting Raman spectrum are sensitive to pH. Visible excitation at different light dosages is used to activate the drug. The results indicate cell maintenance of internal pH and cell death at low and high light dosage, respectively. We demonstrate that these SERS probes are an effective tool for ex vivo pH monitoring in a live cell thanks to their high optical sensitivity and noninvasive usage. Copyright © 2011 John Wiley & Sons, Ltd.

Huntosova V.,University of Pavol Jozef Safarik | Huntosova V.,University Pierre and Marie Curie | Nadova Z.,University of Pavol Jozef Safarik | Dzurova L.,University of Pavol Jozef Safarik | And 4 more authors.
Photochemical and Photobiological Sciences | Year: 2012

Hypericin (Hyp) is a hydrophobic natural photosensitizer that is considered to be a promising molecule for photodynamic treatment of tumor cells and photo-diagnosis of early epithelial cancers. Its hydrophobicity is the main driving force that governs its redistribution process. Low-density lipoproteins (LDL), a natural in vivo carrier of cholesterol present in the vascular system, have been used for targeted transport of Hyp to U87 glioma cells. For low Hyp-LDL ratios (≤10:1), the cellular uptake of Hyp is characterized by endocytosis of the [Hyp-LDL] complex, while Hyp alone can enter cells by passive diffusion. Photo-induced cell death and the mitochondrial membrane potential, observed for glioma cells after various times of incubation with the [Hyp-LDL] complex or Hyp alone, were monitored by flow-cytometry analysis using Annexin-V-FITC propidium iodide and DiOC 6(3) staining. Differences of the results are discussed in view of the respective dynamic subcellular distributions of the drugs that were obtained by co-localization experiments using confocal fluorescence microscopy. In order to give clear evidence of specific intracellular localization and to identify possible Hyp aggregation in cellular organelles, fluorescence resonance energy transfer (FRET) between selected fluorescent organelle probes and Hyp was also assessed. It is shown, that the observed photo-induced cell deaths can be correlated with the sub-cellular distribution of the active fluorescent monomer form of Hyp in lysosomes (as determined from steady-state fluorescence experiments), but that possible aggregation of Hyp in some organelles, as determined from FRET experiments, should be taken into account for interpretation of the real dynamics of the subcellular redistribution. Results of the present study underline the fact that photo-induced cell death processes are strongly influences by dynamics of Hyp subcellular redistribution processes involving monomer-aggregate equilibrium. Such an observation should be taken in consideration for further optimization of Hyp in vivo PDT applications. © 2012 The Royal Society of Chemistry and Owner Societies.

Feckova Z.,University of Pavol Jozef Safarik | Feckova Z.,Matej Bel University | Toma-Ik B.,Matej Bel University | Toma-Ik B.,Czech Technical University
Acta Physica Polonica B, Proceedings Supplement | Year: 2015

Hydrodynamic modelling of quark-gluon plasma requires sophisticated numerical schemes that have low numerical viscosity and are able to cope with high gradients of energy density that may appear in initial conditions. We propose to use the Godunov method with an exact Riemann solver for ideal hydrodynamic modelling to meet these conditions. We present the results of numerical tests of the method, such as the sound wave propagation and the shock tube problem, which show both high precision of the method and low numerical viscosity.

Piskova L.,University of Pavol Jozef Safarik | Horvath T.,University of Pavol Jozef Safarik
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

This paper introduces a new algorithm for computing concept lattices from very sparse large-scale formal contexts (input data) where the number of attributes per object is small. The algorithm consists of two steps: generate a diagram of a formal context and compute the concept lattice of the formal context using the diagram built in the previous step. The algorithm is experimentally evaluated and compared with algorithms AddExtent and CHARM-L. © 2014 Springer International Publishing.

Tokar T.,University of Pavol Jozef Safarik | Ulicn J.,University of Pavol Jozef Safarik
Physica A: Statistical Mechanics and its Applications | Year: 2012

In spite of attention devoted to molecular mechanisms of apoptosis, the details of functioning of one crucial component-the Bcl-2 apoptotic switch-are not completely understood. There are two competing mechanisms of its internal working - the indirect activation and the direct activation. In the absence of conclusive experimental data, we have used computational modeling to assess the properties of both mechanisms and their suitability to act as a biological switch. Since the two mechanisms form opposite poles of continuum of Bcl-2 molecular interaction models, we have constructed more general models including these two models as extreme cases. By studying the relationship between model parameters and the steady-state response we have found optimal interaction patterns which reproduce the behavior of the Bcl-2 apoptotic switch. Our results show, that stimulus-response ultrasensitivity is negatively affected by spontaneous activation of Bcl-2 effectors. We found that ultrasensitivity requires effectors activation, mediated by another subgroup of Bcl-2 proteins - activators. We have shown that the auto-activation of monomeric effector forms provides an ultrasensitivity enhancing feedback loop. Thorough robustness analysis revealed that the interaction pattern postulated in the direct activation hypothesis is able to conserve stimulus-response switching characteristics for wide range changes of its internal parameters. The robustness of the switch against the variation of the reaction parameter is strongly reduced for the intermediate hybrid model and even more for the indirect part of the models. Computer simulations of the more general model presented here suggest, that stimulus-response ultrasensitivity is an emergent property of the direct activation model that is unlikely to occur in the model of indirect activation. Introduction of indirect-model-specific interactions does not provide a better explanation of the Bcl-2 switch functionality compared to the direct model. © 2012 Elsevier B.V. All rights reserved.

Soltes M.,University of Pavol Jozef Safarik | Radonak J.,University of Pavol Jozef Safarik
Wideochirurgia I Inne Techniki Maloinwazyjne | Year: 2014

Introduction: Several preoperative scoring systems have been proposed to predict the difficulty of laparoscopic cholecystectomy in order to optimize the results of surgical treatment by either selection of patients for the procedure or providing an adequately experienced surgical team for a given patient. Nevertheless, none of them has achieved significant penetration into everyday practice. Aim: To propose and validate a novel risk score based on the patient's history, physical examination and abdominal ultrasonography parameters. Material and methods: The risk score was defined by the presence of the following risk factors: male sex, biliary colic within the last 3 weeks prior to surgery, history of acute cholecystitis treated conservatively, previous upper abdominal surgery, right upper quadrant pain, rigidity in right upper abdomen and ultrasonographic parameters - thickening of the gallbladder wall ≥ 4 mm, hydropic gallbladder (diameter exceeding 4.5 cm) and shrunken gallbladder. One point was allocated for each risk factor, except for previous upper abdominal surgery, which scored two. Difficulty of the surgery was assessed by operating time (OT) and the postoperative subjective evaluation score (PSES). Results: Five hundred and eighty-six consecutive patients were enrolled in the prospective observational study. A significant linear correlation was observed between the risk score and measures of difficulty employed. Five levels of difficulty were defined (score 0, 1, 2, 3, ≥ 4) with significant differences in OT, PSES and conversion rates (p < 0.001). Conclusions: The suggested risk score is designed as a simple and reliable predictive model, possibly effective to overcome the negative effect of the individual proficiency gain curve and/or to select 'easy' cases for day surgery, single incision laparoscopic surgery or natural orifice translumenal endoscopic surgery procedures.

Piskova L.,University of Pavol Jozef Safarik | Horvath T.,University of Pavol Jozef Safarik
CEUR Workshop Proceedings | Year: 2013

In this paper, an experimental comparison of publicly available algorithms for computing intents of all formal concepts and mining frequent closed itemsets is provided. Experiments are performed on real data sets from UCI Machine Learning Repository and FIMI Repository. Results of experiments are discussed at the end of the paper. © paper author(s), 2013.

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