2,122 research outputs found
Community Deception in Networks: Where We Are and Where We Should Go
No full textCommunity deception tackles the following problem: given a target community C inside a network G and a budget of updates β (e.g., edge removal and additions), what is the best way (i.e., optimization of some function φG(C)) to perform such updates in a way that C can escape to a detector D (i.e., a community detection algorithm)? This paper aims at: (i) presenting an analysis of the state-of-the-art deception techniques; (ii) evaluating state-of-the-art deception techniques: (iii) making available a library of techniques to practitioners and researchers
Invecchiamento, stress ed ipertensione. 101° Congresso Nazionale Società Italiana di Medicina Interna, Torino 18-22 Novembre 2000
No full textHyperthermia enhances CD95-ligand gene expression in T lymphocytes
No full textHyperthermia represents an interesting therapeutic strategy for the treatment of tumors. Moreover, it is able to regulate several aspects of the immune response. Fas (APO-1/CD95) and its ligand (FasL) are cell surface proteins whose interaction activates apoptosis of Fas-expressing targets. In T cells, the Fas-Fas-L system regulates activation-induced cell death, is implicated in diseases in which lymphocyte homeostasis is compromised, and plays an important role during cytotoxic and regulatory actions mediated by these cells. In this study we describe the effect of hyperthermia on activation of the fas-L gene in T lymphocytes. We show that hyperthermic treatment enhances Fas-L-mediated cytotoxicity,fas-L mRNA expression, and fas-L promoter activity in activated T cell lines. Our data indicate that hyperthermia enhances the transcriptional activity of AP-1 and NF-kappaB in activated T cells, and this correlates with an increased expression/nuclear translocation of these transcription factors. Moreover, we found that heat shock factor-1 is a transactivator of fas-L promoter in activated T cells, and the overexpression of a dominant negative form of heat shock factor-1 may attenuate the effect of hyperthermia on fas-L promoter activity. Furthermore, overexpression of dominant negative mutants of protein kinase Cepsilon (PKCepsilon) and PKCtheta partially inhibited the promoter activation and, more importantly, could significantly reduce the enhancement mediated by hyperthermia, indicating that modulation of PKC activity may play an important role in this regulation. These results add novel information on the immunomodulatory action of heat, in particular in the context of its possible use as an adjuvant therapeutic strategy to consider for the treatment of cancer
First measurement of prompt and non-prompt D*+ vector meson spin alignment in pp collisions at √s=13 Tev
No full textThis letter reports the first measurement of spin alignment, with respect to the helicity axis, for D⁎+ vector mesons and their charge conjugates from charm-quark hadronisation (prompt) and from beauty-meson decays (non-prompt) in hadron collisions. The measurements were performed at midrapidity (|y|<0.8) as a function of transverse momentum (pT) in proton–proton (pp) collisions collected by ALICE at the centre-of-mass energy s=13TeV. The diagonal spin density matrix element ρ00 of D⁎+ mesons was measured from the angular distribution of the D⁎+→D0(→K−π+)π+ decay products, in the D⁎+ rest frame, with respect to the D⁎+ momentum direction in the pp centre of mass frame. The ρ00 value for prompt D⁎+ mesons is consistent with 1/3, which implies no spin alignment. However, for non-prompt D⁎+ mesons an evidence of ρ00 larger than 1/3 is found. The measured value of the spin density element is ρ00=0.455±0.022(stat.)±0.035(syst.) in the 5<20GeV/c interval, which is consistent with a PYTHIA 8 Monte Carlo simulation coupled with the EVTGEN package, which implements the helicity conservation in the decay of D⁎+ meson from beauty mesons. In non-central heavy-ion collisions, the spin of the D⁎+ mesons may be globally aligned with the direction of the initial angular momentum and magnetic field. Based on the results for pp collisions reported in this letter it is shown that alignment of non-prompt D⁎+ mesons due to the helicity conservation coupled to the collective anisotropic expansion may mimic the signal of global spin alignment in heavy-ion collisions
Explaining graph navigational queries
No full textGraph navigational languages allow to specify pairs of nodes in a graph subject to the existence of paths satisfying a certain regular expression. Under this evaluation semantics, connectivity information in terms of intermediate nodes/edges that contributed to the answer is lost. The goal of this paper is to introduce the GeL language, which provides query evaluation semantics able to also capture connectivity information and output graphs. We show how this is useful to produce query explanations. We present efficient algorithms to produce explanations and discuss their complexity. GeL machineries are made available into existing SPARQL processors thanks to a translation from GeL queries into CONSTRUCT SPARQL queries. We outline examples of explanations obtained with a tool implementing our framework and report on an experimental evaluation that investigates the overhead of producing explanations
Hyperthermia enhances CD95-ligand gene expression in T lymphocytes
No full textHyperthermia represents an interesting therapeutic strategy for the treatment of tumors. Moreover, it is able to regulate several aspects of the immune response. Fas (APO-1/CD95) and its ligand (FasL) are cell surface proteins whose interaction activates apoptosis of Fas-expressing targets. In T cells, the Fas-Fas-L system regulates activation-induced cell death, is implicated in diseases in which lymphocyte homeostasis is compromised, and plays an important role during cytotoxic and regulatory actions mediated by these cells. In this study we describe the effect of hyperthermia on activation of the fas-L gene in T lymphocytes. We show that hyperthermic treatment enhances Fas-L-mediated cytotoxicity, fas-L mRNA expression, and fas-L promoter activity in activated T cell lines. Our data indicate that hyperthermia enhances the transcriptional activity of AP-1 and NF-κB in activated T cells, and this correlates with an increased expression/nuclear translocation of these transcription factors. Moreover, we found that heat shock factor-1 is a transactivator of fas-L promoter in activated T cells, and the overexpression of a dominant negative form of heat shock factor-1 may attenuate the effect of hyperthermia on fas-L promoter activity. Furthermore, overexpression of dominant negative mutants of protein kinase Cε (PKCε) and PKCθ partially inhibited the promoter activation and, more importantly, could significantly reduce the enhancement mediated by hyperthermia, indicating that modulation of PKC activity may play an important role in this regulation. These results add novel information on the immunomodulatory action of heat, in particular in the context of its possible use as an adjuvant therapeutic strategy to consider for the treatment of cancer
Negative regulation of CD95-ligand gene expression by vitamin D3 in T lymphocytes.
No full textFas (APO-1/CD95) and its ligand (FasL/CD95L) are cell surface proteins whose interaction activates apoptosis of Fas-expressing targets. In T lymphocytes, the Fas/FasL system regulates activation-induced cell death, a fundamental mechanism for negative selection of immature T cells in the thymus and for maintenance of peripheral tolerance. Aberrant expression of Fas and FasL has also been implicated in diseases in which the lymphocyte homeostasis is compromised, and several studies have described the pathogenic functions of Fas and FasL in vivo, particularly in the induction/regulation of organ-specific autoimmune diseases. The 1,25(OH)(2)D-3 is a secosteroid hormone that activates the nuclear receptor vitamin D-3 receptor (VDR), whose immunosuppressive activities have been well studied in different models of autoimmune disease and in experimental organ transplantation. We and others have recently described the molecular mechanisms responsible for the negative regulation of the IFN-gamma and IL-12 genes by 1,25(OH)(2)D-3 in activated T lymphocytes and macrophages/dendritic cells. In this study, we describe the effect of 1,25(OH)(2)D-3 on the activation of the fasL gene in T lymphocytes. We show that 1,25(OH),D3 inhibits activation-induced cell death, fasL mRNA expression, and that 1,25(OH)(2)D-3-activated VDR represses fasL promoter activity by a mechanism dependent on the presence of a functional VDR DNA-binding domain and ligand-dependent transcriptional activation domain (AF-2). Moreover, we identified a minimal region of the promoter containing the transcription start site and a noncanonical c-Myc-binding element, which mediates this repression. These results place FasL as a novel target for the immunoregulatory activities of 1,25(OH)(2)D-3, and confirm the interest for a possible pharmacological use of this molecule and its derivatives
Measurement of the non-prompt D-meson fraction as a function of multiplicity in proton-proton collisions at √s=13 TeV
No full textThe fractions of non-prompt (i.e. originating from beauty-hadron decays) D0 and D+ mesons with respect to the inclusive yield are measured as a function of the charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of s = 13 TeV with the ALICE detector at the LHC. The results are reported in intervals of transverse momentum (p T) and integrated in the range 1 < p T < 24 GeV/c. The fraction of non-prompt D0 and D+ mesons is found to increase slightly as a function of p T in all the measured multiplicity intervals, while no significant dependence on the charged-particle multiplicity is observed. In order to investigate the production and hadronisation mechanisms of charm and beauty quarks, the results are compared to PYTHIA 8 as well as EPOS 3 and EPOS 4 Monte Carlo simulations, and to calculations based on the colour glass condensate including three-pomeron fusion
Maximizing the spread of an opinion when tertium datur est
No full textOpinion diffusion has been largely studied in the literature on settings where the opinion whose spread has to be maximized, say white, competes against one opinion only, say black For instance, for diffusion mechanisms modeled in terms of best response dynamics over majority agents (who change their opinion as to conform it to the majority of their neighbors), it is known that the spread can be maximized via certain greedy dynamics that can be computed in polynomial time This setting is precisely the one considered in the paper However, differently from earlier literature, it is assumed that one further opinion, say gray, is available to the agents Moving from the observation that, with the third alternative to hand, greedy dynamics can dramatically fail to maximize the spread of opinion white, the paper then embarks in thorough computational, algorithmic and experimental studies The picture that emerges is totally different from what is known for the case when two opinions are available only indeed, it is shown that greedy dynamics can dramatically fail in maximizing the spread In particular, deciding whether there exists a dynamics that can spread the opinion white to at least k agents or can reach a consensus is shown to be intractable, formally NP-hard On the other hand, islands of tractability based on certain structural properties of the interaction graph are identified Finally, experimental results are discussed, which shed lights on opinion diffusion in real social networks
A technique to search functional similarities in PPI networks
No full textWe describe a method to search for similarities across protein-protein interaction networks of different organisms. The technique core consists in computing a maximum weight matching of bipartite graphs resulting from comparing the neighbourhoods of proteins belonging to different networks. Both quantitative and reliability information are exploited. We tested the method on the networks of S. cerevisiae, D. melanogaster and C. elegans. The experiments showed that the technique is able to detect functional orthologs when the sole sequence similarity does not prove itself sufficient. They also demonstrated the capability of our approach in discovering common biological processes involving uncharacterised proteins
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