Test of preemptive real-time systems

Time Petri nets with stopwatches not only model system/environment interactions and time constraints. They further enable modeling of suspend/resume operations in real-time systems. Assuming the modelled systems are non deterministic and partially observable, the paper proposes a test generation approach which implements an online testing policy and outputs test results that are valid for the (part of the) selected environment. A relativized conformance relation named rswtioco is defined and a test generation algorithm is presented. The proposed approach is illustrated on an example

Graphical matroid for causality assignment in bond graphs

AbstractGraphical methods provide useful tools to study the structure of systems. The bond-graph approach is used in modelling process of dynamical systems. The matroid theory offers a powerful tool if we are interested in combinatorial aspects of causality assignment. This paper is organized as follows: after an introduction, Section 2 introduces some matroid background, and Section 3 presents some matroid definitions about structural properties. In Section 4, the main result of this paper is the proposal of a procedure that constructs cycle and co-cycle graphs from graphical matroids defined in the previous section. Validity of this procedure and some examples are shown in Sections 5 and 6, respectively, and concluding remarks are given in Section 7

New dicationic piperidinium hexafluorophosphate ILs, synthesis, characterization and dielectric measurements

AbstractA new class of dicationic ionic liquids (ILs) were synthesized for electrochemical applications at high temperatures. The syntheses are based on a dialkylation reaction of N-alkylpiperidine followed by anion exchange. The structures of ILs, based on piperidinium combined with hexafluorophosphate anion, were identified by using 1H, 13C, 19F, 31P NMR and FT-IR spectroscopy. ILs’ thermal properties were investigated in the temperature range from −50 to 350°C by using differential scanning calorimetry (DSC). In the frequency of 10−2–106Hz range, dielectric measurements were performed on ILs’ samples at various temperatures from −80 to 20°C, i.e. around the glass transition temperature. The peak relaxation was observed near to this temperature. Also, the conductivity was investigated and the energy activation determined. The temperature dependence of the relaxation times was shown to be governed by the Arrhenius equation

HIV viraemic patients downregulate CD94/NKG2A inhibitory receptors on NK as well as CD8 T cells in comparison with aviraemic counterparts

Background: The CD94/NKG2 heterodimer is a C-type lectin receptor formed by the association of CD94 and one of the NKG2 molecules (namely NKG2A, -B, -C or –E). The interaction of CD94/NKG2A with non classical HLA-E molecules delivers inhibitory signals. CD94/NKG2A is normally expressed on most NK cells whereas less than 5% of peripheral resting CD8+ T cells are positive. Although several reports have clearly shown an upregulation of CD94 on CD8 T cells in HIV infection, the simultaneous expression of both subunits of the inhibitory receptor on NK and T cells and its relation with viral load is largely unknown. Methods: PBLs from 30 HIV-infected patients (16 viraemic and 14 aviraemic under HAART) and 18 healthy volunteers were analysed by flow cytometry after staining with the following monoclonal antibodies (Percp-conjugated anti-CD8, FITC-conjugated anti-CD3, APC-conjugated anti-CD94, PE-conjugated anti-NKG2A). Results: The proportion of CD8 T cells expressing the CD94/NKG2A inhibitory receptor was not significantly increased in HIV-infected patients (5.68 ± 3.72%) in comparison with non-infected controls (4.90±2.84%). Interestingly, patients with viral load < 50 copies/ml had a higher proportion of CD8 T cells expressing the inhibitory receptor (7.15 ± 3.63%) than patients with HIV viraemia (4.40 ± 3.40%), p= 0.041. The same pattern was observed for NK cells and was even more pronounced. In aviraemic individuals, 61.75 ± 20.39% of NK cells expressed the inhibitory receptor vs 42.88 ± 26.38% in viraemic patients. The proportion of CD94/NKG2A positive cells was correlated between NK and CD8 T cell subsets (p=0.0351) but there was no correlation with absolute or relative CD4 counts. Conclusions: Our results suggest that chronic stimulation with HIV antigens in viraemic patients could lead to decreased rather than increased expression of inhibitory receptors on NK and CD8 T cells. This could contribute to the abnormal activation of the immune system associated with advanced HIV disease

1,3-dipolar cycloadditions of aldehydes or Imines with carbonyl ylides generated from epoxides: Classical heating and microwave irradiation

International audienceCycloadditions of aldehydes with carbonyl ylides to give dioxolanes have been carried out without solvent under microwave irradiation. The reactions proceeded in similar yields and stereoselectivities, but in shorter reaction times, than those obtained in toluene at reflux using an oil bath. Cycloadditions conducted between imines and carbonyl ylides using the same protocol were less efficient because the oxazolidines formed proved unstable under the reaction conditions

Synthesis, X-ray crystal structures, electrochemistry and theoretical investigation of a tetradentate nickel and copper Schiff base complexes

International audienceNew tetradentate mononuclear nickel(II) [NiL] and pentadentate binuclear copper(II) [Cu 2 L 2 H 2 O], H 2 O Schiff base complexes have been synthesized. The crystal structures of [NiL] and [Cu 2 L 2 H 2 O], H 2 O have been determined by X-ray diffraction method showing distorted square-planar geometry for [NiL] and distorted tetragonal pyramid geometry for [Cu 2 L 2 H 2 O], H 2 O. In both complexes, the dehydroacetic acid functional group engages in a deprotonated manner and coordination occurs through the nitrogen atoms of the imine function and the phenolic oxygen. Density Functional Theory calculations are carried out for the determination of the optimized structures. The fundamental vibrational wave numbers are calculated and a good agreement between observed and calculated wave numbers is achieved

Downregulation of CD94/NKG2A inhibitory receptors on CD8+ T cells in HIV infection is more pronounced in subjects with detected viral load than in their aviraemic counterparts

The CD94/NKG2A heterodimer is a natural killer receptor (NKR), which inhibits cell-mediated cytotoxicity upon interaction with MHC class I gene products. It is expressed by NK cells and by a small fraction of activated CD8+ T lymphocytes. Abnormal upregulation of the CD94/NKG2A inhibitory NKR on cytotoxic T cells (CTLs) could be responsible for a failure of immunosurveillance in cancer or HIV infection. In this study, CD94/NKG2A receptor expression on CD8+ T lymphocytes and NK cells was assessed in 46 HIV-1-infected patients (24 viraemic, 22 aviraemic) and 10 healthy volunteers. The percentage of CD8+ T lymphocytes expressing the CD94/NKG2A inhibitory heterodimer was very significantly decreased in HIV-1-infected patients in comparison with non-infected controls. Within the HIV infected patients, the proportion of CD8+ T lymphocytes and NK cells expressing CD94/NKG2A was higher in subjects with undetectable viral loads in comparison with their viraemic counterparts. No significant difference was detected in the proportion of CD8+ T lymphocytes expressing the activatory CD94/NKG2C heterodimer between the HIV-1 infected patients and the healthy donors, nor between the vireamic and avireamic HIV-1 infected patients. In conclusion, chronic stimulation with HIV antigens in viraemic patients leads to a decreased rather than increased CD94/NKG2A expression on CD8+ T lymphocytes and NK cells

Effects of C(2) Methylation on Thermal Behavior and Interionic Interactions in Imidazolium-Based Ionic Liquids with Highly Symmetric Anions

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