Temporal relation algebra for audiovisual content analysis

Multimedia Tools and Applications - The context of this work is to characterize the content and the structure of audiovisual documents by analysing the temporal relationships between basic events...     

Influence of pressurised cryogenic nitrogen technology on Arthrospira platensis (spirulina) preservation during storage

In this study, preservation of spirulina using the new pressurised cryogenic nitrogen technology (PCN) was compared to classical methods used in laboratories and industry. Spirulina morphology was better preserved by PCN compared to unpressurised cryogeny and classical freezing at −20 °C that led to cells fragmentation. A 25% loss of Phycocyanin-C content against 60% were measured after 98 days storage for 6-Bar PCN process and frozen samples, respectively. The Total AntiOxidant Power (PAOT Liquid Technology^®) was used for determination of total antioxidant and oxidant power of spirulina extracts. PAOT value of PCN samples was 50% higher than the frozen sample. From ABTS measurements on PCN spirulina fractions sonicated or not, it was suggested that pressurisation at 6 bars allowed a better preservation of free antioxidants (outside the cells) due to replacement of oxygen by nitrogen in the frozen beads. After dehydration, phycocyanin-C content variation during storage at 20 °C and 33% RH showed higher loss for freeze-dried spirulina treated at 0 compared to 6 Bars.     

MicroRNA Profiling of B Cell Subsets from Systemic Lupus Erythematosus Patients Reveals Promising Novel Biomarkers

MicroRNAs control the differentiation and function of B cells, which are considered key elements in the pathogenesis of systemic lupus erythematosus (SLE). However, a common micro(mi)RNA signature has not emerged since published data includes patients of variable ethnic background, type of disease, and organ involvement, as well as heterogeneous cell populations. Here, we aimed at identifying a miRNA signature of purified B cells from renal and non-renal severe SLE patients of Latin American background, a population known to express severe disease. Genome-wide miRNA expression analyses were performed on naive and memory B cells and revealed two categories of miRNA signatures. The first signature represents B cell subset-specific miRNAs deregulated in SLE: 11 and six miRNAs discriminating naive and memory B cells of SLE patients from healthy controls (HC), respectively. Whether the miRNA was up or down-regulated in memory B cells as compared with naive B cells in HC, this difference was abolished in SLE patients, and vice versa. The second signature identifies six miRNAs associated with specific pathologic features affecting renal outcome, providing a further understanding for SLE pathogenesis. Overall, the present work provided promising biomarkers in molecular diagnostics for disease severity as well as potential new targets for therapeutic intervention in SLE.     

Impregnation of Composite Materials: a Numerical Study

Oxide ceramic matrix composites are currently being developed for aerospace applications such as the exhaust, where the parts are subject to moderately high temperatures (≈?700 ^°C) and oxidation. These composite materials are normally formed by, among other steps, impregnating a ceramic fabric with a slurry of ceramic particles. This impregnation process can be complex, with voids possibly forming in the fabric depending on the process parameters and material properties. Unwanted voids or macroporosity within the fabric can decrease the mechanical properties of the parts. In order to design an efficient manufacturing process able to impregnate the fabric well, numerical simulations may be used to design the process as well as the slurry. In this context, a tool is created for modeling different processes. Thétis, which solves the Navier-Stokes-Darcy-Brinkman equation using finite volumes, is expanded to take into account capillary pressures on the mesoscale. This formulation allows for more representativity than for Darcy’s law (homogeneous preform) simulations while avoiding the prohibitive simulation times of a full discretization for the composing fibers at the representative elementary volume scale. The resulting tool is first used to investigate the effect of varying the slurry parameters on impregnation evolution. Two different processes, open bath impregnation and wet lay-up, are then studied with emphasis on varying their input parameters (e.g. inlet velocity).     

Microscopic investigation of the formation of a thermoset wheat gluten network in a model system relevant for bread making

Although the impact of heat on molecular properties of wheat gluten is well understood, changes in its microstructure have rarely been studied. Here, formation of the thermoset gluten network in a model system relevant for bread baking was studied with confocal laser scanning microscopy and protein network analysis. From 65 °C onwards, gluten converts from thick aligned protein strands in a highly branched and homogeneous network of small thin protein threads. Neither gliadin incorporation in the network nor application of aqualysin 1, the thermo-active serine peptidase from Thermus aquaticus which recently has been reported to hydrolyse gluten proteins in dough only at temperatures exceeding 80 °C, impacts on the gluten microstructure. As starch causes structure setting itself and thereby decreases protein mobility, molecular scale changes in the gluten network at temperatures exceeding 80 °C brought about by aqualysin 1 do not impact its microstructure.     

Partial Sperm beta1 Integrin Subunit Deletion Proves Its Involvement in Mouse Gamete Adhesion/Fusion

We have previously shown, using antibodies, that the sperm alpha6beta1 integrin is involved in mouse gamete fusion in vitro. Here we report the conditional knockdown of the sperm Itgb1 gene. It induced a drastic failure of sperm fusogenic ability with sperm accumulation in the perivitelline space of in vitro inseminated oocytes deleted or not for the Itgb1 gene. These data demonstrate that sperm, but not oocyte, beta1 integrin subunit is involved in gamete adhesion/fusion. Curiously, knockdown males were fertile in vivo probably because of the incomplete Cre-mediated deletion of the sperm Itgb1 floxed gene. Indeed, this was shown by Western blot analysis and confirmed by both the viability and litter size of pups obtained by mating partially sperm Itgb1 deleted males with females producing completely deleted Itgb1 oocytes. Because of the total peri-implantation lethality of Itgb1 deletion in mice, we assume that sperm that escaped the Itgb1 excision seemed to be preferentially used to fertilize in vivo. Here, we showed for the first time that the deletion, even partial, of the sperm Itgb1 gene makes the sperm unable to normally fertilize oocytes. However, to elucidate the question of the essentiality of its role during fertilization, further investigations using a mouse expressing a recombinase more effective in male germ cells are necessary.     

Long-term monitoring of natural hydrogen superficial emissions in a brazilian cratonic environment. Sporadic large pulses versus daily periodic emissions

In many basins, hydrogen-emitting structures are now observed, but the estimation of the H₂ flow leading to their formation remains poorly constrained since all data show that the H₂ emissions are variable in space and time. We present here the data of a long-term monitoring campaign with a high density of permanent hydrogen detectors installed in 2 structures in the Minas Gerais State (Brazil). Results show that two kinds of signals are recorded, large sporadic pulses that affect the H₂ content of the soil for one or two days and smaller ones, with a daily periodicity, that last 6 h and during which the near surface soil concentration usually does not exceed 200 ppm. This last signal is very regular in frequency, less in amount, and the daily maximum happens around noon or in the early afternoon. We interpret the large pulses as evidences of a deep hydrogen flux, leaking either from a reservoir located in the subsurface, from an aquifer which is degassing or, although it seems unlikely, directly from the H₂ generation area.The time correlation between the pulse and the increase of the daily signal suggests that this last one corresponds to the slow release of the gas that has been captured by the soil during its transport towards the surface. This daily signal is most likely influenced by external factors such as atmospheric pressure and sub-surface bacterial activity. In map view, the lack of correlation between the highest hydrogen concentrations over time suggests that the soil is very heterogeneous and that preferential pathways exist. The results confirm that long-term monitoring, over a few months, is mandatory to catch a certain number of high pulses and so to have a better estimation of the real flow. Data also suggests that sensors with a large concentration range should be used (from 10 to several 10⁴ ppm). Even if quantification of leakage doesn't help to quantify the subsurface reserves, these new data allow a more precise evaluation of the quantity of H₂ released in surface by these structures, few hundred of kilo per day, and confirm the high H₂ prospectivity of this basin.