Investigation on reconstruction methods applied to 3D terahertz computed tomography

International audience3D terahertz computed tomography has been performed using a monochromatic millimeter wave imaging system coupled with an infrared temperature sensor. Three different reconstruction methods (standard back-projection algorithm and two iterative analysis) have been compared in order to reconstruct large size 3D objects. The quality (intensity, contrast and geometric preservation) of reconstructed cross-sectional images has been discussed together with the optimization of the number of projections. Final demonstration to real-life 3D objects has been processed to illustrate the potential of the reconstruction methods for applied terahertz tomography

Streaming instability of slime mold amoebae: An analytical model

During the aggregation of amoebae of the cellular slime mould Dictyostelium, the interaction of chemical waves of the signaling molecule cAMP with cAMP-directed cell movement causes the breakup of a uniform cell layer into branching patterns of cell streams. Recent numerical and experimental investigations emphasize the pivotal role of the cell-density dependence of the chemical wave speed for the occurrence of the streaming instability. A simple, analytically tractable, model of Dictyostelium aggregation is developed to test this idea. The interaction of cAMP waves with cAMP-directed cell movement is studied in the form of coupled dynamics of wave front geometries and cell density. Comparing the resulting explicit instability criterion and dispersion relation for cell streaming with the previous findings of model simulations and numerical stability analyses, a unifying interpretation of the streaming instability as a cAMP wave-driven chemotactic instability is proposed

Caspase Activation Is Required for T Cell Proliferation

Triggering of Fas (CD95) by its ligand (FasL) rapidly induces cell death via recruitment of the adaptor protein Fas-associated death domain (FADD), resulting in activation of a caspase cascade. It was thus surprising that T lymphocytes deficient in FADD were reported recently to be not only resistant to FasL-mediated apoptosis, but also defective in their proliferative capacity. This finding suggested potentially dual roles of cell growth and death for Fas and possibly other death receptors. We report here that CD3-induced proliferation and interleukin 2 production by human T cells are blocked by inhibitors of caspase activity. This is paralleled by rapid cleavage of caspase-8 after CD3 stimulation, but no detectable processing of caspase-3 during the same interval. The caspase contribution to T cell activation may occur via TCR-mediated upregulation of FasL, as Fas-Fc blocked T cell proliferation, whereas soluble FasL augmented CD3-induced proliferation. These findings extend the role of death receptors to the promotion of T cell growth in a caspase-dependent manner

Metabolomics Study of Urine in Autism Spectrum Disorders Using a Multiplatform Analytical Methodology

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with no clinical biomarker. Aims of this study were to characterize a metabolic signature of ASD, and to evaluate multi-platform analytical methodologies in order to develop predictive tools for diagnosis and disease follow up. Urines were analyzed using: 1H- and 1 H-13C-NMR-based approaches and LC-HRMS-based approaches (ESI+ and ESI- on a HILIC and C18 chromatography column). Data tables obtained from the six analytical modalities on a training set of 46 urines (22 autistic children and 24 controls) were processed by multivariate analysis (OPLS-DA). Prediction of each of these OPLS-DA models were then evaluated using a prediction set of 16 samples (8 autistic children and 8 controls) and ROC curves. Thereafter, a data fusion block-scaling OPLS-DA model was generated from the 6 best models obtained for each modality. This fused OPLSDA model showed an enhanced performance (R 2Y(cum)=0.88, Q 2 (cum)=0.75) compared to each analytical modality model, as well as a better predictive capacity (AUC=0.91, p-value 0.006). Metabolites that are most significantly different between autistic and control children (p<0.05) are indoxyl sulfate, N-\u2329-Acetyl-L-arginine, methyl guanidine and phenylacetylglutamine. This multi-modality approach has the potential to contribute to find robust biomarkers and characterize a metabolic phenotype of the ASD population

Stochastic analysis of three-dimensional hydraulic conductivity upscaling in a heterogeneous tropical soil

[EN] Hydraulic conductivity (K) heterogeneity is seldom considered in geotechnical practice for the impossibility of sampling the entire area of interest and for the difficulty of accounting for scale effects. Stochastic three-dimensional K upscaling can tackle these two problems, and a workflow is described with an application in a tropical soil. The application shows that K heterogeneity can be incorporated in the daily practice of the geotechnical modeler while discussing the aspects to consider when performing the upscaling so that the upscaled models reproduce the average fluxes at the fine scale.The authors thank the financial support by the Brazilian National Council for Scientific and Technological Development (CNPq) (Project 401441/2014-8). The doctoral fellowship award to the first author by the Coordination of Improvement of Higher Level Personnel (CAPES) is gratefully acknowledged. The first author thanks the International Mobility Grant awarded by CNPq (200597/2015-9) and Santander mobility. The authors also thank DHI-WASI for providing a FEFLOW Software license.Almeida De-Godoy, V.; Zuquette, L.; Gómez-Hernández, JJ. (2018). Stochastic analysis of three-dimensional hydraulic conductivity upscaling in a heterogeneous tropical soil. Computers and Geotechnics. 100:174-187. https://doi.org/10.1016/j.compgeo.2018.03.004S17418710

Geostatistical analysis of an experimental stratigraphy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95276/1/wrcr10212.pd

Galectin-9 Controls CD40 Signaling through a Tim-3 Independent Mechanism and Redirects the Cytokine Profile of Pathogenic T Cells in Autoimmunity

While it has long been understood that CD40 plays a critical role in the etiology of autoimmunity, glycobiology is emerging as an important contributor. CD40 signaling is also gaining further interest in transplantation and cancer therapies. Work on CD40 signaling has focused on signaling outcomes and blocking of its ligand, CD154, while little is known about the actual receptor itself and its control. We demonstrated that CD40 is in fact several receptors occurring as constellations of differentially glycosylated forms of the protein that can sometimes form hybrid receptors with other proteins. An enticing area of autoimmunity is differential glycosylation of immune molecules leading to altered signaling. Galectins interact with carbohydrates on proteins to effect such signaling alterations. Studying autoimmune prone NOD and non-autoimmune BALB/c mice, here we reveal that in-vivo CD40 signals alter the glycosylation status of non-autoimmune derived CD4 T cells to resemble that of autoimmune derived CD4 T cells. Galectin-9 interacts with CD40 and, at higher concentrations, prevents CD40 induced proliferative responses of CD4loCD40+ effector T cells and induces cell death through a Tim-3 independent mechanism. Interestingly, galectin-9, at lower concentrations, alters the surface expression of CD3, CD4, and TCR, regulating access to those molecules and thereby redirects the inflammatory cytokine phenotype and CD3 induced proliferation of autoimmune CD4loCD40+ T cells. Understanding the dynamics of the CD40 receptor(s) and the impact of glycosylation status in immunity will gain insight into how to maintain useful CD40 signals while shutting down detrimental ones