Experimental and Numerical Investigation on the Irregularity of Carbonation Depth of Concrete Under Supercritical Condition

The heterogeneity of a cement-based material results in a random spatial distribution of carbonation depth, which may significantly affect the mechanical properties and durability of the material. Currently, there is a lack of both experimental and numerical investigations aiming at a statistical understanding of this important phenomenon. This paper presents both experimental and numerical supercritical carbonation test results of concrete blocks. The random fields of porosity and two-dimension random aggregate model of concrete were proposed for the simulation. The carbonation depths are measured and distributed along the carbonation boundary by the proposed rapid image processing technique, which are then statistically studied. The study has shown that considering the random distribution of coarse aggregates and using a random field of porosity with due consideration of spatial correlation and variance, the irregularity of carbonation depth can be realistically captured by the numerical model. Overall the methodology adopted in the paper can provide a foundation for future investigations on probability analysis of carbonation depth and other similar work based on multi-scale and –physics modelling

Ionic effect on combing of single DNA molecules and observation of their force-induced melting by fluorescence microscopy

Molecular combing is a powerful and simple method for aligning DNA molecules onto a surface. Using this technique combined with fluorescence microscopy, we observed that the length of lambda-DNA molecules was extended to about 1.6 times their contour length (unextended length, 16.2 micrometers) by the combing method on hydrophobic polymethylmetacrylate (PMMA) coated surfaces. The effects of sodium and magnesium ions and pH of the DNA solution were investigated. Interestingly, we observed force-induced melting of single DNA molecules.Comment: 12 page

Undetectable quantum transfer through a continuum

We demonstrate that a quantum particle, initially prepared in a quantum well, can propagate through a reservoir with a continuous spectrum and reappear in a distant well without being registered in the reservoir. It is shown that such a passage through the reservoir takes place even if the latter is {\em continuously} monitored. We discuss a possible experimental realization of such a teleportation phenomenon in mesoscopic systems.Comment: 8 pages, 6 figures, revised version, Phys. Lett. A, in pres

Validation of Sentinel-2, MODIS, CGLS, SAF, GLASS and C3S leaf area index products in maize crops

Altres ajuts: this research was funded by the Copernicus Global Land Service (CGLOPS-1, 199494-JRC).We proposed a direct approach to validate hectometric and kilometric resolution leaf area index (LAI) products that involved the scaling up of field-measured LAI via the validation and recalibration of the decametric Sentinel-2 LAI product. We applied it over a test study area of maize crops in northern China using continuous field measurements of LAINet along the year 2019. Sentinel-2 LAI showed an overall accuracy of 0.67 in terms of Root Mean Square Error (RMSE) and it was used, after recalibration, as a benchmark to validate six coarse resolution LAI products: MODIS, Copernicus Global Land Service 1 km Version 2 (called GEOV2) and 300 m (GEOV3), Satellite Application Facility EUMETSAT Polar System (SAF EPS) 1.1 km, Global LAnd Surface Satellite (GLASS) 500 m and Copernicus Climate Change Service (C3S) 1 km V2. GEOV2, GEOV3 and MODIS showed a good agreement with reference LAI in terms of magnitude (RMSE ≤ 0.29) and phenology. SAF EPS (RMSE = 0.68) and C3S V2 (RMSE = 0.41), on the opposite, systematically underestimated high LAI values and showed systematic differences for phenological metrics: a delay of 6 days (d), 20 d and 24 d for the start, peak and the end of growing season, respectively, for SAF EPS and an advance of −4 d, −6 d and −6 d for C3S

Angiogenic deficiency and adipose tissue dysfunction are associated with macrophage malfunction in SIRT1 \u3csup\u3e-/-\u3c/sup\u3e mice

The histone deacetylase sirtuin 1 (SIRT1) inhibits adipocyte differentiation and suppresses inflammation by targeting the transcription factors peroxisome proliferator-activated receptor γ and nuclear factor κB. Although this suggests that adiposity and inflammation should be enhanced when SIRT1 activity is inactivated in the body, this hypothesis has not been tested in SIRT1 null (SIRT1 -/-) mice. In this study, we addressed this issue by investigating the adipose tissue in SIRT1 -/-mice. Compared with their wild-type littermates, SIRT1 null mice exhibited a significant reduction in body weight. In adipose tissue, the average size of adipocytes was smaller, the content of extracellular matrix was lower, adiponectin and leptin were expressed at 60% of normal level, and adipocyte differentiation was reduced. All of these changes were observed with a 50% reduction in capillary density that was determined using a three-dimensional imaging technique. Except for vascular endothelial growth factor, the expression of several angiogenic factors (Pdgf, Hgf, endothelin, apelin, and Tgf-β)was reduced by about 50%. Macrophage infiltration and inflammatory cytokine expression were 70% less in the adipose tissue of null mice and macrophage differentiation was significantly inhibited in SIRT1 -/- mouse embryonic fibroblasts in vitro. In wild-type mice, macrophage deletion led to a reduction in vascular density. These data suggest that SIRT1 controls adipose tissue function through regulation of angiogenesis, whose deficiency is associated with macrophage malfunction in SIRT1 -/- mice. The study supports the concept that inflammation regulates angiogenesis in the adipose tissue. Copyright © 2012 by The Endocrine Society