Model for the Patterns of Salt-Spray-Induced Chloride Corrosion in Concretes under Coupling Action of Cyclic Loading and Salt Spray Corrosion

In this study, the patterns of chloride ion erosion of unsaturated concrete subjected to the coupling action of cyclic loading and salt spray corrosion were experimentally studied, and Fick’s Second Law was used to fit the variation patterns of chloride concentration to obtain the chloride diffusion coefficient. Accordingly, we have established a mathematical model that describes chloride transport in unsaturated concrete and accounts for the effects of gas flow, water migration, convection diffusion, and capillary action. This model is composed of three equations—the gas flow equation, the solution flow equation, and the solute convection⁻diffusion equation. The COMSOL numerical analysis software was subsequently used to obtain solutions for this model, based on parameters such as porosity and the chloride diffusion coefficient. Subsequently, the saturation, relative permeability, and the chloride ion concentration during the first corrosion cycle were analyzed. The numerical results were consistent with the experimental values and were therefore superior to the values obtained using Fick’s Second Law

Meso-structure and fracture mechanism of mudstone at high temperature

The meso-structure mineral composition and fracture mechanism of uniaxial compressed mudstone samples at high temperature were analyzed by XRD and scanning electron microscopy. The effect of temperature on mudstone composition and fracture mechanism were studied from a meso-structural perspective, and the relationship between meso-structure and macro-mechanical characteristics at high temperature was revealed. The findings demonstrated that the fluctuation in diffraction intensity of kaolinite in the mudstone caused the fluctuation in its mechanical properties. The overall structure underwent a phase change around 600 °C, which led to the sudden change in the mechanical properties of mudstone samples. When the temperature reached 600 °C, the crystalline state worsened and kaolinite disappeared; however, some illite was produced, indicating that the chemical reaction of the structure and sudden drop of bearing capacity of the mudstone. Mudstone fracturing at high temperature involves mainly intergranular and transgranular fractures, which are typical in micro-brittle tensile failure. Considering the macro-fracture characteristics of mudstone, the results suggested that macro-fracture under external force corresponds to the meso-fracture. Keywords: Mudstone, Mineral composition, SEM, Meso-fracture, Macro-fractur

Structural abnormalities in early Tourette syndrome children: a combined voxel-based morphometry and tract-based spatial statistics study.

Tourette Syndrome (TS) is characterized with chronic motor and vocal tics beginning in childhood. Abnormality of both gray (GM) and white matter (WM) has been observed in cortico-striato-thalamo-cortical circuits and sensory-motor cortex of adult TS patient. It is not clear if these morphological changes are also present in TS children and if there are any microstructural changes of WM. To understand the developmental cause of such changes, we investigated volumetric changes of GM and WM using VBM and microstructural changes of WM using DTI, and correlated these changes with tic severity and duration. T1 images and Diffusion Tensor Images (DTI) from 21 TS children were compared with 20 age and gender matched health control children using a 1.5T Philips scanner. All of the 21 TS children met the DSM-IV-TR criteria. T1 images were analyzed using DARTEL-VBM in conjunction with statistical parametric mapping (SPM). Diffusion tensor imaging (DTI) analysis was performed using Tract-Based Spatial Statistics (TBSS). Brain volume changes were found in left superior temporal gyrus, left and right paracentral gyrus, right precuneous cortex, right pre- and post-central gyrus, left temporal occipital fusiform cortex, right frontal pole, and left lingual gyrus. Significant axial diffusivity (AD) and mean diffusivity (MD) increases were found in anterior thalamic radiation, right cingulum bundle projecting to the cingulate gurus and forceps minor. Decreases in white matter volume (WMV) in the right frontal pole were inversely related with tic severity (YGTSS), and increases in AD and MD were positively correlated with tic severity and duration, respectively. These changes in TS children can be interpreted as signs of neural plasticity in response to the experiential demand. Our findings may suggest that the morphological and microstructural measurements from structural MRI and DTI can potentially be used as a biomarker of the pathophysiologic pattern of early TS children

The Receptor-Like Kinase ERECTA Confers Improved Water Use Efficiency and Drought Tolerance to Poplar via Modulating Stomatal Density

Poplar is one of the most important tree species in the north temperate zone, but poplar plantations are quite water intensive. We report here that CaMV 35S promoter-driven overexpression of the PdERECTA gene, which is a member of the LRR-RLKs family from Populus nigra × (Populus deltoides × Populus nigra), improves water use efficiency and enhances drought tolerance in triploid white poplar. PdERECTA localizes to the plasma membrane. Overexpression plants showed lower stomatal density and larger stomatal size. The abaxial stomatal density was 24–34% lower and the stomatal size was 12–14% larger in overexpression lines. Reduced stomatal density led to a sharp restriction of transpiration, which was about 18–35% lower than the control line, and instantaneous water use efficiency was around 14–63% higher in overexpression lines under different conditions. These phenotypic changes led to increased drought tolerance. PdERECTA overexpression plants not only survived longer after stopping watering but also performed better when supplied with limited water, as they had better physical and photosynthesis conditions, faster growth rate, and higher biomass accumulation. Taken together, our data suggest that PdERECTA can alter the development pattern of stomata to reduce stomatal density, which then restricts water consumption, conferring enhanced drought tolerance to poplar. This makes PdERECTA trees promising candidates for establishing more water use efficient plantations

Correlation analysis results of DTI.

<p>(A) Significant correlation between YGTSS and mean AD value (Right anterior thalamic radiation: r = 0.531, p = 0.019. Right cingulum bundle projecting to the cingulate gyrus: r = 0.546, p = 0.016). (B) Significant correlation between tics duration and mean AD value (left anterior thalamic radiation: r = 0.554, p = 0.014. Right anterior thalamic radiation: r = 0.584, p = 0.007. Forceps minor: r = 0.682, p = 0.001). (C) Significant correlation between tics duration and mean MD value (Right anterior thalamic radiation: r = 0.508, p = 0.026. Forceps minor: r = 0.593, p = 0.007).</p

The identified AD skeleton clusters at p < 0.05 (corrected for multiple comparisons) were filled (using tbss_fill script implemented in FSL) to make the presentation easy.

<p>Changes can be found in different brain areas. The white-matter microstructure is altered in the anterior limb of the internal capsule, the corpus callosum and long association fibers such as the inferior longitudinal fascicle. The background image is the standard MNI_T1_1mm template and the FA skeleton (green). Red-Yellow voxels represent regions in which AD was increased significantly in Tourette syndrome patients relative to healthy controls. Axial slices from Z = -20 to 38 in MNI coordinate are shown.</p

Brain areas with regional gray matter or white volume changes.

<p>(A) Reduced regional gray matter volumes (GMV) in left superior temporal gyrus. (B) Increased GMV in left and right precentral gyrus. (C) Reduced regional white matter volumes (WMV) in right precuneous cortex, right precentral gyrus, left temporal occipital fusiform cortex, right frontal pole, right postcentral gyrus and left lingual gyrus. Correlation between volume and YGTSS in right frontal pole (Lower right): r = -0.611, p = 0.005.</p

White matter structures showing significantly increased MD in Tourette syndrome patients (corrected for multiple comparisons, p < 0.05).

<p>Filled using tbss_fill script of FSL to aid visualization. The background image is the standard MNI_T1_1mm template and the FA skeleton (green). Red-Yellow voxels represent regions in which MD was increased significant in Tourette syndrome patients relative to healthy controls. Axial slices from Z = -14 to 32 in MNI coordinate are shown.</p