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It is greatly significant to evaluate the stability of the shales with characteristic defects that the propagation and crack initiation behavior under the dynamic impact. For studying the influence of bedding and preset cracks on the dynamic fracture characteristics of shales, the dynamic tensile mechanical test of cracked layered shales was operated using the Split Hopkinson Pressure Bar. Using high-speed photography technology to record this whole process of crack propagation and dynamic failure. According to the results, the bedding angles and pre-existing crack angles of the specimen affected the characteristics of crack initiation points, crack initiation angles, and propagation paths. As the pre-existing crack angle increases, the crack initiation points of shale specimens gradually shift from a pre-existing crack tip to a pre-set hole edge region. When these pre-existing crack angles increased, it is important to the influence of bedding angles on crack initiation angles. The cracks of the specimen mainly propagated along or across the bedding plane to both sides of the loading end. According to the crack growth and propagation characteristics, we divided the failure modes of the shale specimen into five typical modes. The study can supply some theoretical support for the actual exploitation of deep shale gas. [ABSTRACT FROM AUTHOR]

Building detection in orthophotos is crucial for various applications, such as urban planning and real-estate management. In order to realize accurate and fast building detection, a non-interactive approach based on binary feature classification is brought forward in this paper. The proposed approach includes two major stages, i.e., building area detection and building contours extraction. In the first stage, a sequence of intersections is obtained by superpixel segmentation in the subsampled orthophoto, and then building area is reserved roughly according to the classification of intersections. In the second stage, the sequence of intersections is updated by superpixel segmentation in the building area from original orthophoto, and then building contours is extracted in accordance with the classification of intersections likewise. The local feature of the intersections is descripted employing our extremely compact binary descriptor, and is classified using binary bag-of-features. Experiments show that benefiting from binary description and making full use of texture details and color channels, the proposed descriptor is not only computationally frugal, but also accurate. Experiments are also conducted on orthophotos with different roof colors, textures, shapes, sizes and orientations, and demonstrate that the proposed approach are capable of achieving desirable results. [ABSTRACT FROM AUTHOR]

To investigate the potential effects of variation of HO-1 activity on hemorheology, this study compared the hemorheological properties between transgenic HO-1G143H mutant mice and wild-type (WT) control mice. Fresh blood samples were obtained from mice via the ocular venous sinus. The whole blood viscosity was measured using a cone-plate viscometer. Erythrocyte deformability and aggregation was measured using ektacytometry. The elongation index was significantly reduced in the HO-1G143H mutant mice compared to the WT mice at the shear rates of 600, 800, and 1,000 s. The integrated elongation index was decreased in the HO-1G143H mutant mice compared to the WT mice. There was no statistically significant difference between the HO-1G143H mutant mice and the WT mice in terms of whole blood viscosity, aggregation index, amplitude of aggregation, and aggregation half time. The present study demonstrated that a reduction in HO-1 activity results in an impaired erythrocyte deformability. Although the mechanism underlying this effect remains unclear, our study brings to light the participation of HO-1 in the variations of hemorheology. [ABSTRACT FROM AUTHOR]

Endothelial activation elicited by inflammatory agents is regarded as a key event in the pathogenesis of several vascular inflammatory diseases. In the present study, the inhibitory effects and underlying mechanism of C-type natriuretic peptide (CNP) on LPS-induced endothelial activation were examined in human umbilical vein endothelial cells (HUVECs). The effect of CNP on adhesion molecule expression was assessed using quantitative real-time RT-PCR and western blotting analyses. The nuclear factor-κB (NF-κB), MAPK, and PI3K/Akt signaling pathways in LPS-stimulated HUVECs were investigated using western blotting analyses, and the production of intracellular reactive oxygen species (ROS) was measured using a fluorescence method. Pretreatment with CNP inhibited LPS-induced expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and P-selectin in a concentration-dependent manner. CNP suppressed the phosphorylation of p65 and NF-κB activation in LPS-stimulated cells. Moreover, CNP reduced ERK1/2 and p38 phosphorylation induced by LPS but not JNK. Furthermore, CNP induced Akt phosphorylation and activation of hemeoxygenase-1 (HO-1) expression. CNP significantly inhibited the production of intracellular ROS. These results suggest that CNP effectively attenuated LPS-induced endothelial activation by inhibiting the NF-κB and p38 signaling pathways, eliminating LPS-induced intracellular ROS production, and activating the PI3K/Akt/HO-1 pathway in HUVECs; thereby, demonstrating that CNP may be a potential therapeutic target for the treatment of sepsis and inflammatory vascular diseases. [ABSTRACT FROM AUTHOR]