An integrated geophysical approach for investigating hydro-geological characteristics of a debris landslide in the Wenchuan Earthquake area

Debris landslides are one of the most widely distributed types of landslides in the Wenchuan earthquake area. The hydro-geological structure characteristics are the fundamental basis for stability evaluation, performing protection and administration of a landslide. The rock and soil mass of a debris landslide was highly non-uniform and preferential seepage paths were normally developed in it. Therefore, in situ identification of the underground water seepage system became particularly important. Recently, investigations on the seepage paths of underground water in debris landslides were restricted to indoor model testing and site observation, which were far from meeting the actual demand for landslide prevention and mitigation. To locate the seepage paths, we conducted survey work on a debris landslide seated in the Xishan Village, Li County, Sichuan Province, China, by combing four different geophysical methods. They were multichannel analysis of surface wave (MASW), electrical resistivity tomography (ERT), ground penetrating radar (GPR) and microtremor survey method (MSM). The geophysical interpretation was verified with field engineering surveys and monitoring data. The results suggested that a dendritic pipe-network seepage system usually developed in debris landslides. Varisized infiltration pipes showed the characteristics of inhomogeneity and concentration of the seepage. This work highlighted that geophysical parameters (shear wave velocity Vs, dielectric constant ε and resistivity value ρ) could provide reliable qualitative and quantitative information about the colluvial layer, bedrock interface, potential sliding surface and underground water seepage system of a landslide. The optimum combination of geophysical methods was suitable to survey the hydro-geological characteristics of debris landslides in the Wenchuan earthquake area

Influence Mechanism of Main Roof Height on Surrounding Rock Stability of Gob-Side Entry Driving

The main roof directly affects the stress environment and the control effect of the surrounding rock of gob-side entry driving. A mechanical model of the surrounding rock of gob-side entry driving was established to analyze the influence mechanism of different main roof heights on the surrounding rock stability of the roadway under similar geological conditions. In addition, the influences of the main roof heights on the stress distribution of the surrounding rock were qualitatively analyzed. A quantitative analysis of the stress and deformation distribution characteristics of the surrounding rock were conducted by Universal Distinct Element Code (UDEC) when the heights were 0, 5, and 10 m based on the actual geological conditions. Results show that waste rocks in the caving zone and damaged immediate roof could provide four different stress combinations to key rock block, which is affected by the main roof height and other related parameters. With the increase in the main roof height, the hinged stress between the key rock blocks and the plastic damage area of the physical coal wall are reduced, the damage range of immediate roof gradually increases, and the vertical stress of narrow coal pillars first increases to 5.22 MPa and then remains at approximately 1.92 MPa. Therefore, the supporting strength of roof and the physical coal wall should be enhanced. Research results are successfully applied in the Yanjiahe Coal Mine. The conclusions provide significant theoretical guidance for controlling surrounding rock stability of the roadway under similar conditions

Diaqua­bis­(3-nitro­benzoato-κO 1)bis­[1H-5-(3-pyrid­yl)-3-(4-pyrid­yl)-1H-1,2,4-triazole-κN 5]cobalt(II) dihydrate

In the centrosymmetric title compound, [Co(C7H4NO4)2(C12H9N5)2(H2O)2]·2H2O, the CoII atom, located on an inversion center, is coordinated by two N atoms [Co—N = 2.155 (3) Å] and four O atoms [Co—O = 2.099 (2)–2.117 (3) Å] in a distorted octa­hedral geometry. Inter­molecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds link the components into a three-dimensional supramolecular framework

Silica nanoparticles trigger the vascular endothelial dysfunction and prethrombotic state via miR-451 directly regulating the IL6R signaling pathway

Abstract Background Safety evaluation is a prerequisite for nanomaterials in a wide range of fields, including chemical industries, medicine or food sciences. Previously, we had demonstrated that SiNPs could trigger the thrombotic effects in vivo, but the underlying mechanisms remain unknown. This study was aimed to explore and verify the role of miR-451a on SiNPs-induced vascular endothelial dysfunction and pre-thrombotic state. Results The color doppler ultrasound results showed that SiNPs had the inhibitory effects on aorta velocity and cardiac output. The histological and ultrastructural analysis manifested that SiNPs could induce the vascular endothelial damage. In addition, the expression level of MDA was elevated while the activity of SOD and GSH-Px were decreased in aortic arch triggered by SiNPs, accompanied with the release of iNOS and decline of eNOS in blood serum. The immunohistochemistry results showed that the positive staining of TF and PECAM-1 were elevated in a dose-dependent manner induced by SiNPs. The activation of coagulation function occurred via shortened TT, PT and APTT while the FIB was elevated markedly induced by SiNPs. Coagulant factors (TF, FXa and vWF) and PLT numbers were increased whereas the levels of anticoagulant factors (ATIII, TFPI and t-PA) were decreased. Microarray analysis showed that the down-regulated miR-451a could target the gene expression of IL6R, which further activated the JAK/STAT signaling pathway triggered by SiNPs. Dual-luciferase reporter gene assay confirmed the directly target relationship between miR-451a and IL6R. Additionally, the chemical mimics of miR-451a led to attenuate the expression of IL6R/STAT/TF signaling pathway in vitro and in vivo induced by SiNPs, while the inhibitor of miR-451a enhanced the activation of IL6R/STAT/TF signaling pathway. Conclusions In summary, SiNPs could accelerate the vascular endothelial dysfunction and prethrombotic state via miR-451a negative regulating the IL6R/STAT/TF signaling pathway

Nonlinear Analysis for the Crack Control of SMA Smart Concrete Beam Based on a Bidirectional B-Spline QR Method

A bidirectional B-spline QR method (BB-sQRM) for the study on the crack control of the reinforced concrete (RC) beam embedded with shape memory alloy (SMA) wires is presented. In the proposed method, the discretization is performed with a set of spline nodes in two directions of the plane model, and structural displacement fields are constructed by the linear combination of the products of cubic B-spline interpolation functions. To derive the elastoplastic stiffness equation of the RC beam, an explicit form is utilized to express the elastoplastic constitutive law of concrete materials. The proposed model is compared with the ANSYS model in several numerical examples. The results not only show that the solutions given by the BB-sQRM are very close to those given by the finite element method (FEM) but also prove the high efficiency and low computational cost of the BB-sQRM. Meanwhile, the five parameters, such as depth-span ratio, thickness of concrete cover, reinforcement ratio, prestrain, and eccentricity of SMA wires, are investigated to learn their effects on the crack control. The results show that depth-span ratio of RC beams and prestrain and eccentricity of SMA wires have a significant influence on the control performance of beam cracks

Hilbert-Huang Transform analysis of quasi-periodic oscillations in MAXI J1820+070

We present time-frequency analysis, based on the Hilbert-Huang transform (HHT), of the evolution on the low-frequency quasi-periodic oscillations (LFQPOs) observed in the black hole X-ray binary MAXI J1820+070. Through the empirical mode decomposition (EMD) method, we decompose the light curve of the QPO component and measure its intrinsic phase lag between photons from different energy bands. We find that the QPO phase lag is negative (low energy photons lag behind high energy photons), meanwhile the absolute value of the lag increases with energy. By applying the Hilbert transform to the light curve of the QPO, we further extract the instantaneous frequency and amplitude of the QPO. Compared these results with those from the Fourier analysis, we find that the broadening of the QPO peak is mainly caused by the frequency modulation. Through further analysis, we find that these modulations could share a common physical origin with the broad-band noise, and can be well explained by the internal shock model of the jet

Establishment and characterization of immortalized human eutopic endometrial stromal cells.

PROBLEM(#br)The application of primary eutopic endometrial cells from endometriosis patients in research is restricted for short life span, dedifferentiation of hormone responsiveness.(#br)METHOD OF STUDY(#br)Human telomerase reverse transcriptase (hTERT)-induced immortalized cells (iheESCs) were infected by lentivirus. mRNA level was examined by qRT-PCR, and protein expression was quantified by Western blot. CCK-8 and EdU assay were assigned to assess the proliferation. The migration and invasion of cells were assessed by transwell assay. Clone formation assay and nude mouse tumorigenicity assay were used to evaluate colony-formation and tumorigenesis abilities.(#br)RESULTS(#br)hTERT mRNA and protein were significantly expressed higher in iheESCs compared to primary cells. iheESCs grew without morphological change for 42 passages which is much longer than 18 passages of primary cells. There was no obvious difference between primary cells and iheESCs in growth, mobility, and chromosome karyotype. Furthermore, the expression of epithelial-mesenchymal transition (EMT) markers and estrogen/progesterone receptors remained unchanged. The decidualization of iheESCs could be induced by progesterone and cAMP. Estrogen increased the proliferation and mobility of iheESCs, and lipopolysaccharides (LPS) induced the IL-1β and IL-6 promoting inflammatory response. The colony-forming ability of iheESCs, like primary cells, was lower than Ishikawa cells. In addition, tumorigenicity assay indicated that iheESCs were unable to trigger tumor formation in BALB/c nude mouse.(#br)CONCLUSIONS(#br)This study established and characterized iheESCs that kept the cellular physiology of primary cells and were not available with tumorigenic ability. Thus, iheESCs would be useful as in vitro cell model to investigate pathogenesis of endometriosis