1,432 research outputs found

    Research on Tomography by Using Seismic Reflection Wave in Laneway

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    AbstractAs a necessary step and an integral part of works in laneway, the geological prediction is an important means of reducing disaster losses and geological disasters in the works in laneway. This paper mainly discusses tunnel reflection tomography by using seismic reflection wave in laneway. The speed of elastic wave in front of tunnel face and the three-dimensional images can be figured out when the detector check the reflection of elastic wave from the focal points on the tunnel face. The location, size and depth of cave can be ascertained. According to the forecasts of laneway works in the Iron Mine Xishimen, tunnel reflection tomography by using seismic reflection wave can well forecast engineering geology and hydro-geological conditions in front of tunnel face. It will help to supply positive guidance for working plan and construction measures in laneway. Therefore, the construction safety and speed can be ensured, helping to lead to great practical significance and significant economic benefits

    The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi 2 O 3 - M 2+ O-Nb 2 O 5 ( M 2+ = Ni 2+ and Mg 2+ ) systems

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    The composition, dielectric properties and inherent displacive disorder of a Bi-based, misplaced-displacive cubic pyrochlore phase found in two ternary Bi2O3{single bond}M2+O{single bond}Nb2O5 (M=Ni and Mg) systems has been investigated. The dielectric permittivities (up to 1 MHz) of (Bi0.825Ni0.125□0.05)2(Ni0.25Nb0.75)2O7 and (Bi0.835Mg0.085□0.08)2(Mg0.235Nb0.765)2O7 at room temperature are found to be 116 and 151, respectively, while the dielectric loss tangents are 0.00065 and 0.00042, respectively, at 100 kHz. A highly structured characteristic diffuse intensity distribution apparent in electron diffraction is reported in both cases and partially interpreted in terms of large amplitude, β-cristobalite-type tetrahedral rotations of the O'A2 tetrahedral framework sub-structure of the ideal pyrochlore structure type. Bond valence sum calculations are used to investigate the local crystal chemistry responsible for this displacive disorder

    Bis[μ-1,2-bis­(1H-imidazol-1-ylmeth­yl)benzene-κ2 N 3:N 3′]disilver(I) 3-carboxyl­ato-4-hydroxy­benzene­sulfonate methanol solvate trihydrate

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    In the title compound, [Ag2(C14H14N4)2](C7H4O6S)·CH3OH·3H2O, the complex dication has a binuclear structure in which each AgI ion is two-coordinated in a slightly distorted linear coordination geometry. The two AgI atoms are bridged by two 1,2-bis­[(1H-imidazol-1-yl)meth­yl]benzene (IBI) ligands, forming a 22-membered ring. In the dication, π–π inter­actions are observed between the imidazole rings with centroid–centroid distances of 3.472 (3) and 3.636 (3) Å. In the crystal, the uncoordinated water mol­ecules, anions and methanol solvent mol­ecules are linked into chains along the b axis by O—H⋯O hydrogen bonds. In addition, π–π inter­actions are observed between the benzene rings of the IBI ligands, with a centroid–centroid distance of 3.776 (2) Å. The sulfonate group is disordered over two orientations with occupancies of 0.676 (12) and 0.324 (12)

    Erzhi Pill® Repairs Experimental Liver Injury via TSC/mTOR Signaling Pathway Inhibiting Excessive Apoptosis

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    The present study aimed to investigate the mechanism of hepatoprotective effect of Erzhi Pill (EZP) on the liver injury via observing TSC/mTOR signaling pathway activation. The experimental liver injury was induced by 2-acetylaminofluorene (2-AAF) treatment combined with partial hepatectomy (PH). EZP treated 2-AAF/PH-induced liver injury by the therapeutic and prophylactic administration. After the administration of EZP, the activities of aspartic transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AKP), and gamma-glutamyl transpeptidase (γ-GT) were decreased, followed by the decreased levels of hepatocyte apoptosis and caspase-3 expression. However, the secretion of albumin, liver weight, and index of liver weight were elevated. Microscopic examination showed that EZP restored pathological liver injury. Meanwhile, Rheb and mammalian target of rapamycin (mTOR) activation were suppressed, and tuberous sclerosis complex (TSC) expression was elevated in liver tissues induced by 2-AAF/PHx and accompanied with lower-expression of Bax, Notch1, p70S6K, and 4E-EIF and upregulated levels of Bcl-2 and Cyclin D. Hepatoprotective effect of EZP was possibly realized via inhibiting TSC/mTOR signaling pathway to suppress excessive apoptosis of hepatocyte

    GRB 221009A: revealing a hidden afterglow during the prompt emission phase with Fermi-GBM observations

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    Recently, LHAASO reported the detection of brightest-of-all-time GRB 221009A, revealing the early onset of a TeV afterglow. However, there is no evidence of afterglow emission at such early time at other wavelengths. Here we report the discovery of a hidden afterglow component during the prompt emission phase with Fermi Gamma-Ray Burst Monitor (GBM) observations. We analyze the spectral evolution of the X-ray/γ\gamma-ray emission of GRB 221009A measured by GBM during the dips of two prompt emission pulses (i.e., intervals T0+[300328] sT_{0}+[300-328]\rm~s and T0+[338378] sT_{0}+[338-378]\rm~s, where T0T_0 is the GBM trigger time). We find that the spectra at the dips transit from the Band function to a power-law function, indicating a transition from the prompt emission to the afterglow. After T0+660 s\sim T_{0}+ 660 \rm~s, the spectrum is well described by a power-law function and the afterglow becomes dominant. Remarkably, the underlying afterglow emission at the dips smoothly connect with the afterglow after T0+660 s\sim T_{0}+ 660 \rm~s. The entire afterglow emission measured by GBM can be fitted by a power-law function Ft0.95±0.05F\sim t^{-0.95\pm0.05}, where tt is the time since the first main pulse at T=T0+226 sT^*=T_0+226~{\rm s}, consistent with the TeV afterglow decay measured by LHAASO. The start time of this power-law decay indicates that the afterglow peak of GRB 221009A should be earlier than T0+300 sT_{0}+300 \rm ~s. We also test the possible presence of a jet break in the early afterglow light curve, finding that both the jet break model and single power-law decay model are consistent with the GBM data. The two models can not be distinguished with the GBM data alone because the inferred jet break time is quite close to the end of GBM observations.Comment: 8 pages, 4 figures and 2 table

    Dynamic Bandwidth Allocation for VBR Video Transmission

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    To guarantee quality of service (QoS), the requirements for video transmission, such as delay and cell loss rate (CLR), are very stringent. These constraints are difficult to meet if high network utilization is desired. In this paper, dynamic bandwidth allocation algorithms are proposed to improve the bandwidth utilization. The first approach based on scene change identification, in which the bandwidth is allocated based on the maximum and mean bandwidth of the scene, is applicable to delivering pre-recorded videos. The second approach, in which the bandwidth is adjusted based on the current frame size, is on-line and can be used to deliver real-time videos on-line. When the bandwidth deviation is large enough, the bandwidth renegotiation process is triggered. Compared with CBR service, network utilization can be improved significantly for the same CLR. In general, to achieve a very low CLR and high bandwidth utilization, the renegotiation frequency may become high. Algorithms, which are proven to be effective in reducing the renegotiation frequency while keeping the bandwidth utilization at a reasonable level, are also proposed

    Antitumor activity of physcion 8-o-β-glucopyranoside against cervical cancer by induction of apoptosis

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    Purpose: To investigate the antitumor activity of physcion8-O-β-glucopyranoside (PSG) against cervical cancer, as well as its mechanisms.Methods: The anti-proliferative effects of PSG on HeLa cells were determined by CCK-8 assay and the half maximal inhibitory concentration (IC50) values were calculated. Subsequently, a mouse xenograft model of HeLa cell line was established to investigate the antitumor effect of PSG in vivo. Furthermore, cell apoptosis was investigated by fluorescence microscopy via DAPI staining, and other mechanisms were determined by Western blot assay.Results: In vitro, PSG exhibited significant anti-proliferative effect on HeLa cells (p <0.05) in concentration-and time-dependent manners, with an IC50 value of 41.34 μg/mL. In vivo, PSG also had significant anti-tumor activity in nude mouse xenograft model (p < 0.05), inhibiting tumor growth. Furthermore, the results showed that treatment with PSG (20, 40 and 60 μg/mL) for 24 h resulted in significantly  increased apoptosis in HeLa cells (p < 0.05). Additionally, Western blot analysis revealed that after exposure to 20, 40 and 60 μg/mL of PSG for 24 h, protein expressions of C-caspase-3, Ccaspase-9 and Bax were markedly up-regulated (p < 0.05) while Bcl-2 was significantly down-regulated (p < 0.05). These results confirmed that PSG inhibited HeLa cell growth by inducing mitochondriamediated apoptosis via up-regulation of caspase-3 and caspase-9 and Bax, and  down-regulation of Bcl-2.Conclusion: The results demonstrate that PSG possesses notable anti-tumor activity against cervical cancer and that the mechanisms involve induction of apoptosis by mitochondria-mediated signaling pathway.Keywords: Physcion 8-O-β-glucopyranoside, Cervical cancer, Apoptosis, HeLa cells, Caspase, Antitumour, Mouse xenograf
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