Time filter

Source Type

Xiangyang, China

Liu-Zeng J.,CAS Institute of Tibetan Plateau Research | Wen L.,CAS Institute of Tibetan Plateau Research | Wen L.,Xiangfan College | Oskin M.,University of California at Davis | Zeng L.,Chinese Academy of Geological Sciences
Geochemistry, Geophysics, Geosystems | Year: 2011

We use river sediment load data to map the pattern of modern denudation across the Longmen Shan margin of the Tibetan Plateau. Suspended sediment load, with corrections of bed load and solute load contributions, is used to calculate watershed-averaged denudation rates. Decadal erosion is spatially heterogeneous, and seasonally modulated by monsoon flows, which account for 80-90% of the sediment load. Enhanced denudation occurs in a ∼50 km wide band on the hanging wall of the Longmen Shan and Huya fault zones, reaching 0.5-0.8 mm/yr. These rates are similar to kyr-scale rates deduced from cosmogenic 10Be and to Myr-scale rates from low-temperature thermochronology. The sediment flux-derived erosion rates decrease with increasing distance plateauward, to less than 0.05 mm/yr at a distance ∼200 km northwest of the foot of the Longmen Shan. The gradient in precipitation across this margin alone cannot explain the one order of magnitude spatial difference in erosion. Rather, the river sediment load data delineates a zone of relatively rapid denudation around active faults that carry the Longmen Shan in their hanging wall. From the similarity of denudation rates measured over Myr, kyr, and decadal time scales, we propose that erosion of the Longmen Shan margin has approached a flux steady state. The erosional efflux is balanced by advection of rock toward the Longmen margin above the ∼20°NW dipping ramp of the margin-bounding fault. Our results suggest that high amounts of landslide material mobilized by earthquakes such as the Mw 7.9 2008 Wenchuan event are gradually removed by rivers, smoothing sediment flux over time. Our results also suggest that caution should be exercised when interpreting young cooling ages as evidence of the initiation of plateau uplift. Advection of an already high plateau into the belt of higher erosion rate at the Longmen Shan could also give rise to an abrupt cooling history. copyright 2011 by the American Geophysical Union. Source

Chen C.-M.,Wuhan University of Technology | Hu P.,Wuhan University of Technology | Wang L.-Y.,Xiangfan College
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2010

Grid services provide a distributed information sharing service over heterogeneous network environment. This paper analyzes the feature of grid system and Web services. This paper also analyzes the advantage of Web service in the contraction of grid system. The technique of synchronization Web service and asynchronous Web service are the emphases of this paper. In order to solve distributed information sharing question, we construct a simple grid model with Web service. At last, we realize this model with C#. Source

Gong W.,Xiangfan College | Zhang J.L.,Huazhong Agricultural University | Yan X.J.,Xiangfan College | Zhou Q.,Wuhan Central Hospital | And 2 more authors.
Oncology Reports | Year: 2011

LPS can induce TACE upregulation via signaling from TLR4-derived EGFR activation in tumor cells. The regulation and activity of TACE have been investigated with the observation that gene expression is upregulated in response to LPS followed by EGFR activation, however, the process remains poorly understood. In this study, we examined the effects of LPS on H22 hepatocarcinoma cells that displayed constitutively active TLR4 expression. Upon TLR4 shRNA transfection into H22 cells, HSP70 expression significantly increased. However, LPS induced early phosphorylation of EGFR in H22 cells, which reached maximum levels within 30 min. Inhibition of TLR4 in H22 cells resulted in a significant rise in both EGFR phosphorylation and TACE upregulation 24 h after exposure to LPS. Exogenous HSP70 also induced rapid phosphorylation of EGFR, upregulated the expression of COX-2 via a signaling pathway that involved TACE-dependent TGF-α release. Furthermore, inhibition of EGFR activation and reduction of COX-2 expression by COX-2 inhibitor prevented HSP70-induced cell invasion in vitro. These findings demonstrate that the biological importance of HSP70/COX-2 is crucial to the second, but not the first, phase of EGFR phosphorylation in tumor cells. The growth of tumor cells by inserting shRNA plasmid TLR4 combination with COX-2 inhibitor could be effectively reduced in LPS stimulation. We concluded that LPS triggered a bypass feedback loop of EGFR activation and involved HSP70/COX-2 in H22 cells by inhibition of TLR4 and that EGFR phosphorylation is implicated in tumor growth by LPS stimulation. Source

Discover hidden collaborations