Giant palaeo-landslide dammed the Yangtze river

Field evidence is presented to demonstrate that a very large landslide blocked the Jinsha River (the main stem of the Yangtze) near the present day town of Qiaojia, Yunnan Province. The discovery is significant because no persistent river-blocking landslide has been reported so far downstream in a major catchment. At the location of the landslide dam the upstream catchment area is 445 × 103 km^2. Sediments deposited behind the dam indicate that the minimum crest height was approximately 200 m with a lake volume of 11.4 +/− 1.3 km^3. The landslide occurred on the western (Sichuan) side of the river and displaced an estimated volume of at least 3.75 km^3, with material riding up to 550 m above the river on the eastern (Yunnan) side of the valley. The location is at the intersection of the Xiaojiang and Zemuhe fault zones which form part of the eastern boundary fault of the Sichuan-Yunnan Fault Block, an area where many earthquakes exceeding magnitude 7.0 have been documented in the historical record

香港

本书为《中国概况》丛书之香港卷，书中介绍了香港的地理环境、政治制度、经济实体、旅游风光、文化教育、社会生活等各方面的基本情况

Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, functioning downstream of the p53 pathway as a tumor suppressor. miR-34 targets Notch, HMGA2, and Bcl-2, genes involved in the self-renewal and survival of cancer stem cells. The role of miR-34 in gastric cancer has not been reported previously. In this study, we examined the effects of miR-34 restoration on p53-mutant human gastric cancer cells and potential target gene expression.</p> <p>Methods</p> <p>Human gastric cancer cells were transfected with miR-34 mimics or infected with the lentiviral miR-34-MIF expression system, and validated by miR-34 reporter assay using Bcl-2 3'UTR reporter. Potential target gene expression was assessed by Western blot for proteins, and by quantitative real-time RT-PCR for mRNAs. The effects of miR-34 restoration were assessed by cell growth assay, cell cycle analysis, caspase-3 activation, and cytotoxicity assay, as well as by tumorsphere formation and growth.</p> <p>Results</p> <p>Human gastric cancer Kato III cells with miR-34 restoration reduced the expression of target genes Bcl-2, Notch, and HMGA2. Bcl-2 3'UTR reporter assay showed that the transfected miR-34s were functional and confirmed that Bcl-2 is a direct target of miR-34. Restoration of miR-34 chemosensitized Kato III cells with a high level of Bcl-2, but not MKN-45 cells with a low level of Bcl-2. miR-34 impaired cell growth, accumulated the cells in G1 phase, increased caspase-3 activation, and, more significantly, inhibited tumorsphere formation and growth.</p> <p>Conclusion</p> <p>Our results demonstrate that in p53-deficient human gastric cancer cells, restoration of functional miR-34 inhibits cell growth and induces chemosensitization and apoptosis, indicating that miR-34 may restore p53 function. Restoration of miR-34 inhibits tumorsphere formation and growth, which is reported to be correlated to the self-renewal of cancer stem cells. The mechanism of miR-34-mediated suppression of self-renewal appears to be related to the direct modulation of downstream targets Bcl-2, Notch, and HMGA2, indicating that miR-34 may be involved in gastric cancer stem cell self-renewal/differentiation decision-making. Our study suggests that restoration of the tumor suppressor miR-34 may provide a novel molecular therapy for p53-mutant gastric cancer.</p

A Review of Artificial Lateral Line in Sensor Fabrication and Bionic Applications for Robot Fish

Lateral line is a system of sense organs that can aid fishes to maneuver in a dark environment. Artificial lateral line (ALL) imitates the structure of lateral line in fishes and provides invaluable means for underwater-sensing technology and robot fish control. This paper reviews ALL, including sensor fabrication and applications to robot fish. The biophysics of lateral line are first introduced to enhance the understanding of lateral line structure and function. The design and fabrication of an ALL sensor on the basis of various sensing principles are then presented. ALL systems are collections of sensors that include carrier and control circuit. Their structure and hydrodynamic detection are reviewed. Finally, further research trends and existing problems of ALL are discussed

Effect of carbon additions on the microstructure of a single crystal Ni-based superalloy AM3

The microstructure of experimental nickel-base single crystal superalloys with different levels of carbon has been studied. The results indicated that with increasing carbon addition, the liquidus temperature decreased obviously and the as-cast microstructures exhibited a decrease in the amount of γ/γ′ eutectic structure and an increase in the volume fraction of carbides. The carbides formed in these alloys were most script-type MC carbides which appeared continuous dendritic networks in the interdendritic region. The segregation behavior of element W was influenced by the carbon addition

Effect of solidification parameters on the microstructures of a single crystal Ni-based superalloy AM3

A single crystal Ni-based superalloy AM3 was processed at withdraw rates of 3.5, 10, 50, 100, 200, and 500 μm•s-1, respectively. The as-cast microstructures and solidification segregation ratio were characterized with various withdraw rates. The shape and size of carbide microstructures were determined. As expected, the primary and secondary dendrite arm spacings (PDAS and SDAS) decrease with the increase of withdraw rate. The highest volume fraction of eutectic γ/γ′is observed at the 100 μm•s-1 withdraw rate. The volume fraction of eutectic γ/γ′does not appear to be a strong function of the withdraw rate. With increasing withdraw rate, interface morphologies change in the sequence of planar, cellular, and dendrite. There is a general refinement of the microstructure as the withdraw rate increases. EPMA analysis showed that withdraw rate does not have obvious influence on the segregation of elements

Characterization of freezing fresh concrete by multiple non-destructive methods

Seismic methods are useful tools to non-destructively assess the behaviors of fresh concrete. They have also been applied to characterize the properties of curing concrete to provide information for construction decision. This paper shows that freezing of concrete significantly affects the engineering properties of concrete. In the experimental program, ultrasonic tests were conducted on curing concrete subjected to different freezing process. The results indicate while there exists linear correlation between low strain seismic wave velocity and concrete strength under normal curing conditions, such relationships do not hold if the concrete is subjected to freezing process. A correction accounting for the effects of ice on the bulk strength needs to be applied. This correction was found to have linear relationship with water content. Procedures to correct the effects of freezing are proposed, which include the use of time domain reflectometry to measure the water content. Finally the strength of concrete in frozen status can be estimated. This information could be incorporated to determine the magnitude of winter load increase in cold regions for government agencies

Corrosion defect segmentation method based on superpixel feature cascade

To solve the segmentation problem caused by the small number of feature points and the change of image brightness on the surface of the storage tank, a corrosion defect segmentation method based on the superpixel feature cascade is proposed in this paper. First, the image is segmented to generate superpixels and color and texture features are extracted in the superpixel region and concatenated with domain superpixel features to form superpixel level context features; Then, a plurality of superpixels are labeled according to the pixel range of corrosion defects and the labeling results are obtained; Then, the relationship between superpixels is modeled by the full connection CRF model to optimize the classification results; Finally, the classification result of the input image is refined to generate a segmented image. The effectiveness of the segmentation method is verified and analyzed by designing comparative experiments