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1.
The potential for reducing the occurrence of shallow landslides through targeted reforestation of critical parts of a river basin is explored through mathematical modelling. Through the systematic investigation of land management options, modelling allows the optimum strategies to be selected ahead of any real intervention in the basin. Physically based models, for which the parameters can be evaluated using physical reasoning, offer particular advantages for predicting the effects of possible future changes in land use and climate. Typically a physically based landslide model consists of a coupled hydrological model (for soil moisture) and a geotechnical slope stability model, along with an impact model, such as basin sediment yield. An application of the SHETRAN model to the 65.8-km2 Guabalcón basin in central Ecuador demonstrates a technique for identifying the areas of a basin most susceptible to shallow landsliding and for quantifying the effects of different vegetation covers on landslide incidence. Thus, for the modelled scenario, increasing root cohesion from 300 to 1500 Pa causes a two-thirds reduction in the number of landslides. Useful information can be obtained even on the basis of imperfect data availability but model output should be interpreted carefully in the light of parameter uncertainty. 相似文献
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The antigenic structure of human albumin was investigated in order to establish whether or not there was any similarity between its antigenic sites. Using immunoadsorbent columns prepared with cyanogen bromide fragments of human serum albumin, antibodies directed against different portions of the albumin molecules were isolated. Measurement of the amount of the antibodies isolated and study of their specificity by inhibition techniques show that these subpopulations of antibodies reacted not only with the fragment used for their isolation (homologous) but also with the other fragments (heterologous). Heterologous fragments were inhibiting only at a very high concentration with regard to the homologous ones. These results show that there is a weak cross-reactivity between different portions of the albumin molecule. This reaction is most probably due to the homology existing in the sequence of the human albumin molecule which has arisen by gene duplication. The same type of behavior can be predicted to extent to other molecules which have evolved by similar mechanisms. 相似文献
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Tetyana Denysenko Luisa Gennero Carola Juenemann Isabella Morra Paolo Masperi Vincenzo Ceroni Antonella Pragliola Antonio Ponzetto Antonio Melcarne 《Cell biochemistry and function》2014,32(2):164-176
Glioblastomas (GBMs) are the most lethal primary brain tumours. Increasing evidence shows that brain tumours contain the population of stem cells, so‐called cancer stem cells (CSCs). Stem cell marker CD133 was reported to identify CSC population in GBM. Further studies have indicated that CD133 negative cells exhibiting similar properties and are able to initiate the tumour, self‐renew and undergo multilineage differentiation. GBM is a highly heterogeneous tumour and may contain different stem cell populations with different functional properties. We characterized five GBM cell lines, established from surgical samples, according to the marker expression, proliferation and differentiation potential. CD133 positive cell lines showed increased proliferation rate in neurosphere condition and marked differentiation potential towards neuronal lineages. Whereas two cell lines low‐expressing CD133 marker showed mesenchymal properties in vitro, that is high proliferation rate in serum condition and differentiation in mesenchymal cell types. Further, we compared therapy resistance capacity of GBM cell lines treated with hydroxyurea. Our results suggest that CSC concept is more complex than it was believed before, and CD133 could not define entire stem cell population within GBM. At least two different subtypes of GBM CSCs exist, which may have different biological characteristics and imply different therapeutic strategies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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FREE NUCLEOTIDES IN THE CHICK EMBRYO BRAIN DURING DEVELOPMENT 总被引:1,自引:1,他引:0
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Christina Brahe Isabella Velonà Gerrit van der Steege Stefania Zappata Anneke Y. van de Veen Jan Osinga Carli M. J. Tops Riccardo Fodde P. Meera Khan Charles H. C. M. Buys Giovanni Neri 《Human genetics》1994,93(5):494-501
The locus responsible for the childhood-onset proximal spinal muscular atrophies (SMA) has recently been mapped to an area of 2–3 Mb in the region q12–13.3 of chromosome 5. We have used a series of radiation hybrids (RHs) containing distinct parts of the SMA region as defined by reference markers. A cosmid library was constructed from one RH. Thirteen clones were isolated and five of these were mapped within the SMA region. Both RH mapping and fluorescence in situ hybridization analysis showed that two clones map in the region between loci D5S125 and D5S351. One of the cosmids contains expressed sequences. Polymorphic dinucleotide repeats were identified in both clones and used for segregation analysis of key recombinant SMA families. One recombination between the SMA locus and the new marker 9Ic (D5S685) indicates that 9Ic is probably the closest distal marker. The absence of recombination between the SMA locus and marker Fc (D5S684) suggests that Fc is located close to the disease gene. These new loci should refine linkage analysis in SMA family studies and may facilitate the isolation of the disease gene. 相似文献