487 research outputs found
Small strain stiffness within logarithmic contractancy model for structured anisotropic clay.
ABSTRACT: Stiffness of soils in the small strain region is high and it decays nonlinearly with increasing shear strains or with mobilization of shear stresses. However, the commonly used critical state based constitutive models use a simple elastic formulation at small strains that falls short in the prediction of the small strain nonlinearity and anisotropy. This paper proposes a simple way for rendering the existing constitutive models with the capability to capture the small strain behaviour of soils. This is illustrated by proposing a new model for structured anisotropic clay extending an existing model that uses the framework of logarithmic contractancy called ESCLAY1S. The proposed model is implemented into a Finite Element program as a user-defined soil model. The model predictions are compared with experimental data for various clays. Furthermore, the effect of nonlinearity is investigated for an excavation in soft clay
Entry by multiple picornaviruses is dependent on a pathway that includes TNK2, WASL, and NCK1
Comprehensive knowledge of the host factors required for picornavirus infection would facilitate antiviral development. Here we demonstrate roles for three human genes
THE CAVE AND THE HORIZON: DRAWN THOUGHTS OF SVERRE FEHN
[EN] Taking as a starting point a brief analysis of the features and the most common figures found in Sverre Fehn’s sketches, the main ideas that underpin his thoughts are revealed. His interest in the art of former Scandinavians and in primitive living, represented by the cave, and his personal interpretation of the horizon, are the basis of reflections that crystallize in a way of making architecture far from any mimicry with inherited forms.[ES] A partir de un breve análisis de las caracterÃsticas y las figuras más comunes en los bocetos de Sverre Fehn, se desvelan las principales ideas que vertebran su pensamiento. Su interés por el arte de los primeros pobladores de Escandinavia y el habitar primitivo, encarnado en la cueva, asà como su interpretación del horizonte, son la base de reflexiones que cristalizan en una arquitectura alejada de cualquier mimetismo con las formas heredadasLópez Cotelo, B. (2014). La cueva y el horizonte: el pensamiento dibujado de Sverre Fehn. EGA. Revista de Expresión Gráfica Arquitectónica. 19(24):242-251. doi:10.4995/ega.2014.3104.SWORD2422511924– Fjeld, Per Olaf, 1983. Sverre Fehn. The thought of construction. New York: Rizzoli International Publications Inc.– Fjeld, Per Olaf, 2009. Sverre Fehn. The pattern of thought. New York: The Monacelli Press.– Frampton, Kenneth, 1999. Estudios sobre cultura tectónica. Madrid: Ediciones Akal.– Hampshire, Mark y Stephenson, Keith, 2008. Signos y sÃmbolos. Milano: Electa.– Madshus, Evava y Yvenes, Marianne, 2008. Architect Sverre Fehn. Intuition-Reflection-Construction. Oslo: The National Museum of Art, Architecture and Design
Ubiquitination and proteasomal activity is required for transport of the EGF receptor to inner membranes of multivesicular bodies
EGF, but not TGFα, efficiently induces degradation of the EGF receptor (EGFR). We show that EGFR was initially polyubiquitinated to the same extent upon incubation with EGF and TGFα, whereas the ubiquitination was more sustained by incubation with EGF than with TGFα. Consistently, the ubiquitin ligase c-Cbl was recruited to the plasma membrane upon activation of the EGFR with EGF and TGFα, but localized to endosomes only upon activation with EGF. EGF remains bound to the EGFR upon endocytosis, whereas TGFα dissociates from the EGFR. Therefore, the sustained polyubiquitination is explained by EGF securing the kinase activity of endocytosed EGFR. Overexpression of the dominant negative N-Cbl inhibited ubiquitination of the EGFR and degradation of EGF and EGFR. This demonstrates that EGF-induced ubiquitination of the EGFR as such is important for lysosomal sorting. Both lysosomal and proteasomal inhibitors blocked degradation of EGF and EGFR, and proteasomal inhibitors inhibited translocation of activated EGFR from the outer limiting membrane to inner membranes of multivesicular bodies (MVBs). Therefore, lysosomal sorting of kinase active EGFR is regulated by proteasomal activity. Immuno-EM showed the localization of intact EGFR on internal membranes of MVBs. This demonstrates that the EGFR as such is not the proteasomal target
Peptides fused to the amino-terminal end of diphtheria toxin are translocated to the cytosol.
The Alkaloid Ageladine A, Originally Isolated from Marine Sponges, Used for pH-Sensitive Imaging of Transparent Marine Animals
The brominated pyrrole-imidazole Ageladine A was used for live imaging of the jellyfish (jellies) Nausithoe werneri, the sea anemone Metridium senile and the flatworm Macrostomum lignano. The fluorescence properties of Ageladine A allow for estimation of pH values in tissue and organs in living animals. The results showed that Nausithoe werneri had the most acidic areas in the tentacles and close to the mouth (pH 4–6.5), Metridium senile harbours aggregates of high acidity in the tentacles (pH 5) and in Macrostomum lignano, the rhabdoids, the gonads and areas close to the mouth were the most acidic with values down to pH 5
Imaging Poliovirus Entry in Live Cells
Viruses initiate infection by transferring their genetic material across a cellular membrane and into the appropriate compartment of the cell. The mechanisms by which animal viruses, especially nonenveloped viruses, deliver their genomes are only poorly understood. This is due in part to technical difficulties involved in direct visualization of viral gene delivery and to uncertainties in distinguishing productive and nonproductive pathways caused by the high particle-to–plaque forming unit ratio of most animal viruses. Here, we combine an imaging assay that simultaneously tracks the viral capsid and genome in live cells with an infectivity-based assay for RNA release to characterize the early events in the poliovirus (PV) infection. Effects on RNA genome delivery from inhibitors of cell trafficking pathways were probed systematically by both methods. Surprisingly, we observe that genome release by PV is highly efficient and rapid, and thus does not limit the overall infectivity or the infection rate. The results define a pathway in which PV binds to receptors on the cell surface and enters the cell by a clathrin-, caveolin-, flotillin-, and microtubule-independent, but tyrosine kinase- and actin-dependent, endocytic mechanism. Immediately after the internalization of the virus particle, genome release takes place from vesicles or tightly sealed membrane invaginations located within 100–200 nm of the plasma membrane. These results settle a long-lasting debate of whether PV directly breaks the plasma membrane barrier or relies on endocytosis to deliver its genome into the cell. We expect this imaging assay to be broadly applicable to the investigation of entry mechanisms for nonenveloped viruses
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