Elastic theory of unconstrained non-Euclidean plates

Non-Euclidean plates are a subset of the class of elastic bodies having no stress-free configuration. Such bodies exhibit residual stress when relaxed from all external constraints, and may assume complicated equilibrium shapes even in the absence of external forces. In this work we present a mathematical framework for such bodies in terms of a covariant theory of linear elasticity, valid for large displacements. We propose the concept of non-Euclidean plates to approximate many naturally formed thin elastic structures. We derive a thin plate theory, which is a generalization of existing linear plate theories, valid for large displacements but small strains, and arbitrary intrinsic geometry. We study a particular example of a hemispherical plate. We show the occurrence of a spontaneous buckling transition from a stretching dominated configuration to bending dominated configurations, under variation of the plate thickness

Do the colors of your letters depend on your language? Language-dependent and universal influences on grapheme-color synesthesia in seven languages

Grapheme-color synesthetes experience graphemes as having a consistent color (e.g., “N is turquoise”). Synesthetes’ specific associations (which letter is which color) are often influenced by linguistic properties such as phonetic similarity, color terms (“Y is yellow”), and semantic associations (“D is for dog and dogs are brown”). However, most studies of synesthesia use only English-speaking synesthetes. Here, we measure the effect of color terms, semantic associations, and non-linguistic shape-color associations on synesthetic associations in Dutch, English, Greek, Japanese, Korean, Russian, and Spanish. The effect size of linguistic influences (color terms, semantic associations) differed significantly between languages. In contrast, the effect size of nonlinguistic influences (shape-color associations), which we predicted to be universal, indeed did not differ between languages. We conclude that language matters (outcomes are influenced by the synesthete’s language) and that synesthesia offers an exceptional opportunity to study influences on letter representations in different languages.Depto. de Psicobiología y Metodología en Ciencias del ComportamientoFac. de PsicologíaTRUEpu

An appraisal of oral retinoids in the treatment of pachyonychia congenita

Aim: The Mitogen-Activated Protein Kinase (MAPK) pathway and the AKT pathway regulate cell growth, survival and migration through the transduction of signals from the cell surface to the nucleus. Both signaling pathways are deregulated in many human cancers and in the majority of melanomas. Single point mutations in N-RAS, a membrane-bound GTPase leads to the activation of both pathways. The aim of our research project was to elucidate the impact of N-RAS activation on melanocyte growth and survival. Methods: We utilized normal primary human melanocytes and applied a highly efficient third generation lentiviral transduction system that allowed ectopic expression of the melanoma-associated NRAS Q61K oncogene. Results: Oncogenic N-RASQ61K ectopically expressed in primary melanocytes induced a proliferation arrest that was associated with accumulation of the cyclin dependent kinase inhibitors p16, p14ARF, p53 and p21 and the concomitant activation of pRb. In addition, NRAS Q61K promoted a robust DNA damage response that included the accumulation of DNA damage foci, p53 phosphorylation and activation of a DNA damage signalling kinase, CHK2. Furthermore human melanocytes expressing N-RASQ61K were positive for several markers of senescence, including increased cellular size, senescence-associated b-galactosidase and the formation of DAPI-stainable, senescence-associated heterochromatic foci. Conclusions: Here we show that oncogenic N-RAS, which plays a pivotal role in cell transformation, triggers a senescence-type growth arrest in primary human melanocytes.1 page(s