Nucleotide-regulated calcium signaling in lung fibroblasts and epithelial cells from normal and P2Y2 receptor (-/-) mice

To test for the role of the P2Y2 receptor(P2Y2-R) in the regulation of nucleotide-promoted Ca2+ signaling in the lung, we generated P2Y2-R- deficient (P2Y2-R(-/-)) mice and measured intracellular Ca2+(i) responses (ΔCa2+(i)) to nucleotides in cultured lung fibroblasts and nasal and tracheal epithelial cells from wild type and P2Y2-R(-/-) mice. In the wild type fibroblasts, the rank order of potencies for nucleotide-induced ΔCa2+(i) was as follows: UTP ≥ ATP >> ADP > UDP. The responses induced by these agonists were completely absent in the P2Y2R(-/-) fibroblasts. Inositol phosphate responses paralleled those of ACa2+(i) in both groups. ATP and UTP also induced Ca2+(i) responses in wild type airway epithelial cells. In the P2Y2-R(-/-) airway epithelial cells, UTP was ineffective. A small fraction (25%) of the ATP response persisted. Adenosine and α,β- methylene ATP were ineffective, and ATP responses were not affected by adenosine deaminase or by removal of extracellular Ca2+, indicating that neither P1 nor P2X receptors mediated this residual ATP response. In contrast, 2-methylthio-ADP promoted a substantial Ca2+(i) response in P2Y2-R(-/-) cells, which was inhibited by the P2Y1 receptor antagonist adenosine 3'-5'-diphosphate. These studies demonstrate that P2Y2-R is the dominant purinoceptor in airway epithelial cells, which also express a P2Y1 receptor, and that the P2Y2-R is the sole purinergic receptor subtype mediating nucleotide-induced inositol lipid hydrolysis and Ca2+ mobilization in mouse lung fibroblasts

Dynamic Graffiti Stylisation with Stochastic Optimal Control

We present a method for the interactive generation of stylised letters, curves and motion paths that are similar to the ones that can be observed in art forms such as graffiti and calligraphy. We define various stylisations of a letter form over a common geometrical structure, which is given by the spatial layout of a sparse sequence of targets. Different stylisations are then generated by optimising the trajectories of a dynamical system that tracks the target sequence. The evolution of the dynamical system is computed with a stochastic formulation of optimal control, in which each target is defined probabilistically as a multivariate Gaussian. The covariance of each Gaussian explicitly defines the variability as well as the curvilinear evolution of trajectory segments. Given this probabilistic formulation, the optimisation procedure results in a trajectory distribution rather than a single path. It is then possible to stochastically sample from the distribution an infinite number of dynamically and aesthetically consistent trajectories which mimic the variability that is typically observed in human drawing or writing. We further demonstrate how this system can be used together with a simple user interface in order to explore different stylisations of interactively or procedurally defined letters

Our friend in the north: the origins, evolution and appeal of the cult of St Duthac of Tain in later Middle Ages

St Duthac of Tain was one of the most popular Scottish saints of the later middle ages. From the late fourteenth century until the reformation devotion to Duthac outstripped that of Andrew, Columba, Margaret and Mungo, and Duthac's shrine in Easter Ross became a regular haunt of James IV (1488-1513) and James V (1513-42). Hitherto historians have tacitly accepted the view of David McRoberts that Duthac was one of several local saints whose emergence and popularity in the fifteenth century was part of a wider self-consciously nationalist trend in Scottish religious practice. This study looks beyond the paradigm of nationalism to trace and explain the popularity of St Duthac from the shadowy origins of the cult to its heyday in the early sixteenth century