Previous work has shown that the posteriorising agent retinoic acid can accelerate anterior neuronal differentiation in Xenopus laevis embryos (Papalopulu, N. and Kintner, C. (1996) Development 122, 3409-3418). To elucidate the role of retinoic acid in the primary neurogenesis cascade, we investigated whether retinoic acid treatment of whole embryos could change the spatial expression of a set ...

AIM Within the context of minimally invasive dentistry this article describes the sonic and ultrasonic cavity preparation techniques and assesses their advantages and disadvantages, clinical difficulties of their use, and offers a statement about these devices. BACKGROUND Ultra-conservative Class 2 restorative techniques require the use of devices such as sonic and the new ultrasonic preparat...

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoid...

PURPOSE To assess the plaque removal efficacy of an oscillating-rotating power brush relative to a newly-introduced sonic power brush. METHODS This study used a randomized, examiner-blind, single-center, two-treatment, parallel group 4-week design. Subjects with pre-existing plaque scores of at least 1.75 on the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) were evaluated for...

Three dimensional phononic crystal ("sonic vacuum" without prestress) was assembled from 137 vertical cavities arranged in hexagonal pattern in Silicone matrix filled with stainless steel spheres. This system has unique strongly nonlinear properties with respect to wave propagation inherited from nonlinear Hertz type elastic contact interaction. Trains of strongly nonlinear solitary waves excit...

The economic viability of a supersonic commercial transport airplane would be much enhanced if it could fly supersonically over land. Efforts to design an airplane to produce a minimized sonic boom at the ground require knowledge of the impact of ,sonic booms on people. Loudness, being a fundamental and well-understood characteristic of human he_zrin9, was chosen as a means of quantifying the m...

Adult mammals could spontaneously achieve a partial sensory-motor recovery after spinal cord injury, by mechanisms including synaptic plasticity. We previously showed that this recovery is associated to the expression of synapsin-I, and that sonic hedgehog and Notch-1 could be also involved in plasticity. The role of brain-derived neurotrophic factor and glutamate receptors in regulating synapt...

The Hedgehog cell-cell signaling pathway is crucial for animal development, and its misregulation is implicated in numerous birth defects and cancers. In unstimulated cells, pathway activity is inhibited by the tumor suppressor membrane protein, Patched. Hedgehog signaling is triggered by the secreted Hedgehog ligand, which binds and inhibits Patched, thus setting in motion the downstream event...

SUMMARY The sonic boom simulator of the Langley Research Center was used to quantify subjective loudness and annoyance response to simulated indoor and outdoor sonic boom signatures. The indoor signatures were derived from the outdoor signatures by application of house filters that approximated the noise reduction characteristics of a residential structure. Two indoor listening situations were ...