Cellular and subcellular events during reorientation of the palatal shelf in hamster fetuses are described. An alteration in the morphology of the epithelial and the mesenchymal cells is observed during shelf realignment from a vertical to a horizontal plane. The mesenchymal cells elongate and subsequently appear to protrude in the medially bulging palatal shelf. Microtubules, microfilaments an...

The force for directing palate shelf reorientation appears to be associated with elements of the presumptive hard palate (Brinkley & Vickerman, 1979; Bulleit & Zimmerman, 1985). The palatal elements that mediate this process do not require palate cells to be metabolically active for expression of the force. This contention was demonstrated using an in vitro system that allows substantial reorie...

We present a Monte Carlo study of molecular ordering in nematics with dispersed regular and random arrays of straight and distorted polymer fibrils. We focus on the collective molecular reorientation--the switching--resulting from the competing aligning effects of fibrils and of a progressively applied transversal external field, and for straight fibrils identify structural Fréedericksz and sat...

We study the rotational dynamics of a supercooled molecular liquid by means of molecular dynamics simulations. The system under investigation is composed of rigid diatomic molecules with an associate dipole moment. At room temperature, orientational correlations decrease rapidly with increasing distances. Upon cooling, angles between dipole moments of molecules within the first coordination she...

When placed on a temperature gradient, a Drosophila larva navigates away from excessive cold or heat by regulating the size, frequency, and direction of reorientation maneuvers between successive periods of forward movement. Forward movement is driven by peristalsis waves that travel from tail to head. During each reorientation maneuver, the larva pauses and sweeps its head from side to side un...

The intrinsic forces necessary for directing the reorientation of the secondary palate appear to reside in the anterior two thirds of the palate or presumptive hard palate. The hard palate could reorient regardless of whether it was intact or separated from the posterior third or presumptive soft palate. The soft palate could only reorient if the palate shelves are left intact. These intrinsic ...

Hydride transfer changes the charge structure of the reactant and thus, may induce reorientation/reorganization of solvent molecules. This solvent reorganization may in turn alter the energetics of the reaction. In the present work, we investigate the intramolecular hydride transfer by taking Lewis acid catalyzed glucose to fructose isomerization as an example. The C2-C1 hydride transfer is the...

Recognition of external mechanical signals is vital for mammalian cells. Cyclic stretch, e.g. around blood vessels, is one such signal that induces cell reorientation from parallel to almost perpendicular to the direction of stretch. Here, we present quantitative analyses of both, cell and cytoskeletal reorientation of umbilical cord fibroblasts. Cyclic strain of preset amplitudes was applied a...

Dipolar molecular crystals present different physical properties from traditionally strongly correlated ionic solid-state inorganic crystals due to the weak intermolecular bonding. Herein, centrosymmetric dipolar molecular crystals of the organoruthenium complex trans-[Ru(C≡CC6H4-4-NO2)(C≡CPh)(dppe)2] [dppe = 1,2-bis(diphenylphosphino)ethane] display a large electric-field-induced strain behavi...