Au and Pd electrodeposition in polymer films immersed in soln. with high resoln. has been accomplished using the scanning electrochem. microscope (SECM). The SECM was used in the feedback mode, where Ru(NH3)63+ was reduced at an ultramicroelectrode (UME) and diffused to a protonated polyvinylpyridine-coated surface. When metal anions e.g., AuCl4- or PdCl42-, were incorporated in the polymeric matrix, the diffusion of reduced mediator, Ru(NH3)2+, from the UME to the polymer film resulted in metal deposition. The different factors that det. the size and pattern of deposited metal were examd. The difference between Au and Pd deposition was studied by several techniques and interpreted in terms of kinetic and thermodn. properties of the mediator and the metal complex. [on SciFinder(R)]
Poled nematic films, where the asymmetric axis responsible for second harmonic generation (SHG) is not in the poling direction are reported. Liquid crystalline polymers containing dopant chromophores, or side chain groups with high molecular hyperpolarizabilies exhibit this effect which has potential applications in nonlinear optics.
A series of side chain liquid crystal co-polymers is prepared, starting from monomers containing both mesogenic and hyperpolarizable groups. When thin films of these polymers are poled by an electric field in the plane of the film, they exhibit optical nonlinearity both parallel and perpendicular to the direction of the poling field.
Reviews three books. `Spinoza and Other Heretics; Vol. I: `The Marrano of Reason,' Vol. II: `The Adventures of Immanence,' by Yirmiyahu Yovel `From Christianity to Judaism: The Story of Isaac Orobio de Castro,' by Yosef Kaplan; and, `Tractatus Theologico-Politicus,' by Benedict Spinoza, translated by Samuel Shirley.
The osteochondral potential and emergence of osteogenic cell-surface molecules by avian marrow cells was evaluated in in vivo diffusion chamber cultures. The chambers were inoculated with unselected marrow cells from young chick tibiae and implanted intraperitoneally into athymic mice. At the light microscopic level, morphologic evidence of de novo bone and cartilage formation, including specific immunostaining by antibody probes, was observed in 14 out of 16 chambers incubated for 20 days or longer. In order to monitor the osteogenic differentiation of the marrow-derived cells, indirect immunofluorescence was performed with monoclonal antibodies against stage-specific cell surface antigens on cells of the embryonic osteogenic lineage. The binding of these and other specific monoclonal antibodies in the developing tissue indicates that the cell surface and extracellular matrix molecules expressed by descendants of marrow-derived mesenchymal progenitor cells are indistinguishable from their in vivo counterparts found in embryonic skeletal structures. Furthermore, the experiments reported here describe the first molecular identification of osteogenic cells by probes which are selective for stage-specific surface antigens on cells of the osteogenic lineage. Importantly, bone formation by these marrow-derived cells appears to occur through a lineage progression which is similar to that observed for embryonic tibial osteoblasts. In summary, these data support the use of diffusion chambers inoculated with avian marrow to study aspects of osteogenic and chondrogenic differentiation.
Three (young) adults with severe generalized osteopenia and vertebral compression fractures were studied. Extensive clinical and laboratory investigations were not contributory. Undecalcified bone biopsies demonstrated multiple mast cell granulomas in the marrow in two patients and numerous mast cells diffusely distributed throughout the bone marrow in the third patient. Mast cells may serve as a pathogenic agent in osteoporosis. Therefore, we conclude that isolated skeletal mastocytosis without clinical evidence of mast cell mediator release should be sought in the evaluation of a patient with unexplained severe bone loss.
In submerged cultures, S. tendae tended to form fluffy spherical pellets of the noncoagulative type. An increase in the av. pellet size could be attained by decreasing any of the following: shear rate, pH, temp., or inoculum size. Conditions leading to O2 limitation tended to reduce the av. pellet size and induced pulpy growth, whereas O2 sufficiency seemed to induce pellet formation. Factors inducing pellet formation simultaneously increased cell wall hydrophobicity. It is therefore proposed that the main forces inducing cellular aggregation in S. tendae are hydrophobic interactions of cell walls, and these interactions are controlled by availability of dissolved O2. [on SciFinder(R)]
Three experiments in Serbo-Croatian were conducted on the effects of phonological ambiguity and lexical ambiguity on printed word recognition. subjects decided rapidly if a printed and a spoken word matched or not. Printed words were either phonologically ambiguous (two possible propronunciations) or unambiguous. IF phonologically ambiguous, either both pronunciations were real words or only one was, the other being a nonword. Spoken words were necessarily unambiguous. Half the spoken words were auditorily degraded. In addition, the relative onsets of speech andprint were varied. speed of matching print to speech was slowed by phonological ambiguity, and the effect was amplified when the stimulus was also lexically ambiguous. Auditory degradation did not interact with print ambiguity, suggesting that perception of the spoken word was independent of the printed word.
Side-chain liquid crystal polyacrylates and polysiloxanes containing different photochromic spironaphthoxazine side groups were synthesized. Thermodynamic, spectral and kinetic properties of the polymers were investigated. The structure of the mesophase is discussed.
