Panel The integration of voice science, voice pathology, medicine, public speaking, acting, and singing

The integration of voice science, voice pathology, medicine, public speaking, acting, and singing has been central to evolution in all fields. The Voice Foundation Symposia have played a seminal and central role in fostering integration among disciplines. The result has been an improvement in the knowledge and practice in each field. And the future promises to be even more informative and exciting.     

Dynamical behavior of muonium on silica surfaces

The behavior of muonium on the surface of finely divided silica (amorphous SiO₂) powder (mean grain diameter 70 Å) has been studied as a function of the surface concentration of hydroxyl groups. The temperature dependence of the Mu relaxation rate in transverse field was measured for samples prepared with 0%, 50% and 70% of the surface hydroxyl groups removed over the temperature range 4 K <T < 300 K. The relaxation rate shows a distinct maximum at about 25 K and a minimum at about 16 K for all three samples, and shows a dramatic decrease below 16 K as the concentration of surface hydroxyls is reduced. A three-state nonequilibrium model describing the diffusion and trapping of muonium on the silica surface is used to interpret the data.On leave from Department of Physics, University of Saskatchewan, Saskatoon, Sask. S7N OWO, Canada.     

The relevance of ester exchange in oxalacetic esters to the decarbonmonoxylation reaction

Oxalacetic esters undergo ester exchange at 120°C, at which temperature loss of CO does not occur. A new mechanism is proposed for the decarbonmonoxylation reaction.     

Muonium formation in diamond and oxide insulators

In order to provide a larger data base for understanding the whys and why nots of muonium formation in solids, we have been searching for Mu in predominantly crystalline environments. We have observed muonium in room temperature diamond, and report on a brief study of the temperature behaviour of its asymmetry and relaxation. These results are radically different from all previous diamond results. We have not been able to detect any Mu in SrTiO₃, ZrSiO₄, or TiO₂, but in GeO₂ there is a tiny signal in both a fused sample and a hexagonal single crystal, but none in a tetragonal crystal. Since hexagonal GeO₂ is structurally similar to quartz, one would naively expect similar amounts of Mu. Such is not the case, the reasons for which are not understood at this time. In SrTiO₃, the muon asymmetry is a strong function of temperature.     

Pitfalls and problems in flexible fiberoptic videolaryngoscopy

The flexible fiberoptic laryngoscope is a valuable tool in the examination of laryngeal and supraglottic structure and function. Nevertheless, persistent questions remain about the validity of the perceived image, and a variety of concerns arise relative to the equipment used, the difficult to examine patient, and the difficulty in obtaining measurable objective data. All of these areas are discussed. Distortions of the video image that result from the wideangle lens effect are described. Given an awareness of the distortions that may be present in the fiberoptic video image, it is clear that it is necessary to exercise caution in making judgments of anatomic or physiologic integrity based on fiberoptic information alone.     

Acknowledgements

Vancouver, Canada March 30, 1994     

Hyperfine field and diffusion of μ+ in Fe single crystals

In recent positive-muon spin rotation experiment at TRIUMF on single crystal Fe, a clear temperature dependent change has been observed, for the first time, both in frequency and depolarization rates from 300 K down to 23 K. The μ⁺ depolarization was explained by the μ⁺ diffusion through inhomogeneous dipolar fields and the diffusion constant was found to obey an Arrhenius law (activation energy 17 meV) above 70 K but surprisingly deviated from this at lower temperatures, indicating quantum diffusion. We have also found that the μ⁺ hyperfine field has a temperature dependence slightly stronger than that of the magnetization.     

Bonding in the monohomocyclooctatetraene anion radical

We have carried out a series of INDO calculations on the monohomocyclooctatetraene anion radical (MHCOT

). Based upon both the calculated molecular binding energy and comparison of calculated proton hyperfine coupling constants with previously published data, we conclude that the 8-membered ring of MHCOT

is planar. Good agreement was obtained with the experimental hyperfine splittings when the angle between the plane of the 8-membered ring and the plane of the fused cyclopropyl ring was 83·5°. A high π bond order between the carbon atoms at the base of the fused cyclopropyl group strongly supports Winstein's concept of homoconjugation. However, the σ bond orders across the interruption are only reduced by 10–20% relative to the other CC bonds in the ring, so this bond cannot be considered opened in the anion radical. This is in agreement with the prediction, based on molecular-orbital symmetries, that both disrotatory and conrotatory ring openings are disallowed processes for this species.     

Supramolecular control of valence-tautomeric equilibrium on nanometer-scale gold clusters

This communication describes the preparation and characterization of a valence tautomer complex covalently attached to gold nanoparticles. Variable-temperature IR spectroscopy is used to determine the equilibrium thermodynamic parameters for the valence tautomerization. These results are compared with a nonsurface combined valence tautomer complex. The results show that surface confinement attenuates both DeltaH degrees and DeltaS degrees . We attribute these changes to a reduced accessible molecular surface area.