This work investigated the use of superheated fluorocarbon nanodrops for ultrasound thermal imaging and the use of mixed fluorocarbons for tuning thermal and acoustic thresholds for vaporization. Droplets were fabricated by condensing phospholipid-coated microbubbles containing C3F8 and C4F10 mixed at various molar ratios. Vaporization temperatures first were measured in a closed system by optical transmission following either isothermal pressure release or isobaric heating. The vaporization temperature was found to depend linearly on the percentage of C4F10 in the droplet core, indicating excellent tunability under these fluorocarbon-saturated conditions. Vaporization temperatures were then measured in an open system using contrast-enhanced ultrasound imaging, where it was found that the mixed droplets behaved like pure C4F10 drops. Additionally, the critical mechanical index for vaporization was measured at the limits of therapeutic hyperthermia (37 and 60 °C), and again the mixed droplets were found to behave like pure C4F10 drops. These results suggested that C3F8 preferentially dissolves out of the droplet core in open systems, as shown by a simple mass transfer model of multicomponent droplet dissolution. Finally, proof-of-concept was shown that pure C4F10 nanodrops can be used as an acoustic temperature probe. Overall, these results not only demonstrate the potential of superheated fluorocarbon emulsions for sonothermetry but also point to the limits of tunability for fluorocarbon mixtures owing to preferential release of the more soluble species to the atmosphere.

This study examines the effect of the sale and leaseback of corporate real estate on the stock prices of the selling firms. We ask whether the Tax Reform Act of 1986 (TRA 1986) had a negative impact on the market valuation effects of corporate sale and leasebacks. The results of the comparative statics analysis predict that the net present value of the lessee should be negatively related to the tax depreciation recovery life for the lessor and to the marginal ordinary income tax rate of the marginal holder of commercial mortgage debt. However, it should be positively related to the marginal tax rate of the equityholder of the corporate lessee. Changes in the marginal ordinary income tax rates of the lessor and the corporate lessee have an ambiguous effect on the equity value of the corporate lessee. Nevertheless, results of simulation analyses suggest that the relationship between the net present value of the lessee and each of the tax rates of the lessor and corporate lessee is negative. The empirical evidence suggests that subsequent to TRA 1986, the lessee's benefits associated with sale and leaseback transactions have decreased. Copyright American Real Estate and Urban Economics Association.

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Abstract. Merton Miller's (1977) tax model of equilibrium capital structure choice results in capital structure irrelevance and the existence of tax clienteles, assuming the restrictive case of risk-neutrality. Relaxation of the assumption of risk-neutrality in Miller's tax framework, allowing utility-maximizing risk-averse investors, indicates that capital structure irrelevance continues to hold under reasonable assumptions about utility. Evaluation of resulting tax clienteles shows that marginal tax rates do not restrict investors from investing in equities but do affect the tax status of purchased bonds.

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