Gold nanoparticles (AuNPs) have exceptional stability against oxidation and therefore will play a significant role in the advancement of clinically useful diagnostic and therapeutic nanomedicines. Despite the huge potential for a new generation of AuNP-based nanomedicinal products, nontoxic AuNP constructs and formulations that can be readily administered site-specifically through the intravenous mode, for diagnostic imaging by computed tomography (CT) or for therapy via various modalities, are still rare. Herein, we report results encompassing: 1) the synthesis and stabilization of AuNPs within the nontoxic phytochemical gum-arabic matrix (GA-AuNPs); 2) detailed in vitro analysis and in vivo pharmacokinetics studies of GA-AuNPs in pigs to gain insight into the organ-specific localization of this new generation of AuNP vector, and 3) X-ray CT contrast measurements of GA-AuNP vectors for potential utility in molecular imaging. Our results demonstrate that naturally occurring GA can be used as a nontoxic phytochemical construct in the production of readily administrable biocompatible AuNPs for diagnostic and therapeutic applications in nanomedicine.

Raman scattering from binary Ge x Se 1−x glasses under hydrostatic pressure shows onset of a steady increase in the frequency of modes of corner-sharing GeSe 4 tetrahedral units when the external pressure P exceeds a threshold value P c . The threshold pressure P c ͑x͒ decreases with x in the 0.15Ͻ x Ͻ 0.20 range, nearly vanishes in the 0.20Ͻ x Ͻ 0.25 range, and then increases in the 0.25Ͻ x Ͻ 1 / 3 range. These P c ͑x͒ trends closely track those in the nonreversing enthalpy, ⌬H nr ͑x͒, near glass transitions ͑T g s͒, and in particular, both ⌬H nr ͑x͒ and P c͑x͒ vanish in the reversibility window ͑0.20Ͻ x Ͻ 0.25͒. It is suggested that P c provides a measure of stress at the Raman-active units, and its vanishing in the reversibility window suggests that these units are part of an isostatically rigid backbone. Isostaticity also accounts for the nonaging behavior of glasses observed in the reversibility window.

R~vvi~v1-active interwnduction-bandtransitions from the h, to h, 2 bands in heavily doped n-Sj (n 1.$ X 10 cm «) interfere with the zone-center optical phonon to produce Pano-type asymmetric phonon line shapes typical of a discrete-continuum interaction. %e have studied the line shapes as a function of exciting frequency and uniaxial stress along the [001] and [111]directions. The asymmetry is removed under[001] uniaxial stress for the doublet component of the phonon that couples to the stress-depleted doublet valley, and is enhanced for the singlet component that couples to the carriermdmiced singlet valley. &e have catculated from microscopic theory the parameters that describe the Pano interaction -the asymmetry parameter, the broadening, and the frequency shift due to the self-energy of the phonon deformationpotential interaction with the free electrons in the conduction-band valley. These paameters have been calculated for zero stress and a high stress along the [001] direction, and are found to be in excellent agreement with experiment. %e have also investigated the second-order acoustical-phonon scattering [2TA(X)]; it shows no change in line shape for heavily doped n-Si. Under uniaxial stress along the [001] and [111] directions, it exhibits only the hydrostatic shift, as does pure Si, which was measured for comparison.

We present photoluminescence studies as a function of temperature from a series of conjugated polymers and a conjugated molecule all with distinctly different backbone conformations. The organic materials investigated here are planar methylated ladder-type poly para-phenylene, semi-planar polyfluorene, and nonplanar para-hexaphenyl. In the long-chain-polymers the photoluminescence transition energies blueshift with increasing temperatures. In contrast, in the conjugated molecules transition energies redshift with increasing temperatures. Empirical models that explain the temperature dependence of the band gap energies in inorganic semiconductors are extended to explain the temperature dependence of the transition energies in conjugated molecules.