Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems.

We report on simulations of the degree of polarization entanglement of photon pairs simultaneously emitted from a quantum dot-cavity system that demand revisiting the role of phonons. Since coherence is a fundamental precondition for entanglement and phonons are known to be a major source of decoherence, it seems unavoidable that phonons can only degrade entanglement. In contrast, we demonstrate that phonons can cause a degree of entanglement that even surpasses the corresponding value for the phonon-free case.

Emission-Frequency Separated High Quality Single-Photon Sources Enabled by Phonons.

We demonstrate theoretically that the single-photon purity of photons emitted from a quantum dot exciton prepared by phonon-assisted off-resonant excitation can be significantly higher in a wide range of parameters than that obtained by resonant preparation for otherwise identical conditions. Despite the off-resonant excitation, the brightness stays on a high level. These surprising findings exploit the fact that the phonon-assisted preparation is a two-step process where phonons first lead to a relaxation between laser-dressed states while high exciton occupations are reached only with a delay to the laser pulse maximum by adiabatically undressing the dot states.

Oxidation of cholesterol in synaptosomes and mitochondria isolated from rat brains.

Cholesterol and alpha-tocopherol oxidations were studied in brain subcellular fractions isolated from cerebral hemispheres of 4-month-old, male Fischer 344 rats. The fractions were suspended in buffered media (pH 7.4, 37 degrees C0 and oxidized by adding (i) ferrous iron (Fe2+) with or without ascorbate or (ii) peroxynitrite (an endogenous oxidant produced by the reaction of superoxide and nitric oxide).

Analysis of hydroxy and keto cholesterols in oxidized brain synaptosomes.

A rapid method for the simultaneous determination of cholesterol and its oxidation products as well as alpha-to-copherol and tocopherolquinone in brain subcellular fractions is described. The samples are saponified and extracted with hexane. It is not necessary to remove cholesterol in the sample before analyzing for oxysterols.

Features of the polarity of the Golgi apparatus of frog photoreceptors: studies with lectins and with Brefeldin A.

The cis-trans polarity of the Golgi apparatus is important in Golgi functioning in glycosylation, sorting and other processes. The present work extends our prior studies on the polarity of the Golgi apparatus of frog (Rana) rod photoreceptors. We demonstrate that Golgi structures with the morphology and distribution of cis elements show the heaviest deposition of osmium.