Submicron polyacrolein particles in situ embedded with upconversion nanoparticles for bioassay

We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescence properties, chemical stability, and also allow the control of particle diameters. The feasibility of the as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging system

Hilbert-diagnostics of vortex rings induced in air by a pressure pulse on a hole

Formation and evolution of complementary vortical rings induced in air by a pressure pulse on a hole under various boundary conditions are investigated by Hilbert-optics methods and computer modeling. It is experimentally demonstrated that reverse ring-shaped vortices inside the chamber after its depressurization are formed not only in the case with a reduced initial pressure in the chamber as compared with the ambient atmospheric pressure but also in the case with a higher gas pressure in the chamber than the atmospheric pressure. The complementary vortex rings propagating in forward and reverse directions might significantly affect the combustion process in the jets. </jats:p

Synthesis of Thiazolidine-2-thiones via One-Pot A3-coupling / Carbon Disulfide Incorporation Process

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A copper-catalyzed two-step one-pot procedure for the synthesis of thiazolidine-2-thiones has been developed. The process involves a three-component coupling of an alkyne, an aldehyde, and an amine (A3-coupling) followed by trapping the resulting propargylamine with carbon disulfide and subsequent cyclization.status: publishe