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Four end-functionalized star polymers that could attenuate the flow of ionic currents across biological ion channels were first de novo designed computationally, then synthesized and tested experimentally on mammalian K+ channels. The 4-arm ethylene glycol conjugate star polymers with lysine or a tripeptide attached to the end of each arm were specifically designed to mimic the action of scorpion toxins on K+ channels. Molecular dynamics simulations showed that the lysine side chain of the polymers physically occludes the pore of Kv1.3, a target for immuno-suppression therapy. Two of the compounds tested were potent inhibitors of Kv1.3. The dissociation constants of these two compounds were computed to be 0.1 μM and 0.7 μM, respectively, within 3-fold to the values derived from subsequent experiments. These results demonstrate the power of computational methods in molecular design and the potential of star polymers as a new infinitely modifiable platform for ion channel drug discovery. [ABSTRACT FROM AUTHOR]

Titanomagnetite is widely distributed in nature, and has potentials in environmental remediation. Nanometric titanomagnetite particles were usually prepared via soft chemistry routes in aqueous solutions. Herein a novel soft chemistry route carried out in a deep eutectic solvent (DES) comprising choline chloride and urea in a molar ratio of 1:2 was successfully developed to make titanomagnetite nanoparticles (Fe 2.5 Ti 0.5 O 4 -DES, ~30 nm). The chemical composition analyzed by different methods revealed that Fe 2.5 Ti 0.5 O 4 -DES nanoparticles possess the Ti-rich core and Fe-rich shell. The Fe 2.5 Ti 0.5 O 4 -DES nanoparticles exhibited enhanced activities in catalytic decomposition of H 2 O 2 and oxidative degradation of organic contaminants at circumneutral pH values and room temperature, which was mainly attributed to the increased content of ferrous (Fe2+) ions upon substitution of Ti4+ for ferric (Fe3+) ions in spinel structure of magnetite. Unlabelled Image • Synthesis of titanomagnetite magnetic nanoparticles (TMMNPs) in deep eutectic solvent • TMMNPs have Ti-rich core and Fe-rich shell. • TMMNPs exhibited enhanced catalytic activity due to increased Fe2+ content. [ABSTRACT FROM AUTHOR]

Pentachlorophenol (PCP) has been used extensively as a biocide and a wood preservative and has been reported to be immunosuppressive in rodents and humans. Tetrachlorohydroquinone (TCHQ) is a major metabolite of PCP. TCHQ has been identified as the main cause of PCP-induced genotoxicity due to reactive oxidant stress (ROS). However, the precise mechanisms associated with the immunotoxic effects of PCP and TCHQ remain unclear. The aim of this study was to examine the effects of PCP and TCHQ on the induction of ROS and injury to primary mouse splenocytes. Our results shown that TCHQ was more toxic than PCP and that a high dose of TCHQ led to necrotic cell death of the splenocytes through induction of massive and sudden ROS and prolonged ROS-triggered ERK activation. Inhibition of ROS production by N-acetyl-cysteine (NAC) partially restored the mitochondrial membrane potential, inhibited ERK activity, elevated caspase-3 activity and PARP cleavage, and, eventually, switched the TCHQ-induced necrosis to apoptosis. We suggest that prolonged ERK activation is essential for TCHQ-induced necrosis, and that ROS play a pivotal role in the different TCHQ-induced cell death mechanisms. [ABSTRACT FROM AUTHOR]

Both acetonyltriphenylphosphonium bromide (ATPB) and poly-p-styryldiphenylacetonylphosphonium bromide (PATPB) are excellent catalysts in the protection of aldehydes as acetals or thioacetals. In general, ATPB is highly selective as ketones do not give good yields of ketals with this catalyst. [ABSTRACT FROM AUTHOR]