Facile production of multivalent enzyme-nanoparticle conjugates

Nanoparticles (NPs) enable the development of new, biologically relevant, multifunctional agents. Multifunctional NPs can mimic the invasive biological processes involved in cancer metastasis. We have demonstrated a facile and controllable method of conjugating multiple enzyme species to superparamagnetic (SPM) NPs. Horseradish peroxidase, α-glucosidase, and collagenase were conjugated to SPM NPs with a functional enzyme:NP ratio of 15:127:103:1. N-succinimidyl-S-acetylthiopropionate (SATP)-mediated addition of sulfhydryls to enzymes was achieved without significant activity loss. Conjugation of all enzymes was simultaneously accomplished using maleimide reactive groups generated from activation of amines associated with polyethylene glycol molecules on the NP surface. Cross reactivity between enzyme activity assay systems was negligible.     

Solutions of the Yang–Baxter equation: Descendants of the six-vertex model from the Drinfeld doubles of dihedral group algebras

The representation theory of the Drinfeld doubles of dihedral groups is used to solve the Yang–Baxter equation. Use of the two-dimensional representations recovers the six-vertex model solution. Solutions in arbitrary dimensions, which are viewed as descendants of the six-vertex model case, are then obtained using tensor product graph methods which were originally formulated for quantum algebras. Connections with the Fateev–Zamolodchikov model are discussed.     

Synthesis of the spiroacetal core of the cephalosporolide family of natural products

The synthesis of four possible stereoisomers of the spiroacetal core of the natural products cephalosporolides H and I and penisporolides A and B is described. The key steps involve the use of Sharpless asymmetric dihydroxylation to install the desired stereochemistry of the γ-lactone ring and an oxidative radical cyclisation to form the spiroacetal ring system.     

Some reactions of grignard reagents with chloroform and carbon tetrachloride in the presence of cyclohexene

The reactions of phenylmagnesium bromide and ethylmagnesium iodide with carbon tetrachloride in the presence of cyclohexane are reported. The identified products include 3,3′- bicyclohexenyl, dichloromethylcyclohexane, 7,7-dichloronorcarane, 7,7-dibromonorcarane and 7-bromo-7-chloronorcarane. The phenyl Grignard reagent reacts primarily by an ionic pathway, whilst a radical mechanism also occurs with the ethyl Grignard reagent.