Possibility of a non-amino acid pathway in the biosynthesis of marine-derived oxazoles

A novel avenue for oxazoles via Beckmann rearrangement of alpha-formyl ketoxime dimethyl acetals is described that indicates the possibility of a non-amino acid biosynthetic pathway in marine natural products.     

pH-responsive movement of cucurbit[7]uril in a diblock polypseudorotaxane containing dimethyl beta-cyclodextrin and cucurbit[7]uril

[Structure: see text] A polypseudorotaxane consisting of cucurbit[7]uril (CB[7])/N,N'-(3-phenylenebis(methylene)dipropargylamine (PMPA), [2]pseudorotaxane, and 2,6-O-dimethyl beta-cyclodextrin (DM-beta-CD)/alpha,omega-bisazidopropylene glycol 400 [2]pseudorotaxane was synthesized using the "click" reaction. The polypseudorotaxane structure was maintained in aqueous solution over a wide range of pH values with the DM-beta-CD units contributing to increased solubilization of the polypseudorotaxane without dethreading. The pH-responsive movement of the CB[7] units in the polypseudorotaxane was also observed.     

Spin structures on instanton moduli spaces

We determine the necessary and sufficient conditions for the based SU(l)-instanton moduli spaces over CP² and the unbased SU(2)-instanton moduli spaces over S⁴ having spin structures.     

Forcing absoluteness and regularity properties

For a large natural class of forcing notions, we prove general equivalence theorems between forcing absoluteness statements, regularity properties, and transcendence properties over and the core model . We use our results to answer open questions from set theory of the reals.     

Design of New Reaction Fields for Spherical Polypyrrole Particle Synthesis

Summary: Polypyrrole conducting polymers have been investigated widely for various applications because of their thermal and environmental stability and good electrical conductivity. Using chemical oxidative polymerization for the synthesis of polypyrrole particles, the reaction rate is very fast. In this study, we designed two new reaction fields for the synthesis of spherical polypyrrole nanoparticles. In the first system, oxidative polymerization of monomer droplets infused in a water/oil (W/O) emulsion reaction field was investigated. The second system employed dispersed monomer in an aqueous solution with a low concentration of oxidant in which polymerization was augmented by ultrasonic irradiation. Effective control of the reaction rate was important for enabling the synthesis of fine spherical polypyrrole particles.     

Decompositions of polyhedral products for shifted complexes

The conjecture of Bahri, Bendersky, Cohen and Gitler (2010)  [3] on wedge decompositions of polyhedral products of shifted complexes is settled affirmatively. As a corollary, it is proved that the homotopy type of the complement of a coordinate subspace arrangement associated with a shifted complex, tensored with R^r${\mathbb{R}}^r$ for any r≥1$r\ge 1$, has the homotopy type of a wedge of spheres.