Ruthenium catalysts bearing chelating carboxylate ligands: application to metathesis reactions in water

The novel catalytic system, composed of a ruthenium alkylidene containing a surfactant fragment in the catalysts molecule, is reported. Ring closing metathesis and cross metathesis reactions proceed efficiently in neat water at room temperature, in air, without need of adding an external surfactant.     

Magnetism in closed-shell quantum dots: emergence of magnetic bipolarons

Similar to atoms and nuclei, semiconductor quantum dots exhibit the formation of shells. Predictions of magnetic behavior of the dots are often based on the shell occupancies. Thus, closed-shell quantum dots are assumed to be inherently nonmagnetic. Here, we propose a possibility of magnetism in such dots doped with magnetic impurities. On the example of the system of two interacting fermions, the simplest embodiment of the closed-shell structure, we demonstrate the emergence of a novel broken-symmetry ground state that is neither spin singlet nor spin triplet. We propose experimental tests of our predictions and the magnetic-dot structures to perform them.     

L 1-norm of combinations of products of independent random variables

We show that the L ₁-norm of linear combinations (with scalar or vector coefficients) of products of i.i.d. nonnegative mean one random variables is comparable to the l ₁-norm of the coefficients.     

Molecular dynamics study on the influence of C-terminal sugar substitution on dynamics and conformation of vancomycin derivatives

Computational investigations were performed to examine the effects of the addition of 2-acetamido-2-deoxy-β-D-galactopyranosylamine or 1-amino-1-deoxy-D-glucitol connected to the C-terminus of vancomycin with different linkers. The purpose of this modification was to find more effective vancomycin derivatives by providing alternative interactions between vancomycin moiety and the peptidoglycan precursor. Each prepared vancomycin–peptidoglycan complex was optimized and submitted to the molecular dynamics study and analysis. The analysis of overall root mean square deviation, changes in position and interactions involving modified part of vancomycin as well as cluster analysis were carried out. One of the proposed vancomycin analogues seems to be efficient vancomycin substitute.     

New properties of a certain method of summation of generalized hypergeometric series

In a recent paper (Appl. Math. Comput. 215:1622–1645, 2009), the authors proposed a method of summation of some slowly convergent series. The purpose of this note is to give more theoretical analysis for this transformation, including the convergence acceleration theorem in the case of summation of generalized hypergeometric series. Some new theoretical results and illustrative numerical examples are given.     

Refinement Equations and Feller Operators

Results on the existence and non-existence of nontrivial \mathbb L¹{\mathbb L^1}-solutions of the refinement equation

The aza-Pudovik reaction accelerated in external constant magnetic field

The aza-Pudovik reaction of N-benzyl aromatic and aliphatic aldimines with dimethyl H-phosphonate was found to be accelerated significantly when carried out in an external magnetic field. Its conversion rates were analyzed and compared with those obtained during the aza-Pudovik reaction carried out under standard conditions. Magnetic acceleration was found to have a similar degree as in that observed in the Kabachnik–Fields reaction. However, the formation of the starting imines was found not to be susceptible to constant magnetic field–no acceleration was observed.     

Affine representations of Fibonacci groups and flat manifolds

We construct examples of affine representations for a family of Fibonacci groups. As an application, we prove that all Hantzsche–Wendt groups of the same dimension are epimorphic images of the same Fibonacci group.