Proof of a conjecture on irredundance perfect graphs

Let ir(G) and γ(G) be the irredundance number and the domination number of a graph G, respectively. A graph G is called irredundance perfect if ir(H)=γ(H), for every induced subgraph H of G. In this article we present a result which immediately implies three known conjectures on irredundance perfect graphs. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 292–306, 2002     

Geometrical Molecular Structure Design Concept in Approach to Homo- and Heterometallic Precursors of Advanced Materials in Sol–Gel Technology

The article describes the principles of the Single Source Precursor approach to inorganic materials and introduces the Geometrical Molecular Structure Design Concept (MSDC) based on the choice of a proper molecular structure type for the desired precursor and completing it with ligands providing both the necessary number of donor atoms and the sterical protection of the chosen core. Application of MSDC is illustrated with examples taken from development of new approaches in the synthesis of oxide and sulfide catalysts and ferroelectric oxide materials.     

The Poisson boundary of covering Markov operators

Covering Markov operators are a measure theoretical generalization of both random walks on groups and the Brownian motion on covering manifolds. In this general setup we obtain several results on ergodic properties of their Poisson boundaries, in particular, that the Poisson boundary is always infinite if the deck group is non-amenable, and that the deck group action on the Poisson boundary is amenable. For corecurrent operators we show that the Radon-Nikodym cocycles of two quotients of the Poisson boundary are cohomologous iff these quotients coincide. It implies that the Poisson boundary is either purely non-atomic or trivial, and that the action of any normal subgroup of the deck group on the Poisson boundary is conservative. We show that the Poisson boundary is trivial for any corecurrent covering operator with a nilpotent (or, more generally, hypercentral) deck group. Other applications and examples are discussed. Supported by a British SERC Advanced Fellowship. A part of this work was done during my stay at MSRI, Berkeley supported by NSF Grant DMS 8505550.     

Equivariant quantization on quotients of simple Lie groups by reductive subgroups of maximal rank

We consider a class of homogeneous manifolds including all semisimple coadjoint orbits. We describe manifolds of that class admitting deformation quantizations equivariant under the action ofG and the corresponding quantum group. We also classify Poisson brackets relating to such quantizations. Presented at the 11th Colloquium “Quantum Groups and Integrable Systems”, Prague, 20–22 June 2002.     

Electrochemical dissolution of magnetite in acid solutions

The present paper deals with the electrochemical behavior of magnetite microcrystals in an acid medium. A voltammetric method employing a carbon-paste electroactive electrode (CPEE) with an organic binder was used. It was found that the cathodic voltammograms, which were recorded at different scan rates, formed a set bounded in the space of i–E parameters by a generalizing voltammetric curve corresponding to the effective potential scan rate _eff. In other words, all curves are situated under one enveloping curve, just as the smaller dolls sit in the largest doll of a Russian doll. Reverse currents (a cathodic current in the anodic direction of the potential scan) were observed on the cyclic voltammogram. Forward and reverse currents obey the same laws and have one and the same generalizing curve, which could be taken as the magnetite characteristic.     

A surface adsorption model for electroless cobalt alloy thin films

Thin cobalt alloy films have been obtained using electroless deposition solution with two reducing agents: dimethylamine borane (DMAB) and sodium hypophosphite. This system allows spontaneous and self-activated deposition of barrier layers on Cu lines and via contacts for ultra large scale integration (ULSI) interconnects applications. This work presents a study of the solution composition effects on the material properties and composition of the films. First, we present the deposition rates, the electrical resistance, the various element profiles in the thin film, and the thin film roughness. Next, we discuss the film’s composition and its dependence on the ratio between the reducing agents composition in the solution. The experimental results suggest that the film phosphorous and boron composition is determined by the surface adsorption rates of the reducing agents. Therefore, a surface co-adsorption model of the two reducing agents is proposed, formulated, analyzed, and compared to the experimental results. Finally, we discuss the model and its significance to the formation of high-quality ultra-thin barrier layers. Dedicated to Professor Dr. Algirdas Vaskelis on the occasion of his 70th birthday.     

Toward fully synthetic carbohydrate-based HIV antigen design: on the critical role of bivalency

Synthetic gp120331-335 glycopeptide fragments carrying hybrid and high-mannose type N-linked glycans were evaluated for binding to broadly neutralizing antibody 2G12 using surface plasmon resonance technology. None of the hybrid-type constructs demonstrated binding to 2G12. In the high-mannose series, the "Cys dimer" construct, presenting two undecasaccharide glycans, showed significantly higher binding than the Cys-protected monomer. The binding of the dimeric structure was further investigated in competition with recombinant gp120. The data suggest that gp120 and its designed synthetic epitope construct bind to the same site on 2G12.