Synthesis,characterization and biological activity of two nickel(II) complexes with 6-(2-chlorobenzylamino)purine

Compounds of composition [Ni(L)(H₂O)₂Cl] and [Ni(L)(H₂O)(NO₃)] · EtOH [HL = 6-(2-chlorobenzylamino)purine] have been synthesized and characterized by elemental analyses, i.r. and electronic spectra, magnetic measurements and mass spectroscopy as tetrahedral nickel(II) complexes. The geometry of both complexes has been optimized using molecular mechanics modelling. Although the monoanionic ligand L is potentially bidentate, we assume that the coordination to nickel is via the N₉ atom only. Cytokinin and anti-cancer activities of the complexes were also tested in an Amaranthus cytokinin bioassay and in an in vitro MTT-based cytotoxicity assay, respectively. In human T-lymphoblastic leukemia cell line CCRF-CEM both complexes showed potent cytotoxic activity.     

The 8π‐problem for radially symmetric solutions of a chemotaxis model in the plane

The existence, uniqueness and large time behaviour of radially symmetric solutions to a chemotaxis system in the plane ?² are studied either for the critical value of the mass equal to 8π or in the subcritical case. Copyright © 2006 John Wiley & Sons, Ltd.     

Blowup and self-similar solutions for two-component drift–diffusion systems

We discuss asymptotic properties of solutions of two-component parabolic drift–diffusion systems coupled through an elliptic equation in two space dimensions. In particular, conditions for finite time blowup versus the existence of forward self-similar solutions are studied.     

Regular decay of solutions of strongly damped nonlinear hyperbolic equations

We give in this note some examples of strongly damped nonlinear hyperbolic equations occuring in mathematical physics with certain combinations of solutions and their time derivatives which decay exactly exponentially in time     

Nonlinear Diffusion of Dislocation Density and Self-Similar Solutions

We study a nonlinear pseudodifferential equation describing the dynamics of dislocations in crystals. The long time asymptotics of solutions is described by the self-similar profiles.     

Nonlocal parabolic problems in statistical mechanics

A nonlocal parabolic equation describing the evolution of a cloud of particles is studied.     

General nonlocal diffusion–convection mean field models: Nonexistence of global solutions

We consider model equations for the self-consistent field for interacting particles which feature general diffusion operators in canonical and microcanonical setting. A result on the nonexistence of solutions defined globally in time is proved.     

A Singular Problem in Electrolytes Theory

Existence and nonexistence of solutions (both stationary and evolution) for a parabolic–elliptic system describing the electrodiffusion of ions are studied. The answers to some questions concerning a generalization of a problem posed by I. Rubinstein are given. © 1997 by B.G. Teubner Stuttgart–John Wiley & Sons Ltd.