Mössbauer evidence of 57Fe3O4 based ferrofluid biodegradation in the brain

The ferrofluid, based on ⁵⁷Fe isotope enriched Fe₃O₄ nanoparticles, was synthesized, investigated by Mössbauer spectroscopy method and injected transcranially in the ventricle of the rat brain. The comparison of the Mössbauer spectra of the initial ferrofluid and the rat brain measured in two hours and one week after the transcranial injection allows us to state that the synthesized magnetic ⁵⁷Fe₃O₄ nanoparticles undergo intensive biodegradation in live brain and, therefore, they can be regarded as a promising target for a new method of radionuclide-free Mössbauer brachytherapy.     

A note on inequalities for the masses of the lightest ππ resonances in multicoloured QCD

We derive and analyse inequalities relating masses of the lightest ππ resonances (ρ and σ) to coupling constants of the effective chiral Lagrangian in the limit of a large number of colours. Received: 15 July 2001 / Accepted: 23 October 2001     

Bootstrap Equations in Effective Theories

In this paper, we consider general properties of effective field theories. We note that the freedom of fixing renormalization conditions in the effective field theory is not as large as it seems. Consideration of the minimal set of correctness requirements of the perturbative scheme based on the Dyson's formula for the S-matrix leads to severe restrictions on essential parameters of the theory and hence on the possible set of renormalization conditions. In the first part of this paper, we give a short review of the structure of localizable effective field theories. We discuss necessary conditions which ensure the correctness of the first step of the iterative scheme of calculation of the S-matrix, i.e., the construction of tree-level amplitudes. In the second part, we discuss examples which demonstrate the main stages of acquisition and analysis of the system of bootstrap equations. Bibliography: 17 titles.