Conformational changes in a hyperthermostable glycoside hydrolase: enzymatic activity is a consequence of the loop dynamics and protonation balance

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

End-to-side loop neurorrhaphy: axonal comparative stereological study

Accidents or diseases can affect the peripheral part of the nervous system, which raises clinical and surgical therapies, among others. In this context, the technique of end-to-side neurorrhaphy is a treatment option, yet its modification loop needs some additional efficacy studies. The purpose of this study was to compare, among rats, stereological results (axons volume density) after end-to-side neurorrhaphy and after end-to-side loop neurorrhaphy. Thirty Wistar rats were used, divided into six groups (five animals per group), consisting of two control groups (for the fibular and tibial nerves), two study groups for the fibular nerve (one with an end-to-side neurorrhaphy, and the other with an end-to-side loop neurorrhaphy) and two study groups for the tibial nerve (with an endto- side neurorrhaphy and the other one with an end-to-side loop neurorrhaphy). After 180 days, all groups were sacrificed for axonal stereological analysis (volume density) in distal nerve stumps. There was significant maintenance of neuronal-axonal density in the distal stumps to neurorrhaphy (p< 0.005) compared with the normal stumps. The end-to-side loop neurorrhaphy is a therapeutic option as suture technique after complete nerve section, in order to restore most of the axonal functional integrity.

Comments on two-loop Kac-Moody algebras

It is shown that the two-loop Kac-Moody algebra is equivalent to a two-variable-loop algebra and a decoupled β-γ system. Similarly WZNW and CSW models having as algebraic structure the Kac-Moody algebra are equivalent to an infinity of versions of the corresponding ordinary models and decoupled abelian fields.

A new deformation of W-infinity and applications to the two-loop WZNW and conformal affine Toda models

We construct a centerless W-infinity type of algebra in terms of a generator of a centerless Virasoro algebra and an abelian spin 1 current. This algebra conventionally emerges in the study of pseudo-differential operators on a circle or alternatively within KP hierarchy with Watanabe's bracket. Construction used here is based on a spherical deformation of the algebra W ∞ of area preserving diffeomorphisms of a 2-manifold. We show that this deformation technique applies to the two-loop WZNW and conformal affine Toda models, establishing henceforth W ∞ invariance of these models.

Excited fermion contribution to Z(0) physics at one loop

We investigate the effects induced by excited leptons at the one-loop level in the observables measured on the Ζ peak at LEP. Using a general effective Lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to both oblique parameters and Ζ partial widths. Our results show that the new effects are comparable to the present experimental sensitivity, but they do not lead to a significant improvement on the available constraints on the couplings and masses of these states.