Wound-healing evaluation of ointment from Stryphnodendron adstringens (barbatimão) in rat skin

This study evaluated the cicatrizant effect of an ointment containing 1% of the ethyl-acetate fraction extracted from the stem bark of "barbatimão" (Stryphnodendron adstringens), in wounds made in the skin of rats, after 4, 7 and 10 days of treatment. Control wounds were treated with a base ointment without extract. The proliferation of keratinocytes in the area of reepithelialization was evaluated by counting the number of epithelial cells that were blocked in metaphase by vincristine sulfate. The length of the reepithelialized margin and the contraction of the wound were measured. Topical application of the "barbatimão" ointment stimulated proliferation of the keratinocytes, but had no effect on the length of the epithelium or on the contraction of the wounds.Neste estudo, avaliou-se a atividade cicatrizante de uma pomada contendo uma fração acetato de etila 1% obtida de cascas de "barbatimão" (Stryphnodendron adstringens) em feridas excisionais na pele de ratos após 4, 7 e 10 dias de tratamento. Feridas controle foram tratadas com pomada base, sem extrato. A proliferação dos queratinócitos na área reepitelizada foi avaliada através da contagem do número de queratinócitos bloqueados em metáfase, pelo sulfato de vincristina. O comprimento da margem reepitelizada e a contração das feridas foram mensurados. As feridas tratadas com barbatimão apresentaram um maior número de mitoses do que aquelas tratadas com a pomada base, em todos os tempos avaliados. A aplicação tópica da pomada de "barbatimão" estimulou a proliferação epitelial contudo não teve efeito sobre a migração dos queratinócitos ou sobre a contração das feridas

Torsional seismic response control of asymmetric-plan systems by using viscous dampers

A new approach to locating viscous dampers optimally is herein presented in order to control the torsional seismic response of asymmetric-plan buildings. Firstly, the effects of the plan-wise distribution of supplemental damping on torsionally dynamic behavior have been investigated by using modal analysis techniques in the state space representation in order to highlight the main physical aspects of the problem. Optimal design criteria have then been carried out by evaluating the H1 and H2 norms of the transfer function relating the maximum edge displacement to the input seismic excitation. These norms represent suitable performance indexes to investigate the optimal plan-wise distribution of extra-structural dampers by means of parametrical analysis on varying the dynamic characteristics of the asymmetric-plan system. The numerical constraints on the mechanical parameters related to the practical application of the proposed control strategy are taken into account. Simple design formulae to model the results for the H2 norm are proposed and positively verified through broad numerical experimentation which compared the seismic response of asymmetric systems to synthetic and real excitations for different design strategies in a plan-wise arrangement of supplemental damping