Evaluation of micronuclei frequency in Tradescantia pallida pollen mother cells treated with ethanolic extracts isolated from Cryptocarya mandioccana, Cryptocarya moschata and Pterogyne nitens

Although herbal extracts contain several classes of compounds with pharmacological activity, they also present toxic substances with mutagenic effects. The aim of the present study was to verify the mutagenicity of Cryptocarya moschata, Cryptocarya mandioccana and Pterogyne nitens using micronucleus assay in pollen mother cells (tetrads) in Tradescantia pallida (Trad-MCN). T. pallida inflorescences were treated with different concentrations of ethanolic extracts from the selected plant species. For C. mandioccana C. moschata and P. nitens, Trad-MCN assays were carried out simultaneoulsly, followed by positive control (formaldehyde 10000 ppm), negative control (Hoagland's solution), and vehicle control (Tween 20 20% or DMSO 3%). MCN present in tetrads were quantified in 300 tetrads/inflorescence and the mean (%) and standard error (SE) were established for at least 10 inflorescences per treatment. The extracts demonstrated dose response mutagenicity (clastogenic/aneugenic effects), respectively, C. mandioccana (0.5, 1.0 and 2.0 mg/mL) and P. nitens (1.0 and 2.0 mg/mL) However, no mutagenic effect was observed to C. moschata at the concentrations evaluated in the present study. We can conclude that the C. mandioccana and P. nitens extracts demonstrated clastogenic/aneugenic effects in highest concentrations whereas C. moschata extract did not demonstrate the same effect. © 2006 Sociedade Brasileira de Toxicologia.

An approximate method for the solution of an influence function foil rolling model

Fleck and Johnson (Int. J. Mech. Sci. 29 (1987) 507) and Fleck et al. (Proc. Inst. Mech. Eng. 206 (1992) 119) have developed foil rolling models which allow for large deformations in the roll profile, including the possibility that the rolls flatten completely. However, these models require computationally expensive iterative solution techniques. A new approach to the approximate solution of the Fleck et al. (1992) Influence Function Model has been developed using both analytic and approximation techniques. The numerical difficulties arising from solving an integral equation in the flattened region have been reduced by applying an Inverse Hilbert Transform to get an analytic expression for the pressure. The method described in this paper is applicable to cases where there is or there is not a flat region.

An Efficient and Verifiable Solution to the Millionaire Problem

A new solution to the millionaire problem is designed on the base of two new techniques: zero test and batch equation. Zero test is a technique used to test whether one or more ciphertext contains a zero without revealing other information. Batch equation is a technique used to test equality of multiple integers. Combination of these two techniques produces the only known solution to the millionaire problem that is correct, private, publicly verifiable and efficient at the same time.