Evaluation of the anti-proliferative effect the extracts of Allamanda blanchetti and A-schottii on the growth of leukemic and endothelial cells

PURPOSE. To investigate the anti-proliferative effect of A. blanchetti and A. schottii extracts. METHODS. The anti-proliferative effect of A. blanchetti and A. schottii ethanolic extracts on K562 leukemic cells as well as on BMEC and HUVEC were evaluated. Phytochemical analysis to identify the possible active components was carried out. RESULTS. The root extract of A. schottii was the most active of them. At 80 mu g/mL, the root extracts showed a cytostatic effect on K562, whereas at 400 mu g/mL, there was a strong cytotoxic effect. Similar cytostatic and cytotoxic effects were seen in the endothelial cells, but at lower doses. The effect of A. schottii root extract on endothelial cells was seen at concentrations ten times lower (8 mu g/mL) than the effect of the A. blanchetti root extract (80 mu g/mL). Phytochemical investigation of different fractions and parts of the plant led to the isolation of several known compounds, some of which are described for the first time in the genus Allamanda, and with previous evidence of anticancer and antitumoral properties. CONCLUSIONS. Our results suggest that both plants studied exhibit cytostatic and cytotoxic activity, but the most active compounds are located in the roots.9220020

Dynamical Boson Stars

The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called {\em geons}, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name {\em boson stars}. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in Relativity; major revision in 201

Exploring new physics frontiers through numerical relativity

The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

Varying constants, Gravitation and Cosmology

Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.Comment: 145 pages, 10 figures, Review for Living Reviews in Relativit

Influence of Extraction Parameters on Hydroalcohol Extracts of the Stem Bark of Rapanea ferruginea Mez Using Myrsinoic Acid B as Marker

Purpose: To evaluate the influence of extraction parameters on standardization of hydroalcoholic extract of Rapanea ferruginea Mez.Methods: A 33 factorial design was used to evaluate the influence of alcohol concentration (50, 70 and 90 % v/v), extraction time (2, 6 and 10 h), and particle size of the herbal drug (0.25, 0.5 and 1.0 mm) on the pH, dry residue and myrsinoic acid B (MAB) content of hydroalcoholic extracts by high performance liquid chromatography (HPLC) method.Results: For the extracts, there was inverse correlation between dry residue and MAB content (p < 0.8046). The parameter that had the greatest influence on extraction process was alcohol concentration (p < 0.007) followed by particle size (p < 0.046). However, extraction time did not influence the process in terms of MAB (p < 0.675). Although, the highest MAB content was obtained with 70 % v/v alcohol and extraction time of 6 h, the best methodology for extractive preparation was the use of 90 % v/v alcohol and extraction time of 2 h because it resulted in a higher yield of MAB per solution volume, i.e,, with regard to MAB content and mass yield.Conclusion: The results indicate that 90 % v/v alcohol and extraction time of 2 h have optimum influence on extraction process and were the best conditions for obtaining a standardized extract of R. ferruginea, using the method employed in this study. Thus, the findings of this study are a contribution to the development of a new phytopharmaceutical intermediate product.Keywords: Rapanea ferruginea, Hydroalcoholic extract, Myrsinoic acid B, Phytopharmaceutical, Factorial desing, Standardizatio