Lagrange's discrete model of the wave equation in dimension greater than one

A celebrated theorem of Lagrange states that a solution of the wave equation with one-dimensional space variable is the uniform limit, as N tends to infinity, of a second order ODE obtained from a mechanical model discretizing a string as N identical harmonic oscillators. Answering to a question posed by G. Gallavotti we generalize this result to the case of any space dimension

Normalization of Poincaré singularities via variation of constants

We present a geometric proof of the Poincaré-Dulac Normalization Theorem for analytic vector fields with singularities of Poincaré type. Our approach allows us to relate the size of the convergence domain of the linearizing transformation to the geometry of the complex foliation associated to the vector field. A similar construction is considered in the case of linearization of maps in a neighborhood of a hyperbolic fixed point

Existence of periodic orbits for vector fields via Fuller index and the averaging method

We prove a generalization of a theorem proved by Seifert and Fuller concerning the existence of periodic orbits of vector fields via the averaging method. Also we show applications of these results to Kepler motion and to geodesic flows on spheres

In vitro testing for genotoxicity of indigo naturalis assessed by micronucleus test.

In the field of cosmetic dyes, used for coloring the hair and skin, there is a clear tendency to replace the widely used synthetic dyes by natural colorants, such as henna and mixtures of henna with indigo. The aim of this study was to estimate the genotoxicity of water and DMSO solutions of indigo naturalis (prepared from Indigofera tinctoria leaves) using the cytokinesis-blocked micronucleus (CBMN) assay in the human metabolically active HepG2 cell line. The cytotoxic effects of indigo solutions were first assessed by propidium iodide and fluorescein-diacetate simultaneous staining. For both solutions, cytotoxicity was always under 10%. Data obtained in the CBMN assay (for all concentrations tested) indicated that the frequency of MN (micronuclei) in exposed cells was no higher than the control. Both the water and DMSO solutions showed the same behavior. These results indicate that indigo naturalis exhibits neither cytotoxicity, nor genotoxicity for all concentrations tested, which may justify excluding indigofera and its components from the list of carcinogenic agents

Cardiovascular diseases and hard drinking waters: implications from a systematic review with meta-analysis of case-control studies

This systematic review with meta-analysis, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, aims at evaluating the potential correlation between magnesium and calcium concentration in drinking waters and the risk of cardiovascular diseases (CVD), which impose a considerable burden in high-income countries. Included studies were of the case-control studies type. From an initial list of 643 potentially eligible articles, seven studies were finally retained in the quantitative analysis. Since each one of them assessed different ion concentrations, subjects exposed to the highest concentration versus those exposed to the lowest concentration were compared. By including an overall figure of 44,000 subjects, the result suggests a protective effect of the ions on CVD prevention, with an effect-size (ES) of 0.82 (95% confidence interval CI = [0.70–0.95], p-value = 0.008) for calcium, and ES = 0.75 (95% CI = [0.66–0.86], p-value = 0.000) for magnesium. Hard water consumption seems to be protective against CVD. However, the high heterogeneity (I2 = 75.24, p-value = 0.001 for calcium; I2 = 72.96, p-value = 0.0024 for magnesium) and the existence of publication bias limits the robustness and generalizability of these findings. Further high-quality studies are needed to reproduce and confirm these results

Biological effect monitoring in peripheral blood lymphocytes from subjects occupationally exposed to antineoplastic drugs: assessment of micronuclei frequency.

Biological Effect Monitoring in Peripheral Blood Lymphocytes from Subjects Occupationally Exposed to Antineoplastic Drugs: Assessment of Micronuclei Frequency: Milena VILLARINI, et al. Department of Medical‐Surgical Specialties and Public Health (Section of Public Health), University of Perugia, Italy—ObjectivesAntineoplastic drugs (ANPDs) are widely used in the treatment of cancer and some nonneoplastic diseases. However, most if not all of these chemical agents are generally nonselective and, along with tumor cells, normal cells may undergo cytotoxic/genotoxic damage. Italian pharmacists and nurses occupationally exposed to ANPDs during their normal work routines were monitored to evaluate biological effects (i.e., cytogenetic damage) eventually associated with exposure. The subjects were also monitored for primary, oxidative and excision repaired DNA damage as evaluated by comet assay (published data). In the present paper, we present the results obtained with the cytokinesis‐block micronucleus (CBMN) test.MethodsThe CBMN test in peripheral blood lymphocytes was applied because of its ability to detect both clastogenic and aneugenic effects, and because it has recently been reported that micronuclei (MNs) are predictive of cancer risk in human populations. In this study, the evaluation of MN frequency was carried out using the CBMN test in the absence or in the presence of the DNA repair inhibitor Ara‐C (cytosine arabinoside).ResultsNo significant difference was observed for MN frequency comparing nurses handling ANPDs (exposed subjects) and controls; no correlations were found between job seniority, age, smoking habits and MN rates.ConclusionsConcerning the aim of this study to evaluate the genotoxic risk arising from occupational exposure to ANPDs, statistically significant differences in MN rates in the subjects under study could not be determined

Environmental and Economic Analysis of an Anaerobic Co-Digestion Power Plant Integrated with a Compost Plant

Italian power generation through anaerobic digestion (AD) has grown significantly between 2009 and 2016, becoming an important renewable energy resource for the country, also thanks to the generous incentives for produced electricity available in the last years. This work focuses on the economic and environmental issues of AD technology and proposes a technoeconomic analysis of investment profitability without government support. In particular, the analysis focuses on an AD power plant fed by zootechnical wastewater and agro-industrial residues coupled to a cogeneration (CHP) system and a digestate-composting plant that produces soil fertilizers. We aim to determine the economic profitability of such AD power plants fed by innerfarm biomass wastes, exploiting digestate as fertilizer, using the cogenerated heat and taking into account the externalities (environmental benefits). Environmental analysis was carried out via a life cycle analysis (LCA), and encompassing the production of biogas, heat/electricity and compost in the downstream process. The un-released environmental emissions were converted into economic benefits by means of a stepwise approach. The results indicate that integrating a compost plant with a biogas plant can significantly increase the carbon credits of the process. The results were evaluated by means of a sensitivity analysis, and they report an IRR in the range of 6%–9% according to the Italian legislative support mechanisms, and possibilities to increase revenues with the use of digestate as fertilizer. The results significantly improve when externalities are included