Marche Polytechnic University

About: Marche Polytechnic University is a education organization based out in Ancona, Italy. It is known for research contribution in the topics: Population & Prostate cancer. The organization has 5905 authors who have published 15769 publications receiving 382286 citations. The organization is also known as: Universitá Politecnica delle Marche & Universita Politecnica delle Marche.

Application of fractional derivative models in linear viscoelastic problems

Abstract: Appropriate knowledge of viscoelastic properties of polymers and elastomers is of fundamental importance for a correct modelization and analysis of structures where such materials are present, especially when dealing with dynamic and vibration problems. In this paper experimental results of a series of compression and tension tests on specimens of styrene-butadiene rubber and polypropylene plastic are presented; tests consist of creep and relaxation tests, as well as cyclic loading at different frequencies. Experimental data are then used to calibrate some linear viscoelastic models; besides the classical approach based on a combination in series or parallel of standard mechanical elements as springs and dashpots, particular emphasis is given to the application of models whose constitutive equations are based on differential equations of fractional order (Fractional Derivative Model). The two approaches are compared analyzing their capability to reproduce all the experimental data for given materials; also, the main computational issues related with these models are addressed, and the advantage of using a limited number of parameters is demonstrated.

Public debt and economic growth in advanced economies: a survey

Abstract: This paper surveys the recent literature on the links between public debt and economic growth in advanced economies. We find that theoretical models yield ambiguous results. Whether high levels of public debt have a negative effect on long-run growth is thus an empirical question. While many papers have found a negative correlation between debt and growth, our reading of the empirical literature is that there is no paper that can make a strong case for a causal relationship going from debt to economic growth. We also find that the presence of thresholds and, more in general, of a non-monotone relationship between debt and growth is not robust to small changes in data coverage and empirical techniques. We conclude with a discussion of the challenges involved in measuring and defining public debt and some suggestions for future research which, in our view, should emphasize cross-country heterogeneity.

Antioxidant and Antiproliferative Activity of Diospyros lotus L. Extract and Isolated Compounds

Abstract: The object of the study was to determine the chemical composition of Diospyros lotus L. extract and their antioxidant and antiproliferative properties. Eight compounds were isolated from D. lotus and identified as gallic acid, methylgallate, ellagic acid, kaempferol, quercetin, myricetin, myricetin 3-O-β-glucuronide, and myricetin-3-O-α-rhamnoside. D. lotus extract tested in different in vitro systems (DPPH, ABTS, FRAP, and Fe2+ chelating activity assay) showed significant antioxidant activity. The potential antiproliferative properties of D. lotus extract and isolated compounds against nine human cancer cell lines such as COR-L23, CaCo-2, C32, ACHN, A375, A549, Huh-7D12, MCF-7, and LNCaP were investigated in vitro by SRB assay. D. lotus extract demonstrated the highest inhibitory activity against COR-L23 with an IC50 value of 12.2 μg/ml. Among identified hydrolysable tannins, ellagic acid evidenced strong antiproliferative activity against both C32 and A375 cells with IC50 values of 0.8 and 4.1 μg/ml, respectively. Interesting results were observed, also, with gallic acid that showed the highest cytotoxic activity against CaCo-2 (IC50 2.6 μg/ml). Overall, the results of this study suggest that D. lotus displays a good antioxidant activity and has antiproliferative effects. Both activities are related to identified phenolic compounds.

The roles of coenzyme Q10 and vitamin E on the peroxidation of human low density lipoprotein subfractions.

Abstract: The aim of our study was to investigate the relationships between the levels of coenzyme Q10 (CoQ10) and vitamin E and the levels of hydroperoxide in three subfractions of low density lipoproteins (LDL) that were isolated from healthy donors. LDL3, the densest of the three subfractions, has shown statistically significant lower levels of CoQ10 and vitamin E, which were associated with higher hydroperoxide levels when compared with the lighter counterparts. After CoQ10 supplementation, all three LDL subfractions had significantly increased CoQ10 levels. In particular, LDL3 showed the highest CoQ10 increase when compared with LDL1 and LDL2 and was associated with a significant decrease in hydroperoxide level. These results support the hypothesis that the CoQ10 endowment in subfractions of LDL affects their oxidizability, and they have important implications for the treatment of disease.